The False Hope of Nuclear Forensics? Assessing the Timeliness of Forensics Intelligence

Nuclear forensics is playing an increasing role in the conceptualization of U.S. deterrence strategy, formally integrated into policy in the 2006 National Strategy on Combatting Terrorism (NSCT). This policy linked terrorist groups and state sponsors in terms of retaliation, and called for the development of “rapid identification of the source and perpetrator of an attack,” through the bolstering of attribution via forensics capabilities.12 This indirect deterrence between terrorist groups and state sponsors was strengthened during the 2010 Nuclear Security Summit when nuclear forensics expanded into the international realm and was included in the short list of priorities for bolstering state and international capacity. However, while governments and the international community have continued to invest in capabilities and databases for tracking and characterizing the elemental signatures of nuclear material, the question persists as to the ability of nuclear forensics to contribute actionable intelligence in a post-detonation situation quickly enough, as to be useful in the typical time frame for retaliation to terrorist acts.

In the wake of a major terrorist attack resulting in significant casualties, the impetus for a country to respond quickly as a show of strength is critical.3 Because of this, a country is likely to retaliate based on other intelligence sources, as the data from a fully completed forensics characterization would be beyond the time frame necessary for a country’s show of force. To highlight the need for a quick response, a quantitative analysis of responses to major terrorist attacks will be presented in the following pages. This timeline will then be compared to a prospective timeline for forensics intelligence. Fundamentally, this analysis makes it clear that in the wake of a major nuclear terrorist attack, the need to respond quickly will trump the time required to adequately conduct nuclear forensics and characterize the origins of the nuclear material. As there have been no instances of nuclear terrorism, a scenario using chemical, biological, and radiological weapons will be used as a proxy for what would likely occur from a policy perspective in the event a nuclear device is used.

This article will examine existing literature, outline arguments, review technical attributes,4 examine the history of retaliation to terrorism, and discuss conclusions and policy recommendations. This analysis finds that the effective intelligence period for nuclear forensics is not immediate, optimistically producing results in ideal conditions between 21 and 90 days, if at all. The duration of 21 days is also based on pre-detonation conditions, and should be considered very, if not overly, optimistic. Further, empirical data collected and analyzed suggestions that the typical response to conventional terrorism was on average 22 days, with a median of 12 days, while terrorism that used chemical, biological, or radiological materials warranted quicker response – an average of 19 days and a median of 10 days. Policy and technical obstacles would restrict the effectiveness of nuclear forensics to successfully attribute the origin of a nuclear weapon following a terrorist attack before political demands would require assertive responses.

Literature

Discussions of nuclear forensics have increased in recent years. Non-technical scholarship has tended to focus on the ability of these processes to deter the use of nuclear weapons (in particular by terrorists), by eliminating the possibility of anonymity.5 Here, the deterrence framework is an indirect strategy, by which states signal guaranteed retribution for those who support the actions of an attacking nation or non-state actor. This approach requires the ability to provide credible evidence both as to the origin of material and to the political decision to transfer material to a non-state actor. As a result of insufficient data available on the world’s plutonium and uranium supply, as well as the historical record of the transit of material, nuclear forensics may not be able to provide stand-alone intelligence or evidence against a supplying country. However, scholars have largely assumed that the ‘smoking gun’ would be identifiable via nuclear forensics. Michael Miller, for example, argues that attribution would deter both state actors and terrorists from using nuclear weapons as anyone responsible will be identified via nuclear forensics.6 Keir Lieber and Daryl Press have echoed this position by arguing that attribution is fundamentally guaranteed due to the small number of possible suppliers of nuclear material and the high attribution rate for major terrorist attacks.7 There is an important oversight from both a technical and policy perspective in these types of arguments however.

First, the temporal component of nuclear forensics is largely ignored. The processes of forensics do not produce immediate results. While the length of time necessary to provide meaningful intelligence differs, it is unlikely that nuclear forensics will provide information as to the source of the device in the time frame required by policymakers, who in the wake of a terrorist attack will need to respond quickly and decisively. This is likely to decrease both the credibility of forensics information and its usefulness if the political demand requires a leader to act promptly.

Secondly, the existence and size of a black-market for nuclear and radiological material is generally dismissed as a non-factor as it is assumed that a complex weapon provided by a state with nuclear weapon capacity is necessary. While it is acknowledged that a full-scale nuclear device capable of being deployed on a delivery device certainly requires advanced technical capacity that a terrorist organization would likely not have, a very crude weapon is possible. Devices such as a radiological dispersal device or a low yield nuclear device, or even a failed (fizzle) nuclear weapon, would still create a desirable outcome for a terrorist group in that panic, death, and devastating economic and societal consequences would ensue. Further, black market material could the ideal method of weaponization, as its characterization and origin-tracing would prove nearly impossible due to decoupling, and thus confusion, between perpetrator and originator.

It is evident that there is a gap between a robust technical understanding and arguments as to the viability and speed of nuclear forensics in providing actionable intelligence. This gap could lead to unrealistic expectations in times of crisis.

Technical Perspective

This section will outline the technologies, processes, and limitations of forensics in order to better inform its potential for contributing meaningful data in a crisis involving nuclear material. It should be noted that most open-source literature on the processes and capabilities of nuclear forensics come from a pre-detonation position, as specifics on post-denotation procedures and timelines are classified.8 This has resulted in the technical difficulties and inherent uncertainties in the conduct of forensic operations in a post-detonation situation being ignored. The following will attempt to extrapolate the details of the pre-detonation procedures into the post-detonation context in order to posit a potential time frame for intelligence retrieval.

Fundamentally, nuclear forensics is the analysis of nuclear or radiological material for the purposes of documenting the material’s characteristics and process history. With this information, and a database of material to compare the sample to, attribution of the origin of the material is possible.9 Following usage or attempted usage of a nuclear or radiological device, nuclear forensics would examine the known relationships between material characteristics and process history, seeking to correlate characterized material with known production history. While forensics encompasses the processes of analysis on recovered material, nuclear attribution is the process of identifying the source of nuclear or radioactive material, to determine the point of origin and routes of transit involving such material, and ultimately to contribute to the prosecution of those responsible.

Following a nuclear detonation, panic would likely prevail among the general populace and some first responders charged with helping those injured. Those tasked with collecting data from the site for forensic analysis would take time to deploy.10 While National Guard troops are able to respond to aid the population, specialized units are more dispersed throughout the country.11 Nuclear Emergency Support Teams, which would respond in the wake of a nuclear terror attack, are stationed at several of the national laboratories spread around the country. Depending on the location of the attack, response times may vary greatly. The responders’ first step would be to secure the site, as information required for attribution comes from both traditional forensics techniques (pictures, locating material, measurements, etc.) and the elemental forensics analysis of trace particles released from the detonation. At the site, responders would be able to determine almost immediately if it was indeed a full-scale nuclear detonation, a fizzle, or a radiological dispersal device. This is possible by assessing the level of damage and from the levels of radiation present, which can be determined with non-destructive assay techniques and dosimetry. Responders (through the use of gamma ray spectrometry and neutron detection) will be able to classify the type of material used if it is a nuclear device (plutonium versus uranium). With these factors assessed, radiation detectors would need to be deployed to carefully examine the blast site or fallout area to catalogue and extricate radioactive material for analysis. These materials would then need to be delivered to a laboratory capable of handling them.

Once samples arrive at the laboratories, characterization of the material will be undertaken to provide the full elemental analysis (isotopic and phase) of the radioactive material, including major, minor and trace constituents, and a variety of tools that can help classify into bulk analysis, imaging techniques, and microanalysis. Bulk analysis would provide elemental and isotopic composition on the material as a whole, and would enable the identification of trace material that would need to be further analyzed. Imaging tools capture the spatial and textural heterogeneities that are vital to fully characterizing a sample. Finally, microanalysis examines more granularly the individual components of the bulk material.

The three-step process described above is critical to assessing the processes the material was exposed to and the origin of the material. The process, the tools used at each stage, and a rough sequencing of events is shown in Figure 1.12 This table, a working document produced by the IAEA, presents techniques and methods that would be used by forensics analysts as they proceed through the three-step process, from batch analysis to microanalysis. Each column represents a time frame in which a tool of nuclear forensics could be utilized by analysts. However, this is a pre-detonation scenario. While it does present a close representation of what would happen post-detonation, some of the techniques listed below would be expected to take longer. This is due to several factors such as the spread of the material, vaporization of key items, and safety requirements for handling radioactive material. These processes take time and deal with small amounts of material at a time which would require a multitude of microanalysis on a variety of elements.

Figure 1

IAEA Suggested Sequence for Laboratory Techniques and Methods

It should also be noted that while nuclear forensics does employ developed best practices, it is not an exact science in that a process can be undertaken and definitive results. Rather, it is an iterative process, by which a deductive method of hypothesis building, testing, and retesting is used to guide analysis and extract conclusions. Analysts build hypotheses based on categorization of material, test these hypotheses against the available forensics data and initiate further investigation, and then interpret the results to include or remove actors from consideration. This can take several iterations. As such, while best practices and proven science drive analysis, the experience and quality of the analyst to develop well-informed hypotheses which can be used to focus more on the investigation is critical to success. A visual representation of the process is seen in Figure 2 below.13

Figure 2:

IAEA forensic analysis process

A net assessment by the Joint Working Group of the American Physical Society and the American Association for the Advancement of Science of the current status of nuclear forensics and the ability to successfully conduct attribution concluded that the technological expertise was progressing steadily, but greater cooperation and integration was necessary between agencies.14 They also provided a simplified timeline of events following a nuclear attack, which is seen in Figure 3.15 Miller also provides a more nuanced breakdown of questions that would arise in a post-detonation situation; however, it is the opinion of the author that his table overstates technical capacity following a detonation and uses optimistic estimates for intelligence.16

Figure 3

Nuclear forensics activities following a detonation

Many of the processes that provide the most insight simply take time to configure, run, and rerun. Gas chromatography-mass spectrometry, for instance, is able to detect and measure trace organic elements in a bulk sample, a very useful tool in attempting to identify potential origin via varying organics present.17 However, when the material is spread far (mostly vaporized or highly radioactive), it can take time to configure and run successfully. Thermal Ionization Mass Spectrometry (TIMS) allows for the measuring of multiple isotopes simultaneously, enabling ratios between isotope levels to be assessed.18 While critically important, this process takes time to prepare each sample, requiring purification in either a chemical or acid solution.

With this broad perspective in mind, how long would it take for actionable intelligence to be produced by a nuclear forensics laboratory following the detonation of a nuclear weapon? While Figure 1 puts output being produced in as little as one week, this would be high-level information and able to eliminate possible origins, but most likely not able to come to definitive conclusion. The estimates of Figure 3 (ranging from a week to months), are more likely as the iterative process of hypothesis testing and the obstacles leading up to the point at which the material arrives at the laboratory, would slow and hamper progress. Further, if the signatures of the material are not classified into a comprehensive database, though disperse efforts are underway, the difficulty in conclusively saying it is a particular actor increases.19 As such, an estimate of weeks to months, as is highlighted in Figures 4 and 5, is an appropriate time frame by which actionable intelligence would be available from nuclear forensics. The graphics below show the likely production times for definitive findings by the forensics processes and outlines a zone of effective intelligence production. How does this align with the time frame of retribution?

Figure 4:

Nuclear forensics timeline (author-created figure, compiled from above cited IAEA reports and AAAS report}

Figure 5:

Effective Intelligence Zone (author-created figure, compiled from above cited IAEA reports and AAAS report.)

Retaliation Data

How quickly do policymakers act in the wake of a terrorist attack? This question is largely unexplored in the social science literature. However, it is critical to establishing a baseline period in which nuclear forensics would likely need to be able to provide actionable intelligence following an attack. As such, an examination of the retaliatory time to major terrorist attacks will be examined to understand the time frame likely available to forensics analysts to contribute conclusions on materials recovered.

Major terrorist attacks were identified using the Study for Terrorism and Responses to Terrorism Global Terrorism Database.20 As such, the database was selected to return events that resulted in either 50 or more fatalities or over 100 injured. Also removed were cases occurring in Afghanistan or Iraq after 2001 and 2003 due to the indistinguishability of responses to terror attacks and normal operations of war within the data. This yielded 269 observations between 1990 and 2004. Cases that had immediate responses (same day) were excluded as this would indicate an ongoing armed conflict. Summary statistics for this data are as follows:

Table 1: Summary Statistics for GTD
Observations263
FatalitiesAverage68.6
Median55
Range – low0
Range – high1382
InjuriesAverage131.3
Median27.5
Range – low0
Range – high5500
Attack TypeAssault138
Assassination10
Bombing77
Hijacking2
Hostage10
Unknown26
Primary TargetGovernment87
Infrastructure19
Civilian146
Other/Unknown11
WeaponConventional209
Unconventional54

The identified terrorist events were then located in Gary King’s 10 Million Events data set21, which uses a proven data capture and classification method to catalogue events between 1990 and 2004. Government responses following the attack were then captured. Actions were restricted to only those where the government engaged the perpetrating group. This was done by capturing events classified as the following: missile attack, arrest, assassination, unconventional weapons, armed battle, bodily punishment, criminal arrests, human death, declare war, force used, artillery attack, hostage taking, torture, small arms attack, armed actions, suicide bombing, and vehicle bombing. This selection spans the spectrum of policy responses available to a country following a domestic terror attack that would demonstrate strength and resolve. Additionally, by utilizing a range of responses, it is possible to examine terrorism levied from domestic and international sources, thus enabling the consideration of both law enforcement and military actions. Speech acts, sanctions, and other policy actions that do not portray resolve and action were excluded, as they would typically occur within hours of an attack and would not be considered retaliation.

Undertaking this approached yielded retaliation dates for all observations. The summary statistics and basic outline of response time by tier of causalities are as follows:

Table 2: Summary Statistics                                 Table 3: Casualties by Retaliation Quartile
Table 2: Summary Statistics
Average Respond Time22 days
Median Respond Time12 days
Min1 day
Max164 days
Table 3: Casualties by Retaliation Quartile
Quickest RetaliationKilledInjuredTotal
1st Quartile (Fastest 25%)57.66175233
2nd Quartile67.9177.98146
3rd Quartile79.88221.77301
4th Quartile (Slowest 25%)71.8762.16134

Immediately, questions arise as to the relationship between retaliation time and destruction inflicted, as well as the time frame available to nuclear forensics analysts to provide intelligence before a response is required. With an average retaliation time of 22 days, this would fall within the 1-2 month time frame for complete analysis. Further, a median retaliation time of 12 days would put most laboratory analysis outside the bounds of being able to provide meaningful data. Figure 6 further highlights this by illustrating that within 30 days of a terrorist attack, 80 percent of incidents will have been responded to with force.

Figure 6:

Response Time

One of the fundamental graphics presented in the Lieber and Press article shows that as the number of causalities in a terror attack increases, the likelihood of attribution increases correspondingly. This weakens their arguments for two reasons. First,  forensics following a conventional attack would have significantly more data available than in the case of a nuclear attack, due to the destructive nature of the attack and the inability of responders to access certain locales. Secondly, a country that is attacked via unconventional means could arguably require a more resolute and quicker response. In looking at the data, the overall time to retaliation is 21.66 days. This number is significantly smaller when limited to unconventional weapons  (19.04 days) and smaller still when the perpetrators are not clearly identified (18.8 days). This highlights the need for distinction between unconventional and conventional attacks, which Lieber and Press neglected in their quantitative section.

To further highlight the point that nuclear forensics may not meet the political demands put upon it in a post-detonation situation, Table 4 highlights the disconnect between conventional and unconventional attacks and existing threats. To reiterate, the term unconventional is used colloquially here as a substitute for CBRN weapons, and not unconventional tactics. In only 37 percent of the cases observed was the threat a known entity or attributed after the fact. This compares to 85 percent for conventional. In all of these attacks, retaliation did occur; allowing the conclusion that with the severity of an unconventional weapon and the unordinary fear that is likely to be produced that public outcry and a prompt response would be warranted regardless of attribution.

Table 4: Attribution in Unconventional vs. Conventional
Incidents with Known AttackersNumber of AttacksPercent of Total
Unconventional205437%
Conventional17720985%

As the use of a nuclear weapon would result in a large number of deaths, the question as to whether or not higher levels of casualties influence response time is also of importance. However, no significant correlation is present between retaliation time and any of the other variables examined. Here, retaliation time (in days) was compared with binary variables for whether or not the perpetrators were known, if the facility was a government building or not, if the device used was a bomb or not, and if an unconventional device was used or not. Scale variables used include number of fatalities, injured, and the total casualties from the attack. Of particular note here is the negative correlation between unconventional attacks and effective attribution at time of response; this reemphasizes the above point on attribution prior to retaliation as being unnecessary following an unconventional attack.

Assessment

From this review, the ability of nuclear forensics to provide rapid, actionable intelligence in unlikely. While it is acknowledged that the process would produce gains along the way, an effective zone of intelligence production can be assumed between 21-90 days optimistically. This is highlighted in Figure 5 above, which aligns the effective zone with the processes that would likely provide definitive details. However, this does not align with the average (22 days) and median (12 days) time of response for conventional attacks. More importantly, unconventional attack responses fall well before this effective zone, with an average of 19 days and a median of 10. While the effective intelligence zone is close to these averages of these data points, the author remains skeptical that the techniques to be performed would produce viable data in a shorter time frame presented given the likely condition of the site and the length of time necessary for each run of each technique.22 This woasuld seem to support an argument that the working timelines for actionable data being outside the boundary of average retaliatory time. More examination is necessary to further narrow down the process times, a task plagued with difficulties due to material classification.ass

A secondary argument that can be made when thinking about unattributed terror attacks is that even without complete attribution, a state will retaliate against a known terror, cult, or insurgent organization following a terror attack to show strength and deter further attacks. This was shown to be the case in 34 of 54 observations (63 percent unattributed). While this number is remarkably high, all states were observed taking decisive action against a group. This would tend to negate the perspective that forensics will matter following an attack, as a state will respond more decisively to unconventional attacks than conventional whether attribution has been established or not.

There are also strategic implications for indirect deterrent strategies as well. Indirect deterrence offers a bit more flexibility in the timing of results, but less so in the uncertainty of results, as it will critical in levying guilty claims against a third-party actor. Thus, nuclear forensics can be very useful, and perhaps even necessary, in indirect deterrent strategies if data is available to compare materials and a state is patient in waiting for the results; however, significant delays in intelligence or uncertainty in results may reduce the credibility of accusations and harm claims of guilt in the international context. From a strategic perspective, the emphasis in the United States policy regarding rapid identification that was discussed at the outset of the paper reflects optimism rather than reality.

Policy Recommendations

While nuclear forensics may not be able to contribute information quickly enough to guide policymakers in their retaliatory decision-making following terrorist attacks, nuclear forensics does have significant merit. Nuclear forensics will be able to rule people out. It will be able to guide decisions for addressing the environmental disaster. Forensics also has significant political importance, as it can be used in a post-hoc situation following retaliation to possibly justify any action taken. It will also continue to be important in pre-detonation interdiction situations, where it has been advanced and excelled to-date, providing valuable information on the trafficking of illicit materials.

However, realistic expectations are necessary and should be made known so that policymakers are able to plan accordingly. The public will demand quick action, requiring officials to produce tangible results. If delay is not possible, attribution may not be possible. To overcome this, ensuring policymakers are aware of the technical limitations and hurdles that are present in conducting forensics analysis of radioactive material would help to manage expectations.

To reduce analytical time and improve attribution success rates, further steps should be taken. Continuing to enlarge the IAEA database on nuclear material signatures is critical, as this will reduce analytical time and uncertainty, making more precise attribution possible. Additional resources for equipment, building up analytical capacity, and furthering cooperation among all states to ensure that signatures are catalogued and accessible is critical. The United States has taken great steps in improving the knowledge base on how nuclear forensics is conducted with fellowships and trainings available through the Department of Energy (DOE) and the Department of Homeland Security (DHS). While funding constraints are tight, expansion of these programs and targeted recruitment of highly-qualified students and individuals is key. Perhaps, these trainings and opportunities could be expanded to cover individuals that are trained to do analytical work, but is not their primary tasking – like a National Guard for nuclear forensics. DOE and other agencies have similar programs for response capacity during emergencies; bolstering analytical capacity for rapid ramp-up in case of emergency would help to reduce analytical time. However, while these programs may reduce time, some of the delay is inherent in the science. Technological advances in analytics may help, but in the short-term are unavailable. In sum, further work in developing the personnel and technological infrastructure for nuclear forensics is needed; in the meantime, prudence is necessary.

Philip Baxter is currently a PhD Candidate in the International Affairs, Science, and Technology program in the Sam Nunn School of International Affairs at Georgia Tech. He completed his BA in political science and history at Grove City College and a MA in public policy, focusing on national security policy, from George Mason University. Prior to joining the Sam Nunn School, Phil worked in international security related positions in the Washington, DC area, including serving as a researcher at the National Defense University and as a Nonproliferation Fellow at the National Nuclear Security Administration. His dissertation takes a network analysis approach in examining how scientific cooperation and tacit knowledge development impacts proliferation latency. More broadly, his research interests focus on international security issues, including deterrence theory, strategic stability, illicit trafficking, U.S.-China-Russia relations, and nuclear safeguards.

Nuclear Information Project: External Publications and Briefings

This chronology lists selected external publications and briefings by the staff of the Nuclear Information Project. External links might go dead over time; if you need assistance to locate missing items, please contact individual project staff via the “About” page. To search for publications on the FAS Strategic Security Blog, see our Publications page.

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2000 and Earlier

Pentagon Report: China Deploys MIRV Missile

By Hans M. Kristensen

The biggest surprise in the Pentagon’s latest annual report on Chinese military power is the claim that China’s ICBM force now includes the “multiple independently-targetable re-entry vehicle (MIRV)-equipped Mod 3 (DF-5).”

This is (to my knowledge) the first time the US Intelligence Community has made a public claim that China has fielded a MIRVed missile system.

If so, China joins the club of four other nuclear-armed states that have deployed MIRV for decades: Britain, France, Russia and the United States.

For China to join the MIRV club strains China’s claim of having a minimum nuclear deterrent. It is another worrisome sign that China – like the other nuclear-armed states – are trapped in a dynamic technological nuclear arms competition.

A Little Chinese MIRV History

There have been rumors for many years that China was working on MIRV technology. Some private analysts have even claimed – incorrectly – that China had developed MIRV for the DF-31 ICBM and JL-2 SLBM.

Fifteen years ago, CIA’s National Intelligence Estimate on foreign missile developments concluded that “China has had the technical capability to develop multiple RV payloads for 20 years. If China needed a multiple-RV (MRV) capability in the near term, Beijing could use a DF-31-type RV to develop and deploy a simple MRV or multiple independently targetable reentry vehicle (MIRV) for the CSS-4 in a few years.” (For a review of earlier information and assessments, see here.)

The Pentagon echoed this conclusion in July 2002, when it stated that any Chinese multiple warhead capability will “most likely [be] for the CSS-4.”

Chinese MIRVing of a mobile ICBM such as the DF-31 “would be many years off” the CIA told Congress. This was also the conclusion of the CIA’s National Intelligence Estimate in 2001, which concluded that “Chinese pursuit of a multiple RV capability for its mobile ICBMs and SLBMs would encounter significant technical hurdles and would be costly.”

A DF-5 ICBM is launched from a silo. The Pentagon says China has equipped some of its DF-5s with MIRV.

A DF-5 ICBM is launched from a silo. The Pentagon says China has equipped some of its DF-5s with MIRV.

In an exchange with Senator Cochran in 2002, CIA’s Robert Walpole explained that MIRVing a mobile ICBM would require a much smaller warhead and possibly require nuclear testing:

Sen. Cochran. How many missiles will China be able to place multiple reentry vehicles on?

Mr. Walpole. In the near term, it would be about 20 CSS-4s that they have, the big, large ICBMs. The mobile ICBMs are smaller and it would require a very small warhead for them to put multiple RVs on them.

Sen. Cochran. … [D]o you think that China will attempt to develop a multiple warhead capability for its new missiles?

Mr. Walpole. Over time they may look at that. That would probably require nuclear testing to get something that small, but I do not think it is something that you would see them focused on for the near term.

What makes the Pentagon’s report on the MIRVed DF-5A payload noteworthy is that it was not included in several other intelligence assessments published in the past few months: the prepared threat assessment by the Director of National Intelligence; the prepared threat assessment by the Defense Intelligence Agency; and STRATCOM’s prepared testimony.

Nor were a MIRVed DF-5A mentioned in the Pentagon’s report from 2014 or the Air Force National Air and Space Intelligence Center (NASIC) report from July 2013.

The Pentagon report also repeats an earlier assertion that “China also is developing a new road-mobile ICBM, the CSS-X-20 (DF-41), possibly capable of carrying MIRVs.” STRATCOM commander Admiral Cecil Haney also mentioned this, saying China is “developing a follow-on mobile system capable of carrying multiple warheads.”

“Possibly capable of” and “capable of” are not equal assessments; the first includes uncertainty, the second does not. Assuming CIA’s prediction from 15 years ago is correct, the DF-5 MIRV payload might consist of three warheads developed for the DF-31/31A.

Whatever the certainty, the MIRVed version of the DF-5 – which I guess we could call DF-5B – is not thought to be loaded with warheads under normal circumstances. In a crisis, the warheads would first have to be brought out of storage and mated with the missile.

Moreover, The Pentagon lists two versions of the DF-5 deployed: the DF-5A (CSS-4 Mod 2) and the new DF-5 MIRV (CSS-4 Mod 3). So only a portion of the 20 missiles in as many silos apparently have been equipped for MIRV.

Why Chinese MIRV?

The big question is why the Chinese leadership has decided to deploy MIRV on the silo-based, liquid-fuel DF-5A.

Chinese officials have for many years warned, and US officials have predicted, that advanced US non-nuclear capabilities such as missile defense systems could cause China to deploy MIRV on some of its missiles. The Pentagon report repeats this analysis by stating that China’s “new generation of mobile missiles, with warheads consisting of MIRVs and penetration aids, are intended to ensure the viability of China’s strategic deterrent in the face of continued advances in U.S. and, to a lesser extent, Russian strategic ISR, precision strike, and missile defense capabilities.”

Conclusions

Chinese MIRV on the DF-5 ICBM is a bad day for nuclear constraint.

Seen in the context of China’s other ongoing nuclear modernization programs – deployment of several types of mobile ICBMs and a new class of sea-launched ballistic missile submarines – the deployment of a MIRVed version of the DF-5 ICBM reported by the Pentagon’s annual report strains the credibility of China’s official assurance that it only wants a minimum nuclear deterrent and is not part of a nuclear arms race.

MIRV on Chinese ICBMs changes the calculus that other nuclear-armed states will make about China’s nuclear intensions and capacity. Essentially, MIRV allows a much more rapid increase of a nuclear arsenal than single-warhead missile. If China also develops MIRV for a mobile ICBM, then it would further deepen that problem.

To its credit, the Chinese nuclear arsenal is still much smaller than that of Russia and the United States. So this is not about a massive Chinese nuclear buildup. Yet the development underscores that a technological nuclear competition among the nuclear-armed states is in full swing – one that China also contributes to.

Although it is still unclear what has officially motivated China to deploy a MIRVed version of the DF-5 ICBM now, previous Chinese statements and US intelligence assessments indicate that it may be a reaction to the US development and deployment of missile defense systems that can threaten China’s ability to retaliate with nuclear weapons.

If so, how ironic that the US missile defense system – intended to reduce the threat to the United States – instead would seem to have increased the threat by triggering development of MIRV on Chinese ballistic missiles that could destroy more US cities in a potential war.

The deployment of a MIRVed DF-5 also raises serious questions about China’s strategic relationship with India. The Pentagon report states that in addition to US missile defense capabilities, “India’s nuclear force is an additional driver behind China’s nuclear force modernization.” There is little doubt that Chinese MIRV has the potential to nudge India into the MIRV club as well.

Indian weapons designers have already hinted that India may be working on its own MIRV system and the US Defense Intelligence Agency recently stated that “India will continue developing an ICBM, the Agni-VI, which will reportedly carry multiple warheads.”

If Chinese MIRV triggers Indian MIRV it would deepen nuclear competition between the two Asian nuclear powers and reduce security for both. This calls for both countries to show constraint but it also requires the other MIRVed nuclear-armed states (Britain, France, Russia and the United States) to limit their MIRV and offensive nuclear warfighting strategies.

This publication was made possible by a grant from the New Land Foundation and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.

Obama Administration Releases New Nuclear Warhead Numbers

By Hans M. Kristensen

In a speech to the Review Conference of the Non-Proliferation Treaty in New York earlier today, U.S. Secretary of State John Kerry disclosed new information about the size of the U.S. nuclear weapons stockpile.

Updated Stockpile Numbers

First, Kerry updated the DOD nuclear stockpile history by declaring that the stockpile as of September 2014 included 4,717 nuclear warheads. That is a reduction of 87 warheads since September 2013, when the DOD stockpile included 4,804 warheads, or a reduction of about 500 warheads retired since President Obama took office in January 2009.

The September 2014 number of 4,717 warheads is 43 warheads off the estimate we made in our latest FAS Nuclear Notebook in March this year.

Disclosure of Dismantlement Queue

Second, Kerry also announced a new number we have never seen in public before: the official number of retired nuclear warheads in line for dismantlement. As of September 2014, the United States had approximately 2,500 additional warheads that have been retired (but are still relatively intact) and awaiting dismantlement.

The number of “approximately 2,500” retired warheads awaiting dismantlement is close to the 2,340 warheads we estimated in the FAS Nuclear Notebook in March 2015.

Increasing Warhead Dismantlements

Kerry also announced that the administration “will seek to accelerate the dismantlement of retired nuclear warheads by 20 percent.”

“Over the last 20 years alone, we have dismantled 10,251 warheads,” Kerry announced.

This updates the count of 9,952 dismantled warheads from the 2014 disclosure, which means that the administration between September 2013 and September 2014 dismantled 299 retired warheads.

Under current plans, of the “approximately 2,500” warheads in the dismantlement queue, the ones that were retired through (September) 2009 will be dismantled by 2022. Additional warheads retired during the past five years will take longer.

How the administration will accelerate dismantlement remains to be seen. The FY2016 budget request for NNSA pretty much flatlines funding for weapons dismantlement and disposition through 2020. In the same period, the administration plans to complete production of the W76-1 warhead, begin production of the B61-12, and carry out refurbishments of four other warheads. If the administration wanted to dismantle all “approximately 2,500” retired warheads by 2022 (including those warheads retired after 2009), it would have to dismantle about 312 warheads per year – a rate of only 13 more than it dismantled in 2014. So this can probably be done with existing capacity.

Implications

Secretary Kerry’s speech is an important diplomatic gesture that will help the United States make its case at the NPT review conference that it is living up to its obligations under the treaty. Some will agree, others will not. The nuclear-weapon states are in a tough spot at the NPT because there are currently no negotiations underway for additional reductions; because the New START Treaty, although beneficial, is modest; and because the nuclear-weapon states are reaffirming the importance of nuclear weapons and modernizing their nuclear arsenals as if they plan to keep nuclear weapons indefinitely (see here for worldwide status of nuclear arsenals).

And the disclosure is a surprise. As recently as a few weeks ago, White House officials said privately that the United States would not be releasing updated nuclear warhead numbers at the NPT conference. Apparently, the leadership decided last minute to do so anyway. [Update: another White House official says the release was cleared late but that it had been the plan to release some numbers all along.]

The roughly 500 warheads cut from the stockpile by the Obama administration is modest and a disappointing performance by a president that has spoken so much about reducing the numbers and role of nuclear weapons. Unfortunately, the political reality has been an arms control policy squeezed between a dismissive Russian president and an arms control-hostile U.S. Congress.

In addition to updating the stockpile history, the most important part of the initiative is the disclosure of the number of weapons awaiting dismantlement. This is an important new transparency initiative by the administration that was not included in the 2010 or 2014 stockpile transparency initiatives. Disclosing dismantlement numbers helps dispel rumors that the United States is hiding a secret stash of nuclear warheads and enables the United States to demonstrate actual dismantlement progress.

And, besides, why would the administration not want to disclose to the NPT conference how many warheads it is actually working on dismantling? This can only help the United States at the NPT review conference.

There will be a few opponents of the transparency initiative. Since they can’t really say this harms U.S. national security, their primary argument will be that other nuclear-armed states have so far not response in kind.

Russia and China have not made public disclosures of their nuclear warhead inventories. Britain and France has said a little on a few occasions about their total inventories and (in the case of Britain) how many warheads are operationally available or deployed, but not disclosed the histories of stockpiles or dismantlement. And the other nuclear-armed states that are outside the NPT (India, Israel, North Korea, Pakistan) have not said anything at all.

But this is a work in progress. It will take a long time to persuade other nuclear-armed states to become more transparent with basic information about nuclear arsenals. But seeing that it can be done without damaging national security and at the same time helping the NPT process is important to cut through old-fashioned excessive nuclear secrecy and increase nuclear transparency. Hat tip to the Obama administration.

This publication was made possible by a grant from the New Land Foundation and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.

Is China Planning To Build More Missile Submarines?

By Hans M. Kristensen

Is China increasing production of nuclear ballistic missile submarines?

Over the past few months, several US defense and intelligence officials have stated for the record that China is planning to build significantly more nuclear-powered missile submarines than previously assumed.

This would potentially put a bigger portion of China’s nuclear arsenal out to sea, a risky proposition, and further deepen China’s unfortunate status as the only nuclear-armed state party to the nuclear Non-Proliferation that is increasing it nuclear arsenal.

US Projections For Chinese SSBNs

China does not provide information about how many nuclear submarines it plans to build, but US government officials and agencies occasionally give projections.

The most recent comes from the commander of US Pacific Command (PACOM), Admiral Samuel Locklear, who in his prepared testimony to the US Congress earlier this month stated that in addition to the three Jin-class SSBNs currently in operation, “up to five more may enter service by the end of the decade.”

PACOM Commander Admiral Samuel Lochlear, seen here shaking hands with Chinese defense minister Liang Guanglie in Beijing in 2012, says that China may be building up to eight ballistic missile submarines.

PACOM Commander Admiral Samuel Lochlear, seen here shaking hands with Chinese defense minister Liang Guanglie in Beijing in 2012, says that China may be building up to eight ballistic missile submarines.

National Intelligence Director James Clapper was a little less specific in his testimony to the Senate in February when he predicted that China “might produce additional Jin-class nuclear-powered ballistic missile submarines.”

The Pentagon’s annual report on Chinese military issues from June 2014 stated that three Jin-class SSBNs (Type-094) were operational and that “up to five may enter service before China proceeds to its next generation SSBN (Type-096) over the next decade.” That projection was not seen as implying that five additional SSBNs would be produced but that a total of five might be built. But in hindsight it could of course be seen as similar projection as the latest PACOM statement.

PACOM’s projection of “up to five” additional Jin-class SSBNs is a doubling of the projection of “4-5” SSBNs that the Office of Naval Intelligence made in 2013. That projection followed the first estimate from late-2006 of “a fleet of probably five” submarines.

Production of five additional SSBNs by the end of the decade would require fielding one SSBN per year for the next five years, a production pace that China has yet to demonstrate. The first three Jin SSBNs took more than a decade to complete and a fourth boat is rumored to have started sea trials in 2014. The fourth SSBN might be the one seen on commercial satellite images in the dry dock at Huludao in October 2013.

Google Earth images from 2014 and 2015 do not show SSBNs at Huludao, only attack submarines. However, unassembled 10-meter diameter hull sections seen at the shipyard in December 2014 indicate that construction of additional Jin SSBN hulls may be underway (see image below).

Although no Jin-class SSBN has been visible at Huludao shipyard on Google Earth since October 2013, possible Jin-class hull sections seen later indicate additional construction. Click on image to see full size.

Although no Jin-class SSBN has been visible at Huludao shipyard on Google Earth since October 2013, possible Jin-class hull sections seen later indicate additional construction. Click on image to see full size.

Although no Jin-class SSBN has been visible at Huludao shipyard on Google Earth since October 2013, possible Jin-class hull sections seen later indicate additional construction. Click on image to see full size.

Potential Effect on Nuclear Arsenal

Construction of additional Jin SSBNs obviously would have implications for the size of China’s nuclear arsenal. With each submarine capable of carrying 12 Julang-2 (JL-2) long-rang ballistic missiles, the low- and high-end projection of a fleet of 4-8 submarines would be able to carry 48-96 missiles with as many warheads. (Despite occasional claims on the Internet that the JL-2 carries MIRV, the US Intelligence Community assigns only one warhead to each missile.)

We estimate that China has a stockpile of approximately 250 nuclear warheads of which nearly 150 are for land-based missiles, 48 for submarines, and perhaps 20 for bombers. Some have speculated that China might have several thousand nuclear weapons, but former USSTRATCOM Commander General Kehler in 2012 rejected this saying that “the Chinese arsenal is in the range of several hundred” nuclear weapons. If China builds eight Jin SSBNs, it would presumably have to produce more warheads for their additional missiles. This could increase the stockpile to around 300 warheads (see table below).

china-nukes

Other weapon systems have also been rumored to have nuclear capability, although status is uncertain: The DH-10 ground-launched land-attack cruise missile is listed by Air Force National Air and Space Intelligence Center (NASIC) as “conventional or nuclear”; the DH-20 (CJ-20) air-launched cruise missiles was listed in 2013 by US Air Force Global Strike Command the DH-20 (CJ-20) as nuclear-capable; and a CIA intelligence memorandum in 1993 concluded that China “almost certainly has developed a warhead” for the DF-15 short-range ballistic missile and predicted that deployment of a nuclear-armed DF-15 would start in 1994. A nuclear test in January 1972 was with a small bomb delivered by a fighter-bomber (Q-5), although it is uncertain if the capability was ever operationalized and fielded.

SSBN Operational Questions

If China is indeed building significantly more Jin SSBNs, as the statement by PACOM implies, then it is a surprise that raises a number of questions.

The first question is whether it is accurate. The PACOM projection is above and beyond the estimate of 4-6 SSBNs projected by the Office of Naval Intelligence in 2013. The Jin-class is a work in progress and the submarines are noisier than Soviet Delta III SSBNs developed in the 1970s. Presumably the Chinese navy is working hard to make the Jin SSBNs survivable, but up to eight would be an expensive experiment. And China appears to be designing a newer SSBN type anyway, the Type-096. Projections such as these often prove too much too soon, so only time will tell.

But if China were to deploy up to eight Jin SSBNs with up to 96 missiles, it would be a significant shift in China’s nuclear posture, which up till recently was almost entirely focused on land-based nuclear weapons. And this is odd. Why, after having spent significant sources on building mobile ICBMs to hide in forests and caves across China’s vast territory to protect its nuclear deterrent from a first strike, would the Chinese government chose to deploy a significant portion of its nuclear warheads on noisy submarines and send them out to sea where US Navy attack submarines can sink them?

A more important question is how China would actually operate the SSBNs. The Central Military Commission (CMC) does not normally hand out nuclear weapons to the military services but the whole point of having SSBNs is to hide nuclear weapons in the oceans as a secure retaliatory capability. It would be a significant change for Chinese nuclear policy if the CMC loaded warheads on the submarines and deployed them outside Chinese territory. Perhaps they will not be continuously deployed in peacetime but serve as a surge capability in a crisis.

And China does not have much (if any) experience in operating SSBNs on lengthy deterrent patrols. It has only recently started operating nuclear-powered attack submarines on lengthy patrols, including into the Indian Ocean, but the SSBNs have yet to conduct one. PACOM predicted the first would happen last year, but that didn’t happen. Now they predict it will happen this year. We’ll see.

As a party to the nuclear Non-Proliferation Treaty (NPT), a significant increase of the SSBN fleet would further deepen China’s unfortunate status as the only nuclear-armed state part to the treaty that is increasing the size of its nuclear arsenal.

This publication was made possible by a grant from the New Land Foundation and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.

New Nuclear Notebook: Russian Nuclear Forces 2015

By Hans M. Kristensen

Russian nuclear weapons have received a lot of attention lately. Russian officials casually throw around direct or thinly veiled nuclear threats (here, here and here). And U.S. defense hawks rail (here and here) about a Russian nuclear buildup.

In reality, rather than building up, Russia is building down but appears to be working to level off the force within the next decade to prevent further unilateral reduction of its strategic nuclear force in the future. For details, see the latest FAS Nuclear Notebook on the Bulletin of the Atomic Scientists web site.

This trend makes it more important for the United States and Russia to reach additional nuclear arms control agreements to reduce strategic nuclear forces. Hard to imagine in the current climate, but remember: even at the height of the Cold War the two sides reached important arms limitation agreements because it was seen then (as it is now) to be in their national security interest.

Trends: Launchers and Warheads

There are many uncertainties about the future development of Russian nuclear forces. Other than three aggregate numbers released under the New START Treaty, neither Russia nor the United States publish data on the numbers of Russian nuclear forces.

Russian officials occasionally make statements about the status of individual nuclear launchers and modernization programs, and Russian news articles provide additional background. Moreover, commercial satellite photos make it possible to monitor (to some extent) the status of strategic nuclear forces.

As a result, there is considerable – and growing – uncertainty about the status and trend of Russian nuclear forces. The available information indicates that Russia is continuing to reduce its strategic nuclear launchers well below the limit set by the New START Treaty. Over the next decade, all Soviet-era ICBMs (SS-18, SS-19, and SS-25) will be retired, the navy’s Delta III SSBN and its SS-N-18 missiles will be retired, and some of the Delta IV SSBNs will probably be retired as well.

To replace the Soviet-era launchers, Russia is deploying and developing several versions of the SS-27 ICBM and developing a new “heavy” ICBM. The navy is deploying the Borey-class SSBN with a new missile, the SS-N-32 (Bulava). This transition has been underway since 1997.

Depending on the extent of modernization plans over the next decade and how many missiles Russia can actually produce and deploy, the overall strategic force appears to be leveling off just below 500 launchers (see below), well below the New START Treaty limits of 700 deployed strategic launchers and 800 deployed and non-deployed strategic launchers.


 russia-launchers

The warhead loading on the strategic launchers is also decreasing mainly because of the retirement of warhead-heavy SS-18 and SS-19 ICBMs. But because single-warhead SS-25s are being replaced with MIRVed SS-27s, and because the navy’s new SS-N-32 (Bulava) missile carries more warheads than the SS-N-18 and SS-N-23 missiles it is replacing, the overall warhead loading appears to be leveling off as well (see below).

russia-warheads

Not all of these warheads are deployed on launchers at any given time. Weapons are not loaded on bombers under normal circumstances and some SSBNs and ICBMs are down for maintenance or repair. The latest New START Treaty warhead count was 1,582 warheads, which means approximately 1,525 warheads were on SSBNs and ICBMs (excluding the roughly 55 counted bombers that are artificially attributed one weapon each).

Non-strategic nuclear weapons are also described in the Notebook. Their status is even more uncertain than the strategic forces. We estimate there are roughly 2,000 warheads assigned to fighter-bombers, short-range ballistic missiles, naval cruise missiles and anti-submarine weapons, and land-based defense and missile-defense forces. Some of the non-strategic nuclear forces are also being modernized and the United States has accused Russia of developing a new ground-launched cruise missile in violation of the INF Treaty, but overall the size of the non-strategic nuclear forces will likely decreased over the next decade.

Russian Nuclear Strategy: What’s Real?

Underpinning these nuclear forces is Russia’s nuclear strategy, which reportedly is causing concern in NATO. A new study was discussed at the NATO ministerial meeting in February. “What worries us most in this strategy is the modernization of the Russian nuclear forces, the increase in the level of training of those forces and the possible combination between conventional actions and the use of nuclear forces, including possibly in the framework of a hybrid war,” one unnamed NATO official told Reuters.

That sounds like a summary of events over the past decade merged with fear that Putin’s currently military escapades could escalate into something more. The nuclear modernizations have been underway for a long time and the increased training is widely reported but its implications less clear. For all its concern about Russian nuclear strategy, NATO hasn’t said much in public about specific new developments.

A senior NATO official recently said Russia’s Zapad exercise in 2013 was “supposed to be a counter-terrorism exercise but it involved the (simulated) use of nuclear weapons.” In contrast, an earlier private analysis of Zapad-13 said the exercise included “virtually the entire range of conceivable military operations except for nuclear strikes…”

Russian nuclear strategy has been relatively consistent over the past decade. The most recent version, approved by Putin in December 2014, states that Russia “shall reserve for itself the right to employ nuclear weapons in response to the use against it and/or its allies of nuclear and other kinds of weapons of mass destruction, as well as in the case of aggression against the Russian Federation with use of conventional weapons when the state’s very existence has been threatened.”

This formulation is almost identical to the mission described in the 2010 version of the doctrine, which stated that Russia “reserves the right to utilize nuclear weapons in response to the utilization of nuclear and other types of weapons of mass destruction against it and (or) its allies, and also in the event of aggression against the Russian Federation involving the use of conventional weapons when the very existence of the state is under threat.”

Despite many rumors in both 2010 and 2014 that the strategy would incorporate preemptive nuclear strikes, neither document discusses such options (it is unknown what is in the secret versions). On the contrary, the nuclear portion of the strategy doesn’t seem that different from what NATO and the United States say about the role of their nuclear weapons: responding to use of weapons of mass destruction and even significant conventional attacks. The Russian strategy appears to limit the nuclear use in response to conventional attacks to when the “very existence” of Russia is threatened.

Given this defensive and somewhat restrictive nuclear strategy, why do we hear Russian officials throwing around nuclear threats against all sorts of scenarios that do not involve WMD attacks against Russia or threaten the very existence of the country?

For example, why does the Russian Ambassador to Denmark threaten nuclear strikes against Danish warships if they were equipped with radars that form part of the U.S. missile defense system when they would not constitute a WMD attack or threaten the existence of Russia?

Or why does President Putin say he would have considered placing nuclear weapons on alert if NATO had intervened to prevent annexation of the Crimean Peninsula if it were not an WMD attack or threaten the existence of Russia? (Note: Russia already has nuclear weapons on alert, although not in Crimea).

Or why did Russian officials tell U.S. officials that Russia would consider using nuclear weapons if NATO tries to force return of Crimea to Ukrainian control or deploys sizable forces to the Baltic States, if these acts do not involve WMD attacks or threaten the existence of Russia? (Kremlin denied its officials said that).

When officials from a nuclear-armed country make nuclear threats one obviously has to pay attention – especially if made by the president. But these nuclear threats so deviate from Russia’s public nuclear strategy that they are either blustering, or Russia has a very different nuclear strategy than its official documents portray.

Ironically, the more Russian officials throw around nuclear threats, the weaker Russia appears. Whereas NATO and the United States have been reluctant to refer to the role of nuclear weapons in the current crisis (despite what you might hear, the justification for U.S. non-strategic nuclear weapons in Europe is weaker today than it was before Russia’s invasion of Ukraine) and instead emphasized conventional forces and operations, Russia’s nuclear threats reveal that Russian officials do not believe their conventional forces are capable of defending Russia – even against conventional attack.

That makes it even stranger that Putin is wasting enormous sums of money on maintaining a large nuclear arsenal instead of focusing on modernizing Russia’s conventional forces, as well as using arms control to try to reduce NATO’s nuclear and conventional forces. That would actually improved Russia’s security.

New START Treaty Count: Russia Dips Below US Again

By Hans M. Kristensen

Russian deployed strategic warheads counted by the New START Treaty once again slipped below the U.S. force level, according to the latest fact sheet released by the State Department.

The so-called aggregate numbers show that Russia as of March 1, 2015 deployed 1,582 warheads on 515 strategic launchers.

The U.S. count was 1,597 warheads on 785 launchers.

Back in September 2014, the Russian warhead count for the first time in the treaty’s history moved above the U.S. warhead count. The event caused U.S. defense hawks to say it showed Russia was increasing it nuclear arsenal and blamed the Obama administration. Russian news media gloated Russia had achieved “parity” with the United States for the first time.

Of course, none of that was true. The ups and downs in the aggregate data counts are fluctuations caused by launchers moving in an out of overhaul and new types being deployed while old types are being retired. The fact is that both Russia and the United States are slowly – very slowly – reducing their deployed forces to meet the treaty limits by February 2018.

New START Count, Not Total Arsenals

And no, the New START data does not show the total nuclear arsenals of Russia and the United States, only the portion of them that is counted by the treaty.

While New START counts 1,582 Russian deployed strategic warheads, the country’s total warhead inventory is much higher: an estimated 7,500 warheads, of which 4,500 are in the military stockpile (the rest are awaiting dismantlement).

The United States is listed with 1,597 deployed strategic warheads, but actually possess an estimated 7,100 warheads, of which about 4,760 are in the military stockpile (the rest are awaiting dismantlement).

The two countries only have to make minor adjustments to their forces to meet the treaty limit of 1,550 deployed strategic warheads by February 2018.

Launcher Disparity

The launchers (ballistic missiles and heavy bombers) are a different matter. Russia has been far below the treaty limit of 700 deployed launchers since before the treaty entered into effect in 2011. Despite the nuclear “build-up” alleged by some, Russia is currently counted as deploying 515 launchers – 185 launchers below the treaty limit.

In other words, Russia doesn’t have to reduce any more launchers under New START. In fact, it could deploy an additional 185 nuclear missiles over the next three years and still be in compliance with the treaty.

The United States is counted as deploying 785 launchers, 270 more than Russia. The U.S. has a surplus in all three legs of its strategic triad: bombers, ICBMs, and SLBMs. To get down to the 700 launchers, the U.S. Air Force will have to destroy empty ICBM silos, dismantle nuclear equipment from excess B-52H bombers, and the U.S. Navy will reduce the number of launch tubes on each ballistic missile submarine from 24 to 20.

bangor071114

In 2015 the U.S. Navy will begin reducing the number of missile tubes from 24 to 20 on each SSBN, three of which are seen in this July 2014 photo at Kitsap Naval Submarine Base at Bangor (WA). The image also shows construction underway of a second Trident Refit Facility (coordinates: 47.7469°, -122.7291°). Click image for full size,

Even when the treaty enters into force in 2018, a considerable launcher disparity will remain. The United States plans to have the full 700 deployed launchers. Russia’s plans are less certain but appear to involve fewer than 500 deployed launchers.

Russia is compensating for this disparity by transitioning to a posture with a greater share of the ICBM force consisting of MIRVed missiles on mobile launchers. This is bad for strategic stability because a smaller force with more warheads on mobile launchers would have to deploy earlier in a crisis to survive. Russia has already begun to lengthen the time mobile ICBM units deploy away from their garrisons.

tagil070214

Modernization of mobile ICBM garrison base at Nizhniy Tagil in the Sverdlovsk province in Central Russia. The garrison is upgrading from SS-25 to SS-27 Mod 2 (RS-24) (coordinates: 58.2289°, 60.6773°). Click image for full size.

It seems obvious that the United States and Russia will have to do more to cut excess capacity and reduce disparity in their nuclear arsenals.

H-Bomb History Published Over Government Objections

Physicist Kenneth W. Ford, who participated in the design of the hydrogen bomb in the early 1950s, has published a memoir of his experiences despite the objections of Energy Department reviewers who requested substantial redactions in the text.

“Building the H Bomb: A Personal History” was released this month in softcopy by World Scientific Publishing Company. Hardcopy editions are to appear in May.

The dispute between the author and the government over the book’s publication was first reported by the New York Times in “Hydrogen Bomb Physicist’s Book Runs Afoul of Energy Department” by William J. Broad, March 23. The Times story immediately turned the book into something of a bestseller, and it ranks number one on Amazon.com in categories of Physics, Nuclear Physics, and Military Technology.

Significantly, Department of Energy reviewers did not attempt to compel the author to amend his text, nor did they seek to interfere with the book’s publication. So their response here is altogether different than in the 1979 Progressive case, when the government sought and received an injunction to block release of Howard Morland’s article “The H Bomb Secret.” Rather, they asked Dr. Ford to make extensive changes in his manuscript. Depending on one’s point of view, the requested changes may have been frivolous, unnecessary, or prudent. But there is no reason to suppose they were presented in bad faith. The Department had nothing to gain from its recommended changes.

For his part, Dr. Ford was not on a crusade to expose nuclear secrets. On the contrary, “I have bent every effort to avoid revealing any information that is still secret,” he wrote in prefatory remarks. As one of the original participants in the H-Bomb program, he has exceptional standing to render a judgment on what is and is not sensitive. “In my considered opinion, this book contains nothing whose dissemination could possibly harm the United States or help some other country seeking to design and build an H bomb.”

Still, while Dr. Ford’s scientific judgment is entitled to great weight, the question of what constitutes Restricted Data under the Atomic Energy Act is not a scientific issue. It is a legal matter which is delegated by statute to the Department of Energy. This means that DOE retains some legal authority over the information in the book which it has not yet used. One may still hope that the Department, in its wisdom, will decline to exercise that authority in this case.

“Building the H Bomb” is a rather charming and quite readable account of a young man finding his way in the midst of momentous scientific and political upheaval. It is not a history of the H-Bomb. For that, one still needs to turn to Richard Rhodes’ “Dark Sun” and other works. Dr. Ford does provide an introduction to the basic physics of nuclear weapons. But for those who don’t already know the names of John Wheeler (Ford’s mentor), Enrico Fermi, or Hans Bethe, and what made them great scientists and men of stature, this book will not enlighten them very much.

What the book does offer is an eyewitness account of several crucial episodes in the development of the hydrogen bomb. So, for example, Ford considers the contested origins of the Teller-Ulam idea that was the key conceptual breakthrough in the Bomb’s history. He cannot decisively resolve the disputed facts of the matter, but he knew Teller and he knew Ulam, as well as Richard Garwin, John Toll, Marshall Rosenbluth, David Bohm and many others, and he provides fresh perspectives on them and their activities. Any historian of the nuclear age will relish the book.

The National Security Archive has posted an informative commentary by Dr. Ford, along with several important declassified documents that were used by the author in preparing the book.

The INF Crisis: Bad Press and Nuclear Saber Rattling

By Hans M. Kristensen

Russian online news paper Vzglaid is carrying a story that wrongly claims that I have said a Russian flight-test of an INF missile would not be a violation of the INF Treaty as long as the missile is not in production or put into service.

That is of course wrong. I have not made such a statement, not least because it would be wrong. On the contrary, a test-launch of an INF missile would indeed be a violation of the INF Treaty, regardless of whether the missile is in production or deployed.

Meanwhile, US defense secretary Ashton Carter appears to confirm that the ground-launched cruise missile Russia allegedly test-launched in violation of the INF Treaty is a nuclear missile and threatens further escalation if it is deployed.

Background

The error appears to have been picked up by Vzglaid (and apparently also sputniknews.com, although I haven’t been able to find it yet) from an article that appeared in a Politico last Monday. Squeezed in between two quotes by me, the article carried the following paragraph: “And as long as Russia’s new missile is not deployed or in production, it technically has not violated the INF.” Politico did not explicitly attribute the statement to me, but Vzglaid took it one step further:

According to Hans Kristensen, a member of the Federation of American Scientists, from a technical point of view, even if the Russian side and tests a new missile, it is not a breach of the contract as long as it does not go into production and will not be put into service.

Again, I didn’t say that; nor did Politico say that I said that. Politico has since removed the paragraph from the article, which is available here.

The United States last year officially accused Russia of violating the INF Treaty by allegedly test-launching a ground-launched cruise missile (GLCM) to a range that violates the provisions of the treaty. Russia rejected the accusation and counter-accused the United States for violating the treaty (see also ACA’s analysis of the Russian claims).

Conventional or Nuclear GLCM?

The US government has not publicly provided details about the Russian missile, except saying that it is a GLCM, that it has been test-launched several times since 2008, and that it is not currently in production or deployed. But US officials insist they have provided enough information to the Russian government for it to know what missile they’re talking about.

US statements have so far, as far as I’m aware, not made clear whether the GLCM test-launched by Russia is conventional, nuclear, or dual-capable. It is widely assumed in the public debate that it concerns a nuclear missile, but the INF treaty bans any ground-launched missile, whether nuclear or conventional. So the alleged treaty violation could potentially concern a conventional missile.

However, in a written answer to advanced policy questions from lawmakers in preparation for his nomination hearing in February for the position of secretary of defense, Ashton Carter appeared to identify the Russian GLCM as a nuclear system:

Question: What does Russia’s INF violation suggest to you about the role of nuclear weapons in Russian national security strategy?

Carter: Russia’s INF Treaty violation is consistent with its strategy of relying on nuclear weapons to offset U.S. and NATO conventional superiority.

That explanation would imply that US/ NATO conventional superiority to some extent has triggered Russian development and test-launch of the new nuclear GLCM. China and the influence of the Russian military-industrial complex might also be factors, but Russian defense officials and strategists are generally paranoid about NATO and seem convinced it is a real and growing threat to Russia. Western officials will tell you that they would not want to invade Russia even if you paid them to do it; only a Russian attack on NATO territory or forces could potentially trigger US/NATO retaliation against Russian forces.

Possible Responses To A Nuclear GLCM?

The Obama administration is currently considering how to respond if Russia does not return to INF compliance but produces and deploys the new nuclear GLCM. Diplomacy and sanctions have priority for now, but military options are also being considered. According to Carter, they should be designed to “ensure that Russia does not gain a military advantage” from deploying an INF-prohibited system:

The range of options we should look at from the Defense Department could include active defenses to counter intermediate-range ground-launched cruise missiles; counterforce capabilities to prevent intermediate-range ground-launched cruise missile attacks; and countervailing strike capabilities to enhance U.S. or allied forces. U.S. responses must make clear to Russia that if it does not return to compliance our responses will make them less secure than they are today.

US Defense Secretary Ashton Carter

What to do? Defense Secretary Ashton Carter wants to use counterforce and countervailing planning if Russia deploys its new ground-launched nuclear cruise missile.

The answer does not explicitly imply that a response would necessarily involve developing and deploying nuclear cruises missiles in Europe. Doing so would signal intent to abandon the INF Treaty but the Obama administration wants to maintain the treaty. Yet the reference to using “counterforce capabilities to prevent” GLCM attacks and “countervailing strike capability to enhance U.S. or allied forces” sound very 1980’ish.

Counterforce is a strategy that focuses on holding at risk enemy military forces. Using it to “prevent” attack implies drawing up plans to use conventional or nuclear forces to destroy the GLCM before it could be used. Current US nuclear employment strategy already is focused on counterforce capabilities and does not rely on countervalue and minimum deterrence, according to the Defense Department. Given that a GLCM would be able to strike its target within an hour (depending on range), preempting launch would require time-compressed strike planning and high readiness of forces, which would further deepen Russian paranoia about NATO intensions.

“Countervailing” was a strategy developed by the Carter administration to improve the flexibility and efficiency of nuclear forces to control and prevail in a nuclear war against the Soviet Union. The strategy was embodied in Presidential Directive-59 from July 1980. PD-59 has since been replaced by other directives but elements of it are still very much alive in today’s nuclear planning. Enhancing the countervailing strike capability of US and NATO forces would imply further improving their ability to destroy targets inside Russia, which would further deepen Russian perception of a NATO threat.

Conclusions and Recommendations

Part of Carter’s language is probably intended to scare Russian officials into concluding that the cost to Russia of deploying the GLCM would be higher than the benefits of restoring INF compliance – a 21st century version of the NATO double-track decision in 1979 that threatened deployment of INF missiles in Europe unless the Soviet Union agreed to limits on such weapons.

Back then the threat didn’t work at first. The Soviet Union rejected limitations and NATO went ahead and deployed INF missiles in Europe. Only when public concern about nuclear war triggered huge demonstrations in Europe and the United States did Soviet and US leaders agree to the INF Treaty that eliminated those weapons.

Reawakening the INF spectra in Europe would undermine security for all. Both Russia and the United States have to be in compliance with their arms control obligations, but threatening counterforce and countervailing escalation at this point may be counterproductive. Vladimir Putin does not appear to be the kind of leader that responds well to threats. And the INF issue has now become so entangled in the larger East-West crisis over Ukraine that it’s hard to see why Putin would want to be seen to back down on INF even if he agreed treaty compliance is better for Russia.

In fact, the military blustering and posturing that now preoccupy Russia and NATO could deepen the INF crisis. Russia’s invasion of Ukraine and increased air operations across Europe fuel anxiety in NATO that leads to the very military buildup and modernization Russian officials say they are so concerned about. And NATO’s increased conventional operations and deployments in Eastern NATO countries probably deepen the Russian rationale that triggered development of the new GLCM in the first place.

Will Carter’s threat work? Right now it seems like one hell of a gamble.

This publication was made possible by a grant from the New Land Foundation and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.

JASON on the Physics of Nuclear Weapons

Despite the extensive data obtained through the conduct of more than 1000 nuclear explosive tests, there is still much that is unknown or imperfectly understood about the science of nuclear weapons.

A newly disclosed report prepared in 2011 by the JASON science advisory panel assessed efforts by the National Nuclear Security Administration (NNSA) to “develop improved understanding of the underlying physics of the materials and components in nuclear weapons.”

The study was released in redacted form last week in response to a Freedom of Information Act request from the Federation of American Scientists. See Hydrodynamic and Nuclear Experiments, JASON report JSR-11-340, November 2011.

More recently, JASON performed “a short study of the science and technology enabling improved measurement, characterization, and understanding of the state of stress in engineered subsurface systems of the Earth’s crust.” See Subsurface Characterization, Jason letter report JSR-14-Task-013, September 2014.

Seeking China-U.S. Strategic Nuclear Stability

“To destroy the other, you have to destroy part of yourself.

To deter the other, you have to deter yourself,” according to a Chinese nuclear strategy expert. During the week of February 9th, I had the privilege to travel to China where I heard this statement during the Ninth China-U.S. Dialogue on Strategic Nuclear Dynamics in Beijing. The Dialogue was jointly convened by the China Foundation for International Strategic Studies (CFISS) and the Pacific Forum Center for Strategic and International Studies (CSIS). While the statements by participants were not-for-attribution, I can state that the person quoted is a senior official with extensive experience in China’s strategic nuclear planning.

The main reason for my research travel was to work with Bruce MacDonald, FAS Adjunct Senior Fellow for National Security Technology, on a project examining the security implications of a possible Chinese deployment of strategic ballistic missile defense. We had discussions with more than a dozen Chinese nuclear strategists in Beijing and Shanghai; we will publish a full report on our findings and analysis this summer. FAS plans to continue further work on projects concerning China-U.S. strategic relations as well as understanding how our two countries can cooperate on the challenges of providing adequate healthy food, near-zero emission energy sources, and unpolluted air and water.

During the discussions, I was struck by the gap between American and Chinese perspectives. As indicated by the quote, Chinese strategic thinkers appear reluctant to want to use nuclear weapons and underscore the moral and psychological dimensions of nuclear strategy. Nonetheless, China’s leaders clearly perceive the need for such weapons for deterrence purposes. Perhaps the biggest gap in perception is that American nuclear strategists tend to remain skeptical about China’s policy of no-first-use (NFU) of nuclear weapons. By the NFU policy, China would not launch nuclear weapons first against the United States or any other state. Thus, China needs assurances that it would have enough nuclear weapons available to launch in a second retaliatory strike in the unlikely event of a nuclear attack by another state.

American experts are doubtful about NFU statements because during the Cold War the Soviet Union repeatedly stated that it had a NFU policy, but once the Cold War ended and access was obtained to the Soviets’ plans, the United States found out that the Soviets had lied. They had plans to use nuclear weapons first under certain circumstances. Today, given Russia’s relative conventional military inferiority compared to the United States, Moscow has openly declared that it has a first-use policy to deter massive conventional attack.

Can NFU be demonstrated? Some analysts have argued that China in its practice of keeping warheads de-mated or unattached from the missile delivery systems has in effect placed itself in a second strike posture. But the worry from the American side is that such a posture could change quickly and that as China has been modernizing its missile force from slow firing liquid-fueled rockets to quick firing solid-fueled rockets, it will be capable of shifting to a first-use policy if the security conditions dictate such a change.

The more I talked with Chinese experts in Beijing and Shanghai the more I felt that they are sincere about China’s NFU policy. A clearer and fuller exposition came from a leading expert in Shanghai who said that China has a two-pillar strategy. First, China believes in realism in that it has to take appropriate steps in a semi-anarchic geopolitical system to defend itself. It cannot rely on others for outside assistance or deterrence. Indeed, one of the major differences between China and the United States is that China is not part of a formal defense alliance pact such as the North Atlantic Treaty Organization (NATO) or the alliance the United States has with Japan and South Korea. Although in the 1950s, Chairman Mao Zedong decried nuclear weapons as “paper tigers,” he decided that the People’s Republic of China must acquire them given the threats China faced when U.S. General Douglas MacArthur suggested possible use of nuclear weapons against China during the Korean War. In October 1964, China detonated its first nuclear explosive device and at the same time declared its NFU policy.

The second pillar is based on morality. Chinese strategists understand the moral dilemma of nuclear deterrence. On the one hand, a nuclear-armed state has to show a credible willingness to launch nuclear weapons to deter the other’s launch.  But on the other hand, if deterrence fails, actually carrying out the threat condemns millions to die.  According to the Chinese nuclear expert, China would not retaliate immediately and instead would offer a peace deal to avert further escalation to more massive destruction. As long as China has an assured second strike, which might consist of only a handful of nuclear weapons that could hit the nuclear attacker’s territory, Beijing could wait hours to days before retaliating or not striking back in order to give adequate time for cooling off and stopping of hostilities.

Because China has not promised to provide extended nuclear deterrence to other states, Chinese leaders would also not feel compelled to strike back quickly to defend such states. In contrast, because of U.S. deterrence commitments to NATO, Japan, South Korea, and Australia, Washington would feel pressure to respond quickly if it or its allies are under nuclear attack. Indeed, at the Dialogue, Chinese experts often brought up the U.S. alliances and especially pointed to Japan as a concern, as Japan could use its relatively large stockpile of about nine metric tons of reactor-grade plutonium (which is still weapons-usable) to make nuclear explosives. Moreover, last July, the administration of Japanese Prime Minister Shinzo Abe announced a “reinterpretation” of the Article 9 restriction in the Japanese Constitution, which prohibits Japan from having an offensive military. (The United States imposed this restriction after the Second World War.)  The reinterpretation allows Japanese Self-Defense Forces to serve alongside allies during military actions. Beijing is opposed because then Japan is just one step away from further changing to a more aggressive policy that could permit Japan to act alone in taking military actions. Before and during the Second World War, Japanese military forces committed numerous atrocities against Chinese civilians. Chinese strategists fear that Japan is seeking to further break out of its restraints.

Thus, Chinese strategists want clarity about Japan’s intentions and want to know how the evolving U.S.-Japan alliance could affect Chinese interests. Japan and the United States have strong concerns about China’s growing assertive actions near the disputed Diaoyu Islands (Chinese name) or Senkaku Islands (Japanese name) between China and Japan, and competing claims for territory in the South China Sea. Regarding nuclear forces, some Chinese experts speculate about the conditions that could lead to Japan’s development of nuclear weapons. The need is clear for continuing dialogue on the triangular relationship among China, Japan, and the United States.

Several Chinese strategists perceive a disparity in U.S. nuclear policy toward China. They want to know if the United States will treat China as a major nuclear power to be deterred or as a big “rogue” state with nuclear weapons. U.S. experts have tried to assure their Chinese counterparts that the strategic reality is the former. The Chinese experts also see that the United States has more than ten times the number of deliverable nuclear weapons than China. But they hear from some conservative American experts that the United States fears that China might “sprint for parity” to match the U.S. nuclear arsenal if the United States further reduces down to 1,000 or somewhat fewer weapons.1 According to the FAS Nuclear Information Project, China is estimated to have about 250 warheads in its stockpile for delivery.2Chinese experts also hear from the Obama administration that it wants to someday achieve a nuclear-weapon-free world. The transition from where the world is today to that future is fraught with challenges: one of them being the mathematical fact that to get to zero or close to zero, nuclear-armed states will have to reach parity with each other eventually.

Reflections on the 70th Anniversary of the Manhattan Project: Questions and Answers

I began my professional life by obtaining degrees in physics and entering a conventional academic career in teaching and astronomical research, but I had always been curious about the physics of the Manhattan Project and its role in ending World War II. With grants, publications and tenure established, I began to indulge this interest as a legitimate part of my work and about 20 years ago, to explore it in depth.

As anybody that comes to this topic in more than a casual way will attest, it can grow into an obsession. I have now published two books on the Project, well over two dozen articles and book reviews in technical, historical, and semi-popular journals, and have made a number of presentations at professional conferences. Over this time I must have looked at thousands of archived documents and held hundreds of real and electronic conversations with other scientists, historians, and writers whose interest in this pivotal event parallels my own. While my knowledge of the Project is certainly not and never will be complete, I have learned much about it over the last 20 years.

To my surprise (and pleasure) I am frequently asked questions about the Project by students, family members, guests at dinner parties, colleagues at American Physical Society meetings, and even casual acquaintances at my favorite coffee shop. Typical queries are:

“Why did we drop the bombs? Were they necessary to end the war?”

“Did President Truman and his advisors really understand the power of the bombs and the destruction they could cause?”

“Have nuclear weapons helped deter subsequent large-scale wars, and do we still need a deterrent?”

“What about the ethical aspects?”

“In studying the Manhattan Project, what most surprised you? Do you think it or something similar could be done now?”

At first I was awkward in trying to answer these questions but with passing years, increased knowledge, and much reflection I now feel more comfortable addressing them. With accumulating experience in a scientific career, you often learn that the questions you and others initially thought to be important may not be the ones that the facts address and that there may be much more interesting issues behind the obvious ones. In this spirit, I offer in this essay some very personal reflections on the Project and the legacies of Hiroshima and Nagasaki, framed as responses to questions like those above. In some cases a “yes” or “no” along with an explanation will do, but for many issues the nuances involved obviate a simple response.

I begin with the issue of the “decision” to use the bomb and the state of President Truman’s knowledge. In the spring of 1945, Secretary of War Henry Stimson assembled a committee to consider and advise upon immediate and long-term aspects of atomic energy. This “Interim Committee” comprised eight civilians, including three scientists intimately familiar with the Manhattan Project: Vannevar Bush, James Conant, and Karl Compton. In a meeting on May 31 which was attended by Army Chief of Staff General George C. Marshall, Stimson opened with a statement as to how he viewed the significance of the Project1:

The Secretary expressed the view, a view shared by General Marshall, that this project should not be considered simply in terms of military weapons, but as a new relationship of man to the universe. This discovery might be compared to the discoveries of the Copernican theory and of the laws of gravity, but far more important than these in its effect on the lives of men. While the advances in the field to date had been fostered by the needs of war, it was important to realize that the implications of the project went far beyond the needs of the present war. It must be controlled if possible to make it an assurance of future peace rather than a menace to civilization.

For his part, President Truman had been thoroughly briefed on the project by Stimson and General Leslie Groves, director of the Project, soon after he became President in late April. In late July, Truman recorded his reaction to the Trinity test in his diary2:

We have discovered the most terrible bomb in the history of the world. … Anyway we think we have found the way to cause a disintegration of the atom. An experiment in the New Mexico desert was startling – to put it mildly. Thirteen pounds of the explosive caused the complete disintegration of a steel tower 60 feet high, created a crater 6 feet deep and 1,200 feet in diameter, knocked over a steel tower 1/2 mile away and knocked men down 10,000 yards away. The explosion was visible for more than 200 miles and audible for 40 miles and more. … The target will be a purely military one and we will issue a warning statement asking the Japs to surrender and save lives. I’m sure they will not do that, but we will have given them the chance. It is certainly a good thing for the world that Hitler’s crowd or Stalin’s did not discover this atomic bomb. It seems to be the most terrible thing ever discovered, but it can be made the most useful…

I have no doubt that Stimson, Marshall and Truman were well aware of the revolutionary nature of the bomb and the possibility (indeed, likelihood) that a postwar nuclear arms race would ensue. Any notion that Truman was a disengaged observer carried along by the momentum of events is hard to believe in view of the above comments. These men were making decisions of grave responsibility and were fully briefed as to both the immediate situation of the war and possible long-term geopolitical consequences: the “mature consideration” that Franklin Roosevelt and Winston Churchill agreed in 1943 would have to be carried out before use of the bombs was authorized. Perhaps Truman did not so much make a positive decision to use the bombs so much as he opted not to halt operations that were already moving along when he became President, but I have no doubt that he realized that atomic bombs would be a profoundly new type of weapon. Further, let us not forget that it was Truman who personally intervened after Nagasaki to order a halt to further atomic bombings when the Japanese began to signal a willingness to consider surrender negotiations.

As much as I am convinced that Truman took his duties with the greatest sense of responsibility, I cannot answer “yes” or “no” as to the necessity of the bombings: the question is always loaded with so many unstated perspectives. If the Japanese could not be convinced to surrender, then Truman, Stimson, and Marshall faced the prospect of committing hundreds of thousands of men to a horrific invasion followed by a likely even more horrific slog through the Japanese home islands. After 70 years it is easy to forget the context of the war in the summer of 1945. Historians know that the Japanese were seeking a path to honorable surrender and might have given up within a few weeks, but the very bloody fact on the ground was that they had not yet surrendered; thousands of Allied and Japanese servicemen were dying each week in the Pacific. Military historian Dennis Giangreco has studied Army and War Department manpower projections for the two-part invasion of Japan scheduled for late 1945 and the spring of 19463. Planning was based on having to sustain an average of 100,000 casualties per month from November 1945 through the fall of 1946. The invasion of Kyushu was scheduled to begin on November 1, 1945. Had this occurred, the number of casualties might well have exceeded the number of deaths at Hiroshima and Nagasaki, let alone those which would have occurred in the meantime. From the perspective of preventing casualties, perhaps it was unfortunate that the bombs were not ready at the time of the battle for Iwo Jima, one of the bloodiest protracted battles from February 19 to March 26, 1945, during which more than 25,000 were killed on both sides.

Even if they believe that the Soviet Union’s declaration of war on the night of August 8, 1945, against Japan was the most significant factor in the Japanese decision to surrender, most historians allow that the bombs had at least some effect on that decision. The Soviet invasion came between the two atomic bombings on August 6 (Hiroshima) and August 9 (Nagasaki). These two bombings would convince the Japanese that Hiroshima was not a one-shot deal: America could manufacture atomic bombs in quantity. The impact of the bombings was alluded to by Emperor Hirohito in his message to his people on August 15, 1945, in which he stated that “ … the enemy has begun to employ a new and most cruel bomb,” which was one of the motivations for his government’s decision to accept the terms of the Potsdam Declaration. But there are certainly political aspects that muddy this story, namely justifying the immense resources poured into the Project and sending a message to the Soviets that at least for a while America was the ascendant postwar power in the world. I give a qualified “yes” to the question of necessity.

The necessity debate often overlooks a corollary issue which I have come to think of as “nuclear inoculation.” Had the bombs not been used in 1945 and world leaders made aware of their frightening power, what far more awful circumstances might have unfolded in a later war when there were more nuclear powers armed with more powerful weapons? I am absolutely convinced that the bombings have had a significant deterrent effect and that they may well have prevented the outbreak of further major wars since 1945. Indeed, we know that there were occasions such as the Cuban missile crisis when national leaders looked into the maw of a possible large-scale war and backed away.

The “inoculation” issue leads to the question of whether or not America continues to need a nuclear deterrent. To this I say: “Yes, but for not entirely rational reasons.” Even very conservative military planners estimate that a few hundred warheads would be enough for any conceivable nuclear-mission scenario and that the thousands still stockpiled are a waste of resources and budgets. But the deterrent issue seems to me to be more psychological than mission-driven. With potentially unstable or irrationally-led states pursuing weapons and possibly encouraging proliferation, what “established” nuclear power would consider unilaterally disarming itself?  If America and Russia engage in further rounds of treaties and draw down their numbers of deployed and reserved weapons from thousands of warheads, a time may come when these numbers will get down to those held by powers such as Britain, France, China, India and Pakistan4. How then will negotiations proceed? Even if rigorous inspection regimes are agreed to, it seems to me that it will take decades until we might get to a level of trust where we won’t feel compelled to rationalize: “They could be slipping a few weapons into their arsenal under the table; we had better keep some in reserve.” In the meantime, I encourage students and acquaintances to question their elected representatives regarding the Comprehensive Test Ban Treaty and a possible Fissile Materials Cutoff Treaty.

What about the ethics of the bombings? To my mind the answer is: “The war had rendered this issue irrelevant.” Even against the “standards” of present-day terrorist acts, the ferocity of World War II seems almost incomprehensible. Deliberate atrocities against civilians and prisoners by the Axis powers were beyond the ethical pale, but how does one classify the Allied fire-bombings of Coventry, Dresden, and Tokyo even if there were arguable military objectives? The vast majority of victims at Hiroshima and Nagasaki succumbed not to radiation poisoning but to blast and burn effects just like the victims of these other attacks. I do not see that the bombs crossed an ethical threshold that had not already been breached many times before.

What have I learned about the Manhattan Project that especially surprised me? Well, practically everything. I approached the Project as a physicist, and it was a revelation for me that much of the physics involved is entirely accessible to a good undergraduate student. Computing critical mass involves separating a spherical-coordinates differential equation and applying a boundary condition: advanced calculus. Estimating the energy released by an exploding bomb core is a nice example of using the Newtonian work-energy theorem of freshman-level physics in combination with some pressure/energy thermodynamics. Appreciating how a calutron separates isotopes is a beautiful example of using the Lorentz force law of sophomore-level electromagnetism. Estimating the chance that a bomb might detonate prematurely due to a spontaneous fission invokes basic probability theory. These are exotic circumstances which require wickedly difficult engineering to realize, but the physics is really quite fundamental.

Everybody knows that the Manhattan Project was a big undertaking, but I now realize just how truly vast it was. At first, one’s attention is drawn to the outstanding personalities and dramatic events and locales associated the Project: J. Robert Oppenheimer, Enrico Fermi, Groves, Los Alamos, Trinity, Tinian, Hiroshima and Nagasaki. Then the  appreciation of the complexity of the production factories at Oak Ridge and Hanford, facilities designed by unappreciated and now largely-forgotten engineers of outstanding talent. Hundreds of contractors and university and government laboratories were involved, staffed by hundreds of thousands of dedicated employees. Also, bombs are not transported by magic to their targets; bombers had to be modified to carry them, and training of crews to fly the missions was initiated well before the final designs of the bombs and choice of targets were settled. The magnitude of the feed materials program to source and process uranium ores is rarely mentioned, but without this there would never have been any bombs (or any later Cold War).

While physics, chemistry, and engineering were front-and-center, I have also come to appreciate that the organization and administration of the Project was equally important. This is a hard thing for an academic scientist to admit! The Project was incredibly well-administered, and there is a lesson here for current times. Yes, the Project had its share of oversight and consultative committees, but they were run by scientists, engineers, government officials and military officers of superb competence and selfless dedication to the national good. These people knew what they were doing and knew how to get things done through the bureaucratic channels involved. An existential threat is always good for getting attention focused on a problem, but somebody has to actually do something. Of course there were security leaks and some inefficiencies, but what else would you expect in an undertaking so large and novel?

Could a Manhattan-type project be done now? I do not doubt for a moment that American scientists, technicians, engineers, and workers still possess the education, brains, dedication, and creativity that characterized Manhattan. But I do not think that such success could be repeated. Rather, headlines and breathless breaking news reports would trumpet waste, inefficiency, disorganization, technically clueless managers, and publicity-seeking politicians. The result would likely be a flawed product which ran far over-budget and delivered late if at all, no matter how intense the motivation. Do the words “Yucca Mountain” require further elaboration?

General Groves’ official history of the Project, the Manhattan District History, can be downloaded from a Department of Energy website, and I encourage readers to look at it5. It is literally thousands of pages, and is simply overwhelming; I doubt that anybody has read it from end-to-end. Click on any page and you will find some gem of information. Beyond the MDH lie thousands of secondary sources: books, popular and technical articles, websites and videos. But I have not one iota of regret that I plunged in. The Project was vast: many aspects of it have yet to be mined, and there are lessons to be had for scientists, engineers, biographers, historians, administrators, sociologists, and policy experts alike.

My research on the Project has made me much more aware of the world nuclear situation. Belief in deterrence aside, I am astonished that there has not been an accidental or intentional aggressive nuclear detonation over the last seventy years. We now know that on many occasions we came very close and that we have been very lucky indeed. While I see the chance of a deliberate nuclear-power-against-nuclear-power exchange as remote, the prospect of a terrorist-sponsored nuclear event does cause me no small amount of concern.

Nuclear energy is the quintessential double-edged sword, and those of us who have some understanding of the history, technicalities and current status of nuclear issues have a responsibility to share our knowledge with our fellow citizens in a thoughtful, responsible way. The stakes are no less existential now than they were seventy years ago.