FAS

Some New Wrinkles in Nuclear Weapons Secrecy

08.22.11 | 2 min read | Text by Steven Aftergood

A newly released intelligence guide to document classification markings explains the meaning and proper use of control markings to designate classified information.  See “Authorized Classification and Control Markings Register” (pdf), CAPCO, Volume 4, Edition 2, May 31, 2011.  (See also the associated Implementation Manual of the same date.)

This material is very detailed, comprehensive and quite informative, with only a few redacted passages pertaining to some code word usages.

But though it is only three months old, it is already out of date due to the constant churning within the classification system that regularly generates new marking requirements and cancels old, familiar ones.  This has been particularly true lately with respect to changes in markings for “Restricted Data,” or classified nuclear weapons information.

Thus, the intelligence guide to classification marking refers to the so-called “Sigma” system for marking Restricted Data.  Each Sigma level refers to a particular aspect of nuclear weapons design.  According to the intelligence community guide, the Sigma system extends from Sigma 1 to Sigma 15 and also Sigma 20.  But that is no longer accurate.

In a July 2011 order (pdf), the Department of Energy determined that Sigma levels 1 through 5 and 9 through 13 are now obsolete.  So they have been disestablished.  Meanwhile, a new Sigma category, Sigma 18, has been created to address “Control of Complete Designs” and to protect “past and present U.S. nuclear weapons, nuclear devices and weapon designs.”  See “Control of Nuclear Weapon Data,” DoE Order 452.8, July 21, 2011.

At this late date in the nuclear era, there are still other “innovations” in nuclear technology and nuclear secrecy.  The New York Times reported last weekend on an apparent breakthrough in the use of lasers to enrich uranium.  This laser enrichment process, known as SILEX (Separation of Isotopes by Laser Excitation), also poses new proliferation issues.  See “Laser Advances in Nuclear Fuel Stir Terror Fear” by William J. Broad, August 21.

Though the Times story did not mention it, the SILEX process is also a unique case in which information that was privately generated was nevertheless classified by the government.  As far as could be determined, the decision to classify this non-governmental information under the Atomic Energy Act is the first and only time that such authority has been exercised.  [Update, August 25: This is not correct. See A Correction on Nuclear Secrecy.] See this 2001 “Record of Decision to Classify Certain Elements of the SILEX Process as Privately Generated Restricted Data.”  (See also “A Glimpse of the SILEX Uranium Enrichment Process,” Secrecy News, August 22, 2007.)

For its part, the Department of Defense issued a new Instruction last week on “Disclosure of Atomic Information to Foreign Governments and Regional Defense Organizations” (DoDI 5030.14, August 17, 2011).

publications
See all publications
FAS
Article
Scaling Team Science is the Important Experiment We Need

X-Labs seek to expand on what FROs have shown is possible: the generation of foundational infrastructure for entire new fields of research science.

07.14.26 | 6 min read
read more
Government Capacity
Blog
An open letter to the new NYC PIT Crew

This is a tremendous opportunity to redefine what people expect from government, and in doing so, inspire cities across the country to raise their own ambitions. We are excited to see this initiative lead the way and look forward to cheering your success.

07.13.26 | 3 min read
read more
Government Capacity
Policy Memo
We Need a U.S. Permitting Corps: Executive and Legislative Recommendations

Despite significant political momentum behind reform efforts, limited attention has been paid to the federal workforce that will actually be responsible for interpreting and implementing new permitting regulations and better outcomes.

07.08.26 | 10 min read
read more
Environment
Press release
Amid Sweltering Weather, the Federation of American Scientists Releases Expert-Sourced “State and Local Heat Policy Agenda”

Nearly 150 organizations and government officials have endorsed the call to action and solutions for extreme heat, now public at HeatAgenda.US Washington, D.C. – July 7, 2026 – As millions of Americans continue to struggle to stay cool following one of the hottest Independence Day holidays on record, the Federation of American Scientists (FAS), one […]

07.07.26 | 3 min read
read more