Letter to the Editor of The New York Times re Radkowsky Thorium Reactor-- not published. Richard L. Garwin Philip D. Reed Senior Fellow for Science and Technology Council on Foreign Relations 58 East 68th Street New York, NY 10021 (914) 945-2555 FAX: (914) 945-4419 INTERNET: RLG2 at watson.ibm.com June 2, 1998 (Via Email to letters at nytimes.com) Letters to the Editor The New York Times 229 West 43rd Street New York, NY 10036 Dear Editor: "Finding a Formula to Light the World but Guard the Bomb" (June 2) quotes the Radkowsky Thorium Power Corp. and commentators as stating that plutonium from the Radkowsky reactor core "could never produce more than a fizzle" if made into a nuclear weapon. At an explosive yield of 1000 or 2000 tons of explosive, compared with two tons of explosive in a truck bomb, and augmented by the nuclear radiation, a fizzle would level many city blocks. But the company and the commentators are wrong; this material can make a reliable bomb. In January 1997 the U.S. Department of Energy stated of reactor-grade plutonium, "Proliferating states using designs of intermediate sophistication could produce weapons with assured yields substantially higher than the kiloton-range possible with a simple, first-generation nuclear device." According to a 1997 publication by the Radkowsky company, plutonium extracted from the Radkowsky "seed" pellets would require about only 10% more material than normal reactor-grade plutonium to make a weapon and, that publication even states "A more sophisticated country might be able to design a weapon whose yield would be much less degraded by a spontaneous fission source." The heat from the plutonium core of such a weapon would amount to about 200 watts; a 200-watt light bulb would start a fire if buried under a pillow. But the problems of making a nuclear weapon with this plutonium containing 6% of the heat-generating isotope of plutonium (Pu-238) are not different in kind from those that must be met in making a weapon from military plutonium. Because of its utility in weapons, plutonium up to 80% Pu-238 must be protected in the same fashion as military plutonium, according to the International Atomic Energy Agency standards. As emphasized in a February 1998 study by the Royal Society of Britain, "The surest anti-proliferation measure is to stop reprocessing spent fuel and to reduce the quantity of separated plutonium in store." This would apply also to the Radkowsky approach. Sincerely yours, Richard L. Garwin The writer is Senior Fellow for Science and Technology at the Council on Foreign Relations and was an author of a 1995 National Academy of Sciences Report on Reactor Options for Disposition of Excess Weapon Plutonium RLG:jah:X153ENYT:060298ENYT Note to the Editor: I would be glad to send you by FAX the Radkowsky company publication in SCIENCE & GLOBAL SECURITY, 1997, vol. 6, pp. 265-290 (or at least the relevant pages) showing the relative critical masses that Radkowsky estimates for weapon-grade plutonium, normal reactor grade plutonium, the Radkowsky thorium reactor seed plutonium. These are 4.3 kilograms, 5.5 kilograms, and 5.9 kilograms.