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.