BECAUSE OF THE INCOMPLETE NATURE OF AVAILABLE INFORMATION ON POTENTIAL NON-STATE NUCLEAR TERRORISTS, NO EXTRAPOLATION MAY BE MADE FROM THE MERE FACT THAT INCIDENTS OF NUCLEAR TERRORISM HAVE NOT OCCURRED. A REVIEW OF PAST TERRORIST ACTIVITIES, AND OF REVOLUTIONARY AND TERRORIST GROUPS REVEALS THAT 288 RECORDED THREATS OR INCIDENTS OF VIOLENCE IN THE UNITED STATES WERE DIRECTED AT NUCLEAR FACILTIES BETWEEN 1969 AND 1975. MOST OF THESE INCIDENTS WERE BOMB THREATS OR SUSPICIOUS FIRES. THE COMBINATION OF ANTINUCLEAR POLITICAL GROUPS AND OTHER EXTREMISTS HAS LED TO VIOLENCE IN EUROPE, BUT THERE IS NO EVIDENCE THAT ANY GROUP HAS ATTEMPTED TO ACQUIRE PLUTONIUM. BECAUSE THE NUMBER OF REACTORS WILL INCREASE, AND POLITICAL TRENDS INDICATE INCREASING VIOLENCE, THE PAST SAFETY OF FACILITIES DOES NOT INDICATE A CALM FUTURE. MOREOVER, IN MANY DEVELOPING NATIONS, INTERNAL COUPS AND INSURGENT MOVEMENTS MAY RESULT IN THE STRUGGLE FOR CONTROL OF REACTORS AND REPROCESSING PLANTS. SMALL GROUPS OF EXTREMISTS HAVE REPEATEDLY DEMONSTRATED THAT TERRORIST TACTICS CAN CREATE INTERNATIONAL INCIDENTS, AND THE PERPETRATORS DEMONSTRATE A WILLINGNESS TO USE ANY AVAILABLE WEAPONRY. NON-STATE ADVERSARIES COULD ARISE FROM ORGANIZATIONS AND SUBCLASSESS THAT HAVE NOT PREVIOUSLY BEEN RECOGNIZED, AS WELL AS FROM PROFIT-MINDED CRIMINALS, VIOLENT FOES OF THE MANUFACTURE OF NUCLEAR ARMS OR OF CIVILIAN NUCLEAR POWER PROGRAMS, DISGRUNTLED EMPLOYEES OF THE NUCLEAR INDUSTRY, AND INDIVIDUAL LUNATICS. SUCH GROUPS COULD RAPIDLY ACQUIRE DIVERTED WEAPONS AND NUCLEAR MATERIAL. THE SECURITY NECESSARY TO PROTECT THE ATOMIC INDUSTRY WOULD HAVE SERIOUS CIVIL LIBERTIES IMPLICATIONS. FOOTNOTES ARE PROVIDED. (TWK)