THE RAPID GROWTH OF THE CIVILIAN NUCLEAR INDUSTRY, INCREASING TRAFFIC IN PLUTONIUM AND RADIOACTIVE MATERIALS AND WASTES, AND THE SPREAD OF NUCLEAR TECHNOLOGICAL KNOWLEDGE ALL INCREASE THE LIKELIHOOD THAT CRIMINALS OR TERRORISTS MIGHT ENGAGE IN SOME TYPE OF NUCLEAR ACTION. SUCH ACTION IS POSSIBLE; AN INDIVIDUAL OR GROUP OF INDIVIDUALS COULD CONCEIVABLY FABRICATE A CRUDE NUCLEAR WEAPON. THE BUILDING OF A NUCLEAR DISPERSAL DEVICE WOULD BE SOMEWHAT SIMPLER. THE MAIN OBSTACLE IN EITHER CASE IS THE ACQUISITION OF RADIOACTIVE MATERIALS. SABOTAGE OF AN EXISTING FACILITY IS ALSO POSSIBLE. AS OF 1977, A FEW INCIDENTS INVOLVING NUCLEAR REACTORS OR MATERIALS HAVE OCCURED, BUT THESE HAVE BEEN LOW-LEVEL -- VANDALISM AND MINOR THEFTS. WHILE THE ACTIVITIES OF TERRORISTS HAVE SHOWN INCREASINGLY GREATER IMAGINATION AND TECHNOLOGICAL SOPHISTICATION, THEY HAVE GENERALLY RELIED ON RELATIVELY SIMPLE WEAPONS OR TACTICS AND HAVE NOT USUALLY INVOLVED WELL-GUARDED TARGETS. IN ADDITION, IT IS DIFFICULT TO DETERMINE WHAT PURPOSE ACQUIRING A NUCLEAR CAPABILITY COULD SERVE GIVEN THE USUAL GOALS OF TERRORIST ACTION. SIMILARLY, IT IS DIFFICULT TO IMAGINE ORGANIZED CRIME DESIRING TO OBTAIN A NUCLEAR CAPABILITY, ALTHOUGH ITS INVOLVEMENT IN THE THEFT OR ILLEGAL TRAFFICKING IN NUCLEAR MATERIALS WOULD NOT BE UNLIKELY. FINALLY, PSYCHOTIC INDIVIDUALS OR SMALL GROUPS MIGHT, IN TERMS OF INTENTIONS ALONE, BE POTENTIAL NUCLEAR TERRORISTS, BUT THEY WOULD ALSO BE THE LEAST LIKELY TO POSSESS THE FINANCIAL MEANS AND THE TECHNOLOGICAL AND INTELLECTUAL SOPHISTICATION TO ACQUIRE A NUCLEAR CAPABILITY. WHILE IT IS AT PRESENT DIFFICULT TO IMAGINE NUCLEAR TERRORIST THREATS, IT IS POSSIBLE THAT NEW TYPES OF TERRORISTS MAY EMERGE -- FANATICAL OPPONENTS OF NUCLEAR TECHNOLOGY SEEKING TO PROVE A POINT OR A SCIENTIST WHO ALIGNS HIMSELF WITH SOME TERRORIST GROUP. POLITICAL OR SUCCESSFUL TERRORIST USE OF NUCLEAR DEVICES MAY ENCOURAGE IMITATION, PLUTONIUM COULD BECOME MORE EASILY AND WIDELY AVAILABLE, OR NEW TECHNOLOGY COULD MAKE PRODUCTION OF FISSIONABLE MATERIALS EASIER. AT SOME POINT IN THE FUTURE THE OPPORTUNITY AND CAPACITY FOR SERIOUS NUCLEAR VIOLENCE COULD REACH THOSE WILLING TO USE IT. (JAP)