Year
1990
Abstract
The performance requirements of DOE Order 5633.3 (Materials Control and Accountability) specify that facilities which have custody of special nuclear material (SNM) should demonstrate that their protective systems achieve a designated level of performance in detecting the theft or diversion of SNM. The performance levels are defined in terms of a detection probability, a goal quantity of material, and a time to detection, depending upon the category and attractiveness of the material. In a typical facility there are approximately 25 individual elements of the system which contribute detection capability; the methods of vulnerability assessment are employed to combine the detection probabilities of those elements which enter into a given removal scenario to obtain an overall detection probability for the scenario. The central problem in this process is the quantitative determination of a valid detection probability for each element of the system for all relevant conditions. This requires the thorough evaluation of both the physical and procedural attributes of each element. Facility operating conditions (normal operations, off-shift, maintenance, and emergencies), the capabilities of a potential adversary (knowledge, access, authority, etc.), and possible failures of the element (breakdown, human error, etc.) may all enter into this determination. In addition, strategies available to the adversary for the defeat of a given element must be considered. The combined metal detector-SNM portal monitor element is discussed as an example of the evaluation process.