SYNTHESIS OF PHYSICAL SECURITY ASSESSMENT RESULTS

This paper describes two methods for combining observational data obtained from the physical security assessment team into a statement concerning the adequacy of the safeguards system at a nuclear fuel cycle facility. Because the data stem directly from the judgment of the assess- ment team members, both methods must cope with subjective estimates. To manage this the methods use concepts from decision analysis. The first uses a utility function, while the second adapts Bayes' theorem to meet the aggregation requirement. Sandia Laboratory and the firm of Woodward- Clyde Consultants developed the first method while the second was developed at the NRC. The underlying theme of the approach to the physical security assessment is analogous to the theme called \"divide and conquer\" described by Ward Edwards.1 The approach to assessing physical security, just as \"divide and conquer\" consists of three steps. Step 1: Divide the large problem along natural lines of separation into smaller pieces. Step 2: Make measurements or judgments on each small piece separately. Step 3: Combine together the measurements or judgments into the desired output.