Application of EMCAS timeliness model to the safeguards/facility interface

The Hanford operating contractor has developed a timeliness model for periodic mass balance tests (MBTs) for loss of special nuclear material (SNM). The purpose of the model is to compute the probability that an adversary will be detected by a periodic MBT before he could escape from a facility with stolen SNM using stealth and deceit to avoid detection. The model considers (a) the loss detection sensitivity of the MBT, (b) the time between MBTs, and (c) the statistical distribution of the total time required to complete stealth and deceit strategies. The model shows whether or not it is cost-effective to conduct frequent MBTs for loss and where improvements should be made. The Evaluation Methods for Material Control and Accountability Safeguards Systems (EMCAS) timeliness model computes the loss detection capability of periodic materials control and accounting (MC ampersand A) tests in terms of (a) the ability of the test to detect the specified target quantity and (b) the probability that the MC ampersand A test will occur before the adversary can complete the sequence of stealth and deceit strategies required to avoid detection