Year
1988
Abstract
We have developed a cost-benefit-risk methodology for evaluating material-accounting upgrades at key measurement points in nuclear facilities. The focus of this methodology is on nuclear-material measurements and their effects on inventory differences and shipper/receiver differences. The methodology has three main components: (1) Cost. This is the easiest factor to quantify; the cost is simply the present dollar cost of the upgrade, plus incremental operating and maintenance costs discounted as appropriate. (E) Benefits. The primary benefits of improved measurements are improved inventory differences (IDs) for material balance areas (MBAs) or improved shipper/receiver (S/R) differences. These can be quantified in terms of decreases in long-term cumulative gain and loss trends, which are related to the average (mean) ID or S/R difference, or decreases in the variability, which is related to the ID standard deviation. Not all forms of nuclear material are equally attractive targets for diversion, and the benefits for improving accountancy-system performance in MBAs containing high-grade material such as pure plutonium oxide should be greater than in those containing, for example, natural uranium. Weights are proposed to make such distinctions. (3) Risk factors. Two \"risk factors\" were identified as useful to include within the cost-benefit framework: the possibility that the upgrade would not perform as anticipated and the possibility thatproduction would be adversely affected by the upgrade. Both of these factors are hard to quantify, so judgemental values are employed. The fundamental outcome of the methodology is therefore cost-benefit ratios characterizing the proposed upgrades, with the risk factors applied as necessary to the benefits. Examples illustrate the methodology's use.