A probabilistic analysis of a catastrophic transuranic waste hoist accident at the WIPP

This report builds upon the extensive and careful analyses made by the DOE of the probability of failure of the waste hoist, and more particularly on the probability of failure of a major component, the hydraulic brake system. The extensive fault tree analysis prepared by the DOE was the starting point of the present report. A key element of this work is the use of probability distributions rather than so-called point estimates to describe the probability of failure of an element. One of the authors (MAG) developed the expressions for the probability of failure of the brake system. The second author (TJS) executed the calculations of the final expressions for failure probabilities. The authors hope that this work will be of use to the DOE in its evaluation of the safety of the waste hoist, a key element at the WIPP