Evaluating alternative design philosophies for spent nuclear fuel transport casks using a comparative probabilistic risk assessment approach

In this paper a PRA approach which uses comparison of alternative safety systems is proposed. The method assumes a linear risk model, and uses a selected probability function to compare the system of interest and an acceptable reference system. Features of the reference system may be varied to assess effects on system safety. The method is demonstrated by addressing effects of burnup credit on criticality control, an issue of current interest in the area of transport of radioactive materials. The example illustrates how the method measures effects of system changes, and how compensatory features can be introduced and assessed in terms of risk or reliability control