[en] It is a major advantage to those that must make decisions about the implementation of an emergency plan following an accident at a nuclear power plant if the likely release of activity is predicted before it occurs. To this end, a software module, which provides a rapid estimate of the source term to the environment, has been developed by NNC Ltd. Termed the RODOS STM, the software has been developed such that it can be used with the RODOS system. Operating outside of RODOS, the software remains a useful source term prediction tool. The software employs Bayesian analysis techniques, and the results of level 1 and level 2 probabilistic safety analysis, to calculate the probability of the possible releases of activity into the environment and the potential magnitude of those releases, given a set of observations about the status of the NPP. The software has been developed using the Sizewell 'B' PWR design. (author)

[en] Current regulation in the UK and elsewhere specify upper and target risk limits for the operation of nuclear plant in terms of frequencies of various kinds of accidents and accidental releases per annum. 'As low as reasonably practicable' (ALARP) arguments are used to justify the acceptance or rejection of policies that lead to risk changes between these limits. We assess the suitability of cost-benefit analysis (CBA) and multi-attribute utility theory (MAUT) for performing ALARP ('as low as reasonably possible') assessments, in particular within the nuclear industry. Four problems stand out in current CBA applications to ALARP, concerning the determination of prices of safety gains or detriments, the valuation of group and individual risk, calculations using 'disproportionality', and the use of discounting to trade off risks through time. This last point has received less attention in the past but is important because of the growing interest in risk-informed regulation in which policies extend over several timeframes and distribute the risk unevenly over these, or in policies that lead to a non-uniform risk within a single timeframe (such as maintenance policies). We discuss the problems associated with giving quantitative support to such decisions. We argue that multi-attribute utility methods (MAUT) provide an alternative methodology to CBA which enable the four problems described above to be addressed in a more satisfactory way. Through sensitivity analysis MAUT can address the perceptions of all stakeholder groups, facilitating constructive discussion and elucidating the key points of disagreement. We also argue that by being explicitly subjective it provides an open, auditable and clear analysis in contrast to the illusory objectivity of CBA. CBA seeks to justify a decision by using a common basis for weights (prices), while MAUT recognizes that different parties may want to give different valuations. It then allows the analyst to explore the ways in which different parties might (or might not) come to the same conclusion even when weighting items differently. (author)

[en] To understand barriers and enablers to use of curative-intent radiotherapy (RT) for muscle-invasive bladder cancer using the Theoretical Domains Framework (TDF).