Elements of importance for research in nuclear safety for upcoming decades – A personal perspective

Abstract

In this paper, a personal overview is presented of the potential research issues in nuclear safety in the upcoming decades, focussed on Light Water Reactors (LWRs) of Gen II and III types, plus a few words on Gen IV.As much experimental research so far was limited to small and intermediate scale, it is argued that often not sufficient insight in the scaling laws is present to apply the insights gained for the reactor case. Hence, the technical basis for a number of severe accident measures in present LWRs may need improvement. Where such shortcomings cannot be alleviated, it is recommended to apply engineered solutions. Dedicated I&C, capable of following the evolution of a severe accident, will be a substantial help for operators in accident management. Matters of long-term accident management should be considered. The Emergency Response Organisation should be capable of handling improvisations, if the accident evolution differs from the expected route. As a whole, nuclear industry should be better represented in the selection of relevant research issues.Regulation in severe accident matters has been somewhat expanded after the various severe accidents so far, but has basically remained the same. An important criterion should be the prevention of societal disruption, beyond the avoidance of fatalities. Also should the largely deterministic regulation be exchanged for a more probabilistic, risk-informed approach. These changes may result in the need to refurbish or even shutdown certain plants, for which the paper discusses some options for resolution.Some new Nuclear Power Plant projects have been plagued by large cost overruns. The paper discusses some causes and remedies.A series of new reactor designs have promising features, yet they often use unconventional materials. It is discussed, where it took the LWRs about 60 years to understand the chemistry of just water with conventional structural materials (e.g. steel), degradation mechanisms (corrosion, etc.) with all these unconventional materials must be studied, including long-time effects, to make them suitable for commercial application.Promising for the future is also the anticipated large advance in computer technology, which will open up new possibilities, both in analysis codes and plant operation, but will also bear some risk.To maintain the wealth of data obtained so far in experimental work, proper preservation of these data is needed. Improvement of existing data bases is suggested. Research levels should remain high, so as to foster innovation. Finally, although not an NPP safety issue, a caution is mentioned for the large spread of nuclear know-how over the world with the expanding number of countries building NPPs, as it may endanger the limitation of proliferation, as it exists today.