Role of research in the safety case of future reactor concepts definite needs, confirmatory areas, added value

In this paper, we aim to describe the role(s) of research when assessing - and finally demonstrating - the safety of future reactor concepts. The term 'research' could be defined in quite a limited fashion, while in this paper, we will use it synonymously to all Research and Design (R and D) work. First, we will provide a top-down planning perspective by identifying the general set of safety factors related to new reactor projects; i.e., factors that have to be accounted for already in the safety case. The research needs can be based on such a set of safety factors and related challenges, and it is crucial that the research requirements remain reasonable. For this, suitable design choices have to be made, such that they limit the criticality of individual plant functions, related systems/ structures/components (SSC), and human actions. In this context, we will discuss the general ways of limiting excessive research needs. The critical plant functions and SSC, in their turn, will require a strong safety demonstration. Once major design decisions have been made according to the aforementioned lines, actual systems are designed, using available equipment or developing new. Research support is needed to establish the technological adequacy and confidence level of each decision at each design level; this is relatively easy where conventional technologies are used, but more challenging if novel technologies come into question. Maturity of technology also correlates strongly with the attainable certainty and qualification of analysis tools. Here, we will describe the general phases of R and D from exploratory work to safety demonstration, and also independent confirmation. We will also touch upon the roles of different actors - the vendor, the licensee and the regulator - as well as their strategies in attacking the above-mentioned safety factors through research. (authors)