Safety case methodology for nuclear waste disposal - possible update considerations for Finnish usage

The report gives an introduction to the geological disposal of nuclear waste. In the licensing of nuclear waste disposal facilities, safety case is a widely used tool
for the safety demonstration. Safety case methodology is described briefly
touching e.g. its function and content. Three safety case references are
discussed briefly, namely IAEA, OECD NEA and Posiva versions. Safety assessment methodology for nuclear power plants have been improved along lessons learned from nuclear accidents, e.g. at Fukushima. Current discussion in Finland is based on defence-in-depth philosophy, top-down approach, and views about system of systems. A Fukushima-inspired topic is institutional strength-in-depth. The aim of this report is to discuss whether these topics need to be transferred to nuclear waste management as well. Analysing safety case methodology vis-à-vis the four previous topics indicates that in principle all of them are already covered in safety case. However, the desired extent and depth of organisational analysis may require wider discussion in nuclear waste community. In current safety cases organisational questions are mostly discussed in scenarios and in the description of licence applicant's management system.