Renewed interest in lead cooled fast reactors

In the last few years a number of compact designs of lead-alloy cooled systems have been promoted. Moreover, in Russia a design effort was started earlier on the pure lead-cooled BREST reactor but this effort does not appear to be strongly funded any more. But now the lead cooled and compact STAR-LM reactor is promoted in the US and in the European Union there is some interest in a mediumsized lead-cooled fast reactor (LFR). It has brought some nuclear industries, a large utility, several research centers and universities together to ask the European Commission for a partial funding of design and safety efforts. A 600 MWe LFR design is proposed which would be useful for base load operation but as a fast system it could also be used for load following. Because of the possible plant simplifications and the use of pure lead, the economics of such a system should be good. Moreover, efficient fuel utilization, the burning of higher actinides and a closed fuel cycle make it a sustainable system. Whether, this larger system has the same inherent / passive safety characteristics as smaller LFRs needs to be examined. In this paper the passive emergency decay heat removal by reactor vessel aircooling of such a larger system is investigated. Moreover an inlet blockage in a subassembly of a low power density LMR is analyzed. Furthermore, the pros and cons of lead vs. lead/bismuth coolants are discussed.