HTGR: an assessment of safety and investment risk

Improvements in the present LWR designs which do not change the basic features that raise safety and economic concerns would not be expected to change public perception or be sufficient to encourage new nuclear investments by the utilities. The HTGR offers an attractive alternative, an alternative with proven operating experience and safety characteristics. This is demonstrated in this paper by an assessment of HTGR inherent safety features and by examining Fort St. Vrain operating experience data, which establish the HTGR as a forgiving design with respect to potential accidents. A further quantification of HTGR safety is made from a probabilistic risk assessment (PRA) of the 2240 MWt High-Temperature Gas-Cooled Reactor-Steam Cycle/Cogeneration (HTGR-SC/C) reference plant. These results are compared to NRC risk goals and achieved LWR safety. Finally, a proposed small HTGR reactor design is discussed. Although the relative costs and marketability of such a small reactor have yet to be determined, several additional passive safety characteristics of the small HTGR make such a plant essentially benign.