Safety/licensing assessment of the 2240-MW(t) HTGR steam cycle/cogeneration plant

This report discusses safety and licensing considerations for a steam cycle/cogeneration (SC/C) application of the high-temperature gas-cooled reactor (HTGR). The design is based on a 2240-MW(t) nuclear steam supply system (NSSS) that produces a nominal 300 MW(e) and 635 x 10/sup 6/ kg/m/sup 3/ (5.3 x 10/sup 6/ lb/hr) of high-quality steam for the process. This report describes inherent and engineered features that contribute to HTGR safety. It reviews the principal safety/licensing regulatory criteria and a number of issues that require data development or research activities. This report presents a radiological safety assessment of the HTGR-SC/C plant for normal operations and accidents. Design features and design criteria ensure maintenance of low risk to plant operators and the public and small releases of radioactivity to the environment. This report discusses accidents in terms of the conventional, conservative analyses required in safety analysis reports and from the standpoint of probabilistic risk assessment. Offsite dose consequences of the most severe design basis accident are small compared to regulatory guidance, and the risk due to very-low-probability core heatup accidents are small.