SAFETY ANALYSIS FOR SOMBRERO - A KRF LASER DRIVEN IFE REACTOR

Activation and safety analysis has been performed for the chamber, shield and Li2O coolant of the inertial confinement fusion (IFE) reactor SOMBRERO. The total activities generated in the reactor graphite chamber and steel-reinforced concrete shield at shutdown are 0.054 and 10.12 MCi, respectively. The biological dose rate at the back of the shield drops to 1.6 mrem/hr after one day of shutdown allowing for hands-on maintenance. Radwaste classification has shown that both the chamber and shield would easily qualify as Class A low level waste (LLW) according to the 10CFR61 waste disposal concentration limits (WDL). At the same time, the Li2O granules would qualify as Class C LLW. The maximum public dose from atmospheric effluents is 0.93 mrem/yr. The dose is due to tritium and its maximum value occurs at the reactor site boundary which is 1 km away from the point of tritium release. Only a small fraction (0.44%) of the graphite first wall would be mobilized during a loss of coolant accident (LOCA). During such an accident, the shield temperature would only increase by a few degrees releasing a very small fraction of its radioactive inventory. The total tritium inventory in the containment building which is assumed to be released at the onset of a severe accident is 182.6 grams. The estimated whole body (WB) early dose from a severe accident resulting in the failure of the reactor containment is 2.22 rem. The very low off-site dose eliminates the need for N-stamp nuclear grade components in SOMBRERO.