Safety and environmental aspects of the Apollo-L2 D-3He reactor

Apollo-L2 is a D-³He fueled tokamak reactor design that utilizes direct conversion. The reactor shield is made of steel and cooled with water. Three different austenitic steel alloys (PCA, 316 55, and Tenelon) were chosen to study the impact of material selection on the environmental and safety attractiveness of the reactor. It was found that an Apollo-L2 Tenelon structure would qualify for Class A low level waste (LLW) and hence meet the US requirements for shallow land burial. Assuming heat conduction to the magnets the highest temperature an austenitic steel structure would reach following a loss-of-coolant accident is less than 500°C. However, conservative estimates for the early off-site dose were calculated based on experimental data for the volatilization of austenitic steel in dry air at temperatures ranging from 600°C to 1300°C. At 600°C, PCA and 316 SS would result in a whole-body early off-site dose less than 14 rem. The dose released from the Tenelon structure is about 30 mrem, requiring no public evacuation plans. The Apollo-L2 steel structure could qualify for a level of safety assurance of one