Neutronics performance characteristics of the high power density evolve first wall/blanket system

The neutronics performance of the EVOLVE concept was analyzed using two-dim ensional calculations. The vapor fraction in the boiling blanket has a smal l impact on the nuclear performance parameters. For the worst case conditio n with the highest predicted vapor fraction distribution, all nuclear perfo rmance parameters are acceptable with a comfortable margin. The EVOLVE boil ing blanket is expected to perform adequately from the neutronics point of view for any of the boiling regimes considered. Analysis was performed also for a preliminary design of the transpiration blanket option indicating th at it will also have adequate nuclear performance parameters.