A Review of Gas-Cooled Reactor Concepts for SDI Applications

Abstract : We have completed a review of multimegawatt gas cooled reactor concepts proposed for SDI applications. Our study concluded that the principal reason for considering gas cooled reactors for burst mode operation was the potential for significant system mass savings over closed cycle systems if open cycle gas cooled operation (effluent exhausted to space) is acceptable. The principal reason for considering gas cooled reactors for steady state operation is that they may represent a lower technology risk than other approaches. In the review, nine gas cooled reactor concepts were compared to identify the most promising. For burst mode operation, the NERVA (Nuclear Engine for Rocket Vehicle Application) derivative reactor concept emerged as a strong first choice since its performance exceeds the anticipated operational requirements and the technology has been demonstrated and is retrievable. Although the NERVA derivative concepts were determined to be the lead candidates for the Multimegawatt Steady State (MMWSS) mode as well, their lead over the other candidates is not as great as for the burst mode.