Analysis of disassembling the radial reflector of a thermionic space nuclear reactor power system

An analysis was performed to investigate the effect of disassembling the radial reflector of the TOPAZ-II space nuclear reactor following a postulated reactivity initiated accident (RIA). In this RIA, the control drums, starting in the full-in position, are assumed to run out at their maximum speed of 1.4 degrees/s to their full-out position and remain out. This noncredible event occurs because of a malfunction in the drive mechanism of the control drums. Results indicate that the disassembly of only 3 of 12 radial reflector panels would successfully shut down the reactor with little overheating of the fuel and the moderator. 16 refs., 15 figs