ASTR ROD-DRIVE REPLACEMENT.
Technical rept. 1 Oct 63-31 Dec 64,
GENERAL DYNAMICS/FORT WORTH TEX NUCLEAR AEROSPACE RESEARCH FACILITY
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The 10-Mw ASTR rod-drive mechanisms, originally designed for an airborne environment, were becoming difficult to repair because of high radiation levels and inability to procure directreplacement spare parts. Failure of the original mechanism is attributed to 1 misalignment, 2 component failure, 3 water damage, and 4 radiation damage. With the present reactor environment considerably different from that existing during the flight program, the mechanisms are no longer exposed to the g forces, extreme vibrations, and low temperatures for which they has been designed. However, the mechanisms are now required to function under varying depths of water of from 0 to 30 ft, under a core pressure of 75 psi, and at water temperatures of up to 185 F. Therefore, a program was initiated to develop a replacement drive mechanism. This program involved prototype design and fabrication, testing, and installation and checkout on the ASTR. The new rod-drive mechanism basically is a 115-v-60-cycle-powered rack and pinion type. The reactor operational checkout program resulted in several design changes being made in the mechanical interlock, shaft seals, electrical harness, and magnet-not-in-contact switch. These changes were incorporated in the nine mechanisms that were fabricated. The rod-drive mechanisms in their final configuration have performed well throughout reactor operation. Author