Backup Safety System Ball Replacement Program Physics Testing at the Hanford N Reactor

摘要

A series of measurements established the acceptability of B sub 4 C-carbon balls as a suitable replacement material for the Sm sub 2 O sub 3 -alumina balls in the N Reactor backup safety system. Out-of-reactor tests provided a measurement of the required boron loadings of the new balls, confirmed superior burnout characteristics, and verified significantly less material activation. The in-core testing measured the shutdown margins for the backup safety system with the B sub 4 C-carbon balls under normal and special failure conditions. As a result of the ball replacement program, improvements in safe operation and better radiological control should be achieved at the N Reactor. (ERA citation 05:022441)