The ORR operated at an average power level of 29.9 Mw for 84.9 percent of the time during October, November, and December of 1975. Eleven fuel elements were declared spent (52.5 percent average burnup) during the quarter, while twenty-nine new elements were placed in service. Four shim-rod elements were retired from service at an average burnup of 63 percent. The reactor was shut down on eight occasions, all of which were scheduled. Two end-of-cycle shutdowns accounted for 80.7 percent of the total downtime. The remaining downtime was used principally for refueling and experiment work. Maintenance activities, both mechanical and instrument, were essentially routine in nature. Special tests or measurements during the quarter included: (1) Flux mapping for core No. 129A; (2) Determination of minimum fuel content in ORR fuel elements prior to declaring the element spent; (3) Reactor vessel, ultrasonic test, and (4) Visual inspection of ORR primary pump.

The ORR operated at an average power level of 29.8 Mw for 87.2 percent of the time during July, August, and September of 1975. Twenty-eight fuel elements were declared spent (51.5 percent average burnup) during the quarter, while forty-two new elements were placed in service. Two shim-rod elements were retired from service at an average burnup of 65.5 percent. The reactor was shut down on eight occasions, one of which was unscheduled. One end-of-cycle shutdown accounted for 49.6 percent of the total downtime. A special shutdown to repair a water leak accounted for 40.6 percent of the total downtime. The remaining downtime was used principally for refueling, experiment work, and maintenance. Maintenance activities, both mechanical and instrument, were essentially routine in nature. All six shim rods were calibrated on August 18, 1975.

The ORR operated at an average power level of 29.0 MW for 80.9% of the time during October, November, and December of 1978. The reactor was shut down on fourteen occasions, four of which were unscheduled. Reactor downtime needed for refueling, maintenance and checks was normal, with the reactor remaining available for operation 92.2% of the time. Maintenance activities, both mechanical and instrument, were essentially routine in nature.