Fort St. Vrain initial fuel loading and physics tests

The full-power operating license for the Fort St. Vrain Nuclear Generation Station was issued by the AEC on December 21, 1973. Core loading was started on December 27, 1973, and the loading of the 2274 fuel and reflector elements was completed in 20 days. Initial criticality was achieved on January 31, 1974. The critical control rod position indicated an 0.003 Δk difference between the predicted and actual critical core configuration. Pulsed-neutron measurements were performed to obtain the shutdown margin with all control rods inserted, the shutdown margin with the highest worth control rod pairs removed, and the reactivity worth of the control rod groups removed in the normal sequence in the approach to critical. Following the initial criticality, measurements of the axial flux distribution were performed in several regions of the core. The cold zero power measurements were performed with air in the core so that personnel access to the core cavity was possible to permit placement of in-core instrumentation. After completion of the cold physics measurements, the special in-core instrumentation was removed and the primary system was sealed and filled with helium. Measurements of reactivity coefficients are scheduled to be performed as part of the hot physics testing. Additional physics tests are scheduled for the rise-to-power test program and include measurements of control rod worth, temperature coefficient, xenon reactivity, and xenon stability