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At 1046 hours on August 19, 2011, Susqueha … At 1046 hours on August 19, 2011, Susquehanna Steam Electric Station Unit 2 reactor scrammed while (operators were) performing a quarterly functional test of reactor water high level trip channels for feedwater / main turbine. The main turbine tripped when a single channel high reactor water level signal was inserted, which was unexpected. Actual water level was within the normal band when the main turbine tripped. The main turbine trip resulted in a reactor scram. Reactor recirculation pump trips as designed and all control rods inserted. Reactor water level lowered to +2 inches causing Level 3 (+ 13 inches) isolations. Reactor water level was restored to the normal operating band using the feedwater system. Six main steam relief valves opened for a short duration, as expected, due to the turbine trip transient. Subsequently, reactor pressure was controlled via turbine bypass valve operation. All safety systems operated as expected. No ECCS or RCIC initiations occurred or were required.</br>The reactor recirculation pumps were subsequently restarted to re-establish forced core circulation.</br>The reactor is currently stable in Mode 3. An investigation into the cause of the scram is underway.</br>Unit 1 was unaffected and continued power operation.</br>The NRC Resident Inspector was notified. A press release will occur. was notified. A press release will occur. +
14:46:00, 19 August 2011 +
47,172 +
14:06:00, 19 August 2011 +
14:46:00, 19 August 2011 +
At 1046 hours on August 19, 2011, Susqueha … At 1046 hours on August 19, 2011, Susquehanna Steam Electric Station Unit 2 reactor scrammed while (operators were) performing a quarterly functional test of reactor water high level trip channels for feedwater / main turbine. The main turbine tripped when a single channel high reactor water level signal was inserted, which was unexpected. Actual water level was within the normal band when the main turbine tripped. The main turbine trip resulted in a reactor scram. Reactor recirculation pump trips as designed and all control rods inserted. Reactor water level lowered to +2 inches causing Level 3 (+ 13 inches) isolations. Reactor water level was restored to the normal operating band using the feedwater system. Six main steam relief valves opened for a short duration, as expected, due to the turbine trip transient. Subsequently, reactor pressure was controlled via turbine bypass valve operation. All safety systems operated as expected. No ECCS or RCIC initiations occurred or were required.</br>The reactor recirculation pumps were subsequently restarted to re-establish forced core circulation.</br>The reactor is currently stable in Mode 3. An investigation into the cause of the scram is underway.</br>Unit 1 was unaffected and continued power operation.</br>The NRC Resident Inspector was notified. A press release will occur. was notified. A press release will occur. +
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