Failure to Participate in Turnover Contributes to Manual Reactor Head Vent Isolation Valves Being Left Open during Unit Startup

Significance: Sep 30, 2002 Identified By: NRC Item Type: FIN Finding UNEXPECTED CHANGES IN UNIT 2 OPERATING PARAMETERS AND DRYER FAILURE DUE TO FLOW INDUCED VIBRATION. The failure to consider the impact of new flow induced vibration failure mechanisms on the Unit 2 steam dryer as part of the extended power uprate analysis resulted in unexpected and unpredictable changes in reactor power, reactor vessel level, reactor pressure, and main steam line flow between June 7 and July 11, 2002. The licensee subsequently determined that the changes in Unit 2 operating parameters were caused by the failure of a Unit 2 steam dryer cover plate. This finding was more than minor because the changes in Unit 2 operating parameters caused by the degraded dryer created conditions which increased the likelihood of a plant transient. However, this finding was of very low risk significance because the changes in plant parameters and the dryer failure did not contribute to the likelihood of a primary or secondary loss of coolant accident initiator, did not contribute to the likelihood of a reactor trip with mitigating equipment not available, and did not increase the likelihood of a fire or an internal or external flood. There were no violations of NRC requirements due to the steam dryer being non-safety related. Inspection Report# : 2002007(pdf)