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Title: Evaluation of events involving decay-heat-removal systems in nuclear power plants. [PWR; BWR]

Technical Report ·
OSTI ID:5138590

This report reviews and evaluates events placed in the NSIC file involving the removal of decay heat in US commercial boiling- and pressurized-water reactors from June 1979 through June 1981. The information was collected from operating experiences, licensee event reports, system designs in safety analysis reports, and other regulatory documents. The results were collated and analyzed according to safety significance and cause of event. Thirty-eight reported events in these 2.1 years meet the criteria for safety significance. Steam bubble formation in the reactor vessel head during natural circulation cooldown at St. Lucie 1 was the most significant event; operator awareness of the possibility of this occurrence and preparedness for dealing with it was the most important recommendation. Cavitation of residual heat removal pumps during decay heat removal operation was the most common potentially significant event. Davis-Besse 1 had several instances in which an inadvertent signal to the safety features actuation system caused the operating residual heat removal pumps to align to the dry sump causing pump cavitation.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5138590
Report Number(s):
NUREG/CR-2799; ORNL/NSIC-209; ON: DE82020131
Country of Publication:
United States
Language:
English