Closeout of IE Bulletin 79-21: Temperature effects on level measurements

Technical Report · Sat Nov 01 04:00:00 EST 1986

OSTI ID:7144936

Dean, R S; Foley, W J; Hennick, A

On June 22, 1979, Westinghouse Electric Corporation reported to the NRC that elevated containment temperature could affect the reference leg water column and the indicated steam generator water level. IE Bulletin 79-21 was issued by the NRC on August 13, 1979 because of concern that the temperature effect could cause indication of erroneously high steam generator water levels, could delay or prevent protection signals and could cause incorrect information during post-accident monitoring. Because safety-related water level measuring systems used by Babcock and Wilcox and Combustion Engineering could be affected in the same way, the bulletin was issued for action to all utilities with operating pressurized water reactors (PWRS). The bulletin was issued for information to utilities with either PWRs under construction or operating boiling water reactors (BWRs). A related generic letter concerning BWRs was issued by the NRC in July 1979 for information only. Evaluation of licensees' responses and NRC/IE inspection reports shows that the bulletin can be closed out per specific criteria for all of the 41 facilities to which it was issued for action. It is concluded that utility responses were consistent because of guidance from the NSSS suppliers. Remaining areas of concern involve a possible need for manually deenergizing pressurizer heaters in B and W facilities, and further evaluation of boiling in the reference leg by Westinghouse.

• Research Organization: Parameter, Inc., Elm Grove, WI (USA)
• OSTI ID: 7144936
• Report Number(s): NUREG/CR-4522; ON: TI87900162
• Country of Publication: United States
• Language: English

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