NRC Generic Letter 1983-32

NRC Generic Letter 1983-032: NRC Staff Recommendations Regarding Operator Action for Reactor Trip and ATWS

ML031080513
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Clinch River, Skagit, Marble Hill, Crane
Issue date:	12/02/1983
From:	Eisenhut D G Office of Nuclear Reactor Regulation
To:
References
GL-83-032, NUDOCS 8312020280
Download: ML031080513 (2)

?b 3...- .UNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D. C. 20555December 2, 1983TO ALL POWER REACTOR LICENSEES AND APPLICANTS FOR OPERATING LICENSESGentlemen:Subject: NRC Staff Recommendations Regarding Operator Action forReactor Trip and ATWS (Generic Letter 83-32)The NRC staff has developed the enclosed "Staff Position on OperatorActions for Reactor Trip and ATWS." The need for the development of aposition became apparent during discussions with several utilities as aresult of reactor trip failures. The attached position is being forwardedto you for information as it is being used within the staff for guidance.It does not constitute a requirement.ar> i Dr ctorDivision of LicensingOffice of Nuclear Reactor RegulationEnclosure: As stted8202284,54/ ,V.

I. -STAFF RECOMMENDATIONS ON OPERATOR ACTIONS FOR REACTOR TRIP AND ATWS(OCTOBER 1983)Operators have responsibilities and take some actions for all reactor trips.In the case of a failure of the automatic trip system, operator action is theonly backup to initiate rod insertion to shut down the reactor. Operatoraction to immediately back up all automatic trips with a manual trip basedsolely on receipt of "positive indication" of an "automatic trip demand"without evaluating the automatic trip system's success is believed by the NRCstaff to be conservative and, therefore, the preferred method. This operatoraction is not currently required by the NRC. Although not as conservative,another method is to have operators manually trip the reactor when thesuccessful completion of an automatic trip cannot be both immediately andpositively confirmed. With either method, if successful completion ofreactor trip cannot be immediately and positively confirmed after manual tripof the reactor, appropriate backup measures must be prescribed as part of theATWS emergency instructions.Facility procedures should identify the instruments that provide the"positive indication" of an "automatic trip demand." In addition, if thechoice is made to verify failure of the reactor trip system prior toinserting a manual trip, the procedures should identify the instruments thatprovide the "immediate and positive confirmation" of the success of theautomatic reactor trip. The instruments selected must provide timelyindications with adequate reliability to minimize the number of unnecessarymanual scrams and yet assure the operator is alerted to a system failure whenoperator action is necessary.