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 Office of Nuclear Reactor Regulation
To:
References
GL-83-032, NUDOCS 8312020280
Download: ML031080513 (2)

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D. C. 20555 December 2, 1983 TO ALL POWER REACTOR LICENSEES AND APPLICANTS FOR OPERATING LICENSES

Gentlemen:

Subject: NRC Staff Recommendations Regarding Operator Action for Reactor Trip and ATWS (Generic Letter 83-32)

The NRC staff has developed the enclosed "Staff Position on Operator Actions for Reactor Trip and ATWS." The need for the development of a position became apparent during discussions with several utilities as a result of reactor trip failures. The attached position is being forwarded to you for information as it is being used within the staff for guidance.

It does not constitute a requirement.

ar> i Drctor Division of Licensing Office of Nuclear Reactor Regulation Enclosure: As stted

820228

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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 the only backup to initiate rod insertion to shut down the reactor. Operator action to immediately back up all automatic trips with a manual trip based solely on receipt of "positive indication" of an "automatic trip demand"

without evaluating the automatic trip system's success is believed by the NRC

staff to be conservative and, therefore, the preferred method. This operator action is not currently required by the NRC. Although not as conservative, another method is to have operators manually trip the reactor when the successful completion of an automatic trip cannot be both immediately and positively confirmed. With either method, if successful completion of reactor trip cannot be immediately and positively confirmed after manual trip of the reactor, appropriate backup measures must be prescribed as part of the ATWS emergency instructions.

Facility procedures should identify the instruments that provide the

"positive indication" of an "automatic trip demand." In addition, if the choice is made to verify failure of the reactor trip system prior to inserting a manual trip, the procedures should identify the instruments that provide the "immediate and positive confirmation" of the success of the automatic reactor trip. The instruments selected must provide timely indications with adequate reliability to minimize the number of unnecessary manual scrams and yet assure the operator is alerted to a system failure when operator action is necessary.