NRC: News Release - 2006-013 - NRC Staff Issues Generic Letter on Electric Grid Reliability Impact on Plant Risk

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NRC NEWS U.S. NUCLEAR REGULATORY COMMISSION
Office of Public Affairs	Telephone: 301/415-8200
Washington, DC 20555-0001	E-mail: opa@nrc.gov
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No. 06-013

February 2, 2006

NRC STAFF ISSUES GENERIC LETTER ON
ELECTRIC GRID RELIABILITY IMPACT ON PLANT RISK
Printable Version

The Nuclear Regulatory Commission staff has issued a Generic Letter asking all U.S. nuclear power plant operators for additional information on how they continue to ensure the reliability of offsite electrical power sources and how they continue to comply with NRC regulations on maintaining offsite power to safety-related systems.

The blackout of Aug. 14, 2003, caused nine U.S. nuclear power plants to shut down. Similar to non-nuclear facilities, when the grid is lost or significantly degraded, the protective circuits of the nuclear reactor and the turbine generator automatically shut down the plant to protect equipment. Nuclear facilities are designed with backup power sources, typically emergency diesel generators, to provide power to essential safety systems. During the blackout, diesel generators kept the nine plants in a safe condition.

The NRC’s review of the events surrounding the blackout raised several issues, including how plants prearrange for backup power from local sources and how they monitor the grid in real time. Plant operators have 60 days from the issuance of the Letter to submit written responses to questions in several areas, including:

– Arrangements between the plants and grid system operators or reliability coordinators, to monitor the grid’s ability to provide power to a plant’s safety systems;

– Arrangements for system operators to assist plants in considering grid conditions for assessing risks related to performing grid-risk sensitive maintenance; and,

– Procedures in place for identifying local power sources that could assist the plant when normal offsite power is unavailable.

A draft letter was published for comment in the Federal Register on April 12, 2005, and responses were incorporated into the final document. The NRC’s Advisory Committee on Reactor Safeguards reviewed the Generic Letter in November 2005. In January, the NRC staff also held a public meeting with nuclear power plant licensees, grid operators, the Federal Energy Regulatory Commission and other interested stakeholders to discuss the letter.

The Generic Letter will be available electronically on the NRC’s web site at this address: http://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/2006/index.html.