ML071510540

Commitment for Hydrogen Igniter Backup Power Supply & Closure Process for Generic Issue 189, Susceptibility of Ice Condenser & Mark III Containments to Early Failure from Hydrogen Combustion During a Severe Accident

ML071510540
Person / Time
Site:	Grand Gulf
Issue date:	06/15/2007
From:	Catherine Haney Plant Licensing Branch III-2
To:	Brian W Entergy Operations
Vaidya B, NRR/DORL/LP4, 415-3308
References
TAC MB7245
Download: ML071510540 (4)

Text

June 15, 2007 Mr. William R. Brian Vice President of Operations Grand Gulf Nuclear Station Entergy Operations, Inc.

P.O. Box 756 Port Gibson, MS 39150

SUBJECT:

GRAND GULF NUCLEAR STATION, UNIT 1 - COMMITMENT FOR HYDROGEN IGNITER BACKUP POWER SUPPLY AND CLOSURE PROCESS FOR GENERIC ISSUE 189, SUSCEPTIBILITY OF ICE CONDENSER AND MARK III CONTAINMENTS TO EARLY FAILURE FROM HYDROGEN COMBUSTION DURING A SEVERE ACCIDENT (TAC NO. MB7245)

Dear Mr. Brian:

This letter acknowledges your March 1, 2007, letter committing to changes at the Grand Gulf Nuclear Station that will enhance plant capabilities to mitigate the potential for early containment failure from hydrogen combustion. In addition to existing procedures to power one train of igniters through a cross-tie from the Division 3 diesel generator, you proposed changes involving procurement of portable equipment to power one train of igniters and development of associated procedures and training.

The Nuclear Regulatory Commission (NRC) staff agrees that the proposed changes will resolve concerns related to Generic Issue 189 (GI-189), Susceptibility of Ice Condenser and Mark III Containments to Early Failure from Hydrogen Combustion During a Severe Accident, and provide benefits for certain security scenarios. The NRC staff understands that the changes will enhance the electrical independence of the containment hydrogen igniter system. This action is warranted for boiling water reactors with Mark III containments because many systems that prevent core damage rely on the same power supplies and electrical distribution system as the hydrogen igniters. This enhancement mitigates the potential for early containment failure by allowing control of hydrogen within containment following certain beyond-design-basis events that may progress to core damage and preclude operation of the hydrogen igniters from their normal power supply. The NRC staff expects this enhancement will provide hydrogen igniter system electrical independence commensurate with the expected frequency, challenges, and uncertainties associated with these beyond-design-basis events.

Consistent with the guidelines of NRC Management Directive 6.4, Generic Issues Program, the NRC staff will perform a verification inspection at Grand Gulf. These inspections will include elements to verify that you establish procedures to provide back-up power to the hydrogen igniters, train appropriate staff in the procedures, and institute appropriate controls on the reliability and availability of necessary equipment. Procedures that allow trained personnel to establish backup power to the igniters within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> are fully consistent with goals to mitigate potential hydrogen accumulation. The NRC staff understands that implementation of vendor recommended maintenance and existing procedures will ensure adequate availability and

W. R. Brian reliability of the backup power supplies. In addition, NRC licensing project managers may verify the integrity of your commitments over time through established review procedures for your commitment management program.

Verification of your committed actions and those of other affected licensees will provide the basis by which the NRC will close out GI-189. The NRC staff will perform the verification inspection at a time consistent with the implementation date specified in your letter.

Accordingly, please keep the NRC staff informed of any changes in the scope of modifications or the implementation date.

Sincerely,

/RA by John Lubinski for Catherine Haney Catherine Haney, Director Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No.: 50-416 License No.: NPF-29 cc: See next page

ML071510540 OFFICE DSS/SBPB DSS/SBPB:BC DSS:D DPR/PGCB DIRS:D NAME SJones JSegala JWermiel JGolla ECollins DATE 6/5/07 6/5/07 6/5/07 6/5/07 6/8/07 OFFICE DORL/LPLIV/PM DORL/LPLIV/LA DORL/LPLIV/BC DORL/D NAME BVaidya JBurkhardt THiltz JWL for CHaney DATE 6/12/07 6/12/07 6/12/07 6/15/07 Grand Gulf Nuclear Station cc:

Mr. Michael L. Kansler, President and State Health Officer Chief Nuclear Officer State Board of Health Entergy Operations, Inc. P.O. Box 139 1340 Echelon Parkway Jackson, MS 39205 Jackson, MS 39213 Office of the Governor Executive Vice President State of Mississippi

& Chief Operating Officer Jackson, MS 39201 Entergy Operations, Inc.

P.O. Box 31995 Attorney General Jackson, MS 39286-1995 Asst. Attorney General State of Mississippi Chief P.O. Box 22947 Energy and Transportation Branch Jackson, MS 39225-2947 Environmental Compliance and Enforcement Division Vice President, Operations Support Mississippi Department of Environmental Entergy Operations, Inc.

Quality P.O. Box 31995 P.O. Box 10385 Jackson, MS 39286-1995 Jackson, MS 39289-0385 Director President Nuclear Safety Assurance Claiborne County Entergy Operations, Inc.

Board of Supervisors P.O. Box 756 P.O. Box 339 Port Gibson, MS 39150 Port Gibson, MS 39150 Director Regional Administrator, Region IV Nuclear Safety & Licensing U.S. Nuclear Regulatory Commission Entergy Operations, Inc.

611 Ryan Plaza Drive, Suite 400 1340 Echelon Parkway Arlington, TX 76011-8064 Jackson, MS 39213-8298 Senior Resident Inspector Manager, Licensing U.S. Nuclear Regulatory Commission Entergy Operations, Inc.

P.O. Box 399 P.O. Box 756 Port Gibson, MS 39150 Port Gibson, MS 39150 General Plant Manager Richard Penrod, Senior Environmental Operations Scientist/State Liaison Officer Entergy Operations, Inc. Office of Environmental Services P.O. Box 756 Northwestern State University Port Gibson, MS 39150 Russell Hall, Room 201 Natchitoches, LA 71497 Attorney General Department of Justice State of Louisiana P.O. Box 94005 Baton Rouge, LA 70804-9005 November 2006