ML20043H121

Application for Amends to Licenses NPF-4 & NPF-7,enhancing RHR Reliability by Allowing for Reduced RCS Circulation Flow to Reduce Vortex Formation & Air Ingestion Into RHR Pumps

ML20043H121
Person / Time
Site:	North Anna
Issue date:	06/13/1990
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20043H122	List: ML20043H121 ML20043H124
References
90-340A, GL-87-12, GL-88-17, NUDOCS 9006220034
Download: ML20043H121 (3)

Text

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'o q.' E VIRGINIA ELFCTRIC AND power COMPANY RICHMOND, VIRGINIA 23261 June 13,1990 U. S. Nuclear Regulatory Commission Serial No. 90 340A Attention: Document Control Desk NOS/TAH/KDT  !

Washington, D. C. 20555 Docket Nos. 50 338 50 339 l License Nos. NPF 4 ,

NPF-7 I Gentlemen:

i VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 l PROPOSED TECHNICAL SPECIFICATION CHANGES RESIDUAL HEAT REMOVAL (RHR) SYSTEM - RESUBMITTAL On June 8,1990, we submitted a proposed Technical Specification change (Serial No.

90 340) to enhance RHR system reliability by permitting reduced minimum RCS circulation flow under certain conditions, in that letter we failed to include the affected '

Bases pages. For convenience, we are resubmitting the entire proposed change, including the Bases pages. This letter suporsedes our June 8,1990 request.

Pursuant to 10 CFR 50.90, Virginia Electric and Power Company requests an amendment in the form of changes to the Technical Specifications (T.S.) of the Operating Licenses s Nos. NPF-4 and NPF 7 for North Anna Power Station Units 1 and 2, respectively.

These changes will enhance RHR reliability by allowing for a reduced RCS circulation flow thereby reducing vortex formation and air ingestion into the RHR pumps while ,

operating in a reduced RCS inventory condition . This problem has been addressed  !

specifically as being a major contributor to Loss of Decay Heat Removal events in Generic  :

Letters 87-12 and 8817. l North Anna Unit 1. Technical Specifications require a minimum RCS flow of 3000 gpm while performing reductions in RCS boron concentrations. Although there is no Technical <

Specification requiring this in the Unit 2 Technical Specifications, it is addressed in the Basis for the Reactor Coolant Section. This change will add a specification to the Unit 2 Technical Specifications, identical to the Unit 1 specification, requiring 3000 gpm RCS flow during boron concentration reductions thus ensuring that even though a lower RHR flow rate may be allowed, adequate RHR flow will be explicitly required for uniform mixing of the RCS,  ;

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• Technical Specifications list various requirements for RHR OPERABILITY in several different specifications. This has caused confusion as to which criteria should be applied '

for given situations. This change provides for more uniform OPERABILITY determination by referring RHR OPERABILITY requirements specified in the

• Reactor Coolant System" section of the Technical Specifications to the

• Plant Systems" RHR specifications 4.7.9.2.

The proposed changes are provided in Attachment 1 for the current Technical Specifications. The discussions, safety evaluations and the No Significant Hazards Determinations for these changes are enclosed in Attachment 2. These proposed changes do not affect the MERITS Technical Specifications previously submitted and currently under review.

These requests have been reviewed and approved by the Station Nuclear Safety and Operating Committee, it has been determined that the proposed changes do not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92.

Very truly yours,

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W. L. STEWART Senior Vice President Nuclear Attachments

1. Proposed Technical Specification. Changes

2. Discussion, Safety Evaluation and Significant Hazards Determinations cc: U. S. Nuclear Regulatory Commission 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Lesser NRC Senior Resident inspector North Anna Power Station Commissioner Department of Health Room 400 109 Governor Street l

Richmond, Virginia 23219

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s.- o COMMONWEALTH OF VIRGINIA )

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COUNTYOF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by E. W. Harrell, who is Vice President - Nuclear Operations, for W. L. Stewart, who is Senior Vice President - Nuclear, of Virginia Electric and Power Company. He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this /3Yday of /1/4t ,199_0..

d My Commission Expires: < dleh S/ , 19 M.

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/l 4'N?Nou Notary Public (SEAL) 1