ML20128P068

Requests Return of Surveillance Frequency for Moving Control Rod Assemblies from Weekly Interval Back to 31-day Interval Required by Tech Specs,Per 820804 Commitment.Justification Provided

ML20128P068
Person / Time
Site:	North Anna
Issue date:	05/24/1985
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, John Miller Office of Nuclear Reactor Regulation
References
85-388, NUDOCS 8506030453
Download: ML20128P068 (2)

Text

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'/Mr. Rarold!RU Dentoni, Director Serial No.85-388 Office"of NucleaTRiactor Regulation NAPS /JHL: ace Attn: Mr. James R. Miller, Chief Docket Nos. 50-338 Operating Reactors Branch No. 3 50-339 Division of Licensing Licence Nos. NPF-4 U. S. Nuclear Regulatory Commission NPF-7

. Washington, D.C. 20555 Gentlemen:

VIRGINIA P0'JER NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 REACTOR C00LAhT SYSTEM THERMAL SLEEVES Virginia Power letter dated August 4, 1982, for North Anna Unit No. 2, committed to a program of increased surveillance to address the potential concerns of loose parts in the reactor coolant system as a result of degraded thermal sleeves. The commitment was to perform, on a weekly basis, control rod exercises to verify the free movement of the control rod assemblies. This commitment was also made for North Anr.a Unit No.1, in Virginia Power letter dated October 12, 1982, and was subsequently approved in the NRC Safety Evaluation Report (SER), dated January 11, 1983, that detailed Virginia Power's corrective actions and justification for continued operation.

Virginia Power desires to return the surveillance frequency for moving the control rod assemblies from a weekly interval back to the 31 day interval required by the Technical Specifications. The justification for the reduced surveillance is provided below.

The Loose Parts Monitoring System (LPMS) was enhanced as a result of the degraded thermal sleeves by adding accelerometers. If a thermal sleeve or a part of a thermal sleeve were to migrate in the reactor coolant system it will be quickly picked up on the LPMS or the Metal Impact Monitoring System (MIMS). However, to date there have been no indications that a continuing problem exists with thermal sleeves. The remaining thermal sleeves in the Unit 1 and 2 reactor coolant system were inspected by radiographic inspection techniques during the last refueling outages and the inspection results did not indicate any significant flaws in the thermal sleeve tack welds or missing thermal sleeves.

8506030453 B5052 338 DR ADOCK 050 40

I

. I O

With the LPMS and MIMS to detect any indication of a migrating thermal sleeve, daily audible check of the LPMS by engineering personnel, and the already present requirement to move the control rods once per 31 days per Technical Specification 4.1.3.1.2, Virginia Power believes that there is sufficient justification to reduce the interval for testing the control rod assemblies to at least every 31 days.

V gy truly yours, s

x W. L. Stewart cc: Dr. J. Nelson Grace Regio'nal Administrator Region II Mr. M. W. Branch NRC Resident Inspector North Anna Power Station