ML19305D655

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Final Deficiency Rept Re Potential for Westinghouse Control Rod Guide Tube Support Pins to Break Due to Corrosion Cracking.Westinghouse Evaluation Concludes That Operation Not Jeopardized.Pins Replaced W/Higher Temp Resistant Pins
ML19305D655
Person / Time
Site: North Anna Dominion icon.png
Issue date: 04/10/1980
From: Sylvia B
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
References
327, NUDOCS 8004150342
Download: ML19305D655 (1)


Text

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Vino 1xzA Er.ncraic Axn Powna CoxPANY 9 Hscuxown.VinorxrA 20201 Aia-il 10, 1930 Mr. Janes P. O'Reilly, Director Serial To. 327 Office of Inspection and Enforcenent PC/ICfT:bau U. S. !!uclear Regulatory Conmission Dochet No. 50-339 101 Marietta Street, Suite 3100 Pa rmit 2:o. CPPR-73 Atlanta, Coorgia '30303

Dear Mr. O'Reilly:

Pursuant to the provisions of ICCTR50.55(o), the rPC Pc ; ion II van notified on Ihrch 14, 1980, of a potential for Vestinghouse supplied control rod guide tube support pins, solution heat treated below 1950*F, to break due to stress corrosion cracking, he support pins prnven: lateral novement of the guide tubes and if broken could result in nina11gnennt of the guide tube with possible restriction of the associated control rod movement.

A safety evaluation by Westinghouse has concluded that control rod operation would not be jeopardi::cd by a broken pin for non-l'pper Pead Infection (UHI) plants (i.e. , ?' orth Anna Power Station) due to the snall gap clearance between the non-UllI guide tube and the core plate. As a preventive measure, all support pins in L' nit 2 are being replaced with pf na having a higher heat treatment te=perature. His replacenent vill be completed prior to the installation of the upper internals in the reactor vessel.

Bis is our final report regarding this matter. If further infornation is required, please contact this office.

Very truly yours.

ORIGINAL SIGITED BY B. R. SYLVIA

3. F. Sylvia Mananer-l'uclear Operations cc: !!r. Victor Stello, Director Cf fice of Inspection and Enforcenent
!r. "arold R. Denton, Director ,

Office of ?'uclear Peacter Regulation N\Sw qto q 80 04150 h2