ML18139B183

Part 21 Rept,Originally Reported 790525,re Steam Generator Feet Bolt Hole Discrepancies.Corrosion Removed.Rusted & Galled Threads Cleaned by Running Helicoil Tap Into Bolt Holes Prior to New Helicoil Installation

ML18139B183
Person / Time
Site:	Surry
Issue date:	03/11/1981
From:	Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-81-374-000 162, PT21-81-374, PT21-81-374-000, NUDOCS 8103231098
Download: ML18139B183 (2)

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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND,\'":rRGIN.I.A. 23261 March 11, 1981 Mr. James P. 0 1 Reilly, Director Serial No. 162

_Office of Inspection and Enforcement NO/ESG:ms U. S. Nuclear Regulatory Commission Docket Nos. 50-280 Region II 50-281 101 Marietta Street, Suite 3100 License Nos. DPR-32 Atlanta, Georgia 30303 DPR-37

Dear Mr. 0 1 Reilly:

Under the provisions of the operating license Technical Specifications and/or 10 CFR 21, NRC Region II was notified on May 25, 1979, that a potential signi-ficant deficiency or substantial safety hazard existed at Surry Power Station, Unit No. 2. In letters dated May 31, 1979, and August 10, 1979, details were provided concerning discrepancies found in the Unit 2 steam generator feet bolt holes. The August 10, 1979 letter described the corrective action taken for the Unit 2 bolt holes, and also indicated that the helicoils and bolt holes for the new Unit 1 steam generators would be inspected to ensure required thread engagement.

The Unit 1 helicoil and bolt holes inspection has been completed.

• For each new steam generator lower shell, the helicoils were removed from each of the six bolt holes in each of the four feet. The threads in each bolt hole were visually inspected, and any discrepancies evaluated. Following this, new helicoils were inserted into each hole, and each inspected for proper fit.

Discrepancies were noted at the following locations:

Steam Generator No. 2981: Bolt holes 1,4,6 Steam Generator No. 2982: Bolt holes 1,2,3,4,5,8,9,10,12,16,19,23,24 Steam Generator No. 2983: Bolt hole 11 The di~crepancies noted on steam generator number 2981 and at bolt hole 16 of number 2982 consisted of corrosion or minor instances of missing, high or chipped threads. Other than r*emoving the corrosion, the evaluation indicated that no corrective action was required. The remaining bolt holes were found with rusted, chipped or galled threads. In these instances, the threads were cleaned by running a helicoil tap into the bolt holes prior to installation of the new helicoils.

il03)..3/0~l(

VI!lGIXIA ELECTRIC AXD POWER COMP*..._,, TO e

Mr. James P. O'Reilly 2 As this letter is our final report on this subject, the action described above constitute the final corrective action for the Unit 1 steam generators.

Very truly yours, 1/lik.

B. R/ Sylvia Manager - Nuclear Operations and Maintenance cc: Mr. Victor Stello, Director (3)

Office of Inspection and Enforcement