ML20010D250

Interim Deficiency Rept Re Lockoff Pressure on post-tensioning Sys,Initially Reported 810717.Testing Program Including in-place Tendon Liftoff Sampling & Gauge & Jack Calibr Check Initiated.Next Rept by 811124

ML20010D250
Person / Time
Site:	Bellefonte
Issue date:	08/17/1981
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8108240253
Download: ML20010D250 (2)

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TENNESSEE: VALLEY AUTHORITY CH ATh ANOO'C A. N ESSEE 37401 400 Chestnut Street Tower II

]] [mi' 20 ^6I' August 17, 1981 BLRD-50-438/81-49 /

, J Mr. James P. O'Reilly, Director 3_ ,

Office of Inspection and Enforcement -

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U.S. Nuclear Regulatory Commission g %moes

• Region II - Suite 3100 101 Marietta fitreet .\s /

Atlanta, Georgia 30303 7:EfN'\

Dear Mr. O'Reilly:

4 l BELLEFONTE NUCLEAR PLANT UNIT 1 - LOCKOFF PRESSURE ON POSTTENSIONING i

SYSTEM - BLRD-50-438/81 FIRST INTERIM REPORT l The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on July 17, 1981 in accordance with 10 CFR 50.55(e) as NCR l

BLN CEB 8104. Enclosed is our first interim report. We expect to submit our next report by November 24, 1981. We consider 10 CFR Part 21 to be j applicable to this deficiency.

If you have any questions concerning this matter, please get in touch

! with D. L. Lambert at FTS 857-2581.

Very truly yours, TENNESSEE VALLEY AUTHORITY l

%.> te M. Mills,gnager l

, Nuclear Regulation and Safety Enclosure cc: Mr. Victor Stello, Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission '

Washington, DC 20555 l

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PDR ADOCK 05000438 S PDR An Equal Opportunity Employer a

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• e 2 ENCLOSURE BELLEFONTE NUCLEAR PLANT UNIT 1 l LOCK 0FF PRESSURE ON POSTTENSIONING SYSTEM 10 CFR 50.55(e)

BLRD-50-438 /81-49 '

FIRST INTERIM PEPORT l Description of Deficiency i Inryco, Incorporated is the contractor, contract 75C53-85380, to supply

! and install the posttensioning system for the primary containment structures. A11ewable lockoff stresses for each tendon have been i established by Inryco in accordance with the April 1973 Trial Use Version of the ACI 359 code and the contract specifications. These lockoff stresses are required to provide assurance that the containment structure will have adequate prestreaa force *,o perform its intended safety function.

Ir. order to resolve a problem with certain stressing gauges being out of calibration, Inryco performed liftoff tests on several horizontal tendons. These liftoff tests revealed that, in several cases, lockoff stresses were substantially lower than predicted.

Interim Progress Inryco submitted a program to TVA which outlined their proposed action to investigate the problem and determine the extent and nature of the de ficiency. This program consists, in part, of in-place tendon liftoff samplinge review of material certifications, check of all gauge and jack j calibrations, and material testing. The program has been initiated.

1 Inryco has submitted a progress report to TVA and offered some i preliminary hypotheses as to the cause of the problem which Inryco claims relates to tendon relaxation. Since the testing program is incomplete i

and the hypotheses have not been fully evaluated, discussion of these

hypotheses is premature for this report. Further information will be provided upon completion of the testing program and refinement of the analysis. At this point, no program for corrective action has been established.

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