ML20003D590

Final Deficiency Rept,Originally Reported on 810220,re Bent, Shifting & Dislocated Rebar/Anchor Bolts.Caused by Drawing Interpretation Errors & Improper Handling & Rigging Practices.Rebars Straightened & New Bolts Grouted in

ML20003D590
Person / Time
Site:	Yellow Creek
Issue date:	03/20/1981
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, YCRD-50-566-81, NUDOCS 8103270712
Download: ML20003D590 (3)

Text

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7 . . '<l Mr. James O'Reilly, Director b i U')

Office of In ection and Enforcement U.S. Nuclear Rhgulatory Commission Region II - Sui 3100 101 Marietta Stre t Atlanta, Georgia 303

Dear Mr. O'Reilly:

YELLOW CREEK NUCLEAR PLANT UNIT 1 - REBAR/ ANCHOR BOLTS NONCONFORMANCE -

YCRD-50-566/81 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector J. Crlenjak on February 20, 1981, in accordance with 10 CFR 50 55(e) as NCR YC-154. Enclosed is our final report.

If you have sny questions concerning this matter, please get in touch with D. L. Lambert at FTS 857<>2581.

Very truly yours, TENNESSEE VALLET AUTHORITT i

L. M. Mills, Manager l Nuclear Regulation and Safety Enclosure cc: Mr. Victor Stello, Jr., Director (Enclosure) l Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission l Washington, DC 20555 t

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ENCLOSURE YELLOW CREEK NUCLEAR PLANT UNIT 1 REBAR/ ANCHOR BOLTS NONCONFORMANCE YCRD-50-566/81-05 10 CFR 50.55(e)

FINAL REPORT Description of Deficiency Nonconformance Report (NCR) No. YC-154 was upgraded to significant because of eight previous related NCR's concerning missing, mislocated, and bent reinforcing bars and anchor bolts that were discovered during January 1981. These nonconforming conditions are of two general types.

(1) Six NCR's (YC-145, -147, -148, -150, -153, and -154) concerned a total of 22 rebars and two anchor bolts that were bent slightly or shifted during or immediately after concrete placement. The apparent causes of these nonconformances were improper handling and rigging practices by craftsmen.

(2) Three NCR's (YC-146, -151, and 152) concerned four anchor bolts that were mislocated by five inches, and omitted formwork and dowels.

These discrepancies were caused by drawing interpretation errors by the craftsmen, engineers, and inspectors.

Safety Implications TVA's primary concern was the generic implications of this NCR and eight previous NCR's. TVA's position is that a condition (a major degradation of essential safety-related systems) might have occurred-now or in the future which could have adversely affected the safe operations of the plant.

Corrective Actions Type one nonconforming conditions were evaluated and dispositicned by TVA's Engineering Design (EN DES). NCR's YC-145, -147, -148, and

-150 were dispositioned by straightening the reinforcing bars. NCR YC-153 was dispositioned by adding one additional rebar'. NCR YC-154 was dispositioned by changing the placement of adjoining rebars.

Type two nonconforming conditions were evaluated and dispositioned by EN DES as follows: (1) New anchor, bolts and dowels were grouted in, and (2) concrete was chipped away and the rebar placement lowered, which corrected the problem of rebars that were mislocated because of omittsd fccmwork.

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Craftsmen were instructed to take special precaution in handling and rigging of materials and during concrete placement. ' darning signs were erected to renind the craftsmen that they must not bend or cut rebar without proper authorization. Further, they were instructed to notify the engineer if rebars shifted during concrete placement so that corrective action could be taken. Engineers and inspectors were instructed to verify stabilization of rebar prior to concrete placement, and the concrete inspectors were additionally instructed to be especially alert for rebar damage during placement.

In addition to the above, the following was initiated to preclude recurrence:

(1) A detail takeoff checklist for each concrete pour will be supplied by Quality Control Material and Civil personnel.

Drawing takeoffs are lists of all materials (number of rebar, size of rebar, and general location, etc.) used during placement.

(2) Independent reviews of drawing takeoffs were immediately instituted by Quality Control inspectors.

(3) Craftsmen have been ins *ructed to use their fabrication takeoff to verify that all materials are included in the pours.

(4) The appropriate site project engineers were instructed on February 12,.1981, to make a thorough study of all drawings and to make sure that all field change requests were i=plemented en those drawings before checking pours.

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