3F1297-06, Special Rept 97-07:re Hoop Tendon 51H26 That Was Found to Have Normalized lift-off Force of More than 10% Below Predicted Value.Out of Tolerance Tendons Were Returned to Proper pre-stress Level.Commitment Attached

Special Rept 97-07:re Hoop Tendon 51H26 That Was Found to Have Normalized lift-off Force of More than 10% Below Predicted Value.Out of Tolerance Tendons Were Returned to Proper pre-stress Level.Commitment Attached

ML20202G876
Person / Time
Site:	Crystal River
Issue date:	12/06/1997
From:	Grazio R FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F1297-06, 3F1297-6, 97-07, 97-7, NUDOCS 9712100131
Download: ML20202G876 (4)

Text

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Florida Power l-.L T L. .

D3cember 6,1997 3F1297-06 U.S. Nuclear Regulatory Commission At:n: Document Control Desk Washington, D.C. 20555-0001

Subject:

SPECIAL REPORT 97-07 CONTAINMENT TENDONS FOUND OUT OF TOLERANCE

Dear Sir:

Pleara find the enclosed Special Report 97-07, which discusses the finoings, to date, of the twentieth year tendon surveillance testing of the concrete containment building post tensioning system. This report discusses those containment t..adons found out of tolerance during the ongoing surveillance test. This report is being submitted in accordance with improved Technical Specifications 5.7.2.b and Regulatory Guide 1.35, Revision 3.

Sincerely, F e {,0Li .

R. E. Grazi Director .

Nuclear Regulatory Affairs REG /pmp f I

Enclosures l

. xc: Senior Resident inspector ff J

NRR Project Manager Regional Administrator, Region II kkk,kkkkk 0712100131 971206 PU8i ADOCK 05000302 S PDR CRYSTAL RIVER ENERGY COMPLEX: 16760 W. Power une street, Crystal River, Florida 34428 6708 (352)795-6486 A Florida .hogress Company

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U.S. Nuclear Regulatory Commission 3F1297-06 Page R of 4 ,

ENCLQSURE A SPECIAL REPORT 97-07 CONTAINMENT TENDONS FOUND OUT OF TOLERANCE This special report is being submitted in accordance with the reporting requirements of the Crystal River Unit 3 (CR-3) Improved Technical Specifications 5.7.2.b and Regulatory Guide 1.35, Revision 3. The purpose of this report is to provide the details of those conditions found during the ongoing twentieth year +enden surveillance of the CR-3 containment post tensionir.g system. The following cor ditions were observed:

• Two lift off force tests were lower than ninety percent of the predicted value.

• Seven adjacent tr.ndons had actual lift-off force measurements between ninety and ninety-five percent of the predicted value.

• The elongation measured had a ditference of greater than ten percent of the original clongation value for one of the two tendons found with lower than ninety percent of the predicted value.

DES _CalEIl0N During the performance of the twentieth year tendon surveillance of the CR-3 containment post tensioning system. hoop tendon 51H26 was found to have a normalized lift-off force of more than ten percent below the predicted value. Lift-off mear.urements were taken on the hoop tendons locateo directly above (51H27) and directly below (51H25). Tendon 51H25 testei within five percent of the predicted value, which is acceptable. The normalized lift-off force in tendon 51H27 was between ninety and ninety-five percent of the predicted value. The tendon directly above, 51H28, was then tested, rendon 51H28 tested within five percent of the predicted value, which is acceptable. Tendon 51H26 was detensioned and a continuity test was performed. A sample w.re was obtained for material testing. When re-tensioning tendon 51H26, the measured elongation did not meet the acceptance criteria of plus/minus ten percent of the original measured elongation.

Tendon 42H32 was found to nave a normalized lift-off force between ninety and ninety-five percent of the predicted value. Lift-off measurements were taken on the tendons located directly above (42H33) and directly below (42H31). These tendons ware also fcund to have a normalized lift-off force between ninety and ninety-five percent of the predicted value. Additional tendons on each side were tested and the following results were identified:

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l U.S. Nuclear Regulatory Commission 3F1297 06 Page1 of 4 ,

• Tendt ns 42H36, 42H34, 42H30 have a normelized lift-off force between ninety and ninety five percent of the predicted value, e Tendon 42H35 was found to have a normalized lift-off force more than ten percent below the predicted value and is scheduled to be detensioned, a continuity test performed snd a sample wire obtained for material testing.

• Tendons 42H37 and 42H29 tested within five percent of the predicted value, which is acceptable.

The containment is considered to be operable because no individual tendon has had a lif t-off value below the minimum required average pre-stress for the tendon group and preliminary trend data for groups tested did not indicate a predicated loss of pre-stress value prior to the next scheduled tendon surveillance.

ACIl0NS_TAKEN The tendons that were found to be out of tolerance were returned to the proper pre stress level, f

EOLLOW-UP_flEEORI The twentieth year tendon surveillance of the CR-3 containment pt.ct tensioning system is ongoing at this time and is scheduled to be completed on January 5,1998. A final report will be submitted to the NRC 60 days af ter completion of the tendon surveillance and will include the results of the engineering evaluation of the as found conditions.

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I U.S. Nuclear Regulatory Commission 3F129746 Page'4 of 4 ENCLOSURE B COMMITMENTS The following identifies those actions committed to by Florida Power Corporation (FPC) in this document. Any other actions discussed represent intended or planned actions by FPC and are described to the NRC '3taff for their iriformation and are not regulatory commitments.

COMMITMENT COMMITMENT DUE DATE WIT 9 ~ -1 A fina) report will be submitted to tne 60 days af ter NRC 60 days after completion of the completion of the tendon surveillance and " vill include the tendon surveillance, results of the engineering ev,luation of the as found conditions.

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