ML19325E593

Forwards Addl Info on Tech Spec Change Request to Extend Application of F* Tube Plugging Criterion for Steam Generators.F* Criterion Specifies Certain Conditions Be Met Prior to Application to Stated Eddy Current Results

ML19325E593
Person / Time
Site:	Summer
Issue date:	10/27/1989
From:	Bradham O SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Hayes J NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8911080069
Download: ML19325E593 (7)

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I South Carolins Electric & Gas Company 010 S. Bradham I i '

P.O. Box 88 Vice Pruident i

' 83 ~ . Jenbnnyme, SC 29065 Nucl2ar Oporttions j f * ., , (803) 345 4040  :

. .SCE&G

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October 27, 1989

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y Document Control Desk  ;

U. S. Nuclear Regulatory Commission Washington, DL 20555 ATTENTION: Mr. J. J. Hayes, Jr. l

Subject:

Virgil C. Summer Nuclear Station  :

Docket No. 50/395' )

Operating License No. NPF-12 Additional Information to Support the F* Technical. Specification Extension j l

Gentlemen'  !

On October 5, 1989, South Carolina Electric & Gas Company (SCE&G) met with j L the NRC to discuss. plans for the Virgil C. Summer Nuclear Station (VCSNS) j 1' steam generators. One of the topics discussed was the July 24, 1989, '

. Technical Specification Change Request to extend the application of the F* l L tube plugging criterion for the life of the steam generators. The NRC I l requested that additional information on the results of applying the F* i

! criterion be supplied. Attached please find the requested information.  ;

l. i Should you have any questions, please advise.

Very truly yours, 8911080069 891027 PDR ADOCK 05000395Jr f 4 P PNU g l 0. S. Bradham ]

i ARR/OSB: led  !

Attachment I I

c: D. A. Nauman/0. W. Dixon, Jr./T. C. Nichols, Jr. i E. C. Roberts W. A. Williams, Jr. H. G. Shealy S. D. Ebneter M. N. Browne I-l- J. J. Hayes, Jr. S. R. Hunt j' General Managers J. S. Frick i C. A. Price A. M. Monroe L R. B. Clary A. R. Rice K. E. Nodland NSRC J. C. Snelson NPCF g.

R. L. Prevatte RTS (TSP 880027)

J. B. Knotts, Jr. File (813.20) ,

( . i o* Attachment to Document Control Desk Letter c' . October 27, 1989 ,

Page 1 of 6 j Additional Information for F* Application at the Virgil C. Summer Nuclear Station f The F* criterion specifies certain conditions be met prior to application to insitu bobbin coil eddy current results. The specific criteria as defined by the Virgil C. Summer Nuclear Station (VCSNS) Technical Specifications, section 4.4.5.4.a.10, for F* distance is:

F* distance is'the distance into the tubesheet from the face of the tubesheetorthetopofthelasthardroll,whichever15 lower (further into the tubesheet), that has been conservatively chosen to be 1.6 inches.

NOTE: The F* distence includes an eddy current uncertainty of 0.54".

As defined by Section 4.4.5.4.a.11, for F* tube:

F* tube is the tube with degradation equal to or greater than 40%, below the F* distance and not degraded (i.e., no indications of cracking) within the F* distance.

This criterion applies to steam generator tubes found to contain anomalies in l the full mechanical rolled tube sheet region. The F* criterion has been

! applied during the two previous refueling outeges at VCSNS.

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F* Application Process The following information details the process used to apply the F* criterion

, and provides data to illustrate the conservatism found in the assumed eddy

) current testing (ECT) uncertainties included as part of the F* distance.

l The application cf the F* criterion begins with two independent teams of interpreters' review of acquired eddy current data. The findings of each l team are compared and any differences resolved. The resolved findings are l then reported to a person independent of the data interpretation and hard roll contact point determination evolutions. The next sequence in application is to establish the hard roll contact point within the tubesheet for each tube, on an individual tube basis. This determination is l established by the Engineering Services department using the tube sheet roll profile for each tube found to contain an anomaly. After establishing a hard roll contact point, minus the F* distance, a comparison of the elevation of the location of the anomaly and the F* location for each tube is made. The determination whether to plug / repair the tube or leave the tube in service is based on the outcome of this comparison.

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Attachment to Document Control Desk letter  ;

c' . October 27, 1989 '

Page 2 of 6 Eddy Current Testing Data Analysis Comparisons -

A comparison of independent interpreter team findings has been made in an effort to determine 1) the effectiveness of site specific data interpreter pre-job training and 2) the accuracy of location measurements from primary to secondary team members. This comparison consisted of a random sample of applicable ECT data obtained during the most recent October 1988 refueling outage. Location variances between primary and secondary interpretation teams were identified and quantified. The results of this comparison indicated that the average difference in location was 0.093" between the two teams. As shown on the attached graph, 72% of the location variances were within 0.1", while the maximum variation was only 0.4". As an additional comparison, the data interpretation by independent teams of personnel was followed by a third review. This review was conducted using a computerized datascreening(CDS) device. All results from the third review compared favorable with the results from the interpretation teams.

The attached table is a listing of the data sample used for the location variance comparison. The table lists the location reported by each of the interpretation teams, prior to resolution, along with the results of the CDS.

The results of these comparisons illustrate the acceptability, and conservatism, of the ECT uncertainty assumed in the F* application process (i.e.,0.54").

Conclusion Application of the F* criterion at the VCSNS has been demonstrated to be performed in a conservative manner, well within the constraints of the present Technical Specification requirements.

l ma t cument Contrl Desk Letter

, . Page 3 cif 6 l STEAM GENERATOR TUBE '

l- EDDY CURRENT ,

ANOWALY LOCAfl0N VARlANCC PRIWARY TO SECONDARY ANALY515 ftAu i PRIOR TO RESOLUTION f O.4" -

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• Attachment to Document' Control Desk Letter .

October 27, 1989-  :

,'.Page 4 of 6 a

V C Summer Station ,

Steam Generator Tube Fe Application - Anomaly Location Variance Table Anomaly Location Reported Identification Primary Secondary CDS 1 17.8 18.1- 18.1 2 19.8 19.9 19.8 3 19.8 20.0 20.0 4 18.8 19.0 19.0 i 5 20.8 21.2 21.2 6 15.8 16.1 16.1 7 16.8 17.1 17.1 8 18.8 19.0 19.0 9 17.8 18.0 18.0 '

10 15.9 16.1 16.1 11 5.1 5.5 5.5 12 16.1 16.2 16.1 13 18.7 18.9 18.9 14 16.4 16.4 16.4 15 18.7 18.9 18.9 16 16.4 16.4 16.4 17 17.5 17.7 17.7 ,

18 16.0 li6. 2 16.2 19 15.9 16.0 15.9 20 17.9 17.9 '

17.9 l 21 18.8 18.9 18.8 22 19.8 19.9 19.8 23 19.7 19.8 19.7 24 19.0 19.1 19.0 25 19.9 19.7 19.9 26 19.9 19.7 19.9 F 27 19.0 '18.8 19.0 28 18.8 18.8 18.8 29 17.1 17.0 17.1 30 18.9 19.0 18.9 ,

31 17.0 16.9 17.0 32 20.0 19.8 20.0 33 12.9 13.2 13.2 34 18.9 18.7 18.9 35 18.9 19.0 18.9 36 21.2 21.2 21.2 37 21.2 21.2 21.2 38 3.7 3.7 3.7 39 21.2 21.2 21.2 40 18.9 19.0 18.9 41 19.9 20.0 19.9 42 21.2 21.2 21.2 43 17.1 17.1 17.1 44 20.0 20.0 20.0 45 19.9 20.0 19.9 Note: All measurements are in inches, from the tube end.

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Attachment tm Document Control Desk Letter Oct:ber 27, 1989

,,.Page 5 of 6 4

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' Anomaly variance Table Page 2 of 3 Anomaly Location Reported Identification Primary Secondary CDS 46 20.0 20.0 20.0 .

47 19.2 19.2 19.2 48 -20.0 19.9 20.0 49 19.0 19.0 19.0

• 50 21.2 21.2 21.2 51 18.4 18.4 18.4 52 21.2 21.2 21.2 .

53 21.2 R1.2 21.2 54 20.0 20.0 20.0 55 17.6 17.6 17.6 56 18.1 18.1 18.1 57 19.0 19.0 19.0 ' '

58 21.2 21.2 21.2 59 19.9 20.0 19.9 60 16.9 17.1 17.1 61 20.0 20.0 30.0 62 19.8 20.0 20.0 67 18.8 19.0 19.0 64 17.0 17.0 17.0 65 6.7 6.7 6.7 66 18.9 19.0 18.9 67 16.1 16.1 16.1 68 17.0 17.0 17.0 69 17.9 18.1 18.1 70 19.9 20.0 19.9 71 16.1 .16.0 16.0 72 19.9 19.9 19.9 73 21.2 21.2 21.2 74 14.0 14.0 14.0 75 16.9 16.9 16.9 76 21.2 21.2 21.2 i 77 20.0 19.8 20.0-78 10.0 10.0 10.0 79 19.8 19.8 19.8 80 21.1 21.2 21.2 81 16.1 16.0 16.0 82 18.9 18.9 18.9 83 18.9 18.9 18.9 84 19.8 19.9 19.8 85 21.2 21.2 21.2 86 16.0 16.0 16.0 87 19.8 19.9 19.9 88 16.9 17.1 17.1 89 16.1 16.1 16.1 90 16.0 16.0 16.0 Note: All measurements are in inches, from the tube end.

i, 4: Attachment.to Document Control Desk Letter -

l i October 27, 1909 l

, . ]iPage6of6 e- 1 i

Anomaly. Variance Table Page 3 of 3 l l

Anomaly Location Reported

• Identification Primary Secondary CDS 91 18.0 17.9 18.0 92 19.9 19.8 19.9 93 21.2 21.2 21.2 94 21.2 21.2 21.2 95 18.9 19.0 18.9 96 18.9 19.0 18.9 97 18.9 18.8 18.8 98- 20.0 19.8 20.0 99 11.2 11.1 11.2 100 21.2 21.3 21.2 101 16.0 16.1 16.0 102 17.0 17.1 17.0 103 17.9 18.1 18.1

'104 18.9 19.0 18.9 105 20.0 ,

19.9 19.9 106 15.9 16.1 16.1 107 15.0 15.2 15.2 108 18.9 18.9 18.9 109 15.0 15.2 15.2 110 15.0 14.9 15.0 111 17.8 18.0 18.0 112 15.9 15.9 15.9 113 5.4 5.5 5.4 114 16.0 16.0 16.0 115 17.9 17.9 17.9 l

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i Note: All measurements are in inches, from the tube end.

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