ML20151V191

Forwards Request for Addl Info Re GL 97-01, Degradation of Control Rod Drive Mechanism Nozzle & Other Vessel Closure Head Penetrations. Response Requested within 90 Days of Date of Ltr

ML20151V191
Person / Time
Site:	Summer
Issue date:	09/08/1998
From:	Padovan L NRC (Affiliation Not Assigned)
To:	Gabe Taylor SOUTH CAROLINA ELECTRIC & GAS CO.
References
GL-97-01, GL-97-1, TAC-M98602, NUDOCS 9809140145
Download: ML20151V191 (7)

Text

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1. W4 9 p' \ UNITED STATES 4

g j NUCLEAR REGULATORY COMMISSION o, WASHINGTON, D.C. 206&M001

'% .. Septe m ber 8,1998 Mr. Gary J. Taylor Vice President, Nuclear Operations l South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station l

Post Office Box 88 I Jenkinsville, South Carolina 29065 l

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - GENERIC LETTER 97-01, (TAC NO. M98602) l

Dear Mr. Taylor:

On April 1,1997, we issued Generic Letter (GL) 97-01, " Degradation of Control Rod Drive l Mechanism Nozzle and Other Vessel Closure Head Penetrations." Our GL requested, in part, l that licensees describe their plans to inspect the vessel head penetration (VHP) nozzles at their '

respective pressurized water reactor (PWR) designed plants. We required addressees to submit an initial response within 30 days of the GL issuance informing us of their intent to comply with our request. A follow-up response was also due within 120 days of the GL issuance containing the technical response details to our information requests. In the discussion section of the GL, we stated that "individuallicensees may wish to determine their inspection activities based on an integrated industry inspection program. " We also indicated that we did not object to individual PWR licensees basing their inspection activities on an integrated industry inspection program.

As a result, the Westinghouse Owner's Group (WOG) determined that it was appropriate for its members to develop a cooperative, integrated inspection program in response to GL 97-01.

The WOG program is documented in two Westinghouse Electric Corporation (WEC) Topical Reports, WCAP-14901, Revision 0, " Background and Methodology for Evaluation of Reactor Vessel Closure Head Penetration Integrity for the Westinghouse Owners Group," and WCAP-14902,' Revision 0, " Background Material for Response to NRC Generic Letter 97-01:

Reactor Vessel Closure Head Penetration integrity for the Westinghouse Owners Group." The WOG submitted the integrated programs described in WCAP-14901 and WCAP-14902 to us on July 25,1997.

We have reviewed your May 1,1997, and July 30,1997, responses to GL 97-01. We determined that you are a member of the WOG, and are a participant in the WOG integrated program that was developed to address our GL 97-01 requests. In your responses to GL 97-01, you also indicated that the information in WEC Topical Report WCAP-14901 applies to the assessment of VHP nozzles at the Summer plant. In addition, we noted that you indicated in your 120-day response that WCAP-14932, "Probabilistic and Economic Evaluation of Reactor Vessel Closure Head Penetration Integrity for Virgil C. Summer Nuclear Plant," also applied to evaluating VHPs at your plant.

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! 4 2-a Our request for additional information (RAl) is enclosed. Our RAI questions mainly pertain to Topical Report WCAP-14901. However, we request that you generally apply the information requests to WCAP-14932 as well. Please note that we have issued similar requests to other WOG member utilities. As before, we encourage you to address these inquiries in an i

integrated fashion with the WOG and the Nucle'ar Energy institute. However, we request that 4

you identify any deviations from the WOG's integrated program that may be specific to the Summer plant.

I discussed this RAI with Mr. Jim Turkett of your staff on September 1,1998. We mutually agreed that the SCE&G target date to respond to this RAI is within 90 days of the date of this letter. Please call me at (301) 415-1423 if you need to revise the target date.

! Sincerely, i . bd M l L. Mark Padovan, Project Manager j Project Directorate 11-1 Division of Reactor Projects - 1/11

Office of Nuclear Reactor Regulation i

Docket No. 50-395

Enclosure:

Request for Additional Information

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September 8 1998 0 1

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Our request for additional information (RAl) is enclosed. Our RAI questions mainly pertain to Topical Report WCAP-14901. However, we request that you generally apply the information I requests to WCAP-14932 as well. Please note that we have issued similar requests to other l WOG member utilities. As before, we encourage you to address these inquiries in an integrated fashion with the WOG and the Nucle'ar Energy Institute. However, we request that you identify any deviations from the WOG's integrated program that may be specific to the Summer plant.

l l

l discussed this RAI with Mr. Jim Turkett of your staff on September 1,1998. We mutually agreed that the SCE&G target date to respond to this RAI is within 90 days of the date of this I letter. Please call me at (301) 415-1423 if you need to revise the target date.

Sincerely, Original Signed by:

l L. Mark Padovan, Project Manager Project Directorate 11-1 Division of Reactor Projects - t/II Office of Nuclear Reactor Regulation Docket No. 50-395

Enclosure:

Request for Additional Information cc w/ encl: See next page Distribution Docket File PUBLIC PD li-1 Reading OGC ACRS J. Zwolinski L. Plisco, Ril J. Harold J. Medoff DOCUMENT NAME: G:\ SUMMER \ SUM 98602.RAI To receive a copy of this document, indicate in the box: "C" a Copy without auchment/ enclosure "E" a Copy wrth attachtnant/endosure "N" a No copy ///

OFFICE PDil 1/PM _, /-) lEI Poll 1/LA l6l l l PO!!-1/D f)'((,V l NAME MPadovan D EDunnint; ton f6'7h P2 T. Kuo f 8 DAVE 09/ 1 /98 09/ j)98 $/1998 i 0FFICIAL RECORD COPY

September 8.1998 I

l Our request for additional information (RAI) is enclosed. Our RAI questions mainly pertain to Topical Report WCAP-14901. However, we request that you generally apply the infcrmation 1 requests to WCAP-14932 as well. Please note that we have issued similar requests to other i WOG member utilities. As before, we encourage you to address these inquiries in an '

integrated fashion with the WOG and the Nuclear Energy Institute. However, we request that

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you identify any deviations from the WOG's integrated program that may be specific to the Summer plant.

1 I discussed this RAI with Mr. Jim Turkett of your staff on September 1,1998. We mutually

, agreed that the SCE&G target date to respond to this RAI is within 90 days of the date of this i letter. Please call me at (301) 415-1423 if you need to revise the target date.  !

I Sincerely,

)

Onginal Signed by:

L. Mark Padovan, Project Manager Project Directorate 11-1 Division of Reactor Projects - 1/II

Office of Nuclear Reactor Regulation l Docket No. 50-395 i l

Enclosure:

Request for 1

Additional Information cc w/ encl: See next page Distribution  !

' Docket FiW  !

PUBLIC l PD 11-1 Reading OGC ACRS J. Zwotinski l L. Plisco, Ril l

J. Harold J. Medoff DOCUMENT NAME: G:\ SUMMER \ SUM 98602.RAI l Ta receive a copy of this document. Indicate in the box: "C" = Copy without attachment / enclosure "E' = Copy with attachtnent/ enclosure "N" = No copy / /7 0FFICE POII-1/PM ,O lE PDil 1/LA lE l PDil-1/D [M[,V l NAME MPadovan 'M EDunnington ((h P2 T. Kuo Il

~3 DATE 09/ A/98 09/ '/J98 5/ M98 4 0FFICIAL RECORD COPY

Mr. Grry J. Taylor VIRGIL C. SUMMER NUCLEAR STATION i South Carolina Elsetric & Gas Company cc:

Mr. R. J. Whito J. B. Knotts, Jr., Esquire Nuclear Coordinator Winston & Strawn Law Firm S.C. Public Service Authority 1400 L Street, N.W.

c/o Virgil _ C. Summer Nuclear Station Washington, D.C. 20005-3502 Post Office Box 88, Mail Code 802 ~

Jeiikinsville, South Carolina 29065 l

Resident inspector / Summer NPS c/o U.S. Nuclear Regulatory Commission Route 1, Box 64 J+nkinsville, South Carolina 29065 l

Figional Administrator, Region 11 1

!! S. Nuclear Regulatory Commission Ailanta Federal Center 6' Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303 Cnairman, Fairfield County Council-Drawer 60

%1nnsboro, South Carolina 29180 Mr. Virgil R. Autry, Director D! vision of Radioactive Waste Management Bureau of Land & Waste Management Department of Health & Environmental Control 2 BOO Bull Street Columbia, South Carolina 29201 Mr. Robert M. Fowlkes, Manager Operations South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station, Mail Code 303 Post Office Box 88 Jenkinsville, South Carolina 29065 Ms. April R. Rice, Manager Nuclear Licensing & Operating Experience South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station, Mail Code 830 Post Office Box 88 Jenkinsville, South Carolina 29065

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i Enclosure

] Reauest for AdditionalInformation I

in Resoonse to Generic Letter (GL) 97-01 1

4 The technical content provided in WCAP-14901', Revision 0, is basically the same as that I provided in WCAP-14902. The difference is that WOG member plants subscribing to i

WCAP-14901 opted to rank the susceptibility of their vessel head penetrations (VHPs) according to a probabilistic Weibull analysis method. In contrast, the WOG member plants j subscribing to WCAP-14902, Revision 0, opted to rank the VHPs for their facilities according to a probabilistic methodology that another vendor developed.

j. We have reviewed your May 1,1997, and July 30,1997, responses to GL 97-01. We need the l following information to complete our review of your responses. The requested information relates to the WOG's integrated program for assessing VHP nozzles at WOG member plants,

and to the contents of Topical Report No. WCAP-14901 as it relates to these responses

4 i 1. In WCAP-14901, WEC did not determine what the probabilistic failure model would lead

. the WOG to conclude with respect to assessing Primary Water Stress Corrosion i Cracking (PWSCC) in WEC-designed VHPs. With respect to the probabilistic

! susceptibility model (i.e., probabilistic failure model) provided in WCAP-14901:

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a. Provide the susceptibility rankings compiled for the WOG member plants for which

, WCAP-14901 applies. In regard to other WOG member plants to which WCAP-14901 applies, include the basis for establishing the ranking of your plant

, relative to the others.

l b. Describe how the probabilistic failure model in WCAP-14901 for assessing VHP i postulated flaws was benchmarked, and list and discuss the standards the model

! was benchmarked against.

c. Provide additionalinformation regarding how the probabilistic failure models in WCAP-14901 will be refined to allow the input of plant-specific inspection data into the model analysis methodology.

{ d. Describe how variability in product forms, material specifications, and heat treatments used to fabricate each control rod drive mechanism penetration nozzle at j WOG member plants are addressed in the probabilistic crack initiation and growth models described or referenced in Topical Report No. WCAP-14901.

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2. Table 1-2 in WCAP-14901 summarizes key tasks in WEC's VHP assessment program.

The table indicates that the tasks for (1) Evaluation of PWSCC Mitigation Methods, (2)

Crack Growth Data and Testing, and (3) Crack initiation Characterization Studies are not complete and are stillin progress. Since the probabilistic susceptibility models

appear to be dependent, in part, on PWSCC crack initiation and growth estimates, a

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provide your best estimate when WEC will complete these tasks. Also, describe how these activities relate to, and will be used to, update the probabilistic susceptibility assessment of VHP nonles at Summer.

3. The Nuclear Energy Institute indicated in their January 29,1998, and April 1,1998, letters (Refs.1 and 2), that VHP noule Inspection plans have been developed for inspecting the Farley Unit 2 plant in the year 2002, and the Diablo Canyon Unit 2 plant in the year 2001. We noted that although you have endorsed the probabilistic susceptibility model described in WCAP-14901, Revision 0, other WOG member licensees have endorsed a probabilistic susceptibility model an altemate vendor developed. The WOG's proposal to inspect the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 plants appea.s to be based on a composite assessment of the VHP nozzles at all WOG member plants. Verify that such a composite ranking assessment has been applied to the evaluation of VHP nozzles at Summer, if composite rankings were obtained for all of WOG member plants, justify why applying one model would yield the same comparable relative rankings as would applying the other model. Comment on the susceptibility rankings of the VHP nozzles at Summer relative to the susceptibility rankings of the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 planta.

References:

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1. David J. Modeen, Director of Engineering, Nuclear Generation Division, Nuclear Energy l Institute, letter to G. C. Lainas, Acting Director, Division of Engineering, Office of Nuclear I Reactor Regulation, U.S. Nuclear Regulatory Commission, (Untitled), January 19,1998. I

2. David J. Modeen, Director of Engineering, Nuclear Generation Division, Nuclear Energy Institute, letter to G. C. Lainas, Acting Director, Division of Engineering, Office of Nuclear l Reactor Regulation, U.S. Nuclear Regulatory Commission, "

Subject:

Generic Letter 97-01, Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Head Penetrations,"

April 1,1995.

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