ML20239A074

Forwards RAI Re Responses to GL 97-01, Degradation of Crdm/Cedm Nozzle & Other Vessel Closure Head Penetrations. Response Requested within 90 Days of Submittal Date

ML20239A074
Person / Time
Site:	Catawba
Issue date:	09/03/1998
From:	Tam P NRC (Affiliation Not Assigned)
To:	Gordon Peterson DUKE POWER CO.
References
GL-97-01, GL-97-1, TAC-M98554, TAC-M98555, NUDOCS 9809080133
Download: ML20239A074 (8)

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NUCLEAR REGULATORY COMMISSION

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Septenber 3, 1998 l

l Mr. Gary R. Peterson Site Vice President Catawba Nuclear Station Duke Energy Corporation 4800 Concord Road York, South Carolina 29745-9635

SUBJECT:

CATAWBA NUCLEAR STATION - GENERIC LETTER (GL) 97-01,

" DEGRADATION OF CRDM/CEDM NOZZLE AND OTHER VESSEL CLOSURE HEAD PENETRATIONS" (TAC NOS. M98554 AND M98555)

Dear Mr. Peterson:

On April 1,1997, the staff issued Generic Letter (GL) 97-01, " Degradation of CRDM/CEDM (Control Rod Drive Mechanism / Control Element Drive Mechanism] Nozzle and Other Vessel Closure Head Penetrations," to the industry requesting, in part, that addressees provide a description of the plans to inspect the vessel head penetration (VHPs) nozzles at their respective pressurized water reactor (PWR) designed plants. With respect to the issuance of the GL, the staff required the addressees to submit an initial response within 30 days of issuance informing the staff of the intent to comply with the requested information and a follow-up response within 120 days of issuance containing the technical details to the staffs information requests. In the discussion section of the GL, the staf' stated that " individual licensees may wish to determine their inspection activities based on an integrated industry inspection program...," and indicated that it 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 Topical Reports issued by the Westinghouse Electric Corporation (WEC), 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 i

the staff on July 25,1997.

The staff has determined by your letters dated April 28 and July 30,1997, that you were a i

member of the WOG and a participant in the WOG integrated program that was developed to address the staffs requests in GL 97-01. In your letter of July 30,1997, you also indicated that the information in WEC Topical Report WCAP-14901 is applicable with respect to the x

assessment of VHP nozzles at Catawba Nuclear Station, Units 1 and 2.

rC The staff has reviewed your responses to GL 97-01, and requires further information to J

i complete its review of your responses as they relate to the WOG's integrated program for

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G. R. Peterson :

' assessing VHP nozzles at WOG member plants, and to the contents of Topical Report WCAP-14901. The enclosure to this letter forwards the staffs inquiries in the form of a request for additionalinformation (RAl). -

The staff requests a response to the RAI within 90 days of the submittal date. It should be noted that similar staff requests have been issued to other WOG member utilities. As was the -

. staffs position before, the staff encourages you to address these inquiries in integrated fashion l

with the WOG and the Nuclear Energy Institute; however, the staff also requests that you identify any deviations from the WOG's integrated program that may be specific to your facilities.~ The staff appreciates the efforts expended with respect to this matter.

Sincerely, Peter S. Tam, Senior Project Manager Project Directorate ll-2 Division of Reactor Projects - 1/ll Office of Nuclear Reactor Regulation

' Docket Nos. 50-413 and 50-414

Enclosure:

Request for Additional-Information cc w/ encl: See next page DISTRIBUTION.

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G. R. Peterson l assessing VHP nozzles at WOG member plants, and to the contents of Topical Report WCAP-14901. The enclosure to this letter forwards the staff's inquiries in the form of a request for additionalinformation (RAI).

i The staff requests a response to the RAI withir1'90 days of the submittal date, it should be noted that similar staff requests have been issued to other WOG member utilities. As was the staff's position before, the staff encourages you to address these inquiries in integrated fashion with the WOG and the Nuclear Energy Institute; however, the staff also requests that you i

identify any deviations from the WOG's integrated program that may be specific to your facilities. The staff appreciates the efforts expended with respect to this matter.

Sincerely, Peter S. Tam, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-413 and 50-414

Enclosure:

Request for Additional information cc w/ encl: See next page i

Catawba Nuclear Station cc:

Mr. M. S. Kitlan North Carolina Electric Membership Regulatory Compliance Manager Corporation Duke Energy Corporation P. O. Box 27306 4800 Concord Road.

. Raleigh, North Carolina 27611 York, South Carolina 29745 Senior Resident inspector Mr. Paul R. Newton U.S. Nuclear Regulatory Commission Legal Department (PB05E).

4830 Concord Road Duke Energy Corporation York, South Carolina 29745 422 South Church Street i

l Charlotte, North Carolina 28201-1006 Regional Administrator, Region 11 U. S. Nuclear Regulatory Commission J. Michael McGarry, Ill, Esquire Atlanta Federal Center Winston and Strawn 61 Forsyth Street, S.W., Suite 23T85 1400 L Street, NW Atlanta, Georgia 30303 l

' Washington, DC 20005 Virgil R. Autry, Director North Carolina Municipal Power Division of Radioactive Waste Management Agency Number 1 Bureau of Land and Waste Management 1427 Meadowwood Boulevard Department of Health and Environmental

' P. O. Box 29513 Control i

Raleigh, North Carolina 27626 2600 Bull Street Columbia, South Carolina 29201-1708 County Manager of York County York County Courthouse L. A. Keller York, South Carolina 29745 Manager - Nuclear Regulatory Licensing Piedmont Muriicipal Power Agency Duke Energy Corporation 121 Village Drive -

526 South Church Street Greer, South Carolina 29651 Charlotte, North Carolina 28201-1006 I

Ms. Karen E. Long Saluda River Electric Assistant Attorney General.

P. O. Box 929 North Carolina Department of Justice Laurens, South Carolina 29360 P. O. Box 629 Raleigh, North Carolina 27602 Mr. Steven P. Shaver Senior Sales Engineer Elaine Wathen, Lead REP Planner Westinghouse Electric Company

' Division of Emergency Management 5929 Carnegie Blvd.

116 West Jones Street Suite 500

-Raleigh, North Carolina 27603-1335 Charlotte, North Carolina 28209

l Catawba Nuclear Station cc:

Mr. T. Richard Puryear i

Owners Group (NCEMC)

Duke Energy Corporation 4800 Concord Road York, South Carolina 29745 Richard M. Fry, Director Division of Radiation Protection North Carolina Department of Environment, Health, and Natural Resources 3825 Barrett Drive Raleigh, North Carolina 27609-7721

Reauest for Additional Information l

Resoonse to Generic Letter 97-01 i-

"Backaround and Methodoloov for Evaluation of Reador Vessel Closure Head Penetration Intearity for the Westinghouse Owners Grouo"

. Tonical Reoort WCAP-14901. Revision 0 L

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Relationship and Applicability of WCAP-14901, Revision 0, to Generic Letter 97-01 and the Westinghouse Owners Group On April 1,1997, the staff issued Generic Letter (GL) 97-01, " Degradation of CRDM/CEDM

- [ Control Rod Drive Mechanism / Control Element Drive Mechanism) Nozzle and Other Vessel Closure Head Penetrations," to the industry requesting, in part, that addressees provide a description of the plans to inspect the vessel head penetration (VHPs) nozzles at their respective pressurized water reactor (PWR) designed plants. With respect to the issuance of the GL, the staff required the addressees to submit an initial response within 30 days of

- issuance informing the staff of the intent to comply with the requested information and a I

followup response within 120 days of issuance containing the technical details to the staffs i

information requests. In the discussion section of the GL, the staff stated that " individual l

licensees may wish to determine their inspection activities based on an integrated industry inspection program...," and indicated that it did not object to individual PWR licensees basing their inspection activities on an integrated industry inspection program.

As a result, the Westinghouse Owners 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 Topical Reports issued by the Westinghouse Electric Corporation (WEC), 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:

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- Reactor Vessel Closure Head Penetration Integrity for the Westinghouse Owners Group."

The technical content provided in WCAP-14901, Revision 0, is basically the same as that provided in WCAP-14902. The difference with regard to the reports is that WOG member plants subscribing to the content of WCAP-14901 have opted to rank the susceptibility of their

- VHPs according to a probabilistic Weibull analysis method that was developed by WEC. In i

contrast, the WOG member plants subscribing to the content of WCAP-14902, Revision 0, have opted to rank the VHPs for their facilities according to a probabilistic methodology that was developed by another vendor of choice. The staff has determined by Duke Energy Corporation

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letters dated April 28 and July 30,1997, that you were a member of the WOG and a participant in the WOG integrated program that was developed to address the staffs requests in GL 97-01.

In your letter dated July 30,1997, you also indicated that the information in WEC Topical Report WCAP-14901 is applicable with respect to the assessment of VHP nozzles at Catawba f

Nuclear Station (Catawba), Units 1 and 2.

l Enclosure

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The staff has reviewed your responses to GL 97-01, and requires further information to complete its review of your responses as they relate to the WOG's integrated program for assessing VHP nonles at WOG member plants, and to the contents of Topical Report WCAP-14901. The staff requests the following information with respect to the content of your responses to GL 97-01, and to the content of WCAP-14901 as it relates to these responses:

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1. In WCAP-14901, WEC did not provide any conclusions as to what the probabilistic failure l

model would lead the WOG to conclude with respect to the assessment of primary water stress-corrosion cracking (PWSCC) in WEC-designed VHPs. With respect to the probabilistic susceptibility model (e.g., 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 is applicable. In regard to other WOG member plants to which WCAP-14901 is applicable, include the basis for establishing the ranking of your plant relative to the others.

b. Describe how the probabilistic failure model in WCAP-14901 for assessing postulated j

flaws in VHP nonles was benchmarked, and provide a list and discussion of the j

standards the model was benchmarked against.

c. Provide additionalinformation regarding how the probabilistic failure models in j

WCAP-14901 will be refined to allow the input of plant-specific inspection data into the model's analysis methodology.

d. Describe how the variability in product forms, material specifications, and heat treatments used to fabricate each CRDM penetration nonle at the WOG member

- utilities are addressed in the probabilistic crack initiation and growth models described or referenced in Topical Report WCAP-14901.

2. Table 1-2 in WCAP-14901 provides a summary of the key tasks in WEC's VHP nonle 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 have not been completed and are still in progress. In light of the fact that the probabilistic susceptibility models appear to be dependent, in part, on PWSCC crack initiation and growth estimates, provide your best estimate when these tasks will be completed by WEC, and describe how these activities relate to and will be used to update the probabilistic susceptibility assessment of VHP nonles at your plant.

3. In the Nuclear Energy Institute letters of January 29,1998 (Ref.1), and April 1,1998

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(Ref. 2), NEl indicated that inspection plans have been developed for the VHP nonles at the Farley Unit 2 plant in the year 2002, and the Diablo Canyon Unit 2 plant in the year 2001, respectively. The staff has noted that although you have endorsed the probabilistic susceptibility model described in WCAP-14901, Revision 0, other WOG member licensees

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have endorsed a probabilistic susceptibility model developed by an attemate vendor of

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choice. The WOG's proposal to inspect the VHP nonles at the Farley Unit 2 and Diablo Canyon Unit 2 plants appears to be based on a composite assessment of the VHP nonles

. at all WOG member plants. Verify that such a composite ranking assessment has been applied to the evaluation of VHP nonles at Catawba. If composite rankings of the VHP

- nonles at WOG member plants have been obtained from the composite results of the two 1

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.. models, justify why application of the probabilistic susceptibility model described in WCAP-14901, Revision 0, would yield the same comparable relative rankings for the VHP nozzles for Catawba as would application of the altemate probabilistic susceptibility model used by the WOG member plants not subscribing to WCAP-14901, Revision 0. Comment on the susceptibility rankings of the VHP nozzles at Catawba relative to the susceptibility rankings of the VHP nozzles at Farley Unit'2 and Diablo Canyon Unit 2.

REFERENCES

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

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2. April 1,1995 - Letter from David J. Modeen, Director of Engineering, Nuclear Generation Division, Nuclear Energy institute, to Mr. G. C. Lainas, Acting Director, Division of Engineering, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission,

SUBJECT:

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

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