ML20239A286
| ML20239A286 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 09/02/1998 |
| From: | Wetzel B NRC (Affiliation Not Assigned) |
| To: | Sellman M WISCONSIN ELECTRIC POWER CO. |
| References | |
| GL-97-01, GL-97-1, TAC-M98586, TAC-M98587, NUDOCS 9809080371 | |
| Download: ML20239A286 (6) | |
Text
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UNITED STATES N
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c September'2, 1998 Mr. Michael B. Sellman -
' Chief Nuclear Officer Wisconsin Electric Power Company 231 West Michigan Street l
Milwaukee,WI 53201
SUBJECT:
POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: GENERIC LETTER (GL) 97-01,
" DEGRADATION OF CRDM/CEDM NOZZLE AND OTHER VESSEL CLOSURE HEAD PENETRATIONS"(TAC NOS. M98586 AND M98587)
Dear Mr. Sellman:
On April 1,1997, the staff issued GL 97-01, " Degradation of CRDM/CEDM Nonle 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 nonles (VHPs) 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 requested information and a follow-up response within 120 days of issuance containing the technical details to the staff's information requests in the discussion section of the GL, the staff stated that "individuallicensees 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, i
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
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Reactor Vessel Closure Head Penetration integrity for the Westinghouse Owners Group," and
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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 the staff on July 25,1997.
The staff has determineo by letters dated April 30,1997, and July 30,1997, that you were a member of the WOG and a participant M the WOG integrated program that was developed to address the staff's requests in GL G7-01. In your letters of April 30,1997, and July 30,1997, you also indicated that the information in WEC Topical Report WCAP-14901 is apolicable with respect to the assessment of VHP nonles at Point Beach Nuclear Plant, Units 1 and 2.
e The staff has reviewed your responses to GL 97-01, dated April 30,1997, and July 30,1997, 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 j
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September 2, 1998 contents of Topical Report No. WCAP-14901. The enclosure to this letter forwards the staff's inquiries in the form of a request for additionalinformation (RAl).
The staff requests a response to the RAI within 90 days of the date of this letter. 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 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, ORIGINAL SIGNED BY Beth A. Wetzel, Senior Project Manager Project Directorate ill-1 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301
Enclosure:
Request for Additional Information cc w/ enc!: See next page DISTRIBUTION:
Docket File PUBLIC PD# 3-1 Reading E. Adensam (EGA1)
OGC ACRS E.J. Sullivan M. Kunowski DOCUMENT NAME:G:\\WPDOCS\\PTBEACH\\PTB98586.RAI Ta receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure
- "E" = Copy with attachment / enclosure "N" = No copy l OFFICE PM:PD
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CACarpenter CP lDATE 8/f6 /98 8//8/ /98
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l Mr. Michael B. Sellman Point Beach Nuclear Plant Wisconsin Electric Power Company Units 1 and 2 I
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Mr. John H. O'Neill, Jr.
Ms. Sarah Jenkins Shaw, Pittman, Potts & Trowbridge Electric Division
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2300 N Street, NW Public Service Commission of Wisconsin Washington, DC 20037-1128 P.O. Box 7854 Mr. Richard R. Grigg President and Chief Operating Officer Wisconsin Electric Power Company 231 West Michigan Street Milwaukee, Wisconsin 53201 Mr. Scott A. Patuiski Site Vice President Point Beach Nuclear Plant Wisconsin Electric Power Company 6610 Nuclear Road Two Rivers, Wisconsin 54241 Mr. Ken Duveneck Town Chairman Town of Two Creeks 13017 State Highway 42 Mishicot, Wisconsin 54228 Chairman Public Service Commission of Wisconsin P.O. Box 7854 Madison, Wisconsin 53707-7854 I
Regional Administrator, Region lil U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Resident inspector's Office U.S. Nuclear Regulatory Commission 6612 Nuclear Road Two Rivers, Wisconsin 54241 March 1998
C Request for AdditionalInformation Regarding Utilities Participating in the Westinghouse Owners Group (WOG)
Response to Generic Letter (GL) 97-01
" Background and Methodology for Evaluation of Reactor Vessel Closure Head Penetration Integrity for the Westinghouse Owners Group" Topical. Report No. WCAP-14901, Revision 0
' Applicability of Topical Report No. WCAP-14901, Revision 0, to the Plant-specific Responses to GL 97-01 for Participating Member Utilities and Plants in the WOG
- l. Relationship and Applicability of WCAP-14901, Revision 0, to GL 97-01 and the WOG On April 1,1997, the staff issued GL 97-01, " Degradation of CRDM/CEDM 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 nozzles (VHP' ) at their s
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 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 staff stated that "individuallicensees 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 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 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 vessel head penetrations according to a probabilistic Weibull analysis method that was developed by WEC. In contrast, the WOG member plants subscribing to the content of WCAP-14902, Revision 0, have opted to rank the vessel head penetrations for their facilities i
according to a probabilistic methodology that was developed by another vendor of choice. The i
1 staff has determined by letters dated April 30 and July 30,1997, that you were a member of the WOG and a participant in the WOG integrated prograrn that was developed to address the staffs requests in GL 97-01. In your letters dated April 30 and July 30,1997, you also indicated i
that the information in WEC Topical Report WCAP-14901 is applicable with respect to the assessment of VHP nozzles at Point Beach Nuclear Plant, Units 1 and 2.
ENCLOSURE 1
I i
2 The staff has reviewed your responses to GL 97-01, dated April 30 and July 30,1997, and requires further information to complete its review of your responses as they relate to the WOG's integrated program for assessing VHP nozzles at WOG member plants, and to the contents of Topical Report No. WCAP-14901. The staff requests the following information with respect to the content of your responses to GL 97-01, dated April 30 and July 30,1997, and to the content of WCAP-14901 as it relates to these responses:
- 1. In WCAP-14901 WEC did not provide any conclusions as to what the probabilistic failure model would lead the WOG to conclude with respect to the assessment of PWSCC in WEC-designed vessel head penetrations. With respect to the probabilistic susceptibility model (e.g., probabilistic failure model) provided in WCAP-14901:
- 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 (s) relative to the others.
- b. Describe how the probabilistic failure model in WCAP-14901 for assessing postulated flaws in vessel head penetration nozzles was bench-marked, and provided a list and discussion of the standards the model was bench-marked against.
- c. Provide additional information regarding how the probabilistic failure models in 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 nozzle at the WOG member utilities are addressed in the probabilistic crack initiation and growth models described or referenced in Topical Report No. WCAP-14901.
- 2. Table 1-2 in WCAP-14901 provides a summary of the key tasks in WEC's vessel head penetration nozzle 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 nozzles at your plant (s).
)
- 3. In the NEl letters of January 29,1998 (Ref.1), and April 1,1998 (Ref. 2), NEl indicated l-that inspection plans have been developed for the VHP nozzles at the Farley Unit 2 plant in the year 2002, and the Diablo Canyon Unit 2 plant in the year 2001, i
respectively. The staff has 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 developed by an alternate j
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vendor of choice. The WOG's proposal to inspect the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 plants appears to be based on a composite assessment of j
the VHP nozzles at all WOG member plants. Verify that such a composite ranking I
assessment has been applied to the evaluation of VHP nozzles at your plants. If compo_ site rankings of the VHP nozzles at WOG member plants have been obtained I
from the composite results of the two models, justify why application of the probabilistic susceptibility model described in WCAP-14901, Revision 0, would yield the same comparable relative rankings of the VHP nozzles for your plant (s) as would application of the alternate 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 your plant (s) relative to the susceptibility rankings of the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 plants.
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, Diyision of Engineering, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission L
(Untitled).
- 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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