ML20237D510
| ML20237D510 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 08/20/1998 |
| From: | Thomas K NRC (Affiliation Not Assigned) |
| To: | Randolph G UNION ELECTRIC CO. |
| References | |
| GL-97-01, GL-97-1, TAC-M98551, NUDOCS 9808260245 | |
| Download: ML20237D510 (8) | |
Text
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30006 4001 o,%,
. August 20, 1998
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Mr. Garry L. Randolph Vice President and Chief Nuclear Officer Union Electric Company Post Office Box 620 Fulton, Missouri 65251
SUBJECT:
' REQUEST FOR ADDITIONAL INFORMATION (RAI)- UNION ELECTRIC COMPANY - CALLAWAY PLANT, UNIT 1 (TAC M98551)
Dear Mr. Randolph:
- On April 1,1997, the staff issued Generic Letter (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 " 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 Owners Group 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, Revision 0, and WCAP-14902, Revision 0, to the staff on July 25,1997. The staff has reviewed your responses to GL 97-01, dated May 1,1997 and July 17,1997, and determined by your g
I responses that you were a member of the WOG and a participant in the WOG integrated program that was developed to address degradation in Westinghouse dessigned vessel head penetration (VHP) nonles, and the staff's requests in GL 97-01. However, the staff could not
. determine after reviewing your responses which of the two Westinghouse Generic Topical Submittals, WCAP-14901, Revision 0, or WCAP-14902, Revision 0, is being endorsed for the assessment of the VHP nonles at the Callaway Plant.
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Mr. Garry L. Randolph August 20, 1998 The staff 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. The enclosure to this letter forwards staff's inquiries in the form of a request for additional information (RAl). The estaff requests a response to the RAI within 90 days of the date of this letter, it should 'De 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 an integrated fashion with the WOG and the Nuclear Energy Institute (NEI); however, the
. staff also requests that you identify any deviations from the WOG's integrated program that may be specific to the Callaway Plant. The staff appreciates the efforts expended with respect to this matter.
Sincerely, j
Original Signed By Kristine M. Thomas, Project Manager 1
Project Directorate IV-2 Division of Reactor Projects Ill/IV Office of Nuclear Reactor Regulation Docket No. 50-483 DISTRIBUTION-Docket File ACRS
Enclosure:
Request for Additional PUBLIC OGC Information PDIV-2 Reading JHarold, DRPE EAdensam TSullivan, EMCB cc w/ encl: See next page WBateman WJohnson, RIV KThomas PGwynn, RIV
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EPeyton DOCUMENT NAME: CAL 98551.RAI OFC PDIV-2/PM PDIV-2/LA NAME KN as E8ehE DATE 8QO/98 8GCy98 OFFICIAL RECORD COPY
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Mr. Garry L. Randolph August' 20, 1998 4
cc w/ encl:
i Professional Nuclear Mr. Otto L. Maynard Consulting, Inc.
President and Chief Executive Officer 19041 Raines Drive Wolf Creek Nuclear Operating Corporation Derwood, Maryland 20855 Post Office Box 411
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Burlington, Kansas 66839 John O'Neill, Esq.
Shaw, Pittman, Potts & Trowbridge Mr. Dan 1. Bolef, President 2300 N. Street, N.W.
Kay Drey, Representative Washington, D.C. 20037 Board of Directors Coalition for the Environment Mr. H. D. Bono 6267 Delmar Boulevard Supervising Engineer University City, Missouri 63130 Quality Assurance Regulatory Support Union Electric Company Mr. Lee Fritz Post Office Box 620 Presiding Commissioner Fulton, Missouri 65251 Callaway County Court House 10 East Fifth Street U.S. Nuclear Regulatory Commission Fulton, Missouri 65151 Resident inspector Office 8201 NRC Road Mr. Alan C. Passwater, Manager Steedman, Missouri 65077-1302 Licensing and Fuels Union Electric Company Mr. J. V. Laux, Manager Post Office Box 6614P Quality Assurance St. Louis, Missouri 63166-6149 Union Electric Company Post Office Box 620 Fulton, Missouri 65251 Manager-Electric Department Missouri Public Service Commission 301 W. High Post Office Box 360 Jefferson City, Missouri 65102 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower & Pavilion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Mr. Ronald A. Kucera, Deputy Director Department of Natural Resources P.O. Box 176 Jefferson City, Missouri 65102 l
Request for Additional information Regarding Utilities Participating in the Westinghouse Owners Group (WOG) Response to Generic Letter (GL) 97-01 Applicability of the WOG Integrated Program for Assessing Vessel Head Penetration (VHP) Nozzles in Westinghouse Designed Nuclear Plants
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to the Plant-specific Responses to GL 97-01 for Participating
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Membei Utilities and Plants in the WOG
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Relationship and Anolicability of WCAP-14902. Revision O. to GL 97-01 and the WOG j
On April 1,1997, the staff issued Generic Letter (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 (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 " 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 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-14902, Revision 0, is basically the same as that provided in WCAP-14901, Revision 0. 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 VHP nozzleo 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 VHP nozzles for their facilities according to a probabilistic methodology tnat was developed by another vendor of choice. The staff has determined by letters dated May 1,1997 and July 17,1997, that you were a member of the WOG and a participant in the WOG integrated program that was developed in address degradation in l
Westinghouse designed VHP nozzles, and the staff's requests in GL 97-01. However, the staff
[
could not determine after reviewing your responses which of the two Westinghouse Generic l
Topical Submittals, WCAP-14901, Revision 0, or WCAP-14902, Revision 0, is being endorsed for the assessment of the VHP nozzles at the Callaway Plant.
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. The staff requires further information to complete its revlaw of your responses as they relate to the WOG's integrated program for assessing VHP nozzles at WOG member plants. The staff requests the following information with respect to the content of your responses to GL 97-01, dated May 1,1997 and July 17,1997, and to the WOG's integrated program for assessing VHP nozzles at WOG member plants:
1.
Indicate which Westinghouse Topical Report, WCAP-14901, Revision 0, or j
WCAP-14902, Revision 0, is being endorsed for the astessment of VHP nozzles at the j
Callaway Plant, and which crack initiation and growth susceptibility model is being used 1
for the assessment of the VHP nozzles at the Callaway Plant.
2.
Provide the following information if Topical Report WCAP-14901 Revision 0, is being endorsed for the VHP nozzles at the Callaway Plant; otherwise skip to information Request 3.
a.
In WCAP-14901, Revision 0, 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:
(1)
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 t' asis for establishing the ranking of the Callaway Plant relative to the others.
(2)
Describe how the probabilistic failure model in WCAP-14901 for assessing postulated flaws in vessel head penetration nozzles was bench-marked, and provide a list and discussion of the standards the model was bench-marked against.
(3)
Provide additional information regarding how the probabilisuc failure models in WCAP-14901 will be refined to allow the input of plant-specific inspection data into the model's analysis methodology.
(4)
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.
b.
Table 1-2 in WCAP-14901 provides a summary of the key tasks in WEC's VHP nozzle assessment program. The table indicates that the tasks for (1) evaluation of PWSCC mitigation methods, (2) craick growth data and testing, and (3) crack initiation characterization studies have not been completed and are still in l
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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 l
your best estimate when these tasks will be completed by WEC, and describe l
how these activities relate to and will be used to update the probabil;stic susceptibility assessment of VHP nonles at the Callaway Plant.
I c.
In the NEl letters of January 29,1998 (Ref.1), and April 1,1998 (Ref. 2), NEl indicated 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, respectively. The staff has noted that although you have endorsed the probabilistic susceptibi!ity model described in WCAP-14901, Revision 0, other WOG member licensees have endorsed a probabilistic susceptibility model developed by an attemate 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 the VHP nozzles at all WOG member plants. Verify that such a composite ranking assessment has been applied to the evnluation of VHP nozzles at the Callaway Plant. If composite rankings of the VHP nozzles at WOG member plants have been obtained 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 the Callaway Plant 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 the Callaway Plant relative to the susceptibility rankings of the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 plants.
3.
Provide the following information only if Topical Report WCAP-14902, Revision 0, is being endorsed for the VHP nozzles at your plant.
a.
WEC and the WOG did not provide a description of the crack initiation and growth susceptibility model used for the assessment of WEC vessel head penetration (VHP) nozzles in plants endorsing WCAP-14002, Revision 0.
Provide a description of the crack initiation and growth susc6phility model used for assessment of the VHP nozzles at the Callaway Plant.
b.
In WCAP-14902, Revision 0, 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 penetration (VHP) nozzles. With respect to the probabilistic susceptibility model (e.g., probabilistic failure model) referenced in WCAP-14902:
(1)
Provide tN Susceptibility ranking of the Callaway Plant as compiled from the crack initiation and growth analysis of the VHP nozzles for the Callaway Plant to that compiled for the other WOG member plants for which WCAP-14902, Revision 0, is applicable.
L.
a (2)
Describe how the probabilistic failure (crack initiation and growth) model in used for the assessment of the VHP nozzles at the Callaway Plant was bench-marked, and provide a list and discussion of the standards the model was bench-marked against.
(3)
Provide additional information regarding how the probabilistic failure (crack initiation and growth) models for the assessment of VHP nozzles at the Callaway Plant will be refined to allow the input of plant-specific inspection data into the model's analysis methodology.
(4)
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-14902, Revision O.
c.
Table 1-2 in WCAP-14902, Revision 0, provides a summary of the key tasks in WEC's VHP noule assessment program. The tables indicate 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 activitios relate to and will be used to update the probabilistic susceptibility assessment of VHP nozzles at your plant, d.
In the NEl letters of January 29,1998 (Ref.1), and April 1,1998 (Ref. 2), NEl indicated 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, respectively. The staff has noted that although you have decided to l
apply an attemate probabilistic susceptibility model to the assessment of the VHP nozzles at your plant, other WOG member licensees, including the l
Southem Nuclear Operating Company and the Pacific Gas and Electric j
Company, the respective licensees for the Farley units and the Diablo Canyon units, have selected to apply the susceptibility model described in WCAP-14901, i
Revision 0, to the assessment of VHP nozzles at their plants. The WOG's l
proposal to inspect VHP at Farley Unit 2 and Diablo Canyon Unit 2 appears to be I
based on an 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 the Callaway Plant. If composite rankings of the VHP nozzles at WOG member plants have been obtained from the composite results of the two models, justify why application of the attemate l
probabilistic susceptibility model being for the assessment of of VHP nozzles at your plant would yield the same comparable relative rankings as would application of the probabilistic susceptibility model used by the WOG member plants subscribing to the contents of WCAP-14901, Revision O. Comment on the i.
susceptibility rankings of the VHP nozzles at the Callaway Plant relative to the susceptibility rankings of the VHP nozzles at the Farley Unit 2 and Diablo Canyon Unit 2 plants.
l References 1.
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),
January 19,1998.
2.
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,'" April 1,1995.
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