ML20204F103
| ML20204F103 | |
| Person / Time | |
|---|---|
| Issue date: | 03/21/1999 |
| From: | Strosnider J NRC (Affiliation Not Assigned) |
| To: | Modeen D NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| GL-97-01, GL-97-1, NUDOCS 9903250216 | |
| Download: ML20204F103 (5) | |
Text
, pa anog g k
, g j UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2066H001
,,,* March 21, 1999 Mr. David J. Modeen Director of Engineering Nuclear Generation Division Nuclear Energy Institute 1776 i Street, NW Washington, DC 20006-3708
SUBJECT:
REVIEW OF GENERIC RESPONSE TO THE NRC REQUESTS FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 97-01
Dear Mr. Modeen:
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 that j
addressees provide a description of the plans to inspect the vessel head penetration (VHP) 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 requested information and a follow-up response within 120 days of issuance containing the technical details to the staffs information requests.
The industry's responses to the GL included both generic responses from the respective Pressurized Water Reactor Owners Groups (PWROGs), and a plant-specific response from each PWR owned by an NRC licensed utility. These generic responses were coordinated by the Nuclear Energy Institute (NEI), and included submittal of Topical Report BAW-2301 on behalf of the Babcock & Wilcox Owners Group members, Topical Report CE NPSD 1085 on behalf of the Combustion Engineering Owners Group members, and Topical Reports WCAP-14901 and WCAP-14902, on behalf of Westinghouse Owners Group members. Each of these reports provided the probabilistic failure model that was used to assess and rank the relative susceptibility of a participating plant's VHP nozzles to undergo primary water stress corrosion
! cracking (PWSCC) over time. The staff's review included a review of both the generic i
responses and plant-specific responses to the GL. During the review, the staff determined that -
some additional information was needed for completion of the review. The staff, therefore, issued a series of requests for additionalinformation (RAls) to each of the addressees covered under the scope of the GL. The RAls included the following generic requests: ,
1) 1.
the probabilistic susceptibility ranking for a plant's VHP nozzles to undergo PWSCC 2.
relative to the rankings for the rest of the industry /O a description of how the respective susceptibility models were benchmarked d 4
{ 3.
a description of how the variability in the product forms, material specifications, and heat treatments used to fabricate a plant's VHP nozzles were addressed in the susceptibility models 3 y(M leh// O 9903250216 990321 PDR REVGP ERONUMRC ,5yW.cfV vs
. E' w
4.
a desenption of how the models would be refined in the future to include plant-specific inspection results However, as was the case for the earlier responses to the GL, the staff recommended that the addressees combine their efforts with those of the NEl, the PWROGs, and the Electric Power Research Institute in order to prompt a coordinated, generic response to the RAls.
The staff has received and completed its review of NEl's submittal of December 11,1998, which I provided the generic response to the RAls on behalf of the PWR industry, and in addition proposed an integrated program on behalf of the industry. Your submittal accomplished the following objectives:
1.
Clarified that only two susceptibility models are currently being adopted by the industry for the assessment of VHP nozzles in the PWR industry.
2.
Confirmed that participating members of the CEOG had opted to use the susceptibility model designed by the Dominion Engineering Company as the basis for ranking the VHP nozzles in CE designed plants.
3.
Amended the probabilistic ranking histograms to identify the plants which fell into the respective histogram ranking groups.
4.
Addressed how each of the susceptibility models were benchmarked.
5.
Addressed how each of the susceptibility models would be refined to include plant-specific inspection results. l 6.
Addressed how the variability in product forms, material specifications, and heat treatmants used for fabrication of VHP nozzles were addressed in each of the respective susceptibility models.
The initial generic responses to GL 97-01, when taken in context with the information in your response of December 11,1999, provide an acceptable approach for adriressing the potential for PWSCC to occur in the VHP nozzles of PWR facilities. The staff, therefore, concludes that )
the integrated program proposed by NEl for VHP nozzles is acceptable, and that the licensees responding to the GL may refer to the integrated program as a basis for assessing the postulated occurrence of PWSCC in PWR-design VHP nozzles. It is anticipated that closure of the staff's reviews of the plant-specific responses will be completed in the near-term, and that a NUREG will follow which summarizes the staff's and industry's efforts in addressing this issue. '
Sincerely, M
Jack R. Strosnider, Director Divisiof Engineering Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission
- 4. description of how the models would be refined in the future to include plant-specific inspection results However, as was the case for the earlier responses to the GL, the staff recommended that the addressees combine their efforts with those of the NEl, the PWROGs, and the Electric Power Research Institute in order to prompt a coordinated, generic response to the RAls.
The staff has received and completed its review of NEl's submittal of Decemh 11,1998, which provided the generic response to the RAls on behalf of the PWR industry, and in addition proposed an integrated program on behalf of the industry. Your submittal accomplished the following objectives:
1.
Clarified that only two susceptibility models are currently being adopted by the industry for the assessment of VHP nozzles in the PWR industry.
- 2. Confirmed that participating members of the CEOG had opted to use the susceptibility model designed by the Dominion Engineering Company as the basis for ranking the VHP nozzles in CE designed plants.
- 3. Amended the probabilistic ranking histograms to identify the plants which fell into the respective histogram ranking groups.
- 4. Addressed how each of the susceptibility models were benchmarked.
- 5. Addressed how each of the susceptibility models would be refined to includa plant-specific inspection results.
- 6. Addressed how the variability in product forms, material specifications, and heat treatments used for fabrication of VHP nozzles were addressed in each of the respective susceptibility models.
The initial generic responses to GL 97-01, when taken in context with the information in your response of December 11,1999, provide an acceptable approach for addressing the potential for PWSCC to occur in the VHP nozzles of PWR facilities. The staff, therefore, concludes that the integrated program proposed by NEl for VHP nozzles is acceptable, and that the licensees responding to the GL may refer to the integrated program as a basis for assessing the postulated occurrence of PWSCC in PWR-design VHP nozzles. It is anticipated that closure of the staff's reviews of the plant-specific responses will be enmpleted in the near-term, and that a NUREG will follow which summarizes the staff's and industej's efforts in addressing this issue.
Sincerely, Jack R. Strosnider, Director Division of Engineering Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Distribution: File Center PDR EMC8RF SCoffin BJElliot JHarold DOCUMENT NAME: G:\MEDOF8CRDMGCOL.WP.D -
OFFICE EMCB:DE [ EMp M4 E.EMCSph , b_ DD:DE q D[Db NAME JMedoff k E ORHWes m n JRdt snider DATE j//*//9 b/ /99 3/h/99 b / IC[ /99 9 /ZI /99 OFFICIAL RECORD COPY
- 4. description of how the models would be refined in the future to include plant-specific inspection results However, as was the case for the earlier responses to the GL, the staff recommended that the addressees combine their efforts with those of the NEl, the PWROGs, and the Electric Power Research Institute in order to prompt a coordinated, generic response to the RAls.
The staff has received and completed its review of NEl's submittal of December 11,1993, which provided the generic response to the RAls on behalf of the PWR industry, and in addition proposed an integrated program on behalf of the industry. Your submittal of December 11,1999, accomplished the following objectives:
1.
Clarified that only two susceptibility models are currently being adopted by the industry for the assessment of VHP nozzles in the PWR industry.
2.
Confirmed that participating members of the CEOG had opted to use the susceptibility model designed by the Dominion Engineering Company as the basis for ranking the VHP nozzles in CE designed plants.
- 3. Amended the probabilistic ranking histograms to identify the plants which fell into the respective histogram ranking groups.
- 4. Addressed how each of the susceptibility models were benchmarked.
5.
Addressed how each of the susceptibility models would be refined to include plant-specific inspection results.
- 6. Addressed how the variability in product forms, material specifications, and heat treatments used for fabrication of VHP nozzles were addressed in each of the respective susceptibility models.
The initial generic responses to GL 97-01, when taken in context with the information in your response of December 11,1999, provide an acceptable approach for addressing the potential for PWSCC to occur in the VHP nozzles of PWR facilities. The staff, therefore, concludes that the integrated program proposed by NEl for VHP nozzles is acceptable, and that the licensees addressed by the GL may refer to the integrated program as a basis for assessing the postulated occurrence of PWSCC in PWR-design VHP nozzles. It is anticipated that closure of the staff's reviews of the plant-specific responses will be completed in the near-term, and that a NUREG will follow which summarizes the staff's and industry's efforts in addressing this issue.
Sincerely, Jack R. Strosnider, Director Division of Engineering Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Distribution: File Center PDR EMCBRF SCoffin BJElliot JHarold DOCUMENT NAME: G:\MEDOFlf\CRDMGCOL.VyPD OFFICE EMCB:DE f EMG Sh 6 EMQ ;D F_ oo:oE 0:oE NAME JMedoff h/L K ch n _
fnNO RHWessman JRStrosnider DATE 3 //7 /9 ,
3 / / /99 h //9/99 / /99 / /99 OFFICIAL R6 CORD COPY d
1
. l
- 4. description of how the models would be refined in the future to include plant-specific inspection results However, as was the case for the earlier responses to the GL, the staff recommended that the addressees combine their efforts with those of the NEl, the PWROGs, and the Electric Power Research Institute in order to prompt a coordinated, generic response to the RAls.
The staff has received and completed its review ofkbmittal of December 11,1999, which provided the generic response theto the RAls on behalf of the PWR industry Your /submittal December 11,1999, accomplished following objectives: kLI. <t /r< t
- 1. Clarified that only two susceptibility models are currently being adopted by thnNpfry for the assessment of VHP nozzles in the PWR industry.
- 2. Confirmed that participating members of the CEOG had opted to use the susceptibility g model designed by the Dominion Engineering Company as the basis for ranking the r VHP nozzles in CE designed plants.
- 3. Amended the probabilistic ranking histograms to identify the plants which fell into the respective histopram ranking groups,
- 4. Addressed how each of susceptibility models were benchmarked.
- 5. Addressed how each of susceptibility models would be refined to include plant-specific inspection results.
- 6. Addressed how the variability in product forms, material specifications, and heat .
treatments used for fabrication of VHP nozzles were addressed in each of the I s respective susceptibility models.
The initial generic responses to GL 97-01, when taken in context with the information in your j response of December 11,1999, provide an acceptable approach for addressing the potential l for PWSCC to occur in the VHP nozzles of PWR deeegned facilities. The staff therefore !
concludes that yeg integrated program foeM@mmeles is acceptable, and that the licensees addressed by the G L may refer to the i egrated program as a basis for assessing the postulated occurre ice of PWSCC in P R-design VHP nozzles. It is anticipated that closure of the staff's reviews f the plant-specifi responses will be completed in the near-term, and that a NUREG will follo which summarize the staff's and industry's efforts in addressing this issue.
Sincerely, A \ g); by W T Jack R. Str snider, Director Division of Engineering Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commir sion Distribution: File Center POR EMCB RF SCoffin BJElliot JHarold DOCUMENT NAME: G:\MEDOFF\CRDMGCOL.WPD OFFICE EMCB:DE [ EMCB:DE EMCB:DE DD:DE D:DE NAME JMedoff OR KRWichman EJSullivan RHWessman JRStrosnider lDATE ]//7 /99 / /99 / /99 / /99 / /99 OFFICIAL RECORD COPY