ML11293A514
| ML11293A514 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/28/2011 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of License Renewal |
| References | |
| Download: ML11293A514 (5) | |
Text
1 Davis-BesseNPEm Resource From:
CuadradoDeJesus, Samuel Sent:
Wednesday, September 28, 2011 2:56 PM To:
dorts@firstenergycorp.com Cc:
custerc@firstenergycorp.com; Davis-BesseHearingFile Resource
Subject:
FW: New RAIs for DB LRA Section 4.7.5.2 TLAA (SG shell flaw evaluations)
Attachments:
Davis-Besse LRA Supplemental RAIs for 4.7.5.docx Steve:
Attached is a draft RAI. Ill schedule the teleconference for tomorrow afternoon. Well discuss this RAI and the other two I sent previously also on section 4.
- Regards, Samuel Cuadrado de Jesús Project Manager Projects Branch 1 Division of License Renewal U.S. Nuclear Regulatory Commission Phone: 301-415-2946 Samuel.CuadradoDeJesus@nrc.gov
Hearing Identifier:
Davis_BesseLicenseRenewal_Saf_NonPublic Email Number:
1553 Mail Envelope Properties (377CB97DD54F0F4FAAC7E9FD88BCA6D0805095FA3B)
Subject:
FW: New RAIs for DB LRA Section 4.7.5.2 TLAA (SG shell flaw evaluations)
Sent Date:
9/28/2011 2:55:39 PM Received Date:
9/28/2011 2:55:42 PM From:
CuadradoDeJesus, Samuel Created By:
Samuel.CuadradoDeJesus@nrc.gov Recipients:
"custerc@firstenergycorp.com" <custerc@firstenergycorp.com>
Tracking Status: None "Davis-BesseHearingFile Resource" <Davis-BesseHearingFile.Resource@nrc.gov>
Tracking Status: None "dorts@firstenergycorp.com" <dorts@firstenergycorp.com>
Tracking Status: None Post Office:
HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 465 9/28/2011 2:55:42 PM Davis-Besse LRA Supplemental RAIs for 4.7.5.docx 25723 Options Priority:
Standard Return Notification:
No Reply Requested:
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Recipients Received:
REQUEST FOR ADDITIONAL INFORMATION LICENSE RENEWAL APPLICATION, SECTION 4.7.5.2 TIME-LIMITED AGING ANALYSES DAVIS-BESSE NUCLEAR POWER STATION FIRST ENERGY NUCLEAR OPERATING COMPANY DOCKET NO. 50-346 LRA Section 4.7.5.2 - Steam Generator 1-2 Flaw Evaluations Supplemental RAI 4.7.5.2-1
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Background===
LRA Section 4.7.5.2 addresses the TLAA related to the Steam Generator 1-2 flaw evaluations.
LRA Section 4.7.5.2 states that the subject flaws were analytically evaluated using the ASME Code,Section XI, IWB-3612 acceptance criteria. LRA Section 4.7.5.2 further states that the IWB-3612 analysis of the subject flaws determined that the steam generator shell components containing the flaws would remain acceptable for continued service during the period of extended operation, accounting for flaw growth due to fatigue based on 240 heat-up and cool-down cycles.
By letter dated March 17, 2011 (ADAMS Accession No. ML110680172) the NRC staff submitted a request for additional information (RAI) concerning the plant-specific time-limited aging analyses (TLAAs) in the Davis-Besse License Renewal Application (LRA), Sections 4.7.4, 4.7.5.1, and 4.7.5.2. RAI Question No. 4.7.5.2-1 (RAI 4.7.5.2-1) was issued to request clarification on a number of issues concerning the subject steam generator shell flaws and the ASME Code,Section XI, IWB-3612 analytical evaluations of these flaws.
In RAI 4.7.5.2-1, part (b), the staff requested that the applicant state whether the subject flaws were found to be the result of service-induced degradation or fabrication defects. In RAI 4.7.5.2-1, part (e) the staff requested that the applicant state whether the flaw dimensions have increased since discovery in 1988. The staff also requested that, if the flaw dimensions have increased, the applicant state whether the subject flaws were re-analyzed in accordance with ASME Code,Section XI, IWB-3612 requirements based on the new flaw dimensions. In RAI 4.7.5.2-1, part (g), the staff requested that the applicant provide references for all reports documenting IWB-3612 analytical evaluations of the subject flaws.
Issue By letter dated April 15, 2011, the applicant submitted its responses to the staffs RAIs. In its response to RAI 4.5.2.1, part (b), the applicant stated that the subject flaws were analyzed in accordance with IWB-3612, as required by the ASME [Code],Section XI acceptance standards, and found to be acceptable for continued operation. The staff reviewed the applicants
response to RAI 4.7.5.2-1, part (b) and noted that the applicant did not state whether the subject flaws were determined to be service-induced or caused by fabrication.
In its response to RAI 4.7.5.2-1, part (e), the applicant stated that [t]he subject components were reexamined during Cycle 6 (year 1990) and no flaw growth was noted. The subject components, with the exception of the W axis longitudinal seam weld intersection with the shell to lower tubesheet weld, were also reexamined during Cycle 7 (year 1991) and no flaw growth was noted. The staff reviewed the applicants response to RAI 4.7.5.2-1, part (e), and noted that the RAI response only stated that no flaw growth was noted during the ASME Code, Section IWC-2420(b)-required successive inspections performed in 1990 and the subsequent inspections performed in 1991. The staff noted that the applicant did not state whether any flaw growth was noted for the subject components as a result of any examinations performed on the flawed regions after 1991.
In its response to RAI 4.7.5.2-1, part (g), the applicant stated that the subject flaw evaluations are documented in the following Babcock & Wilcox (B&W) Reports from 1988:
- 1. Report No. 32-1172294-00, Davis-Besse 1 SG Flaw Evaluation, dated June 9, 1988
- 2. Report No. 32-1172294-01, Davis-Besse 1 SG Flaw Evaluation, dated July 18, 1988
- 3. Report No. 32-1172523-00, DB-1 SG Flaw Evaluation, dated July 18, 1988 The above flaw evaluation reports were provided in an enclosure to the April 15, 2011 RAI response. These flaw evaluation reports reference the 1977 Edition of the ASME Code,Section XI, IWB-3612 analytical acceptance standard. The flaw evaluation report summaries state that the subject flaws were found to be acceptable, in accordance with the ASME Code,Section XI, IWB-3612 analytical acceptance standard.
In reviewing the above flaw evaluation reports, the staff determined that the subject flaw evaluations were only performed for normal conditions, and only demonstrated acceptability based on the analytical acceptance criterion for normal (including upset and test) operating conditions, as specified in the ASME Code,Section XI, IWB-3612, paragraph (a). The staff determined that the applicant had not specifically evaluated the subject flaws for emergency and faulted conditions, as required by the 1977 Edition of the ASME Code,Section XI, IWB-3612, paragraph (b).
Request Based on the above, the staff requests that the applicant provide the following information concerning the subject steam generator flaws and the analytical evaluations performed for these flaws:
- a. Taking into consideration the steam generator shell materials containing the flaws, the secondary side water and steam environment, and the secondary side thermal and pressure stresses to which these shell components are subjected, please state whether
any of the surface-breaking indications were believed to have been caused by stress corrosion cracking, or any other service-induced aging effect.
- b. For any inservice examinations performed on the flawed regions of the steam generator shell after 1991, in particular the examinations performed for the steam generator X/Y axis outlet nozzle to shell weld and the lower tubesheet to shell weld during the first and second periods of the third 10-year ISI interval, please state whether these examinations detected any increase in the flaw dimensions, relative to the 1988 flaw dimensions. (The staff notes that any measured increase in flaw dimensions would likely invalidate the analyses performed in the 1988 flaw evaluation reports.)
- c. Please state whether the subject flaws were analyzed for emergency and faulted conditions, as required by the ASME Code,Section XI, IWB-3612, paragraph (b). If the subject flaws were analyzed for emergency and faulted conditions, as required by IWB-3612, paragraph (b), please provide the flaw analyses for these conditions, or explain how the IWB-3612, paragraph (a) analyses, as documented in the 1988 flaw evaluation reports, for normal, upset, and test conditions, would bound the flaw analyses for emergency and faulted conditions. If the subject flaws were not analyzed for emergency and faulted conditions, please provide these analyses, as required by IWB-3612, paragraph (b).