ML20210P519
| ML20210P519 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/11/1999 |
| From: | Kim T NRC (Affiliation Not Assigned) |
| To: | Richard Anderson NORTHERN STATES POWER CO. |
| References | |
| GL-92-01, TAC-MA5920, TAC-MA5921, NUDOCS 9908130023 | |
| Download: ML20210P519 (5) | |
Text
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. ~..,k UNITED STATES f
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August 11, 1999 8
WASHINGTON, D.C. 30seH001
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Mr. Roger O. Anderson, Director Nuclear Energy Engineering Northem States Power Company 414 Nicollet Mall Minneapolis, MN 55401
SUBJECT:
PRAIRIE ISLAND NUCLEAR GENERATING PLANTS, UN!T 1 AND 2 -
PLANT-SPECIFIC FOLLOW-UP TO GENERIC LETTER 92-01, REVISION 1, SUPPLEMENT 1, " REACTOR VESSEL STRUCTURAL INTEGRITY" (TAC NOS.
MA5920 AND MA5921)
Dear Mr. Anderson:
On May 19,1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter 92-01, Revision 1, Supplement 1 (GL 92-01, Rev.1, Supp.1), " Reactor Vessel Structural Integrity," to holders of nuclear operating licenses. In issuing the GL the staff required addressees of the GL to:
(1) identify, collect and report any new data pertinent to the analysis of structural integrity of the reactor pressure vessels (RPVs) at their nuclear plants, and (2) assess the impact of that data on their RPV integrity analyses relative to the requirements of Sections 50.60 and 50.61 to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50.60 and 10 CFR 50.61), and to the requirements of Appendices G and H to Part 50 of Title 10 of the Code of Federa/ Regulations (Appendices G and H to 10 CFR Part 50).
On August 17 and November 17,1995, you submitted your responses to GL 92-01, Rev.1, Supp.1, in which you confirmed that the structural integrity assessments for the Prairie Island Nuclear Generating Plant (PINGP) submitted in 1992 as a response to GL 92-01, Rev.1, remain unchanged. The staff evaluated the responses to GL 92-01, Rev.1, Supp.1, and provided its conclusion relative to NSP's responses on October 28,1996. Since then, however, the Combustion Engineering (CE) Owners Group and the Babcock and Wilcox (B&W) Owners Group have each submitted additional data regarding the alloying chemistries of belt-line welds in CE and B&W fabricated vessels. The additional alloying data were submitted in Topical Reports CE NPSD-1039, Revision 2, CE NPSD-1119, Revision 1 for CE fabricated RPV welds, and BAW-2325, Revision 1 for B&W fabricated RPV welds. As a result of the efforts by CE and B&W, the staff determined that additional infnrmation was necessary relative to the structural integrity assessments for all operating plants.
4n mid-1998, the staff issued a request for additional information (RAI) to all owners group plants in regard to the alloying chemistries of belt-line welds, the assessment of surveillance data, 8^
pressure-temperature (P-T) limits, and pressurized thermal shock (PTS) assessments for their plants. 'In the RAI, the staff requested the licensees to reassess the alloying chemistries for the 1
9908130023 990811 PDR ADOCK 05000282
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i R.O. Anderson a belt-line welds and surveillance welds of their RPV vessels relative to the chemistries provided in the topical reports mentioned above, and provide the impact of any changes to the best-estimate chemistries for the RPV belt-line welds on the structural integrity assessments for their vessels relative to the requirements of 10 CFR 50.60,10 CFR 50.61, and Appendices G and H to 10 CFR Part 50, as applicable to the licensing bases for their plants. For PINGP, which is not a member of any owners group, no RAI was issued, but a telephone conference was conducted in 1998. During the conference, the NSP informed the staff that NSP found minor errors in submittals for GL 92-01, Rev.1, and was conducting a comprehensive review of all submittals related to GL 92-01, Rev.1. Please confirm our understanding that you plan to submit the results of this review within the next three months.
As a result of the staff's review of your responses to GL 92-01, Revision 1, GL 92-01, Rev.1, Supp.1, and the Supp.1 RAI, the staff has revised the information in the Reactor Vessel Integrity Database (RVID) and is releasing it as RVID Version 2. It should be noted that there are some variations in the data inputted by the staff, and the corresponding values reponed in the responses to the GL 92-01, Rev.1, Supp.1. The deviations between the data are explained in the reference sections for each Unit, or the individual component screen notes (i.e., each forging, plate, and weld has a specific area for notes which is a new feature of the database).
They are summarized as follows:
]
In your response to GL 92-01 (dated July 6,1992), you used Position 1.2 (no surveillance data) of RG 1.99, Rev. 2 to arrive at a upper shelf energy (USE) drop of 42% for the limiting weld of Prairie Island Unit 2 RPV regardless of the fact that the surveillance data are available for this weld. You then conservatively applied this USE decrease to all belt-line materials for both Units.
To determine the percentage drop in USE, the staff used Position 1.2 of RG 1.99, Rev. 2 for materials not having surveillance data, and Position 2.2 of RG 1.99, Rev. 2 for materials having surveillance data. Your method of assuming a 42% drop in USE is conservative for all belt-line materials and is therefore, acceptable. However, the RVID is programmed to calculate the percentage drop in USE in accordance with the methodology in RG 1.99, Rev. 2.
For Unit 2, the unirradiated RTer data in WCAP-14638, Rev. 2 (February 1998) for the three old belt-line materials were not implemented in the RVID because more conservative unirradiated RTer values from the original Creusot-Loire test data were reported in your response (November 24,1993) to staff's RAI and in the response (May 19,1994) to the NRC closeout letter for GL 92-01, Rev.1.
We recommend that you review the revised RVID data for Prairie Island. If the staff does not receive comments by September 1,1999, we will assume that the data entered into the RVID are acceptable for your plant.
L*
R.O. Anderson,
The new database diskettes are posted on the world-wide-web at a location which is linked to the NRC home page (http://www.nrc. gov /NRR/RVID/index.html). Future submittals on P-T limits, PTS, or USE should reference the most current information.
The staff appreciates your efforts in regard to this matter.
Sincerely, Tae Kim, Senior Project Manager, Section i Project Directorate ill Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306 cc: See next page o
u.
R.O. Anderson August 11, 1999 The new database diskettes are posted on the world-wide-web at a location which is linked to the NRC home page (http://www.nrc. gov /NRR/RVID/index.html). Future submittals on P-T limits, PTS, or USE should reference the most current information.
The staff appreciates your efforts in regard to this matter,
' Sincerely, (Original signed by)
Tae Kim, Senior Project Manager, Section 1 Project Directorate lli Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306 cc: ' See next page DISTRIBUTION Docket File
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,o, Mr. Roger O. Anderson, Director Prairie Island Nuclear Generating Northern States Power Company Plant ec:
J. E. Silberg, Esquire Shaw, Pittman, Potts and Trowbridge Site Licensing 2300 N Street, N. W.
Prairie Island Nuclear Generating Washington DC 20037 Plant Northern States Pcwer Company Plant Manager 1717 Wakonade Drive East Prairie Island Nuclear Generating Welch, Minnesota 55089 Plant Northern States Power Company Tribal Counci!
1717 Wakonade Drive East Prairie Island Indian Community Welch, Minnesota 55089 ATTN: Environmental Department 5636 Sturgeon Lake Road Adonis A. Nebiett Welch, Minnesota 55089 Assistant Attorney General Office of the Attorney General Site General Manager 455 Minnesota Street Prairie Island Nuclear Generating Suite 900 Plant St. Paul, Minnesota 55101-2127 Northern States Power Company 1717 Wakonade Drive East U.S. Nuclear Regulatory Commission Welch, Minnesota 55089 Resident inspector's Office 1719 Wakonade Drive East Welch, Minnesota 55089-9642 Regional Administrator, Region lli U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Mr. Stephen Bloom, Administrator Goodhue County Courthouse Box 408 Red Wing, Minnesota 55066-0408 Commissioner Department of Public Service 121 Seventh Place East Suite 200 St. Paul, Minnesota 55101-2145 Apri:1999