ML071970519
| ML071970519 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/13/2007 |
| From: | Junge M Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| Junge, Michael A., ACRS, 415-6855 | |
| References | |
| S00159 | |
| Download: ML071970519 (12) | |
Text
July 13, 2007 MEMORANDUM TO: ACRS Members FROM:
Michael Junge, Senior Staff Engineer /RA/
Technical Support Staff, ACRS
SUBJECT:
CERTIFICATION OF THE MINUTES OF THE ACRS SUBCOMMITTEE MEETING ON THE VERMONT YANKEE LICENSE RENEWAL APPLICATION, JUNE 6, 2007 - ROCKVILLE, MARYLAND The minutes of the subject meeting were certified on July 12, 2007 as the official record of the proceedings of that meeting. A copy of the certified minutes is attached.
Attachment:
As stated cc w/o
Attachment:
F. Gillespie C. Santos S. Duraiswamy
July 3, 2007 MEMORANDUM TO: Mario Bonaca, Chairman ACRS Plant License Renewal Subcommittee FROM:
Michael Junge, Senior Staff Engineer /RA/
Technical Support Staff, ACRS
SUBJECT:
WORKING COPY OF THE MINUTES OF THE ACRS SUBCOMMITTEE MEETING ON THE VERMONT YANKEE LICENSE RENEWAL APPLICATION, JUNE 6, 2007 - ROCKVILLE, MARYLAND A working copy of the minutes for the subject meeting is attached for your review.
Please review and comment on them at your earliest convenience. If you are satisfied with these minutes please sign, date, and return the attached certification letter.
Attachments: Certification Letter Minutes (DRAFT) cc w/o
Attachment:
F. Gillespie C. Santos S. Duraiswamy
MEMORANDUM TO: Michael Junge, Senior Staff Engineer, Technical Support Staff, ACRS FROM:
Mario Bonaca, Chairman ACRS Plant License Renewal Subcommittee
SUBJECT:
CERTIFICATION OF THE MINUTES OF THE ACRS SUBCOMMITTEE MEETING ON THE VERMONT YANKEE LICENSE RENEWAL APPLICATION, JUNE 6, 2007 - ROCKVILLE, MARYLAND I hereby certify, to the best of my knowledge and belief, that the minutes of the subject meeting on June 6, 2007, are an accurate record of the proceedings for that meeting.
/RA/
7-12-2007 Mario Bonaca, Date Plant License Renewal Subcommittee Chairman
1 CERTIFIED: July 12, 2007 ISSUED: July 13, 2007 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS MINUTES OF ACRS PLANT LICENSE RENEWAL SUBCOMMITTEE MEETING VERMONT YANKEE JUNE 6, 2007 ROCKVILLE, MARYLAND On June 6, 2007, the Plant License Renewal Subcommittee held a meeting in Room T2B3, 11545 Rockville Pike, Rockville, Maryland, to review the License Renewal Application (LRA) for the Vermont Yankee Nuclear Power Station (VYNPS) and the associated Safety Evaluation Report (SER).
The meeting was open to the public. Mr. Michael Junge was the Designated Federal Official for this meeting. The meeting convened at 10:30 am and adjourned at 3:31pm on June 6, 2007.
ATTENDEES:
ACRS MEMBERS/STAFF Mario Bonaca, Chairman William Shack, Member Otto Maynard, Member J. Sam Armijo, Member Said Abdel-Kahlik, Member Michael Junge, ACRS Staff John Barton, Consultant NRC STAFF/PRESENTERS J. Rowley, NRR A. Stubbs NRR D. Hoang, NRR D. Reddy, NRR S. Arova, NRR P. Qualls, OCM D. Ashley, NRR P. Kuo, NRR Y. Diaz, NRR L. Lund, NRR F. Saba, NRR J. Ayala, NRR P. Buckberg, NRR T. Le, NRR N. Igbal, NRR C. Sydnor, OPA L. Lois, NRR E. Smith, OEDO J. Davis, NRR K. Howard, RES R. Conte, Region I E. Gettys, NRR B. Rogers, NRR R. Mathew, NRR J. Medoff, NRR E. Davidson, NRR B. Lehman, NRR J. Rycyna, NRR R. Auluck, NRR D. Nguyen, NRR K. Hsu, NRR M. Young, OGC M. Modes, Region I T. Sullivan, Entergy J. Thayer, Entergy J. McCann, Entergy G. Young, Entergy J. Dreyfuss, Entergy N. Rademacher, Entergy D. Mannai, Entergy A. Cox, Entergy M. Metell, Entergy
2 The presentation slides, handouts used during the meeting, and a complete list of attendees are attached to the office copy of the meeting minutes. The presentations to the Subcommittee are summarized below.
Opening Remarks Dr. Bonaca, Chairman of the Plant License Renewal Subcommittee, stated that the purpose of this meeting was to hear presentations by and hold discussions with representatives of the NRC staff and Entergy Nuclear Operations, Inc. (ENO), regarding the LRA submitted by ENO and the associated draft SER prepared by the staff.
The Chairman made a couple of general observations about the VYNPS application. The first was regarding the increasing number of exceptions to GALL. He noted that this is not only an issue for VYNPS, but a recurrent theme. He questioned whether GALL should be updated to be less directive or incorporate alternatives for issues that arent really exceptions. GALL was originally a cooperative effort between industry and the staff, and to see a large number of programs take exceptions to GALL implies something has to be looked at in this program. The second issue was the size of the audit report. It is growing and is almost a duplicate portion of the SER, but not written the same way. The information in the SER may not be in the audit report. He suggested it might be beneficial to mesh the reports together in the future.
Dr. Kuo responded to the Chairmans observations. He stated that the staff had observed the same issues, and in 2005 had updated GALL. The recent reviews have found more exceptions than the staff expected. The staff is working with industry to find a way to reduce the number of exceptions. He stated that with the number of exceptions the staff sees now, there is no reason for GALL to exist. The staff will return to the Committee and provide a status report on the GALL progress. Mr. Kuo also discussed the audit reports. He stated that the staff was going to create a question and answer database. The staff would provide a technical justification similar to the SER to the database, identify the status of each item in the database, and when all items are closed, this report will become the audit report.
Vermont Yankee Nuclear Power Station License Renewal Application Introduction Mr. Gallagher, ENO, introduced Mr. Dreyfuss, ENO as the lead presenter, Mr. Rademacher, Director of Engineering, Mr. Mannai, Licensing Manager, Mr. Cox, License Renewal Team, and Mr. Metell, License Renewal Project Manager.
3 Agenda Mr. Dreyfuss, ENO, discussed the agenda which included a brief description of the site, licensing history, major plant improvements, plant performance, the license renewal project and specific presentations on the Vernon Hydroelectric Station, as well as the Drywell Shell and Torus Shell integrity.
Vermont Yankee Plant Description Mr. Dreyfuss stated the plant is located on the Connecticut River. General Electric was the Nuclear Steam Supply System and Turbine Generator vendor with Ebasco providing the architectural engineering and construction for the plant. It is a BWR-4 with a Mark I Containment. The plant is rated at 1912 MWt with a 650 MW electrical output. The cooling is a hybrid cycle condenser with forced draft cooling towers.
Licensing History and Major Plant Improvements Mr. Dreyfuss described some licensing highlights. The plant received its operating license on March 21, 1972 and the current license expires on March 21, 2012. The plant was acquired by Entergy from Vermont Yankee Nuclear Power Corporation on July 31, 2002. Following the acquisition, a number of substantial capital upgrades and major projects took place including the 20 percent power uprate, dry fuel storage at the facility, as well as the license renewal project.
Mr. Dreyfuss described a number of major plant improvements including Core Spray System Piping Replacement, Mark-I Containment modifications, Recirculation System piping replacement, change over to hydrogen water chemistry in 2003 and several power uprate equipment upgrades such as both high and low pressure turbines.
Recent Plant Performance and Outage Summary Mr. Dreyfuss stated the plant is currently starting up from a re-fueling outage. Prior to the refueling outage, the plant ran 549 continuous days. The power uprate was accomplished during this time period and the unit ran for a year at the higher power.
Mr. Dreyfuss identified and discussed a couple of items of interest from the outage. The steam dryer did not have fatigue indications that had been seen elsewhere in the industry. There were indications identified as Intergranular Stress Corrosion Cracking (IGSCC) which were acceptably dispositioned with the help of General Electric. Another item of interest Mr. Dreyfuss discussed was Flow Accelerated Corrosion (FAC). The FAC inspections were increased by 50% from the pre-uprate number during the outage. Mr. Fitzpatrick, ENO, stated that the inspections were satisfactory and consistent with the analytical modeling for FAC. The
4 enhanced number of inspections will continue through the next couple of fuel cycles to get more data for use in the check-works model.
During the outage, major modifications included replacing a feedwater pump motor, as well as 345 kilovolt breakers.
License Renewal Project Mr. Dreyfuss described the multi-discipline team used in the License Renewal Project. He described the applicants philosophy with respect to the many (>30) exceptions to the GALL.
Mr. Dreyfuss explained that the exceptions were placed into six categories. Mr. Cox, ENO, described the six categories and provided examples of exceptions taken in each category. The categories were 1) an activity not applicable to the plant design, 2) an alternative consistent with approved methods, 3) a program based on a different ASME code edition, 4) a method that was equal to or better than the GALL method, 5) the applicants experience justified an exception, and 6) the GALL method was not feasible.
Mr. Dreyfuss stated that there were several peer reviews, as well as internal reviews conducted on the License Renewal Application. Comments from these sources were resolved prior to submitting the application. He also stated that the License Renewal Commitments would be tracked by and Entergy commitment tracking system and would be added to the FSAR when the renewed license is issued. Mr. Dreyfuss also described the thirty-nine Aging Management Programs (AMR). There are seventeen programs in place without enhancements, thirteen programs will be enhanced and there are nine new programs.
Drywell Shell and Torus Shell Integrity Mr. Dreyfuss summarized the protective features associated with the drywell shell. He stated that the design minimized the potential for undetected water intrusion, that there are diverse methods of prevention and identification of potential water leakage into the air gap, and corrosion potential is minimized since there is no foam or insulation in the air gap. He stated that there have not been any refueling bellows or spent fuel pool liner leakage events.
Additionally he described the inspection program and results from a number of inspections that have been performed on the drywell liner.
Mr. Dreyfuss summarized the torus shell integrity and monitoring. He stated that the Torus condition fully satisfies design requirements, no margins have been lost due to corrosion and that the material condition would be assured by ongoing inspections of the coating and ultrasonic measurements of the shell during the next three refueling outages.
Vernon Hydroelectric Station Mr. Dreyfuss explained the purpose of the Vernon Hydroelectric Station (VHS) is to provide power to VYNPS in a station blackout event. It has 100% redundant cabling with a breaker that
5 can be closed by the control room operators to provide power to the plant. Mr. Dreyfuss described the contractual arrangements and interface with the VHS.
Staff Presentation The presentation by Mr. Rowley, NRR, Mr. Modes, Region I, and Mr. Conte, Region I, provided an overview of the regions inspections during the 2006 refueling outage, and staffs draft SER.
SER Overview The presentation by Mr. Rowley provided an overview of the staffs SER. He described the staffs review activities associate with scoping, screening, aging management, and time-limited aging analysis.
Mr. Rowley stated that the draft SER was issued on March 30, 2007 with no open items and six confirmatory items. The staff issued 85 RAIs and 386 audit questions. The staffs audits and inspections were conducted between April 2006 and May 2007.
Region I Inspections Mr. Modes summarized the scope and results of the inspection the Region performed. The inspection noted a number of weaknesses. Mr. Modes described the weaknesses and provided examples that demonstrated the weaknesses. For example, scoping in the turbine building, the inspectors felt the applicant did not capture how non-safety equipment affects the safety equipment. This issue was corrected. Another example was containment management. The inspection team noted that there were no visual examination acceptance standards, no procedures for monitoring the sandbed region drains and the applicant only had a single point corrosion rate for the torus. These issues were corrected by creating procedures and committing to perform more UT examinations on the torus shell to establish a stronger position for the corrosion rate.
Mr. Modes stated the inspection team concluded that the screening and scoping of non-safety related systems, structures, and components was implemented as required by the rule and the aging management portions of the license renewal activities were conducted as described in the application.
Status of Open Items/Commitments Mr. Rowley stated that the SER with confirmatory items was issued on March 30, 2007 with no open items and six confirmatory items. Mr. Rowley stated that the Region I inspection team provided enough information to close two of the confirmatory items, but four remained open. He stated that the remaining four confirmatory items will be closed soon, the information necessary to close the items has been obtained, but needs to be documented on the docket.
6 Scoping and Screening Mr. Rowley stated that the applicants scoping and screening methodology meets the requirements of 10CFR54.4 and 10 CFR 54.21(a)(1) and that with the resolution of the confirmatory items, the scoping and screening results for systems, structures, and components within scope will be satisfied.
Aging Management Program (AMP)
Mr. Rowley described the staffs evaluation of the AMPs and aging management reviews for VYNPS. He stated that there were 39 AMPs, 29 are existing programs and 10 are new programs. He noted that 3 AMPs were added during the review by the staff.
Mr. Rowley stated that a program of interest was the structures monitoring of the VHS FERC inspection program. This was identified because of concerns over third party status of the VHS.
The aging management of the VHS is being performed by FERC and the VHS owner without participation from VYNPS. References in the AMP are being clarified to show that the applicant is accountable for the monitoring.
Time Limited Aging Analysis (TLAAs)
Mr. Rowley discussed the TLAAs affected by neutron embrittlement. The Reactor Vessel Fluence and Upper-Shelf Energy (USE) were specifically discussed. He stated that an analysis performed by General Electric using an NRC approved methodology indicates the values calculated are within the boundaries for reactor vessel fluence with the incorporation of the power uprate.
Mr. Medoff, NRR, stated the relevant rule for USE is 10CFR50 Appendix G, which requires the USE at end of life be greater than 50 foot pounds. For this applicant the plate criteria is met. If that criteria cannot be met, then the rule requires an equivalent margins analysis be completed.
For the limiting plate and limiting welds, equivalent margins were used and the applicant met that criteria.
Mr. Rowley stated the applicant will either refine the fatigue analyses to demonstrate cumulative usage factors are less than one, and/or manage the aging effects due to fatigue at affected locations by an NRC approved inspection program and/or repair or replace the affected locations, two years prior to entering the period of extended operation. Mr. Rowley stated the staff concluded that the metal fatigue analyses are in compliance with 10CFR54.21(c)(1)(I), (ii) and (iii).
7 Member Comments General Mr. Bartons comments: Mr. Barton provided his views on the SER. He felt that it was not a quality document and did not have good technical justifications for a lot of the positions. He thought the presentation by the applicant was good and presented a good picture of the application and condition of the plant. He felt there were too many exceptions to GALL and it may be worth while to make a revision to GALL. He felt the applicant did a good job categorizing the exceptions and explained very clearly why each exception was taken.
Mr. Maynards comments: Mr. Maynard felt the presentations were very good and informative.
The technical information needed for back up to questions that were asked was readily available. He had two issues that were generic in nature to the License Renewal process. The number of exceptions to GALL may require a revision to GALL or a category could be created that would identify which items were actual exceptions or that they are just slight deviations. He said it would be good to get back to a point where we were dealing with exceptions that are truly exceptions to the methodology.
The other issue Mr. Maynard identified was the number of issues applicants have with identifying proper boundaries. It may be that there isnt enough guidance to applicants, or that each applicants designs or drawings are unique, but there seems to be a number of questions on the boundaries.
Mr. Maynard thought it would be beneficial to have a meeting with the staff on GALL.
Dr. Armijos comments: Dr. Armijo thought a number of the exceptions were borderline technicalities and shouldnt be labeled exceptions if the staff believed they were equivalent or better. He felt better terminology would solve the problem. The exceptions should be limited to issues of substance. He thought VYNPS did a very good job in the selection of replacement materials and that the applicant did a good job assuring the drywell shell and torus shell are in good shape. He thought the commitment made to use hydrogen water chemistry technology to protect their materials was the right way to go. The discussion about fatigue satisfied him in that it can be handled in more than one way and that the applicant is going to take care of the fatigue issue.
Dr. Armijo did not feel comfortable with the explanation as to how an IGSCC could occur in the upper portion of the steam dryer as opposed to a fatigue crack since the water in the region wont be there a long period of time. He felt that the cracks were found after the first cycle of 20 percent power uprate and if formed quickly, that its more a fatigue crack than a stress corrosion crack. But the applicant has done a loose parts analysis and states that it wont come apart.
Dr. Abdel-Khaliks comments: Dr. Abdel-Khalik had nothing to add beyond his colleagues comments. He felt the applicant and staff provided clear presentations.
8 Dr. Shacks comments: Dr. Shack felt that most of the exceptions were fairly trivial. He noted one that was substantive, which was the lack of visual inspections on the ID of the core shroud.
The staff negotiated with the applicant and the inspections will be completed in accordance with BWR VIP 76. He thought this serious exception to GALL was resolved properly.
Chairman Bonacas comments: Chairman Bonaca stated the presentations were very good. He agreed that the exceptions didnt seem to be substantive. He does not want to see GALL become obsolete as to exceptions and he felt that staff and industry should revisit the GALL and put in latitude that is more accepting of a variety of programs.
Chairman Bonaca agreed that the issue of boundaries for scoping is identified in approximately 50 percent of the plants that have come through the License Renewal process. He thought the level of drawings is an issue, but the inspections that occur on site should be able to solve the issue or come to an agreement on the boundaries.
Chairman Bonaca also stated that he was impressed with the conditions in the plant. The measures of the drywell and torus are in good shape and the pictures convey how well the plant is being maintained.
Subcommittee Decisions and Follow-up Actions The Subcommittee Chairman will summarize the discussions at the June 2007 ACRS meeting.
The staff will provide a presentation to the ACRS on issues related to the GALL.
Background Materials Provided to the Committee 1)
Vermont Yankee Nuclear Power Station-License Renewal Application, dated January 27, 2006.
2)
Safety Evaluation Report with Confirmatory Items Related to the License Renewal of Vermont Yankee Nuclear Power Station dated March 2007.
3)
Audit and Review Report for Plant Aging Management Reviews and Programs-Vermont Yankee Nuclear Power Station dated March 30, 2007.
NOTE:
Additional details of this meeting can be obtained from a transcript of this meeting available in the NRC Public Document Room, One White Flint North, 11555 Rockville Pike, Rockville, MD, (301) 415-7000, downloading on the Internet at http://www.nrc.gov/reading-rm/doc-collections/acrs/ can be purchased from Neal R. Gross and Co., 1323 Rhode Island Avenue, NW, Washington, D.C. 20005, (202) 234-4433 (voice), (202) 387-7330 (fax),
nrgross@nealgross.com (e-mail).
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