ML15261A230
| ML15261A230 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/27/1999 |
| From: | Joseph Sebrosky NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9908310171 | |
| Download: ML15261A230 (22) | |
Text
UNITED STATES o
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 27, 1999 LICENSEE:
Duke Energy Corporation (Duke)
FACILITY:
Oconee Nuclear Station, Units 1, 2, and 3
SUBJECT:
SUMMARY
OF MEETING BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION (NRC) STAFF AND DUKE REPRESENTATIVES REGARDING SCOPING FOR THE OCONEE LICENSE RENEWAL APPLICATION On August 18, 1999, representatives of Duke met with the NRC staff at the Oconee site in Seneca, South Carolina to discuss the scoping process used for the license renewal application for Oconee Units 1, 2, and 3. A list of meeting attendees is provided in Enclosure 1.
The NRC staff was at the Oconee site from August 16, 1999, through August 18, 1999, to review material associated with the scoping process: Enclosure 2, which was also attached to the meeting notice, provides background material and the agenda for the staff's review. A public meeting was held at the end of the visit to discuss the staff's observations. As stated in, the staff reviewed 6 events to determine if they agreed with Duke's justification for including or excluding them as design-basis events (DBEs) for the purpose of license renewal.
The following observations summarize the results of the review for the 6 events as discussed during the public meeting.
High Energy Line Break (HELB):
Duke did not consider their actions related to HELB as a DBE for the purposes of license renewal. Duke's position is that Oconee was designed before the HELB concern. Duke stated that they did do additional analysis and installed equipment (e.g., pipe whip restraint, and jet impingement shield) but the staff did not impose any long term controls on this equipment (e.g.,
testing, maintenance, quality assurance). In addition, Duke did not consider HELB as a DBE for any Commission regulations since 1973.1 Because there are no long term controls on the equipment, and because HELB was not considered as a DBE for other Commission regulations, Duke did not consider this as a DBE for license renewal.
The staff believes that because design changes were made to the plant as a result of the HELB concern and if these design changes were relied on in the staffs SER that resolved the issue then HELB should be considered as a DBE for license renewal. The staff also believes that the systems structures and components (SSCs) relied on to mitigate a HELB (e.g., shield, pipe whip Note: Subsequent to the meeting Duke determined that the HELB study was considered when 10 CFR 50.49 was issued. At the time 10 CFR 50.49 was issued, Duke determined that HELB would not create a harsh environment and therefore this event did not impact 10 CFR 50.49 results.,-,,
9908310171 990827 PDR ADOCK 05000269 P
-2 restraint) should be considered to be within scope of license renewal and subject to an aging management review.
As a result of the meeting Duke has an action item to reconsider whether HELB should be a DBE for the purpose of license renewal. It was requested that Duke be prepared to discuss the issue at a management. meeting scheduled for August 27, 1999.
Spent Fuel Pool Coolinq:
Duke does not consider this as a DBE for the purpose of license renewal. Duke stated that they do not rely on the spent fuel pool cooling function in their current licensing basis. Instead Duke relies on maintaining the integrity of the pool (therefore the pressure boundary function of the spent fuel pool cooling system is within scope of license renewal).
Duke also relies on boiling of the spent fuel pool, and time to arrange for makeup to the pool (i.e., arrange an alternate water supply such as a fire truck).
The staff is considering Duke's position. The audit team was concerned that this event may need to be considered a DBE for the purpose of license renewal. The basis for this concern is a spent fuel pool rerack analysis that has as an initial condition that the spent fuel pool is maintained less than 150 degrees F. The only way the temperature can be maintained less than 150 is to rely on the spent fuel pool cooling function. Because the rerack analysis is part of Duke's current licensing basis and because it establishes initial conditions for "normal operation" of the system the spent fuel pool cooling function may need to be considered as a DBE for license renewal.
As a result of the meeting the staff has an action item to review Baltimore Gas and Electric's approach on Calvert Cliffs to determine how the cooling function for the spent fuel pool cooling system was captured. In addition, the staff has an action to determine if a system is required to maintain normal initial conditions should it be considered to be within scope for license renewal.
Loss of Decay Heat Removal (DHR):
Duke does not consider this a DBE for license renewal. Duke does not believe that they are required to consider this a DBE by their interpretation of the license renewal rule. In addition, Duke believes that if it were considered to be a DBE for license renewal that no additional SSCs would be captured because all the SSCs relied on to mitigate this event are required to mitigate other events that are considered as DBEs (e.g., large break LOCA).
The staff acknowledged that additional SSCs would probably not be captured by considering this as a DBE. The staff questioned if current licensing basis commitments (e.g., responses to bulletins, and generic letters) would result in this event being considered as a DBE.
Nevertheless, the staff does not think that it can rely on the results of Duke's existing scoping process. The staff believes that it needs to have confidence that Duke's scoping process is being applied in accordance with the license renewal rule in order to develop a reasonable assurance finding.
-3 Loss of Heating Ventilation and Air Conditioning (HVAC) Cooling to the Control Room:
Duke did not originally consider the cooling function to be within scope of the license renewal rule. Subsequent to the license renewal application, Duke converted to the improved standard technical specifications that changes its current licensing basis regarding the cooling function for the HVAC to the control room. Because of the recent change to the current licensing basis Duke now considers the cooling function to be within scope for license renewal. Therefore, Duke will incorporate this change in their license renewal application update that is due to the staff in the fall 1999 time frame. The staff agrees that the cooling function is within scope of the license renewal rule.
Steam Generator Tube Rupture (SGTR):
This event was reviewed because it was discussed in the scoping inspection report dated May 24, 1999. The Chapter 15 events were reanalyzed recently. Because the analysis for this event was significantly different from the previous analysis, an event mitigation calculation was not performed on it until the reanalysis was complete.
The May 24, 1999 inspection report mentions that Duke is tracking this issue with a problem investigation process corrective action document and the resolution will be reviewed during a future NRC inspection. During the August 16 through 18 audit the staff determined that after the LRA was submitted, the reanalysis was approved by the NRC staff, an event mitigation calculation was performed by Duke, and Duke stated that the results will be included in the annual update to the license renewal application. The audit team found Duke's approach in this area acceptable. The staff stated that it will evaluate the SGTR issue for inclusion in the next inspection report for license renewal that is scheduled to be issued in mid-September.
Fuel Handling Accident:
The staff did not look at this event in detail. Duke considers the event to be a DBE for Oconee and it is included in the scoping methodology for license renewal. The staff performed a limited review of information associated with this event. The staff did not identify any issues associated
- with this event. The staff also stated that if any additional information regarding this event is needed it will inform Duke. contains the slides that Duke presented to the staff during a presentation that discussed Duke's process for scoping events for its license renewal application. The slides are provided as background material for the issue. The staff intends to issue a separate audit report August 27, 1999 that contains more details for the above events. A draft of this meeting summary was provided to Duke to allow them the opportunity to comment on the summary prior to issuance.
original signed by Joseph M. Sebrosky, Project Manager License Renewal and Standardization Branch Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosures:
As stated (3) cc w/encls: See next page DISTRIBUTION: See next page DOCUMENT NAME:G:\\RLSB\\SEBROSKY\\8-18 SUM.WPD OFFICE LA RLSB/DRIP:PM IQMB/DIPM RLSB/DRIP:BC NAME EHylton $
JSebrosky TQuay ClGrime I
DATE T 0/99 6/99
/ -1499
/99 OFFICIAL RECORD COPY
Oconee Nuclear Station (License Renewal) cc:
Mr. J. E. Burchfield Ms. Lisa F. Vaughn Compliance Manager Duke Energy Corporation Duke Energy Corporation 422 South Church Street Oconee Nuclear Site Mail Stop PB-05E P. 0. Box 1439 Charlotte, North Carolina 28201-1006 Seneca, South Carolina 29679 Anne W. Cottingham, Esquire Ms. Karen E. Long Winston and Strawn Assistant Attorney General 1400 L Street, NW.
North Carolina Department of Justice Washington, DC 20005 P. 0. Box 629 Raleigh, North Carolina 27602 Mr. Rick N. Edwards Framatome Technologies L. A. Keller Suite 525 Manager - Nuclear Regulatory Licensing 1700 Rockville Pike Duke Energy Corporation Rockville, Maryland 20852-1631
'526 South Church Street Charlotte, North Carolina 28201-1006 Manager, LIS NUS Corporation Mr. Richard M. Fry, Director 2650 McCormick Drive, 3rd Floor Division of Radiation Protection Clearwater, Florida 34619-1035 North Carolina Department of Environment, Health, and Senior Resident Inspector Natural Resources U. S. Nuclear Regulatory Commission 3825 Barrett Drive 7812B Rochester Highway Raleigh, North Carolina 27609-7721 Seneca, South Carolina 29672 Gregory D. Robison Regional Administrator, Region II Duke Energy Corporation U. S. Nuclear Regulatory Commission Mail Stop EC-12R Atlanta Federal Center P. 0. Box 1006 61 Forsyth Street, SW, Suite 23T85 Charlotte, North Carolina 28201-1006 Atlanta, Georgia 30303 Robert L. Gill, Jr.
Virgil R. Autry, Director Duke Energy Corporation Division of Radioactive Waste Management Mail Stop EC-12R Bureau of Land and Waste Management P. 0. Box 1006 Department of Health and Charlotte, North Carolina 28201-1006 Environmental Control RLGILL@DUKE-ENERGY.COM 2600 Bull Street Columbia, South Carolina 29201-1708 Douglas J. Walters Nuclear Energy Institute County Supervisor of Oconee County 1776 I Street, NW Walhalla, South Carolina 29621 Suite 400 Washington, DC 20006-3708 W. R. McCollum, Jr., Vice President DJW@NEI.ORG Oconee Site Duke Energy Corporation Chattooga River Watershed Coalition P. O. Box 1439 P. O. Box 2006 Seneca, SC 29679 Clayton, GA 30525
ATTENDANCE LIST AUGUST 18, 1999, NRC MEETING WITH DUKE REGARDING OCONEE SCOPING NAME ORGANIZATION William R. McCollum, Jr.
Duke Bill Foster Duke Larry Nicholson Duke Steve Nader Duke Rounette Nader Duke Greg Robison Duke Robert Gill Duke Dayle Stewart Duke Tom Shiel Duke Ted Quay NRR/DIPM/IQMB Chris Gratton NRR/DSSA/SPLB Kerry Landis NRC/Region II Caudle Julian NRC/Region II Scott Freeman NRC/Resident David LaBarge NRR/DLPM Chris Grimes NRR/DRIP/RLSB Joe Sebrosky NRR/DRIP/RLSB Rick Nelson INPO Ken Kasper NUS Information Services
August 16 through 18, 1999, Audit Background
Purpose:
The purpose of the audit is to attempt to resolve Oconee Nuclear Station (ONS) safety evaluation report (SER) open item 2.1.3.1-1. An agenda is attached for the audit.
Background:
The staff issued the SER related to the license renewal of ONS Units 1, 2, and 3 on June 16, 1999. Section 2.1 of the SER discusses the staff's assessment of Duke's methodology for identifying structures and components subject to an aging management review. One aspect of the staff's review was the scoping process that Duke used to comply with the requirements of 10 CFR 54.4(a)(1) and 10 CFR 54.4(a)(2). The NRC originally questioned aspects of Duke's scoping process in request for additional information (RAI) 2.2-6 that Duke responded to in a February 17, 1999, letter. A technical meeting was held on March 11, 1999, to further discuss the scoping issue. The meeting resulted in a revision to Duke's response to RAI 2.2-6 dated March 18, 1999, that provided an explanation of the scoping events set used for the license renewal mechanical scoping. Following the revision, the scoping issue remained open, leading to a May 11, 1999, management meeting to discuss the issue. In addition to the correspondence and meetings noted above, the NRC performed an inspection of Duke's scoping and screening process at Oconee from April 26 - 30, 1999. The inspection report 50-269/99-11, 50-270/99-11, and 50-287/99-11, dated May 24, 1999, also contains information related to this issue.
The May 11, 1999, management meeting resulted in action items that were carried forth as open item 2.1.3.1-1 in the SER. Specifically, the SER contains the following related to this open item:
The applicant agreed to supplement its response to the staff's request for additional information (RAI) 2.2-6, to include a description of the process used to identify events for ONS license renewal scoping consistent with the presentation that was given to the staff.
The applicant agreed to provide an explanation as to how the 26 events identified during the meeting are sufficient to satisfy 10 CFR 54.4(a)(1) and 54.4(a)(2). This is Open Item 2.1.3.1-1.
- .Once the information identified in item 1 above is provided, the staff will determine whether additional inspection activities will be needed to verify that there is reasonable assurance that the Oconee systems, structures and components that are within scope of the license renewal rule have been captured by the applicant's process. This is part of open item 2.1.3.1-1.
By letter dated June 22, 1999, Duke responded to the first part of open item 2.1.3.1-1. The staff's preliminary assessment of Duke's response is that it resolves the first part of open item 2.1.3.1-1. (The staff will present its final conclusion on this part of the issue in an update to the SER).
-2 In accordance with the second part of open item 2.1.3.1-1, the staff has determined that an additional audit is needed to resolve the issue. In the March 11, 1999, meeting Duke stated that there are 26 events that were considered scoping events that were used in the mechanical scoping area. Duke also stated that it reviewed an additional 32 events for possible inclusion into the set of scoping events. The staff's intention is to probe the additional 32 events that were considered for possible inclusion into the scoping events set.
Because the 26 scoping events that Duke used only considered those design-basis events identified in the Oconee updated final safety analysis report Chapter 15 and a limited number of other events, it is unclear as to whether all the design-basis events as required under 10 CFR 54.4(a)(1) and defined in 10 CFR 50.49(b)(1) have been identified. Furthermore, since the implementation of the applicant's scoping methodology may not have identified all the systems structures and components required in accordance with 10 CFR 54.4(a)(1), the potential exists for this concern to also affect the results of the scoping activities for the non-safety-related systems structures and components required under 10 CFR 54.4(a)(2).
The staff will review Duke's justification for the following events: pipe rupture, loss of decay heat removal, updated steam generator tube rupture analysis, loss of spent fuel pool cooling, loss of heating ventilation and air conditioning (HVAC) to the control room, and fuel handling accident.
The first three events were identified during the April 26 - 30 inspection at the site. The fourth event, loss of spent fuel pool cooling, was also identified during the April 26 - 30 inspection and SER open item 2.2.3-1 is related to this issue. The fifth issue, loss of HVAC to the control room is related to SER open item 2.2.3.4.3.2.1-1. The staff identified the fuel handling accident because of concerns related to the cabling associated with the fuel handling bridges. Depending on the results of the review associated with the above 6 events the staff may expand its review.
In determining whether any of the events should have been considered the staff expects to use guidance associated with generic license renewal issue 98-0082 "Scoping Guidance." The staff expects that its position on the issue will be issued to the Nuclear Energy Institute prior to the audit.
ONS Design Basis Events
Background
Five year project to:
- clarify design basis issues
- enhance level of documentation
- Confirm definitions of two key terms
- safety-related
-design basis events
ONS Design Basis Events Problem Statement
- Typical NRC regulations state,
".. equipment used. to mitigate the consequences of design basis events"
ONS Design Basis Events Simple Answer Chapter 15 of the Oconee UFSAR states, "This section details the expected response of the plant to the spectrum of transients and accidents which constitute the design basis events."
ONS Design Basis Events Simple Answer (con't)
August 3, 1995 SER* states, "Chapter 15 of the FSAR details the expected response of the plant to the spectrum of transients and accidents which constitute the design basis events."
- *SER on our updated response to GL83-28 which clarifies QA-1 classifications
ONS Design Basis Events Validation
- Historical Research
- Understand the differences between DBEs and Design Criteria
- how was DBE originally applied at ONS
- how DBE began to show up in NRC correspondence
- defined in 50.49 (EQ rule)
- results of this study captured in DBE white paper and DBE DBD
ONS Design Basis Events Validation
- Expert Panel Approach
-reviewed results of historical research to confirm conclusions
ONS Design Basis Events Conclusion
- Chapter 15 defines Design Basis Events
- Historical research confirmed that the list is correct
- Expert panel validated the conclusions
ONS Design Basis Events Current Position Chapter 15 lists ONS Design Basis Events
- Risk-informed decision making was used to voluntarily expand the list
- Additional events
- natural phenomena
- post-TMI emergency feedwater design basis scenarios
- SSF-mitigated Turbine Building Flood event
ONS Design Basis Events Current Position DBEs plus additional events constitute the events used in Step 1 of the 10 CFR 54.4(a)(1) and (a)(2) LR scoping methodology
License Renewal Mechanical Scoping Methodology August 17, 1999
Mechanical Scoping Methodology Step 1:
Identify all mechanical flowpaths required to remain functional for successful design basis event mitigation
Mechanical Scoping Methodology Step 2:
Identify all fluid pressure boundaries whose loss of fluid pressure boundary could impact the mechanical functions identified in Step #1
Mechanical Scoping Methodology Step 3:
Identify all portions of mechanical systems whose loss of pressure boundary or structural integrity would physically interfere with the function of any essential system and component.
Mechanical Scoping Methodology Step 4:
Identify all portions of mechanical systems designated as safety-related or seismic related piping or components that do not meet the criteria of 10 CFR 54.4(a)(1) or
( a)(2).