ML061080126
| ML061080126 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/25/2006 |
| From: | Shawn Campbell Plant Licensing Branch III-2 |
| To: | Bezilla M FirstEnergy Nuclear Operating Co |
| Stephen Cambell, LPL3-2, X1486 | |
| References | |
| TAC MC5661 | |
| Download: ML061080126 (9) | |
Text
May 25, 2006 Mr. Mark B. Bezilla Vice President - Nuclear FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station Mail Stop A-DB-3080 5501 North State Route 2 Oak Harbor, OH 43449-9760
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO TORNADO MISSILE PROTECTION (TAC NO. MC5661)
Dear Mr. Bezilla:
By letter to the Nuclear Regulatory Commission (NRC) dated January 11, 2005, FirstEnergy Nuclear Operating Company submitted a request for approval to credit the use of the tornado missile (TORMIS) computer code in determining whether or not it is necessary to protect a number of structures, systems, and components from tornado generated missiles at the Davis-Besse Nuclear Power Station, Unit 1.
The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on April 13, 2006, it was agreed that you would provide a response 60 days from the date of this letter.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1486.
Sincerely,
/RA/
Stephen J. Campbell, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-346
Enclosure:
Request for Additional Information cc w/encl: See next page
Mr. Mark B. Bezilla May 25, 2006 Vice President - Nuclear FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station Mail Stop A-DB-3080 5501 North State Route 2 Oak Harbor, OH 43449-9760
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO TORNADO MISSILE PROTECTION (TAC NO. MC5661)
Dear Mr. Bezilla:
By letter to the Nuclear Regulatory Commission (NRC) dated January 11, 2005, FirstEnergy Nuclear Operating Company submitted a request for approval to credit the use of the tornado missile (TORMIS) computer code in determining whether or not it is necessary to protect a number of structures, systems, and components from tornado generated missiles at the Davis-Besse Nuclear Power Station, Unit 1.
The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on April 13, 2006, it was agreed that you would provide a response 60 days from the date of this letter.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1486.
Sincerely,
/RA/
Stephen J. Campbell, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-346
Enclosure:
Request for Additional Information cc w/encl: See next page DISTRIBUTION:
PUBLIC LPL3-2 R/F RidsNrrDorlLpl3-2 RidsNrrPMSCampbell RidsNrrLADClarke RidsAcrsAcnwMailCenter RidsOgcRp RidsRgn3MailCenter RidsNrrDssSbpb RidsNrrDssDpr JTatum, DSS ADAMS Accession Number: ML061080126 OFFICE LPL3-2/PM LPL3-2/LA DSS/SBPB/BC(A)
LPL3-2/BC NAME SCampbell:ca DClarke SJones DCollins DATE 05/25/06 05/25/06 05/25/06 05/25/06 OFFICIAL RECORD COPY
ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 DOCKET NO. 50-346 By letter dated January 11, 2005, FirstEnergy Nuclear Operating Company (the licensee) requested Nuclear Regulatory Commission (NRC) approval to credit using Electric Power Research Institute (EPRI) computer code, Tornado Missiles (TORMIS), in determining whether or not it is necessary to protect a number of structures, systems, and components (SSCs) from tornado generated missiles at the Davis-Besse Nuclear Power Station (Davis-Besse). On October 26, 1983, the NRC staff issued, Safety Evaluation (SE) of an Electric Power Research Institute (EPRI) Topical Reports Concerning Tornado Probabilistic Risk Assessment Methodology, approving the use of TORMIS for certain limited applications and identified specific information that should be submitted when requesting NRC approval for using TORMIS. Based upon a review of the licensees request, the following additional information is required:
1.
The October 26, 1983, TORMIS SE issued by the NRC specified that data on tornado characteristics should be employed for both broad regions and small areas around the site, and that the most conservative values should be used in the risk analysis.
(a)
With respect to tornado frequency, the Updated Safety Analysis Report (USAR) value of 6.3 x 10-4 per year is proposed as the more conservative value compared to the estimate for the broader region defined by WASH-1300, Technical Basis for Interim Regional Tornado Criteria, (NRC Region 1).
The following additional information is required in order to demonstrate that the selected frequency estimate meets Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion 2, Design bases for protection against natural phenomena, for SSCs important to safety is designed to withstand the effects of a natural phenomenon such as a tornado:
(i)
Explain how a tornado frequency of 4.25 x 10-4 per year was determined based upon the NRC Region 1 tornado data. (RAI Category: 2.b.)
(ii)
The TORMIS methodology defines four broad regions, A through D, and Davis-Besse is located on the border between Regions A and B.
Regions A and B are a more discrete partitioning of Region 1. Determine the tornado frequency for Davis-Besse for both Region A and Region B, and explain how these values were calculated. (RAI Category: 2.b.)
(iii)
The response that was provided to Item 1 of the October 26, 1983, TORMIS SE regarding input parameters indicates that the annual probability of a tornado will be determined for the Fujita wind speeds using regional data available in TORMIS for NRC Tornado Region 1; and that the more conservative of these two values (the other value being the USAR tornado frequency) will be utilized in the Davis-Besse analysis.
Since Regions A and B are a discrete partitioning of a broad area, the analysis over a broader region (Region 1) could result in different strike probabilities. Explain how this analysis differs from the NRC Region 1 tornado frequency estimate and, to assure that the most conservative value is used, perform this analysis for TORMIS Regions A and B, and for the local site area described in the USAR. Provide the results of these analyses, including an explanation of how these values were calculated. (RAI Category: 2.a.)
(b)
Aside from the tornado frequency estimates discussed above, explain how the most conservative values will be determined for the tornado characteristics that are used in TORMIS based upon regional (WASH-1300 and TORMIS) and local tornado data, including a discussion of how more recent tornado data that is not reflected in TORMIS will be accounted for.
Note that the use of values for tornado characteristics that are not the most conservative based upon the available data must be identified and justification provided for NRC review and approval. (RAI Category: 2.b.)
2.
Describe how the exposed areas of unprotected SSCs will be determined to assure conservative results. (RAI Category: 2.b.)
3.
In the licensees request dated January 11, 2005, the licensee referenced NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants, Section 2.2.3, Revision 2.Section II, Acceptance Criteria, states that the expected rate of exposures in excess of 10 CFR Part 100, Reactor Site Criteria, guidelines of approximately 10-6 per year is acceptable if, when combined with reasonable quantitative arguments, the realistic probability can be shown to be lower.
The proposed change indicates that a tornado missile strike on the limited portion of a system or component that is exposed is assumed to result in a radioactive release that exceeds the 10 CFR Part 100 guidelines, rather than performing specific evaluations as to whether the strike can actually cause damage and releases. Confirm that this logic will apply to all SSCs that are listed in proposed USAR Table 3.5-3, TORMIS Analysis - Essential Safe Shutdown System Tornado Missile Targets, including (for example) the auxiliary building roll up and man doors, auxiliary building emergency diesel generator roof, auxiliary building roof penetrations, and auxiliary building roof drains. Also, revise the USAR to include this clarification. (RAI Category: 2.a.)
4.
The response to the fourth item of the TORMIS SE states that the results of a sensitivity study indicates that the probability values are not significantly adversely impacted by an increase in missile population. Discuss the results of this sensitivity analysis, including the basis for the conclusion that was reached. (Category: 2.c.)
5.
The Technical Analysis section of the proposed change indicates that upon NRC approval, existing plant conditions, as well as future changes to the facility, could be evaluated using TORMIS. However, the TORMIS SE stated that the use of TORMIS should be limited to the evaluation of specific plant features where additional costly tornado missile protective barriers or alternative systems are under consideration.
Therefore, in order to assure that the use of TORMIS will be consistent with the position that was stated in the TORMIS SE, confirm that: a) TORMIS will not be used to temporarily or permanently eliminate existing barriers that are credited for providing tornado missile protection; b) its use will be limited to demonstrating adequate protection for existing SSCs that were originally required to be protected from tornado missiles in accordance with the plant design basis but due to some oversight, are not adequately protected; and c) identify the specific criteria that will be used for future applications of TORMIS in determining whether or not modifications that are required for protecting SSCs from tornado missiles are too costly such that the use of TORMIS is justified consistent with NRC approval of the TORMIS methodology. Also, revise the USAR to include this clarification. (RAI Category: 3.h.)
RAI CATEGORIES (Select only one, most dominant category for each RAI question) 1.
More information is needed because of:
- a. complexity of request
- b. first-of-a-kind nature of request
- c. NRC change in regulatory significance or focus
- d. NRC questions on previously used methodology or guidance
- e. licensee change to previously used methodology
- f. licensee reduction in current safety margin 2.
The review can not be completed without additional explanation or clarification of:
- a. input variables or analytical assumptions
- b. methodology used or results obtained
- c. applicability or bounding nature of third party analyses or data correlations
- e. no significant hazards consideration discussion
- f. environmental considerations discussion
- g. applicable regulatory requirements discussion
- h. information that appears to be incorrect and needs to be corrected
- i. response to previous RAI appears inadequate 3.
Reviewer requesting information even though the question is, or the question asks for:
- a. not directly related to the request
- c. information accessible from readily available sources and was explicitly referenced
- d. information does not appear needed given the precedent cases discussed in the request
- e. information that is not safety significant or pertinent to the regulatory finding
- f. information that is known to engineers who work in the general technical area
- g. going beyond the current licensing basis and doesnt need to be asked
- h. a formal commitment 4.
Other (please specify)
Davis-Besse Nuclear Power Station, Unit 1 cc:
Manager - Regulatory Affairs FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State - Route 2 Oak Harbor, OH 43449-9760 Director, Ohio Department of Commerce Division of Industrial Compliance Bureau of Operations & Maintenance 6606 Tussing Road P.O. Box 4009 Reynoldsburg, OH 43068-9009 Regional Administrator U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60523-4351 Resident Inspector U.S. Nuclear Regulatory Commission 5503 North State Route 2 Oak Harbor, OH 43449-9760 Barry Allen, Plant Manager FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station 5501 North State - Route 2 Oak Harbor, OH 43449-9760 Dennis Clum Radiological Assistance Section Supervisor Bureau of Radiation Protection Ohio Department of Health P.O. Box 118 Columbus, OH 43266-0118 Carol OClaire, Chief, Radiological Branch Ohio Emergency Management Agency 2855 West Dublin Granville Road Columbus, OH 43235-2206 Zack A. Clayton DERR Ohio Environmental Protection Agency P.O. Box 1049 Columbus, OH 43266-0149 State of Ohio Public Utilities Commission 180 East Broad Street Columbus, OH 43266-0573 Attorney General Office of Attorney General 30 East Broad Street Columbus, OH 43216 President, Board of County Commissioners of Ottawa County Port Clinton, OH 43252 President, Board of County Commissioners of Lucas County One Government Center, Suite 800 Toledo, OH 43604-6506 The Honorable Dennis J. Kucinich United States House of Representatives Washington, D.C. 20515 The Honorable Dennis J. Kucinich United States House of Representatives 14400 Detroit Avenue Lakewood, OH 44107 Gary R. Leidich President and Chief Nuclear Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-19 76 South Main Street Akron, OH 44308 Joseph J. Hagan Senior Vice President of Operations and Chief Operating Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 David W. Jenkins, Attorney FirstEnergy Corporation Mail Stop A-GO-18 76 South Main Street Akron, OH 44308
Davis-Besse Nuclear Power Station, Unit 1 cc:
Danny L. Pace Senior Vice President, Fleet Engineering FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 Manager, Fleet Licensing FirstEnergy Nuclear Operating Company Mail Stop A-GHE-107 395 Ghent Road Akron, OH 44333 Manager, Site Regulatory Compliance FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station Mail Stop A-DB-3065 5501 North State Route 2 Oak Harbor, OH 43449-9760 Jeannie M. Rinckel Vice President, Fleet Oversight FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308