ML20195K060
| ML20195K060 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/15/1999 |
| From: | Eaton R NRC (Affiliation Not Assigned) |
| To: | Necci R NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| GL-88-20, TAC-M83642, NUDOCS 9906210195 | |
| Download: ML20195K060 (6) | |
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Mr. R. P. Necci - Vice President June 15,1999 1
Nuclear Oversight and Regulatory Affairs I
c/o Mr. David A. Smith Northeast Nuclear Energy Company
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P. O. Box 128 Waterford, CT 06385
SUBJECT:
MILLSTONE NUCLEAR POWER STATION, UNIT NO 2, INDIVIDUAL PLANT' EXAMINATION OF EXTERNAL EVENTS (IPEEE) SUPPLEMENTAL REQUEST.
l OF ADDITIONAL INFORMATION i
(TAC NO. M83642) j 3
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Dear Mr. Necci:
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Based on your response to our February 24,1998, request for additional information, the staff
' was unable to conclude that you have met the intent of Supplement 4 to Generic Letter 88-20.
Therefore, the staff developed the enclosed questions regarding the fire-related IPEEE analyses.
j These questions were discussed with Mr. Joshi of your staff as well as the expected response l
' date of 60 days from receipt of the new guidance from EPRI regarding heat release rates.
I If you have any questions regarding this letter, please call me on (301) 415-3041.
Sincerely, ORIGINAL SIGNED BY:
Ronald B. Eaton, Senior Project Manager, Section 2 l
Project Directorate i Division of Licensing Project Management I
i Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
As stated cc w/ encl: See next page DISTRIBUTION:
Docket File PUBLIC PD#1-2 Reading S. Black OGC ACRS R. Hernan J. Durr, RI pOOq Q R. Eaton A. Rubin DOCUMENT NAME: G:\\PDI-2\\ Millstone 2\\l P EE ERAl.W P D To recelve a copy of this document, indicate c" in the box OFFICE PD)MM PDI-2/LA 6 PDI-2/pC Lilo'n;db.jJClark84 JCkord NAME RE DATE l)/b /99 8 4 / /6 /99 h db /99 OFFICIAL RECORD COPY 9906210195 990615
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PDR ADOCK 05000336 F
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3 UNITED STATES g
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NUCLEAR REGULATORY COMMISSION j
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WASHINGTON, D.C. 20656-0001
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June 15,199.9.
Mr. R.' P. Necci - Vice _ President Nuclear Oversight and Regu!atory Affairs
. c/o Mr. David A. Smith
. Northeast Nuclear Energy Company P. O. Box 128 Waterford, CT 06385
SUBJECT:
MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2, INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE) SUPPLEMENTAL REQUEST OF ADDITIONAL INFORMATION (TAC NO. M83642)
Dear Mr. Necci:
w Based on your response to our February 24,1998, request for additional information, the staff was unable to conclude that you have met the intent of Supplement 4 to Generic Letter 88-20.
Therefore, the staff developed the encicsed questions regarding the fire-related IPEEE-
- analyses.
These questions were discussed with Mr. Joshi of your staff as weX as the expected response date of 60 days from receipt of the new guidance from EPRI regarding heat release rates.
If you have any questions regarding this letter, please call me on (301) 415-3041.
Sincerely, fl Y onald B. Eaton, Senior Project Manager, Section 2 i
Project Directorate 1 -
Division of Licensing Project Management i
Office of Nuclear Reactor Regulation i
Docket No. 50-336 i
Enclosure:
As stated cc w/ encl: See next page i
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' Millstona Nucitar Powsr Station
.. Unit 2 cc:
.Ms. L M. Cuoco Ernest C. Hadley, Esquire Senior Nuclear Counsel 1040 B Main Street Northeast Utilities Service Company P.O. Box 549 '
. P. O. Box 270 West Wareham, MA 02576
- Hartford, CT 06141-0270 Mr. R. P. Necci Edward L. Wilds', 'Jr., Ph.D.
Vice President - Nuclear Oversight Director, Division of Radiation and Regulatory Affairs Department of Environmental Protection Northeast Nuclear Energy Company 79 Elm Street.
P. O. Box 128 -
Hartford, CT 06106-5127 -
Waterford, CT 06385 Regional Administrator, Region i Mr. J..T. Carlin U.S. Nuclear Regulatory Commission Vice President - Human Services 475 Allendale Road Northeast Utilities Service Company King of Prussia, PA 19406 P. O. Box 128 Waterford, CT 06385 First Selectmen Town of Waterford Mr. Allan Johanson, Assistant Director
.15 Rope Ferry Road.
Office of Policy and Management
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Waterford, CT 06385 Policy Development and Planning Division Mr. Wayne D. Lanning, Director 450 Capitol Avenue - MS# 52ERN
. Millstone inspections P. O. Box 341441 Office of the Regional Administrator Hartford. CT 06134-1441 475 Allendale Road.
King of Prussia, Pt. 19406-1415 Mr. M. H. ; Brothers Vice President - Millstone Operations Charles Brinkman, Manager Northeast Nuclear Energy Company Washington Nuclear Operations P.O. Box 128 ABB Combustion Engineering Waterford, CT 06385 12300 Twinbrook Pkwy, Suite 330 Rockville, MD 20852 Mr. J. A. Price Director-Unit 2 Operations Senior Resident inspector Northeast Nuclear Energy Company Millstone Nuclear Power Station P.O. Box 128 c/o U.S. Nuclear Regulatory Commission Waterford, CT 06385 P.O. Box 513 Niantic, CT 06357 Mr. L. Olivier -
Senior Vice President and Chief Mr. F. C. Rothen _
Nuclear Officer - Millstone Vice President - Nuclear Work Services Northeast Nuclear Energy Company Northeast Utilities Service Company P.O. Box 128 P. O. Box 12P.
Waterford, CT 06385 -
Waterford, CT 06385
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Millstone Nuclear Power Station Unit 2 cc:
i Citizens Regulatory Commission ATTN: Ms. Susan Perry Luxton Ms. Nancy Burton 180 Great Neck Road 147 Cross Highway Waterford, CT 06385 Redding Ridge, CT 00870 Deborah Katz, President Citizens Awareness Network P. O. Box 83 Shelburne Falls, MA 03170 Ms. Terry Concannon Co-Chair Nuclear Energy Advisory Council Room 4100 Legislative Office Building Capitol Avenue Hartford, CT 06106 Mr. Evan W. Woollacott Co-Chair Nuclear Energy Advisory Council 128 Terry's Plain Road Simsbury, CT 06070 Little Harbor Consultants, Inc.
Millstone -ITPOP Project Office P. O. Box 0630 Niantic, CT 06357-0630 Attorriey Nicholas J. Scobbo, Jr.
Ferriter, Scobbo, Caruso, Rodophele, PC 75 State Street, 7th Floor Boston,'MA 02109 i
Mr. D. B. Amerine
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Vice President - Engineering Services Northeast Nuclear Energy Company P. O. Box 128 Waterford, CT 06385 Mr. D. A. Smith Manager-Regulatory Affairs Northeast Nuclear Energy Company P. O. Box 128 Waterford, CT 06385
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l MILLSTONE NUCLEAR POWER STATION UNIT 2 Reauest For Additional Informatio.n on IPEEE Submittal 1.
The first fire-related item in the U. S. Nuclear Regulatory Commission's (USNRC) request for additional information (RAl) dated February 24,1998, questioned the heat release rate (HRR) for electrical panels assumed in the licensee's submittal and requested that the licensee consider the impact of higher HRR values on the risk analysis. The Millstone response of December 1998 expanded on the basis for the assumed HRR values citing again the Electric Power Research Institute (EPRI) Fire FRA [probablistic risk assessment]
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/mplementefion Guice as the primary basis. However, no assessment of the impact of higher HRR values was provided. The USNRC has raised this exact same concern in a
" generic' context with EPRi. New guidance from EPRI is anticipated.
l in particular, the cited nominal HRR value of 65 BTUs, from which Millstone extracted its assumed 63 BTUs value, was based on Sandia National Laboratories' fire tests where the test panels only contained qualified (per IEEE-383) cables, and where the fire did not spread beyond a single bundle of cables. In tests where the fire spread beyond a single cable bundle, much higher HRR values were observed. Hence, the 65 BTU /s HRR assumption should only be applied to electrical panels where it can be reasonably assumed that the fire will remain confined to a single bundle of qualified cables. In some cases, the fuelload of a panel may indeed be confined to a single bundle of qualified cables, or to two bundles' located on opposite sides of the panel. Under these circumstances, the assumed 65 BTU /s HRR may be reasonable. However, in many panels the fuelload will be distributed. This assessment must include all potential ignitable materials (e.g., cables, circuit cards, transformers, motors, routing " wire-ways," and instrument housings). Under conditions of a distributed fuelload, fire-spread beyond a single cable bundle should be postulated and a higher HRR value should be assumed.
4 When available, please review the revised guidance being prepared by EPRI relating to this aspect of the Fire FRA /mplementation Guide. Given the revised guidance, please reconsider your response to the original RAl. The licensee should identify cases where the original assumption of 65 BTU /s nominal panel HRR is inconsistent with the revised guidance and assess the impact of higher HRR values on the estimated fire-induced core damage frequencies for these scenarios.
2.
In the USNRC RAI of February 24,1998, fire-related RAI item 6 requested that licensee provide an assessment of its alternate shutdown procedures including specific consideration of the plant's sell-induced station black-out procedures. The licensee's response of December 1998 provided some of the requested information, but did not fully answer the question. The following specific points of concem were identified:
The licencee provided a discussion of the actions that must be taken to achieve safe shutdown, but did not provide the requested analysis of the human error probabilities (HEPs) associated with these required actions. Numerous actions are required in the control room once an evacuation is declared, control must then be transferred to the fire shutdown panel (FSP), establish the unit cross-tie, and control the reactor from the FSP. No conditional probability for failure to complete the required actions was provided.
ENCLOSURE
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The licensee stated that 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> are available to complete the Unit 1 cross-tie. This assessment does not consider circuit failures caused by the fire that could result in lifting of the power-operated relief valves, and the consequences if such faults are not i
mitigated very quickly.
No assessment of potential control circuit damage prior to isolation of the main control room was provided.
The conditional probability of control room abandonment given a fire (1.0E-3) is optimistic in comparison to generalindustry practice. It would appear that the licensee has allowed an overly optimistic credit for detection and suppression. Even the EPRI interpretations of the SNL tests involving in-cabinet fire detectors resulted in a conditional abandonment probability of 3.4E-3 (from the Fire FRA implementation Guide).
Please review your response to the previous RAI and provide a revised response that includes an assessment of the risk contribution of control room abandonment scenarios.
In the response, please address each of the four preceding points of concerns.
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