ML20217Q646
| ML20217Q646 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/05/1998 |
| From: | Mcdonald D NRC (Affiliation Not Assigned) |
| To: | Bowling M NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| GL-96-06, GL-96-6, TAC-M96833, NUDOCS 9805080264 | |
| Download: ML20217Q646 (7) | |
Text
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a lMay 5, 1998
- q r-Mr. Martin L. Bowling, Jr.
' Recovery Officer-Millstone Unit 2 Northeast Nuclear Energy Company c/o,'.is. Patricia A. Loftus Director-Regulatory Affairs P.O. Box 128 Waterford, CT 06385
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING RESOLUTION OF GENERIC LETTER (GL) 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY l
AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS," DATED SEPTEMBER 30,1996, MILLSTONE, UNIT NO. 2 (TAC NO. M96833) 1
Dear Mr. Bowling:
By letter dated January 28,1997, Northeast Nuclear Energy Company (NNECO) responded to GL 96-06 providing,its assessment of the waterhamnier and two-phase flow issues for Millstone, Unit 2.
The NRC staff has completed a preliminary review of your request and has identified several issues that require additionalinformhtion. Please respond to the enclosed request for additionalinformation (RAI) in order for the staff to complete its review. We request that the response to the RAI be provided at least 30 days prior to entering Mode 4.
Sincerely, Original signed by:
Daniel G. Mcdonald Jr., Serior Project Manager Special Projects Office - Licensing Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
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Mr. Martin L. Bowling, Jr.
Recovery Officer-Millstone Unit 2
~ Northeast Nuclear Energy Company c/o Ms. Patricia A. Loftus Director-Regulatory Affairs P.O. Box 128 -
Waterford, CT 06385
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING RESOLUTION OF GENERIC LETTER (GL) 96-06, " ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS," DATED SEPTEMBER 30,1996, MILLSTONE, UNIT NO. 2 (TAC NO. M96833)
Dear Mr. Bowling:
By letter dated January 28,1997, Northeast Nuclear Energy Company (NNECO) responded to GL 96-06 providing its assessment of the waterhammer and two-phase flow issues for Millstone, Unit 2.
The NRC staff has completed a preliminary review of your request and has identified several issues that require additionalinformation. Please respond to the enclosed request for additional information (RAI) in order for the staff to complete its review. We request that the response to the RAI be provided at least 30 days prior to entering Mode 4.
Sincerely, h_t b
Daniel G. Mcdonald Jr., Senior Project M nager Special Projects Office - Licensing Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
As stated cc w/ encl: See next page l
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REQUEST FOR ADDITIONAL INFORMATION l
MILLSTONE NUCI FAR POWER STATION. UNIT 2 DOCKET NO. 338 TAC M96833 Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request for licensees to evaluate cooling water systems that serve containment air coolers to assura that they are not vulnerable to waterhammer and two-phase flow conditions. Northeast Nuclear Energy Company (the licensee) provided its assessment of the waterhammer and two-phase flow issues for Millstone Unit 2 in a letter dated January 28,1997. '
At Millstone 2, the Reactor Building Closed Cooling Water (RBCCW) system (a closed loop I
cooling water system with a vented surge tank) supplies cooling water to the Containment Air l
Recirculation (CAR) Coolers as well as to other equipment. The licensee provided information about the analyses that were performed to address the waterhammer and two-phase flow issues, and indicated that the limiting case for Millstone 2 may be the loss-of-coolant accident (LOCA) with a loss of offsite power (LOOP), and failure of an RBCCW pump to start, in this case, when flow is manually restored to the affected header sometime later during the course of the event, a relatively severe waterhammer (as compared to other scenarios) could occur. The j
licensee indicated that the analyses would be finalized and corrective actions taken prior to unit startup. In order to assess the licensee's resolution of these issues, the following additional information is requested:
1.
If a methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-Induced Waterhammer," was used in evaluating the effects of waterhammer, describe this attemate methodology in detail. Also, explain why this methodology is applicable and gives conservative results (typically accomplished through rigorous plant-specific modeling, testing, and analysis).
2.
For both the waterhammer and two-phase flow analyses, provide the following information:
a.
Identify any computer codes that were used in the waterhammer and two-phase flow analyses and describe the methods used to benchmark the codes for the specific loading conditions insolved (see Standard Review Plan Section 3.9.1).
b.
Describe and justify all assumptions and input parameters (including those used in any computer codes) such as amplifications due to fluid structure interaction, cushioning, speed of sound, force reductions, and mesh sizes, and explain why
' It is acceptable to supplement the information that was provided in the January 28 response with additional 4
information as necessary to proi ide a complete response.
The assumption that service water temperature is at the maximum value may not be conservative for reinitiation of now following the LOCA/ LOOP event because a larger tomi sture difference (e.g., lower service water temperature) would result in a more rapid bubble collapse.
Enclosure
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2-the values selected give conservative results. Also, provide justification for omitting any effects that may be relevant to the analysis (e.g., fluid structure interaction, flow induced vibration, erosion).
c.
' Provide a detailed description of the " worst case
- scenarios for waterhammer i
and two-phase flow, taking into consideration the complete range of event possibilities, system configurations, and parameters. For example, all waterhammer types and water slug scenarios should be considered, as well as temperatures, pressures, flow rates, load combinations, and potential component failures. Additionalexamplesinclude:
3 the effects of void fraction on flow balance and heat transfer;-
)
the consequences of steam formation, transport, and accumulation;
=
-1 cavitation, resonance, and fatigue effects; and I
erosion considerations.
Licensees may find NUREG/CR-6031, " Cavitation Guide for Control Valves,"
helpfulin addressing some aspects of the two-phase flow analyses. (Note: it is important for licensees to realize that in addition to heat transfer considerations, two-phase flow also involves structural and system integrity concems that must be addressed).
d.
Confirm that the analyses included a complete failure modes and affects analysis (FMEA) for all components (including electrical and pneumatic failures) that could impact performance of the cooling water system and confirm that the FMEA is documented and available for review, or explain why a complete and fully documented FMEA was not performed.
e.
Explain and justify all uses of " engineering judgement."
4 3.
Determine the uncertainty in the waterhammer and two-phase flow analyses, explain how the uncertainty was determined, and how it was accounted for in the analyses to assure conservative results.
4.
Confirm that the waterhammer and two-phase flow loading conditions do not exceed any design specifications or recommended service conditions for the piping system and components, including those stated by equipment vendors; and confirm that the system will continue to perform its design-basis functions as assumed in the safety analysis report for the facility.
5.
Provide a simplified diagram of the system, showing major components, active components, relative elevations, lengths of piping runs, and the location of any orifices and flow restrictions.
O f
O 6.
Since reliance is being placed on RBCCW surge tank level in addressing the waterhammer and two-phase flow concerns, describe how the minimum surge tank level requirements vil be assured, including justification for reliance on any nonsafety grade instrumentation and annunciation in this regard, and explain why it would not be appropriate to establish Technical Specification requirements for maintaining surge tank hvel.
7.
Dwcribe in detail any plant modifications or procedural changes that have been made or are planned to be made to resolve the waterhammer and two-phase flow issues.-
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Northeast Nuclear Energy Company Millstone Nuclear Power Station Unit 2 l
cc:
Lillian M. Cuoco, Esquire Mr. F. C. Rothen Senior Nuclear Counsel Vice President - Work Services Northeast Utilities Service Company Northeast Utilities Service Company P. O. Box 270 P. O. Box 128 l
. Hartford, CT 06141-0270 Waterford, CT 06385 l
Mr. John Buckingham Ernest C. Hadley, Esquire Department of Public Utility Control '
1040 B Main Street Electric Unit P.O. Box 549 10 Liberty Square West Wareham, MA 02576 New Britain, CT 06051
)
i Mr. John Streeter Mr. Kevin T. A. McCarthy, Director Vice President - Nuclear Oversight Monitoring and Radiation Division Northeast Utilities Service Company Department of Environmental Protection P. O. Box 128 79 Elm Street Waterford, CT 06385 Hartford, CT 06106-5127 Mr. David Amerine Regional Administrator, Region i Vice President - Nuclear Engineering U.S. Nuclear Regulatory Commission and Support 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 Hall of Records Office of Policy and Management 200 Boston Post Road Policy Development and Planning I
Waterford, CT 06385 Division j
450 Capitol Avenue - MS# 52ERN Mr. Wayne D. Lanning P. O. Box 341441 Deputy Director of Inspections Hartford, CT 06134-1441 Special Projects Office 475 Allendale Road Mr. M. H. Brothers King of Prussia, PA 19406-1415 Vice President - Operations Northeast Nuclear Energy Company Charles Brinkman, Manager P.O. Box 128 -
Washington Nuclear Operations Waterford, CT 06385 ABB Combustion En ineering w
12300 Twinbrook Pkwy, Suite 330 Mr. J. A. Price Rockville, MD 20852 Unit Director-Millstone Unit 2 Northeast Nuclear Energy Company Senior Resident inspector P.O. Box 128 Millstone Nuclear Power Station Waterford, CT 06385 c/o U.S. Nuclear Regulatory Comm!ssion P.O. Box 513 Niantic, CT 06357
l N:sthe:st Nuclear Energy Company Millstone Nuclear Power Station c
l Unit 2 cc:
Mr. B. D. Kenyon Attomey Nicholas J. Scobbo, Jr.
Chief Nucler Officer-Millstone Ferriter, Scobbo, Caruso, Rodophele, PC Northeast Nuclear Energy Company 1 Beacon Street,11th Floor P.O. Box 128 Boston, MA 02108 Waterford, CT 06385 Citizens Regulatory Commission ATTN: Ms. Susan Perry Luxton 180 Great Neck Road Waterford, CT 06385 j
Deborah Katz, President l
Citizens Awareness Network l
P. O. Box 83 Shelbume Falls, MA 03170 l
The Honorable Terry Concannon l
Co-Chair Nuclear Energy Advisory Council Room 4035 I
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 Mr. Daniel L. Curry l
Project Director Parsons Power Group Inc.
(
2675 Morgantown Road i
Reading, PA 19607 Mr. Don Schopfer Verification Team Manager Sargent & Lundy 55 E. Monroe Street Chicago,IL 60603 l
,