ML20216F327
| ML20216F327 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 04/13/1998 |
| From: | John Hickman NRC (Affiliation Not Assigned) |
| To: | Kingsley O COMMONWEALTH EDISON CO. |
| References | |
| GL-96-06, GL-96-6, TAC-M96782, TAC-M96783, TAC-M96789, TAC-M96790, NUDOCS 9804170031 | |
| Download: ML20216F327 (6) | |
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April 13,1998 Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GENERIC LETTER (GL) 96-06 RESPONSE FOR BRAIDWOOD STATION, UNITS 1 AND 2, AND BYRON STATION, UNITS 1 AND 2 (TAC NOS. M96782, M96783, M96789 AND M96790)
Dear Mr. Kingsley:
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 assure that they are not vulnerable to waterhammer and two-phase flow conditions. Commonwealth Edison Company (Comed), provided its assessment for Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, in letters dated January 28,1997, and May 2,1997. In order to complete our review of Comed's resolution of the waterhammer and two-phase flow issues, we will require additional information as discussed in the enclosure. Please provide this information by June 30, 1998, in order to support our review schedule.
Should you have any questions on this issue, please contact me at (301) 415-3017.
Sincerely, ORIG. SIGNED BY:
John B. Hickman, Project Manager Project Directorate ill-2
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Division of Reactor Projects - Ill/IV Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455 STN 50-456, STN 50-457
Enclosure:
As stated I
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WASHINGTON, D.C. 20066 4 001 49***,*,o April 13, 1998 Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West lli 1400 Opus Place, Suite 500 Downers Grove, IL 60515
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GENERIC LETTER (GL) 96-06 RESPONSE FOR BRAIDWOOD STATION, UNITS 1 AND 2, AND BYRON STATION, UNITS 1 AND 2 (TAC NOS. M96782, M96783, M96789 AND M96790)
Dear Mr. Kingsley:
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 assure that they are not vulnerable to waterhammer and two-phase flow conditions. Commonwealth Edison Company (Comed), provided its assessment for Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, in letters dated January 28,1997, and May 2,1997, in order to complete our review of Comed's resolution of the waterhammer and two-phase flow issues, we will require additionalinformation as discussed in the enclosure. Please provide this information by June 30, 1998, in order to support our review schedule.
Should you have any questions on this issue, please contact me at (301) 415-3017.
Sincerely,
' John B. Hickman, Project Manager Project Directorate 111-2 Division of Reactor Projects -lil/lV Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455 STN 50-456, STN 50-457
Enclosure:
As stated cc w/ encl: See next page i
O. Kingsley Byron /Braidwood Stations Commonwealth Edison Company i
cc:
Ms. C. Sue Hauser, Project Manager George L. Edgar Westinghouse Electric Corporation Morgan, Lewis and Bochius Energy Systems Business Unit 1800 M Street, N.W.
Post Office Box 355 Washington, DC 20036 Pittsburgh, Pennsylvania 15230 Attomey General Joseph Gallo 500 S. Second Street Gallo & Ross Springfield, Illinois 62701 1250 Eye St., N.W., Suite 302 Washington, DC 20005 Illinois Department of Nuclear Safety I
Office of Nuclear Facility Safety Michael 1. Miller, Esquire 1035 Outer Park Drive Sidley and Austin Springfield, Illinois 62704 One First National Plaza Chicago, Illinois 60603 Commonwealth Edison Company Byron Station Manager Howard A. Leamer 4450 N. German Church Road Environmentallaw and Policy Byron, Illinois 61010-9794 Centerof the Midwest 203 N. LaSalle St. Suite 1390 Commonwealth Edison Company Chicago, Illinois 60601 Site Vice President - Byron 4450 N. German Church Road U.S. Nuclear Regulatory Commission Byron, Illinois 61010-9794 Byron Resident inspectors Office 4448 N. German Church Road U.S. Nuclear Regulatory Commission Byron, Illinois 61010-9750 Braidwood Resident inspectors Office RR 1, Box 79 Regional Administrator, Region Ill' Braceville, Illinois 60407 U.S. Nuclear Regulatory Commission 801 Warrenville Road Mr. Ron Stephens Lisle, Illinois 60532-4351 tilinois Emergency Services and Disaster Agency Ms. Lorraine Creek 110 E. Adams Street RR 1, Box 182 Springfield, Illinois 62706 Manteno, Illinois 60950 Chairman Chairman, Ogle County Board Will County Board of Supervisors Post Office Box 357 Will County Board Courthouse 1
Oregon, Illinois 61061 Joliet, Illinois 60434 Mrs. Phillip B. Johnson Commonwealth Edison Company 1907 Stratford Lane Braidwood Station Manager i
Rockford, Illinois 61107 RR 1, Box 84
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Braceville, Illinois 60407 4
O. Kingsley Commonwealth Edison Company Byron /Braidwood Stations Ms. Bridget Little Rorem Ms. Irene Johnson, Licensing Director Appleseed Coordinator Nuclear Regulatory Services 117 N. Linden Street Commonwealth Edison Company Essex, Illinois 60935 Executive Towers West lll 1400 Opus Place Suite 500 Document Control Desk-Licensing Downers Grove,IL 60515 Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Commonwealth Edison Company Reg. Assurance Supervisor-Braidwood RR 1, Box 79 Commonwealth Edison Company Braceville, Illinois 60407 Site Vice President - Braidwood RR 1, Box 84 Braceville,IL 60407 Commonwealth Edison Company Reg. Assurance Supervisor-Byron 4450 N. German Church Road Mr. David Helwig Byron, Illinois 61010-9794 Senior Vice President Commonwealth Edison Company Mr. Michael J. Wallace Executive Towers West lli Senior Vice President 1400 Opus Place, Suite 900 Downers Grove, IL 60515 Commonwealth Edison Company Executive Towers West 111 1400 Opus Place, Suite 900 Mr. Gene H. Stanley Downers Grove,IL 60515 PWR's Vice President Commonwealth Edison Company Executive Towers West lli 1400 Opus Place, Suite 900 Downers Grove,IL 60515 Mr. Steve Peny BWR's Vice President Commonwealth Edison Company Executive Towers West ll1 1400 Opus Place, Suite 900 Downers Grove, IL 60515 Mr. Dennis Farrar Regulatory Services Manager Commonwealth Edison Company Executive Towers West lil 1400 Opus Place, Suite 500 Downers Grove, IL 60515
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REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GENERIC LETTER 96-06 ISSUES AT BRAIDWOOD AND BYRON 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 assure that they are not vulrberable to waterhammer and two-phase flow conditions. Commonwealth Edison Company (Comed) provided its assessment for Braidwood, Units 1 and 2, and Byron, Units 1 and 2, in letters dated January 28,1997, and May 2,1997. Comed's response indicated that the effects of waterhammer and two-phase flow were analyzed for a representative piping configuration. In order to adequately assess Comed's resolution of the waterhammer and two-phase flow issues, the following additional information is requested:
- 1. If a methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-i induced Waterhammer," was used in evaluating the effects of waterhammer, describe this a!temate methodology in detail. Also, explain why this methodology is applicable and gives conservative results for both the Braidwood and Byron units (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 involved (see Standard Review Plan Section 3.9.1). Supplement the information contained in the May 2,1997, submittal as necessary,
- 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 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).
Information that is contained in the May 2,1997, submittal that requires no further explanation need not be repeated.
- c. Provide a detailed description of the " worst case" scenarios for waterhammer 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. Additional examples include:
. the effects of void fraction on flow balance and heat transfer; j
the consequences of steam formation, transport, and accumulation; e
cavitation, resonance, and fatigue effects; and erosion considerations.
Comed may find NUREG/CR-6031, " Cavitation Guide for Control Valves," helpful in addressing some aspects of the two-phase flow analyses.
ENCLOSURE
.c 2-
- d. Confirm that the analyses included a complete failure mode and effects analysis (FMEA) i 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."
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- 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 for the Braidwood and Byron units.
- 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, i
relative elevations, lengths of piping runs, and the location of any orifices and flow restrictions.
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