ML021200044
| ML021200044 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 05/08/2002 |
| From: | Lyon C NRC/NRR/DLPM/LPD3 |
| To: | Skolds J Exelon Generation Co |
| References | |
| GL-96-006, TAC M96856, TAC M96857 | |
| Download: ML021200044 (4) | |
Text
May 8, 2002 Mr. John L. Skolds, President Exelon Nuclear Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 - COMPLETION OF LICENSING ACTION FOR GENERIC LETTER (GL) 96-06, ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS (TAC NOS. M96856 AND M96857)
Dear Mr. Skolds:
The Nuclear Regulatory Commission (NRC) staff issued GL 96-06 on September 30, 1996, to all holders of operating licenses for nuclear power reactors, except for those licenses that have been amended to possession-only status. GL 96-06 requested information from licensees related to two concerns: (1) water hammer and two-phase flow in the cooling water systems that serve the containment air coolers and (2) thermally-induced overpressurization of isolated water-filled piping sections in containment. On November 13, 1997, the staff issued Supplement 1 to GL 96-06 informing licensees about ongoing efforts and new developments associated with GL 96-06 and providing additional guidance for completing corrective actions.
Commonwealth Edison Company (ComEd, the former licensee) responded in letters dated October 28, 1996, January 28, May 2, and May 16, 1997, August 31 and October 30, 1998, and May 17, 1999. Subsequently, ComEd was merged into Exelon Generation Company, LLC (Exelon, the current licensee). By letter dated February 7, 2001, Exelon informed the NRC that it assumed responsibility for all pending NRC actions that were requested by ComEd. The results of the NRC staffs review of your responses to GL 96-06 follow.
Water Hammer and Two-Phase Flow You provided your assessment of this concern in letters dated January 28 and May 2, 1997, and August 31, 1998. The drywell coolers at Quad Cities are non-safety-related and are cooled by the reactor building component cooling water (RBCCW) system. The NRC staff understands that the RBCCW expansion tank provides enough static pressure to keep the cooling water from boiling as long as the water temperature does not exceed 265 EF, which will prevent the occurrence of water hammer and two-phase flow during most situations. In a follow-up telephone conversation on February 1, 1999, your staff indicated that as an additional measure to resolve the NRC staffs concerns, RBCCW operating procedures would be revised to instruct operators not to restore RBCCW flow to the drywell following a loss-of-coolant accident if the drywell temperature has been greater than 260 EF during the accident. The NRC staff is satisfied with your actions and considers the water hammer and two-phase flow elements of GL 96-06 to be closed.
Thermally-Induced Overpressurization
J. Skolds In your submittal of January 28, 1997, you identified five penetrations on each unit as potentially vulnerable to a water solid volume that may be subjected to an increase in pressure due to heating of trapped fluid. In your submittal of May 2, 1997, you identified three additional penetrations on each unit which were potentially vulnerable to thermally-induced pressurization.
In these submittals, you stated that these penetrations were operable, but that additional corrective actions would be necessary. In your submittals of May 16, 1997, August 31 and October 30, 1998, and May 17, 1999, you provided the final resolution for these eight penetrations on each unit. For Unit 1, you provided the following information: for five penetrations, relief valves have been installed to relieve excessive pressure; for one penetration, the piping will be procedurally drained prior to each startup following each refueling outage or following any outage during which the piping has been valved into service; and for two penetrations, you performed detailed piping analyses which demonstrate that the maximum thermally-induced pressures in these piping segments meet the Appendix F acceptance criteria of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code),Section III, for the Level D condition. For Unit 2, you provided the following information:
for five penetrations, relief valves have been installed to relieve excessive pressure; for one penetration, it was determined that an existing relief valve provided pressure relief; for one penetration, the piping will be procedurally drained prior to startup following each refueling outage or following any outage during which the piping has been valved into service; and for one penetration, you performed a detailed piping analysis which demonstrates that the maximum thermally-induced pressure in this piping segment meets the Appendix F acceptance criteria of the ASME Code for the Level D condition. The NRC staff concludes that your evaluations and corrective actions are reasonable and provide an acceptable resolution for the GL 96-06 issue of thermally-induced pressurization of piping runs penetrating the containment.
Finally, the staff concludes that all requested information has been provided; therefore, it considers GL 96-06 to be closed for Quad Cities Nuclear Power Station, Units 1 and 2.
Sincerely,
/RA/
Carl F. Lyon, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-254 and 50-265 cc: See next page
J. Skolds Thermally-Induced Overpressurization In your submittal of January 28, 1997, you identified five penetrations on each unit as potentially vulnerable to a water solid volume that may be subjected to an increase in pressure due to heating of trapped fluid. In your submittal of May 2, 1997, you identified three additional penetrations on each unit which were potentially vulnerable to thermally-induced pressurization.
In these submittals, you stated that these penetrations were operable, but that additional corrective actions would be necessary. In your submittals of May 16, 1997, August 31 and October 30, 1998, and May 17, 1999, you provided the final resolution for these eight penetrations on each unit. For Unit 1, you provided the following information: for five penetrations, relief valves have been installed to relieve excessive pressure; for one penetration, the piping will be procedurally drained prior to each startup following each refueling outage or following any outage during which the piping has been valved into service; and for two penetrations, you performed detailed piping analyses which demonstrate that the maximum thermally-induced pressures in these piping segments meet the Appendix F acceptance criteria of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code),Section III, for the Level D condition. For Unit 2, you provided the following information:
for five penetrations, relief valves have been installed to relieve excessive pressure; for one penetration, it was determined that an existing relief valve provided pressure relief; for one penetration, the piping will be procedurally drained prior to startup following each refueling outage or following any outage during which the piping has been valved into service; and for one penetration, you performed a detailed piping analysis which demonstrates that the maximum thermally-induced pressure in this piping segment meets the Appendix F acceptance criteria of the ASME Code for the Level D condition. The NRC staff concludes that your evaluations and corrective actions are reasonable and provide an acceptable resolution for the GL 96-06 issue of thermally-induced pressurization of piping runs penetrating the containment.
Finally, the staff concludes that all requested information has been provided; therefore, it considers GL 96-06 to be closed for Quad Cities Nuclear Power Station, Units 1 and 2.
Sincerely,
/RA/
Carl F. Lyon, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-254 and 50-265 cc: See next page DISTRIBUTION:
PUBLIC OGC KManoly PD3-2 r/f ACRS JHannon FLyon JTatum BWetzel AMendiola GHammer CRosenberg MRing, RIII ADAMS ACCESS NO. ML021200044
- No significant changes to SE OFFICE PDIII-2/PM PDIII-2/LA SPLB/BC EMEB/SC PDIII-2/SC NAME FLyon CRosenberg by THarris LMarsh*
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AMendiola DATE 05/02/02 05/02/02 02/04/99 04/23/02 05/08/02 OFFICIAL RECORD COPY
Quad Cities Nuclear Power Station Units 1 and 2 cc:
Site Vice President - Quad Cities Nuclear Power Station Exelon Generation Company, LLC 22710 206th Avenue N.
Cordova, IL 61242-9740 Quad Cities Nuclear Power Station Plant Manager Exelon Generation Company, LLC 22710 206th Avenue N.
Cordova, IL 61242-9740 Regulatory Assurance Manager - Quad Cities Exelon Generation Company, LLC 22710 206th Avenue N.
Cordova, IL 61242-9740 Quad Cities Resident Inspectors Office U.S. Nuclear Regulatory Commission 22712 206th Avenue N.
Cordova, IL 61242 William D. Leech Manager - Nuclear MidAmerican Energy Company P.O. Box 657 Des Moines, IA 50303 Vice President - Law and Regulatory Affairs MidAmerican Energy Company One River Center Place 106 E. Second Street P.O. Box 4350 Davenport, IA 52808 Chairman Rock Island County Board of Supervisors 1504 3rd Avenue Rock Island County Office Bldg.
Rock Island, IL 61201 Regional Administrator U.S. NRC, Region III 801 Warrenville Road Lisle, IL 60532-4351 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, IL 62704 Document Control Desk-Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President - Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President Mid-West Operations Support Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Director - Licensing Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
Quad Cities Nuclear Power Station Units 1 and 2 Senior Counsel, Nuclear Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Dresden and Quad Cities Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555