ML042240334
| ML042240334 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Peach Bottom, Oyster Creek, Byron, Braidwood, Limerick, Clinton, Quad Cities, LaSalle, Crane |
| Issue date: | 10/01/2004 |
| From: | Anthony Mendiola NRC/NRR/DLPM/LPD3 |
| To: | Crane C AmerGen Energy Co |
| Pickett , NRR/DLPM, 415-1364 | |
| References | |
| TAC MC3000, TAC MC3001, TAC MC3002, TAC MC3003, TAC MC3004, TAC MC3005, TAC MC3006, TAC MC3007, TAC MC3008, TAC MC3009, TAC MC3010, TAC MC3011, TAC MC3012, TAC MC3013, TAC MC3014, TAC MC3015, TAC MC3016 | |
| Download: ML042240334 (22) | |
Text
October 1, 2004 Mr. Christopher M. Crane, President and Chief Executive Officer AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, Illinois 60555
SUBJECT:
SAFETY EVALUATION ON RELIEF REQUEST TO USE CODE CASE N-661 AT BRAIDWOOD STATION, UNITS 1 AND 2 (TAC NOS. MC3000, MC3001); BYRON STATION, UNITS 1 AND 2 (TAC NOS. MC3002, MC3003); CLINTON POWER STATION (TAC NO. MC3004); DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 (TAC NOS. MC3005, MC3006); LASALLE COUNTY STATION, UNITS 1 AND 2 (TAC NOS. MC3007, MC3008); LIMERICK GENERATING STATION, UNITS 1 AND 2 (TAC NOS. MC3009, MC3010); OYSTER CREEK GENERATING STATION (TAC NO. MC3011); PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 (TAC NOS. MC3012, MC3013); QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 (TAC NOS. MC3014, MC3015) AND THREE MILE ISLAND, UNIT 1(TAC NO. MC3016)
Dear Mr. Crane:
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by Exelon Generation Company, LLC (Exelon, the licensee), and AmerGen Energy Company, LLC (AmerGen, the licensee), in its letter (ML041210175) dated April 26, 2004 (RS-04-065). The licensees requested that the NRC approve ASME Code Case N-661, Alternative Requirements for Wall Thickness Restoration of Class 2 and 3 Carbon Steel Piping for Raw Water Service for use at Braidwood Station, Units 1 and 2; Byron Station, Units 1 and 2; Clinton Power Station; Dresden Nuclear Power Station, Units 2 and 3; LaSalle County Station, Units 1 and 2; Limerick Generating Station, Units 1 and 2; Oyster Creek Generating Station; Peach Bottom Atomic Power Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1 and 2; and Three Mile Island, Unit 1. The request was made pursuant to Section 50.55a(a)(3)(i)of Title 10 of the Code of Federal Regulations (10 CFR).
For the reasons set forth in the enclosed Safety Evaluation, the staff concludes that the licensee has provided an acceptable alternative to the requirements of IWA-4120(a) of the 1989 Edition (or IWA-4410(a) and (b) of the 1995 Edition through 1996 Addenda) of the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code),Section XI, and IWA-4310 of 1989 Edition (or IWA-4611.1 of the 1995 Edition through 1996 Addenda) of ASME Code Section XI, subject to the following three conditions, which were proposed in the licensees application and must be met when using Code Case N-661. These conditions are: (a) if the root cause of the degradation has not been determined, the repair is only acceptable for one cycle, (b) weld overlay repair of an area can only be performed once in the same location and (c) when through-wall repairs are made by welding on surfaces that are wet or exposed to water, the weld overlay repair is only acceptable until the next refueling outage.
C. Crane The staff concludes that the proposed alternative, as supplemented by the three conditions listed above, provides reasonable assurance of structural integrity and an acceptable level of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for Braidwood Station, Units 1 and 2; Byron Station, Units 1 and 2; Clinton Power Station; Dresden Nuclear Power Station, Units 2 and 3; LaSalle County Station, Units 1 and 2; Limerick Generating Station, Units 1 and 2; Oyster Creek Generating Station; Peach Bottom Atomic Power Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1 and 2; and Three Mile Island, Unit 1, for each plant specific current 10-year inservice inspection interval, or until Code Case N-661 is approved for general use by reference in 10 CFR 50.55a.
After that time, the licensee must follow the conditions, if any, specified in the rule. All other ASME Code,Section XI, requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Sincerely,
/RA/
Anthony J. Mendiola, Chief, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos.:
STN 50-456, STN 50-457, STN 50-454, STN 50-455, 50-461, 50-237, 50-249, 50-373, 50-374, 50-352, 50-353, 50-219, 50-277, 50-278, 50-254, 50-265 and 50-289.
Enclosure:
Safety Evaluation cc w/encls: See next page
C. Crane The staff concludes that the proposed alternative, as supplemented by the three conditions listed above, provides reasonable assurance of structural integrity and an acceptable level of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for Braidwood Station, Units 1 and 2; Byron Station, Units 1 and 2; Clinton Power Station; Dresden Nuclear Power Station, Units 2 and 3; LaSalle County Station, Units 1 and 2; Limerick Generating Station, Units 1 and 2; Oyster Creek Generating Station; Peach Bottom Atomic Power Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1 and 2; and Three Mile Island, Unit 1, for each plant specific current 10-year inservice inspection interval, or until Code Case N-661 is approved for general use by reference in 10 CFR 50.55a.
After that time, the licensee must follow the conditions, if any, specified in the rule. All other ASME Code,Section XI, requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Sincerely,
/RA/
Anthony J. Mendiola, Chief, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos.:
STN 50-456, STN 50-457, STN 50-454, STN 50-455, 50-461, 50-237, 50-249, 50-373, 50-374, 50-352, 50-353, 50-219, 50-277, 50-278, 50-254, 50-265 and 50-289.
Enclosure:
Safety Evaluation cc w/encls: See next page DISTRIBUTION:
PUBLIC PDIII-2 R/F AMendiola PCoates DPickett GDick MBanerjee LRossbach RLaufer JClifford GWunder TColburn PTam TTate ACRS OGC GHill (20)
TBoyce EReichelt TChan SReynolds, RIII ADAMS Accession Number: ML042240334 OFFICE PM:PD3-2 LA:PD3-2 SC:EMCB OGC nlo w/ comments SC:PD3-2 NAME DPickett PCoates TChan*
RWeisman AMendiola DATE 09/02/04 09/02/04 07/26/04 09/14/04 10/01/04 OFFICIAL RECORD COPY
- See TChan to AMendiola memorandum dated July 26, 2004 Byron/Braidwood Stations cc:
Dwain W. Alexander, Project Manager Westinghouse Electric Corporation Energy Systems Business Unit Post Office Box 355 Pittsburgh, PA 15230 Joseph Gallo Gallo & Ross 1025 Connecticut Ave., NW, Suite 1014 Washington, DC 20036 Howard A. Learner Environmental Law and Policy Center of the Midwest 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office 4448 N. German Church Road Byron, IL 61010-9750 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107 George L. Edgar Morgan, Lewis and Bockius 1800 M Street, NW Washington, DC 20036-5869 Attorney General 500 S. Second Street Springfield, IL 62701 Illinois Emergency Management Agency Division of Disaster Assistance &
Preparedness 110 East Adams Street Springfield, IL 62701-1109 Byron Station Plant Manager Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Site Vice President - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office 35100 S. Rt. 53, Suite 79 Braceville, IL 60407 Chairman Will County Board of Supervisors Will County Board Courthouse Joliet, IL 60434 Braidwood Station Plant Manager Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Ms. Bridget Little Rorem Appleseed Coordinator 117 N. Linden Street Essex, IL 60935 Byron/Braidwood Stations Document Control Desk - Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Site Vice President - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Senior Vice President - Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President of Operations - Mid-West Pressurized Water Reactors Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Regulatory Assurance Manager - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Regulatory Assurance Manager - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Associate General Counsel 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 Manager Licensing - Braidwood, Byron and LaSalle Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Clinton Power Station, Unit 1 cc:
Vice President of Operations - Mid-West Boiling Water Reactors AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Dresden, Quad Cities, and Clinton AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, IL 60555 Regulatory Assurance Manager - Clinton AmerGen Energy Company, LLC Clinton Power Station RR3, Box 228 Clinton, IL 61727-9351 Site Vice President - Clinton Power Station AmerGen Energy Company, LLC Clinton Power Station RR 3, Box 228 Clinton, IL 61727-9351 Clinton Power Station Plant Manager AmerGen Energy Company, LLC Clinton Power Station RR 3, Box 228 Clinton, IL 61727-9351 Resident Inspector U.S. Nuclear Regulatory Commission RR #3, Box 229A Clinton, IL 61727 Chief Operating Officer AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, IL 60555 R. T. Hill Licensing Services Manager General Electric Company 175 Curtner Avenue, M/C 481 San Jose, CA 95125 Chairman of DeWitt County c/o County Clerks Office DeWitt County Courthouse Clinton, IL 61727 J. W. Blattner Project Manager Sargent & Lundy Engineers 55 East Monroe Street Chicago, IL 60603 LaSalle County Station Units 1 and 2 cc:
Site Vice President - LaSalle County Station Exelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757 LaSalle County Station Plant Manager Exelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757 Regulatory Assurance Manager - LaSalle Exelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757 U.S. Nuclear Regulatory Commission LaSalle Resident Inspectors Office 2605 North 21st Road Marseilles, IL 61341-9756 Phillip P. Steptoe, Esquire Sidley and Austin One First National Plaza Chicago, IL 60603 Assistant Attorney General 100 W. Randolph St. Suite 12 Chicago, IL 60601 Chairman LaSalle County Board 707 Etna Road Ottawa, IL 61350 Chairman Illinois Commerce Commission 527 E. Capitol Avenue, Leland Building Springfield, IL 62706 Robert Cushing, Chief, Public Utilities Division Illinois Attorney General's Office 100 W. Randolph Street Chicago, IL 60601 Manager Licensing - Dresden, Quad Cities and Clinton Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Dresden and Quad Cities Nuclear Power Stations cc:
Site Vice President - Dresden Nuclear Power Station Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Dresden Nuclear Power Station Plant Manager Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Regulatory Assurance Manager - Dresden Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, IL 60450-9766 Chairman Grundy County Board Administration Building 1320 Union Street Morris, IL 60450 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 David C. Tubbs MidAmerican Energy Company One River Center Place 106 E. Second, P.O. Box 4350 Davenport, IA 52808-4350 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 Three Mile Island Nuclear Station, Unit 1 cc:
Site Vice President - Three Mile Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC P. O. Box 480 Middletown, PA 17057 Vice President - Operations, Mid-Atlantic AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-N Kennett Square, PA 19348 Regional Administrator Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Chairman Board of County Commissioners of Dauphin County Dauphin County Courthouse Harrisburg, PA 17120 Chairman Board of Supervisors of Londonderry Township R.D. #1, Geyers Church Road Middletown, PA 17057 Senior Resident Inspector (TMI-1)
U.S. Nuclear Regulatory Commission P.O. Box 219 Middletown, PA 17057 Director - Licensing and Regulatory Affairs AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Rich Janati, Chief Division of Nuclear Safety Bureau of Radiation Protection Department of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Plant Manager - Three Mile Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC P. O. Box 480 Middletown, PA 17057 Regulatory Assurance Manager - Three Mile Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC P.O. Box 480 Middletown, PA 17057 Peter Eselgroth, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Michael A. Schoppman Framatome ANP Suite 705 1911 North Ft. Myer Drive Rosslyn, VA 22209 Vice President, General Counsel and Secretary AmerGen Energy Company, LLC 2301 Market Street, S23-1 Philadelphia, PA 19101 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 Eric Epstein TMI Alert 4100 Hillsdale Road Harrisburg, PA 17112 Correspondence Control Desk AmerGen Energy Company, LLC P.O. Box 160 Kennett Square, PA 19348 Three Mile Island Nuclear Station, Unit 1 cc:
Manager Licensing - Three Mile Island Nuclear Station, Unit 1 Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Oyster Creek Nuclear Generating Station cc:
Site Vice President - Oyster Creek Generating Station AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731 John E. Matthews, Esquire Morgan, Lewis, & Bockius LLP 1111 Pennsylvania Avenue, NW Washington, DC 20004 Kent Tosch, Chief New Jersey Department of Environmental Protection Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 Vice President - Operations Support AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, IL 60555 H. J. Miller Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 Mayor of Lacey Township 818 West Lacey Road Forked River, NJ 08731 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 445 Forked River, NJ 08731 Manager Licensing - Oyster Creek Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Oyster Creek Generating Station Plant Manager AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731 Regulatory Assurance Manager Oyster Creek AmerGen Energy Company, LLC P.O. Box 388 Forked River, NJ 08731 Vice President, General Counsel and Secretary AmerGen Energy Company, LLC 2301 Market Street, S23-1 Philadelphia, PA 19101 Limerick Generating Station, Unit Nos. 1 and 2 cc:
Site Vice President Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Plant Manager Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Regulatory Assurance Manager - Limerick Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Manager Licensing Limerick Generating Station Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Senior Resident Inspector U.S. Nuclear Regulatory Commission Limerick Generating Station P.O. Box 596 Pottstown, PA 19464 Library U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Chief-Division of Nuclear Safety PA Dept. of Environmental Resources P.O. Box 8469 Harrisburg, PA 17105-8469 Chairman Board of Supervisors of Limerick Township 646 West Ridge Pike Linfield, PA 19468 Peach Bottom Atomic Power Station, Unit Nos. 2 and 3 cc:
Site Vice President Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Plant Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Regulatory Assurance Manager Peach Bottom Atomic Power Station Exelon Generation Company, LLC 1848 Lay Road Delta, PA 17314 Resident Inspector U.S. Nuclear Regulatory Commission Peach Bottom Atomic Power Station P.O. Box 399 Delta, PA 17314 Mr. Roland Fletcher Department of Environment Radiological Health Program 2400 Broening Highway Baltimore, MD 21224 Board of Supervisors Peach Bottom Township 545 Broad Street Ext.
Delta, PA 17314-9203 Mr. Richard McLean Power Plant and Environmental Review Division Department of Natural Resources B-3, Tawes State Office Building Annapolis, MD 21401 Manager-Financial Control & Co-Owner Affairs Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, NJ 08038-0236 Manager Licensing-Peach Bottom Atomic Power Station Exelon Generation Company, LLC 200 Exelon Way, KSA -3E Kennett Square, PA 19348
ENCLOSURE SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST TO USE ASME CODE CASE N-661 AT BRAIDWOOD UNITS 1 AND 2; BYRON UNITS 1 AND 2; CLINTON; DRESDEN UNITS 2 AND 3; LASALLE UNITS 1 AND 2; LIMERICK UNITS 1 AND 2; OYSTER CREEK; PEACH BOTTOM UNITS 2 AND 3; QUAD CITIES UNITS 1 AND 2; AND THREE MILE ISLAND UNIT 1 NUCLEAR POWER PLANTS EXELON GENERATION COMPANY, LLC AND AMERGEN ENERGY COMPANY, LLC DOCKET NUMBERS STN 50-456, STN 50-457, STN 50-454, STN 50-455, 50-461, 50-237, 50-249, 50-373, 50-374, 50-352, 50-353, 50-219, 50-277, 50-278, 50-254, 50-265 AND 50-289
1.0 INTRODUCTION
By letter (ML041210175) dated April 26, 2004, Exelon Generation Company, LLC (Exelon, the licensee), and AmerGen Energy Company, LLC (AmerGen, the licensee), requested that the NRC approve an alternative to the requirements of IWA-4120(a) and IWA-4310 of the 1989 Edition of the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code),Section XI. Similarly, the licensees also requested that the NRC approve an alternative to the requirements of IWA-4410(a) and (b) and IWA-4611.1 of the 1995 Edition through the 1996 Addenda of the ASME Code,Section XI. Specifically, the licensees requested that the NRC approve the use of ASME Code Case N-661, Alternative Requirements for Wall Thickness Restoration of Class 2 and 3 Carbon Steel Piping for Raw Water Service. Byron Station, Units 1 and 2; Braidwood Station, Units 1 and 2; LaSalle County Station, Units 1 and 2; Clinton Power Station; Peach Bottom Atomic Power Station, Units 2 and 3; and Limerick Generating Station, Units 1 and 2 are committed to the 1989 Edition of Section XI of the ASME Code. Quad Cities Nuclear Power Station, Units 1 and 2, Dresden Nuclear Power Station Units 2 and 3, Three Mile Island, Unit 1, and Oyster Creek Generating Station are committed to the 1995 Edition through the 1996 Addenda of Section XI of the ASME Code. The request was made pursuant to Section 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations (10 CFR) to address replacement or internal weld repair of wall thinning conditions resulting from various wall thinning degradation mechanisms such as erosion, corrosion, cavitation and pitting in Class 2 and 3 carbon steel raw water piping systems. The licensees' stated the primary reason for the request was to provide adequate time for additional examination of adjacent piping so that pipe replacement can be planned to reduce impact on system availability including Maintenance Rule applicability and availability of replacement materials.
The regulation at 10 CFR 50.55a(g) specifies that inservice inspection (ISI) of nuclear power plant components shall be performed in accordance with the requirements of the ASME Code,Section XI. As stated in 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph (g) may be used when authorized by the NRC if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plant Components, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first ten-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the applicable nuclear power plants is listed below:
PLANT INTERVAL EDITION Byron Station, Unit 1 Second 1989 Edition, no addenda Byron Station, Unit 2 Second 1989 Edition, no addenda Braidwood Station, Unit 1 Second 1989 Edition, no addenda Braidwood Station, Unit 2 Second 1989 Edition, no addenda Quad Cities Nuclear Power Station, Units 1 and 2 Fourth 1995 Edition through 1996 Addenda LaSalle County Station, Unit 1 Second 1989 Edition, no addenda LaSalle County Station, Unit 2 Second 1989 Edition, no addenda Clinton Power Station Second 1989 Edition, no addenda Dresden Nuclear Power Station, Units 2 and 3 Fourth 1995 Edition through 1996 Addenda Three Mile Island, Unit 1 Third 1995 Edition through 1996 Addenda Peach Bottom Atomic Power Station, Unit 2 Third 1989 Edition, no Addenda Peach Bottom Atomic Power Station, Unit 3 Third 1989 Edition, no Addenda Oyster Creek Generating Station Fourth 1995 Edition through 1996 Addenda Limerick Generating Station, Units 1 and 2 Second 1989 Edition, no Addenda 2.0 LICENSEES PROPOSED ALTERNATIVE ASME Code Components Affected All ASME Class 2 and 3 carbon steel plant raw water piping systems.
Applicable Code Requirement
ASME Code,Section XI, IWA-4120(a) of the 1989 Edition (or IWA-4410(a)(b) of the 1995 Edition through 1996 Addenda) requires that the repairs be performed in accordance with the Owners Design Specification/Owners Requirements and the original or later Construction Code of the component or system.
ASME Code,Section XI, IWA-4310 of the 1989 Edition (or IWA 4611.1 of the 1995 Edition through 1996 Addenda) requires that the defect be removed or reduced in size in accordance with Article IWA-4000.
Reason for Request
Relief is requested from replacement or internal weld repair of wall thinning conditions resulting from various wall thinning degradation mechanisms such as erosion, corrosion, cavitation, and pitting in Class 2 and 3 carbon steel raw water piping systems in accordance with the design specification/owners requirements and the original construction code. The licensee stated the primary reason for this request is to provide adequate time for additional examination of adjacent piping so that pipe replacement can be planned to reduce impact on system availability including Maintenance Rule applicability and availability of replacement materials.
Proposed Alternative and Basis for Use Exelon and AmerGen will implement the requirements of ASME Code Case N-661 for Class 2 and 3 plant raw water piping system repairs resulting from degradation mechanisms such as erosion, corrosion, cavitation, or pitting as an alternative to the requirements of IWA-4000. The licensee stated that these types of defects are typically identified by the discovery of small leaks in the piping system or by pre-emptive examinations performed by the licensee to monitor the degradation mechanisms but which are not required by the ASME Code. The alternative repair technique described in Code Case N-661 involves the application of additional weld metal on the exterior of the piping system, which restores the wall thickness to its required value. The licensee stated that this repair technique will be utilized whenever the engineering evaluation determines that such a repair is suitable for the particular defect or degradation being resolved.
The licensee stated that provisions for use of this Code Case will be addressed in the Repair and Replacement Program.
The licensee stated that the provisions will provide that adjacent areas be examined to verify that the entire flawed area will be encompassed by the repair and that there are no other unacceptable degraded locations within a representative area, which is dependent on the degradation mechanism present. The licensee will perform an evaluation of the degradation mechanism to determine the re-examination schedule to be performed over the life of the repair.
The repair will be considered to have a maximum service life of two fuel cycles unless examinations during each of the two fuel cycles are performed to establish the expected life of the repair.
Additionally, the licensee stated that the following restrictions will be placed on the use of Code Case N-661, to assure that the use of the Code Case will provide an acceptable alternative pursuant to 10 CFR 50.55a(a)(3)(i):
(a)
If the cause of the degradation has not been determined, the repair is only acceptable for one cycle.
(b)
Weld overlay repair of an area can only be performed once in the same location.
(c)
When through-wall repairs are made by welding on surfaces that are wet or exposed to water, the weld overlay repair is only acceptable until the next refueling outage.
The licensees state that the basis for use of the repair technique described in Code Case N-661 is that Section XI of the ASME Code determined that this repair technique provides an acceptable alternative to the requirements of IWA-4000 and provides an acceptable level of quality and safety. Therefore, the licensees conclude that the proposed alternative is justified per 10 CFR 50.55a(a)(3)(i).
Code Case N-661 was approved by the ASME Section XI Code on July 23, 2002. However, it has not been incorporated into 10 CFR 50.55a and thus is not available for application at nuclear power plants without specific NRC approval. Therefore, Exelon and AmerGen are documenting the request to apply the alternative repair technique described in the Code Case via this relief request.
Duration of Proposed Alternative The proposed alternative is for the use of the remainder of each plants ten year ISI interval, or until the NRC publishes Code Case N-661 in a future revision of 10 CFR 50.55a.
3.0 STAFF EVALUATION By letter dated April 26, 2004, Exelon and AmerGen requested that the NRC approve an alternative to the requirements of IWA-4120(a) and IWA-4310 of the 1989 Edition of the ASME Code Section XI, and IWA-4410(a)(b) and IWA-4611.1 of the 1995 Edition through 1996 Addenda of the ASME Code Section XI. Specifically, the licensees requested that the NRC approve ASME Code Case N-661 for use at Braidwood Station, Units 1 and 2; Byron Station, Units 1 and 2; Clinton Power Station; Dresden Nuclear Power Station, Units 2 and 3; LaSalle County Station, Units 1 and 2; Limerick Generating Station, Units 1 and 2; Oyster Creek Generating Station; Peach Bottom Atomic Power Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1 and 2; and Three Mile Island, Unit 1. The request was made pursuant to 10 CFR 50.55a(a)(3)(i) to address replacement or internal weld repair of wall thinning conditions resulting from various wall thinning degradation mechanisms such as erosion, corrosion, cavitation, and pitting in class 2 and 3 carbon steel raw water piping systems. The licensees' stated reason for the request was to provide adequate time for additional examination of adjacent piping so that pipe replacement can be planned to reduce impact on system availability and availability of replacement materials.
IWA-4120(a) and IWA-4410(a)(b) of the 1989 Edition and 1995 Edition through 1996 Addenda, respectively, of the ASME Code Section XI, require that repairs be performed in accordance with the Owners Design Specification and original Construction Code of the component or system. IWA-4310 and IWA-4611.1 of the 1989 Edition and 1995 Edition through 1996 Addenda, respectively, of the ASME Code Section XI, require that the defect be removed or reduced in size in accordance with Article 4000. The licensee is proposing to use the provisions of Code Case N-661 to perform an alternative repair of degraded components which involves the application of weld metal overlay on the exterior of the piping system to restore the wall thickness of the component. The licensee stated that this repair technique will be utilized whenever engineering evaluations determine that such a repair is suitable for the particular defect or degradation being resolved. Provisions for use of this Code Case will be addressed in the licensees Repair and Replacement Program. The licensee stated that those provisions will provide that adjacent areas be examined to verify that the entire flawed area will be encompassed by the repair and that there are no other unacceptable degraded locations within a representative area dependent on the degradation mechanism present. An evaluation of the degradation mechanism will be performed by the licensee to determine the re-examination schedule to be performed over the life of the repair. The licensee stated the repair will be considered to have a maximum service life of two fuel cycles unless examinations during each of the two fuel cycles are performed to establish the expected life of the repair.
The staff finds the licensees reasoning in support of its request for relief acceptable. This finding is based on the staffs prior review of Code Case N-661 and the staffs conclusion that the Code Case be approved for inclusion in Regulatory Guide 1.147 as described below..
As part of the staffs previous review of the Code Case, the following three areas of concern were identified:
(a)
If the root cause of the degradation has not been determined, a suitable reinspection frequency cannot be established.
(b)
Weld overlay repair of an area can only be performed once to ensure that ineffective repairs are not being repeatedly implemented in the same location.
(c)
Performing through-wall weld repairs on surfaces that are wet or exposed to water would produce welds that include weld defects such as porosity, lack of fusion, and cracks. It is highly unlikely that a weld can be made on an open root joint with water present on the backside of the weld without having several weld defects.
These types of weld defects can, and many times do, lead to premature failure of a weld joint.
Due to the above concerns, the staff concluded that certain conditions must be implemented that restrict use of the Code Case. The staff believes that use of the Code Case combined with the conditions listed below is justified because (1) use of the Code Case is restricted to low pressure raw water systems, (2) repairs are limited to minor piping system degradation (e.g.,
pipe thinning or pin-hole through wall leakage), (3) weld overlays that restore the original piping thickness must be inspected for quality upon completion of the weld as addressed in the Code Case, and (4) the Code Case repairs are only temporary and further limited by the conditions set forth by the staff. The following conditions, which correspond to the staffs concerns identified above, were proposed by the licensee and found acceptable by the staff:
(a)
If the root cause of the degradation has not been determined, the repair is only acceptable for one cycle.
(b)
Weld overlay repair of an area can only be performed once in the same location.
(c)
When through-wall repairs are made by welding on surfaces that are wet or exposed to water, the weld overlay is only acceptable until the next refueling outage.
4.0 CONCLUSION
Based on the foregoing, the NRC staff concludes that the licensee has provided an acceptable alternative to the requirements of IWA-4120(a) of the 1989 Edition (or IWA-4410(a) and (b) of the 1995 Edition through 1996 Addenda) of ASME Code,Section XI, and IWA-4310 of 1989 Edition (or IWA-4611.1 of the 1995 Edition through 1996 Addenda) of ASME Code Section XI, subject to the following three conditions which were proposed in the licensees application and must be met when using Code Case N-661. These conditions are: (a) if the root cause of the degradation has not been determined, the repair is only acceptable for one cycle, (b) weld overlay repair of an area can only be performed once in the same location and (c) when through-wall repairs are made by welding on surfaces that are wet or exposed to water, the weld overlay repair is only acceptable until the next refueling outage.
The staff concludes that the proposed alternative, as supplemented by the three conditions listed above, provides reasonable assurance of structural integrity and an acceptable level of quality and safety. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for Braidwood Station, Units 1 and 2; Byron Station, Units 1 and 2; Clinton Power Station; Dresden Nuclear Power Station, Units 2 and 3; LaSalle County Station, Units 1 and 2; Oyster Creek Generating Station; Peach Bottom Atomic Power Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1 and 2; Three Mile Island, Unit 1; and Limerick Generating Station, Units 1 and 2, for each plant specific current 10-year ISI interval, or until Code Case N-661 is approved for general use by reference in 10 CFR 50.55a. After that time, the licensee must follow the conditions, if any, specified in the appropriate revision of Regulatory Guide 1.147, as incorporated into the rule. All other ASME Code,Section XI, requirements for which relief was not specifically requested and authorized herein by the NRC staff remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: Eric Reichelt, EMCB/DE Date: October 1, 2004