ML20217N510
| ML20217N510 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/30/1998 |
| From: | Mccoy C SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-06, GL-97-6, LCV-1176, NUDOCS 9804090118 | |
| Download: ML20217N510 (5) | |
Text
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C. K. McCoy -
Soutliern Noclear.
Vice President
_ Operating Conipeny,Inc.
Vogtle Project 40 Inverness Center Parkway P.O. Box 1295
" Birmingham, Alabama 35201
' Tel 205.992.7122 Fax 205.992.0403 SOUTHERN COMPANY
' March 30, 1998.
Eurgy ro ServeYourWorlP LCV-1176 Docket Nos.: 50-424,
50-425 U. S. Nuclear Regulatory Commission ~
~ ATTN: Document Control Desk Washington, DC 20555-0001 Ladies and Gentlemen:
VOGTLE ELECTRIC GENERATING PLANT 90-DAY RESPONSE TO GENERIC LETTER 97-06
" DEGRADATION OF STEAM GENERATOR INTERNALS" On December 30,1997 the Nuclear Regulatory Commission (NRC) issued Generic Letter
-(G.L.) 97-06, " Degradation of Steam Generator Internals". This letter was issued to: (1) communicate findings of damage to steam generator internals at foreign PWR facilities; (2) alert licensees to recent findings of damage to tube support plates at a U.S. PWR facility; (3) emphasize the importance of performing comprehensive examinations of steam generator internals to ensure stmetural integrity is maintained in accordance with 10 CFR Part 50 Appendix B requirements; and (4) request information necessary to ensure that each facility is in compliance with its current licensing bases.
Vogtle Electric Generating Plant (VEGP) intends to follow the requirements of NEI 97-06, " Steam Generator Program Guidelines," although this intention should not be regarded as a regulatory commitment. The nuclear power industry recently adopted an initiative requiring each utility to meet the intent of the guidance provided in NEI 97-06,
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no later than the first refueling outage after January 1,1999. As discussed in NEI 97-06, each utility is required to monitor secondary side steam generator components if their failure could prevent the steam generator from fulfilling its intended safety-related function.
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The VEGP-specific information is provided as an attachment to this letter as requested by G.L. 97-06.
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9804090118 980330 PDR ADOCK 05000424
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. U. S. Nuclear Regulatory Commission Page 2 Mr. C. K.' McCoy states that he is a sice president of Southern Nuclear Operating Company and is authorized to execute this oath on behalfof Southern Nuclear Operating Company and that, to the best of his knowledge and belief, the facts set forth in this letter and attachment are true.
SOUTHERN NUCLEAR OPERATING CO PANY By:
C. K. McCo Sworn to and subscribed belbre me thishay of d
.1998.
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h, 04 Notary Public CKM/BHW/gmb Attachment xc: Southern Nuclear Mr. J. B. Beasley Mr. M. Sheibani NORMS U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. D. H. Jaffe, Senior Project Manager, NRR Mr. J. Zeiler, Senior Resident Inspector, Vagtle State of Georgia Mr. L. C. Barrett, Commissioner, Department of Natural Resources
ATTACHMENT i.
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VOGTLE ELECTRIC GENERATING PLANT RESPONSE TO GENERIC LETTER 97-06 Backaround
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. In response to the issuance of a proposed generic letter on degradation of steam generator internals, the Nuclear Energy Institute (NEI) formed the Steam Generator Internals Task Force in January 1997. The purpose of the task force was to develop a coordinated industry-wide response to the secondary-side degradation issues identified in the proposed generic letter. Participation on this task force included the Electric Power Rcsearch Institute (EPRI), licensees, and representatives of the owner's groups for each domestic L
l steam generator design. The NEI task force met with the NRC in May 1997 to gain ~ a better understanding of the safety concerns discussed in the generic letter. As a result of i-these efforts, the owners groups developed preliminary safety and susceptibility assessments relative to the design and operating history of their units.
Each owner's group initiated a program to assist its respective owners in assessing the susceptibility to tube damage and loss of decay heat removal capability due to secondary-side degradation. An integral component of this assessment was an appreciation of the applicability for degradation in domestic steam generators as compared to that found in the French units. EPRI responded to this need and with the assistance of Electricite de France (EdF) developed the report, GC-109558, " Steam Generator Internals Degradation:
1 Modes ofDegradation in EdF Units."
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The EPRI report provides evaluations of the causal factors involved in the modes'of degradation experienced in the French units. The owners groups used this report to gain insights into the applicability of the French experience to their steam generator designs and operating histcry. NEI transmitted this report to the NRC via a letter dated December 19, 1997.. EPRI provided copies directly to Steam Generator Management Program i
Technical Advisory Group representatives.
In addition to the review of the EdF degradation causal factors, the susceptibility t
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assessments included consideration of: design factors; fabrication and manufacturing
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techniques; plant operating history including chemistry; plant inspection experience; and Lj related degradation such as denting. As part of the inspection experience review, the L
~ owner's groups compiled and assessed collective visual, video and pertinent NDE inspection experience information to further enhance their evaluations regarding the susceptibility to internals degradation.
Based on inspection results, Westinghouse Owner's Group (WOG) WCAP-15002,
" Evaluation of EdF Steam Generator Internals Degradation - Impact of Casual Factors on Westinghouse 51 Series Steam Generator ", dated December 1997, concludes that the causal factors identified by EdF do notjeopardize the continued operability of Series 51 P
steam generators. A similar detailed evaluation for the Model F steam generator is
.s presently being performed by the WOG. The results of this evaluation are scheduled to.be provided to the NRC via an NEI letter by the end of May 1998.
The industry, through the focused efforts of the NEI task force, has provided guidance and information necessary for licensees to adequately address the potential issues regarding steam generator internals degradation. The responses provided below address the requirements of G.L. 97-06 for VEGP.
I G.L. 97-06 Item 1 l
(1) A discussion of any program in place to detect degradation of steam generator internals and descriptive inspection plaru, including the inspection scope, frequency, methods and equipment. The G.L. requires discussions to include the following information for each facility:
l (a) Whether inspection records at the facility have been reviewed for indications of tube support plate signal anomalies from eddy-current testing of the steam generator tubes that may be indicative of support plate damage or ligament cracking.
(b) Whether visual or video camera inspections on the secondary side of the steam generators have been performed at the facility to gain information on the condition of the steam generator internals (e.g., support plates, tube bundle wrappers, or other componentr).
(c) Whether dqradation of steam generator internals has been detected at the facility, and how the degradation was addressed and dispositioned.
VEGP Response to Item i Eddy current testing has not been used at VEGP for detection of steam generator internals degradation. A variety of techniques have been utilized for the timely detection of 1
degradation as described below:
Tube Sheet Area: VEGP performs remote visual inspections of the tubesheet as part of the Foreign Object Search and Retrieval inspections conducted on each steam generator every refueling outage. In conjunction with these inspections, internal structures adjacent to the tubesheet are inspected. These inspections have not identified any signs of degradation. These steam generator inspections will continue during refueling outages.
Support Plates: Since 1993 VEGP has performed upper support inspections utilizing a remote camera system. During the last Unit I seventh refueling outage, an upper bundle l
inspection was performed on the support plate for one steam generator. No signs of degradation were observed. It is planned to continue these inspections during future l
refueling outages.
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bpper In'ternals, Feedwater Ring, and J-Nozzles: Starting with the Units 1 and 2 third refueling outages, visual inspections or ultrasonic testing have been used to search for degradation in these components. Ilowever, no degradation has been observed. The current plan is for these inspections to continue on steam generators during refueling outages.
Feedwater Ring Backing Ring: Starting in the year 2000 for Unit I and 2002 for Unit 2, the feedwater ring backing ring for all steam generators will be NDE inspected once every five refueling outages.
G.L. 97-06 Item 2 i
(2) If the addressee currently has no program in place to detect degradation of steam l-generator internals, a discussion and justification of the plans and schedule for establishing such a program, or why no program is needed.
VEGP Response to item 2 As described above, VEGP does have a program in place to detect degradation of steam generator internals. Therefore, Item 2 does not apply.
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