ML030690512
| ML030690512 | |
| Person / Time | |
|---|---|
| Site: | PROJ0690 |
| Issue date: | 03/10/2003 |
| From: | Matthews D Division of Regulatory Improvement Programs |
| To: | Lochbaum D, Alexis Nelson Nuclear Energy Institute, Union of Concerned Scientists |
| Kang P, NRR/DRIP/RLEP, 415-2779 | |
| References | |
| +KBR1SISP20050608, ISG-5, NUREG-1800, NUREG-1801 | |
| Download: ML030690512 (7) | |
Text
March 10, 2003Mr. Alan NelsonNuclear Energy Institute 1776 I Street, NW., Suite 400 Washington, DC 20006-3708Mr. David LochbaumUnion of Concerned Scientists 1707 H Street, NW., Suite 600 Washington, DC 20006-3919
SUBJECT:
INTERIM STAFF GUIDANCE (ISG) - 5 ON THE IDENTIFICATION ANDTREATMENT OF ELECTRICAL FUSE HOLDERS FOR LICENSE RENEWAL
Dear Messrs. Nelson and Lochbaum:
The Nuclear Regulatory Commission (NRC) staff (Staff) has finalized the proposed ISG on theidentification and treatment of electrical fuse holders for license renewal that was issued on May 16, 2002. The Staff considered comments from a Nuclear Energy Institute (NEI) letter, dated June 19, 2002, and a Union of Concerned Scientists letter, dated May 23, 2002. Based on insights gained during the Staff's review of license renewal applications, the Staff finds that the previous ISG is sufficient to address the aging effects on insulation material for fuse blocks, but not sufficient to detect the aging effects on metallic clamps for the fuse clips of the fuse holder. Thus, the revised ISG concludes that both the insulation material and the metallic clamps of fuse holders are subject to aging management for license renewal. Enclosure 1 is a copy of the revised ISG for fuse holders. Enclosure 2 includes pertinentchanges to (1) Chapter VI of "Generic Aging Lessons Learned (GALL) Report" (NUREG-1801) and (2) Table 2.1-5 of "Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants" (NUREG-1800). The Staff is currently developing an appropriate aging management program for metallic metal clips which will be incorporated into NUREG-1801.The implementation of this Staff position will start with the license renewal applications currentlyunder review. In response to comments on the implementation of ISG issues for plants with a renewed license during the license renewal steering committee meeting on February 12, 2003, the Staff has initiated discussion with the Committee to Review Generic Requirements on potential backfit implications. Staff guidance for implementation of the Staff position at plants with a renewed license will be issued separately.
A. Nelson and D. Lochbaum- 2 -For the resolved ISGs, it is also possible that comparable changes might need to be made toNEI 95-10, Revision 3, "Industry Guidance for Implementing the Requirements of10 CFR Part 54 - The License Renewal Rule.
" If you have any questions regarding this matter,please contact Peter Kang at 301-415-2779.Sincerely, /RA/David B. Matthews, DirectorDivision of Regulatory Improvement Programs Office of Nuclear Reactor RegulationProject No. 690
Enclosures:
As stated cc w/encls: See next page A. Nelson and D. Lochbaum- 2 -For the resolved ISGs, it is also possible that comparable changes might need to be made toNEI 95-10, Revision 3, "Industry Guidance for Implementing the Requirements of10 CFR Part 54 - The License Renewal Rule.
" If you have any questions regarding this matter,please contact Peter Kang at 301-415-2779.Sincerely, /RA/David B. Matthews, DirectorDivision of Regulatory Improvement Programs Office of Nuclear Reactor RegulationProject No. 690
Enclosures:
As stated cc w/encls: See next pageDISTRIBUTION
- See next pageC:\ORPCheckout\FileNET\ML030690512.wpd OFFICEPM:RLEP:DRIPLA:RLEP:DRIPSC:RLEP:DRIPBC:DE:EEIBNAMEPKangHBerillaSLeeJCalvo DATE1/29/031/30/031/30/031/31/03 OFFICED:DEOGCPD:RLEP:DRIPD:DRIP NAMERBarrettAFernandezPTKuoDMatthews DATE2/3/032/20/032/24/033/10 /03OFFICIAL RECORD COPY DISTRIBUTION: Letter to A. Nelson & D. Lochbaum RE: ISG-5, Dated: March 10, 2003 Package: ML030690492 HARD COPY RLEP RFP. KangHARD COPY RLEP RFProject ManagerE-MAIL:PUBLICW. Borchardt D. Matthews F. Gillespie RidsNrrDe E. Imbro G. Bagchi K. Manoly W. Bateman J. Calvo C. Holden H. Nieh G. Holahan H. Walker S. Black B. Boger D. Thatcher R. Pettis G. Galletti C. Li J. Moore R. Weisman M. Mayfield A. Murphy W. McDowell S. Smith (srs3)
T. Kobetz R. Assa C. Munson RLEP Staff
A. Thadani C. Julian R. Gardner M. Farber M. Modes J. Vora INTERIM STAFF GUIDANCE (ISG)-5 ON THE IDENTIFICATION AND TREATMENT OF ELECTRICAL FUSE HOLDERS FOR LICENSE RENEWALStaff PositionConsistent with the requirements specified in 10 CFR 54.4(a), fuse holders (including fuse clipsand fuse blocks) are considered to be passive electrical components. Fuse holders would be scoped, screened, and included in the aging management review (AMR) in the same manner as terminal blocks and other types of electrical connections that are currently being treated in the process. This staff position only applies to fuse holders that are not part of a larger assembly, but support safety-related and non safety-related functions in which the failure of a fuse precludes a safety function from being accomplished [10 CFR Part 54.4(a)(1) and (a)(2)].
Examples are fuses that are used as protective devices to ensure the integrity of containment electrical penetrations when they are challenged by electrical faults, or as isolation devices between Class 1E and non-Class 1E electrical circuits to ensure that the safety function is not compromised as a result of faults in the non-Class 1E circuits. An appropriate aging management program (AMP) should be adopted to manage the effects of aging where necessary.RationaleThe intended functions of a fuse holder are to provide mechanical support for the fuse and tomaintain electrical contact with the fuse blades or metal end caps to prevent the disruption of the current path during normal operating conditions when the circuit current is at or below the current rating of the fuse. Fuse holders perform the same primary function as connections; they provide electrical connections to specified sections of an electrical circuit to deliver rated voltage, current, or signals. The intended functions of fuse holders meet the criteria of 10 CFR 54.4(a) and are performed without moving parts or without a change in configuration or properties as described in 10 CFR 54.21(a)(1)(i). The staff concludes that fuse holders are passive, long-lived electrical components within the scope of license renewal and subject to an AMR. However, fuse holders inside the enclosure of an active component, such as switchgear, power supplies, power inverters, battery chargers, and circuit boards, are considered to be piece parts of the larger assembly. Therefore, under 10 CFR 54.21, fuse holders that are parts of a larger assembly are considered outside the scope for license renewal.For license renewal purposes, fuse holders/blocks are classified as a specialized type ofterminal block because of the similarity in design and construction. Terminal blocks are passive components subject to an AMR for license renewal. However, like fuses, terminal blocks located inside the enclosure of an active component are considered to be piece parts of the larger assembly and, thus, are outside the scope of license renewal. The fuse holders are typically constructed of blocks of rigid insulating material, such as phenolic resins. Metallic clamps are attached to the blocks to hold each end of the fuse. The clamps can be spring-loaded clips that allow the fuse ferrules or blades to slip in, or they can be bolt lugs, to which the fuse ends are bolted. The clamps are typically made of copper. Enclosure 1 Operational experience, as discussed in NUREG-1760 (Aging Assessment of Safety-RelatedFuses Used in Low- and Medium-Voltage Applications in Nuclear Power Plants), identified fuse holders as experiencing a number of age-related failures. Aging stressors such as vibration, thermal cycling, electrical transients, mechanical stress, fatigue, corrosion, chemical contamination, or oxidation of the connecting surfaces can result in fuse holder failure. On this basis, fuse holders (including both the insulation material and the metallic clamps) are subject to both an AMR and AMP for license renewal. Typical plant effects observed from fuse holder failures due to aging have resulted in: challenges to safety systems, cable insulation failure due to over-temperature, failure of a containment spray pump to start, a reactor trip, etc. Therefore, managing age-related failures of fuse holders would have a positive effect on the safety performance of a plant. Information Notices 91-78, 87-42, and 86-87 provide examples that underscore the safety significance of fuse holders and the potential problems that can arise from age-related fuse holder failures.GALL AMP for Fuse HoldersFuse holders, are considered as electrical connections and, thus, are subject to GALL XI.E1 "Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental QualificationRequirements.
" However, the AMP for fuse holders needs to include the following agingstressors, if applicable: fatigue, mechanical stress, vibration, chemical contamination, and corrosion. Where environments or operating conditions preclude such aging effects (e.g., fuse holders not subject to vibration from rotating machinery), they need not be addressed by the AMP. GALL XI.E1 is based on only a visual inspection of accessible cables and connections.
Visual inspection, alone, may not be sufficient to detect the aging effects from fatigue, mechanical stress, vibration, or corrosion on the metallic clamps of the fuse holder. Other methods of aging detection may be necessary. Alternatively, plant modifications or administrative controls that have been made, which preclude these types of aging effects from occurring, would eliminate the need for an additional AMP (i.e., the GALL XI.E1 program will be adequate).
NUCLEAR ENERGY INSTITUTE Project No. 690
cc:Mr. Joe BartellU.S. Department of Energy NE-42 Washington, DC 20585Ms. Christine S. SalembierCommissioner State Liaison Officer Department of Public Service 112 State St., Drawer 20 Montipelier, VT 05620-2601Mr. Stephen T. HaleFlorida Power & Light Company 9760 S.W. 344 St.
Florida City, FL 33035Mr. William CorbinVirginia Electric & Power Company Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, VA 23060Mr. Frederick W. PolaskiManager License Renewal Exelon Corporation 200 Exelon Way Kennett Square, PA 19348George WrobelManager, License Renewal R.E. Ginna Nuclear Power Plant 1503 Lake Rd.
Ontario, NY 14519Ronald B. ClaryManager, Plant Life Extension V.C. Summer Nuclear Station Bradham Blvd.
P.O. Box 88 Jenkinsville, SC 29065Mr. Robert GillDuke Energy Corporation Mail Stop EC-12R P.O. Box 1006 Charlotte, NC 28201-1006Mr. John B. HermanManager - Nuclear Licensing Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.
Post Office Box 550 Fort Calhoun, NE 68023-0550Mr. Paul GunterDirector of the Reactor Watchdog Project Nuclear Information & Resource Service
1424 16 th St., NW, Suite 404Washington, DC 20036Mr. Hugh JacksonPublic Citizen
's Critical Mass Energy & Environment Program 215 Pennsylvania Ave., SE Washington, DC 20003Mary OlsonNuclear Information & Resource Service Southeast Office P.O. Box 7586 Asheville, NC 28802 Talmage B. ClementsManager - License Renewal Nuclear Engineering Services
CP&L 410 South Wilmington St.
Raleigh, NC 27602