ML20206D189
| ML20206D189 | |
| Person / Time | |
|---|---|
| Issue date: | 04/27/1999 |
| From: | Charemagne Grimes NRC (Affiliation Not Assigned) |
| To: | Walters D NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| PROJECT-690 NUDOCS 9905040015 | |
| Download: ML20206D189 (6) | |
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April 27, 1999
'O Mr. Douglas J. Walters Nuclear Energy Institute i
1776 i Street, N.W, Suite 400 Washington, DC 20006-3708
SUBJECT:
LICENSE RENEWAL ISSUE NO. 98-0016, " AGING MANAGEMENT REVIEW OF FUSES"
Dear Mr. Walters:
Enclosed is the staff's evaluation and proposed resolution for the subject issue. The staff pirans to implement the recommended resolution as part of the next revision to the " Standard Review Plan for License Renewal." We also expect NEl 95-10, " Industry Guideline for l
Implementating the Requirements of 10 CFR Part 54 ' The License Renewal Rule," to be revised to reflect the guidance provided in that attached staff position. Accordingly, if there are any industry comments on the evaluation basis or the proposed resolution, we request that you document those comments within 30 days following your receipt of this letter, to ensure a timely l
resolution of this issue. If you have any questions regarding this matter, please contact Robert l
Prato at 301-415-1147.
Sincerely, l
Christopher. Grim s, Chief License Renewal and Standardization Branch Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation
. Project: 690
Enclosure:
As stated cc w/ enclosure:
See next page
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-(License Renewal Steering Committee)
Project No. 690 cc:
Mr. Dennis Harrison Mr. Robert Gill U.S. Department of Energy Duke Energy Corporation NE-42 Mail Stop EC-12R Washington, D.C. 20585 P.O. Box 1006 Charlotte, NC 28201-1006 Mr. Ricard P. Sedano, Commissioner Mr. Charles R. Pierce State Uaison Officer Southern Nuclear Operating Co.
Department of Public Service 40 inverness Center Parkway 112 State Street BIN B064 Drawer 20 Birmingham, AL 35242 Montipelier, Vermont 05620-2601 Mr. Douglas J. Walters Mr. Barth Doroshuk l
Nuclear Energy Institute Baltimore Gas & Electric Company
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1776 l Street, N.W.
1650 Calvert Cliffs Parkway l
Washington, DC 20006 Lusby, Maryland 20657-47027 DJW@NEl.ORG National Whistleblower Center Chattooga River Watershed Coalition 3233 P Street, N.W.
P. O. Box 2006 Washington, DC 20007 Clayton, GA 30525 l
Mr. William H. Mackay Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 GSB-2E Russellville, Arkansas 72802 l
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Distribution:
Hard coov PUBLIC Docket File;!
RLSB RF N. Dudley, ACRS - T2E26 E-mail:
R. Zimmerman i
W. Kane D. Matthews S. Newberry C. Grimes C. Carpenter B. Zalcman J. Strosnider R. Wessman E. Imbro W. Bateman J. Calvo H. Brammer T. Hiltz G. Holahan T. Collins C. Gratton B.Boger R. Correia R. Latta J. Moore J, Rutberg R. Weisman M. Zobler M, Mayfield S. Bahadur i
A. Murphy D. Martin W. McDowell S. Droggitis RLSB Staff G. Tracy A. Thadani C. Julian i
P. Shemanski D. Thatcher l
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Finally, the Statements of Consideration contains the following discussion:
The previous license renewal rule required an applicant forlicense renewal to identify, from systems, structures, and components important to license renewal, those structures and components that contribute to the performance of a ' required function" or could, if they fail, prevent systems, structures, and components from performing a " required function." This requirement initially posed
' some difficulty in conducting pro-application reviews of proposed scoping methodologies because it was not clear what was meant by " required function." Most systems, structures, and components have more than one function and each could be regarded as
" required." Although the Commission could have required a licensee to ensure allfunctions of a system, strJClure, or component as part of the aging management review, the Commission concluded that this requirement would be unreasonable andinconsistent with the Commission's original intent to focus only on those systems, structures, and components of primaryimportance to safety. Consideration of ancillary functions would expand the scope of the license renewal review beyond the Commission's intent. Therefore, the Commission determined that " required function"in the previous license renewal rule refers to thnse functions that are responsible for causing the systems, structures, and components to be consideredimportant to license renewal.
In the SOC, the Commission distinguished between functions that are of primary importance to safety and those tha't may be ancillary. Fuses may perform both kinds of functions. The staff has evaluated whether fuses require an aging management review, based on its applications in Nuclear Power Plant electrical systems and the two distinct functions they may perform.
1.
A fuse can be included in an electrical system to provide a function directly related to nuclear power plant safety such as containment integrity protection (i.e.
to limit fault damage to a containment electrical penetration) or to provide isolation protection for the Class 1E portion of the electrical system (i.e. to protect Class 1E electric equipment from faults originating in non-Class 1E equipment). Fuses included in nuclear power plant systems to perform such functions are intended to prevent or mitigate the consequences of accidents that could result in potential exposure comparable to the guidelines in 9 50.34(a)(1) or 6100.11 of the Commission) regulations. Such fuses perform functions that me defined as
" safety-related"in 10 CFR $ 54.4(a)(1), and are, therefore, winin the scope of license renewal.
Backaround On September 19,1997, the staff issued a position (Attachment 1) on five electrical components including fuses. On April 10,1999, NEl issued a response (Attachment 2) to this position. In this letter, NEl agreed with the staffs positions with the exception of the staffs determination that fuses require an aging management review. In response to NEl's position, the staff reviewed its determination that fuses are passive, long-lived components requiring an aging mansgement review. The following are the results of the staffs review and its current position on the matter of fuses.
Evaluation The April 10,1998, letter, contains the following conclusions:
1.
" Table 4.1-1in NEI 95-10 is entitled " Typical Passive Structure and l
Component Intended Functions." The purpose of this table is to identify typicalintended functions forlong-lived passive structures and components. As a result of discussions between NEI and the NRC staff we specifically included the intended function, ' Provide insulation resistance to preclude shorts, grounds and unacceptable leakage current," to address electrical cables and connections.
Electrical cables and connections are the only two items identified in f54.21(a)(1)(i) that require an aging management review because they are " passive" components. Electricalcontinuityis not included as an intended function of electrical cables and connections. Therefore, it is our view that ' electrical continuity"is not an intended function of other components identified."
2.
- lt is our position that electrical continuity is not an intended function" of fuses.
The staff disagrees with the general conclusion that " electrical continuity" is not an intended function of electrical components as is stated in item 1. In its April 10,1998 letter, NEl stated that " continuity during non-fault conditions is a function of all electrical components." The staff agrees that continuity is a function of most electrical components, including fuses, that should be assessed for its importance to license renewal prior to making a determination that an aging management review is not required. The following is the basis for the staffs conclusion:
Table 4.1-1 is a list of typicalintended functions and was never intended to be all inclusive.
The list of structures and components requiring an aging management review under
$54.21(a)(1)(i) is also not intended to be a complete list of " passive" structures and components. The rule clearly states that the list in question " include, but are not limited to" the structures and components contained in that list.
Enclosure
i-3 I
Fuses having the intended safety-related functions identified above perform those functions with a change iri configuration and, pursuant to 10 CFR 54.21(a)(1)(i),
are not subject to an aging management review. The continuity function of such fuses, however, is not the reason for their inclusion in nuclear power plant systems. Rather, the isolation function of these fuses is of primary importance to safety and the reason for their inclusion in systems. Continuity is merely an ancillary function in these applications, Accordingly, such fuses do not require an aging management review.
It should be noted that the staff also considered potential aging mechanisms that may l
prevent a fuse from completing its safety-related fault protection function. Because of the fact that a change in configuration is required in the performance of this function, the staff will not pursue this concem under 10 CFR Part 54. However, because of its potential safety significance, and the fact that this concem may be equally important to current licensing terms, the staff intends to assess this issue to determine if it should be a Generic Safety issue under 10 CFR Part 50.
(2)
A fuse may also be included in an electrical system solely to limit the potential extent of fault damage (e.g. branch circuit protection) and thus increase the availability or reliability of the overall electrical system. Such fuses are installed -
essentially as equipment protection devices. Such fuses perform this function with a change in configuration as in (1) above and are not subject to an aging management review.
In addition, the continuity function of such fuses is not the reason for their inclusion in nuclear power plant systems. As such, the continuity function is merely an ancillary function in these applications. Accordingly, such fuses do not require an aging management review.
4 Conclusion As set forth above, the staff has concluded that fuses do not require an aging management review under 10 CFR 54.21(a)(1). This item is considered resolved.
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+,....,o September 19, 1997 Mr. Douglas J. Walters Nuclear Energy Institute 1776 I Street. NW Suite 300 Washington, DC 20585
SUBJECT:
DETERMINATION OF AGING MANAGEMENT REVIEW FOR ELECTRICAL COMPONENTS
Dear Mr. Walters:
During the Nuclear Regulatory Comission steff's review of the Nuclear Energy i
Institute's NEI 95-10. " Industry Guideline for Implementing the Requirements of 10 CFR Part 54 - The License Renewal Rule." the need was identified for guidance on whether selected electrical components are subject to an aging management review.
NEI addressed a number of the components in its letter dated December 24. 1996. Consistent with the staff's approach in its February 27, 1997, letter to provide positions on significant issues associated with the license renewal regulatory guide and NEI 95-10 enclosed please find the staff's position on the aging management review requirements i
for selected electrical components.
The recommendations in the enclosed j
position should be considered when revising NEI 95-10.
Sincerely.
C..L M
Christopher I. Grimes. Director License Renewal Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Project 690
Enclosure:
As stated cc: w/ encl: See next page m
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NUCLEAR ENERGY INSTITUTE (NEI)
Project No. 690 cc: Mr. Dennis Harrison U.S. Department of Energy l
NE-42 Washington. DC 20585 Mr. Douglas J. Walters Nuclear Energy Institute 1776 I Street. NW Suite 300 Washington, DC 20006 l
Mr. Richard P. Sedano. Comissioner State Liaison Officer State of Vermont Department of Public Service l
112 State Street Drawer 20 l
Montpelier. Vermont 05620-2601 l
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.I Determination of maino manaaement review for electrical comoonents Issue:
Determining if transformers, fuses, indicating lights, heat tracing, electric heaters, and recombiners are subject to an aging management review.
NRC staff oosition:
This issue relates to the guidance provided in the Statements of Consideration (SOC) in which the Commission concluded that an aging management review is required for passive, long-lived structures and components within the scope of the license renewal rule. Appendix 8 of NEI 95-10 addresses this requirement by identifying typical structure, component, and commodity groupings and a determination as to whether they require an aging management review. Several electrical components, as identified above, were not classified in Appendix B.
The rule in $54.21(a)(1), states that " structures and components subject to an aging management review shall encompass those structures and components (1)
{t] hat perform an intended function as described in 154.4, without moving parts or without a change in configuration or properties." The SOC uses the term " passive" to represent these characteristics for convenience. The description of " passive" structures and components incorporated into 154.21(a)(1 1
renewal proc)e(ss). is used only in conjunction with the IPA review in the license The SOC accompanying the renewal rule states:
"The Commission has determined that passive structures and components for which agir,g dearadation is not readily monitored are those that perform an intended function without moving parts or a change in configuration or properties." (60 FR 22477). The 50C also states: "[T]he commission has concluded that "a change in configuration or properties" should be interpreted to include "a change in state," which is a term sometimes found in the literature relating to " passive."
154.21(a)(1)(1) excludes a variety of electrical and instrumentation and control (I&C) structures and components from an aging management review for renewal such as motors, diesel generators, air compressors, pressure transmitters, pressure indicators, water level indicators, switchgear, cooling fans, transistors, batteries, breakers, relays, switches, power inverters, circuit boards, battery chargers, and power supplies. The SOC provides the following discussion as the basis for excluding several electrical and I&C devices from an aging management review: "an electrical relay can change its configuration, and a battery changes its electrolyte properties when discharging" and "a transistor can ' change its state'." The 50C also provides the following discussion as the basis to include electrical cables in an aging management review: "they perform their intended function without moving parts or without a change in configuration or properties and the effects of aging degradation for these components are not readily monitorable." (60 FR 22477)
While 554.21(a)(1)(1) excludes many electrical and I&C components from an aging management review for renewal, it also states that the exclusion is "not limited to" only these components. The staff has considered the aging Attachment w.
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.t management review requirements for transformers, fuses, indicating lights, heat tracing, electric heaters, and recombiners with respect to the definitions, background, and specific electrical examples in the license renewal rule (circuit breakers, relays, motors, circuit boards, etc.). Based on the considerable discussion provided in the rule and SOC, the staff compared the electrical components identified above with the examples explicitly provided in the rule in tems of how the performance of their intended functions would be achieved and whether aging degradation of these components would be readily monitored using currently available techniques, in a similar way by which the examples in the rule (circuit breakers, relays, switches, etc.) would be monitored. These techniques include performance or condition monitoring by testing and maintenance / surveillance programs that include instrument checks, functional tests, calibration functional tests, and response time verification tests. The results of these tests and performance monitoring programs can be analyzed and trended to provide an indication of aging degradation for these electrical components as discussed below:
Transformers perform their intended function through a change in state by stepping down voltage from a higher to a lower value, stepping up voltage to a higher value, or providing isolation to a load. Transformers perform their intended function through a change in state similar to switchgear, power supplies, battery chargers, and power inverters, which have been excluded in 554.21(a)(1)(1) from an aging management review. Any degradation of the transformer's ability to perform its intended function is readily monitorable by a change in the electrical performance of the transformer and the associated circuits. Trending electrical parameters measured during transformer surveillance and maintenance such as Doble test results, and advanced monitoring methods such as infrared thermography, and electrical circuit characterization and diagnosis provide a direct indication of the performance of the transformer. Therefore, transformers are not subject to an aging management review.
Indicating lights (dual filament) perform their intended function through a change in state by displaying readily monitorable visible light when energized with sufficient voltage.
Indicating lights perform their intended function through a change in state similar to transistors and circuit boards, which have been excluded in 554.21(a)(1)(1) from an aging management review. Any degradation of the indicating lights ability to perform its intended function is readily monitorable since the lights (e.g., control room and local panel annunciators) typically have both a visual and audio test capability that is initiated on a periodic basis by the operator. This self-test capability is relied upon to provide a direct indication of the performance of the indicating lights. Therefore, indicating lights are not subject to an aging management review.
Heat tracing performs its intended function through a change in state by supplying heat when energized, for example, to a boric acid system or a i
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refueling water storage tank / piping in order to maintain a minimum solution temperature to prevent boron from precipitating out or water from freezing in an outside pipe. Heat tracing perfoms its intended function through a change in state when energized similar to a power supply, battery charger, power inverter, etc., which have been excluded in 554.21(a)(1) the heat tracing (1) from an aging management review. Any degradation of to perform its intended function is readily monitored by alarm circuitry surveillance requ(control room and local panel annunciators) or by irements that monitor solution temperature on a periodic basis which provides a direct indication of the performance of the heat tracing. Therefore, heat tracing is not subject to an aging management review.
Electric heaters perform their intended function through a change in state by supplying heat when energized, for example, to a pressurizer water volume for reactor coolant system pressure control.
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heaters perform their intended function through a change in state similar to a battery charger, power inverter, power supply, etc., that change state when energized and which have been excluded in
$54.21(a)(1)(1) from an aging management review. Any degradation of the electric heaters' ability to perform their intended function due to aging will be readily monitorable from existing monitoring equipment (voltmeters and active perfomance of the equipment in the circuit) and surveillance requirements by verifying that the heaters are energized and by measuring circuit current on a periodic basis. Therefore, electric heaters are not subject to an aging management review for the intended function of supplying heat. The pressure boundary intended function would stil.1 be subject to an aging management review.
The staff has also considered the aging management review requirements for fuses and hydrogen recombiners as discussed below:
Fuses perform one of their two intended functions through a change in configuration or state of the fuse by interrupting power in the case of a fault or overload in a load in order to provide protection to the rest of the electrical circuit. Fuses also perfom a second intended function which is to maintain electrical continuity during non-faulted conditions. Unlike other electrical components which have simliar continuity functions such as breakers, switches, and relays which have been excluded in i 54.21 (a)(1)(1) from an aging management review, degradation of the fuse's ability to perform this intended function due to aging is not readily monitorable. Degradation of the fuse's intended continuity function may not result in detectable losses in associated
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system safety functions until degradation becomes unacceptable.
Therefore, the staff believes that fuses are subject to an aging management review.
Recombiners remove gaseous hydrogen from the containment atmosphere by combining hydrogen with oxygen to fom water. This intended function is accomplished with several component types such as electric heater w
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l' 4-banks, cabling, connections, etc. As such, recombiners should be considered as complex assemblies and should be evaluated on a plant specific basis to determine if they are subject to an aging managenent review for renewal.
Based on the above assessment, the staff concluded that these components, with the exception of fuses and recombiners, perform their intended function (s) with a change in configuration monitored and therefore, are no/ state and the effects of aging are readily t subject to an aging management review.
Electrical and I&C structures and components that are subject to an aging management review for renewal include, but may not be limited to: electrical cables and connections, fuses, electrical and I&C penetration assemblies, cable trays enclosures,,and other similar component supports.and electrical and I&C i NRC staff recommendations:
The NRC staff recommends revising Appendix B of NEI g5-10 to indicate that transformers indicating lights, heat tracing, and electric heaters do not require an ag,ing management review (recombiners should remain plant specific and to state that electrical and I&C structures and components subject to an aging management review for renewal should include: electrical cabics and connections, fuses, electrical and I&C penetration assemblies, cable trays, and electrical and I&C cabinets, panels, racks, frames, enclosures, and other similar component supports.
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r NUCl!At INit$Y IN $1lT U f f W $ $ - D ana enhoom April 10,1998 Mr. Christopher I. Grimes, Director License Renewal Project Directorate Division of Reactor Program Management U.S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Aging Management Review for Selected Electrical Components PROJECTNUMBER:g 696
Dear Mr. Grimes:
In your September 19,1997, letter to me the NRC staff provided positions on aging management review requirements for selected electrical components. We reviewed the letter and with the excepdon of the discussion on fuses, agree with the staffs positions.
The staff position on fuses is that they are subject to an aging management review because they provide an electrical continuity function, and that aging of fuses is not readily monitorible.
It is our position that electrical continuity is not an intended function and that even ifit were, aging degradation is as readily monitorible on fuses as it is on transistors and circuit boards which the rule specifically excludes from an aging management review.
On the first point regarding intended function, Table 4.1-1 in NEI 95-10 is entitled
" Typical Passive Structure and Component Intended Functions." The purpose of this table is to identify typical intended functions for long lived passive structures and components. As a result of discussions between NEI and the NRC staffwe i
specifically included the intended function," Provide insulation resistance to precludo shorts, grounds and unacceptable leakage current," to address electrical j
cables and connectors. Electrical cables and connections are the only items t
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April 10,1998 Page 2 identified in 154.21(aXIXi) that require an aging management review because they are passive" components. Electrical continuity is not included as an intended function of electrical cables and connections. Therefore, it is our view that
" electrical continuity"is not an intended function of other electrical components identified.
Regarding our position on aging of the fuses being readily monitorible, we agree fuses perform two functions. The first is interrupting power to provide protection to the electrical circuit. The second is maintaining electrical continuity during non-faulted conditions.
As your letter notes, maintaining electrical continuity during non faulted conditions is a function of all electrical components, including those listed in (54.21(aXIXi) as excluded from an aging management review. The electrical continuity function for these electrical components is demonstrated by perfortnance testing, meaning when energized the component either works or it does not work. Further, degradation of the electrical continuity function is as equally detectable in fuses as it is in transistors and circuit boards which are excluded from an aging management review.
Therefore, we do not consider electrical continuity an intended function of fuses. It is unclear why fuses are specifically being called out as requiring an aging management review. Wn would be happy to further discuss this matter with you in more detail.
Sincerely, 8
Douglas J. Walters DJW/npg 1
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