NRC 2004-0026, Request for Exemption to 10 CFR 50, Appendix R, Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979
| ML040760070 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 03/05/2004 |
| From: | Vanmiddlesworth G Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC 2004-0026 | |
| Download: ML040760070 (10) | |
Text
N oEl Committed to Nuclear Excellenj>
Point Beach Nuclear Plant Operated by Nuclear Management Company, LLC March 5, 2004 NRC 2004-0026 10 CFR 50.12 10 CFR 50, App. R U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 License Nos. DPR-24 and DPR-27 Request For Exemption to 10 CFR 50, Appendix R In accordance with the provisions of 10 CFR 50.12, "Specific Exemptions", Nuclear Management Company, LLC (NMC) is submitting a request for permanent exemption from certain requirements of 10 CFR 50, Appendix R, "Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979." Enclosure I to this letter provides the justification for this exemption request.
The requested exemption would allow crediting of limited repairs to maintain long term (greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) hot shutdown conditions using pre-staged equipment. NMC requests approval of this exemption by October 2004.
Summary of Commitments Commitments associated with this response are provided in section 4.2 of Enclosure 1.
I declare under penalty of perjury that the foregoing is true and accurate. Executed on March 5, 2004.
Gary D. Van Middlesworth Site Vice-Rresident, Point Beach Nuclear Plant Nuclear Management Company, LLC
Enclosure:
I Justification for Exemption 6590 Nuclear Road
- Two Rivers, Wisconsin 54241 Telephone: 920.755.2321
Document Control Desk Page 2 cc:
Regional Administrator, Region 111, USNRC Project Manager, Point Beach Nuclear Plant, NRR, USNRC NRC Resident Inspector - Point Beach Nuclear Plant PSCW
ENCLOSURE I JUSTIFICATION FOR EXEMPTION POINT BEACH NUCLEAR PLANT, UNITS I AND 2 INTRODUCTION In accordance with the provisions of 10 CFR 50.12, "Specific Exemptions", Nuclear Management Company (NMC) is submitting a request for exemption from certain requirements of 10 CFR 50 Appendix R, "Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979". The requested exemption would allow crediting of limited repairs to maintain long term (greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) hot shutdown conditions using pre-staged equipment.
1.0 BACKGROUND
Appendix R of 10 CFR 50 establishes the criterion that hot shutdown be achieved and maintained using installed plant equipment, and that at least a minimum complement of the required equipment shall be maintained free of fire damage by a single fire. This criterion precludes resorting to a repair of said equipment for the purposes of maintaining hot shutdown for any period of time. The term "repair", while not defined within the regulation, is understood to include the connection of cables and hoses to provide power and flow paths.
The existing Safe Shutdown Analysis (SSA) for Point Beach credits a hard-piped nitrogen bottle bank to provide the first several hours of charging pump control air during hot shutdown. However, if the normal source of instrument air is not restored prior to depletion of this bottle bank, a dedicated air compressor is available to provide continued support for long term hot shutdown (and/or subsequent transition to cold shutdown) operation. This air compressor must be connected to a suitable power supply by means of electrical cables and to the charging pump backup control air manifolds by portable hoses. Such actions constitute a "repair" per a conservative interpretation of 10 CFR 50, Appendix R, and are not permitted without a specific exemption.
This document summarizes the technical basis and justifications for the request for an exemption from a requirement of 10 CFR 50 Appendix R G.1.a for this application (e.g.
crediting the use of limited repairs to connect the dedicated backup air compressor for charging pump control air).
2.0 PROPOSED EXEMPTIONS The exemption requested by NMC addresses a portion of 10 CFR 50, Appendix R, which sets forth the requirement that fire protection features shall be provided for Structures, Systems, and Components (SSCs) important to safe shutdown.
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Specifically, the requirement that said fire protection provisions shall limit fire damage such that one train of systems necessary to maintain hot shutdown is free of fire damage.
While the explicit requirement is keep the subject equipment free from fire damage, a constructed requirement is that no repairs, for any reason, are permitted for equipment credited in the maintaining of hot shutdown conditions. Furthermore, the interpretation of the term 'repair,' is any action that requires the installation or replacement of power supplies, cables, hoses, piping, etc. This constructive proscription is interpreted to extend even to the use of pre-staged equipment fitted with manual connection fittings that do not require tools, special processes, etc., even if that equipment has remained unaffected by the fire.
The requested exemption would allow the crediting of repair activities to connect a dedicated air compressor for maintaining long-term hot shutdown conditions.
3.0 TECHNICAL ANALYSIS
The Point Beach Chemical and Volume Control System (CVCS) is credited in the Safe Shutdown Analysis with providing sufficient makeup for Reactor Coolant System (RCS) system leakage and shrinkage. This is accomplished by the operation of one or more of the installed positive displacement charging pumps to inject borated water into the RCS.
During the transition from power operation to hot standby, sufficient inventory resides within the RCS to ensure that, even with a short term suspension of charging (to isolate damaged pumps or to prevent spurious operation), the RCS inventory will remain within the available level indication range for the pressurizer (required by 10 CFR 50, Appendix R, Part L.2.b).
However, at least minimal charging must be established within approximately the first hour to make up for continued normal Reactor Coolant Pump (RCP) seal leakage. In the late 1990s, it was recognized that RCP seal leakage may increase significantly due to suspended seal cooling and seal injection. This may require more than minimal charging capability.
The speed of the installed charging pumps is dependent upon a source of compressed air or gas. Upon a loss of gas pressure, the pump(s) will continue to run, but will drop back to minimum speed.
To ensure that full charging capability is available as soon as possible after establishing hot standby conditions, a standby high pressure nitrogen bottle bank was installed by a plant modification (MR 97-068) in 1999. This bank is valved in if needed while re-establishing charging.
The nitrogen bank is sized to provide a minimum of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of full charging capability, with an analyzed maximum capacity of over 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> (reference Calculation M-09334-420-IA.2, Revision 0). However, if instrument air has been subjected to fire damage Page 2 of 8
and is not repaired within this time period, a dedicated air compressor has been provided to fulfill the requirements.
The dedicated air compressor is located in the Turbine Hall, adjacent to the nitrogen bottle backup bank for Unit 2. This location is not susceptible to a fire (including an exposure fire) that would jeopardize the continued normal operation of the charging pumps. Therefore, the intent of the separation criteria of 10 CFR 50, Appendix R, G.2 and G.3 are met by this placement.
The compressor is sized to provide well in excess of the charging pump gas consumption requirements for a simultaneous dual-unit Appendix R shutdown and cooldown (compressor capacity of 17.4 scfm at 175 psig, with a maximum combined two-unit charging pump control system demand of 7.1 scfm; reference Temporary Modification TM 02-019).
Because the availability of power may be limited due to fire damage, the compressor and power supply cables have been sized and configured with plugs to be powered from either of two different 480V welding receptacles. This permits flexibility to cope with loss of 480 V power from any single fire, and is consistent with the intent of 10 CFR 50, Appendix R, G.2 and G.3. The power cables and connectors are dedicated and prestaged in a location not susceptible to a disabling fire (for which they are credited); their installation is proceduralized (AOP-1OA, Attachment H); and Operations personnel are trained on their installation and use.
The power cables are long enough and suitably constructed to permit connection to either of two redundant power supply locations. These locations have been previously analyzed for use in the station's safe shutdown analyses to provide power to various other coping equipment (such as temporary ventilation fans), and have been evaluated as acceptable for the loads that would be imposed. The level of flexibility so afforded exceeds what could practically be achieved using permanently installed switchgear, throw-over or transfer switches, etc., while still maintaining the necessary separation requirements of 10 CFR 50, Appendix R, G.2 and G.3.
Similarly, suitable compressor discharge hoses with quick-connect fittings are dedicated and prestaged in a nonsusceptible location (for which they are credited), with procedural direction for their installation. Operations personnel are also trained on the installation and use of these hoses. The designated connection points are on the backup nitrogen bottle manifolds.
Because the locations for the two units' backup nitrogen bottle manifolds are physically separated by an intervening Class 1 structure (the control building containing Emergency Diesel Generators, vital switchgear, the AFW pumps, the cable spreading room, the control room, etc.), installation of permanent compressed air piping from both manifolds to the air compressor would require extensive modifications. In addition, certain fires within this structure would impact any such permanently installed piping.
Therefore, the use of portable hoses that can be routed through the building well after a Page 3 of 8
fire has been completely extinguished has been determined to be a preferable approach.
Conclusion Sufficient time is available to make the necessary connections to operate the backup air compressor. The appropriate equipment for this evolution is pre-staged. This evolution is proceduralized and operators are trained on the installation and use of the connections. Therefore, this approach fully meets the intent of the requirement that no repairs be necessary to maintain hot shutdown conditions. As such, the requested exemption does pose an undue risk to the health and safety of the public.
4.0 REGULATORY ANALYSIS
4.1 No Significant Impact Determination and Environmental Evaluation In accordance with the provisions of 10 CFR 50.12, "Specific Exemptions", Nuclear Management Company (NMC) is submitting a request for an exemption from certain requirements of 10 CFR 50 "Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979". The requested exemption would permit the crediting of a limited repair in order to maintain hot shutdown conditions several hours after these conditions have initially been attained. Specifically, the repair consists of connecting power supply cables from installed welding receptacles to a pre-positioned air compressor, and connecting air hosing from the same compressor to installed backup air connections.
Permanently installed backup nitrogen bottles provide a minimum of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> post-event in which to complete the task of hooking up the air compressor and completing the necessary alignments.
NMC has evaluated the proposed exemption against the criteria in 10 CFR 51.32 and determined that the operation of PBNP in accordance with the proposed exemption presents no significant impact. The proposed limited repair will be performed with staged, dedicated equipment that is maintained solely for the purpose proposed, and there is ample time in which to implement the repair using Operations personnel that are trained for the task and always present on site. As such, the intent of the regulation to ensure the capability of reaching and maintaining alternate hot shutdown conditions without resort to extraordinary measures and without undue risk of failure is assured.
Operation of PBNP in accordance with the proposed exemption will not significantly increase the probability or consequences of accidents, no changes are being made in the types of effluents that may be released off site, and there is no significant increase in occupational or public exposure. Therefore, operation of PBNP in accordance with the proposed exemption does not result in any significant environmental radiological impacts.
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With regard to potential non-radiological impacts, the proposed action does not have a potential to affect any historic sites. It does not affect non-radiological plant effluents and has no other environmental impact. Therefore, there are no significant non-radiological environmental impacts associated with the proposed action.
Conclusion Since there are no significant radiological or non-radiological environmental impacts associated with the proposed exemption, we conclude that the proposed exemption will not have a significant effect on the quality of the human environment. Therefore, as provided in 10 CFR 51.32, an environmental impact statement need not be prepared.
4.2 Commitments The following table identifies those actions committed by NMC in this document.
Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
COMMITMENTS Due Date/Event NMC will maintain an adequate source of control air for speed control of the charging pump(s) credited with maintaining RCS inventory during all phases of alternate safe shutdown. This may be a combination of compressed gas bottles and a compressor. If a compressor is used, it will be dedicated for this purpose and maintained, along with the necessary hoses, cables, connections, etc., such that it can be installed and brought online within the time necessary to support all required inventory control functions.
Upon exemption approval 4.3 Applicable Regulatory Requirements 10 CFR 50.12(a) states that the Commission may grant exemptions from the requirements of the regulations contained in 10 CFR 50 that are:
(1) authorized by law; (2) will not present an undue risk to the public health and safety; (3) consistent with the common defense and security; and, (4) special circumstances, as listed in 10 CFR 50.12(a)(2) are present.
This exemption request meets the criteria set forth in 10 CFR 50.12, as discussed herein.
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- 1. The requested exemption is authorized by law.
10 CFR 50.12 permits limited exemptions from the requirements of 10 CFR 50 (subject to specific conditions that are addressed below) when granted by the Commission.
- 2. The requested exemption does not present an undue risk to the public health and safety.
10 CFR 50, Appendix R, G.1.a, specifies that one train of systems necessary to achieve and maintain hot shutdown condition shall be free from fire damage for any given fire. The intent is that the ability to reach and maintain hot shutdown conditions is assured without resorting to extraordinary measures requiring special equipment, personnel, or procedures that would unduly delay reactor shutdown and establishment of sustainable stable decay heat removal and RCS inventory control.
The specific requirements and performance goals of 10 CFR 50, Appendix R, L.1.b and 10 CFR 50, Appendix R, L.2.b, are that the alternative or dedicated shutdown capability provided for specific fire areas shall be able to maintain reactor coolant inventory and that the makeup function shall be capable of maintaining the reactor coolant level within the level indication in the pressurizer (for PWRs).
As discussed in the Technical Analysis portion of this request, the existing provisions for ensuring long term availability of control air for the charging pumps is comparable to a permanently installed system, and meets the intent of the regulation of ensuring continued ability to maintain hot shutdown conditions.
Considering the extended time available to make the necessary connections to operate the backup air compressor, the pre-staged equipment to do so, and the training and procedures directing the installation and use of the connections, it is concluded that the existing approach fully meets the intent of the requirement that no repairs be necessary to maintain hot shutdown conditions. Therefore, the requested exemption does pose an undue risk the health and safety of the public.
- 3. The requested exemption is consistent with the common defense and security.
The common defense and security are not endangered by this exemption request.
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- 4. Special circumstances are present which necessitate the request for an exemption to a requirement of 10 CFR 50, Appendix R. G.1.a.
Pursuant to 10 CFR 50.12(a)(2), the Commission will consider granting an exemption to the regulations of 10 CFR 50 if special circumstances are present. This exemption request meets the special circumstances described in 10 CFR 50.12(a)(2) in two respects:
(ii) Application of the regulation in the particular circumstances... is not necessary in to achieve the underlying purpose of the rule...
and (iii) Compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted, or significantly in excess of those incurred by others similarly situated...
As discussed under item (ii) above, the proposed exemption is fully consistent with the intent of the applicable sections of 10 CFR 50, Appendix R, and literal compliance (i.e., having permanently installed, hard wired / hard piped power and discharge connections for the backup air compressor) are not necessary to achieve the underlying purpose of the rules.
Moreover, owing to the intervening Class 1 structure and the multiple fire locations and effects that may occur, a fully compliant permanent installation as implied by the rules would present a considerable burden without significant improvement in safety. In particular, maintaining electrical separation and protection from the various fires that may occur, while providing reliable redundant power would be disproportionate to the benefits afforded. Similarly, routing discharge air piping over, around, or through the existing Class 1 structure (with all of the attendant considerations to prevent degradation of fire barriers, security barriers, HVAC barriers, flooding barriers, etc., during normal operations) is not practical.
Part of the undue costs that would be incurred are intrinsic to the existing design of the facility. The charging pump speed controllers do not have mechanical override capability such as is used at certain other facilities. The design, fabrication, and installation of such an override has been found to not be practical due to the speed control mechanism being entirely internal to the drive motor speed reduction boxes. Also, the positive displacement pumps cannot have their discharge flows throttled to control flow as is customary with centrifugal charging pumps.
Another alternative, maintaining a sufficient supply of high pressure nitrogen (or air or other gas) onsite and hard-piped to the backup air system to support an approximate 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> mission time has been determined to be both impractical and less safe than the existing configuration. The existing supply Page 7 of 8
is provided by a '12 pack' of 3000 psi Department of Transportation (DOT) bottles that must be maintained and changed out at periodic intervals. As with any high pressure gas tank, their presence within the power block represents an increase in risk due to the stored energy. Expanding the size of the bank would require additional space, raise the cost of maintenance, and result in a proportional increase in the high pressure gas hazard.
Substitution of a liquid nitrogen tank in lieu of the high pressure nitrogen bottles is technically feasible, but introduces both a cryogenic spill risk and an asphyxiation hazard to plant personnel. In addition, if placed outdoors to alleviate these concerns, considerable additional expense will be incurred to ensure that a suitably large evaporator is installed to ensure demand can be met during the cold winter months. During summer months, significant inventory losses can be expected from the same oversized evaporator, necessitating frequent refilling.
Based on the above considerations, NMC has determined that the most practical solution consistent with the intent of the regulations (i.e., to achieve the greatest risk reduction) is the use of a dedicated compressor with prestaged connection provisions as previously described; therefore, the requested exemption is justified.
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