ML20154F866
| ML20154F866 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 05/10/1988 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | PUBLIC SERVICE CO. OF COLORADO |
| Shared Package | |
| ML20154F845 | List: |
| References | |
| NUDOCS 8805240108 | |
| Download: ML20154F866 (18) | |
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UNITED STATES OF AMERICA NUCLEAR RECULATION COMMISSION In the Patter of PUBLIC SERVICE COMPANY ) Docket No. 50-267 0F COLORADO )
(Fort St. Vrain Nuclear Generating Station) )
EXEMPTION I.
Public Service Coepany of Colorado (PSC or the licensee) is the holder of Facility Operating License No. DPP-34 which authorizes the operation of the Fort St. Vrain Nuclear Generating Station (the facility) at a steady-state j power level not in excess of 842 megawatts thermal. This license provides, among other things, that the facility is subject to all rules, regulations, l and Orders of the Nuclear Regulatory Comission (the Comission or the staff) now or hereafter in effect. The facility is a high temperature gas-cooled reactor (FTCP.) located at the licensee's site in Weld County, Colorado.
II. j The 10 CFFi'50.a8, "Fire Protection," and Appendix R to 10 CFR Part 50, "Fire Protection Program for Nuclear Facilities Operating Prior to January 1,1979" 8805240108 880510 PDR ADOCK 05000267 F PDR
set forth certain fire protection features recuired to satisfy the General .
Design Criterion related to fire protection (Criterion 3, Appendix A to 10 CFR Part50).
Section III.C of Appendix R recuires fire protection for equiptrent important to post-fire shutdown. Such fire protection is achieved by various combinations of fire barriers, fire suppression systens, fire detectors, and separation of safety trains (III.G.?) or alternate post-fire chutdown equipment free of the fire area (III.G.3). The objective of this protection is to assure that one train of equipment needed for hot shutdown would be undamaged by fire, and that systens needed for cold shutdcwn could be repaired within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (III.G.1).
Section III.J of Appendix P recuires emergency lighting units with at least an 8-heur battery power supply be provided in all areas needed for operation of safe shutdown equiprent and in access and egress routes thereto.
Ili.
By letters dated November 10 and December 17, 1984, and January 17 and April 1, 1985, the licensee provided details of their fire protection program and requested approval of a number of exenptions fren the technical requirements of Sections III.G and III.J of Appendix R to 10 CFR Part 50. Additional correspondence 6fi this subject is referenced in the Comission's concurrently issued Safety Evaluation. A description of the exerptions requested and a surrary of the Comission's evaluation follow.
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Exenption Requested .
The licensee requested an exemption from III.G.2 for the Three Roon Control Complex and Diesel Generator Rooms from having 3-hcur rated fire dampers, doors, and penetration seals.
The staff's principal concern was in the event of a fire of significant magnitude, products of combustion would pass through the wall and damage redundant / alternate post-fire shutdown systens on the other side. However, the areas en both sides of these valls are protected by autenatic fire detection systems. These systems clarr' in the Control Room. The staff therefore expects that any potential fire would be detected in its incipient stage before significant flame spread or roem temperature rise occurred.
The plant fire brigac'e would then be dispatched and would put out the fire using manual fire fighting enuipment. If rapid fire spread occurred, the automatic fire suppressicn systems would actuate to control the fire and reduce ambient tenperature rise. Until this cccurred, the existing walls which surround these areas would act to confine the effects of the fire to I the area of origin. Because openings exist in the walls, the staff expects a c,uantity of smoke and het gases to pass through them and enter the adjoining locations. The smoke would be so dissipated and the hot gases cooled to the point where they would not represent a significant threat to post-fire shutdown systens outside of the fire area. On this basis, the j staff concludes"that the licensee's alternate fire protection configuration, with the proposed modifications, will achieve an acceptable level of fire safety equivalent to that provided by Section II.G.2.
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The special circur. stances of 10 CFR 50.12 apply in that application , l 1
of the regulation in the particular circumstances is not necessary to achieve i the underlying purpose of the rule. The purpose of the 3-hour barrier is ;
to protect redundant trains cf safe shutdown equiprent. However, this would be achieved as discussed above. Thus, the underlying purpose of the rule would be satisfied without installing the required 3-hour rated darrpers, dcors and peretration seals.
Exerption Recuested l
The licensee requested exemption fror III.G.3 for the Control Roce from i
having a fire detection system installed throughout this fire area.
The staff's principal concern is that because of the absence of an areawide l fire detection system, a fire could develop which would damage shutdown systems to the extent that the plant could not be safely shut down after the fire, ,
Mcwever, the Control Rocm is continuously manned and automatic smoke detectors are located in the Control Room cabinets and consoles. There is reasonable assurance that a fire would be detected and suppressed by the Control Room operators or the plant fire brigade before significant damage occurred. If a serious fire developed, the existing halon fire suppression system would be manually actuated to put out the fire or control it until the plant fire brigade arrived. If such a fire caused the loss of redundant post-fire shutdown systems, the Alternate Cooling Method is available to bring the plant to a safe shutdown condition. TheYefore, an areawide fire detection systen in the Control Roorn is 1
not necessary to provide reasonable assurance that a fire would be detected and post-fire shutdown capability maintained free of fire damage.
5 On this basis, the staff concludes that the licensee's alternate fire .
protection configuration provides ar acceptable level of fire safety equivalent to that provided by Section III.G.3.
The special circumstances of 10 CFR 50.12 apply in that application of i
the regulation in the particular circunstances is not necessary to achieve the underlying purpose of the rule. The purpose of the areawide fire detection is te minimize the potential for damaging all equipment within a fire area. Powever, this would be essentially achieved as discussed above.
I Thus, the urderlying purpose of the rule would be satisfied without installir.g areawide fire detection in the control rocm.
Exemption Requested The licensee requested exemption from III.G.2; for the Turbine Building frcr. having a fire detection system installed thrcughout this fire area.
The staff's principal concern with this exemption was that a fire of l
significant magnitude could develop and damage systems needed to safely shut down the plant. However, a fire detection system will be installed throughout every elevation of this fire area that does contain post-fire shutdown systems. If a fire shculd occur in these locations, it is expected to be detected by the system. An alarm would be transmitted automatically to the Control Reem and the fire brigade would subsequently be dispatched.
The brigade would put out the fire using manual fire fighting equipment.
If fire should break out on the operating floor or the upper elevations of the Access Control Bay, it would be discovered, af ter some time delay, by plant operators or the security force. Until the arrival of the fire brigade, there are no post-fire shutdown systems that could be damaged 1
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by fire in these locations. Therefore, an areawide fire detection system is not necessary to provide reasonable assurance that a post-fire shutdown l capability will remain free of fire damage.
Cn this basis, the staff concludes that the licensee's alternate fire !
protection configuration, with the proposed modifications, will achieve an acceptable level cf fire safety equivalent to that provided by Section III.G.2.
The special circumstances of 10 CFR 50.12 apply in that application of the l l
regulation in the particular circumstances is not necessary to achieve the '
underlying purpose of the rule. The purpose of the areawide fire detection is to minir.ize the potential for damagir.g all equipment within a fire area. !
Hovever, this v:ould be essentially achieved as discussed above. Thus, the underlying purpose of the rule would be satisfied without installing areawide l fire detection in the Turbine Building.
Exerptien Pequested The licensee requested exemption fror,III.G.? for the Access Control Bay l from having redundant post-fire shutdown systens adequately separated, and the area protected by autonatic fire detection and suppression systems. l The staff's principal concern was that because of the relative proximity of the reactor plant exhaust fans, a fire of significant magnitude would damage redundant post-fire shutdown systems to such an extent that safe
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shutdown could nbt be achieved and maintained.
However, the fire load in this location is not significant, with combustible ,
materials dispersed throughout the elevation. If a fire should occur, it would be detected by the fire detection system in its incipient stages before signifi-cant flare propagation or roen temperature rise occurred. The fire brigade would then be dispatched and would put out the fire using manual fire fighting equipment. Pending arrival of the brigade, the effects of the fire would be mitigated because the smoke and hot gases would rise up into the high ceiling area, which would tend to act as a heat sink. Also, the fan motors and related cables wculd be shielded fror, the effects of a fire by the metal fan enclosures.
Nevertheless, if a fire did result in damage to both reactor plant exhaust fans, the licensee will be able to recover from this damage by relying upcn a chiller unit and recirculation fan that is located in a separate fire area. Therefore, the absence of a fixed fire suppression system is net necessary to provide reasenable assurance that safe shutdown can be achieved and maintained.
On this basis, the staff concludes that the licensee's alternate fire l protecticn configuratien, plus the proposed modifications, will achieve an acceptable level of fire protection equivalent to that provided by Section 111.0.3.
The special circumstances of 10 CFR 50.12 apply in that application of the regulation in the particular circumstances is not necessary to achieve l l
the underlying purpose of the rule.
The purpose of the rule is to provide '
adequate protection for the redundant shutdown equiprent. However, in this case the equipment is already adequately protected, and redundant equipment
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9 exists in another fire area. Thus, the underlying purpose of the rule would .
be satisfied without requiring equipment separation ard autoratic fire detection and suppression.
Exemption Requested The licensee regt.ested exemption from III.G.P. and III.G.3 for Outside Areas-Exterier Routing and the Turbine / Reactor Building Contrer Vall from the requirerent for a 3-hcur fire barrier to separate redundant (alternate) post-fire shutdowri systems.
The staff's principal concern was that a fire of significant magnitude ray result in darage to ccaponents associated with the nomal post-fire shutdown systens and the alternate cooling method (ACM).
If a fire were to occur in the abcVe referenced outside locations, a l
potential exists for compenents associated with the ACM to be danaged.
Powever, because these areas are located outside ard away from the normal post-fire shutdown systets located within the Turbine Building, the products of cortsustion or radiant energy from such a fire should not affect the normal systems. Sroke and hot gases would tend to be dissipated in the open air. Radiant energy would be mitigated by the intervening open space and by the exterior walls of the Turbine Building. Similarly, if a fire were to occur inside the Turbine or Reactor Building, the fire should be detected I by the autcmatic fire detection syster or by plant operators or the security force.- The fire wculd either be extinguished manually by the plant fire brigade er by the automatic fire suppression systems. Because
t these locaticns are large cren plant areas, the smoke and hot gases from ,
such a fire might spread within each area. But it is the staff's judgnent that the metal and rasonry walls which bcund these fire areas are capable to a significant extent of confining the effects of the fire to the immediate fire area, until the fire is extinguished. Because these walls are not all fire-rated, scre products of combustion may spread beyond them.
Powever, the sroke ard het gases would be cooled and dissipated so that there will be tc threat to the redundant / alternate post-fire shutdown systers in the adjoining fire areas. Therefore, complete 3-hour rated fire walls are not necessary te provide reasonable assurance that safe shutdown conditiens could be achieved and maintained with undar, aged post-fire shutdown systems in the other fire areas.
On this basis, the staff concludes that the licensee's alternate fire protection configuration will achieve an acceptacle level of fire sa"ety equivalent to that achieved by cor,pliance with Sections III.G.? and Ill.G.3.
The special circunstances of 10 CFR 50.1? apply in that application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rale. The purpose of the rule is to provide adecuate protection and separation for alternate / redundant post-fire shutdown equipment. However, in this case the equipment is already adecuately separated.
Thus, the underlying purpose of the rule would be satisfied without installing 3-hour rated firs barriers.
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, Exemption Recuested .
The licensee requested exemption from III.G.? for Alternate Cooling Method /
Ccngested Cable Area Interface from having redundant post-fire shutdown systems adequately separated ar.d the area protected by automatic fire detection and suppression systens.
The staff's principal concern with the level cf fire safety in these locations was that a fire of significant magnitude might damage systems associated with both the normal post-fire shutdown capability and the alternate ccoling method. There is no major unmitigated fire ha:ard in these locations. The only significant hazard which would represent a threat to post-fire shutdown systems is the concentration of corbustible insulation on the cables. However, these cable concentration areas are protected by autccatic sprinkler systems. The suppressicq systems alcng the "G" and "J" walls were originally designed for manual actuation.
Pcwever, at the staff's request, the licensee ccnverted these systems to automhtic actuation. Additionally, the interface areas will be protected by an automatic fire detection system. As a result, any potential fire should be detected early, before significant fire propagation or room temperature rise occurs. The fire would then be extinguished by the plant fire brigade using manual fire fighting equipment. If rapid fire spread occurred, the automatic wet pipe sprinkler systems should actuate and limit
__ l fire spread, moderate room temperature rise, and protect the post-fire j shutdown cables along the "G" and "J" walls. Until the arrival of the brigade, the spatial separation between post-fire shutdown systems provides passive protection to prevent damage to redundant / alternate post-fire I
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shutdown systems. For those systems which are not sufficiently separated, the .
licensee has identified alternate means of achieving and maintaining safe shutdewn that would not be sffected by a fire.
On this basis, the staff concludes that the licensee's alternate fire protection configuration, with proposed n'odifications, will achieve an acceptable level of fire safety equivalent to that achieved by compliance with Section III.G.2.
The special circumstances of 10 CFR 50.12 apply in that application of the regulation in the particular circunstances is not necessary to achieve the underlying purpose of the rule. The purpose of the rule is to provide adequate protection for the redundant shutdown ecuipment. However, in this case, the ecuiprert is already adequately protected. Thus, the underlying purpose of the rule would be satisfied without requiring equipment separation and automatic fire detection and suppressior.
Exenption Requested The licensee requested exemption from the III.J recuirement that emergercy i light be powered by individual 8-hour batteries packs.
The staff had two concerns with the proposed emergency lighting system in these buildings. The first was that a sufficient number of lights would i not be installed so as to provide an adequate level of illumination. However, all essential valves and equipment components requiring manual operator actions, and access and egress routes thereto, will be covered by the local zone lighting plus spot beams from adiacent zones. In addition, the licensee comitted to verify the adequacy of the illumination by conducting a field l
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walkdown with plant operators to ccnfirm the adequacy of the number, locations, and positioning of the lights.
The second concern was that a fire could damage the power supply to the emergency lighting. However, the new system is designed in such a manner that fire in any cre zone would not affect the emergency lighting in adjacent zones.
Therefore, individual 8-hour batteries for each emergency light are not recessary te provide reasonable assurance that sufficient emergency lighting would te available to complete safe shutdown functions after a fire.
On this basis, the staff concludes that the licensee's alternate configuratien will achieve an acceptable level of safety equivalent to that achieved by compliance with Section III.J.
1 The special circumstance of 10 CFR 50.12 apply in that application of the l regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. The proposed emergency lightirg system provides an adequate level of illumination ar.d is adequately protected against fire damage. Thus, the underlying purpose of the rule would be satisfied w?thout installing 6-hour battery packs.
Exemption Recuested The licensee requested exemption from III.G.? for the Reactor Building from having redundant post-fire shutdovn systems adequately separated and the area protected by automatic fire detection and suppression systems.
The staff's principal concern was that a fire of significant magnitude would damage systems associated with redundant post-fire shutdown methods.
Fevever, the major fire hazards in this area are covered by an automatic
fire suppression system. Consequently, a fire involving these hazards would ,
be mitigated by the system. Remaining cerbustible materials are generally dispersed throughout the remainder of the area. As a result, a fire involvirg these raterials would be of limited magnitude and extent and characterized fritially by icw flar,e propagation and ambient temperature rise.
If a fire did occur, it would be detected early by the fire detection systems. Where no detectors have been provided above the refueling floor, no shutdown systens exist. Upon actuation of the detection systen or discovery of the fire by plant personnel, the Control Room would be notified and the fire brigade dispatched. The fire would then be either suppressed manually using portable fire fighting ecuipment, or automatically if the fire originated in the sprinkler area. Until the fire is controlled, the spatial separation between pcst-fire shutdown systems which in part extends over more than ene floor elevatico, will provide reasonable assurance that a post-fire shutdown capability will remain free of fire damage.
On this basis, the staff concludes that the licensee's alternate fire I protecticn ecnfiguration, with the cemitted modifications, will provide an acceptable level of fire safety, ecuivalent to that achieved by compliance with Section III.G.2.
The special circumstances of 10 CFR 50.12 apply in that application of the regulation in the particular circumstances is not necessary to achieve theunderlyingi56rposeoftherule. The purpose of the rule is to provide adequate protection for the redundant shutdown equipment. However, in this l l
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case, the equipment is already adecuately protected. Thus, the underlying ,
purpose of the rule would be satisfied vithout requirina ecuipr.ent separation and automatic fire detection and suppression.
Exemptien Requested The licensee requested exemption from III.G.2 for the Turbine Building free having recundant rest-fire shutdown systers adecuately separated and the area protected by autoratic fire detection and suppression systems.
The staff's principal concern was that a fire of significant maunitude would darage systems associated with redundant post-fire shutdown methods.
Powever, the major fire hazards in this area are covered by an automatic fire suppression syster, or are separated by fire walls, or both. Consequently, a fire invciving these hazards would be mitigated by the protection syster.s. ,
Remaining cerbustible materials are generally dispersed throughout the remainder of the area. As a result, a fire involving these raterials would be of limited magnitude and extent. It would be initially characterized by Icw flare prcragation and arbient temperature rise. ;
If a fire did occur, it would be detected early by the fire detection system. Where no detectors have been provided, no shutdown systems exist.
Upon actuation of the detection system or discovery of the fire by plant perser.ncl, the Control Room would be notified and the fire brigade dispatched.
The fire would then be either suppressed manually using portable fire fighting equipment, or automatically if the fire originated in a sprinkler area. Until the fire is controlled, the spatial separation between l
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post-fire shutdown systems, which in part extends over nore than one floor ,
elevation, will provide reasonable assurance that a post-fire shutdown capability will remain free of fire damage.
On this tsasis, the staff concludes that the licensee's alternate fire protection ccnfiguration with the ccmritted mcdifications will provide an acceptable level of fire safety ecuivalent to that achieved by ccmpliance with Section III.G.2.
The special circumstances of 10 CFP 50.12 apply in that application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. The purpose of the rule is to provide adequate protecticn for the redurdant shutdcwn equipment. However, in this case, the l equipment will te adequately protected. Thus, the underlying purpose of the l rule would te satisfied witnout requirine equipment separation and autoriatic fire detection and suppression.
Derption Recuested The licensee requested exemption from III.G.? for Building 10 from the 1
requirerent that structural steel which is part of a fire boundary be protected ,
to achieve a 3-hour fire barrier rating.
The staff's principal concern is that the steel wail separates two rocms which centain redundant post-fire shutdewn systeins. The rooms on both sides of this wall are equipped with an automatic fire detection system. If a fire should occur, it would be detected in its forrative stages before significant temperature rise occurs. The fire would then be put out ranually using portable fire extinguishers. If rapid fire spread occurred, the automati fire suppression system should actuate to control the fire. The system has sufficient
4 extinguishing agent for a manually initiated second discharge if the fire was ,
not ccmpletely extinguished after the first discharge. Unt " the fire is extinguished, and considering the low fire loading (equivalent to a IS-rinute duration on the ASTM E-119 time temperature curve), it is the staff's judgment that the unprotected steel wil: rerain undamaged and the integrity of the fire wall will te maintained. On this basis, the staff concludes that the licensee's fire protection configuration will provide an ecuivalent level of fire safety to that achieved by cerpliance with Section III.G.2.
The special circumstances of 10 CFR 50.12 apply in that application of the regulatien in the particular circunstances is not necessary to achieve the underlying purpose of the rule. in this case, the Icw fire loading ard the presence of manual and automatic fire suppression ec,uipment minimize the threat to the steel fire barrier. Thus, the onderlying purpose of the rule would be s:tisfied without upgrading the steel wall to a 3-hcur fire rating.
IV.
Accordingly, the Corrission has determined that, pursuant to 10 CFR 50.1?,
this exemption is authorized by' law, will rit present an undue risk to the public health and safety, and is consistent with the common defense and security. The Commissien has further determined that special circumstances, as set forth in 10 CFR 50.12(a)(2)(ii), are present justifying the exemption, narely thtt the application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. Specifics are discussed in each exemption request, but in general the underlying purpose of
the rule is to accerplish safe shutdown in the event c.' a single fire and .
raintain the plant in a safe condition. This is accomplished by assuring that sufficient undamaged equipment is available to support safe shutdown, assuming a fire within the area of concern. In the areas for which an exemption is being recuested, passive as well as active fire protection features assure that ar;y single fire will not result in the loss of safe shutdown capability.
These features include separatien distance, fire barriers, sealed penetrations, water spray er haler systems to preclude propagation, and ranual actions. The fire protection features, in conjunction with low combustible loadings, provide a hich degree of assurance that a single fire will not result in loss of post-fire shutdown capability. At this tire, - ensee has not completed all of the rnodificaticr,s upon which these exerpticrs are based. However, the licensee has in place acceptabic cerpensatory measures and is comitted to the timely corpletion of the corritted modificaticr.s.
Accordingly, the Comission hereby grants the exemptions from the ,
r requirements of 10 CFR Part 50, Appendix R as described in Section III above.
Pursuant to 10 CFR 51.32, the Comission has determined that the granting of this Exenption will have no significant impact on the environment (52 FR 36319).
The Safety Evaluation concurrently issued and related to this action and
. the above referenced submittals by the licensee are available for public 1
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inspection at the Commission's Public Docur.ent Roem,1717 H Street, N.W., ,
Washington, D.C., and at the Greely Public Library, City Complex Building, .
r Greely, Colorado.
This Exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COPMISSION l
i enn M.
.. Crutchfie . Dir or Division of Reactor Proje .s - III, !Y, V and Special Projects Office of Nuclear Reactor Regulation Dated at Reckville Ma land this 9th 1 day of flay, rf988.
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