ML20045G258
| ML20045G258 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/06/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20045G235 | List: |
| References | |
| IEB-92-001, IEB-92-1, NUDOCS 9307130105 | |
| Download: ML20045G258 (3) | |
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S UNITED STATES j
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NUCLEAR REGULATORY COMMISSION g
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l WASHINGTON, D.C. 20555-0001 ENCLOSURE 1 i
i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
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REGARDING ALTERNATIVE COMPENSATORY MEASURES i
FOR CONTINUOUS FIRE WATCHES j
i NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT 1 l
i DOCKET NO. 50-245 l
1.0 INTRODUCTION
l By letter dated December 23, 1992, the Northeast Nuclear Energy Company 1
(NNECO) requested that the staff approve alternative compensatory measures for j
inoperable Thermo-Lag fire barriers in lieu of the continuous fire watches that are presently in place at Millstone Unit 1 in conformance with NRC Bulletin 92-01, Supplement 1.
NNEC0 proposed to install remote camera monitoring systems for the auxiliary boiler room (fire zone T-6), turbine building service area (fire zone T-3C), turbine building duct bank (below fire zone T-3B), and turbine building auxiliary ventilation room (fire zone T-12B).
NNECO indicated that the camera: would be directed in such a way as to detect I
the presence of a fire in the vicinity of the Thermo-Lag fire barrier installations and would be monitored continuously. NNEC0 based its request on low combustible loading, availability of fire bo" stations, and in one case, the availability of automatic suppression and det tion systems.
2.0 EVALUATION l
In response to Bulletin 92-01, Supplement 1, NNECO implemented continuous fire watches in accordance with plant technical specifications for inoperable fire barriers. The fire barriers are used to prevent a fire from damaging cabling or equipment required for safe shutdown in the event of a fire.
Nuclear power plant fire protection programs are developed from the defense-3 in-depth principles aimed at achieving an adequate balance in:
Preventing fires from starting; Detecting quickly, controlling, and extinguishing promptly those fires that occur; Protecting structures, systems, and components so that a fire that is not promptly extinguished will not prevent the safe shutdown of the plant.
9307130105 930706 PDR ADOCK 05000245 P
. 1 The defense-in-depth principle holds that strengthening any one echelon can l
compensate for weaknesses in the other echelons.
In its submittal of December 23,1993, NNEC0 requested staff approval of an l
alternative compensatory action in lieu of the continuous fire watches. NNECO
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proposed to install a remote camera monitoring system in lieu of the continuous fire watches that are presently in place.
NNECO indicated that the remote camera monitoring system would be directed in such a way as to detect the presence of a fire in the vicinity of the Thermo-Lag fire barrier
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installations and that the video system would be continuously monitored at a remote location.
NNEC0 proposed to provide the monitoring system for the auxiliary boiler room (fire zone T-6), turbine building service area (fire zone T-3C), turbine building duct bank (below fire zone T-38), and turbine building auxiliary ventilation room (fire zone T-128). NNECO indicated that the fire loading is low in all areas except fire zone T-3B where the combustible loading is negligible. Fire hose stations and extinguishers are available either within the rooms or adjacent areas.
Fire zone T-6 has automatic sprinkler and detector systems.
The purpose of the continuous fire watches is to compensate for the reduction in the fire protection echelon of defense-in-depth that is introduced by the i
t degraded or inoperable fire barriers.
l As part of the' defense-in-depth principle, a continuous fire watch enhances l
l the fire prevention echelon by recognizing and immediately reporting fire hazards such as transient combustibles introduced into the area. The fire watch can also compensate for an inoperable fire barrier in that the fire l
watch enhances the fire detection echelon by detecting the fire prior to the fire detectors activating and promptly notifying the control room of the size and nature of the fire and, upon arrival of the fire brigade, directing it to the exact location of the fire. A remote camera monitoring system cannot i
offer the same fire prevention or fire detection capabilities of a fire watch.
The fire watch may also enhance the fire suppression echelon of defense-in-depth by using a portable fire extinguisher to initiate manual fire fighting action during the incipient stage of fire growth.
The overall effect of the enhancements provided by the presence of fire watches in the affected zones adequately compensates for the weaknesses in the fire protection echelon created by the inoperable barriers. The use of a camera directed in the vicinity of the fire barrier, however, does not provide reasonable assurance that the presence of fire hazards in another part of the fire zone would be observed on the video monitor or that an incipient stage firr wbM be observed before it becomes fully developed and challenges a fire u.vrier.
In a limited number of cares, we have approved the use of camera monitoring in lieu of fire watches. Where m era monitoring was approved, it was to mitigate overriding high radiattor, and ALARA concerns for the fire watches and in some cases, to alleviate significant access problems. These conditions do not apply at Millstone Unit 1.
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3.0 CONCLUSION
1 The physical presence of fire watches in these affected areas provides i
reasonable assurance that fires will be prevented through prompt recognition and disposition of fire hazards and that a fire that occurs despite these efforts will be detected and extinguished during its incipient stage. The remote camera monitoring system proposed by NNECO will not provide-an adequate level of fire prevention, detection, or suppression capabilities, and, therefore, is not an acceptable substitution for a fire watch in the zones identified by NNECO. Moreover, the camera system is not needed to mitigate ALARA concerns. The NRC staff has concluded, therefore, that NNECO's request to utilize a remote camera monitoring system in lieu of continuous fire watches is not acceptable.
j Principal Contributor: J. Holmes Date:
July 6,1993 4
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NUCLEAR REGULATORY COMMISSION 4
f wasmorou. o c. msm June 16, 1993 ENCLOSURE 2 Docket No. 50-245 MEMOR/JDUM FOR:
File FROM:
James W. Andersen, Acting Project Manager Project Directorate I-4 Division of Reactor Projects - I/II
SUBJECT:
MILLSTONE UNIT 1 - CONFERENCE CALL TO DISCUSS VIDEO CAMERA REQUEST On June 9, 1993, the NRC staff and Northeast Nuclear Energy Company (NNECO) held a telephone conference call to discuss NNECO's request dated December 23, 1992, to install video cameras in lieu '? continuous fire watches at Millstone Unit 1.
NNECO has continuous fire wate es stationed in areas with Thermo-Lag 330 per Bulletin 92-01 guidance which states, " implement compensatory measures, such as fire watches, in accordance with plant procedures, consistent with those which would be implemented by either plant technical specifications or an operating license condition for an inoperable fire barrier."
In the December 23, 1993, letter, NNECO proposed to install cameras in the areas with Thermo-Lag, directed in such a way as to detect the presence of fire. NNECO also stated that the remote camera system would be monitored continuously. The staff has completed its review of NNECO's request and has determined that a remote camera monitoring system, in lieu of continuous fire watches, is not acceptable. The purpose of the June 9, 1993, telephone conference call was to present the bases for denying NNECO's request and to discuss possible alternatives NNECO may want to consider in lieu of the continuous watches currently employed at Millstone Unit 1.
The following major items were discussed during the conversation:
The staff stated that NNEC0's request to install video cameras in lieu of continuous fire watches was being denied.
The staff stated that nuclear power plant fire protection programs are developed using defense-in-depth principles. The defense-in-depth crinciple holds that strengthening any one echelon c&n compensate for weaknesses in the other echelons. NNFr0 argued that a remote camera monitoring system is the equivalent of a continuous fire watch. The staff does not agree. As part of the defense-in-depth principle, a continuous fire watch enhances the fire prevention echelon by recognizing and immediately reporting fire hazards such as transient combustibles introduced into the area.
The fire watch can also compensate for an inoperable fire barrier in that the fire watch enhances tne fire detection echelon by detecting the fire prior to the fire detectors activating and promptly notifying the control room of the size and nature of the fire and upon arrival of the "f%769'OM3
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File June 16, 1993 fire brigade, directing it to the exact location of the fire. A remote camera monitoring system cannot offer the same fire prevention or fire detection capabilities of a fire watch.
Therefore, NNEC0's request to i
utilize a remote camera monitoring system in lieu of continuous fire watches is not acceptable.
l The staff pointed out that in a limited number of cases, the staff has approved the use of camera monitoring in lieu of fire watches. Where camera monitoring was approved, it was mostly to mitigate overriding high radiation and ALARA concerns for the fire watches and, in some cases, to alleviate significant access problems.
The staff discussed possible alternatives to the continuous fire wr.tch prior to the restoration of the degraded fire barriers. NNECO remarked that they are participating in the NUMARC testing program and the results will not be available until the end of the year. The staff stated that a possible near term alternative to the continuous fire i
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watches, would be to use temporary detection systems in the areas with Thermo-Lag and employ an hourly roving fire watch. The staff, however, i
noted that this would require a Technical Specification (TS) change request (expedited request may be appropriate). The staff also noted that suppression or video cameras combined with a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> roving watch would not be acceptable to the staff far Millstone Unit 1.
l As an alternative to a new TS change, NNECO inquired about the ongoing i
staff review of its request to rtmove the fire protection portion of the TSs out of the TSs and place then in a Technical Requirements Manual (TRM). The staff indicated that it is awaiting two things from NNECO to saplete its review. The first being that NNECO place the Fire l
rotection portior. of the TSs into the Final Safety Analysis Report (FSAR) and, second, that NNECO supplement it's April 16, 1993, TS change i
request to include a discussion of the relationship between the FSArt and the TRM. The staff indicated that it would process the TS change request as quickly as possible following receipt of the NNEC0 supplement.
l NNECO inquired about the status of the Haddam Neck exemption request concerning Thermo-Lag. The staff stated that the exemption is currently in concurrence and as written would be denied.
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The staff noted that if the removal of the Fire Protection portion of the TSs is approved, NNECO may make changes to the approved fire protection program without prior approval of the Conmiission only if l
those changes would not adversely affect the ability to achieve and riaintain safe shutdown in the event of a fire.
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File June 16, 1993 l
1 NNECO inquired about replacing Thermo-Lag with 3M materials. 3M is currently working with NUMARC regarding qualification.
In reference to i
the NNEC0 request for examples of qualified Thermo-Lag fire barriers, the staff cited Commanche Peak. The staff cautioned that NNECO should i
carefully review any replacement materials.
NNEC0 will contact the NRC staff regarding its decisions on alternatives and need for a meeting, meanwhile, the staff plans to issue its letter and supporting safety evaluation regarding NNECO's December 23, 1992, request.
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James W. Andersen, Acting Project Manager Project Directorate I-4 Division of Reactor Projects - I/II t
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