B12399, Discusses Proposed Mods to 10CFR50,App R Safe Shutdown Process,Involving Use of Power Feeds to Provide Significant Improvements & Flexibility to Facility Operations in Event of Fire.Oversize Drawings Encl.Fee Paid
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HARTFORD. CONNECTICUT 0e141-0270 k L J $*,7,[".L*7,*""", (203) 665-5000 April 16,1987 Docket No. 50-336 B12399 Re: 10CFR50, Appendix R U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No. 2 Fire Protection On July 11, 1986,(1) Northeast Nuclear Energy Company (NNECO) informed the NRC of NNECO's intention to revise the Millstone Unit No. 2 Appendix R safe shutdown process. The revised approach involves a broader use of the Millstone Unit No. I power feeds to provide alternate shutdown capability for Millstone Unit No. 2. These changes are significant improvements and provide flexibility to Millstone Unit No. 2 operations in the event of a fire.
Since the July 11,1986 submittal, NNECO has reviewed its Millstone Unit No. 2 safe shutdown procedure. (A discussion of the scope and nature of this review is provided in Attachment A.) During the course of the review, it became necessary reevaluate the fire areas and zones identified in previous submittals.(t It was determined that certain areas and zones should be incorporated into larger fire areas in order to:
- 1. Eliminate from consideration those areas and zones which do not contain safe shutdown components, instruments or cables;
- 2. Minimize the number of modifications required to bring barriers into compliance with Appendix R; and
- 3. Reduce surveillance requirements by mir.imizing the number of Appendix R barriers and penetrations.
l (1) 3. F. Opeka letter to A. C. Thadani, dated July 11, 1986,
Subject:
Proposed Revisions to Appendix R Shutdown Process.
(2) Starting with the W. G. Counsil letter to D. G. Eisenhut, dated March 1,1982 and all subsequent letters on this issue.
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ADOCK 05000336 6 h d[
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r U.S. Nuclear Regulatory Commission B12399/Page 2 April 16,1987 New Appendix R fire areas were established and the corresponding fire area boundaries were identified. The new fire areas were defined based on the safe shutdown equipment they contain or the potential hazard they present to areas containing safe shutdown equipment. A listing of the new fire areas and a set of drawings showing the locations of the area boundaries are provided in Attachments B and C, respectively.
Walkdowns of the newly identified fire area boundaries were conducted to evaluate compliance with Section Ill.G of Appendix R to 10CFR Part 50. During the walkdowns, information on the construction of walls, doors and dampers was collected from existing drawings and actual field verification. Next, fire loadings were calculated for each new fire area by using the data contained in the " Millstone Unit No. 2 Fire Hazards Analysis Report." The new fire loadings were calculated by totaling the combustibles in each old fire area and zone comprising the new fire area and then dividing by the total number of square feet in the new area.
Equivalent fire severities were calculated using the new fire loadings. (The concept of equivalent fire severity is discussed in the NFPA Fire Protection Handbook,15th edition, and has been accepted by the NRC in Appendix R submittals of other nuclear power plants.) The fire area boundaries for each new fire area were evaluated against the equivalent fire severity on either side of the barriers. Where necessary, modifications were made to assure that all fire area boundaries were adequate to provide appropriate protection.
While the new fire area boundaries provide adequate protection, in some instances they are not completely sealed floor to ceiling, wall-to-wall barriers.
NNECO has discussed some of these configurations with the Staff during meetings of August 28, 1986 and February 24, 1987. During the February meeting, the Staff stated that based on its limited review and site inspections, "no significant safety issue has been identified . . . "(3) During the February 24 meeting, NNECO and the Staff agreed that NNECO would consider submitting for Staff review an analysis of these fire area boundary configurations. While no firm commitment was made as to a deadline for filing any such analysis, a March 31,1987 time frame was discussed.
After a thorough review and analysis of the new fire area boundary configurations, NNECO maintains that the boundaries are sufficient "to withstand the hazards associated with the area and, as necessary, to protect important equipment within the area from a fire outside the area" (Generic Letter 86-10, Enclosure (1), p. 2). In this regard, however, NNECO provides in Attachment E information regarding selected fire area boundary configurations (3) Inspection Report 50-245/87-03, 50-336/87-03 (2/10/87 to 3/9/87) dated March 26,1987 from E. C. Wenzinger to E. 3. Mroczka, at Enclosure, p.16.
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U.S'. Nuclear Regulatory Commission B12399/Page 3 April 16,1987 ur and requests Staff review of these configurations p(4)suant to Generic Letter 86-
- 10. (See Generic Letter 86-10 at Enclosure 1, p.2.)
The modifications noted herein supplement previously granted exemptions. To the extent that the revised analysis no longer requires modifications previously set forth in past correspondence, such modifications, whether to assure compliance with Appendix R or to assure compliance with the bases for a granted exemption, will not necessarily be completed. (See Appendix D for a listing of these modifications.)
The underlying purpose of Appendix R to 10CFR Part 50 is to provide adequate fire protection to structures, systems and components important to safe shutdown. NNECO ' maintains that the existing fire protection features and modifications discussed in Attachments D and E fully satisfy this purpose. In this regard, the Appendix R modifications identified in Attachments D and E represent an expenditure of over $8,000,000.00. This is in addition to the
$10,800,000.00 expended previously by NNECO on fire protection for Millstone Unit No. 2. This significant expenditure of resources reaffirms NNECO's continued commitment to assure fire protection safety at Millstone Unit 2.
Enclosed with this request for Staff review is a check for $150.00 in accordance
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with 10 CFR 170.12. We remain available to meet with you at your convenience to once again discuss this matter.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY E.7 in,m e, E. 3. Mroczka Senior Vice President h0 /
Yl By: W. D. Romberg " )
Vice President (4) NNECO maintains that fire area boundary configurations contained in Appendix E, pursuant to Generic Letter 86-10, do not warrant issuance of an exemption. However, should the Staff disagree, NNECO requests that the Staff review the fire area boundary configurations as requests for exemptions from Section III.G.2 of Appendix R to 10 CFR Part 50. The information provided for each configuration would fully support a finding that the proposed configuration satisfies the underlying purpose of Section III.G of Appendix R to 10CFR Part 50, i.e., are sufficient "to withstand the hazards associated with the area and, as necessary, to protect important equipment within the area from a fire outside the area" (Generic Letter 86-10, Enclosure (1), p. 2). Accordingly, the exemptions would satisfy the standards of 10CFR50.12 in that strict application of Appendix R in these particular circumstances is not necessary to achieve the underlying purpose of the rule and the exemptions will not present an undue risk to the public health and safety.
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- Ul. Nuclear Regulatory Commission B12399/Page 4 April 16,1987 cc: Dr'. T. E. Murley', Region I Administrator - .
D. H. Jaffe, NRC Project Manager, Millstone Unit No. 2 T. Rebelowski, Resident Inspector, Millstone Unit Nos. I and 2 I
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~l Docket No. 50-336 B12399 i
l Attachment A Scope of Review l
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April,1987
F Attachment A B12399/Page1 SAFE SHUTDOWN ANALYSIS The process involved a number of interrelated steps which began with a review of systems and equipment required to bring the plant to, and maintain, hot and cold shutdown. This review began by analyzing the following systems to determine which portions need to remain active, and which needed to be isolated and remain isolated to ensure plant stability:
o Reactor Coolant o Low Pressure Safety Injection and Containment Spray o Chemical and Volume Control o Main Steam o Auxiliary Feedwater o Service Water o Reactor Building Closed Cooling Water o Fire Water o Electrical Distriaution While reviewing these systems, a list was developed to identify all components and equipment which is required in at least one fire scenario.
Included with this listing were valves which must remain open or closed in the event of a fire. Component interlock requirements were identified, and instru-ments which would be needed for hot and cold shutdown were listed.
Simplified flow diagrams were prepared to show the working relationship between the required safe shutdown systems, listed components, and support systems.
These diagrams show only the required cooldown paths, pumps, and the motor operated or control valves which are required or could interfere with establishing hot or cold shutdown. These diagrams are used in conjunction with the shutdown analysis to ensure shutdown paths remain available.
In order to determine which safe shutdown components or instruments would be affected by a fire in each fire area, a detailed review was performed to locate safe shutdown components and instruments, and to determine the routing of their associated power and control cables.
At the same time, a review of fire barriers shown on the drawings was performed to determine whether the original 76 zones could be combined into fire areas or '
needed to be upgraded to comply with Appendix R, Ill.G.2 guidelines. One result of l each review has been the combination of zones in order to:
Attachment A B12399/Page 2
- 1. Minimize the number of modifications required to bring barriers into compliance with Appendix R Regulations; ,
- 2. Reduce surveillance requirements by minimizing the number of Appendix R barriers and penetrations; and
- 3. Eliminate from consideration those zones which do not contain safe shutdown components, instruments, or cables.
Af ter a review of the actual cable routings, new Appendix R Fire Areas were established and the corresponding fire boundaries were identified.
Af ter completion of the above task, and evaluation of the various shutdown scenarios, an operations information matrix was developed for each fire area.
These matrices were developed for a worst case fire in each area, i.e., a fire that disables all unprotected equipment and systems in that area, therefore complicat-ing the shutdown process. Operations matrices have been prepared for all relevant areas.
An activities matrix was developed for each fire area based on the findings of the operations information matrix. This matrix identifies the activities which must be carried out to mitigate fire damage. The activities apply either with or without offsite power. The matrices do not include activities which can be carried out in the normal fashion or are included in existing procedures (such as loss of offsite power or loss of instrument air).
Electrical Analysis The analysis consisted of three parts:
o Circuit Breaker Coordination.
o High impedance Faults.
o Associated Circuit Analysis.
Circuit Breaker Coordination was ensured by an Electrical Coordination Study to
, determine the availability of the Electrical Distribution System in the event of a
) fire which impacts components or cables supplied from a distribution panel, switchgear, MCC, etc. The results of the initial study determined and identified various areas of miscoordination. These areas of miscoordination were later reviewed to determine if there was any active impact on the safe shutdown capability of the plant as a result of the existence of these miscoordinations.
The impact of High Impedance Faults on the shutdown capability of the unit was considered. A circuit coordination study that addresses coordination across the total range of potential fault currents was performed. This study does not address the af fcct of multiple high impedance faults because of the following reasons:
- a. The potential for having multi-fire induced cable faults that would result in limited fault currents for a long period is very small. This is J
Attachment A B12399/Page 3 l due to the fact that the fire would continue to degrade the cable insulation and the fault itself would tend to further decrease the impedance, thereby resulting in higher currents.
- b. In most cases, the breaker or fuse rating is a small fraction of the bolted fault current and a multiple of 2 or 3 of the normal current. We believe that, even in a laboratory setting, the insulation failure required i to allow fault currents "below the trip point for the breaker" would be
. difficult to achieve.
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- c. The cables are contained in grounded metal raceways and are in close l proximity to conductors of opposite polarity or different phase. It is far more likely that faults will occur in this manner and rapidly grow to cause the circuit breaker to trip than for a small current to develop through damaged insulation. While the long-term existence of high impedance faults on several circuits is not impossible, the existence of more than a few (3 or 4) on a single bus is incredible.
Even though NNECO does not consider multi-high impedance faults to be a credible problem, the capability to recover from this event has been considered.
The Associated Circuits Analysis considered those cables (Safety Related, Non-l Safety Related, Class IE or Non-lE) that have physical separation less than that l required by Section Ill.G.2 nf Appendix R and are asseclated with safe shutdown j circuits in one of three ways:
l o Common bus, l
l o Spurious signals, or o Common enclosure.
To determine the interaction of associated circuits with shutdown systems, a systems approach was utilized,in which the cables associated with each component
- were identified. Types of cables analyzed were power, control, and instrument ;
cables. Spurious operation of equipment / components caused by fire-induced i failures in cables were evaluated.
1 Safety and Nonsafety buses were reviewed for those circuits which had a common power source (i.e., common bus) with shutdown equipment, to insure that the power source supply to the shutdown circuits were electrically protected.
- a. For the power sources of concern, the trip characteristics of primary and secondary electrical protection devices were reviewed to insure proper i i coordination. Any coordination problems were identified.
- b. Simultaneous high impedance faults (below the trip point for the breaker on each individual circuit) were considered for all Fire Areas. Clearing such faults on nonessential circuits is accomplished by manually clearing non-required loads and reclosing the main breaker in accordance with operating procedures.
t Attachment A
, B12399/Page 4 Where equipment / components were subject to spurious operation which would affect the capability to safely shut down, various means of isolation and/or manual actions are utilized.
- 1) -Isolation prior to a fire may be accomplished by opening of designated circuits breakers.
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- 2) Isolation of control circuits in the event of a fire may be accomplished by Transfer or Isolation switches.
- 3) in some instances, spurious signals to SOVs or AOVs are' cleared by i opening circuit breakers for most DC power in the Fire Area.
- 4) Where spurious operation has occurred, procedures are established to j defeat the maloperation of equipment; respective circuit breakers are opened and the valves manually operated.
For the Common Enclosure concern all shutdown equipment and associated cables within a fire area were identified and considered subject to fire-induced failures,
! unless otherwise justified.
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Docket No. 50-336 B12399 Attachment B Old/New Fire Area / Zone Designations April,1987
, Page 1 Millstone Unit No. 2 Comparison of New & Old Fire Area / Zone Designations For Both The Fire Hazards Analysis and Appendix R Analysis New old New Old FHA FHA Appendix R Appendix R Description Auxiliary Buildinn Spent Resin Shipping Cask Room (-)45'-6" A-1A A-1A R-1 A-13/F-1 Closed Cooling Water Pump Area (-)25-6" A-1 B A-1 B R-1 A-13/F-1 l
l Waste Tank Pump Room (-)45'-6" A-l C A-3 R-1 A-13/F-1 l
Waste Tank Room (-)45'-6" A-ID A-6 R-1 A-13/F-1 Waste Gas Decay Tank Area (-)25'-6" A-l E A-Il R-1 A-13/F-1 Waste Gas Compressor Area (-)25'-6" A-l F A-12/13 R-1 A-13/F-1 Boric Acid Pumps - Spent Fuel Pool A-lG A-14 R-1 A-12/F-1 Heat Exchangers (-)5'0" Volume Control Tank Room (-)5'-0" A-!H A-20 R-1 A-12/F-1 l
Evaporator & Tanks (-)5'-0" A-!! A-21 R-1 A-12/F-1 Evaporator & Tank (-)5'-0" A-13 A-22 R-1 A-12/F-1 LPSI Room (-)45'-6" A-3 A-3 R-6 A-15 j
HPSI Room (-)45'-6" A-4 A-4 R-1 A-13/F-1 J Coolant Tank Area (-)25'-6" A-5 A-7 R-1 A-I I /F-1 Charging Pumps (-)25'-6" A-6A A-9 R-4 A-18 l
Degasifier Area (-)25'-6" A-6B A-8 R-4 A-18 Spent Resin Tank Area (-)25'-6" A-7 A-10 R-1 A-13/F-1 I
LPSI Room (-)45'-6" A-8A A-2 R-5 A-14 l Recirculation Valve Access (-)25'-6" A-8 B A-19 R-2 A-17/F-2 I
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U*8' 2 Mllistone Unit No. 2 Comparison of New & Old Fire Area / Zone Designations For Both The Fire Hazards Analysis and Appendix R Analysis
, New Old New Old l FHA FHA Appendix R Appendix R Description l
Auxiliary Building West Piping Penetration Area (-)5'-0" A-3C A-18 R-2 A-17/F-2 West Electrical Penetration Area 14'-6" A-8 D A-25 R-2 A-17/F-2 Main Steam Safety Valve Area 36'-6" A-SE A-51 R-7 A-17/F-2 Storage Crib inr Hot Tools (-)5'-0" A-9 A-16 R-1 A-12/F-1 East Piping Penetration Area (-)5'-0" A-10A A-17 R-1 A-16/F-1 East Elevation Penetration Area 14'-6" A-10B A-26 R-1 A-16/F-1 Main Steam Safety Valve Area 36'-6" A-10C A-50 R-1 A-16/F-1 Ion Exchanger Area 14'-6" A-Il A-23 R-1 A-12/F-1 Boric Acid Batch Tank - Chemical Addition A-12 A A-24 R-1 A-2/F-1 Tank Sampic Area 14'-6" A-12B A-38 R-1 A-2/F-1 Boric Acid Boronometer 14'-6" A-12C A-39 R-1 A-2/F-1 480 Volt MCC B-61 14'-6" A-13 New R-2 A-7/F-2 Spent Fuel Pool & Cask 1.ayout Area 14'-6" A-13 A-27A R-2 A-2/F-1 Railroad Bay Area 14' 6" A-14 A A-27B R-1 A-2/F-1 Top of Fuel Pool & Fuel !!andling Area 31'-6" A-14B A-27C R-1 A-2/F-1 j Auxillary Building Filtration System 14'-6" A-14 D A-27 D R-1 A-2/F-1 Cask washdown Pit 36'-6" A-14E A-34 R-1 A-2/F-1 I
"A" Diesel Generator Room 14'-6" A-15 A-28 R-7 A-9 l "B" Diesel Generator Room 14'-6" A-16 A-29 R-8 A-10 ;
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Page 3 Millstone Unit No. 2 Comparison of New & Old Fire Area / Zone Designaticns For Both The Fire Hazards Analysis and Appendix R Analysis New Old New Old FHA FHA Appendix R Appendix R Description Auxiliary Building Solid Radwaste Drumming & Storage 14'-6" A-17 A-30 R-1 A-2/F-1 Snubber Repair Shop A-18 A-31 R-1 A-2/F-1 Maintenance Shop Area 14'-6" A-19A A-32/33 R-1 A-2/F-1 Electrical Maintenance Area 36'-6" A-19B A-45 R-1 A-2/F-1 21 DC Equipment Room 14'-6" A-20 A-35 R-9 A-5 Z2 DC Equipment Room 14'-6" A-21 A-36 R-10 A-6 Z1 Battery Room 14'-6" A-22 A-41 R-9 A-5 Z2 Battery Room 14'-6" A-23 A-37 R-10 A-6 Cable Vault (Spreading Room) 25'-6" A-24 A-40 R-1 A-4/F-1 Control Room 36'-6" A-25 A-42 R-1 A-1/F-1 Computer Room 36'-6" A-26 A-43 R-1 A-1/F-1 New Computer Room 36'-6" A-27 A-44 R-1 A-8/F-1 22 East 480 Volt Load Center 36'-6" A-28 A-15 R-i l A-3 Production Test Shop 36'-6" A-29 A-46 R-1 A-2/F-1 "B" D/G Oil Day Tank Room 36'6" A-30 A-47 R-8 A-10 "A" D/G Oil Day Tank Room 36'-6" A-31 A-48 R-7 A-9 Air Handling Units 36'-6" A-32 A-49 R-1 A-2/F-1 Ventilation Equipment Room 36'-6" A-33 A-32 R-1 A-2/F-1
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Page 4 Millstone Unit No. 2 Comparison of New & Old Fire Area / Zone Designations l
For Both The Fire Hazards Analysis and Appendix R Analysis New Old New Old FHA FHA Appendix R Appendix R Description ,
Turbine Building 14'-6" Elevation General Area T-1A T-10 R-3 T-1/F-3 H2Seal Oil Unit (14'-6") T-1B T-1 R-3 T-1/F-3 31'-6" Elevation General Area T-lC T-II' R-3 T-1/F-3 DC Switchgear Room (31'-6") T-ID T-3 R-3 T-1/F-3 Turbine Auxiliary Battery Room (31'-6") T-lE New R-3 T-1/F-3 ,
54'-6" Elevation General Area T-lF T-12 R-3 T-1/F-3 Lube Oil Room (14'-6") T-2 T-2 R-3 T-1/F-3 Motor Driven AFW Room (l'-6") T-3 T-9 R-3 T-5A/F-3 Turbine Driven AFW Room (l'-6") T-4 T-9 R-12 T-5B Instrument Parts & Storage Room (25'-6") T-5 T-13 R-3 T-1 Z1 West 480 Volt Load Center Room (36'-6") T-6 T-4 R-13 T-2 Z16.9 & 4.16 KV Switchgear Room (31'-6") T-7 T-7 R-14 T-4 Cable Vault (45'-0") West T-8 T-5 R-2 T-3/F-2 Cable Vault (45'-0") East T-9 T R-15 T-4 22 6.9 & 4.16 KY Switchgear Room (54'-6") T-10 T-8 R-2 T-3/F-2 Other Buildings Containment C-1 C-5 R-15 C-1 C-1 C-1 R-15 C-1 C-1 C-2 R-15 C-1 C-1 C-3 R-15 C-1
. C-1 C-4 R-15 C-1 1
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- Millstone Unit No. 2 Comparison of New & Old Fire Area / Zone Designations For Both The Fire Hazards Analysis and Appendix R Analysis i New Old New. Old
, FHA FHA Appendix R Appendix R Description
' Other Buildings i
Intake Structure I-l I-I R-16 I-l
.i l Fire Pump House FP-2 FP-2 R-17 FP-2 l
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Docket No. 50-336 B12399 Attachment C Fire Area Drawings i
April,1987
Docket No. 50-336 B12399 Attachment D Modifications April,1987
4 MTu-N UNIT 50. 2 ,Page 1 CODE %IANCE STATUS WITH APPENDII R FIRE CHANGES TO AREA / ~ APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE
- (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE 1
A-1A No Spare parts (equipment-cabling) None Complete 1/15/87:
- will be stored on site to support necessary repairs that may be re-quired to achieve cold shutdown.
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Repair procedures will be developed None Complete 1/15/87 i to assure that cables needed to '
achieve cold shutdown will be repaired promptly. i A-1B Yes Provide-a 1-hour fire-rated enclo- Now using 3-hour Completed .1988 RO sure for charging pump cables as protection and some early shown on drawing 34022 (Charging rerouting of 22 train Pump Train B and B-swing). to outside fire area.'-
l l Stock spare parts (connectors- None Complete 1/15/87 j C cabling) required to support post-fire repairs to cold shutdown equipment within a reasonable time.
l Develop repair procedures to assure None Complete 1/15/87
- that cables needed for cold shut- !
] down will be-repaired promptly and within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, as required by Appendix R.
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i MILLSTONE UNIT NO. 2 Page 2 l
l COMPLIANCE STATUS WITH APPENDIX R 1
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FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE j (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE A radiant energy shield consisting Changing to replace Complete 1/15/87 of marinite board will be erected pump motor. Spare Motor around RBCCW pump and Motor A. on-site.
Wet pipe sprinkler system to form Write repair procedures Complete, 1/15/87 water curtain between LPSI pump cable approved &
trays and installation of early available warning ionization detectors.
A-2 No None.
A-3 No None.
A-4 No None.
A-5 No Spare parts (connectors-cabling) None Complete 1/15/87 will be stocked on site to support repair of cables needed for cold shutdown.
Repair procedures will be developed to assure that cables needed for None Complete 1/15/87 cold shutdown can be temporarily repaired.
A-7 No None.
A-8 No None.
t A-9 Yes Provide a fire rated enclosure to A three-hour wrap Complete 1/15/87 i
charging pump cables Train A and B. is provided on all three l trains.
MILLSTOME UNIT NO. 2 Page 3 COMPLIANCE STATUS WITH APPENDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (New FHA) EIEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE Install a curb / dike at front of None Complete 1/15/87 each charging cubicle.
A .14 Yes Charging Pu=p B and B (swing) ca- The B (swing) Completed 1988 R0
/ bles which run parallel to the die- power cables have been early.
sel B Cables in this area will be rerouted outside this area.
rerouted outside the fire area.
The vertical run (from ceiling to floor) of charging pump B and B (swing) cables re=aining in the area will be enclosed in a one-hour fire barrier. A marinite board radiant energy shield will also be installed around this cable run.
Stock spare parts (connectors-cabling) None Complete 1/15/87 required to support post-fire repairs to cold shutdown equip =ent within a reasonable time.
Develop repair procedures to assure that None Co=plete 1/15/87 cables needed for cold shutdown will be repaired promptly.
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l MTT I-6 UKIT NO. 2 Page 4 COffLIANCE STATUS WITH APPENDII R l
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FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE l (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE i A-15 No spare parts (equip =ent-cabling) None Co=plete 1/15/87 l will be stored on site to support l necessary repairs that =ay be re-l quired to achieve cold shutdown.
Repair procedures will be developed None Co=plete to assure that cables / equipment needed for cold shutdown will be repaired.
A-19 No None.
A-24 Yes Reroute Diesel B cables which run Not required. MP1 to N/A N/A along the hallway in close proxim- MP2 backfeed eliminates ity to Diesel A cables outside this the diesel power cables fire area, as safe shutdown equipment for this area.
Install a water curtain in the west Barrier installed Complete 1/15/87 end of fire area A-24 to segregate as a water spray on remaining Train B cables and motor environ = ental enclosure control center from Train A cables. for MCCB61.
Enclose Train B cables which pass Rerouting Train B Completed 1988 RO through the water curtain in a one- cables or wrapping early hour barrier. in three-hour fire protection.
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j NTIL M UNIT E0. 2 Page 5 C(Bef.TaufM STATES WITE APP M IX R FIRE CHANGES TO l AREA / APRIL 15, 1986 l ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE i (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE l Stock spare parts (connectors- None Complete 1/15/87 cabling) required to support post-fire repairs to cold shutdown
, equipment within a reasonable
! time.
l Develop repair procedures to None Complete 1/15/87
( assure that cables needed for cold shutdown will be repaired promptly.
l A-25 No None.
A-26 No - None.
A-27D - No None.
A-28 No None.
l A-29 No None.
A-35 No None.
A-36 No None.
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l MTLI-M UNIT NO. 2 Page 6 CODFLIANCE STATUS WITH APPEEDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (New FHA) EXEMPTION PROPOSED MODIFICATIONS- MODIFICATIONS STATUS DATE-A-37 No None.
A-40 Yes Fxtend automatic wet-piped Not required for N/A N/A uprinkler system to include diesel Appendix R. MP1/M2 power cables Train A. backfeed, Fire Shutdown Panels, and fire protection of selected cables eliminate this j need.
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Provide passive, one-hour fire No longer required. N/A N/A barriers between redundant cables MP1/M2 backfeed, Fire at the crossover points. Shutdown Panels, and l fire protection of l selected cables eliminate this need.
Develop and implement customized No longer required. N/A N/A' l
administrative controls to MP1/MP2 backfeed, Fire effectively restrict the Shutdown Panels, and introduction of flammable fire protection of materials including-liquids in the selected cables cable vault. eliminate this need.
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MILLSTONE UNIT NO. 2 Paga 7 COMPLIANCE STATUS WITH APPENDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE A-41 No None.
A-42 Yes Customized administrative controls None Complete 5/15/86 (similar to those accepted for Haddam Neck) will be implemented to minimize introduction of flammable materials in the control room.
Normal operating procedures will None Complete 5/15/86 be revised to require an inspection each shift in the control room for flammable materials.
A transfer scheme utilizing a Hand switches are Completed 1988 R0 Wiedmuller Test Block (or provided for control early equivalent) to isolate required circuits on fire instrumentation from the control shutdown panel.
room and redirect the Instrumentation has instrumentation signals to the new Spec 20 isolators built remote Fire Shutdown Panel will be in.
installed.
Disconnecting devices for Changed location to Completed 1988 RO pressurizer PORVs, main steam be in fire area A-15 early isolation valves, atmospheric dump (i.e., West 480V valves, and SG blowdown valve Switchgear Room control circuitry will be installed directly outside to assure closure of these valves Control Room door).
during a control room fire.
MILLSTONE UNIT NO. 2 Page 8 COMPLIANCE STATUS WITH APPENDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (N;w FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE The MP1/MP2 4kV cross-feed bus will Nono To be com- 1988 RO be modified to facilitate the pleted as a alignment of Unit No. 1 emergency -
Unit 1 l
AC power to the Unit No. 2 project by emergency buses.
~
end of next Unit outage.
Manual / air operated valves to provide RCS level and pressure Change to add handwheel Open ' 198_8 RO control for cold shutdown will be to CH-192 and SI-657 ,
l' installed in charging and auxiliary ,
spray flow paths. CH-517, 518, & 519 .. Completed
[
[ early The pressurizer and reactor head Changed to proced- Approved 1988 RO vent control. circuits will be dure to open do breaker & available
! modified to protect against hot shorts for control room fires.
These modifications include removing the fuses to the control circuits during plant operation, separately fuse the-indication l portion of,the circuit"so that
! valve indicators will not be lost e
when the fuses associated with the solenoid valves are removed and ,
y insure the switchboard was
!. associated;with the colenoid valves,
~
l are not susceptible'to hot shorts.
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MILLSTONE UNIT NO. 2 Page'9 COMPLIANCE STATUS WITH APPENDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE. PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE A remote Fire Shutdown Panel in None Completed 1988 RO Fire Zone T8 will be-installed. early Procedures to assure the following None Approved 1988 RO will be developed: & available o capability to achieve safe shutdown with the loss of equipment in any one of the two fire zones.
o Spurious operation of affected equipment can be compensated for using alternate systems and manual action.
o Actions being taken outside the control room are achievable considering a fire in the-control room, time needed to accomplish the function and manpower required.
MILLSTOllE UNIT NO. 2 Page 10 COMPLIANCE STATUS WITH APPENDIX R 2
FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (N5w FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE T-4 No Will incorporate an electrical The Shutdown Fire Panel Completed 1988 RO isolation co-J,rol transfer-scheme does this by isolating early in required control circuits. both the Control Room and C-21 circuits.
T-5 No None.
T-6 No None.
T-7 No None.
T-8 No None.
T-9 Yes None.
T-10 No Provide a fire-rated enclosure for ' Service water Completed, 1/15/87 service water cables (Z-1). pumps / cables only approved &
required for cold available shutdown. Repair procedures used as needed.
Provide a fire-rated enclosure for Service water Completed, 1/15/87 l service water cables (Z-5). pumps / cables only approved &
required for cold available shutdown. Repair procedures used as needed.
MILLSTONE UNIT NO. 2 Page 11 COMPLIANCE STATUS WITH APPENDIX R l FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (N';w FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE I-1 Yes Enclose / wrap all cabling' conduit Service water Completed, 1/15/87 l associated with service water pump pumps / cables only approved &
Train A with a one-hour rated fire required for cold available.
barrier. shutdown. Repair procedures used as needed.
Provide dike / curbing around Service Service water Completed, 1/15/87 Water Pump A. pumps / cables only approved &
required for cold available.
shutdown. Repair procedures used as needed.
Install an automatic water curtain Service water Completed, 1/15/87 spray system around Service Water pumps / cables only approved &
Pump A. required for cold available.
shutdown. Repair procedures used as needed.
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! l MILLSTONE UNIT NO. 2 Page 12 COMPLIANCE STATUS WITH APPENDIX R FIRE CHANGES TO AREA / APRIL 15, 1986 ZONE PREVIOUS APRIL 15, 1986 SER SER PROPOSED DUE (New FHA) EXEMPTION PROPOSED MODIFICATIONS MODIFICATIONS STATUS DATE C-1 No A radiant energy shield will be Tray covers, conduit Completed 1988 RO thru installed between redundant reroute and fire stops early C-6 pressurizer instrumentation cables. added instead.
m.LMu'a-_--wamaa-- 2..-.._.m -
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Docket No. 50-336 B12399 Attachment E Selected Fire Area Boundary Configurations i
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I April,1987 i l
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B12399/ Attachment E Page1 1.0 Water Curtains 1.0 Staff Review Requested Pursuant to Generic Letter 86-10 (Enclosure 1, p. 2), Staff review of the fire area boundary between Areas R-1 and R-4 is requested. For this boundary (entrance to the Charging Pump Cubicles), NNECO has installed a water curtain in lieu of physical barriers.
1.2 Discussion Due to the location of equipment and the need to maintain access / egress routes for personnel and equipment, it is not practical to install a physical barrier in the walkway between fire areas R-1 and R-4 (See Attachment 2). Accordingly, in this walkway, NNECO has installed a closed head, closely spaced heat activated " water curtain" as the fire barrier. The " water curtain" is similar in design to the water curtains approved at our Haddam Neck Plant (see Attachment I for typical details). It should be noted that the Staff, af ter a complete plant walkdown had previously approved this configuration without any additional protection such as the water curtain which NNECO has now installed (See SER Supplement dated April 15,1986 at page 14).
The (-) 25'-6" elevation of the Auxiliary Building contains 3 redundant charging
, pumps and other plant cables and equipment. To separate the charging pump i cubicles from other areas within the (-)25'-6" elevation, NNECO has installed a
" water curtain" as the fire barrier. This water curtain was erected, in lieu of a i
physical completely sealed barrier, based upon the following:
o Cable trays run in area which would obstruct barrier o Personnel access must be maintained o Equipment access must be maintained l NOTE: Charging pump separation was addressed in a previously approved exemption.
, The water curtain is designed to detect a fire and spray water across the ,
opening / passageway. In addition, sprinklers are installed in/above the trays, I which pass through the water barrier. This design assures that a fire would l be stopped at the water curtain (see Attachment 2). l 1.2.2 Fire Protection Features The (-)25'-6" elevation has early warning ' smoke detection and manual firefighting capabilities in the form of hose stations and portable fire extinguishers. Fire brigade response would be rapid. Combustible loading ** ,
for each area is as follows: i l
l
B12399/ Attachment E E
Page 2 I
Loading Duration Area (BTUs) (Mins.)
Charging Pump Cubicle: 39,427. 30 Area Outside Charging Pumps: 29,170 22
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1.3 Conclusion NNECO has evaluated the areas discussed above and has concluded that erection of a completely sealed concrete barrier (or fire door) would not be practical. The installation of a water curtain would not impede day to day plant operations and i
provides adequate fire protection separation to the entrance.to the charging pump cubicles. The water curtain at the (-)25'-6" elevation assures that a' fire that starts in the general area would not propagate through the labyrinth entrance to the charging pump cubicle. NNECO maintains that this fire area boundary configuration provides adequate protection of necessary equipment in view of the equipment location and minimal fire loading.
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B12399/ Attachment E Page 3 2.0 Fire Dampers 2.1- Staff Review Requested a
Pursuant to Generic Letter 86-10 (Enclosure 1, p. 2), Staff review of the fire area boundary between areas R-5 (LPSI Pump A Room) and R-6 (LPSI Pump B Room) is.
requested. Specifically, the review is requested for 2 duct openings with no dampers.
2.2 Discussion i
Specific characteristics of each duct opening are listed in the following table and j discussed below:
- Combustible !
Duct Opening Elevation Detection Loading R-5/R-6 (-)t4 5'-6" Yes 7 mins /10 mins 1
i R-5/R-6 (-)f>5'-6" Yes 7 mins /10 mins
- 2 i Duct openings (R-5/R-6) 1 and (R-5/R-6) 2 connect LPSI' Pump A Room and LPSI-Pump B Room (see Attachment 1). The fire severity in R-5 is less-than 7 minutes.-
The fire severity in R-6 is less than 10 minutes. These fire loadings represent full cable tray loading and a complete change out of oil (change out of oil represents a transient combustible which normally occurs when the plant is in safe shutdown).
The equipment in each room is redundant; however, it is only required for ' cold shutdown. Smoke detection is installed in each area and a hose station is installed at the entrance to the LPSI Rooms. Each area is a high radiation area with locked doors (precludes additional transients). It should be noted that the major redundant '
equipment pumps are located near the floor and are not sensitive to smoke. - In addition, materials and general procedures (utilized for other areas) exist for 3 replacing LPSI cables, should it be required. The fire loadings associated with each l room are very low and would not generate enough heat to affect components in the ;
adjacent area. In addition, the sheet metal ducts (20 gauge) which pass in these i openings (25" X 19" and 18" X 12") provide physical separation (NFPA 90A allows up to a 1-hour rating for sheet metal ducts with no dampers). -
2.3 Conclusion Combinations of limited fire loading, sheet metal ducts and installed detection assures that a fire which originates in either areas (R-5 or R-6) - would not breach the existing fire barrier between the fire areas or cause damage to redundant safe
, shutdown equipment. Based upon the above, it is NNECO's position that the fire area boundaries' with the ducts are clearly adequate to withstand the associated fire hazard and provides reasonable assurance : of protection - of redundant equipment in the two' areas.
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B12399/ Attachment E Page 4 3.0 Fire Barrier With Negligible Loading 3.1 Staff Review Requested Pursuant to Generic Letter 86-10 (Enclosure 1, p. 2), Staff review of the fire area boundary between areas R-1 and R-2 is requested. In particular, this request refers to the opening between the east and west Main Steam Isolation Valve (MSIV) Rooms which are located in Appendix R fire areas R-1 and R-2, respectively.
3.2 General Description of Areas The MSIV Rooms are located on the 36'-6" elevation of the Auxiliary Buildings adjacent to the Containment Structure. The east MSIV Room is part of Appendix R fire area R-1. This fire area also contains the east Electrical Penetration Room and the east Mechanical Penetration Room which are located on successive lower elevations. Fire area R-1 also includes most of the general areas of the Auxiliary Building. The west MSIV Room is part of Appendix R fire area R-2. This fire area also contains the west electrical and mechanical penetration areas.
This request for review involves an opening between the east and west MSIV Rooms at their common wall. At this point, both rooms have narrowed to a width of approximately 8' (See Figures 1 and 2). There is no wall at this location from a point 6' above the floor to the ceiling (located at approximately elevation 160').
Only pipes are routed through this opening. There are no intervening combustibles passing through this opening. Indeed, as noted below, the east and west MSIV rooms have only I and 2 minutes fire loading respectively. As stated in the Fire Hazards Analysis submitted to the NRC in 1977 (as recognized by the subsequent Safety Evaluation Report issued in 1978), neither of the MSIV Rooms have fire detection or suppression systems. It should be noted that af ter extensive review and site inspections, the NRC Staff found the barrier configuration acceptable in its SER dated September 19,1973 at p. 5-7 thru 5-9.
3.3 Analysis 3.3.1 Area Description The MSIV Rooms are located on the 36'-6" elevation of the Auxiliary Building where it adjoins the south wall of the Containment Building as shown on the attached drawing. The floor of each MSIV Room is concrete, supported by steel, and is located over their respective (east and west) electrical penetration areas. There are minor openings in the floor between the respective MSiV Rooms and their associated Electrical Penetration Rooms and, as such, they are in the same respective fire areas (east penetration area
- fire area R-1, and west penetration area --fire area R-2). The ceiling of the MSIV Rooms is located at elevation 160', which is the roof of the Containment Enclosure Building.
l
B12399/ Attachment E Page 5 The combustible loading in the two MSIV Rooms are as follows:
East MSIV Room 1 minute West MSIV Room 2 minutes 3.3.2 Fire Protection Systems As described above, detection and suppression systems are not installed in either of J the MSIV Rooms. However, portable fire extinguishers are provided in each MSIV Room. Hose stations for manual fire fighting are located in the spent fuel pool -
operating area, adjacent to the MSIV Rooms. Fire detection is provided in both the east and west Electrical Penetration Rooms located directly below the MSIV Rooms.
3.3.3 Safe Shutdown Components Table I contains a listing of the valves located in the east and west penetration rooms.
3.3.4 Fire Hazards Analysis There are a number of factors in the MSIV Room that will mitigate the effects of a fire. These factors are discussed in detail below:
- o There are no combustibles passing through the opening between the two MSIV Rooms that could cause the spread of fire from one room to the other. A minimum of 20 feet free of intervening combustibles is maintained.
o The fire load in both rooms is very low (2 minutes and under). Therefore, not only is a fire less likely to occur, if one does ignite, the intensity and heat output will be low, theoretically less than 5000F A fire of this size does not pose a flashover threat especially in an area this large. (Flashover is generally defined as the point where a fire spreads beyond the room or area of origin.)
o Due to the high ceiling height in the MSIV Rooms (over 100'), detection and suppression would have little, if any, effect. Smoke would stratify below the ceiling before reaching smoke detectors which are normally installed on the j ceiling. Automatic sprinklers (which constitute the standard method of 1 protection in this type of room) would have a delayed opening time due to the ceiling height and the discharge pattern would be ineffective after a 100' drop. Therefore, detection and suppression systems would not appreciably enhance the fire protection in the MSIV areas.
o Since there are openings between the east and west Electrical Penetration )j Rooms and their respective MSIV Rooms, there is a potential for fire spread between the two elevations. While a fire can spread vertically, the same features described above will prevent the fire from spreading horizontally to the adjacent MSIV Room. For enmple, a fire originating in the east Electrical Penetration Room may spread upward to the east MSIV Room (they are both within the same fire area). However, due to the lack of 1
a l- B12399/ Attachment E 4 Page 6-intervening combustibles and the high ceilings, the fire .will not propagate into the west MSIV Room. Therefore, the west Electrical Penetration Room would not be threatened.
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j o There are no safe shutdown components located near the opening.
3.4 ' pciciusion NNECO maintains that the lack of a full barrier between fire areas R-1 and R ;
. does not adversely impact the ability to protect safe shutdown components in the event of a fire. The technical bases that justify this conclusion can be summarized '
as follows:
].
o There are no intervening combustibles that pass through the opening between
- the two MSIV Rooms. A distance of at least 20 feet free of intervenin'g.
{ combustibles is maintained, i
j o The fire load in the two MSIV Rooms is 2 minutes or less.
1 o The ceiling height (over 100') will permit heat and smoke to rise vertically,-
] not horizontally, through the opening, eliminating exposure to the other MSIV i Room. An inspection of the MSIV rooms by the NRC on February 26,-1987, i
verified that the MSIV rooms do not contain combustibles that could -
! contribute to fire in adjacent areas and that the ceiling heights and prevailing air flow appeared to confirm that heat and smoke, if generated in- these areas, would rise vertically eliminating exposure to the adjacent MSIV room..
. (Routine Inspection 50-245/87-03; 50-336/87-03, dated March 26,1987, at 4 page 17).
J j o There are no safe shutdown components located near the opening.
) Therefore,it is NNECO's position that the boundaries separating fire areas R-1 and 1 R-2 are adequate to protect the redundant safe shutdown equipment in the event of
] a fire. In this regard, based on substantial analysis by NNECO (as confirmed by 1 previous inspections of the Staff), the fire area boundaries will withstand the l l hazards associated with the fire areas and, as such, are acceptable pursuant to-
- Generic Letter 86-10, Enclosure I at p.2.
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Page 1, Normal Required Equipment ID Position Position Required For Condition Condition Control Logic Notes S.G. MSIV ADV 2-MS-64A Hot Open Closed Open:
(HV-4217) (Isolation) Manual Close: Manual,(override Loss of Air, auto MNclose)
Steam Isolation Sig.
2-MS-64B Hot Open Closed Same as 2-MS-64A (HV-4221) (Isolation)
S.G. MSIV Bypass MOV 2-MS-65A Hot Closed (HV-4218) Closed Open:
(Isolation) Close: Manual Manual, (override auto close)
MN Steam Isolation Sig. Power Removed, O to 100%
position indicator 2-MS-65B Hot Closed (HV-4222) Closed Same as 2-MS-65A (Isolation)
Atmospheric Steam Dump ADV 2-MS-190A Hot / Cold Closed (PV-4223) Closed / Open: Manual w/ Handwheel, Turbine Modulation Trip (w/ Selector S. " quick open" Perm.)' Positioner Close: Manual, Loss of Air Modulates on Main Steam Pressure via either remote (C05) or local controller (C21) 2-MS-190B Hot / Cold Closed (PV-4224) Closed / Same as 2-MS-190A Modulation
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Auxiliary Feedwater Turbine Steam Stop MOV 2-MS-201 Hot Open Open Open/Close:
(HV-4191) Manual (Remote and Local) 2-MS-202 Hot Open Open Same as 2-MS-201 (HV-4189) i
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B12399/ Attachment E Page 7 4.0 FIRE ~ AREA BOUNDARIES BETWEEN FIRE AREAS R-3 AND R-12 4.1 STAFF REVIEW REOUESTED
~
Pursuant to Generic Letter 86-10 (Enclosure 1, p.' 2), Staff review of the fire area boundary between Area R-3 and R-12 is requested. In'particular, this request refers to unsealed openings in the Turbine -Driven Auxiliary Feedwater Pump (TDAFW) _ Room barriers. However, these unsealed openings do not jeopardize the adequacy of the existing barriers to prevent a fire from entering the TDAFW Room'.
< 4.2 GENERAL DESCRIPTION OF AREAS
- The TDAFW Pump Room is located on'the O'-0" elevation of the Turbine t Building adjacent to the Motor Driven Auxiliary Feedwater (MDAFW) Pump Room.' Both rooms are located below the ground floor (14'-6" elevation) of
, the Turbine Building. -Either the TDAFW pump or the MDAFW pumps can i provide auxiliary feedwater and, therefore, the rooms are redundant to one
- . another. There_ are several unsealed openings between the TDAFW and the 1
MDAFW, as w' ell as between the TDAFW Room and the turbine floor.- '
These openings, due to several factors which will b'e described in detail in the analysis below, do not prevent the barriers from providing adequate i fire separation for the TDAFW Room.
I-4.3 ANALYSIS
- 4.3.1 Area Description i . .
The TDAFW and the MDAFW Pump' Rooms are located side by side on-elevation O'-0" of the Turbine Building. Both rooms are located below
. the 14'-6" elevation of _ the Turbine Building, which is the ground -
floor. The TDAFW Room is Appendix R Fire Area R-12. lBoth the-
! MDAFW Pump Room and the Turbine Building general area are parte of Appendix R. Fire Area R-3. Reinforced concrete walls and floors, with an inherent fire resistance, separate the TDAFW Room from the other area. There are, however, openings into the .TDAFW Pump -
Room from both the MDAFW Pump Room and the Turbine Building ground floor. These openings include:
- A nonfire rated watertight door between the' MDAFW and the '
- TDAFW Rooms. An exemption request concerning this door .was_- 1 submitted to the NRC' in a letter dated March 1,1982 and subsequently granted.
Several pipe and conduit penetrations between the MDAFW and- .
[ TDAFW Rooms. The penetrations are not sealed, j 1-
[ -
Several pipe penetrations between the Turbine Building and the .
TDAFW Room. These are also unsealed.
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- B12399/ Attachment E Page 3
- A' 5' x 11' hatch through the Turbine Building floor to the TDAFW Room. This hatch has a concrete plug and is sealed in place with a nonporous sealant.
! The piping penetrations are sleeved core bores, with the piping 1 passing through the center. The overall size of the penetration varies -
from 6" to 20" in diameter (with slightly smaller pipes inside).
Two penetrations have grate covers with no pipes installed.
i The equivalent fire severities based on the combustible loading in
~
i each area is given below. These figures are taken from the 1986.
4 revision of the Millstone Unit 2 Fire Hazard Analysis (FHA):
o turbine driven auxiliary' feedwater pump room - 2 minutes o motor driven auxiliary feedwater pump room - 1 minute o turbine building 14' - 6" elev.~ general area - 30 minutes 4.3.2 Safe Shutdown Components I
The TDAFW Pump Room obviously contains the Turbine Driven i' (Terry Turbine) Auxiliary Feedwater pump. This pump 'is used for Auxiliary Feedwater when the loss of offsite power, or a scenario, causes the loss of the Motor Driven Feedwater pumps. The TDAFW pump can be started either manually or remotely via protected (by a three-hour rated fire wrap) cables.
The MDAFW Pump Room contains two Motor Driven Auxiliary Feedwater pumps. These can also be started either remotely or e manually.
The flow control valves for both the Turbine and Motor Driven pumps are located on the 14'-6" elevation of the Turbine Building in the area directly above the pumps. These valves fail open which is the correct .
position so they are unaffected by a fire.
4.3.3 Fire Protection Systems The TD & MD AFW Pump Rooms have fire extinguishers _within each room. Automatic _ sprinklers are provided over the cable trays that "
exit the AFW Pump Rooms on the 14'-6" elevation of the Turbine i Building. In addition, automatic sprinkler coverage is provided for most of the general area on the 14'-6" and 31'-6" elevations of the Turbine Building (sprinklers are not installed directly over AFW Pump Rooms).. Deluge. waterspray systems are installed around the major
- lube oil components. Hose reels are located near the entrance to the
! AFW _ Pump Rooms and are strategically placed throughout the
- Turbine Building.
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B12399/ Attachment E Page 9 4.3.4 Fire Hazards Analysis The fire hazards analysis considered several aspects of the unsealed penetrations from the TDAFW Pump Room to the other areas. The aspects considered were: a fire originating on the 14'-6" elevation of the Turbine Building; a fire originating in the MDAFW Pump Room; and tM potential for any fire originating and spreading in the TDAFW Pump Room.
There are numerous ignition sources and combustibles that could be postulated to cause a fire on the 14'-6" elevation of the Turbine
. Building. Since the TDAFW Pump Room is located below this area, a l fire in fixed combustibles (nonliquid) would not threaten the Pump Room for the following reasons:
l Heat from the fire would rise up away from the open l penetrations. The grating at the ceiling of the 14'-6" elevation l would allow heat and smoke to rise to the upper elevations.
Fixed combustibles are not located near any of the penetrations, and burning debris would not pass through the penetrations.
Even if it did, there are no exposed combustibles in the TDAFW Room that would ignite and spread the fire.
A fire involving tube oil (or other combustible / flammable liquid) provides a somewhat more severe challenge to the open penetrations.
However, these open penetrations are equipped with 3" high curbs ;
around each opening, or they are provided with a watertight seal (see '
attached photographs). These curbs provide more than adequate dams to prevent liquid from flowing into the TDAFW Pump Room.
Their ability to prevent oil from entering the TDAFW Pump Room is i enhanced by floor drains in the 14'-6" elevation floor and the large condenser pit which would prevent the oil from reaching an j appreciable depth. The routing of the pipes through the unsealed l l openings is such that oil would not flow from upper elevations through the openings. Each pipe has at least one 900 elbow with a horizontal run prior to entering the penetration. Any oil flowing down the pipe from upper elevation would drip off at the elbow, or horizontal lengths, before entering the penetration. In addition to these curbs, fire spread into the TDAFW Room, due to a lube oil fire, would be mitigated by the heat rise away from the openings.
The tube oil components are protected by a waterspray deluge system designed to respond quickly and effectively to a lube oil fire. High flashpoint tube oil can be effectively controlled and suppressed by a waterspray system. The plant fire brigade is trained in the extinguishment of tube oil fires.
As stated above, the MDAFW Pump Room contains no measurable combustibles and, therefore, a fire in the room would be unlikely.
B12399/ Attachment E Page 10 The only credible fire scenario is overheated bearings or the motor on the pump. While this type of fire would produce smoke and some heat, it would not affect the Terry Turbine in the next room for the following reasons:
- The Terry Turbine can function even with smoke in the room.
The openings in the wall between the two AFW Pump Rooms are located near the ceiling. There are no combustibles passing through the openings (only pipe and conduit).
There are no exposed combustibles on either side to spread the i fire.
A fire originating in the TDAFW Room that could affect a TDAFW pump would most likely originate in the pump bearings. The same scenario described for the MDAFW Pump Room would apply and the same conclusion drawn; the fire would not affect the motor driven AFW pumps.
4.4 CONCLUSION
l l NNECO concludes that the existing barriers, including the unsealed i penetrations, provide adequate separation between the Turbine Driven l Auxiliary Feedwater Pump Room and adjacent fire areas. The technical l bases that justify this conclusion can be summarized as follows.
The unsealed openings are provided with curbs, or watertight seals, to prevent a lube oil spill from entering the TDAFW Pump Room.
The pipes entering the TDAFW Room have several 900 bends which l prevent tube oil from flowing along the pipes.
There are no continuous combustibles passing through the opening.
The most credible exposure is the Turbine Building general area, which is located above the TDAFW Room. Heat and smoke will rise away from the openings.
The tube oil concerns are mitigated by waterspray systems and floor l drains.
i The combustible loading in both the MDAFW and TDAFW Pump
, Rooms is very low, and a fire in one area would not reach the
! intensity to propogate into the adjacent area.
i l In summary, NNECO submits that the fire area boundaries between Areas R-3 l and R-12 provide adequate protection against the associated hazards.
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B12399/ Attachment E Page 11 5.0 Grate Floor 5.1 Information Provided to Staff Appendix R Areas R-5 (Fire Zone A-Sa) and R-2 (Fire Zone A-8b) are separated by an open grate floor (see Sketches I and 2). However, these two fire areas contain no redundant equipment. The separate fire area designations are provided only for convenience of NNECO. No Staff action is requested.
5.2 Discussion Appendix R Area R-5, Elevation (-)45'-6" (Fire Zone A-Sa) contains components associated with the Z-1 train of the LPSI system (cold shutdown). Combustible loading for this area is 9,318 BTUs/s.f. which represents a 7 minute fire duration.
On the (-)25'-6" elevation (above R-5) is Fire Zone A-8b which is part of Appendix R Area R-2. Zone A-8b contains cables associated with the Z-2 and Z-2 " swing" division of the charging system (hot shutdown). The fire loading in zone A-8b is 22,487 BTUs/s.f. or a 17 minute duration. (These fire load calculations represent fully loaded cable trays for analysis purposes.) Although Area R-5 and R-2 are separate Appendix R areas, a fire in R-5 could damage components in the zone A-8b portion of R-2. Note that, due to the low fire loading in these areas, the fire is not considered to extend above zone A-Sb.
A fire which starts in zone A-8a and spreads into zone A-8b could (in the worst postulated case) damage LPSI pump A (Z-1 division cold shutdown equipment) and affect cabling in A-8b associated with the Z-2 division of the charging system. In this case, safe shutdown capability is maintained since operability of the Z-2 division of LPSI cold shutdown equipment and the Z-1 division of charging hot shutdown equipment is not affected.
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