ML19345H611

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Answers to Interrogatory 7-3 of Second Set of Interrogatories Re Containment Supply Relief Sys.Certificate of Svc Encl
ML19345H611
Person / Time
Site: Big Rock Point File:Consumers Energy icon.png
Issue date: 05/18/1981
From: Gallo J
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.), ISHAM, LINCOLN & BEALE
To:
BIER, MILLS, CHRISTA-MARIA, ET AL
Shared Package
ML19345H610 List:
References
ISSUANCES-OLA, NUDOCS 8105210395
Download: ML19345H611 (20)
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{{#Wiki_filter:.' { }. 5/18/81 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of ) ) Docket No. 50-155-OLA CONSUMERS POWER COMPANY ) (Spent Fuel Pool ) Expansion) (Big Rock Point Nuclear Power Plant) ) ANSWERS OF CONSUMERS POWER COMPANY TO INTERROGATORIES (SET II) PROPOUNDED BY CHRISTA-MARIA, ET AL. Pursuant to 10 C.F.R. S 2.740b, Consumers Power Company (" Licensee") hereby submits answers to Interroga-tory 7-3 of the above-entitled Interrogatories. Interrogatory 7-3 Please describe and explain the containment supply relief system. A. Answer The reactor cont tinment building (containment) for Big Rock Point is designed for continuous ventilation. Plant design utilizes continuous ventilation to provide contamination control for access to operating equipment and cooling to maintain critical equipment operable. During warm weather, the continuous ventilation is essential to maintain the containment temperature within the limits described in the Final Hazards Summary Report.

For purposes of this question, the containment ventilation supply relief system is contained in the following areas: The ventilation building (air shed), containment and the plant exhaust stack. The air shed is attached to the outside of con-tainment in an area between containment and the plant exhaust stack. The air shed houses louvers, filter and heating coils for conditioning and tempering the air before reaching the containment. Further, the air shed contains the supply and exhaust lines, the inlet air plenum and isolation valves which are closed automatically after any scram, loss of power or high radiation near spent fuel pool. The containment houses the plant supply air fans with damper controls, the containment exhaust plenum, and two containment vacuum relief lines which are to prevent excessive external pressure from causing damage { l to the containment's integrity. The plant exhaust stack houses the plant exhaust plenum, plant exhaust fans and air make-up damper with automatic controls to maintain rated air flow out the stack when p? snt demand falls below normal. Basical.J, air is drawn through the louvers into the air shed,, asses through the heating coils, filter, into the intake plenum, is drawn from the intake plenum

, into the supply line, through the supply isolation valves by the supply air fans and flows into contain-ment. A,f ter the air passes through the containment areas, the air is collected in the containment exhaust plenum and drawn (containment maintained at slightly negative pressure) through the exhaust line, into the plant exhaust plenum by the plant exhaust fans, which discharge to the plant exhaust stack. B. Documents Relied Upon 1. Big Rock Early (Pre) Operations Manual (Pages 219-232 Enclosed). 2. Letter CPCo to NRC (Ziemann) dated 11/29/78. Big Rock Point Plant - Additional Information Relative to Fuel Handling Accident in Containment. 3. Letter CPCo to NRC (Ziemann) dated 12/29/78. Big Rock Point Plant - Containment Purging During Normal Plant Operations. C. Documents Reviewed But Not Relied Upon 1. Letter NRC to CPCo (Bixel) dated 10/16/79. Big Rock Point Plant - Related to Containment Purging. 2. Letter CPCo to NRC (Ziemann) dated 12/3/79. Big Rock Point Plant - Containment Purge System, CPCo Response for Additional Information. l

-4 D. Further Activities It is anticipated that changes will be made to the Containment Purge System as indicated in the letter referenced below: 1. Letter CPCo to NRC (Ziemann) dated 3/14/80 - Big Rock Point Plant Containment Purge System, Single Failures. a >l A _-_ kb Jopfh Ggilo, Esquire O W of the Attorneys for Consumers Power Company ISHAM, LINCOLN & BEALE 1120 Connecticut Avenue, N.W. Suite 325 Washington, D. C. 20036 (202) 833-9730

I@TED, CORPISPONDENC5! UNITED STATES OF /J! ERICA NUCLEAR REGULATORY COMMISSION ~g g BEFORE THE ATOMIC SAFETY AND LICENSING BOARD 9 4 e s DCCK g In the Matter of ) ep.,, ) f MAY.1 9Igh, f CONSUMERS POWER COMPANY ) Docket No. 50-155 k.3C'h B m 7 Dj ) (Big Rock Point Nuclear Power Plant) ) C $h.[zm ~ ~ AFFIDAVIT OF EDWARD R COOPER I, Edward R Cooper, of lawful age, being first duly sworn, do state as follows: I as employed by Consumers Power Company as a staff engineer in the Operatine Service Department. I have the responsibility within the Company for technical review and coordination aspects of the pro-posed spent fuel pool expansion at the Big Rock Point Plant. My resume is attached. 1 I have primary responsibility for answering Interrogatory 7-3. l To the best of my knowledge and belief, the state =ents in this l affidavit and in the response to the interrogatory listed above are true ud cerrect. P A J /2 C - Edward R Cooper Subscribed and sworn to before me this 2nd day of October, 1980. fbed-Y $4hAS l / f Notary Public, Jackson County, Michigan, =y co _.ission expires l March 26, 1983 I i

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'I \\ N In the Matter of ) ) Docket No. 50-155-OLA CONSUMERS POWER COMPANY } (Spent Fuel Pool ) Expansion) (Big Rock Point Nuclear Power Plant)) CERTIFICATE OF SERVICE I hereby certify that copies of CONSUMERS POWER COMPANY'S ANSWERS TO INTERROGATORIES (SET II) PROPOUNDED BY CHRISTA-MARIA, ET AL. in the above-captioned proceeding were served on the following by deposit in the United States mail, first-class postage prepaid, this 19th day of May, 1981. Herbert Grossman, Esquire Atomic Safety and Licensing Atomic Safety and Licensing Board Panel Board Panel U.S. Nuclear Regulatory U.S. Nuclear Regulatory Commission Commission Washington, D.C. 20555 Washington, D.C. 20555 Atomic Safety and Licensing Dr. Oscar H. Paris Appeal Board Panel Atomic Safety and Licensing U.S. Nuclear Regulatory Board Panel Commission U.S. Nuclear Regulatory Washington, D.C. 20555 Commission Washington, D.C. 20555 Docketing and Service Section Office of the Secretary Mr. Frederick J. Shon U.S. Nuclear Regulatory Atomic Safety and Licensing Commission Board Panel Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Janice E. Moore, Esquire Washington, D.C. 20555 Counsel for NRC Staff U.S. Nuclear Regulatory Commission Washington, D.C. 20555 l

. Mr. John O 'Neill, 'I Ms. JoAnne Bier Route 2, Box 44 204 Clinton Maple City, Michigan 49664 Charlevoix, Michigan 49720 Ms. Christa-Maria Mr. James Mills Route 2, Box 108C Route 2, Box 108 Charlevoix, Michigan 49720 Charlevoix, Michigan 49720 Herbert Semmel, Esquire Urban Law Institute Antioch School of Law 2633 16th Street, N.W. Washington, D.C. 20009 Qe - Is _ s_$$c gJos%hGallo ~ _ _ _ ~ _ _ -. _ _ _ _... _. _ _ - -

~. N [ 219 J Ocey.g vs.., RE1.XTED CORM.WMWCI i I 9198l e C CONVESTIOUAL PLANT SYSTE'S (Contd) % :37 HEATING AUD VEUTILATING SYSTE4 (Contd) U Description (Contd) 'l / 2, E. ReactorBuildingHeatingandCoolingSystem(Conid) SV-9173 - Mot St Ct SV - Oper Inlet Damper Po - Pipe Way and Steam Drum Cool. Unit 3 C-20 PO-9435 - Inlet Air Damper Positioner - Pipe Way and Steam Drum Cool. Unit A Local P0-9434 - Inlet Air Damper Positioner - Pipe Way and Steam Drum Cool. Unit 3 Local TC-9265 - Inlet Air TC - Pipe Way and Steam Drum Cool. Units - Operates CV-9459 C-20 CV-9459 - SWR Flow Begulation - Pipe Way and Steam Drum Cool. Units A and B Local i TI-9329 - SWR Pipe Way and Steam Drum Cool. Units Local TI-9330 - SWS Pipe Way and Steam Drum Cool. Units Local YS-9642 - SWS Pipe Way and Steam Dzum Coel. Units Local F. Reactor Building Ventilation System O ve=t11 tie = tr to the =eeet r h=11a1=8 1 uvr11e*

  • rates varying from 0 cfm to 14,500 cfm and is so controlled as to =ain-4 tain a slight negative pressure within the building itself.

1 Two, full capacity, ventilation supply air fans are pro-vided in this system and discharge ventilation air, through a grill, directly into the general areas of the sphere. A ventilation building, or air shed, attached to the sphere in a line between the sphere and stack, contains the outdoor air louvers, filters and air heating coils for tempering incoming air. Each supply air fan suction has an open-shut damper positioner with initia, tion integral to the fan starting circuit, and inlet vanes controlled i by indoor, outdoor differential pressure, to regulate air flow. A reactor cuilding vacuum relief line with damper control integral to supply air fan motor starting circuits is cpen to the build-ing when both supply air fans are stopped, insuring a free path for out-side air in the event that building vacuum =ust be relieved. Outside air enters the system through cutside air louverc O in the e1= ehed, to the air r1ecum. It is >en Passed throuch eir filters ( ), equipped with DPS-9059 which alarm: high dir-ferential pressure (replace reactor building supply air filters) on Panel

l i i 220 i-C CONVEUTIONAL FLUiT SYSTES (Contd) l HEATING AND VETTILATING SYSIE4 (Contd) { Description (Contd) l F. Reactor Building Ventilation System (Contd) { C-20. Air flow from the outside air plenum is controlled by HS-9004 on C-26 (HS-900h is a maintained contact push button), which selects face damper and temperature control on either "A" or "B" air heatin6 units i and puts the alternate unit on a stand-by basis, in the event that the l operating unit cannot maintain a preset minimum temperature. TS-9304-1 opens Unit "A" face damper on high temperature, downstream of the heater; TS-9304-2 opens the face damper of the alternate unit in the event of lov discharge air temperature from the heater. TS-9303-1 and 9303-2 perform the same function on Unit "3." l Steam flow to the air heater coils is controlled by I TS-9313, with a sensor located in the outside air plenum. Contacts of TS-9313 elose on high temperature, energizing Sv-9171 to close CV-9460 and CV-9461, simultaneously; low temperature opens contacts in TS-9313, { de-energizing SV-9171 to open CV o460 and CV-9h61, allowing steam flow from the plant heating boiler to both air heaters. During the heating season, the steam valves for both coils are fully open and are not f modulated to avoid freezing. j Downstream of the warm air, or bypass air plenum is a-I temperature controller (TC-9266) which regulates inlet dampers to the two air heaters (Unit "A," PO-9401; Unit "3," Pc-9h02) within the high and low settings of TS-9303,1 and 2 (Unit "B") and TS-9304,1 and 2 (Unit "A") and controls the bypass damper (P0-9415) around both air l heaters. High te=perature in the ventilation supply air opens the by-pass damper. TS-9302 alarms low ventilating air temperature on Fanel C-20 and TI-9333 indicates same on Panel C-26. Two 2k" diameter pneumatic cylinder and spring-operated check and butterfly valves, connected in series, are provided for the supply air inlet and for the exhaust air outlet to isolute the reactor building ventilation air. These valves are located immediately outside { the sphere and within the air ched. The valves are arranged for spring

221 O CONVETIONAL PIRC SYSTEG (Contd) HEATING AND VE TIlATIUG SYSTEM (Contd) Description (Contd) F. Reactor Building Ventilation System (Centd) closing and air opening. They are automatically closed by the safety circuit during all scrams and =ay_ be mually closed by ES-9001 (re-actor building ventilation isolation valve control switch) or by "close penetrations and scram" (SS) on Section C of main cons ~ ole. Both venti-lation inlet isolation valves (CV 1496, CV-4097) have position switches (PoS-9101, Pos-9102) controlling position indicator lights on Section 2, MCP. Inside the reactor building, in the supply air duct, is a temperature element (TE-9362) with temperature indication (TI-9338) f on C-20, and a pressure switch (PS-9209) which opens the inlet da=per I to and starts the stand-by fan motor on loss of vacuum in supply air s duct-to fans. Another pressure switch (PS-9202) alar =s on Panel C-20 on loss of vacuum. Two, full capacity, supply air fans located adjacent to l the ventilation penetrations (A and 3) driven by 10-hp notors with run, off, and stand-by switches, controlled 'at MCC Bus 2D, are connec'ted to the supply air plenum discharge air through a grill directly into the i reactor building general area. Inlet dampers to the supply air fans are solenoid controlled (SV-9161-PC-9410, Fan A; SV-9160-P0-9hil, Fan 3) full open or shut with solenoid energizing integral to the fan motor { starting circuits so that, at anytime either fan =otor is energized, the inlet damper is open. Inlet vcnes to permit varying the supply air rate from 3 approx 1=ately 3C% to full fan capacity are positioned by a differential i pressure controller (EPC-9071; FO-9412-Fan A, Po-9kl3-Fan 3) which con-l trols supply air flow so as to =aintain a slight negative pressure within j the reactor building. Differential pressure is indicated (DPI-9081) and annunciated (EPS-9055-high, DPS-9056-low) on Panel C-20. Differential Fressure Controller 9071 has two solenoid-f, h operated (SV-9155, SV-9156) isolation valves on the external pressure

222 C CONVERIONAL pLAW SYSTE4S (Contd) HEATING AND VSITILATING SYST24 (Contd) Description (Contd) F. Reactor Building Ventilation System (Contd) probe due to the possibility of reactor building pressure rupturing 1 the controller and exht. sting through the external probe. These valves are connected in series with the ventilation isolation ralves and close on the same signalis. In the event of closure of reactor building isolation valves and a simultaneous build-up of negative pressure within the building, a differential pressure switch (DPS-9052 in C-26) is provided j to annunciate at 1-1/2" Hg vacuum on (Panel ) and a differential pressure switch (D?S-9051 in C-26) is provided to override all other signals and open supply air isolation valves (CV-kO96 and CV-LO97) to break vacuum at 2" Hg vacuum. A vacuum relief is provided inside the reactor building, {% on the supply air duct, upstrea= of the supply air fans. The vacuum relief damper (PO-9414) is controlled by SV-9159 in such a manner that, when either supply air fan =otor is energized, SV-9159 is energized, closing the vacuum relief damper. When both supply air fan motors are i de-energized, SV-9159 is de-energized, opening the vacuum relief da=per, which gives outside air an unobstr2cted route into the reactor building, f should DPS-9051 open the supply air isolation valves to relieve a build-1 ing vacuum. Ventilation air flow through the reactor building rooms and passagesis equal to the induced draft exhaust flov to the building I. exhaust plenum (core spray tank room - 422) created by the plant ex-I haust fans in the stack. Reacter building's exhaust routes, flows and controls are as follows: 4 l Control rod drive pump room (403), shutdown heat ex-changer and pump room (kl7) and fuel pit filter room (419) enhaust through the same duct with a total flow of 460 to 2300 cfm. Each room has a =anually positioned exhaust damper and the main duct has automatic ( l da=per positioning (p0-9408), operated by TC-9268 (operating range 80 F to 120 F, set point 100 F) located in the control rod drive pump room (403). s

. ?, 223 I O Convrur'ronic Print SrSrmS (Contd> HEATING AND VENTILATING SYSTEM (Contd) i Description (Contd) t F. Reactor Building Ventilation System (Contd) Scram valves and accumulator room (kO5), control rod t 1 access room (h07), 200 cfm each with manual damper control only. Core spray. tank room (h22, exhaust plenum room), 200 cfm, manual damper. Regenerative and nonregenerative heat exchanger roem (k39), cleanup demineralizer pump room (426) LOO and 200 cfm, respec-l tively, and manual damper. l Instrument room (h42), storage room (4hl) 200 cfm each, manual damper - fuel pit, remote manual controlled (PO-9437, HS-9030 on t j j C-20) damper, 2100 to 4500 cfm. Pipe way and steam drum area, LOCO to 6000 cfm, remote i manual controlled (PO-9h0k, HS-9026 on C-20) hper. The reactor building's clean and dirty sumps have a h" l 0 exhaust line, with a Crispin air valve, which goes directly to the ex- [ haust plenum. l The reactor building's pipe way and steam drum area ventilation is provided by the pipe way and steam dntm cooling units (described in RB heating and cooling system), with a small acount (2000 cfm, maximum) added around the reactor head shield plug by the refueling area H and C units. A total of 30,000 cfm cooled air is discharged into this area with 2000 cf2 to the reactor annulus on a level with the bottom of the extension tank (HS-9028 on C-20, PO-9406), 1000 cfm below the reactor and 1000 cfm into the ion tubes which discharges back into the reactor annulus (HS-9027 on C-20, PO-9405). The remainder of this ventilation air is discharged into the pipe way and steam dntm area at four elevations (elevation 595 ', PO-94hl-ES-9034 o. C-20; elevation [ 616', PO-94h0-HS-9033 on C-20; elevation 635 ', IV-9439-HS-9032 on C-20; i elevation 650', IV-9438-Es-w 31 on C-20) along the south vall. Of the total air exhausted from this area (a 36" x 36" exhaust grill and duct located above the stesa drum, SE cornerj, h000 to L'000 cfm cre routed to the plant exhaust system with the remainder being recirculated and u

s 224 J e C i CONVENTIONAL PLAITf SYSTE4S (Conta) I j HEATING AND VENTILATING SYSTC4 (C:lrntd) Description (Cont'd) F. Reactor Building Ventilation System (Contd) i recooled in the drum and pipe way cooling units. Make-up air at a rate f equal to the air exhausted (4000 to 6000 cfm) is constantly being in-i troduced into this system by infiltration through minor openings and 1 } through a make-up damper (located on the south side of cooling unit PO-9ho3) which is controlled by a differential pressure controller (DPC-9072), set to maintain a slightly more negative pressure in the drum area than in the reactor building itself. Differential pressure 90 -1 v n e -20 DPS-90 lo rs re i I also override DPC-9072 on low pressure in the pipe way to open the make-up damper. Temperature within the ion tubes (TE-9372 to TE-9378), l the reactor annulus (TE-9352, 9355, 9363, 9364, 9365, 9366, 9367, 9368, C 4 ?: 9369, 9370, 9371), the pipe way and steam drum area (TE-9351, 9355, ~ 9357, 9360) are all indicated (TI-9338) on C-20. So as to decrease air-borne radiation hazards to per-i sonnel during refueling operation, a downward flow of air is created around the reactor vessel head and ion tubes L', closing pneu=atic l dampers PO-9kO5 (HS-9027 on C-20) and PO-9k06 (HS-9028 on C-20). This i vill allow air from the general area to flow downward around the vessel } head and through the ion tubes. l Steam leak detection for the reactor building's pipe way and drum area is provided by a high dev-point detector (ME-9601, a Foxboro Deveell model) which alarms MS-9626 - Minneapolis-Honeywell) and is a recorced (MR-9621) - Minneapolis-Honeywell, RTD indicating with 30-day recording chart) on Panel C-20 with its sensor located in the Pipe way air recirculation, recooling duct. 'l 2he following instzumentation has been included in the reactor building ventilation description: TC-9266 - Reactor Building Vent Air C-26 (_ ^ TC-9268 - RB Control Rod Drive Pump Room Local 4 i

225 I i O C01:va TIO11At Ptit:T SYSTre (Contd> HEIGG MID VEITIIATING SYSTE4 (Contd) Description (Contd) i F. Reactor Building Ventilation System (Contd) DPS-9051 - R3 Vacuum Breaker C-26 l DPS-9052 - R3 Vacuum Breaker C-26 DPS-9053 - R3 Pipe Way H1 h Pressure C-20 6 DPS-9054 - R3 Pipe Way Lov Pressure C-20 DPS-9055 - R3 High Pressure C-20 DPS-9056 - R3 Low Pressure C-20 i DPS-9059 - R3 Supply Air Filters C 26 f DPI-9081 - R3 Differential Pressure C-20 DPI-9082 - R3 Supply Air Filters C-26 DPI-9085 - R3 Pipe Way Differential Pressure C-20 ,DPC-9071 - P3 Differential Pressure C-20 DPC-9072 - R3 Pipe Way Differential Pressure C-20 TS-93C2 - Reactor Building Vent Air Lov Temperature C-26 TS-9303 - P3 Ventilating Air Heating Coil Lov Te=perature C-26 TS-930k - R3 Ventilating Air Heating coil Low Temperature C-26 TS-9313 - RB Vent 1hting Air Steen Coil C-26 TS-9305 - R3 Shell Low Temperature Local TS-9306 - R3 Shell Low Te=perature Local SV-9151 - R3 Ventilating Air Isolation Valve C-26 SV-9152 - R3 Ventilating Air Isolation Valve C-26 SV-9157 - R3 Ventihting Air Coil Damper C-26 SV-9158 - as Ventilating Air Coil Damper C-26 SV-9159 - R3 Vacuum Breaker Damper C-22 SV-9160 - F3 Supply Air Fan Isolation Damper C-22 SV-9161 - RB Supply Air Fan Ischtion Dmper C-22 SV-9171 - R3 Ventilating Air Steam Coils C-26 PO-9412 - RB Supply Air Fan "A" Inlet Vanes Local i PO-9hl3 - RB Supply Air Fan "3" Inlet Vanes Local IV-9h01 - 33 Ventihting Air Coil Damper Local l q PO-9kO2 - BB Venti hting Air Coil Damper Local 1' L PO-9403 - FB Pipe Way Make-up Air Duper Local I 'l

226 O I CCNVENTIONAL PIRTP SYSTEMS (Contd) EATING AND VENTILATIUG SYSTE4 (Contd) Description (Contd) F. Reactor Building Ventilation System (Contd) PO-9404 - RB Pipe Way Exhaust Damper Local PO-9406 - Reacter Annulus Supply Air Damper Local PO-9408 - RB Control Rod Pump Room Damper Local PO-9410 - RB Supply Air Fan "A" Isolation Damper Local PO-9411 - RB Supply Air Fan "B" Isolation Damper Local PO-9414 - RB Vacuum Breaker Damper Local PO-9415 - RB Ventilating Air Bypass Damper Iccal PO-9b37 - Fuel Pit Exhaust Damper Local PO-9405 - Ion Tubes Supply Air Damper Local HS-9001 - Ventilating Isclation valve Control C-01 ES-9004 - RB Ventilating Air Heating Coils C-26 HS-9026 - RB Pipe Way Exhaust Damper C-20 O HS-9028 - Reactor Annulus Supply Air Damper C-20 HS-9030 - Fuel Pit Exhaust Air Damper C-20 HS-9031 - RB Pipe Way Supply Air Damper C-20 HS-9032 - RB Pipe Way Supply Air Damper C-20 HS-9033 - RB Pipe Way Supply Air Damper C-20 HS-9034 - BB Pipe Way Supply Air Damper C-20 HS-9027 - Ion Tubes Supply Air Damper C-20 CV-9460 - BB Ventilating Air Heating Coil Steam Valve Local CV-9461 - RB Ventilating Air Heating Coil Steam Valve Local CV-9496 - RB Ventilating Air Isolation Check Valve Local t I CV-9497 - RB Ventilating Air Isolation Butterfly Valve Local TI-9333 - RB Ventilating Air Supply C-26 j TI-9338 - RB Pipe Way and Reactor Annulus C-20 PoS-9101 - Ventilating Air Isolation Valve Indicator j PoS-9102 - Ventilating Air Isolation Valve Indicator TE-9351 - RB Pipe Way and Reactor Annulus Local 4 TE-9352 - RB Pipe way and Reector Annulus Local ( i TE-9353 - RB Pipe Way and Reactor Annulus Local TE-9354 - RB Pipe Way and Reactor Annulus Local I i

1 227 i llO CONVEm0NAL PWf SYSM (Contd) I HEATING AND VENTILATING SYSTEM (Centd) Description (Contd) F. Reactor Building Ventilation System (Contd) TE-9355 - RB Pipe Way and Reactor Annulus Local TE-9357 - RB Pipe Way and Reactor Annu3us Local TE-9358 - RB Pipe Way and Reactor Annulus Local l TI-9359 - RB Pipe Way and Reactor Annulus Local TE-9360 - RB Pipe Way and Reactor Annulus Local TE-9362 - RB Pipe Way and Reactor Annulus Local i TE-9363 - RB Pipe Way and Reactor Annulus Local TE-9364 - BB Pipe Way and Reactor Annulus Local TE-9365 - RB Pipe Way and Reactor Annulus Loce.1 I TE-9366 - RB Pipe Way and Reactor Annulus Local g TE-9367 - RB Pipe Way and Reactoz Annulus Local TE-9368 - RB Pipe Way and Reactor Annulus Local TI-9369 - BB Pipe Way and Reactor Annulus Local O TE-9370 - P3 Pipe Way and Reactor Annulus Local TE-9371 - RB Pipe Way and Reactor Annulus Local TI-9372 - Seven Ion Tubes Local TE-9373 - Seven Ion Tubes Local TE-9374 - Seven Ion Tubes Local TE-9375 - Seven Ion Tubes Local TE-9376 - Seven Ion Tubes Local j TE-9377 - Seven Ion Tubes Local TE-9378 - Seven Ion Tubes Local PS-9202 PS-9209 ME-9601 - RB Pipe Way Steam Leak Local MS-9626 - RB Pipe Way Steam Leak C-20 I MR-9621 - RB Pipe Way Steam Leak C-20 l 1 G. Ventihtien Exhaust i Ventilation exhaust from all plant areas, except a few specific cues already described, is routed to an exhaust plenum in the I base of the 2h0' concrete vent stack. From this plenum, either one of i i i

228 O CONVE:ITICITAL PINiT SYSTE4S (Contd) { HEATIIiG AIiD VEIITILATIITG SYSTE4 (Contd) i. Description (Contd) G. Ventilation Exhaust (Contd) two motor-driven plant exhaust fans takes a suction and dischar6e up i the stack. Total air flow out the stack is 30,000 cfm. '"his continuous air flow rate is maintained by a set of automatic dampers (PO-9423 via PC-9222) admitting from o efm to 19,100 cfm of outside air to the plenum, compensating for variations in ventilation exhaust air flow. Ventila-tion exhausts to this plenum are: i 1 Plant Exhaust Fan Room 16" x 8" 0-500 Cfm Temperature Controlled Containment Building 24" Diam 10,000-14,500 Cfm Diff Press. Controlled Cond Demineralizer i Room 12" Diam 500 Cfm Radwaste Area 18" Diam 1500-h000 Cfm Manually Controlled Balance of Turbine and Service Bldg 30" Diam 9900-19,000 Cfm Manuany Contro ned (, In addition to manual control of the exhaust from the l I turbine and service buildings, a flow limiting element (FE-9592) vill ~ regulate the exhaust from the following areas to 3900 cf= through FC-9571 which will position PO-9433: 500 Cfm Decontamination Area Hood L Shop (Rooms 103, 104 10hA) - 2000 Cfm Turbine ID (Room 112) 200 Cfm j LO Storage (Room 111) 200 Cfm i Laundry and Access Control - 1000 Cfm In addition to the temperature-controlled fan (PO-9420) room dampers (0-500 cfm in above table), further control over fan room temperature and air flow is available in the manually operated louvers in the outside doors and an electric unit heater. This heater has a temperature control (TC-9275) and is powered from Panel P-lk, MCC Bus 1D, Breaker $2-lD33 The containment buildin6 exhnust $oes to the stack ex-l haust plenum from an exhaust plenum in the enclosure via a 2h" pipe, ( equipped with a flow damper (PO-9409) controlled by IC-9221, on the t i

229 OV CONVETTIonAL PLAUT SYSTEG (Contd) HEATING AND VBITILATIUG SYSTH4 (Contd) Description (Contd) G. Ventilation Exhaust (Cantd) enclosure exhaust plenum. This flow dcmper controls the amount of ex-haust air to maintain a suitable pressure in the exhaust plenum ( ), Since varying the flow to accommodate changes in supply air flow. supply air to the enclosure is controlled by a differential pressure controner (DPC-9071) to maintain a slight negative pressure in the buildir f, it is this dPC which exercises effective control of the ex-haust air flow. The 24" containment building exhaust line also has a pair of air-operated, solenoid controlled (SV-9153 and SV-9154) isolation valves (CV-ho94 and CV-ko95). CV-ko94 is a spring-closed check valve, checking outward air flow when closed. CV-ko95 is a spring-closed butterfly type valve. These valves are closed by tripping of the solenoids by the safety system upon an scrams and may also be closed by ES-9001, reactor building ventilation isolation valve control switch, O on Section "A" of the control console. These valves have position switches (PoS-9103 and PoS-9104) and controlling position indicator f lights on Se : tion 2, MCP. In addition, this 24" vent exhaust line has temperature element (TE-9361) with indication (TI-9338) on Control Panel I C-20, and a flow element (FE-9591), with indication (FI-9561) on Panel C-20 Control Panel C-20 is next to MCC Bus 2D, near the personnel lock. Each of the plant exhaust fans has a pneumatic-operated i (Fan A, Po-9k21; Fan B, Po-9k22), solenoid controned (A, Sv-916T; 3, j SV-9168) discharge damper. The solenoid is in paranel with the fan i [ g motor control circuit, and opens the damper whenever the motor is With a fan motor hand started, whether by hand switch or automatically. switch in the " stand-by" position, and the other fan switch in the "run" I position, the fan on " stand-by" vi.'1 be started automatically whenever l the pressure in the stack exhaust plenum increases to aset value( ), l indicating failure of the other fan (PS-9204). Another pressure switch f (PS-9203) operates an alarm - plant exhaust fans trouble - on Section 2 i This same annunciator win also be tripped by Overload Centact of MCP. i I l

230 Av CONVENTIONAL PLANT S'ISTDS (Contd) HEf. TING AND VENTILATING SYSTEi (Contd) Description (Contd) G. Ventilation Exhsust (Contd) h2-1D15 in the breaker for Fan A, or k2-lD25 for Fan 3. The hand switches for these fan motors are on the breakers in Panel P-1k, Bus 1D. There is a locally mounted pressure indicator (PI-9214) at the exhaust plenum indicating the pressure in the plenum. H. Remote Area Heating Tabulated below are certain areas or rooms which have locally mounted and controlled electriu unit heaters '.rith fans. Power Temp Area Wattage Feed Breaker Controller Condensate and Demin-eralizer Water Tank's Valve Pit 1 Kw Lighting Panel 3L 21 TS-9314 Post-Incident Cool-ing Equipment Room 5 Kv MCC Bus 1D 52-lD34 O Screen House 24 KV MCC Bus 20 52-2C23 Stack (Instru=ent Room) 5 Kv MCC Bus ID 52-lD33 TC-9275 Diesel Generator Rocm 6 KV MCC Bus 2C 52-2C26 Well House 1 Kv Li hting h_nel 31L 1 6 Calibration Facility 5 Ku MCC Bus 1D 52-lD35 'Ihere 4e also space heaters in the motors of Circulating Water Pumps No. 1 and No. 2, totaling k80 watts, fed from Lighting Panel 10L, Breaker No. 1, in the screen house. Principle of Operation The ventilation system for the three main buildings (reactor, turbine and service buildings) of the Big Rock Point Nuclear Plant has been designed to take advantage of natural, forced and induced ventilation in such a manner as to create a constant air flow from areas with negligible air-borne radioactivity potential to areas of hi her air-borne radioactivity potential. This system of ventilation 6 vill serve to minimize any spread of air-borne radioactivity through ( an induced draft exhaust system from various areas throughout the plant to the stack.

231 O CONVD1TIONAL PIAllT SYST24S (Contd) HFATING AND VSCIIATING SYSTS4 (Contd) Principle of Operation (Centd) The reactor building's ventilation system is forced and induced only and is designed for the same inward air flow from the periphery to the center of the building. Provision has been made for manual reactor. building ventilation isolation and for automatic isola-tion in the event of any scram. The turbine and service buildings are heated by forced hot air and convection heaters controlled by pneumatically operated room or area thermostats. The primary plant heating medium is an oil-fired package boiler which supplies 3160 pounds per hour of 15 psig steam to the various heating units. Cooling air to the service building is provided by cir-culating service water through coils of the various heating and cooling units with forced cooled air following the ventilation air flow (control O roo= the o=17 exceptica)- Tcr*1= room cootics nring the su==er =oatas may be achieved with natural circulation (due to ec:rtection) by opening louvers near ground level and exhausting this air through canually l controlled louvers near roof level along the west side of the buil' ding-The reactor building's heating and cooling systems are somewhat more complex due to possible isolation and the fact that the reactor annulus and steam drum and pipe way area cast be cooled through-Two air cooling units out any periods of reactor operation at power. are provided for this area, utilizing plant service water flow through l cooling coils, as the primary cooling medium. Five area heating and j cooling units served by a closed loop demineralized water heating and cooling agent serve to heat or cool the general area of the sphere (area outside the concrete structure). Heating or cooling is achieved by routing either steam or service water through the tube side of cne or l-both heat exchangers of the closed loop system and the water is circula-l ted by one or both recirculation pumps to provide either a heating or I cooling agent to these forced air units. As a further source of winter { i O heating, incomins ventitation etr 1s tenvered by vessine it across heet-ing coils located in the ventilation air shed. I

232 C CONVENTIONAL PLANT SYSTHEI (Contd) EATING AND VDT2ILATING SYSTE4 (Contd) principle of Oteration (Contd) The plant ventilation exhaust system terminates at a 2k0' stack which consists of two full-capacity vane axial fans, make-up. air damper with automatic controls and an exhaust plenum where ducts from areas.and systems ter=1nate. An exhaust flow of 30,000 cfm.out the stack is maintained with plant ventilation being of secondary impor-I tance to off-gas dilution. When ventilation demands fall below main-i tained air flow, the deficit is compensated for by make-up air. Operating Instructions A. Steam Heating Boiler To Start From Summer Lay-Up l. Check Breaker 52-1A33 closed. 2. Check make-up water supply to condensate tank open and drain closed. Ascertain tank level normal on gauge glass. 3 Check boner water gauge glass valves open, drains C closed and check fuel oil filw r for sediment. 4 4. Close boiler control breaker and one feed pump breaker on panel below burner - make sure sufficient make-up is supplied to prevent pump running dry. 5 When boiler is filled to proper level (3-1/2" in gauge glass) and feed pump stops, close other feed pump breaker and i valve in fuel oil supply and bypass lines. 6. Close burner motor breaker - burner should start. If it does not, attempt to reset "Fireye" controller. 5 7 Observe that burner shuts off at 14 5 psig. Open 6" gate valve steam outlet. Burner should restart at 10 5 psis. j 8. If controls do not function, as cutlined above, re-l fer to manufacturer's instzuctions (Kewanee 876 and Iron Fireman burner I control). 1 Operating Checks 1. Cauge cock and blev down valves on water column and water glass - blev down daily. ( 2. Blow down or drain approximately ten quarts of water from boiler - monthly.

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.EEI LTED CORRESPONDEm C0!ilh,,.V u 9 bi)'. If o.m.,.. ome.. m2 w.. wen...n Av.au J.Ch.on. WCheg.a 4G201. Are. Coco St7 7uG-oS So U L November 29, 1978 CCcVEtu 1 r..., 3 l M M.1 91983. -ic Director, Nuclear Reactor Regulation Att: Mr Dennis L Ziemann, Chief ' Fjeefry Operating Reactors Branch No 2 .. M f ce M // US Nuclear Regulatory Commission e. Washington, DC 20555 4 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - ADDITIONAL INFORMATION RELATIVE TO FUEL HANDLING ACCIDENT IN CONTAINMENT Your letter dated May 22, 1978 requested Con::umers Power Company to provide additional information relating to the engineered safety features which are available to mitigate the consequences of a postulated fuel handling accident inside containment (FHAIC) at the Big Rock Point Plant. The purpose of this letter is to provide the requested information. Your letter requested the following four items: 1. Provide system discriptions (including PGIDs and control system logic and schematic diagrams) and analysis to demonstrate the extent to which existing systems required to function during the FHA!C cceply with the criteria established in the Hazards Su= mary Repert for engineered safety features. 2. Pro"ide a description of the extent to which these systems will comply with the current NRC criteria for engineered safety feature systems which are listed in the NRC Standard Review Plan, NUPIG-75/087. 3. Explain why it is not necessary to have these systems meet the current NRC criteria for ESF systems. 4. Information regarding proposed changes to the existing plant should be provided. This information should be as described in Regulatory Guide 1.70. pmP 6 O P .g 9 1 20 'lC) 3 0

2 O ~ Response 1 System descriptions are provided via the fol'.owing documents: 0740G30114 Shset 2 Schematic Disgram - Air, Screen, (Attachment I) Fire and Post-Incident Systems 0740G40125 Rev P Reactor Building Ventilating, Heating (Attachment II) and Cooling System P&I Disgrams Sketch No 1 Logic Diagram for Air Supply alves, (Attachment III) Scheme 8501 ~ Sketch No 2 Logic Diagram for Exhaust Vent Valves, (Attachment IV) Scheme 8512 Analysis No I Written System Logic Description (Attachment V) An analysis of the existing containment isolation system shows that recent modifications to the system (ie, automatic isolation on high radiation, vacuum relief through the 24-inch supply and exhaust lines) have enhanced the system's ability to comply with the criteria established in the Hazards Summary Report. The Hazard, Surcary Report describes two 24-inch ventilation openings; one for supply, the other for exhaust, which are closed automatically within six seconds after any scram signal or loss of power. As described in the above , documents, these two closing features are still present with the additional feature of high radiation closing also available. The Hazards Summary Report also describes a vacuu:n relief line which is intended to prevent excessive external pressure from causing damage to the containment's integrity. The vacuum relief modification has also enhariced this system's ability to comply with the vacuum relief criteria established in the FHSR by providing two independent vacuum relief lines. e It is, therefore, concluded that the existing containment isolation system that is required to function during the FHAIC is in compliance with the criteria established in the Hazards Summary Report for engineered safety features. Response 2 The Containment Isolation System (CIS) is the only engineered safety feature system that is required to function to mitigste the radiological consequences i of an FHAIC. An analysis of the NRC Standard Review Plan, NUREG-75/087, has shown that the following current NRC criteria need to be considered regarding ( the Containment Isolation System: 10 CFR Part 50 Appendix A, General Design Criteris, Criterion 23 - O Protect, ion System Failure Modes j l l l l ~..

3 10 CFR Part 50 Appendix A, General Design Criteria, Criterion 56 - Primary Containment isolation Regulatory Guide 1.53, Application of the Single Failure Criterion to Nuclear Power Plant Protection Systems lEEE Standard 379-1977, Standard Application of the Single Failure Criteria to Nuclear Pcwer Generating Station Class IE Systems Criterion 56 -requires that lines connecting directly to the containment atmosphere through the containment be provided with two containment isolation valves, one inside containment, the other outside containment. The criterion further requires that valves outside containment be located as close to the containment as practical and that the automatic isolation vlaves shall be " fail-safe" upon loss of actuating power. The Big Rock Point Plant has two such lines penetrating the containment. They are the air supply and exhaust lines. Ea~ch line has two isolation valves in series (see 0740G40125, Attachment II) that are both located outside of containment, as close to the containnent as practical. The redundant isolation valves are automatically controlled via electric signals controlling air to the pneumatic valve operators. The valve operators are " spring to close" which allow automatic i closure on loss of air and/or electric power. The existing system meets Criterion 56 with the exception of valve location. The remaining criteria concern the single failure and the failure mode. It is required that the components in the CIS have a failure mode that is " fail-safe." It is also required that the redundant valves have control circuitry that meets the single failure criterion. As it applies to this 'csse, the single failure criterion means that containment isolation shall not be prevented due to the failure of any single component in the scheme. (See schemes on Attach =ents III and IV.) Analysis II (Attachment VI) has been performed to provide a single failure analysis of the containment isolation system schemes. The analysis has been performed in accordance with IEEE Standard 379-1977. j l Response 3 As noted in Response 2, the containment isolation system design complies with Criterion 56 except for the location of the isolation valves. The existing l design at Big Rock Point places both isolation valves outside the containment whereas the current criterion requires that one of these valves be located inside containment. The existing isolation valves are located as close to the containment as practical. It is not credible to assume that the conditions inside containment during fuel handling activities could be severe enough to compromise the physical integrity of the ventilation piping between the l g centainment and the first isolation valve. Consumers Power Company, l therefore, considers that the existing valve location design provides adequate assurance that Part 100 limits will not be exceeded as a result of a fuel handling accident inside containment. l

g a 4 (::) ~ Analysis II (Attschment VI) identifies the fact that the existing ventilation isolation system control circuitry does not meet the single failure criteria as established by IEEE Standard 379-1977. The postulated failures that do not meet single failure criteria are " stuck" contacts, mechanical failure of the solenoid valves and " hot shorts." Rasmussen) of a manual switch contset f ailing to transpose is 1x10 p/ demand. The probability of each of these failures is low. The probability er There is also a very low probability that the contsets on a relay will stick or " weld" closed. The probability (per Rasmussen) of the solenoid valve failing to operate is lx10-3/ demand. This probability includes both electrical and mechanical failures. Since this application is concerned only with mechanical failures, and since they are less likely to occur than electrical failures, the probability of mechanical failure is considered extremely low. The probability (per. Rasmussen) of " hot shorts" or shorts to power is 1x10-8/ hour. Three events are necessary in connection with fuel handling in order to exceed Part 100 limits. First, a postulated failure of the ersne is required while moving a fuel transfer cask over the reactor vessel with the head removed. Second, a postulated failure of the safety brake is also required, before the cask could possibly be dropped into the reactor. And third, the postulated failure of one of the ven ilation isolation control valves, for at least v fourteen minutes, is also required. The need for these three events to occur O simultaneously further reduces the probability of exceeding Part 100 limits. As a result of the above analysis, Consumers Power Company considers that it is not necessary to have the containment isolation system meet current NRC . criteria for ESF systems in order to mitigate the radiological consequences of a fuel handling accident inside containment. Response 4 No changes to the existing plant are planned. David A Bixel (Signed) David A Bixel Nuclesr Licensing Administrator CC: JGKeppler, USNRC l 0

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_ _. =- _ ATTACHMENT V o ANALYSIS I System Logic Descriptioa I. Air Supply Valves Logic Description The Logic Diagram for the air supply valves, Scheme 8501, is shown on Sketch No 1, Attachment III. The two series air supply valves (see j 0740G40125, Attachment II) to the containment are labeled CV-4096 and CV-4097. One valve is a butterfly, the other is a check. These are

  • pneumatically operated valves that require air to open but are spring to close. This feature makes the isolation valves " fail-safe" on loss of instrument air.

The CVs can be orened with air from either of two parallel solenoid valves labeled SV-9151 and SV-9152. Air is supplied to these solenoid valves via an instrument air line or a connection to a bank of nitrogen-bottles. Power to the solenoid valves is supplied from 125 V d-c BKR #72-ID26 via parallel contacts SVXI and SVX2. The closure of either of these contacts will ene--ize the SVs, permitting the CVs to open. SVX1 relay () is energized via proper alignment of contacts from the SS (closed l under normal conditions, open during scram), HS 9001 (closed with switch in "open" or " normal after open" position), and SVXS contact (closed on normal radiation levels, open on high). An open contact o'n any one of these devices provides an actuation signal that closes the CVs. The SVX2 relay is energized on a vacuum relief signal which causes the SVX2 contact to close which in turn energizes the solenoid valves and opens the CVs. The relay is energized on increasing vacuum at -1.00 psig and is de-energized on decreasing vacuum at -0.70 psig. The auxiliary relays PISX1/173 and PISX2/173, as shown on 0740G30114, t Attachment I, provide the necessary contacts for the desired deadband and annunciation. l II. Exhaust Vent Valves Logic Description The Logic Diagram for the exhaust vent valves, Scheme 8512, is shown on Sketch No 2, Attachment IV. The logic description is identical to the one above for air supply valves with the e::ception of the appropriate equipment numbers and the auxiliary relays on the vacuum relief scheme. l These relays are not required inasmuch as no additional annunciation it required for this scheme. ~ l oc1178-0378b-43 e

I ATTAC121ENT VI O ~ i ANALYSIS II 1 I. Single Failure Analysis for Air Supply Valves, Schesc 8501 i A basic requirement in the design of a Class IE system is that no sing 1Ie failure of a component will interfere with the proper operation of an independent redundant counterpart or system. The redundant counte rpa rts in this case are the series isolation valves CV-4096 and CV-4097. The point of this an dysis is to determine if these valves will have the proper failure mode in the event of a single failure of a component. At this point it is appropriate to emphasize that the failure mode of the CVs is in the closed position. The closed position is required for containment isolation. The valve operator is air to open and spring to close. Independence and redundancy are the principal means of meeting the single failure criteria. The redundancy and independence of the CVs allows them to meet the single failure criteria as one set of components. Air is supplied to the CVs via parallel solenoid valves, SV-9151 and O SV-9152. The solenoids are energized to supply air to the CVs to maintain them in sa open position. A common type of solenoid failure would involve having a coil wire "open" causing the solenoid to de-energize, thereby allowing the CV to " fail-safe." A less common but credible type of failure would involve a mechanical failure of the core assembly that. prevents the solenoid from cycling to vent the air to the control valve when the tolensid is de-energized. This type of failure would not allow the CV to close. Inasmuch as either SV can supply air to both CVs and either SV is postulated to failure, the single failure criteria is not met at this point. I The effect of interfacing systems on the CIS must also be analyzed for i single failure. The instrument air supply system is one such interfacing system. Inasmuch as air is not required to perform the containment isolation function, the instrument air supply does not have to meet single failure. ~ Relay contact SVX2 will energize the SVs en a high vacuum pressure signsl. Energizing the SVs opens the CVs. Opening the CVs, during this condition only, allows air into the containment. As the vacuum i condition is eliminated the CVs will again close to mitigste the release l of contaminants to the atmosphere. The relsy is normally deacnergized i and cannot be expected to fail electrically. A second type of failure l mode to be considered is when the relsy is energized during a vacuum relief sigual and then the signal is removed. It can be postulated that O. I i , - ~.,.... ,,,,,---.--n .,.u

ATTAC1 RENT VI !O ~ the relay contact could fail closed, thereby allowing the CVs to remain open after'the vacuum is gone. If the contact is postulated to stick + closed the eingle failure criteria is not met. Relay SVX1 is normally energized to close the SVX1 contact which energizes the SVs and allows the CVs to open. The relay is energized through the closed contacts of the SS (Reactor Protection System) HS-9001, and relay SVX5. Opening any of these contsets causes relay SVX1 to de-energize, thereby de-energizing the SVs and closing the CVs. The two postulated failure modet, of the relay SVXI are the same as relay SVX2 above. If the coil fails electrically the contact will open and circuit will " fail-safe." If the contact is postulated to stick closed, the power to the SVs would be maintained and the single failure criteria would not be met for this component.. As with the above contacts, it can be postulated that the contacts for the MS-9001 or SVX5 could fail in a closed position, thereby not permitting the appropriate isolation signal to de-energire SVXI which de-energizes the SVs and allows the CVs to close. However, since thess contacts represent redundant methods of providing the necessary actuation signal, a failure of either would not prevent closure of the isolation valves. The SS signal is provided through two series contacts, thereby providing redundancy and meeting the single failure criteria. The high radiation signal to the SVXS relay is provided thr'ough two series contacts from independent area monitors, thereby providing redundancy and meeting the single failure criteria. The power supply for the isolation scheme is a 125 V d-c breaker. A postulated loss of power would de-energize the SVs and allows the CVs to " fail-safe." Inasmuch as power is not required to provide containment isolation, the single failure criteria for this component is met. In summary, the single failure criteria is not met due to the configuration of the following components: SV-9151, SV-9152, SVX2 contact, and SVXI contact. A failure of either SV to cycle properly could prevent the air to the CV from being vented and the CVs would remain open. A failure of the contacts to open in the remainder of the above components could allow the SVs to remain energized and the CVs would remain open. As, a result of the lack of redundancy in the control wiring to the redundant CVs, it is also necessary to consider a postulated " hot short" in the wiring that could allow the SVs to ecmain or become ener::ized independent of the ventilation isolstion actustion signal. This failure also results in a nonconformance with the single failure criteris. O 2

ATTACle!ENT VI O II. Single Failure Analysis for Exhaust Vent Valves, Scheme 8512 The exact similarity between Schemes 8501 and 8512 would result in an identical analysis for both. Therefore, the analysis for Scheme 8512 will not be separately detailed. III. Conclusions In ' performing a systematic single failure analysis in the format suggested by IEEE Standard 379-1977, the following has been determined: 1. t'he required protective function is containment isolation during a postulated fuel handling accident inside containment. 2. The required protective action is the closure of the containment isolation valves. 3. The closure of the isolation valves is the only system available to provide the protective function. 4. Redundant isolation valves exist in the system, but there is no clearly defined independence or redundancy in the control circuitry that operates the isolation valves. O 5. After conducting a systematic evaluation of potential failures, the single failure criteria is not met for the scheme as a whole. (Several components do, however, meet the single failure criteria separately.) The following assumptions were made in this single failure analysis: 1. There are no identified nondetectable failures inherit to the system j design. 2. The system is qualified to withstand the affects of a seismic event without failure to any of its components. It is, therefore, not required to analyze the system in the presence of event-caused failures and/or identified nondetectable failures coincident to any single failures. O 3

Consumets Q CQ P0',7er M CO 8 ~_L1TED CORRESPO.vDM LLE a.a.,..ome...sinw.. u ....a4... s.e a.ucn.. .eae,.4, c.sivvee.oeao Dece='er 29, 1978 c 4 Director,:Tuclear Reae:cr Regula:1c 8 Att: Mr Dennis L ::ia-en, Chief. Operating Rese:crs 3rasch No 2 i.' CCCYtTE3 ' ~ ~ ~ US Huclear Regulatory Cecissica w Washi:g:ca, :C 20555 MAY 191981

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remy A.,'/ ocC:c-50-155 - 1:ccrsI c?R.a:r,a 3IG 20CI POCT PlA:IT - COU"aI;EIT -a PURG ;G ::URCG 30RMAL PLA3 0?IRATIO3i /. P ' i.__ * \\ ~3 RIS?OOSI TO URC L IIR DATI3 30VIMRER 29, 1978 Your letter dated 3 eve =ber 29, 1978, discussed reces: proble=s involvug purging of reacter centai=ent vessels during nor=al plant cperation. Specifically, you discussed reces; evenu :n vnich safety actuation signals ve== 4- 'vertently overridden when perfor=ing such purging. Your letter requested that power reactor licensees cc--4t to a course of action involving O ter

  • ation of all conta1=ent purging during =cr-*'

plant operation or specific justificatics of the acceptability of such purging. Big Rock Poir; is designed to continucusly ventilate the reactor contai=ent building. Plant design utilizes ccetinuous ventilation to provide ec a '-a-tics ccatrol for access to cperating equipment and cccling to ::,aintain cri-ical equip =en: operable. During vars veather, the ec :inucus ventilatica is essen-tial to =aintain the centai=ent te=perature withi the li=its described in the Final Hazards 5"-

  • y Report for large break accident initial conditices.

During vinter scaths, inlet air =ust be heated to : sic:ain contai=ent te=pera-ture above the icver li=it censidered in the Final Ea:ards 5"--**y Report. Standard Reviev Plan Secticn 6.2.k and 3 ranch Technical Positica CSB 6 k, which vere attached to your letter, appear to address, plants of aever design involving centai=ents nor= ally isolated and for veich contai=ent purging is se abscr- cenditien. 31g Rock Point differs fres this design in that the centai=ent is acr-a'17 ventilated as described in the Final Ra:ards 5"--/ Reper.. An additic al difference is that no reactor protective syste= actus:1cn signal cust be overridden to ope the con-'d--aat isolation valves. ? e isclation valves are presumed to be cpr' at all times and actuatien signals are provided to close them in accident sit u Q ns. Based c: the above censiderations, Censumers Power Cc pany has cene.'.uded tha: the request of your letter concerning li=itation of ccatai=ent purging is inap;repriate for 31g Rock Point. O Tnt P E O P 7 c)o ) o 2 o ) 33

/ z e d Consumers Pever Company vill review 31g Rock Point safety actuation circuits as requested in your letter. S e results of this review vill be provided by mid-March, 1979 David A 31xel (Signed) 1 David A 31xel Nuclear Licensing Admidstrater CC: JGKeppler, USNRC k i O l I ( O t

.. J V f. 0 i a. ',. 3 ", ' /' n atay,% s UMTED STATES ,7..,,* v "M ,o NUCLEAR REGULATORY COMMISSION ,I wAsniscrow.'o. c. rosss ItEt_ TEu corr 2SWDE*'t ~ %,'..M y# o tober l'6,1979 c s Docket No. 50-155 9 CCCY2TED / UST Mr. David Bixel MAY 191981

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,.,. 3. g { j Nuclear Licensing Administrator r-Consumers Power Company .... ::..ta Q f 212 West Michigan Avenue u Jackson, Michigan 49201 D,

Dear Mr. Bixel:

We are continuing our review of your November 29, 1978 subnittal related to fuel handling accidants in containment and your December 28, 1978 submittal related to contairnent purging for the Big Rock Point plant and have found that the additional information described in the enclosure to this letter is needed. We request your response within 45 days of the date of this letter. A generic evaluation of containment purge system electrical design has established certain evaluation criteria. A copy of these criteria are attached for your information. Sincerely, G4 , sm l Dennis L. Ziemann!< Chief Operating Reactors Branch 12 Division of Operating Reactors l l

Enclosure:

1. Request for Additional Information 2. Criteria for Evaluation of Containment Purge System Electrical Design cc w/ enclosures: See next page O gwPEOF 1 c\\ l 03om21

Mr. David Bixel October 16, 1979 cc w/ enclosures: Mr. Paul A. Perry, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Hunton & Williams George C. Freeman, Jr., Esquire P. O. Box 1535 Richmond, Virginia 23212 Peter W. Steketee, Esquire 505 Peoples Building Grand Rapids, Michigan 49503 Charlevoix Public Library 107 Clinton Street Charlevoix, Michigan 49720 Sheldon, Hannon, Roisman and Weiss 1725 I Street, N. W. Suite 506 W'shington, D. C. 20006 a Mr. John O'Neill, II Route 2, Box 44 i l Maple City, Michigan 49664 ^ l l

REQUEST FOR ADDITIONAL INFORMATION BIG ROCK POINT PLAtiT C0flTAlfMENT PURGE SYSTEM DOCKET 50. 50-155 1. In your sutmittal on " additional information relative to fuel handling accident in containment" dated November 29, 1078, you recognized some single failures in electrical design. In addition, because of automatic vacuum relief system circuits being integrated into the containment isolation system, there are several other single failures in the vacuum relief system that could. block an isolation signal. A technical evaluation report was prepared by our consultants EG&G Idaho, Inc., on Big Rock Point plant containment isolation system (CIS). The report has concluded that the lack of redundancy and independence in the air supply and exhaust portion of the containment isolation system and its integrated vacuum relief system, leaves the CIS open to numerous disabling single failures. The staff has reviewed this report and concur in its conclusions. A c,opy of EG&G Report No. RE-A-79-045 is attached. You are requested to address each single failure postulated in the report and provide a justification and/or proposed modification to the CIS. 2. There is only one manual contrm'. switch (HS-9001) to close both air' supply valves and both exhaust valves. In July 16,1973, I&E O Bulletin fio. 73-2 required all licensees to take action to determine whether the failure of a single control switch could result in t.he simultaneous failure of the redundant supply ~ valves or redandant exhaust valves. You are requested to address your response to this tviletin. Attactment: EG&G Report flo. RE-A-79-045 O O O S et

For U. 5.14uclear keguiewry .;,...u :.c. ATTACHMENT I 1 i r CODE ASSESSMENT AND APPLICATIONS PROGRAM i TECHNICAL EVALUATION REPORT BIG ROCK POINT PLANT CONTAINMENT ISOLATION SYST g (Docket 50-155) o. by i C. J. Cleveland 1 l g-e .;.,== + 4~. ~ '4. uwsm i:. ".f ;=,. [I l f-[r 3 s.:= t c:.4 EGrG Idaho. Inc. .. Sf . /.m C .li;;... : K, s

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...-..s... . ~,.... ,..co...,11.. December 3, 1979 4 ', '4 / 000 KITED i Director, Nuclear Rear. tor Regulation {Q,3 i twe Att Mr Dennis L Ziemann, Chief Mg(,1 9198) $ 1 Operating Reactors Branch No 2 , ~\\ US Nuclear Regulatory Connaission \\A 0;.'3d./,D'/ g s y Washington, DC 20555 ',, ** "ify'f " DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - CONTAINMENT PURGE SYSTEM; CONSUMERS P0kT.2 COMPANY RESPONSE FOR ADDITIONAL INFORMATION By letter dated October 16, 1979, the NRC requested addit.ional information regarding our submittals of November 29, 1978 and December 28, 1978 covering fuel handling accidents in containment and containment purging for Big Rock Point Plant. The NRC letter requested that Consumers Power Company address single failure of the Big Rock Point containment isolation system as discussed in the EG&G Report No RE-A-79-045 (which is attached to the October 16, 1976 NRC letter) and provide a justification and/or proposed modification to the containment -isolation system. Consumers Power Company was also requested to address the concern over single manual control switches. If they fail, it co. M result in the simultaneous failure of the redundant supply valves or redundant exhaust valves. Consumers Power Company is currently reviewing proposed design changes to the containment isolation system to alleviate the concerns radsed in the October 16, 1979 NRC letter. Final solution is expected by February 1, 1980 and full details of the solution will be submitted to the NRC on or before this date. David P Hoffman (Signed) David P Hoffman Nuclear Licensing Administrator CC JGKeppler, USERC DQ?E O D se

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  • Area Code S17 788+oS5o March 14, 1980 G

' - M M [ US Nuclear Regulatory Ccmmission gf I/ Operating Reactors Branet No 2 Washington, DC 20555 x DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - CGNTAINME2C PURGE SYSTEM, SINGLE FAILURES Reference 1 provided the NRC staff with a single failure analysis of the existing Big Rock Point Plant Containment Purge System (Ventilation Supply and Exhaust Isolation Valves). The NRC then sent this analysis to EG&G who sub-stantiated our findings. Reference 2 requested Consumrs" Power Company to address each single failure postulated in the EG&G report (attached to Reference 2) and provide a justification and/or proposed modification to the purge system. Reference 3 outlines Consumers Power Company's action and schedule. Reference 1 had already identified the same single failures as pointed out in the EGGG report and each single failure was addressed and justified by a combination of probabilities and equipment redundancies. Since the NRC did not respond to these justifications, and based on Reference 2, Consumers Power Company has redesigned the electrical control schemes for he containment l ventilation supply and exhaust isclation valves. These new schemes are shown on Drawings SK-0740G30114, dated 11-30-79, and $K-0740G40125, dated 11-30-79, and were submitted to the NRC staff for consideration.. The Big Rock Point Plant staff has reviewed these new schemes and found that all of the single failures have been eliminated. l The detailed design phase of this modification has not yet started. However, if delivery time for qualified equipment is not unreasonable, modification t l completion is expected prior to start-up from the next refuelin?, outage 1 (October 24, 1980). l Reference 2 also requested Consumers Power Company to respond to IE Bulletin 73-02 which is concerned with the failure of a r. ingle control switch which could result in the isolation valves failing to operate when required. 3.o th h b\\ bDh ff o 0 3 / 9 O N L> d

.~ 2 l. the single failure analysis submitted in Reference 1 and the single failure analysis prepared by EC&G (Reference 2) showed that the single hand switch does not violate the single failure criteria for this particular control scheme. The failure of this hand switch would not prevent isolation on a high radiation or trip signal nor would it prevent opening the valves for vacuum relief. Therefore, no corrective actions are planned. David P Hoffman (Signed) David P Hoffman Nuclear Licensing Administrator . CC JGKeppler, USNRC

References:

(1) D A Bixel to NRC - letter dated November 29, 1978. (2) NRC to D A Bixel - letter dated October 16, 1979. (3) D P Hoffman to NRC - letter dated December 3, 1979. 1 t i g e O ,.-cm,..,e. --r, ,,.,,w e-..m . - - + -- = ,g}}

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