ML20039A031
| ML20039A031 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 12/10/1981 |
| From: | Vincent R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-09-03, TASK-9-3, TASK-RR NUDOCS 8112160157 | |
| Download: ML20039A031 (10) | |
Text
4 Consumers Power Company General Offices: 212 West Michagen Avenue, Jackson, MI 40201 *(517) 788-o650 December 10, 1981
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Director, Nuclear Reactor Regulation 5((Tffp.\\/
Att Mr Dennis M Crutchfield, Chief
- Operating Reactors Branch No 5 US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
SEP TOPIC IX-3, STATION SEhVICE AND COOLING WATER SYSTEMS Attached is the Consumers Power Company evaluation of SEP Topic IX-3 for the Big Rock Point Plant.
MT UP-Robert A Vincent Staff Licensing Engineeer CC Director, Region III, USNRC NRC Resident Inspector-Big Rock Point j'- 035 s
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oc1281-0010a142 8112160157 811210' PDR ADOCK 05000155 P
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s SEP REVIEW OF STATION SERVICE AND COOLING WATER SYSTEMS TOPIC IX-3
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BIG ROCK POINT NUCLEAR PLAIE i
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INTRODUCTION The safety ' objective of Topic 'IX-3 is to assure that cooling water systems have the. capability, with adequate margin,. to meet design objectives and, in particular to assure that:
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'A.
Systems are provided vith adequate physical separation such that there-are no adverse interactions among those systems under.any mode of operation; TB.
Sufficient cooling water-inventory has been provided or that
~ dequate provisions for make-up are available; a
C.
Tank overflow cannot be released to the environment without-monitoring and unless the level of radioactivity is within acceptable limits;
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D.
Vital equipment necessary for achieving a controlled and safe.
shutdown is not flooded due to failure of the main condenser circulating water system..
II.
REVIEW CRITERIA The current criteria and guidelines used to determine if the plant systems
" meet the topic safety objectives are those provided in Standard Review Plan (SRP) Sections 9 2.1, " Station Service Water System", and 9.2.2,
" Reactor Auxiliary Cooling Water Systems".
III. RELATED SAFETY TOPICS AND INTERFACES The scope of review for this topic was limited.to avoid duplication of effort.since some aspects of the review were performed under related topics.
The related topics and subject matter are identified below. Each of the relat2d topic reports contains the acceptance criteria and review guidance for its subject matter.
II-2.A Severe Weather Phenomena II-3.B Flooding Potential and Protection Requirements II-3.B.1 Design Basis Flooding II-3.C Safety-Related Water Supply III-3.A Effects of High Water Level on Structures III-3.B Flooding of Equipment -(Failure of Underdrain System)
III-3.C Inservice Inspection of Water Control Structures III-k.A-Tornado Missiles III-4.C Internally Generated Missiles III-5.A HELB Inside Containment t
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-III-5.3 HELB Outside Containment III-6 Seisn.c Design Considerations d
III-12' Environmental Qualification of Safety-Related Equipment -
VI-2.D Mass'and Energy Releases VI-7.A.3 -ECCS Actuation Systems VI-7.C ECCS Single-Failure Criterion VI-T.C.1 ' Independence of On-Site Power VI-T.C.2 ECCS Failure Mode Analysis VI-T.D Long-Term Cooling Passive Failures VI-7.E ECCS Sump Design and Test for-Recirculation Mode Effectiveness VII-3 Systems Required for Safe. Shutdown l
VIII-2 On-Site Emergency Power Systems - Diesel Generator IX-1 Fuel Storage IX-6 Fire Protection The following topics.are dependent on the present topic information for completion:
l VI-3 Containment Pressure and Heat Removal Capability f-
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V-5 Reactor Coolant Pressure Boundary Leakage Detection
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IV.
REVIEW GUIDELINES i
l-In addition.to the guidelines of SRP Sections 9.2.1 and 9 2.2, in determining i
which systems to evaluate under this topic the staff used the definitions of.
" systems important to safety" provided in Reference A.
The definition states systems important to safety are those necessary to ensure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the reactor and maintain it in a safe condition or (3) the capability to prevent or mitigate the consequences of accidents that could l
result in potential off-site exposures comparable to the guidelines of j
10CFR100, " Reactor Site ' Criteria". This definition was used to determine I
which systems or port _ons of systems were " essential". Systems or portions l
of systems which perform functions important to safety were considered to be essential. It should be noted that this topic will be updated if future SEP reviews identify additional-cooling water syste=s that are important to safety.
V.
EVALUATION i
The systems reviewed under this topic are the Service Water System, Reactor l
Cooling Water System, Demineralized Water System and the Fire Protection l
System. The Spent Fuel Pool Cooling System is discussed in the SEP review of Topic IX-1, " Fuel Storage".
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.A.--SERVICE WATER SYSTEM The Service Water System (SWS) takes its supply from Lake Michigan to provide _the cooling. vater services in the turbine building, service building and the reactor building.
- The -system consists of two vertical turbine type centrifugal pumps, piping,. instrumentation and controls. The pumps, each having a cap-1acity of 2100 gpm, take their suction from the center of the intake structure. One pump supplies the normal needs of the service water
, system.
The pumps are povered from h80 volt Motor Control Center 1C and 2C.
~The two pumps' discharge into a common header which supplies cooling water to the following heat loads:
1.
~ Generator Hydrogen Coolers (h) 2.
Turbine Lube Oil Coolers'(2) 3.
Reactor Feed Pump Lube Oil Coolers (2) h.
Turbine Building and Reactor Building Air Coolers
.5.- Air Compressor Jackets and Aftercoolers (3) 6.
Chlorinator 7
Condenser Circulating Water Pump Seals (2) l 8.
Turbine Bypass Valve Oil Cooler (1) 9 Condenser vacuum Pump Seals (1) 10.
Heating Boiler Blowdown 11.
Miscellaneous Washdown Connections 12.
Reactor Cooling Water Heat Exchangers (2)
During normal operation, the majority of the above listed heat loads on the service water system are in operation.
A manually operated cross-connect valve between the fire protection system and the SWS, located in containment, is provided to assure the availability of cooling water to the reactor cooling water heat ex-changers in the event that the service water system fails. A check valve in the service water supply piping to the reactor cooling water heat exchangers will prevent fire system flow back through the service water header to any of the other equipment in the tm-bine building serviced by the SWS.
The manual valve is normall3 lt:ked closed.
Since the service water discharge from the reactor cooling water heat exchangers is potentially radioactive (due to possible tube leaks), the discharge water is monitored continuously through a liquid process
, monitor (RE-8273) prior to exiting containment and mixing with condenser circulating water going to the discharge canal.
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[h If total _ loss of service water occurs during normal plant operation,
- inmediate operatorf actions' are.to scram the reactor and to open the
' service vater-fire water cross-connect _-valve to permit continued operation of the reactor. recirculating water pumps. This action vould-
-also allov. continued use of the reactor cooling water system. Section B (Reactor Cooling Water System), below discusses cooling loads ser-viced by the reactor cooling water system.
No credit is taken for the SWS for mitigating the consequences of a-los s-o f-coolaat-accident.
Based on our review of the Service Water System (subject to the 'finda ings of the additional SEP reviews noted above), we have determined -
that the service water system is not important to safety as defined in Reference A.
B.
REACTOR COOLING WATER SYSTEM
-The. Reactor Cooling Water System (RCW), provides cooling water to the.
reactor shield cooling panels and other radioactive _ cooling systems.
Since it is potentially radioactive (due to tube leaks), it is f contained in a _ closed loop independent of the Service Water System and located inside containment.
For normal plant operation, one RCW pump and heat exchanger are placed in service. The RCW system is composed of the following equipment:
A concrete tank of approximately 5300 gallons, two ft11 capacity vertical fcur-stage pumps with a capacity of 1500 gpm eac two full capacity heat exchangers with a design capacity of 9 x 10g, Btu /hr each, piping, level indication, pressure controls, radiation detection devices, valves and associated equipment to and from the various equipment serviced by the RCW system.
The pumps are povered by h80 volt Motor Control Centers 1A and 2A.
The RCW pumps discharge into a common header which supplies cooling water to the following heat loads:
1.
Reactor Recirculating Pump Coolers (2) 2.
Shutdown Cooling Pump Gland Coolers (2) 3 Non-regenerative Heat Exchanger (1) h.
Fuel Pool Heat Exchangers (2) 5 Shutdown Heat Exchangers (2) 6.
Reactor Shield Cooling Panels (8)
The reactor shield cooling panels receive water from the RCW pump discharf;e header; the water cools the panels and flows directly back to the reactor cooling water tank.
As any leakage from the reactor cooling water is potentially radioactive, the system is designed to operate at a lower pressure than the service water system'where the systems interface at the ECW heat exchangers.
Reactor cooling water flowing to the RCW heat exchangers is continuously
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monitored through a liquid process monitor (RE-8272). An additional liquid process monitor (RE-8273) is provided on the service water discharge as it exits containment. The cooling water is inhibited demineralized water for prevention.of corrosion. In the event that a leak to the containment sumps develops in the.RCW system, the operator vill receive a lov RCW tank level alarm. The system is provided with a make-up supply to the RCW tank from the demineralized water system.
The most likely cause of a total loss of the RCW system is a loss of
-station power. The operator is instructed to connect one RCW pump to the emergency 2B bus supplied by the emergency diesel generator if load conditions permit. The RCW heat exchangers can be cooled by.
providing fire water to the heat exchanger tube side in lieu of service
-vater.
If loss of station power is not the cause of, the loss of the RCW system and it is not possible to start a_ RCW pump, the operator is -
instructed to scram the reactor, stop the recirculating water pumps and isolate one recirculating water loop. Isolation of one loop provides positive protection of the pump seals on one of the two recirculating water pumps from overheating and still allows for natural circulation l'
through the unisolated loop. The effects of loss of alternating current power on pump seals is currently being investigated as part of NUREG 0737; Item II.k.3.25 The reactor could then be cooled by the emergency condenser system. The emergency condenser is provided with cooling
-vater from the fire system or the demineralized water system.
i No credit is taken for operation of the RCW system for mitigating the l
consequences of a loss-of-coolant-accident.
Based on our review of the Reactor Cooling Water System (subject to l.
the findings of additional SEP reviews noted above), we have determined L
that the RCW system is not important to safety as defined in Reference A.
C.
DEMINERALIZED WATER SYSTEM l
l Although no credit is taken for the Demineralized Water System (DMW) in mitigating the consequences of a loss-of-coolant-accident, it is being considered here because it is a source of make-up water to the l
Reactor' Cooling Water supply tank and the Emergency Condenser which may j
be used for plant cooldown.
l Upon the loss of the normal heat sink and/or loss of station power, the Emergency Condenser is used to cool the primary system.
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contained in the shell side of the Emergency Condenser is sufficient
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for approximately four hours without make-up. The Demineralized Water System or the fire system can be used for make-up water to the Emergency l
Condenser if required.
As explained in B. 'above, the DMW system is used, as required, to make up water to the RCW system.
The DMW feed pump is driven by a h80 volt, 7.5 hp motor supplied by motor control center 1C.
The pump takes its suction from a 5000 gallon demineralized water storage tank. Make-up water is automatically supplied to the Energency Condenser when required to maintain a proper level.
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'Make-up' vater to the-RCW nupply. tank requires manual ~ action which is initiated by an; operator upon receipt of' a low-level alarm in the
. control room.
- During'a loss-of-coolant-accident, neither the Emergency Condenser nor the RCW system is required; therefore, the DMW system is not required.
Based on our review of the I2GI system (subject to findings of the
- additional SEP reviews noted above), we have determined that the DKW
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system is not important to safety as defined in Reference A.
D.
FIRE' PROTECTION SYSTEM The Fire Protection System (FPS) is discussed under this SEP topic because of its' role in providing back-up cooling water supply to the '
emergency condenser, the RCW heat exchangers and in providing the nec-essary water supply to the core spray heat exchanger, which 'is.part of the post-incident (ECCS). system. While the role of the FPS in mitigating the consequences of a loss-of-coolant-accident is discussed here in general terms, more specific and detailed information on the Emergency Core Cooling System (ECCS) can be found in other SEP topics listed in Section III of.this document.
The FPS contains three fire pumps; jockey, electric and diesel. These pumps take their suction from the condenser circulating water intake structure and discharge into the fire system header. The fire system
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header exits the screenhouse, where the pumps are located, as a single -
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underground pipe that connects to an underground yard loop that circles the containment, turbine and service buildings. Fire water enters l
the containment either through the turbine building pipe tunnel or, as a back-up, through the core spray pump and heat exchanger room.
In-l side containment, 'the fire protection system provides cooling or' spray water to the following equipment:
1.
RCW Heat Exchangers (in lieu of service water) 2.
Emergency Condenser Make-up (in lieu of demineralized water) 3 Primary Core Spray 4.
Redundant Core Spray 5
Primary Containment Spray 6.
Redundant Containment Spray 7
Fire Protection A separate fire header runs from the underground yard loop to the core spray pump and heat exchanger room. This fire header provides a redun-dant path for providing cooling or spray water to the above equipment.
In addition, this line provides cooling vater to the shell side of the core spray heat exchanger. A fire hose is located in the screenhouse that can be used to provide cooling water to the core spray. heat exchanger in the event that the single header connecting the screenhouse to the underground yard loop fails. Operators.vould be required to attach
T this hose.to a hose manifold outside the screenhouse and to a hose connection on the core spray heat exchanger.
The hose is dedicated for this purpose only.
In addition to the piping described above, the main components of the fire protection system are the accumulator, jockey fire pump, diesel fire pump, electric fire pump.
The fire system accumulator is a 670-gallon tank located in the screen-house.
It provides a reserve water supply and pressure head for the system. The jockey fire pump is a vertical turbine pump driven by a 3 hp, 480 Vac motor powered from MCC-2C.
The jockey pu=p starts when the system pressure drops to 80 psig to maintain the proper level in the accumulator tank. Both the electric and diesel-driven pumps are vertical, four-stage, turbine type pumps having a capacity of 1000 gpm at 100 psig. The driver for the electric pump is a h80 Vac, 100 hp motor.
The motor is powered from emergency bus MCC-2B which is connected to the emergency diesel generator. The driver for the diesel-driven pump is a six-cylinder,103 hp,1750 rpm diesel engine. The electric driven pump automatically starts when system pressure drops to 70 psig and the diesel-driven pump automatically starts when pressure drops to 60 psig. Both pumps are automatically started upon receipt of a signal from the Reactor Depressurizing System in order to assure avail-ability of core and containment spray water prior to depressurizing the reactor coolant system.
During the post-accident recirculation mode, water is drawn from the containment sump, cooled by the core spray heat exchanger and returned to the core spray header. The recirculation mode starts between h and 21 hours2.430556e-4 days <br />0.00583 hours <br />3.472222e-5 weeks <br />7.9905e-6 months <br /> after the accident, depending upon the rate of water ad-ditiontothecontainmentthroughthecoreandcontainmentsprags.
The core spray heat exchanger has a heat removal rate of 8 X 10 Stu/
The decay heat generated, assuming reactor power was at 2h0 Mw'5 hr.
6 Btu /hr at h hours and 5.6 X 10 prior to the incident, is 8.19 x 10 Btu /hr at 21 hours2.430556e-4 days <br />0.00583 hours <br />3.472222e-5 weeks <br />7.9905e-6 months <br />. The Post-Incident System capabilities will be discussed in greater detail in other SEP topics.
In the event that the condenser circulating water system piping ruptures,
it is possible that a portion of the screenhouse can become flooded, jeopardizing the operation of both the diesel and electric fire pumps.
The initiating event postulated to cause such a piping failure is the seismic event. The source of water for flooding is that volume of water contained in the two 36-inch lines that supply water to the condenser that could drain into the screenhouse. There are two 3-inch floor drains in the screenhouse which may be adequate to prevent flood-ing if the flooding rate is small. In other words, the pipe break is small or the pipes break in the screenhouse only.
(In order to get rapid drainage of the lines, a break must also occur near the condenser to allow entry of air. ) SEP Topic III-6 will consider the acceptability of the condenser circulating water piping to withstand the seismic event.
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l VI.
CONCLUSION Based on our review of the service and cooling water systems for Big Rock Point, the installed systems and their functions are su=marized as follows:
SWS: Cooling for' the RCW heat exchangers.
RCW:
(1) Reactor shield panel cooling.
(2) Reactor recirculating. pump coolers.
(3) Shutdown heat exchangers.
(4) Shutdown cooling pump gland coolers.
DMW:
(1) Make-up water to emergency condenser.
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(2) Make-up water to RCW tank.
FPS:
(1) Cooling to core spray heat exchanger.
-(2) Alternate cooling water to RCW heat exchangers.
(3) Alternate make-up water supply to emergency condenser.
(h) Core spray, (5) Containment spray.
Of the installed systems, only the Fire Protection System is considered essential and within the scope of this topic. Because this system is the ECCS system for Big Rock, however,. it is more appropriately addressed under other SEP topics such as VI-7. A.3, VI-7.C and VII-2.
No further consideration, therefore, vill be given to this system in Topic IX-3.
VII. REFERENCES A.
Regulatory Guide 1.105, " Instrument Setpoints" B.
Consu=ers Power Company Big Rock Point Plant Final Hazards Summary Report.
C.
NUREG 0737 D.
SRP 9.2.1, " Station Service Water System", Revision 1 E.
SRP 9.2.2, " Reactor Auxiliary Cooling Water Systems :,11/2h/75 k