ML20006E301
| ML20006E301 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/08/1990 |
| From: | Zwolinski J Office of Nuclear Reactor Regulation |
| To: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| Shared Package | |
| ML20006E300 | List: |
| References | |
| NUDOCS 9002220554 | |
| Download: ML20006E301 (7) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
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IN THE MATTER OF Docket No. 50-155 CONSUMERS POWER COMPANY (BIGROCKPOINTPLANT) m m
EXEMPTION I.
Consumers Power Company (CPC, the licensee) is the holder of Facility Operating License No. DPR-6 which authorizes the operation of the Big Rock Point Plant (the facility) at steady-state reactor power levels not in excess-of240megawattsthermal(ratedpower). The fccility consists of one boiling-water reactor located at the licensee's site in Charlevoir. County, Michigan.
The license provides, among other things, that it is subject to all rules, regulations and Orders of the Comission now or hereafter in effect.
II.
Section III.G.I.a of Appendix R to 10 CFR Part 50 specifically requires that one train of systems necessary to achieve and maintain hot shutdown be free of fire damage.
By letter dated October 14, 1986, and supplemented by letters dated February 27, 1987, and February 22,1988, the licensee requested an exemption from the requirements of Section III.G.I.a of Appendix R to 10 CFR Part 50 for having one train of systems necessary to achieve and maintain hot shutdown be
. free.of fire damage.
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Big Rock Point normally utilizes the plant Emergency Condenser (EC) to cool the Primary Coolant System (PCS) which is the preferred method for achieving and maintaining plant hot shutdown, following a fire event in the plant concurrent with~1oss of offsite power.
In the above case, steam flows by convection from the main steam drum to the tube side of the EC.and after its condensation by cooling water on the shell side of the EC, the condensate flows by gravity back to the steam drum. Heat is thus removed from the PCS by the cooling water on the shell side, which vaporizes and is discharged to the atmosphere via the plant stack. Cooling water on the shell side of the EC is sufficient to achieve plant hot shutdown from full power and maintain it for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Makeup coo?ing water to the shell side is supplied before 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> are elapsed by the Demineralized Water (DW) system with the Fire Water (FW) system serving as the backup source, since the DW tank has water for about 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after shutdown. With the above procedures, hot shutdown can be maintained for days or weeks. Cold shutdown is achieved by cooling the PCS in the Shutdown y
p Cooling Heat Exchanger by the Reactor Cooling Water which, in turn, is cooled by theServiceWater(SW)intheReactorCoolingWaterHeatExchanger.
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l The diesel and electric fire water pumps (1 each) and the two SW pumps are all. located in the screenhouse. The SW pumps are separated from the diesel FW i
pump by more than 20 feet and additionally there is an automatic' fire detection system.
However, since there is no automatic fire suppression system in the screenhouse, the licensee has assumed that the worst case fire in the o
screenhouse will result in the unavailability of the diesel FW pump driver, the electric FW pump motor, and both SW pump motors and their power supply cables.
The fire will also affect the delivery of makeup water to the EC, since such I.
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delivery requires two air-operated valves to the EC to be opened. Air to open these valves is supplied by one of three plant instrument air compressors which are normally cooled by SW. Consequently, a severe screenhouse fire will compromise the ability to maintain hot shutdown, as long as it is needed, ar.d the ability to achieve cold shutdown. The licensee has, therefore, proposed a hot shutdown repair to provide the capability to maintain hot shutdown for at least 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> (though the licensee does not intend to maintain it that long) and a cold shutdown repair which can be achieved within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
For the above postulated screenhouse fire, hot shutdown will be achieved by tripping the reactor to control reactivity, and opening the EC outlet valves l
for decay heat removal. Makeup water required for the shell side of the EC 1
after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> will be provided by the DW pump (which is not fire affected) by npening two normal?y closed air-operated valves and establishing a flow path from the pump to the EC. Since both the SW pumps will be unavailable due to fire damage to their motors, the air compressor which supplies air to open these valves will be cooled by the DW system. This will be accomplished by a hot shutdown repair, which involves connecting temporarily an on-site stored cooling water hose from the DW system outlet through a portion of the SW system (where it enters the air compressors cooling system) to the air compressors cooling header; valving in only the air compressor chosen; closing appropriate j
valves to prevent the drainage of DW system to other sections of the SW system, isolating the SW system from the air compressor s; opening a valve in the DW system to permit the flow of DW to the air compressors cooling headers; connecting and starting the standby diesel generator to provide power for the DW pump and the air compressor; and starting the air compressor. The licensee
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states that Chicago fittings have been permanently installed at both ends of the hose, on the SW piping in the vicinity of the air compressors, and on the DW piping to facilitate ease of connecting the hose. The licensee further states that the task will require access to locations outside the screenhouse (ElectricEquipmentRoom(EER)wherethehoseisstoredandtheaircompressors are located, and the machine shop or boiler room adjacent to the EER) and that the entire task will require less than 10 minutes for completion. The repair will be completed before 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
As mentioned above, the DW tank has sufficient water to last for about 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
If water is needed beyond that time, it can be transferred to the DW tank from other on-site water tanks (e.g., condensate storage tank, waste receivertanks). The licensee has determined by analysis that with the above arrangement (coolingwatersupplyfromtheDWtanktotheaircompressorviaa temporarily connected hose and to the shell side of the EC and starting air compressor) and with credit from other on-site tanks, hot shutdown can be maintained for at least 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The operating procedures additionally include instructions to call the Charlevoix Fire Department to furnish a truck with raw water-to fill the DW tank if makeup water is required beyond 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
Regarding the repair for achieving cold shutdown, the licensee stated that during the time available for such a repair, the damaged motor of one of the SW pumps will be removed; the on-site stored spare motor will be transported to the intake structure by crane truck, fork lift or pickup truck, delivered through the truck door to the intake structure, and transported to the SW pump by the manually powered overhead crane in the screenhouse; the spare motor will be bolted to the SW pump casing; the shaft will be bolted to the pump coupling; and n.,_____xn__._- _ _. _ _ _ - _ _. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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i the electrical connection (onsite power cable from the onsite emergency diesel
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generator) will consist of bolted lugs wrapped with tape.
The licensee had performed an analysis (July 1,1986, submittal) which demonstrated that the overhead crane in the screenhouse and the SW pumps will survive the screenhouse fire.
The licensee states the entire replacement task can be accomplished by three maintenance personnel and that it will take less than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to complete.
The licensee has determined that with one SW pump made available in the above manner, cold shutdown can be achieved within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the pump becomes operational. The licensee also states that the spare motor is stored on-site in an accessible location and that it will be inspected at regular intervals as part of the plant inspection program, The possible need for additional fuel to the diesel generators from off-site sources due to postulated loss of off-site power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> has been identified.
l as an open item in a Fire Inspection Report for Big Rock Point (Inspection Report No. 50-155/88-06 Details - Item 2.C).
Regarding the above, in a telephone conversation with the staff on June 30, 1988, the licensee stated that they do not anticipate any such need.
However, should it arise, they can secure the needed fuel from off-site sources within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of their request.
In the above telephone conversation, the licensee also committed to revise the Emergency Operating Procedures EMP-3.10-Fire, Appendix IV - Severe Screenhouse Fire, as suggested in the Inspection Report mentioned above (specific items are listed under 7.c of the Inspection Report - Details).
Based on the above, the staff has determined that the proposed repairs are feasible and that sufficient margins in time will be available for completing them in a timely manner.
The staff has further determined that the proposed u - ~.------
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cold shutdown repair can be completed 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, Item III.G.1.b.
The staff has also determined that with the proposed repairs completed in a timely manner, cold shutdown following a severe screenhouse fire can be achieved within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with or without off-site power.
III.
Accordingly, the Commission has determined that pursuant to 10 CFR 50.12(a),
that (1) the exemption as described in Section II is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security, and (ii) special circumstances are present for the exemption in that application of the regulation in this particular circumstance is not necessary to achieve the underlying purpose of Appendix R to 10 CFR Part 50.
Specifically, the underlying purpose of Appendix R,Section III.G.1.a is to assure that a suitable complement of safe-shutdown equipment will be available, post-fire, to achieve and maintain hot shutdown of the l
reactor. By implementing the hot.and cold shutdown repairs, the licensee meets 1
l the intent of this rule.
The Commission hereby grants an exemption from the requirements of Section
.III.G.I.a of Appendix R to 10 CFR Part 50 to allow a hot shutdown repair to maintain hot shutdown following a worst case fire in the plant screenhouse.
Pursuant to 10 CFR 51.32, the Commission has determined that the issuance of the exemption will have no significant impact on the environment (55 FR 1742 January 18,1990).
l The licensee's request dated October 14, 1986, and supplemented by letters dated February 27, 1987, and February 22, 1988, are available for l
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g 7-public inspection at the Commission's Public Document Room, 2120 L Street, l
N.W., Washington, D.C. and at the North Central Michigan College, 1515 Howard Street, Petoskey, Michigan.
This Exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMM SSION g
John A Zwolinski, Acting Director Divisi of Reactor Projects - III
.IV, V & Special Projects Office of Nuclear Reactor Regulation 3
Dated at Rockville, Maryland, this 8th day of February 1990.
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