ML20041F194
| ML20041F194 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 03/09/1982 |
| From: | Linder F DAIRYLAND POWER COOPERATIVE |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TASK-09-05, TASK-9-5, TASK-RR LAC-8144, NUDOCS 8203160280 | |
| Download: ML20041F194 (9) | |
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OlDA/RYLAND h
[k COOPERA7/VE PO BOX 817
- 2615 EAST AV SOUTH. LA CROSSE. W1SCONSIN S4601 (608) 788-4000 March 9, 1982 In reply, please refer to LAC-8144 DOCKET NO. 50-409 U. S. Nuclear Regulatory Commission ATTN: Mr. Darrell G. Eisenhut, Director co cr>
Division of Licensing
.g Office of Nuclear Reactor Regulation
(-
Division of Operating Reactors g ~7.,,.,,.,
s '. s Washington, D. C.
20555 9
O fW'1619323
SUBJECT:
DAIRYLAND POWER COOPERATIVE n n mf.
LA CROSSE BOILING WATER REACTOR (LACBW N f"',
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PROVISIONAL OPERATING LICENSE N0. DPR-4 SEP TOPIC IX-5 VENTILATION SYSTEMS DPC Letter, LAC-7387, Linder to EisenhuC~'3,, '
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REFERENCE:
(1) dated February 27, 1981 Gentlemen:
Enclosed find Safety Evaluation Report (SER) for SEP Topic IX-5, " Ventilation Sy stems,"
which has been prepared for the La Crosse Boiling Water Reactor.
Our letter, Reference 1, identified topics for DPC to submit for NRC evaluation. The subject topics were listed in the schedule submitted with Reference 1.
If there are any questions regarding this letter, please contact us.
Very truly yours, DAIRYLAND POWER COOPERATIVE d
Frank Linder, General Manager FL:LSG:eme cc:
J. G. Keppler, Regional Director, NRC-DR0 III gg NRC Resident Inspector j
li WP1 8203160280 820309 PDR ADOCK 05000409 P
LA CROSSE BOILING WATER REACTOR SYSTEMATIC EVALUATION PROGRAM SAFETY EVALUATION REPORT TOPIC IX-5 VENTILATION SYSTEMS I.
INTRODUCTION The purpose of this topic is to review plant ventilation systems to assure that a safe environment exists for plant personnel during normal operation and anticipated transients and that the functional ability of systems required for safe shutdown of the facility, accident mitigation, or whose failure could result in a significant release of radioactivity is not degraded by the worst anticipated ventilation system performance.
Operation of ventilation systems is examined to ensure that a single active failure of a ventilation system cannot result in loss of the system functional perfor,aance capabilities that would adversely affect the ability to conduct a safe shutdown of the plant or mitigate an accident, or would result in a significant release of radioactivity.
II. REVIEW CRITERIA The following Standard Review Plans (SRP) were used as guidelines in determining whether the safety objective of this topic was met:
(1) SRP 9.4.2, " Spent Fuel Pool Area Ventilation Systs#'
(2)
SRP 9.4.3, " Auxiliary and Radwaste Area Ventilation Systen" (3) SRP 9.4.4, " Turbine Area Ventilation Systs#'
(4) SRP 9.4.5, " Engineered Safety Feature Ventilation Systed' 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 review specifically excluded the following:
(1)
SEP VI-8, " Control Room Habitability" (2) TMI III.D.3.4, " Control Room Habitability" (3) SEP III-4.C, " Internally Generated Missiles" (4) SEP III-12, " Environmental Qualification of Safety Related Equipment" WP1
-1
(5) SEP VI-4, " Containment Isolatlan Systen" (6) SEP XV-20, " Radiological Consequences of Fuel Damaging Accidents Inside and Outside Containment" IV. REVIEW GUIDELINES The following ventilation systems servicing the listed systems needed to perfona safety funcitons, i.e., safe plant shutdown or accident mitigation, or whose failure may result in release of unacceptable amounts of radioactivity, were examined.
A.
Containment Building Ventilation Systen (1) Containnent Building and Containment Isolation Systems (2) High Pressure Core Spray System (3) Manual Depressurization System (4) Control Rod Drive System (5) Reactor Building Motor Control Center lA (6) Boron Injection System (7) Fuel Elenent Storage Well System I
(8) Retention Tanks
- (9) Shutdown Contenser B.
Diesel Building Ventilation System (1) 1B Emergency Diesel Generator (2) Diesel Building Battery (3) 1B Static Inverter i
(4) Diesel Building Motor Control Center (5) 1B 480V Essential Bus.
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- These systems are being considered for upgrade to safety status.
WP1...
C.
Turbine Building Ventilation Systems (1) 1A 480V Essential Bus (2) Waste Water Systen 1
(3) Gaseous Waste System t
- (4) Component Cooling Water System D.
Control Roan and Electrical Equipment Room Ventilation System (1)
Turbine Building Motor Control Center 1A (2) Reactor Plant and Generator Plant Batteries (3) Safety Systems E.
1A Emergency Diesel Generator Ventilation F.
Alternate Core Spray System Ventilation V.
REVIEW AND EVALUATION A.
Containment Building Ventilation System The Containment Building ventilation system utilizes two 30-ton, 12,000-cfm air conditioning units for drawing fresh air into the building and for circulating the air throughout the building.
The air enters the Reactor Building through two 20-inch isolation dsmpers in series, and is exhausted from the building by a centrifugal exhaust fan which has a capacity of 6000 cfm at 4 inches of water static pressure. Approximately 19,000 cfm are recirculated throughout the building.
The system is designed to maintain an inside Summer temperature of 78 F with an outside temperature of 95 F and to maintain an inside winter temperature of 70 F with an outside tenperature of -24 F.
The air conditioning units are completely autonatic, temperature controlled, and designed to meet the summer and winter requirements at 4
the design recirculation flow of approximately 19,000 cfm.
The exhaust fan draws air from the two forced circulation pump cavities. A normally-closed manually-operated damper is provided for an intake duct used for exhausting 1000 cfm of air from the upper portion of the Reactor Building (elevation 745 ft. 3 in.) in the event of high airborne activity in the upper portion of the Reactor Building. A 4-inch vent header, routed from the upper and lower-
- These systems are being considered for upgrade to safety status.
WP1...
reactor cavities, retention tanks, seal inject reservoir, shield cooling surge tank, and from the fuel storage well, vents to the exhaust fan inlet upstream of the exhaust system filters, is also exhausted by this system during normal operation. The exhaust fan discharges through two 20-inch isolation dampers in series to the tunnel.
A 20-inch damper is also provided for recirculation of the exhaust fan discharge air.
The exhaust system is provided with conventional and high-efficiency filters and with a gaseous and particulate radiation monitor system.
In the event high radioactivity is detected by any of the three exhaust system radiation monitors, the two 20-inch air intake isolation dampers and the two 20-inch exhaust dampers are automatically closed; the 20-inch exhaust system recirculation damper is automatically opened; and the flow from the reactor cavities and fuel storage well is automatically diverted from the exhaust system inlet to the 4-inch vent header which discharges at the stack inlet plenum.
High Containment Building pressure, high reactor pressure, and low reactor water level will also close the inlet and outlet dampers, open the recirculation dampers, and shift the reactor cavity and storage well vents to the 4-inch header.
In addition, all four conditions isolate the 4-inch header by automatically closing the internal vent header discharge valve, thus completely isolating the building automatically. Reset buttons in the Control Room are provided to reset the close signal.
The isolation features of the Containnent Building Ventilation System are needed to mitigate the consequences of some analyzed accidents.
Containment isolation capabilities have been previously addressed in SEP Topic VI-4, in the response to IE Bulletin 79-08 (DPC Letter, Linder to Shea, LAC-6732, dated January 14,1981) and in the NRC review of the DPC response to IEB No. 79-08 (NRC Letter, Crutchfield to Linder, dated June 11,1981).
The isolation capabilities of the Containment Building Ventilation System will therefore not be further discussed here.
The High Pressure Core Spray System, Manual Depressuri7ation System, Control Rod Drive System, Boron Inject System, Reactor Building Motor Control Center (MCC) 1A, Fuel Element Storage Well, Retention Tanks, and Shutdown Condenser are situated inside the Containment Building.
Failure of the ventilation system will not prevent any of these systems from performing their functions. Experience has demonstrated that equipment inside containment functions properly when inlet and outlet ventilation dampers are closed, though this is not a desired mode of operation. The isolation features of the Containment Building Ventilation System would prevent release of excessive amounts of radioactivity due to an accident involving the Fuel Element Storage Well (SEP Topic XV-20) or the Retention Tanks.
WP1 No modificaticr. to the Containment Building Ventilation System is warranted, sint.e no single failure of the ventilation sy: tem would prevent operation of any of the above systems in the Containment Building whic',i are needed for safe plant shutdown, to mitigate the consequences of an accident, or whose failure could result in release of unacceptable amounts of radioactivity.
B.
Diesel Building Ventilation System The Diesel Building is divided into three separate rooms; the generator room, the electrical equipment room, housing the Diesel Building MCC, the IB Static Inverter, and the IB 480V Essential Bus and the battery room. The generator room is provided with two motor operated inlet louvers and the two roof ventilator fans with respective solenoid operated exhaust louvers. The whole system has been electrically divided into two divisions, each division consisting of one inlet louver, one exhaust louver, and associated roof ventilator fan motor. Each division can be operated independently of one another.
In each division, interlocks have been provided to ensure start of the ventilator fan motor only af ter the inlet / exhaust louvers are fully open. Control switches are provided for test of the louvers and their respective ventilator fan motors.
With the rise of temperature detected by thermostats located in the generator room, the following sequence of operation is initiated:
(1)
Inlet and exhaust louvers of first division open; (2)
Inlet and exhaust louvers of second division open; (3)
Roof ventilator fan motor of first division starts; and (4) Roof ventilation fan motor of second division starts.
A control switch has been provided at the Diesel Building Motor Control Center to change the sequence of operation between the two roof ventilator fan motors to conpensate for mechanical wear.
The electrical equipment room is provided with two motor operated inlet louvers with associated inlet supply fans and a common motor operated exhaust louver.
These louvers and fan motors are sequenced and operated with rising temperature. A control switch located at the Diesel Building Motor Control Center interchanges the sequence of the two supply fans. Test switches have been provided at the Diesel Building AC Motor Control Center to run individual fan motors with all three louvers open.
Interlocks ensure the operation of each supply fan motor with all three louvers fully open.
The generator roan is provided with an exhaust fan supplied with 120-V AC Power supply from the distribution panel in the Diesel Building Motor Control Center. The battery roon is also provided with an exhaust fan supplied with 120-V AC from the Diesel Building AC Motor Control Center distribution panel.
This fan is designed for continuous use.
ypy -.
Two air conditioners located in the battery room start one af ter another with the rising temperature sensed by the thennostat located in the battery room. A selector switch located in the Diesel Building Motor Control center allows the air conditioners to be sequenced to compensate for mechanical wear.
Five unit heaters in the Diesel Building are automatically controlled by the thermostats and contactors located in individual unit heaters.
The unit heaters are supplied power from the Diesel Building Motor Control Center.
All ventilation equipment in the Diesel Building is powered from the Diesel Building MCC, which is supplied by the IB 480-V Essential Bus.
Upon loss of power, the IB 480-V Essential Bus is fed by the IB Emergency Diesel Generator.
If the IB EDG failed to start during a loss of power event, and so did not supply the Diesel Building MCC, neither the generator room, Diesel Building MCC, or the IB Essential Bus, would require ventilation. Even if failure of the ventilation system adversely affected the IB EDG there would be no effect on the 1A EDG, since it is located in a different building.
If the Diesel Building Battery failed due to lack of ventilation, the other two sources of 125-V DC power would be unaffected, since they are located in the Turbine Building Electrical Equipment Room.
If the 18 Static Inverter failed due to ventilation system failure, the 1B Non-Interruptible Bus, which the IB Static Inverter feeds, could be suppled by its alternate feed, the 120-V Regulated Bus, which is i
powered from the 1A Essential Bus via Turbine Building MCC 1A.
Therefore, even if failure of the Diesel Building Ventilation System affects the equipment in the Diesel Building, it will not prevent safe shutdown of the plant or mitigation of the consequences of an accident.
The Diesel Building Ventilation System has performed reliably since the Diesel Building was built.
C.
Turbine Building Ventilation Systens The Turbine Building Ventilation System services components within the Turbine Building, including the 1A 480-V Essential Bus, Waste Water Systen, Gaseous Waste Systen and Component Cooling Water System.
A loss of station power would result in failure of the Turbine Building Ventilation System.
The Turbine Building Ventilation System (TBVS) does not have any isolation features, therefore its failure could not cause release of excessive amounts of radioactivity, though the release path of radioactivity in the Turbine Building may be redirected without the ventilation system operating. The exhaust for the TBVS is through the ventilation stack, which also serves the Reactor Building, Waste Disposal Building and the gaseous waste system.
Failure of the TBVS will not affect the integrity of the Waste Water System or Gaseous Waste System, and therefore would not result in release of excess amounts of radioactivity to the atmosphere from either of these systems.
Neither the 1A 480-V Essential Bus, nor the WP1 Component Cooling Water System have been adversely affected by failure of the TBVS during actual loss of power events.
Therefore, it is unlikely a future potential failure of the TBVS will prevent either of these systems from fulfilling their functions.. Even if the 1A 480-V Essential Bus did fail due to loss of the TBVS, the IB 480-V Essential Bus would be unaffected, since it is serviced by the Diesel Building Ventilation System.
Based on the above evaluation, it is concluded that the the Turbine Building Ventilation System as installed is acceptable for the La Crosse Boiling Water Reactor.
D.
Control Room and Electrical Equipment Room Ventilation System The Control Room Ventilation System has previously been examined from the standpoint of habitability under TMI Iten III.D.3.4, " Control Room Habi tabi l i ty."
The Turbine Building Motor Control Center 1A, Reactor Plant Battery, Generator Plant Battery and Safety Systems are located in the Control Room or Electrical Equipment Room. Failure of the ventilation system should not prevent this equipment from fulfilling its safe shutdown or accident mitigation functions, though an extended ventilation system outage during plant operation could possibly result in generation of a spurious scram signal. The operation of these systems during failures of the Control Room and Electrical Equipment Room Ventilation System supports this statement.
Even if failure of the ventilation system affected equipment in the Control Room or Electrical Equipment Room, safe shutdown of the plant can be conducted from within the Containment Building. An emergency procedure exists covering reactor shutdown and cooldown when the Control Roma is inaccessible or if all vital control room instrumentation is lost. Failure of Electrical Equipment Room Ventilation would have no effect on the Reactor Building Motor Control Center 1A or the Diesel Building Battery, since they are housed in other buildings. Therefore, plant shutdown and accident mitigation could be successfully performed even if failure of the Control Room and Electrical Equipment Room Ventilation System led to failure of the equipment it services.
In conclusion', other than those actions identified under TMI Item III.D.3.4, no further modifications need to be made to the Control Room and Electrical Equipment Room Ventilation System.
E.
lA Emergency Diesel Generator Ventilation The 1A Emergency Diesel Generator Room Ventilation System consists of a temperature-controlled exhaust damper.
The damper motor is powered from the Turbine Building Motor Control Center 1A, which the 1A EDG supplies during a loss of power event.
Failure of the exhaust damper ta open would not lead to failure of the diesel generator, since the diesel rediator, not the ventilation system, cools the diesel.
W?1 Ventilation is also provided to the 1A EDG Room by the incoming combustion air, which is discharged to the room via a fan and damper that operate upon start of the diesel. Both the fan and damper are also powered from TBMCC 1A. Failure of the inlet damper to open would not cause diesel failure from a ventilation standpoint, since as mentioned above, the diesel is cooled by its radiator, though the lack of combustion air could degrade the diesel performance. There would be no effect, however, on the 1B EDG since it is housed in a separate building (Refer to Section V.8).
Since lack of ventilation would not cause failure of the 1A EDG, no modifications are needed to the 1A Emergency Diesel Room ventilation.
F.
Alternate Core Spray System Ventilation l
The Alternate Core Spray Punps are located in the Intake Structure.
There is no actual ventilation system in the intake Structure.
Nonnally, durin, 'he summer, when heat buildup could be a problem, the windows are openaed to provide natural ventilation. Since operation l
of the ACS Pumps is not dependent on a ventilation system, no ventilation system modifications are needed.
VI. CONCLUSIONS In conclusion, the intent of SEP Topic IX-5, " Ventilation Systems," is met in that the worst ventilation system performance will not prevent safe shutdown, mitigation of an accident, or result in release of unacceptable amounts of radioactivity. No ventilation systems modifications are needed, other than those separately addressed in the related topics listed in Section 111.
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