Term
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Definition
•Maintain the Fuel Handling Building (FHB) area temperature between 60°F and 105°F based on outside air temperature being between 0°F and 93°F with a relative humidity on the average of < 70%.
•Maintain the FHB at a slight negative pressure ~0.125 in. with respect to atmosphere to prevent an uncontrolled release of radioactive materials from the Fuel Handling Building.
•Direct air flow from clean or less contaminated areas to areas of higher contamination (ALARA considerations).
•Route air from the Spent Fuel Pool and high contamination areas to the filter unit before releasing it to the atmosphere to meet the requirements of 10 CFR 20*.
•* Standards for Protection Against Radiation
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Term
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Definition
•The Fuel Handling Building Ventilation System (FHV) is designed to exhaust the Spent Fuel Pool Area at 60 air changes per hour within 10 feet above the pool during design conditions for spent fuel storage.
•Of the FHV System total operating capacity (20,000 cfm), 75% (15,000 cfm) is exhausted from the pool surface, and the remaining 25% (5,000 cfm) of system capacity from other parts of the building.
•The FHV is designed to maintain the FHB between 60° and 105°F at less than 70% relative humidity.
•Maintain the FHB at a slight negative pressure with respect to atmosphere during normal and emergency plant operations.
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Term
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Definition
•Radioactive exhaust (gaseous effluent) from the FHB is controlled to satisfy the requirements of General Design Criterion 60, “Control of Radioactive Releases to the Environment” of App. A to 10 CFR 50, and monitored to satisfy General Design Criterion 64, “Monitoring Radioactivity Releases” of App. A to 10 CFR 50.
•Safety related ductwork, components and supports are designed to remain functional during and following a seismic event.
•Only the FHB Exhaust System is designed and classified as safety related.
§No single device shall jeopardize the capability of the system to perform its safety related function.
§Controlled release of radioactivity will not prevent safe shutdown of the plant.
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Term
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Definition
•Fuel Handling Area Ventilation System is a once through filtered-air system that continuously ventilates the normal operating areas:
§New Fuel Container Lay Down Area
§Fuel Handling Area
§Spent Fuel Storage Pool
§Transfer Pool
§Decontamination Pit
§Electric Equipment Room (Skimmer Pump Room)
§New Fuel Storage Pit Area
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Term
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Definition
•Supply Fan (VHE24)
•A 100% capacity (20,000 cfm) air Supply Filter Unit (VHE500)
•Hot Water Heating Coil (HWE69/HWE41)
•Pneumatically operated Inlet Damper (FHV8)
•Instrumentation, controls and ductwork
•3 Hot Water Unit Heaters are provided for the Fuel Handling Building, and 2 for the Annex.
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Term
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Definition
•Two (2) 50% capacity fans (VHE20/21)
•One (1) 100% capacity HEPA Filter Unit (VHE502/302) with inlet and outlet isolation dampers (FHV1/2) for normal operation
•One (1) 100% capacity HEPA and Charcoal Filter Unit (VHE503/303) with inlet and outlet isolation dampers (FHV3/4) for high radiation level operation
•Instrumentation, controls and ductwork
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Term
| When do the Exhaust Fans Auto Swap and why? |
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Definition
Both Exhaust Fans and 21 Exhaust Filter I/S is the normal lineup. On a FHB HI Rad signal (R5/R9 Signal) Exhaust Filters swap, 22 going into service, 21 out of service.
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Term
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Definition
•Two 50% fans both normally I/S - 12,000 cfm each
•Take suction from I/S Exhaust Filter and discharge to Plant Vent
•Start/Stop PB at CC1
•AUTO start : R5/R9 high rad signal
•AUTO Trip: SEC Mode II, III, IV (remain I/S during Mode I)
•Power supplies
- 21/11—1/2A 460V Vital Bus
- 22/12—1/2B 460V Vital Bus
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Term
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Definition
•FHV5 and FHV6 are air operated variable inlet vanes
•Vanes modulate to maintain building at slightly negative pressure
•Vanes fail open on loss of power or control air
•Atmospheric pressure and building pressure compared to generate a Control Air signal to the vanes positioner when “Inlet Vane Pressure Control” mode selected at CC1:
§D/P more negative than 0.125" wg ® vanes modulate closed to lower air flow and lower D/P
§D/P less negative than 0.125" wg ® vanes modulate open to raise air flow and raise D/P
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Term
What happens to the FHBVS ...
if you over fill the SFP? |
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Definition
| Flooding of the FHB Vent Duct system. |
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