Term
SBGT
Describe the initiation signals for SGBT. |
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Definition
-A partial group II signal starts SBGT.
-1 high or 2 downscale (26mrem/hr, .1mrem/hr) RB exhaust plenum.
-1 high or 2 downscale (50mrem/hr, .1mrem/hr) refuel floor.
-High drywell pressure (1.84psig).
-Rx low-low water level (-47"). |
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Term
SBGT
Describe the normal flow path for SBGT. |
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Definition
-Takes suction from any of 3 spaces (Primary containment, secondary containment, or RB exhaust duct which is normally aligned to the plenum).
-Travels through normally closed inlet valve (opens on initiation).
-Travels through demister, heater, HEPA filter, charcoal filter, and HEPA filter.
-Through normally open outlet valve.
-Through fan and x-connect w/orifice.
-To dilution fans and up the stack.
-Dilution fans also take dilution air from turbine building. |
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Term
SBGT
Describe the normal train for SBGT. |
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Definition
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Term
SBGT
Describe the SBGT flow alarms and interlocks. |
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Definition
-SGBT low flow start: <2800scfm will start the B train if > 10 seconds from initiation.
-SBGT low flow alarm: <3000scfm for 30 seconds. |
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Term
SBGT
Describe the heater trips and alarms. |
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Definition
-Heater cycles on flow: Trips off <1000scfm, starts at 2000scfm.
-Heater trips on high temp: >200F (alarm and light).
-Heater high temp alarm: 180F.
-Heater low delta T: <6F. |
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Term
SBGT
Describe the stack flow alarms and interlocks. |
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Definition
-Stack low flow: <3480scfm starts the standby stack fan (alarm on C-20).
-No stack flow after 20 seconds from start (alarm on C-20). |
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Term
SBGT
Describe the dilution fans and SBGT fans power supply. |
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Definition
-SBGT fans: V-EF-17A is MCC-133A, V-EF-17B is MCC-143A.
-Dilution fans: V-EF-18A is MCC-133A, V-EF-18B is MCC-143A. |
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Term
SBGT
Describe recently irradiated fuel. |
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Definition
| Fuel that has occupied part of a critical reactor core within the previous 24 hours. |
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Term
SBGT
Describe the demister. |
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Definition
| Removes moisture which drains to radwaste via loop sea. |
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Term
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Definition
-20kW heater.
-Designed to reduce air to 70% humidity at max inlet temp of 150F. |
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Term
SBGT
Describe the HEPA pre and post filters. |
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Definition
-99.97% efficient for particulates < 0.3 microns.
-Max temp of 250F. |
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Term
SBGT
Describe the charcoal filter. |
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Definition
| -Efficiency of 99.9% of total iodines at 70% relative humidity and temp of 150F. |
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Term
SBGT
Describe the response of fans and dampers on a partial group II signal. |
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Definition
-All fans that are exhaust or suction trip.
-All recirc fans continue operating.
-Dampers trip shut. |
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Term
SBGT
Describe loss of power Group II initiations. |
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Definition
-Loss of power to Radiation Monitors will result in an upscale trip (Y50 and Y40).
-Loss of power to logic will initiate a partial Group II (Y70 and Y80). |
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Term
SBGT
Describe system flow rates. |
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Definition
-SBGT fans rated at 4400cfm.
-Normal system flow set at approx. 4000cfm.
-Dilution supply approx. 5000cfm. |
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Term
SBGT
Describe secondary containment rated pressures. |
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Definition
-The building is designed to withstand an internal pressure of 7″ of water without structural failure.
-The Reactor Building is designed so that its in-leakage rate is not greater than 4000 cfm (approximately 3 building air changes per day) under neutral wind conditions when the building is subjected to an internal negative pressure 0.25″ of water.
-Exfiltration from the building should not exceed 100% of the building volume per day with negative internal pressure of 0.25″ water and wind speeds of 40 miles per hour. |
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Term
SBGT
Describe the major controls for SBGT. |
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Definition
-Master control switch: 1 for each train, 2 positions (auto, manual).
-Test push button: Simulates an auto start (does not give partial group II), isolates associated dampers.
-Fan trip bypass: bypasses trip for plenum and turbine building fans.
-Reset push button: Used to return to normal after initiation. |
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