HR- Radwaste HVAC Flashcards by Timothy DeRossett

What are the functions of the Radwaste Building HVAC system?

maintain ventilation in the process equipment areas

provide personnel safety in access areas

restrict the spreading of airborne radioactivity

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What portion of the Radwaste Building HVAC system features the recirculation of air? How is fresh air and pressurization introduced to the RW control room?

Radwaste Building Control room

recirc air is mixed with air from the RW supply AHU air

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What temperature is maintained in the Radwaste Building Control room?

70 – 80F

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Why does the HR system maintain the Radwaste building at a slightly negative pressure?

Ensures that the amount of uncontrolled/unmonitored release of potentially radioactivity air to the atmosphere from the Radwaste Building is minimized

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What systems will the HR system collect vent discharges from?

Gaseous Radwaste (GR)
Liquid Radwaste (LR)
Solid Radwaste (SR)
Chemical and Volume Control (CH)
Nuclear Sampling (SS)
Radioactive Waste (RD)

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How does DS system interact with HR?

Provides water to the air washers

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What system provides cooling water to the Radwaste Control Room ACU?

Normal Chilled Water System (WC)

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What components of the Gaseous Radwaste System vent to the HR system?

System release path discharges upstream of the AFUs

Waste gas surge tank relief valve

GR compressor pre-filter, suction filter and package

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What components of the Liquid Radwaste system vent to the HR system?

LR system evaporator, surface condenser and heater

Concentrate monitor tanks

LR system holdup tanks

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What components of the CH system vents to the HR system?

BAC condensate ion exchanger and BAC condenser

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What component of the Nuclear Sampling System vents to the HR system?

Oxygen analyzer exhaust fan

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What part of the Radioactive Waste Drain System (RD) vents to HR system?

RD system RW building sump

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What system provides air to the HR system air dampers? What happens if air is lost?

Instrument air

If air is lost, the dampers fail closed which will cause the AHUs and AFUs to trip on overload

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Which radiation monitor tracks the GR system release flowpath?

RU-12

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Which radiation monitors keeps track of the plant vent?

RU-143 and 144

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The discharge of the Radwaste Building HVAC system is monitored by what component? Where is this component located?

RU-14, upstream of the AFUs

RW building roof

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What HR exhaust does RU-15 monitor? Where is this monitor located?

Combined exhaust from the Waste Gas System area

140’

Where do the Radwaste Building HVAC normal AHUs drain/overflow to?

OW, Control Building West sump

Concerning the Radwaste Control Room Normal AHU, when would the Duct Heater energize?

Supply air temperature is low (<50F), if the heater airflow is not low and if the heater supply breaker is closed

Where are the Normal supply AHUs located?

Radwaste Building roof

Concerning the Normal Supply AHUs, how are the fans and dampers interlocked?

Each damper is interlocked with its respective AHU fan such that when the fan is running the damper is open and when the fan is stopped the damper is closed

Concerning the Normal Supply AHU Duct heater, when would it energize?

Energized if Radwaste Building exhaust air temperature is low (<75F) if the airflow over the heater is not low and if the associated AHU fan is running

Where are the controls for the HR system located at?

Radwaste Control Panel in the Radwaste Control room on the 120’ level of the Radwaste Building

How many signals are required to start the air washer pumps and where do those signals come from?

Two signals
A permissive signal from the associated running AHU fan and a signal from the intake air temperature controller when the outside air is 80F or above

What is the purpose of the Exhaust Normal Air Filtration Units? What components are in them? Where do they exhaust to?

Two 50% capacity Exhaust units operating in parallel are provided to filter dust and particulate matter from the air exhausted from the Radwaste Building contains high efficiency filters and HEPA filters plant vent

Where is the Laundry and Decon Facility located?

Unit 1 only

Concerning the Decon and laundry facility Normal AFU and AHU, which one is placed in service first and why?

AFU To avoid positively pressurizing the Decon facility

What components in the HR system are powered by NH?

RW building Normal AHU fans RW building Normal AHU recirculation pumps (air washer pumps) RW control room Normal AHU fan and fan motor space heaters RW control room AHU heater

What components in the HR system are powered by NG?

AFU fans and the normal supply duct heaters

Shutting down one AFU dictates the shutting down of one AHU and vice versa. For the shutdown, which one is secured first and why?

AHU shall be shutdown before the AFU to assure negative pressure is maintained in the Radwaste Building

If both AFUs and both AHUs are to be stopped, whose permission do you need?

Shift Manager/CRS

How is the HR system affected by a loss of Instrument Air?

At 30 psig and decreasing, the Radwaste Building Normal Air Handling Units damper fail closed and the fans will trip on thermal overload Radwaste Building Normal Exhaust AFU isolation dampers fail closed at 30 psig and decreasing and the exhaust fans will trip on thermal overload. This will cause the flow control valves for GR system to go closed, stopping a GR release if one is in progress Radwaste Building Control Room AHU will lose its chilled water supply due to two valves going closed. The fans will keep running, recirculating ambient Control Room Air only

What happens on a loss of NK? What if NKN-D42 is lost?

All Radwaste Building AHUs and AFUs dampers fail closed All running AHUs and AFU fans trip on overload (D42) Radwaste control room annunciator is lost

How does HR interface with NG?

powers RW normal duct heaters and normal AFU fans

How many HR supply AHUs are there? What is the capacity of each unit and how are they aligned? What components are in it?

two 50% in parallel louvers, dry media filter, evap cooling pad, pump, fan and heater down stream

Why is it okay to recirculate the air in the RW control room?

no source of potential airborne radioactivity

Where is the RW control room normal AHU located?

130' RW building

What does RU-39 monitor?

Decon and Laundry facility Normal AFU exhaust

What happens when a RW normal AFU is shutdown?

the relative train supply AHU is also shutdown to provide negative pressure

If one train of a HR AHU/AFU is lost, What would that impact? If both trains were lost?

potentially exceed the humidity set point and require the BAC release flowrate to decrease waste gas release would auto secure based on D/P across AFU