- Collects and processes high/potentially radioactive waste gases (Primarily Hydrogen & Nitrogen) generated in plant in an oxygen free system to permit decay of short-lived isotopes. - Keeps exposure of onsite and offsite personnel within acceptable limits

GR- Gaseous Radwaste Flashcards by Briana Phillips

[GR] purpose?

Collects and processes high/potentially radioactive waste gases (Primarily Hydrogen & Nitrogen) generated in plant in an oxygen free system to permit decay of short-lived isotopes.
Keeps exposure of onsite and offsite personnel within acceptable limits

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[GR] Components?

gas surge header,
waste gas surge tank,
two waste gas compressors,
three waste gas decay tanks and associated piping

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[GR] Flowpath

Waste Gas Surge Header
Waste Gas Surge Tank
Filter
Compressor - (2 parallel/redundant)
Compressor Discharge Header
Waste Gas Decay Tanks
AOV Isolation Values (2)
Gaseous Discharge Filter
Flow Element,
RU- 12
Flow Control Valve
RW Exhaust

plant vent (w/ additional radiation monitors)
RU - 1

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[GR]
RW CR [GR] instrumentation power?

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[GR]
Waste Gas Compressors power? Location?

140” RW building

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[GR]
[GA - N2] interaction with [GR]?

Nitrogen for the initial system purge

subsequent purges to allow for maintenance
Auto Purge - O2 Analyzer hi alarm in surge header

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[GR]
What causes gas surge header isolation valves to auto close?
Where does the relief valve on this header discharge to?

CIAS

RW Exhaust

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[GR]
Gas Surge header MOV isolation valve power?

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[GR]
Gas surge header solenoid operated isolation valve power?

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[GR]
Gas Surge Tank purpose?

Absorbs fluctuations in system gas volume to minimize compressor operating time

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[GR]
Design temperature of Gas Surge Tank plastic liner?

200 F

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[GR]
Gas Surge Tank location?

RW 140’

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[GR]
Gaseous Radwaste compressor purpose?

Pump LP gas from surge tank to decay tanks.

-Auto controlling surge tank pressure

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[GR]
In auto, which compressor will start if there is a high surge tank pressure and the mode selector switch is in:
A-lead, B-STNBY

“A” Compressor

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[GR]
What starts both compressors in auto ?

Hi-Hi surge tank pressure

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[GR] Decay Tanks Purpose?

-holding area for waste gas to undergo radioactive day prior to atmospheric discharge.

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[GR]
What automatically causes Decay Tank Discharge Header isolation valves (34A/34B) to close? (4)
What else closes?
Is it auto or manually reopened?

1- Low D/P of [HR] exhaust fan A & B
2 - High waste gas discharge flow
3 - High Rad level
4 - High Pressure - rad monitor supply line

Solenoid AOV flow valve FV-33 causing it to close.

Manually

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[GR]
OOS when?

Surge Header Isolation valve Valve (GRN-V002) is closed
OR
All surge header inputs are red tagged closed

[GR]
Oxygen Analyzer Hi-Hi alarm set point? What else occurs?

3.75%

Isolates [GR] system by stopping the compressors and starts auto dilution of with nitrogen

[GR]
Nitrogen Dilution is secured when?

25 psig (which should reduce oxygen concentration by 50%)

[GR]
What powers auxiliary relays in the RW Control Panel?

[GR]
The 2” gas surge header receives emissions from what sources? (6)

RDT

CNTMT Refuel failed fuel detector vent

Dry Sipping Aux Pump

Gas Stripper

VCT and relief

Oxygen Analyzer return

How does [GR] interface with [HR]?

high activity portion of GR discharges to the HR system

low activity aerated waste gas is also vented from selected equipment

What is the purpose of the GR waste gas compressors? What cools them?

pump low pressure gas from the waste gas surge tank to the waste gas decay tanks for holdup prior to release

What is the purpose of the condensate pot tapped off of the GR gas surge header? Where is it located?

to collect condensation from the RDT 77' aux. building west Mech. pen. room

When would the oxygen analyzer that monitors the GR decay tanks sound an alarm?

Oxygen content of 2% or greater

What is the purpose of the GR waste gas surge tank? What is the design temp of this tank? Where is it located?

absorb fluctuations in the gas volume entering the system to minimize waste gas compressor operating time 200*F 140' RW building

When would the GR waste gas compressors auto start and stop?

to maintain waste gas surge tank pressure

Concerning the GR waste gas compressors, at what pressure does the lead and standby compressors start and stop?

lead starts on 3psig stand by starts at 5 psig both stop at 1.5 psig

Nitrogen auto-dilute trips any running GR waste gas compressor. How is the compressor reset?

turning hand switch to stop and then back to auto

At what level does the GR waste gas compressor oil level need to be? How often does each compressor need to be run and why?

.5" above full mark weekly because the compressor will lose oil priming otherwise (compressors are swapped twice a week and they run at least daily)

What is the design pressure of the GR waste gas decay tanks? Where do these tanks relieve to?

380 psig waste gas surge tank

How many GR waste gas decay tanks are normally in service at a time? At what pressure are the tanks swapped? How long must the newly isolated tank remain isolated for prior to chemistry sampling for release?

one at a time ~340 psig 45 days

[GR] Where do waste gas decay tanks release to? Where are these tanks located?

RW Exhaust then to Plant Vent (stack) RW 140'

[GR] How is waste gas decay tank release driven? Release rate? When is the release secured, unless maintenance is required?

D/P (tank to atmo) 50 SCFM >15 psi if maintenance is required, tanks completely release and are nitrogen purged

[GR] Describe the operation of decay tanks isolation valve hand switch in the Main/RW CRs. Location?

HS-34B is in the main control room and provides permission to operate UV-34A and 34B hand switch in RW CR, HS-34A. RW 140'

What is required from the Effluents group prior to reopening the GR decay tank isolation valves to start a waste gas release? What does this authorize?

Release permit which tank to release from and a flow rate

[GR] Discharge Flow Control Valve purpose? How is it controlled? Location?

Controls the rate of waste gas released to RW exhaust header. Manual selection of Fast and Slow mode. Then Auto Controller controls flow element up stream to match the rate just below the release permit flow rate. RW 140'

[GR] What protects RU-12? RU-12 Location?

flow orifice (5 SCFM) and a low flow alarm RW 140'

[GR] Where can the (4) O2 Analyzers be aligned to? (2)

Surge Header (Normal) Surge Tank Decay Tanks

[GR] What two people are notified when [GR] is lost?

Shift Manager (SM) and System Process Supervisor immediately notified

[GR] Is considered in-service when?

- Compressor = Auto - system is lined up to any one input

[GR] Tech Spec components to system? (3)

O2 monitors - 2 must be in service O2 concentration - 2% or less RU- 12 required when running

[GR] When will the nitrogen auto-dilute activate in the gas surge header, surge tank and decay tanks?

- HI-HI O2 Analyzer alarm for 5 min (3.75%)