Process Radiation Monitors (D11) Flashcards

1
Q

Main Steam Line Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

MSL Rad Monitors - K603

Ion Chamber x4

A&C - RPS ‘A’
B&D - RPS ‘B’

INOP*
DNSC <10mr/hr
Hi 2.5 X normal
Hi-Hi* 3 X normal (upscale normally)
* - These alarms cause actuation

Downstream outbrd MSIV’s in Steam Chase

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2
Q

MSL Rad Monitor Trips

A

AUTO ACTIONS only occur <20% RTP

Trip system is set up with a 1 out of 2 taken twice logic (Failure of any 1 monitor does not result in inadvertent action)

Trip in RPS Channel A or C AND RPS Channel B or D (Hi-Hi or INOP) causes auto actions to limit rad releases from plant:

  • MVP & SPE trip and isolate
  • B31F019 & F020 isolate (A&B- F019 and C&D- F020)
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3
Q

Air Ejector Off-Gas Pretreatment Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Air Ejector Off-Gas Pretreatment Rad Monitors

Ion Chamber x2

RPS B (Norm)
Inst. A (Backup)

INOP
Hi
Hi-Hi

Norm- Alarm only
B/U- indications only NO ALARM

Before Holdup Volume

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4
Q

Air Ejector Off-Gas Post-treatment Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Air Ejector Off-Gas Post-treatment Rad Monitors

Scintillation x2

24 VDC A/B

INOP*
DNSC*
Hi* 
Hi-Hi  
Hi-Hi-Hi*
(Isol - combo of 1 in both detectors)
* - These alarms cause actuation

After carbon beds, before stack

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5
Q

Main Stack Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Main Stack Rad Monitors

Scintillation x2

24 VDC A/B

DNSC
Hi
Hi-Hi** (KAMAN START)

Main Stack

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6
Q

Liquid Process Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Liquid Process Rad Monitors

Scintillation x2

24 VDC B

INOP*
DNSC* 3cps
Hi*(NOTE 1)
* - These alarms cause actuation

PSW and RBCCW are alarm only

NOTE 1: Actuation only occurs on Liquid Rad waste (low dilution flow actuation 10,000gpm). PSW and RBCCW detectors only have hi alarm, no actuation.

PSW: detector in combined discharge to river
RBCCW: detector in combined return from components prior to HXs
Radwaste: detector in discharge line prior to river (physically in bottom elevation of radwaste)

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7
Q

Rx Bldg Plenum (Stack) Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Rx Bldg Plenum (Stack) Rad Monitors

Scintillation x2

U2: 2R25-S101 off of 600 C
U1: INST A & B

DNSC
Hi
Hi-Hi** (KAMAN START)

Reactor Bldg Stack

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8
Q

Carbon Bed Vault Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Carbon Bed Vault Monitors

G-M x2

RPS B

DNSC 1mr/hr
Hi 50R/hr

Waste Gas Treatment Bldg

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9
Q

Rx Bldg Exhaust Ventilation Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Rx Bldg Exhaust Ventilation Rad Monitors - K609

G-M x4

A&C - RPS ‘A’
B&D - RPS ‘B’

DNSC
Hi
Hi-Hi* 18mr/hr
* - These alarms cause actuation

Reactor Bldg Ventilation

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10
Q

R/F Floor Exhaust Ventilation Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

R/F Floor Exhaust Ventilation Rad Monitors - K611 + U2: K634/K635

G-M U1: x4, U2: x12

A&C - RPS ‘A’
B&D - RPS ‘B’

DNSC 
Hi 
Hi-Hi* 18mr/hr (K611) 
U2 only: 6.9mr/hr (K634), 5.7mr/hr (K635)
* - These alarms cause actuation

Refuel Floor Ventilation

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11
Q

Area Rad Monitors (ARMs)

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Area Rad Monitors (ARMs)
U1: K601B or D
U2: K601A or M

G-M: Multiple

INST. A

DNSC
Hi* 15 mR/hr
* - These alarms cause actuation

Multiple areas
RF ARM Hi (15 mR/hr) → MCREC in pressurization mode

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12
Q

Kaman Rad Monitors

  • Type
  • # of detectors
  • Power Supply
  • Alarms
  • Location
A

Kaman Rad Monitors (accident range)

Beta-Gamma: x1 Med, x1 High

INST A

START signals on Hi-Hi from other rad monitors, must be MANUALLY shutdown

Main Stack
Rx Bldg: Turbine Bldg 164’

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13
Q

Offgas Post Treatment Trip Response

A

For trip to occur & Offgas system to isolate (F057 stack isolation valve) - both detectors must have any combination of Hi-Hi-Hi, Downscale, or INOP alarms

To close the bypass valve around the carbon beds (F043), only one detector has to have a Hi alarm.

Hi alarm occurs
Carbon bed bypass valve closes (F043) & Carbon bed inlet valve opens (F042)

Hi-Hi-Hi, INOP, or Downscale occurs

  • Offgas Stack Isolation Valve closes (2N62F057/1N62F527)
  • Loop Seal Valves close (N62F030A/B, 2N62F085, 1N62F086, 1N62F111A/B)
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14
Q

Process Rad Monitor high setpoint basis, downscale setpoint and dilution flow requirements

A

Liquid Radwaste - isolates on Hi, Inop, Downscale preventing discharge to river closing G11F184 & G11F185

High rad level trip is set using data to determine a reasonable level that is high enough to prevent spurious trips and low enough to prevent any excess radioactive release to the environment

Downscale/INOP trip is set at 3 cps

Low Dilution Flow @ 10,000 gpm also isolates (not associated w/ rad monitor)

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15
Q

Rx Building Vent Rad Monitor Isolation Signal Response

A

Isolation signal Hi-Hi (18 mR/hr) in any area, either Unit causes Isolation of both Units RB & RF Vent Systems & starts ALL 4 SBGT Fans

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16
Q

Loss of RPS effect on PCIS, SCIS and SBGT

A

U2 – Loss of A only – Half PCIS Gp 2 isolation; NO SC isolation, NO SBGT start (SCIS logic powered from INST A)

U1 – Loss of A – Half PCIS Gp 2 isolation (inboard); SCIS isolation & Both unit SBGT start (SCIS logic powered from RPS)

U1 – Loss of B – Half PCIS Gp 2 isolation (outboard); SCIS isolation & Both unit SBGT start (SCIS logic powered from RPS)

17
Q

When are MSL rad monitor setpoints adjusted?

What affects MSL rad levels?

A

Prior to placing H2 Injection in service, setpoint of MSL Rad Monitors must be raised to prevent an inadvertent trip signal
≤ 20% RTP (≤ 2.5 X NORM full power background)
> 20% RTP raised up to 9.99 x E5 = No trips b/c set point too high but alarms still function at normal level

AUTO ACTIONS only occur <20% RTP

Alarms on 601 and 603. 603 is trip, 601 is alarm used when >20% to alert manual action required to trip.

When concentration of H2 is increased, free N2 will combine w/ free H2 to form ammonia

Radioactive N2 (N-16) carried into steam lines as ammonia & can cause large changes in MSL Rad Monitor readings

18
Q

Unit 2 is operating at rated power when offgas flow rises from 10 scfm to 55 scfm due to condenser in leakage.

What process rad monitors will be affected by this change in plant conditions and why?

What alarms would be received and what automatic actions would occur?

A

Off gas pre-treat rad monitor levels will lower significantly due to dilution of the offgas. Post treat rad levels will eventually lower also.

Pre-treat Rad monitor downscale annunciator may be received as a result of this change. Pre-treat rad monitor downscale alarm will be received when lowering power or changes in off-gas flow.

19
Q

At which panels are rad monitors read in the MCR?

A

2H11-P600: Area/Process Radiation (Main Steam, RBCCW/PSW, Rx Bldg/Refuel Floor Vent, Off Gas Pre/Post-Treat) - Yokogawas

2H11-P604: Process Rad Monitors (Radwaste/PSW effluent) - NUMACs

2D21-P600: Panel by 654/657: Area Rad Monitors - Small analog units with the small reset pushbuttons for individual areas

20
Q

What starts/stops KAMANs?

A

Auto starts are only from Rx Bldg Plenum (Stack) or Main Stack rad monitor Hi-Hi

KAMANs can only be stopped manually.