General

Question 1

When are the Intermediate Range Monitors utilized?

Answer 1

The IRMs are used during startup/heatup or other low power operations.

Question 2

What are the differences between the Source Range Monitors and the Intermediate Range Monitors?

Answer 2

The IRMs have the same enrichment in their Uranium Oxide coating but it’s a thinner layer. The IRMs also operate with a lower voltage and a lower Argon gas pressure.

Question 3

How does an Intermediate Range Monitor differentiate between neutron and gamma pulses?

Answer 3

The “Mean Square Voltage” technique, or “Campbell Method”, squares each pulse until the gamma pulse becomes insignificant.

Question 4

What provides power the Intermediate Range Monitors?

Answer 4

The Reactor Protection System provides the IRMs power.

RPS A - IRM A, IRM C, IRM E, IRM G
RPS B - IRM B, IRM D, IRM F, IRM H

Question 5

What levels, in the Core, are the Full In and Full Out position for the IRMs?

Answer 5

Full In - 18 inches above Core midplane

Full Out - 30 inches below the Core

Question 6

How fast can the Intermediate Range Monitors be inserted/retracted, and how long does it take to fully removed the Intermediate Range Monitors from the Core if fully inserted?

Answer 6

The Intermediate Range Monitors move at a speed of 3 feet per minute, therefore it will take 3.5 minutes to fully retract the IRMs from the Core if they are fully inserted.

Question 7

How many ranges do the Intermediate Range Monitors have?

Answer 7

The IRMs have TEN ranges.

Question 8

What factor do the Intermediate Range Monitor readings change by when moving from one range to the next?

Answer 8

One range up/down will change the current readings by a factor of approximately 3.1(square root of 10). SO, if you range up/down twice, in the same direction, the readings will change by a factor of ten.

Question 9

What are the approximate power levels at the top of ranges 6, 8, and 10?

Answer 9

Range 6 - .4 %
Range 8 - 4 %
Range 10 - 40 %

Question 10

How does placing the Mode Switch in RUN affect the Intermediate Range Monitors?

Answer 10

All of the Intermediate Range Monitor Scrams and Rod Blocks are bypassed.

Question 11

How does placing the IRM Bypass Joystick in Bypass affect the Intermediate Range Monitors?

Answer 11

All of the Intermediate Range Monitors Scrams and Rod Blocks are bypassed.

Question 12

What Intermediate Range Monitor signals will produce a Rod Block?

Answer 12

1) INOP
2) Downscale 5/125
3) Upscale 80/125
4) Detector not Full In

Question 13

What Intermediate Range Monitor conditions produce an “INOP” signal?

Answer 13

1) Function Switch NOT in Operate
2) Card out of file
3) High/Low voltage
4) Detector unplugged

Question 14

How can an Intermediate Range Monitor Downscale Rod Block signal be bypassed?

Answer 14

The associated IRM Detector on range 1 will bypass the Downscale Rod Block signal. (IRM bypassed or Mode Switch in RUN bypasses all Rod Blocks)

Question 15

How can an Intermediate Range Monitor Upscale Rod Block signal be bypassed?

Answer 15

The IRM Upscale Rod Block signal can be bypassed if the IRM is bypassed or the Mode Switch is in RUN.

Question 16

How can an Intermediate Range Monitor “Detector Not Full-In” Rod Block signal be bypassed?

Answer 16

The IRM “Detector Not Full-In” can be bypassed if the IRM is bypassed using the joystick or the Mode Switch in RUN.

Question 17

What Intermediate Range Monitor signals will produce a Scram?

Answer 17

1) INOP

2) High High Upscale 120/125

Question 18

How can the Intermediate Range Monitor Scram signals be bypassed?

Answer 18

The IRM Scram signals can be bypassed if the IRM is bypassed or the Mode Switch is in RUN.

Question 19

When do the Downrange and Up Range lights illuminate for the Intermediate Range Monitors?

Answer 19

15/125 - Downrange Light

75/125 - Up Range Light

Question 20

What Intermediate Range Monitor range is where the Point of Adding Heat is usually reached?

Answer 20

Range 7