C5102 - IRMs

Question 1

What’s the purpose of IRMs?

Answer 1

Intermediate Rod monitoring - monitors Rx power for startup, shutdown, and refueling (mainly heatup cool down)

Question 2

When do IRMs come out?

Answer 2

IRMs come out during RUN mode

Question 3

Do IRMs have intermediate positions?

Answer 3

NO

They are either full in or full out

Question 4

How many IRMs do we have?

Answer 4

8

Question 5

What are the IRMs made of?

Answer 5

Fission chamber charged with 18 psig Argon gas

(100 vdc)

Question 6

What are the IRM power supplies?

Answer 6

14B11 480v for drive mechanism

Question 7

What is IRM normal position?

Answer 7

either full in or full out. No mid position

Question 8

What are the INOP signals?

Answer 8

SOO/MU/HVL

Switch out of operate
Module unplugged
High voltage low (<100 vdc)

Question 9

What happens if an IRM is INOP?

Answer 9

Scram and Rod block (1/2 scram if only 1 division is affected)

Question 10

When should IRM be ranged up?

Answer 10

75% of scale

Question 11

When should IRM be ranged down?

Answer 11

25% of scale

Question 12

How do you bypass an IRM?

Answer 12

Joystick

automatically bypassed in RUN

Question 13

How many IRMs can be bypassed?

Answer 13

1 IRM per trip system (one for A and one for B)

Question 14

What will cause a SCRAM with logic?

How many signals per division?

Answer 14

1 SCRAM signal on each division

SCRAM on 1 division is only a half-scram

Question 15

What are the Rod blocks for IRMs?

Answer 15

DUDI

D - downscale <5/125 (bypassed in RUN or IRM range 1)
U - upscale >108/125 (bypassed in RUN)
D - detector not full in (bypassed in RUN)
I - INOP (bypassed in RUN)

Question 16

Can you have a rod block and SCRAM at the same time?

Answer 16

YES

Question 17

What are the SCRAM setpoints for IRMs

Answer 17

> 120/125 (bypassed in RUN)

INOP (bypassed in RUN)

Question 18

What are the ranges?

Answer 18

1                            0-40
2                           0-125
3                           0-40
4                           0-125
5                            0-40
6                           0-125
7                             0-40
8                            0-125
9                            0-40
10                           0-125

** 1 to 2 - nuber tays the same, change decades by a factor of 10**

Ex. Range 3 – 37/40.
Range 4 – 3.7/40

Question 19

How many decades?

Answer 19

5

Question 20

What power level does IRM operate?

Answer 20

.0001% to 35% power

Question 21

How many ranges are there?

Answer 21

10 ranges

Question 22

what’s the voltage pre-amplifiers?

Answer 22

Increase the signal to noise ratio to amplify signal to usable level

Question 23

what are the retract permissives for IRMs?

Answer 23

Mode switch in RUN

IRM bypassed can be withdrawn any time but can cause a rod block