C5102 - IRMs Flashcards
What’s the purpose of IRMs?
Intermediate Rod monitoring - monitors Rx power for startup, shutdown, and refueling (mainly heatup cool down)
When do IRMs come out?
IRMs come out during RUN mode
Do IRMs have intermediate positions?
NO
They are either full in or full out
How many IRMs do we have?
8
What are the IRMs made of?
Fission chamber charged with 18 psig Argon gas
(100 vdc)
What are the IRM power supplies?
14B11 480v for drive mechanism
What is IRM normal position?
either full in or full out. No mid position
What are the INOP signals?
SOO/MU/HVL
Switch out of operate
Module unplugged
High voltage low (<100 vdc)
What happens if an IRM is INOP?
Scram and Rod block (1/2 scram if only 1 division is affected)
When should IRM be ranged up?
75% of scale
When should IRM be ranged down?
25% of scale
How do you bypass an IRM?
Joystick
automatically bypassed in RUN
How many IRMs can be bypassed?
1 IRM per trip system (one for A and one for B)
What will cause a SCRAM with logic?
How many signals per division?
1 SCRAM signal on each division
SCRAM on 1 division is only a half-scram
What are the Rod blocks for IRMs?
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)
Can you have a rod block and SCRAM at the same time?
YES
What are the SCRAM setpoints for IRMs
> 120/125 (bypassed in RUN)
INOP (bypassed in RUN)
What are the ranges?
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
How many decades?
5
What power level does IRM operate?
.0001% to 35% power
How many ranges are there?
10 ranges
what’s the voltage pre-amplifiers?
Increase the signal to noise ratio to amplify signal to usable level
what are the retract permissives for IRMs?
Mode switch in RUN
IRM bypassed can be withdrawn any time but can cause a rod block
