Nuclear Instrumention system Flashcards
N-31/32 are what kind of detector?
Proportional Counter, filled with BF3 gas. Has a pulse dampner in it to ignore Nuetrons pulses on the the detector and only sense the gamma.
N-31/32 has what trip? What is before this?
Source Range HIgh Flux
(High flux source range alarm which also causes CV evacuation alarm)
What effect does loosing Instrument power have on Source and Intermediate Range NI’s?
A lost of instrument power with cause a reactor trip unless the bypass switch is closed. (Always before P-6/10 is blocked)
What effect does loosing control power have on Source and Intermediate Range NI’s?
Causes Reactor Trip unless above P-6/10
If High Flux at shutdown switch is blocked, will the Shutdown alarm and CV horn sound?
NO, if in block neither the alarm or horn will sound
N-35/36 is what kind of detector?
Can in a Can. Both the inner and outer surgaces of the outside chamber is coated with Boron-10.
Over compensated reads low
Under compensated reads high
Over Power Rod Stop bistable is what conicident?
1/4 at 103%
Any Power Range NI will stop rods
P-6 has a premissive Defeat (2/2 pushbuttons) when can it be used?
Only operable below P-10
If NI-51A/B are indicating <10^3cps and NI-35/36 are not reading below 10^-10amps
N-35/36 rod stop set point and conicident?
20% CE 1/2
Remember OPdelatT…..?
Does not have pressure fed into it.
N-44 does not feed into what?
OT Delta T
OP Delta T
APP
IR HI Level ROd Stop
Setpoint and conicident
20% CE
1/2 IR Detectors
APP
PR Dropped rod setpoint?
5% power change in 5 seconds
APP
PR overpower rod stop
setpoint conicident?
103% on 1/4 PR detectors
NI-51/52 we need because of what OE?
Three mile island
Axial Flux Difference tech spec is applicabile when? What is the required action, and completion time?
Mode 1 with THERMAL power >= 50%
Reduce THERMAL power <50%
Within 30 minutes
Remember greater than or equal too
Two source range neutron flux channels inoperable below P-6
Open Reactor Trip breakers immediatley
If one channel is inoperable (SR/IR/PR)
Verify interlock is in required state for existing unit conditions (1 hour)
If in mode 6, two SR instruments shall be operable.
If one is inoperable, Verify one PAM source range neutron flux monitior provides indication in the CR (15mins)
AND
Log PAM source range count rate (30mins, and then once 30mins thereafter)
PR detectors provide signals to:
OP Delta T/ OT Delta T
Current comparator Drawer (QPTR alarms)
ERFIS (AFD alarms)
If two PR detectors are inoperable, what does this do to SR?
Creates a false P-10 signal that prevents the operation of the SR instruments
When a SR or IR detector looses Istrument power what are your indications on the Drawer?
Indication falls to zero, lights light up
When a SR or IR etector looses Control Power what are you indications on the drawer?
Indication stays on needle, lights go out
