Excore Flashcards
State the range and designation of the Source Range detectors
10^0 to 10^6 CPS
10^-9% to 10^-3%
N-31/32
State the range and designation of the Intermediate Range detectors
10^-11 to 10^-3 Ion chamber amps
3x10^-6 to 300%
N-35/36
State the range and designation of the Power Range detectors
0 to 120%
N- 41/42/43/44
State how the Source Range detector senses only Neutron flux
A Pulse Height Discriminator is used to filter out smaller gamma pulses
State how the Intermediate range detectors senses only Neutron Flux
A Compensated Ion Chamber
The inner chamber senses only gammas and is used subtracted from the outer chamber
State the issue with compensating voltage on an Intermediate range detector
Too much Compensating volts the detector will read low
Too little Compensating volts and the detector will read high
State how the Power Range detectors senses only Neutron Flux
It doesn’t. Gammas are proportional to reactor power.
Discuss Channel Comparator for PR NI
If the highest channel (41/42/43/44) minus the lowest channel is 2% or more apart then a VAS alarm will be recieved
Discuss Flux deviation comparator for PR NI
If the highest upper portion of PR NI is 2% or more away from the average then an VAS alarm will be received.
Same for lower portion of the PR NI
Discuss how Neutron shifts over core life
Neutron flux increases and shifts outward. This causes the detector to increase indication.
State T.S. 3.2.1 (AFD) LCO and Action
The Indicated AXIAL FLUX DIFFERENCE shall be maintained within the limits of the COLR
MODE: 1 and above 50% power
a. With the indicated AFD* outside of the applicable limits specified in the COLR:
1. Either restore the indicated AFD to within the COLR specified limits within 15 minutes, or
2. Reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within 30 minutes, and
3. THERMAL POWER shall not be increased above 50% of RATED THERMAL POWER unless the indicated AFD is within the limits specified in the COLR.
