What CPC limit protects fuel centerline temperature from exceeding SAFDL?
LPD limit (<21 kW/ft) protects SAFDL fuel centerline temperature.
What is the purpose of CPC trips?
CPC trips protect the core to prevent exceeding SAFDL.
What CPC conditions can cause a DNBR pre-trip and CWP?
Low pressurizer pressure and high T-hot.
Why do low PZR pressure and high T-hot affect DNBR?
Both lower DNBR through the CPC flow calculation.
What canned value does CPC use for ASI below ~45% power?
45% power value (45/51 rule) to avoid an auxiliary trip.
Why does CPC use the 45% power canned value for ASI?
To prevent unnecessary auxiliary trips during low power conditions.
What happens to DNBR if RCP speed decreases?
DNBR decreases.
At what RCP speed does CPC trip on DNBR degradation?
95% rated RCP speed.
What is the effect of 12 finger slips in the core with no CPC trip?
Xenon builds over ~6 hours and increases CPC penalty.
When are CPC DNBR and LPD trips automatically inserted?
When power increases above 10^-4.
What CPC signal failure can cause a channel trip?
RCP speed signal failed low.
What parameters are used in the CPC mass flow calculation?
T-hot, RCP speed, and pressurizer pressure.
What happens to DNBR if RCS pressure decreases?
DNBR decreases.
What two conditions commonly lower DNBR?
Lower RCS pressure or rising power.
How is LPD margin determined on CPC instrumentation?
LPD margin meter reading corresponds to the 21 kW/ft limit.
How can actual DNBR be calculated from the CPC DNBR margin meter?
DNBR margin meter value + 1.34 = DNBR.
What signals does CPC use to calculate DNBR and LPD?
Excore detector signals.
What does the CPC red pen represent?
Compensated neutron flux.
What does the CPC green pen represent?
Uncompensated neutron flux.
What determines the magnitude of the CPC penalty factor?
The direction of CEA deviation.
What measurements are used in CPC temperature and rod shadow calculations?
Temperature shadow uses coldest Tcold; rod shadow uses RSPTs.
What conditions initiate a CPC CWP?
High PZR pressure pre-trip, low DNBR pre-trip, high LPD pre-trip, RPCB, or CEAC/CEA pre-penalty.
What temperature is associated with the zirconium-water reaction concern?
2200°F.
What does CPC do if one CEAC becomes inoperable?
Uses the last valid input, compares to the other CEAC, and takes the most conservative value.
