NON-NUCLEAR INSTRUMENTATION Flashcards
(30 cards)
What is the maximum reactor power allowed when transferring FW temp or FW flow instruments?
Ensure Rx Power <99.5% to avoid plant stability issues.
What is the minimum number of OPERABLE channels required for most NNIs?
Most NNIs require a minimum of 2/1 OPERABLE channels.
What is the time frame to restore OPERABLE NNI channels if the minimum is not met?
Restore OPERABLE within 7 days (48 hours for Pzr level) or be in HSD in 6 hours.
What parameter is SASS’d but does NOT go to ICS?
Narrow range pressure.
What mismatch criteria BLOCKS auto signal transfer?
3% Δ full scale mismatch (FW flow >4% Δ and FW valve ΔP >10 psid).
What does a red light indicate in NNI systems?
A mismatch has occurred (will be on both buttons).
What does a white light indicate in NNI systems?
Instrument has swapped to the second instrument on actuation.
What is the function of buffer amplifiers in NNI systems?
Prevent RPS from being affected by downstream failure.
How does an RTD failure manifest?
OPEN = failed high, SHORTED = failed low.
How does lowering supply voltage affect RTD temperature readings?
Lowering supply voltage results in lower temperature readings.
How does ICS and RPS handle temperature compensation?
ICS = Temp compensated, RPS = Temp calibrated.
How is subcooling margin conservatively set for rapid cooldown and heat-up?
Conservatively low for rapid cooldown (steam line rupture) and conservatively high for rapid heat-up.
What happens to MU-V-17 if Pzr temp fails LOW?
Indicated level goes DOWN → MU-V-17 OPENS.
What happens to MU-V-17 if D/P fails LOW?
Indicated level goes UP → MU-V-17 CLOSES.
What happens to MU-V-17 if the reference leg lowers?
D/P goes DOWN → Indicated level UP → MU-V-17 CLOSES.
What happens to MU-V-17 if localized heating occurs in the reference leg?
D/P goes DOWN → Indicated level UP → MU-V-17 CLOSES.
What happens to MU-V-17 during rapid RCS depressurization?
Off-gassing ejects water from reference leg → D/P goes DOWN → Indicated level UP → MU-V-17 CLOSES.
What is the output of MS-15?
Unit T Hot and Unit T Cold, sent to ICS for BTU Limits.
What is the output of MS-12?
Loops A & B average, output is console digital Tave sent to ICS for Rx Control.
What happens to Tave when there are fewer than 4 RCPs?
AUTO swaps to the loop with more flow.
What is the impact of a Rx Trip on loss of MFW?
RCS pressure decreases, temperature increases, OTSG levels fall, and SCM lowers due to the temperature rise.
What is the approximate uncompensated pressurizer level?
Approximately 150 inches.
What happens to pressurizer temperature and saturation temperature during an insurge?
Liquid temperature decreases, and Tsat increases due to bubble compression and pressure increase.
What happens to indicated pressurizer level during a reference leg leak?
Indicated level goes up, but actual level goes down.
