4505 Flashcards
What do the FSGs Protect?
Core Cooling
Containment
SFP Cooling
What is the purpose of the Deep DC Load Shed and how long do we have to do it?
Extends battery life
Within 1 hour of declaring ELP
What is the 500 kW Power preferred to provide power to Bus 11D/11B (21D/21B)?
It will give us batteries
Why is reflux cooling a problem?
It will result in pockets of diluted water forming in the RCS Legs that could cause a recriticlity issue
What is indicative of a #2 Seal failure on a RCP?
RCP Seal #1 Leak off Flow Lowering
AND RCP Seal #2 Standpipe his level alarm LIT
What conditions require a Reactor Trip during Excessive RCS Leakage?
PRZ Level not maintained with 2 CCPs
Containment Pressure is approaching 1 psig
VCT Level cannot be maintained
At what frequency must we trip the Reactor?
58.2 Hz
OR after 30 mins if below 59 Hz but about 58.2 Hz
What is the set point for degraded bus voltage?
113.2 Volts for 9 seconds on T11A/D
How long before transfer on degraded bus voltage if there is a SI or Lo-Low SG Level?
When on UATs, just the original 9 seconds
How long before power is transferred from UAT to RAT on degraded bus voltage?
9 seconds of condition + 90 Seconds to Fast Transfer to the RATs
How long will it take to transfer from the UATs to the EDGs on degraded bus signal with no SI / Low Low SG Level?
9 seconds to sense, 90 seconds to the RAT, 21 secs if degraded bus voltage still exists
How long will it take to transfer power to the EDGs if on the RATs and a degraded Bus Voltage problem exists?
111 seconds (90 seconds + 21 seconds)
If T11A senses degraded bus voltage, is it the only one that will transfer to a new power source?
No
Although sense on the pump busses, it also strips off the other bus on the same train.
What are the auto actions for DBV?
Sensed on pump bus for the train. When on the UATs, will result in a transfer to the RATS. If not, the next 21 seconds of the DBV will result in opening the RCP bus tie breaker.
DBV when already aligned to the RATs will open the RCP bus tie breaker at the 111 second point
What decides the SG Pressure input to SG PORV?
Which every Steam Pressure Selector is selected
What decides the SG Pressure input to the Steam Flow Density Compensation?
Which ever Steam FLOW selector is selected
Which forms should be completed before making notification to the NRC?
Att 11 - NRC Notification
&
Data Sheet 2 - Plant Status
How long do you have to complete notification to the MSP and BCSD?
15 mins
How is the notification time to the MSP and BCSD measured?
Begins when SM/STA agree on the classification
Ends when EMD-32 data has been read to both agencies
Which SED Duties can NOT be delegated?
Classification of the emergency
Directing the notification of offsite officials
Approval of PAR to offsite emergency management agencies
To utilize EP, why must you have a dead bus?
30 degrees out of phase
To power a T bus from EP, it requires the respective bus to be deenergized. We are intentionally giving ourselves a Load Shed on that Bus. With this load shed signal present, how can we close the EP breaker?
EDG Output breaker is placed in PTL, which will disable that load shed
What condition must be satisfied to enable BOTH auto and manual closure of the EDG Output breaker?
EP Breaker must be open
The Engineered Safety Electrical System is designed to ensure power is available to:
ALL safety equipment during design basis accidents
What happens if normal Power to the CRID is lost?
Auto Transfers to its alternate 600 VAC Power supplie
What is the normal power supply to the CRID Inverters?
250 VDC
What happens if normal power is lost to the CRID Inverter and then it returns?
Auto Transfer back to its normal source of power after a 30 second time delay. It will transfer to alternate one more time and stay there until the auto retransfer lock out is reset.
What is the operability status of the CRID Inverters if they are not being fed from the 250 VDC normal power supply?
INOPERABLE
What is the Operability status of the CRID Buses when powered by the alternate 600 VAC power supply?
OPERABLE
What are the associated 600 VAC Power supplies for each CRID Distribution Panel?
CRID 1 - C
CRID 2 - D
CRID 3 -A
CRID 4 - B
What is a backup power supply to the CRIDs?
CRP-3
What will cause a Loadshed?
2/3 on EACH T bus at 94 (93) Volts, w a 2 second time delay
What will cause a Load Conservation?
Load Shed with a SI or CTS Signal
What happens on a Load Conservation?
LO Cooler Motor Operated Valves close
Containment NESW Valves Close: CUVs, CIRs, RCP air (NOT CLVs!!)
Unit Valve to Misc Header closes
NESW Pump trips if there is a CTS Signal (restart after 75 secs after going to lockout)
When would the degraded Bus Voltage actuate load shed relays in 9 seconds?
SI Exists
Or
Low-Low SG Level in a single SG
Which Load is shed by the Load Conservation energized by LOOP and CTS?
NESW Pump
What actions would you take if you noted that 69kV was showing a voltage of 110 V on EP Bus 1 while supplying power to T21 D during Mode 6?
Adjust Load. Remove loads on T21D to improve voltage
What condition would cause a load conservation signal to be generated for the Unit 2 CD EDG?
Train A SI with LOOP
What are the advantages of using ES-3.1, Backfill?
Minimizes Radiological Releases.
What are the advantages of using ES-3.2, Blowdown?
Minimizes Radiological Releases and Boron dilution
Why would we want to use ES-3.3, Steam Dump
Fastest of the 3 cool down methods
When wanting to avoid an environmental release, which cool down method would we use: ES-3.1, 3.2 or 3.3?
ES-3.1, Backfill
Which cool down method cools down the RCS and Depressurizes the RCS Concurrently: ES-3.1, 3.2 or 3.3?
ES-3.1, Backfill
When using ES-3.2, Cooldown using Blowdown and 3.3, Cooldown with Steam Dump, how is leakage between the ruptured SG and the RCS Controlled?
Cooldown is done first. The ruptured SG level is monitored and adjustments are made to RCS pressure and charging to keep it constant
If there are multiple ruptured SGs, which procedure should we be in?
E-3, SG Tube Rupture
What are some conditions that require a transition to ECA-3.1?
- SGTR with LOCA
- Faulted, Ruptured SG
- SGTR with ALL SG Stop valves failing to close
- Minimum dP (250#) between ruptured and intact SGs can’t be maintained.
Why would we transition from ECA-3.1, SGTR with loss of RC - sub cooled recovery desired to ECA-3.2, SGTR with loss of RC- saturated recovery desired?
- RWST level is low with NO corresponding rise in containment sumps
- Ruptured SG Level is HIGH. SG Overfill is imminent
In ECA-3.3, SGTR without PRZ Pressure Control, the first major action is to restore pressure control What must occur to proceed to the SI Termination steps in this procedure and stop waiting for pressure control?
Ruptured SG Level >67% and PRZ Level > 21%
ECA-3.3, SGTR without Pressurizer Pressure Control directs operators to adjust charging flow to maintain sub cooling, NOT to restore PRZ Level. WHY?
Raising PRZ Level would raise RCS Pressure, which would raise RCS Leakage
What happens to the Thermal Utilization Factor (f) as fission product poison concentrations go up?
Thermal Utilization Factor LOWERS because of competition. This causes negative reactivity
What is a fission product poison?
A fission product that has a substantial neuron absorption cross section and does not fission
What makes a good poison?
High abundance and large barns
Which of the 3 (fission, decay, neutron absorption) are contributors to production and which contribute to removal?
Fission - Production
Neutron Absorption - Removal
Decay - Both
What percentage of Xe-135 production is caused by direct fission?
5%
What percentage of Xe-135 production is caused by I-135 decay?
95%
What happens to Xe-135 concentric on a unit trip after operating for 200 days at 100% power? Why?
Rise due to iodine decay in the core
What type of decay chain can products Xenon-135?
Beta - decay of Te-135
Why is Xe-135 a major reactor Poison?
High production from fission and Large absorption cross section
What percentage of Xe removal is from decay?
20% from Beta - decay
What percentage of Xe removal is from burnout?
80%
Approximately how long will it take fro equilibrium Xenon to be reached?
40 hours
How does Xenon compare at 100% power versus 50% power?
50% power Xenon is approximately 80% of what it is at 100%
How does Xenon compare at 25% power in comparison to 100% power?
25% power equilibrium is about 1/2 of what it is at 100% power
How long does it take to reach the Xenon Peak after a power change?
Square Root of the % change in power
What effect does core age have on Xenon?
Xenon concentration Lowers, but Xenon Reactivity becomes more negative due to less competition
What can affect both the production and removal of Xe-135?
Thermal Neutron Flux Level
How will the Xenon-135 production terms (direct fission and decay of iodine) change when a reactor is quickly rambled up to 100% power from a steady state 50% power?
Fission Term increases and Iodine Decay term increases as iodine builds in
Which Reactor will have a Higher Peak when tripped?
Reactor at 50% power
Reactor 100% power
Higher Peak will be the reactor at 100% power.
How much more water is required to dilute 1 ppm at the EOL compared to BOL?
10X more water is needed at EOL
Following a refueling outage, what is responsible for the majority of the rapid initial decrease in critical boron concentration?
Fission Product Poison Buildup
Why must there be a large increase in full power boron after refueling compared to EOL?
Reactivity from fissionable fuel in the core at BOL is greater than EOL
During a 6 month period of full power operation, the Reactor coolant boron concentration must be decreased steadily to compensate for _____?
Fuel Depletion and build up of fission product poisons
As reactor coolant boron concentration is reduced, what happens to boron reactivity worth?
It becomes more negative due to decreased number of boron molecules in the core
The amount of boric acid required to increase the coolant boron concentration by 50 ppm at BOL is approximately _____ as the amount required to increase boron concentration by 50 ppm at EOL.
The same!!!!!
Xenon poisoning in a reactor core is most likely to prevent a reactor startup following a shutdown from _____ power and the ____ of life.
High Power
End of Life
