.AR SE-ExCores NI's (Welch's Highlighted Notes) Flashcards
1
Q
Start-up Channels (S1/S2)
- What are the power supplies?
- How many decades of power… in CPS?
- what type of proportional counters are they? In what part of the core are they located?
- Pre-Amplifier
- It does what?…
- Signal Processing Drawer
- Power supplies and electronics to condition what?…
- Where does signal from pre-Amp goes where?…
- Discriminator compares it with what?… What happens if the pulse height exceeds this setting?
- Eliminates what signals?… & allows only what to pass?…
- Where is the output sent to?…
A
Start-up Channels (S1/S2)
- Power: NNN-D11 and NNN-D12 (120Vac)
- 5 decades of power (10E-9% to 10E-4% or 1 to 1e5 CPS)
- BF3 proportional counters (located mid-plane of the core)
- Pre-Amplifier
- Amplifies the NI output to a signal strength that is capable of reaching the MCR. Distribute high voltage to anodes of each detector.
- Signal Processing Drawer
- Power supplies and electronics to condition the output from the detectors.
- Signal from pre-amp goes to the Discriminator and Driver (Pulse Counting Circuit).
- Discriminator compares it with a threshold. If the pulse height exceeds this setting, the signal will pass.
- Eliminates gamma signals and noise, allowing only those pulses generated by a neutron to pass.
- Output sent to log (indications / bistables) and audio count rate circuits.
2
Q
{Start-up Channels (S1/S2)}
- High CPS Bistable
- # of CPS? – … is this an MCR annunciator?
- Should the High voltage be turned ON or OFF?… Why?…
- # of CPS? – … is this an MCR annunciator?
A
{Start-up Channels (S1/S2)}
-
High CPS Bistable
- 10,000 CPS – MCR annunciator
- HI CPS button/light on cabinet
- High voltage should be turned off to the detectors to extend the life of the detector.
- Startup High Voltage Low bistable
- HV LOW button/light on cabinet, < 1500 Vdc
- Control / Startup Channel 1 (2) Selector Switches (located on B04)
- High voltage to SU channel is OFF when Control channel is selected.
3
Q
Boron Dilution Alarm System (BDAS):
- Uses signal from where?…
- How is the setpoint lowered? To keep the setpoint where?…
- When is the Alarm disabled (…when < #? cps)?…
- As power rises, does the setpoint change?…
- RESET – Allows what?…
- FLUX/SETPOINT button – selects what?…
- Testing Mode:
- Is BDAS OPERABLE in test mode?
-
What happens if you Rapidly depress the FLUX / SETPOINT switch?
- In setpoint mode, press # times in # seconds
- In flux mode, press # times in # seconds
A
Boron Dilution Alarm System (BDAS)
- Uses signal from startup channels.
-
Setpoint is automatically lowered to keep it at 1/3 decade above the actual neutron flux levels.
- Alarm is disabled when < 5 cps (minimize nuisance alarms)
- As power rises, the setpoint does not change
- RESET – allows alarm reset and setpoint reset to 1/3 decade above current flux
- FLUX/SETPOINT button – selects which value is displayed
- Testing Mode:
- BDAS is inoperable in test mode
-
Rapidly depressing the FLUX / SETPOINT switch may cause BDAS to enter test mode
- In setpoint mode, press 3 times in 3 seconds
- In flux mode, press 4 times in 3 seconds
4
Q
LCO 3.3.12 Boron Dilution Alarm System (BDAS)
- How many channels operable in Modes 3-6?
- 1 Channel INOP… Actions?
- 2 Channels INOP… Actions?
- if not met, then what?
- Safety analysis assumptions to mitigate consequenses of an inadvertent boron dilution event:
- Modes 3-5, Alarm at least # minutes prior to criticality?
- Modes 6, Alarm at least # minutes prior to criticality?
- What alarm capacity is required in MCR and prompt RESET time frame (
A
LCO 3.3.12 Boron Dilution Alarm System (BDAS)
- Two channels operable in Modes 3 – 6. (Required in M3 within 1 hour of entering the SR [≤ 2E-6%])
- One inoperable: immediately determine RCS boron
- Two inoperable: immediately determine RCS boron by redundant method (independent sample)
- If not met, immediately stop positive reactivity additions.
- Meets safety analysis assumptions to mitigate the consequences of an inadvertent boron dilution event.
- Alarm at least 15 minutes prior to criticality in Modes 3-5
- Alarm at least 30 minutes prior to criticality in Mode 6
- Alarm capability in MCR and prompt RESET (< 5 min per the ARP) of the alarm is required for operability.
5
Q
LCO 3.9.2 Nuclear Instrumentation
- How many OPERABLE channels in Mode 6?
- 1 INOP Channel? Actions?
- 2 INOP Channels? Actions?
- Each SRM must provide continious what?…
- Each SRM must have the capability to provide what?…
- Loss of audible… what happens?…Per LCO 3.9.2 does BDAS remain OPERABLE?
A
LCO 3.9.2 Nuclear Instrumentation
- Two SU Channel NIs operable in Mode 6.
- One inoperable – Immediately suspend Core Alts and positive reactivity additions.
- Two inoperable – Immediately take actions to restore
- Each SRM must provide continuous visual indication in the MCR
- Each SRM must have the capability to provide audible indication in both the MCR and CTMT via use of MCR switches.
Loss of audible makes both channels inoperable for LCO 3.9.2. BDAS would remain operable if only audible was lost
6
Q
Control Channels (C1/C2)
- Power Supplies?…
- 0-#? % power level?
- What kind of Uncompensated Ion Chamber (UIC)?
- How many detectors are there? At what core height?
- Outputs to where?
- …what do they have in common with SU Channels?
- Detector signals pass thru what?…
- Voltage signals are sent where?…
- Summer output then passes thru what?…
- Amplifier has a gain adjustment that is used to adjust what?…
A
Control Channels (C1/C2)
- Power: NNN-D11 and NNN-D12 (120Vac)
- 0-125% power
- Boron lined uncompensated ion chambers (UIC)
- 2 detectors (33% and 66% core height)
- Outputs to RRS and DFWCS
- Uses same signal processing drawer as SU channels
- Detector signals pass through a linear amplifier (SUB 1 and SUB 2). Converts the current signal to a proportional voltage signal.
- Voltage signals sent to a summer to develop an average power signal. (one failed = output drops by half)
- Summer output then passes through a CAL SUM amplifier creating a calibrated control channel power signal.
Amplifier has a gain adjustment installed that is used to adjust the power level to match calorimetric values.
7
Q
Safety Channels (A,B,C,D)
- range of % power?
- How many fission chambers per channel?…
- Allows measurement of what?
- Center fission chamber is also used as what?…
- How sensitive is it?…
- Detectors (What gas(es)? coated with what?)…
- Log power functions like which other channels?
- Where are the A & B channel pre-amps located? Why?
- Where does the actual Signal processing occur?
- Power supplies?:
- A: ? / B: ? / C: ? / D: ?
A
Safety Channels (A,B,C,D)
- 2E-8% to 200% power
- Each channel has three identical fission chambers vertically along the full length of the core.
- Allows measurement of the axial power shape (CPCs)
- Center fission chamber also used as the wide range (log) detector.
- Sensitive enough to detect neutron flux for 12 hours following shutdown.
- Detectors (Cylinder with nitrogen/argon gas, electrode coated with enriched U-235)
- Fission fragments strip the gas atoms of electrons. These electrons are proportional to the energy of the FFs.
- Electrons counted by the electrode.
- Log power functions like the SU channels.
- A & B channel pre-amps are located outside CTMT (PAM instrument, protected from the harsh environment)
- Signal processing occurs in the Plant Protection System (PPS) cabinets
-
Power (class 120 Vac):
- A: PNA-D25 / B: PNB-D26 / C: PNC-D27 / D: PNC-D28
8
Q
Logarithmic Circuit
- range?
- How many circuits are utilized to ensure an accurate indication?
- Lower 6 decades uses?…
- What happens when this begins to lose effectiveness?… (proper term name for this?)…
-
Log 1 bistable (> 10-4%): Provides a permissive permit what?
- Bypass is automatically removed when?…
- Alarm LIT until what?…
-
Log 2 bistable (≤10-4%): provides a permissive to permit what?
- Bypass is automatically removed when?…
- Conservatively set to what % level during initial startup?…
- Hi Rate of Change of Power alarm is?…(2.5 DPM). Reset where?…
A
Logarithmic Circuit
- 10 decade range
- Two circuits are utilized to ensure an accurate indication
- Lower 6 decades uses pulse height discrimination log count rate circuit.
- When this begins to lose effectiveness (saturate), a mean square variation circuit is used. (Cambelling)
-
Log 1 bistable (> 10-4%): provides a permissive to permit bypass of the high log power trip.
- Bypass is automatically removed when power lowers below the bistable.
- Alarm LIT until bypassed (Hi Log Pwr Lvl Byp Perm)
-
Log 2 bistable (≤10-4%): provides a permissive to permit bypass the DNBR and LPD trips (CPC trips).
- Bypass is automatically removed when power rises above the bistable.
- Conservatively set to 10-5% during initial startup.
- Hi Rate of Change of Power alarm (2.5 DPM). Reset at cabinet.
9
Q
Linear Circuit
- Consists of what?
- 3 sub-channels are independently sent where? why?
- 3 sub-channels are avereraged, what is this term called? Calibrated based on what?
- What happens if 1 detector fails? (output drops by?…)
- Output is sent to where?…which trip?
A
Linear Circuit
- Consists of 3 linear amp circuits and a two-stage summer circuit.
- Three sub-channels are independently sent to PPS for use in the CPC which provides low DNBR and high LPD trips.
- Three sub-channels are averaged (term SUM power). This signal is calibrated based on calorimetric.
- One detector fails = output drops by 1/3
- Output is sent to the PPS for use with the Variable Overpower Trip (VOPT).
10
Q
Safety Channel Controls - Back Panel (Log, rate and linear sections)
-
Log Calibrate switch. If not in Operate:
- Alarms? where?
- what 2 trips does it provide?
- Disables what relays?
- Disables what other relays?
- SImulates a %? log power signal to which system? This initiates what?… Can it be bypassed?…
-
Rate Calibrate and Test switches
- Initiates a trouble alarm if?…generates what 2 Rx Trips?
- What will the Linear and calibrate switches do?…
A
Safety Channel Controls - Back Panel (Log, rate and linear sections)
-
Log Calibrate switch. If not in Operate:
- Trouble alarm (locally on the drawer and in MCR)
- DNBR and LPD trips (unless bypassed on the PPS).
- Disables Log 1 and Log 2 bistable relays (Removing the bypasses of PPS)
- Disables rate bistable relay - initiates high rate of change of power annunciator (locally and in MCR)
- Simulates a 200% log power signal to the PPS that will initiate a high log power trip (trip can be bypassed on PPS)
-
Rate Calibrate and Test switches
- If not in operate (or OFF for test switch), initiates a trouble alarm and generates DNBR and LPD CPC trip in the associated channel (unless bypassed on the PPS).
- Linear calibrate and test switches will do the same.
11
Q
[…Not highlighted in Welch’s Notes]
- Trouble Lamp Pushbutton. Lit:
- @ what voltage level?
- other reasons for it?
A
- […Not highlighted in Welch’s Notes]
- Trouble Lamp Pushbutton. Lit:
- Low or High Voltage,
- Removal of a module (PC Card)
- Taking a calibration switch (LOG, RATE or LINEAR) out of OPERATE.
- Taking a trip test switch (LOG, RATE or LINEAR) out of OFF.
12
Q
NI Calibration
- Adjust indicated power (Control / Safety channels)… to match what?
- JSCALOR… normal or backup?
- NKBDELTC… normal or backup?
- Control channel calibration:
- Defeat input to which 3 systems?…
- need to adjust what?…
- Safety channel calibration:
- VOPT, Hi LPD, and Lo DNBR are placed in what? Where?…
- Raw excore signal is adjusted using what?… where?…
- CPC powers are adjusted how?….
A
NI Calibration
- Adjust indicated power (Control / Safety channels) to match the calorimetric power.
- JSCALOR is normally used (secondary calorimetric)
- NKBDELTC is used as a back-up (primary power)
- Control channel calibration:
- Defeat input to RRS, SBCS and FWCS
- Adjust gain potentiometer
- Safety channel calibration:
- VOPT, Hi LPD, and Lo DNBR are placed in bypass at PPS drawer.
- Raw excore signal is adjusted using the Excore Linear Calibrate pot on B05
- CPC powers are adjusted by changing addressable constants in the CPCs.
13
Q
Reactor Start-up and raising power
-
How many # CPS?: Startup Channels are turned off when?:
- How is this done? (3 steps performed)…
- 1x10-4% (Log 1): High Log Power trips are what?
- Perform NI calibration at what power level %? (prior to exceeding what % level)?…
A
Reactor Start-up and raising power
-
10000 CPS: Startup Channels are turned off after proper overlap on Safety Channel Log Power
- Selecting the Control Channels
- Depressing the HV PERMIT pushbutton
- Then selecting the Control Channel for the HIGH VOLTAGE indication.
- 1x10-4% (Log 1): High Log Power trips are bypassed after the permissive is received and before 10E-2%.
- Perform NI calibration at 17-19% (prior to exceeding 20%)
14
Q
Plant Shutdown
- Startup Channels are energized at what % level?
- Which MCR Board (B01-B07?)
- Where do you depress the HV PERMIT push-button?…
- … setup which circuit?…
- Ensure proper overlap between which channels?…
NI cooling
- Cooled by which Fans?
A
Plant Shutdown
- Startup Channels are energized at 2E-6%
- Selecting them on B04 selector switches
- Depressing the HV PERMIT push-button on the signal processing drawer.
- Setup the audio count rate circuit.
- Ensure proper overlap between the Safety Channels.
NI cooling
- Cooled by Reactor Cavity Normal Cooling Fans (CTMT HVAC)
15
Q
[…Not highlighted in Welch’s Notes]
LCO 3.3.1 RPS Instrumentation – Operating (Four channels required)
- VOPT (modes…)
- High Log Power level? (modes…)
- High LPD? (modes…)
- low DNBR? (modes…)
- 1 Channel INOP? Actions?
- 2 Channels INOP? Actions?
- One Auto Bypass removal bypass INOP? Actions?
- Two Auto Bypass removal bypass INOP? Actions?
- Log Channel INOP required entry into which condition? Why?
- …Must restore it prior to entering M#? following next M#? entry?…
A
[…Not highlighted in Welch’s Notes]
LCO 3.3.1 RPS Instrumentation – Operating (Four channels required)
- Variable Over Power (VOPT)
- Modes 1 and 2.
- Log Power Level – High
- Mode 2 (Note allows bypass > 1E-4%, must un-bypass automatically)
- Local Power Density – High
- Modes 1 and 2 (Note allows bypass < 1E-4%, must un-bypass automatically)
- DNBR – Low
- Modes 1 and 2 (Note allows bypass < 1E-4%, must un-bypass automatically)
- One inoperable – trip or bypass in 1 hour
- Two inoperable – trip one and bypass one in 1 hour
- One auto bypass removal inoperable – disable bypass OR place in trip or bypass in 1 hour
- Two auto bypass removal inoperable – disable bypasses OR trip one and bypass one in 1 hour
- Log channel inoperable requires Cond C entry due to Log 1 and Log 2 being inoperable.
- Must restore it prior to entering M2 following next M5 entry.
