Exam 8 prep Flashcards
CPC, CEDMCS, ERFDADS, Plant annunciator
1
Q
State the following trip setpoints for CPCs:
DNBR
LPD
Quality Margin
RCP speed
A
- DNBR: <1.34 Higher is better! Trip on LOW DNBR
- LPD: >21 kw/ft Lower is better! Trip on HI LPD
-
Quality margin feeds into the DNBR trip line after the DNBR calaculation
- Trips based on saturation in the outlet plenum
- RCP speed: <95% will trip the DNBR and LPD channels to protect against a 4 pump loss of flow event because the calculation isn’t fast enough
2
Q
How does the RCP speed trip affect DNBR and why?
A
- DNBR receives a 0.1 multiplier thereby lowering DNBR to trip levels no matter what input.
- This happens every 50 msecs
3
Q
What does DNBR and LPD protect against in the most limiting channel?
A
- For DNBR in most limiting channel it protects against clad damage
- LPD protects against fuel damage
4
Q
What will cause a CWP - CEA withdrawal prohibit?
A
- PCRDL
-
CWP’s (CEA Withdrawl Prohibit)
- Pressurizer pressure (high) pre-trip (2 out of 4)
-
CPC pre-penalty (2 out of 4)
- Sub-group to group deviation 5 inches
- PSCEAs < 30” withdrawn
- < 7.5” between groups (Out-of-sequence)
- Not at the top or bottom of the core (+/- 10”)
- Reactor power cutback is set
- DNBR pre-trip (2 out of 4)
- LPD pre-trips (2 out of 4)
5
Q
What are the power supplies to each CPC channel?
How is a rx trip prevented on energizing a CPC channel?
A
- CPC’s provided by power by its associated PN bus
- Prior to energizing a CPC channel need to BYPASS all parameters to prevent inadvertent trips.
6
Q
What parameters make up the core ASI calculation?
A
- Core ASI (20 segments)
- Calculated by:
- Excore signals
- Shape annealing
- Target CEA positions
- Temperature Tc (For Rod Shadowing)
- Rod Shadowing
- Calculated by:
7
Q
Explain the rule of 51 as it pertains to core ASI and CPCs.
A
-
Rule of 51
- On power going up @ a sum of 51% between the three ex-cores ASI shifts from a canned (constant) value for hot pin ASI to actual calculated ASI
- ~17% a detector (because: Math)
- On power going up @ a sum of 51% between the three ex-cores ASI shifts from a canned (constant) value for hot pin ASI to actual calculated ASI
8
Q
How is core ASI value affected on a rx shutdown from 100 % power?
A
On power going down @ a sum of 45% between the 3 ex-cores ASI shifts from a calculated value of ASI to a canned hot pin ASI value
9
Q
What calculates the AZ tilt for the core?
A
- Calculated by COLSS ONLY
10
Q
How is AZ tilt used in CPC and what is an indication that this value is no longer valid?
A
- Input into to CPC is an ADDRESSABLE CONSTANT
- Uses this constant value in calculations no matter what
- The only way we know this value is no longer good is a control room alarm initiated by COLSS
- Which at this point the constant is no longer considered conservative so a new conservative constant must be entered
11
Q
How is Tcold used in CPCs and what is talked about later?
A
- Tc uses (each CPC gets 2 of them from opposite loops)
- Minimum of the 2 goes to shadowing factors for ex-cores
- Maximum of the 2 goes to DNBR calculation
- Aux trip
- ≤ 505F or ≥ 590F
- Other things talked about later
12
Q
What are the LPD penalty factors and parameters?
A
CRAP
- CEAC Penalty Factor
- Radial Peaking Factor
- Axial Peaking Factor
- Power (max)
13
Q
What are the DNBR penalty factors and parameters?
A
CRAPFMP
- CEAC Penalty Factor
- Radial Peaking Factor
- Axial Reaking Factor
- Power Max
- Flow
- Max Tcold
- Pressure
14
Q
How is DNBR calculation performed and updated?
A
- DNBR Calculation
- Static DNBR (Every 2 secs)
- Baseline DNBR calculated using Calibrated Ex-core
- Update DNBR (50 msecs)
- Changes Static DNBR by updating parameter info
- Flow Update (50 msecs)
- Worst case for DNBR so it’s the fastest
- Static DNBR (Every 2 secs)
15
Q
Concerning CEACs, how are penalty factors applied?
When is a penalty factor not applied by CEAC?
Which deviation is worse?
A
-
Penalty factors start when a CEA is misaligned > 9”
- NO PENALTY FACTORS when within 10” of the top or bottom of the core
- Magnitude of the penalty factor depends on the following:
- Direction of deviation (out is much worse guaranteed immediate trip)
- Magnitude of deviation
- Type of rod (P.S., 4 finger, 12 finger)
16
Q
How is the CEAC penalty factor applied and why?
A
- Once the deviation occurs an initial penalty factor is applied then over the next 6 hours the penalty factor will go up to its maximum value (Xenon Redistribution penalty factor)
17
Q
List the AUX trips associated with CPCs.
A
PAT the VIP
- Processor fault
-
Assym steaming
- 20-50% S/P ramps from 35F – 20F
- 50-80% S/P ramps from 20F – 15F
- Protects against a closure of both MSIVs on the SAME generator at power
- Thot Sat.- within 19F of saturation
-
VOPT
- Rate of setpoint change 1%/min up and 16.67%/min down
- Step change: 8%
- High power: >110%
-
Input parameters
- Tc: 505F – 590F
- ASI: -0.5 – +.05
- PZR pressure: 1860 – 2388 psia
- Pumps - Less than 2 rcps running
18
Q
ON the CPC power display,
What is displayed in red, green and when does the CEA deviation light come on?
A
-
Indications:
- Calibrated linear power: Red Pen
- Excore linear power: Green
- CEA Deviation light: Comes in @ 5.5” deviation of CEAs within a group
19
Q
When RCS is > 300F, a loss of CEDM cooling requires CEDMs to be de-energized within how many minutes?
A
- RCS temp >300F or CEDMs must be de-energized within 40 minutes on a loss of cooling (in containment)
20
Q
State the operating characteristics of the MG sets associated with CEDMCS.
A
- 200 kW
- Each powered from NGN-L03 & NGN-L10
- Converts 480VAC to 240VAC
- If only 1 MG Set energized then CEAs must be moved in Manual Individual ONLY. Prevents overloading the MG
- MG have flywheels that maintain power and frequency for up to 1 second for power transients
- On an SPS trip MG set contactors are opened along with RTSG breakers for redundancy
21
Q
What do the UV coils de-energize at and what signals are sent out because of them?
A
- You must have 1&2 or 3&4.
- De-energize at ~ 180 VAC on a reactor trip they send signals to:
- MT/EHC – Initiates a turbine trip when the reactor is tripped
- DFWCS – Initiates RTO logic
- SBCS – Used in quick open block logic
- ERFDADS – Indication of reactor status
- SRP Multiplexer – SRP notification of unit trip
22
Q
What is used to prevent CEDM coil burnout when CEAs are stationary?
A
Lower amount of current than when moving CEAs. This helps prevent coil burnout.
23
Q
How is CWP - CEA Withdrawal Prohibit - bypassed when CWP is in?
A
- “CWP/B” Switch allows a CWP bypass must continuously hold it down while moving CEAs
24
Q
What are the different modes of operation and how are CEAs moved in each?
A
-
Modes of Operation:
- Auto Sequential: RRS control CEA motion
- Manual Sequential: Joystick moves Groups of CEAs in a sequential order
- Manual Group: Moves selected group
- Manual Individual: Moves just a selected CEA
- Standby: Blocks all rod motion (Except trip or RPCB)
25
How is the operator alerted to an Out of Sequence condition with CEAs?
Can this alarm be in fast flash?
* **CEA Tech Spec Violation**
* Annunciator: **Comes in if group motion is “Out-of-sequence”** according to the Plant Computer. This is if overlaps are not correct between regulating groups
* **This alarm can be in fast flash(this is not PDIL alarm).**
26
What will cause CEDMCS trouble alarm to come in?
* **CEDMCS TRBL**
* Continuous CEA motion
* Continuous Gripper High Voltage
* Any sub-group on the **hold bus** (also get an **SMA** LED on local panel)
* MG set problems
27
Describe the CEA movoement including what each pulse does and the available speeds, when they can be moved and the reed switch locations.
* **CEA movements**
* Each Pulse moves the CEA **.75”**
* Movement:
* Can go in @ **30”/min** **or 3”/min in AUTO**
* Can go in or out @ 30”/min in MANUAL
* Can go out @ **ONLY 3”/min when in AUTO SEQUENTIAL**
* Reed Swtiches are located **every 1.5”**
28
What heights have unique reed switches in CEDMCS?
* Special reed switches
* **0”** Rod drop contact (lights up the mimic)
* **Resets the Pulse Counters**
* **1 step** (.75”) Lower Electrical Limit **LEL**
* **200 step** (150”) Upper Electrical Limit **UEL**
* **Need to remember REED SWITCHES feed these**
29
Describe both UGS and LGS.
* UGS – Stops all Outward CEA motion when in group mode
* LGS – Stops all Inward CEA motion when in group mode
* Both these are bypassed by moving rods individually
30
What is AWP - Automatic Withdrawal Prohibit - and what will insert an AWP signal?
* **AWP** (Automatic Withdrawl Prohibit)
* Prevents automatic withdrawl of CEAs from RRS or SBCS
* **RRS:** Tavg \> than Tref by 6F
* **SBCS:** When there is a Steam Bypass Demand Signal
* TURB BYP DEMAND Annunciator
31
What is AMI - Automatic Motion Inhibit - and what signals will actuate it?
* **AMI (Auto Motion Inhibit)**
* **RRS** (every parameter must have average selected in RRS)
* **TLI:** 5% deviation between TLI signals
* **Control Channel:** 5% deviation between Control Channel
* **Tavg:** 5F deviation for Tavg signals (Loop 1 & 2)
* **SBCS**
* **\<15% reactor power**
* When Rx Power is \< the AMI setpoint **OR** \< the SBCS availability plus TLI (TLI has to be \>15%)
32
What is CWP - CEA Withdrawal Prohibit - and what signals will actuate it?
* **CWP** (CEA Withdrawl Prohibit)
* **HI PZR PRESS CH PRE-TRIP** (any 2 of 4 Channels)
* **LO DNBR CH PRE-TRIP** (any 2 of 4 Channels)
* **HI LPD CH PRE-TRIP** (any 2 of 4 Channels)
* **REAC PWR CUTBACK**
* CEA misalignment generated from CPC's/CEAC's:
33
Where are the RTSG breakers operated from?
* RTSG breakers
* **Opened from:**
* B05
* Locally
* PPS Cabinets
* SPLA Cabinets
* **Closed from:**
* PPS Cabinets
* Locally
* SPLA Cabinets
34
How does a loss of NNN-D11 and/or NNN-D12 affect CEDMCS?
* Loss of NNN-D11 & 12
* Can withstand a loss of one but not both…..if both, rods go in
35
How does a loss of PNC-D27 or a loss of PND-D28 affect CEDMCS?
* Loss of PNC-D27
* ¾ rod bottom lights come in **and resets the pulse counters for the effected CEAs**
* Loss of PND-D28
* ¼ rod bottom lights come in **and resets the pulse counters for the effected CEAs**
36
What event led to the NRC requiring a system like ERFDADS at each nuclear plant in the country?
TMI
37
State the power supplies to ERFDADS and which one requires manual transfer.
* **Power Supplies:**
* Primary: **NKN-M45**
* Backup: **NHN-M08**
* Backup: **NHN-M72** (requires manual transfer)
38
What do the colors in ERFDADS represent?
* **Colors:**
* Green: Good Data
* Magenta: Bad Data (out-of-range or loss of data link)
* White: Suspect Data
* Yellow: Exceeded a **Level 2 alarm setpoint**
* Red: Exceeded a **Level 1 alarm setpoint**
* Cyan: Manually inputted data
39
Concerning ERFDADS, what are the different levels of alarms?
* Alarms:
* Level 1: **Preset alarms**
* Level 2: **Operator input alarms**
40
Concerning ERDS, how soon must ERDS be activated?
What does ERDS provide?
* **ERDS**
* Activated within **1 hour of declaring an ALERT or higher.**
* Direct line to NRC
41
Concerning the leak rate detection portion of ERFDADS, how soon after a leak starts is the calculation considered accurate?
* **Leak Rate Detection**
* **CALCULATION of leak rate will not be accurate until 7.5 minutes AFTER the leak has started**
42
Concerning the P/T curves, what do the different colors mean?
* The button will indicate grey when normal
* Changes to **yellow** when **NPSH is exceeded**
* Changes to **red** when **subcooling is exceeded**
43
Concerning ERFDADS, how is data stored and archived?
How is this different for PTARS?
* Done in 14 hour loops
* ERFDADS
* **1 sec snaps on a continuous 14 hour loop**
* PTARS
* **0.1 sec snaps on a continuous 14 hour loop**
* * A **16 day file taking 1 min snaps is also stored.**
44
How is data stored surrounding events associated with a Rx trip?
* **When a trip occurs it saves the data from 2 hours prior to the trip and records all data from 12 hours after the trip and then saves this to the STANDBY file.**
* From there the data can be moved to a SECONDARY file location and transferred to a .DAT file.
45
What does a fast flashing first trip annunciator tell the operator?
What if that parameter is bypassed and is in a tripped condition?
Why is this a problem?
* First trip annunciator **flashes faster than others**
* **If a parameter is bypassed** AND **is in a tripped condition** the first out annunciator still sees that as a trip signal. This means that if an **additional channel on the same parameter trips the first out annunciator will alarm.**
* This can also mask the real reason for the trip
46
What are the power supplies for the Class annunciators?
What is the rule of 58?
* Class Annunciators
* **PKA-D21 & PKB-D22**
* **Rule of 58!** (Non-class annunciators) **Normal seeking transfer switch**
* RKN-CO1 ( ½ the annunciators)
* **NKN-D43 w/ NNN-D15 backup**
* RKN-C02 ( ½ the annunciators)
* **NKN-D42 w/NNN-D16 backup**
* **THERE WILL BE A POWER LOSS QUESTION. Really understand how things like a SIAS w/ a LOOP combined with a loss of DC power effects this. Remember NNN-D16 in Unit 3 is not SIAS load shed.**
47
What functions do the following buttons perform?
Alarm Ack:
Flasher Reset:
Lamp Reset:
Test:
* **Buttons:**
* **Alarm Ack**
* Ack alarms on all boards. Leaves in fast flash
* Windows in fast flash will **not** provide audible if another alarm comes in on same window
* Only button that affects all boards
* **Flasher Reset**
* Changes fast flash to slow flash (if alarm is clear)
* Changes fast flash to locked in (if alarm still in)
* **Lamp Reset**
* Changes slow flashing to off
* **Test**
* Test all alarm windows on associated board
48
What do the following sounds indicate to the operator with regard to RK system?
* **Sounds:**
* **Repeating Chime:** Indicates alarming condition
* **Single Chime:** Alarming condition returning to normal
49
How does a loss of NKN-M45 during a SIAS affect Unit 1 and 2 RK vs Unit 3 RK?
* Loss of NKN-M45 and SIAS = **loss of all RK (Units 1-2);**
* **loss of half of RK (Unit 3)**
