Term
SEC
(Safeguards Equipment Controls)
Purpose |
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Definition
Determines the need for SI and /or Blackout safety equipment
Loads the equipment onto the 4KV Vital Buses
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Term
SEC
Safeguards Equipment Control
Solid State Protection system
Design Basis |
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Definition
1. Starts all Equipment required to keep the plant in a safe condition during: SI/BO or Both.
2. Shutdown can be achieved under all postulated AB conditions with at least 1 EDG available.
3. Each unit has a seperate and independent Power source to feed the SEC
4. Each EDG has their own SEC for all SEC Modes |
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Term
| Power for the SEC is supplied from? |
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Definition
A cabinet: "A" 115VAC VIB
B cabinet: "B" 115VAC VIB
C cabinet: "C" 115VAC VIB
SEC Power loss=No EDG auto Start
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Term
Definition of undervoltage...
Definition of Degraded Voltage...
Definition of Blackout... |
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Definition
UV: Bus at or below 70% of Nominal Voltage
DV: Bus Voltage at or below 95.1% of Nominal Voltage (> 13 sec)
BO: Undervoltage condition on at least 2 of 3 4KV Vital Buses |
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Term
| Name the SEC Modes , Causes and Sequencer. |
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Definition
Mode I = SI
Mode II = BO (SEQ 1)
Mode II* = BO Single Bus (SEQ 1)
Mode III = SI + BO (SEQ 2)
Mode IV= SI + Single Bus UV/DV (SEQ 2) |
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Term
| What actions are common during ANY SEC Mode? |
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Definition
EDG Breaker Opens
EDG swaps to Isochronous Mode
SW to the TGA is Isolated via the SW20s or SW26 within 40sec
Chill water to PACUs and Chemistry RM Coolers Isolate
Lock out of "Manual Control" of all bus loads until Seq. is complete and SEC reset |
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Term
| Name the Primary Service Water Pumps for SEC actuation. |
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Definition
SW21, SW24, and SW25
Alternate pumps will start 5 seconds later only if the primary pumps fail to start. |
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Term
| In what SEC mode are the CCW Heat exchangers Isolated from Service Water? |
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Definition
Mode III
By Closing 11/21SW122, 22SW122, 1SW376 and 1SW380 |
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Term
| What restricted automatic Mode changes are allowed by the SEC without an operator reset of the SEC? |
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Definition
Mode I to Mode III
Mode I Mode IV
Mode II to Mode III
Mode II* to Mode IV |
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Term
| State the actions of an automatic Mode Change... |
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Definition
1. SEC Stops SEQ.
2. Sequencer Currently in use resets.
3. All Loads previously started are shed and EDG Breaker opens.
4. EDG breaker closes and new sequenced loading for the mode begins.
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Term
| Sequence failure during Mode III and the EDG fails to start or EDG trips during loading... What actions must be taken to reset the SEC? |
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Definition
The SEC can NOT be reset until the SI signal is either reset or blocked and voltage is restored to the 4KV Vital Bus.
Restoration of the Vital Bus is NOT possible unless the SEC is De-energized. |
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Term
| Configuration Duration for a SI reset is? |
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Definition
| at least 74 seconds and the SEC must be reset. |
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Term
| When can the SEC be reset? |
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Definition
1. SI is reset(74 seconds min.) or Blocked.
2. Re-energized associated 4KV Vital Bus.
3. SEC Loading Sequences completed for 10 sec. |
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