Term
CS
Describe ECCS design criteria. |
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Definition
-PCT < 2200F.
-Max clad oxidation < 17% total thickness.
-H2 generation < 1% max theoretical.
-Maintain coolable geometry.
-Maintain long term cooling. |
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Term
CS
Describe the CS flowpath. |
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Definition
-Takes suction from TORUS ring header through normally open suction valve (MO-1741/1742).
-Through the pump and splits between minimum flow line back to TORUS or;
-To a normally open outboard (MO-1751/1752 and then normally closed inboard (MO-1753/1754) injection valves.
-Through a check valve in the drywell to the 11 or 12 spray injection header. |
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Term
CS
Describe the test flow path. |
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Definition
-From TORUS ring header through normally open suction valve (MO-1741/1742) through pump.
-Through minimum flow line back to TORUS or;
-Through a normally closed (MO-1749/1750 test line and an orifice back to TORUS. |
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Term
CS
Describe the loop flush flow path. |
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Definition
-Takes suction on TORUS ring header through normally open suction valve (MO-1741/1742) through pump.
-Then flows through the min flow line, test line, and injection lines.
-Min flow line and test line return to TORUS, injection line goes into core spray nozzles. |
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Term
CS
Describe the CS pump interlocks. |
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Definition
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Term
CS
Describe the CS spargers. |
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Definition
-Designed to spray coolant directly above fuel inside the core shroud using two SS spargers via 204 nozzles in 2 semi-circles for each loop.
-A Loop sparger at 27” above TAF.
-B Loop sparger at 17” above TAF. |
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Term
CS
Describe the sparger leak detection system. |
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Definition
-Pressure switches measure the D/P between above the core plate and the CS discharge line downstream of the testable check valve.
-If there was a break between the shroud and vessel, the discharge line pressure will be the same as downcomer pressure.
-This is lower than the pressure inside the shroud.
-Alarms at 4 pounds less than installed differential pressures.
-11 core spray @ -58 In WC.
-12 core spray @ +3 In WC. |
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Term
CS
Describe the suction strainers. |
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Definition
-Screened 1/8” openings to prevent plugging spray nozzles.
-Suction sized to allow full RHR and CS flow even with one screen fully blocked.
-Suction flow limits based on torus water level, water temperature and torus/drywell pressure. |
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Term
CS
Describe any precautions to ensure suction valve is open. |
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Definition
| Has a keylock operator on C-03. |
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Term
CS
Describe when the CSTs are used as a suction source. |
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Definition
-Used for system flush and sized for full flow testing from CST to RPV.
-Also used for flood-up of RPV during RFO’s. |
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Term
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Definition
-Each rated at 3020 gpm, discharge head of 375 psig.
-Rated flow within 38 seconds of receiving initiation signal.
-Minimum flow required is 2835 gpm, with 135 gpm used to account for leakage paths and LPCI flow offset, when reactor pressure 130 psid > drywell pressure (Tech Spec).
-Short term minimum flow (2 hours or less in 24 hours) is ≥ 850 gpm (1500 gpm per B.03.01-05).
-Continuous minimum flow (in excess of 2 hours) is ≥ 1275 gpm (2000 gpm per B.03.01-05). |
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Term
CS
Describe the AC interlock with CS. |
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Definition
-Discharge of pump sensed for > 100#.
-Input into ADS logic to ensure a LP ECCS pump is running. |
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Term
CS
Describe the minimum flow line rated flow. |
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Definition
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Term
CS
Describe pump discharge pressure protections. |
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Definition
-Runout prevention orifices downstream of pump.
-Relief valves set at 500#. |
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Term
CS
Describe test line valve interlocks. |
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Definition
| -Auto shut on an ECCS signal. |
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Term
CS
Describe the outboard injection valve (MO-1751/1752) interlocks. |
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Definition
-Outboard will get an auto open signal if shut and a pump auto start signal and pressure < or equal to 420# (can bypass by kelock on C-03).
-If > 420# the inboard valve must be shut prior to opening outboard (bypassed by auto open signal).
-For manual initiation outboard must be opened prior to inboard. |
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Term
CS
Describe the inboard injection valve (MO-1753/1754) interlocks. |
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Definition
-Auto open if pump start signal and < or equal to 420#.
-This signal is bypassed by taking handswitch to shut (can throttle).
-Outboard valve MUST be fully closed prior to opening inboard valve.
-Interlock bypassed on inboard valve ONLY when RPV pressure is < 420 psig. -Therefore outboard valve MUST be opened first for manual system operation. |
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Term
CS
Describe the inside drywell containment valve. |
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Definition
| 1 AO check valve per each core spray loop downsteam of the injection valves. |
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Term
CS
Describe the CS initiation logic. |
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Definition
-1.84# DW pressure.
-47” Low-low RPV water level AND low RPV pressure (<420 psig).
-47” Low-low RPV water level for 20 minutes.
-NOTE: All these start the pumps, pressure must be < or equal to 420# for injection valves to open. |
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Term
CS
Describe the relationship with the EDGs. |
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Definition
| -Diesel starting logic comes from CS to start EDG on high drywell pressure or low-low level. |
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Term
CS
Describe the relationship with SW/ESW. |
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Definition
-Provides cooling to core spray motor oil coolers and ECCS room cooling units.
-Loss of SW/ESW impacts core spray pump motor operability and will restrict pump run time.
-CS pumps must be declared INOP if cooling supply is lost to room coolers.
-Cooling water flow SHALL be maintained to motor bearing cooler; however, if cooling water is lost, pumps are still operable. |
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Term
CS
Describe the ECCS sump pump requirements. |
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Definition
-2 sump pumps per room, 4 total.
-1 total pump must be operable or both CS channels must be declared inoperable. |
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Term
CS
Describe the relationship with ASDS. |
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Definition
-Can run the 12 side of CS from ASDS.
-No interlocks when on ASDS. |
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Term
CS
Describe the relationship with ECCS room coolers. |
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Definition
-Provide cooling to RHR rooms.
-Must be started within 13 minutes of ECCS pump start.
-Service water provides cooling to area cooling units.
-ESW acts as backup on loss of normal service water. |
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Term
CS
Describe the major component power supplies. |
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Definition
-11 and 12 pumps from 15 & 16 busses.
-MOVs from 133B/143B.
-AO check valves: Y-20.
-CS logic: 15/16 bus.
-Breaker control power: D111/D211.
-Instrument channels: 125 Vdc Y70/Y80. |
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Term
CS
Describe the system keepfill supply and minimum pressure. |
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Definition
-Supplied from condensate water.
-Minimum pressure of 30psig to remain operable.
-Normally kept at 40psig. |
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Term
CS
Describe how long it takes for a pump to start on a CS initiation signal. |
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Definition
-15 seconds as part of the ECCS logic.
-5 seconds the first to RHR pumps start and 10 seconds the second 2 start. |
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Term
CS
Describe leak detection from the core back to CS. |
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Definition
-Pressure detector between injection valves and check valve downsteam of pump and min flow line.
-Alarms at 325#. |
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