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SI Setpoints - General
- PZR Pressure
- Steamline Pressure
- Containment Pressure
- Manual
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SI Setpoints - PZR Pressure
< 1829 psig
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SI Setpoints - Steamline Pressure
< 640 psig
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SI Setpoints - Containment Pressure
> 3.4 psig
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SI Setpoints - Manual
If it does not automatically actuate it can be manually triggered
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ECCS - Purpose
Maintain Rx coolant inventory in order to protect against grosss failure of the fuel cladding
Minimize core damage due to excessive temperature following a LOCA
Provide additional shutdown capability in the event of a Main Steam system break
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ECCS - Design Basis
Limit H2 production to < 1% of total possible from zircwater reaction
Maintain clad oxidation <17% of total clad thickness
Limit peak clad temperature <2200F
Maintain coolable core geometry
Long term core cooling
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ECCS - Unique Components
- Safety Injection pumps
- Pressurized accumulators
- Containment Recirculation Sumps
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ECCS - Shared Components
- Charging pumps
- RHR pumps
- RHR Heat exchangers
- RWST
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ECCS - Normal Aligned to
Auto inject on an SI signal
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RWST - Function
Supply borated water for ECCS operations or filling of the refueling cavity
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RWST - Construction
Concrete tank with a Stainless Steel liner
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RWST - Venting
Vented to filtered ventilation and vacuum breaker at 8" of water
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RWST - Heater Location
Located in RWST tunnel
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RWST - Location
Between containments, outside of fuel handling building
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Order of Pump Shutoff Head
- CV @ 2600 psig
- SI @ 1500 psig
- RH @ 200 psig
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CV Pumps - Purpose
Pump water from RWST to RCS at system pressure
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CV Pump - Description
10 stage centrifugal pump
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CV Pump - Shutoff Head
2600 Psid
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CV Pump - Flows
- 150 GPMs @ 2500 Psid
- 550 GPms @ 600 Psid
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CV Pump - Lubrication
- Motor Driven Gear Pump
- Cooled by SX
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CV Pump - Location
364' Aux. Building inside cubicle
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SI Pump - Purpose
Pump borated water from RWST to RCS when RCS pressure drops below pump shutoff head
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SI Pump - Description
10 Stage centrifugal
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SI Pump - Shutoff Head
1500 Psid
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SI Pump - Flows
- 400 GPMs @ 1200 Psid
- 650 GPMs @ 800 Psid
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SI Pump - Lubrication
- Shaft driven gear type pump
- Cooled by SX
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SI Pump - Location
364' Aux. inside cubicle
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SI Pump - Purpose of Discharge Relief Valve
Prevents overpressure due to check valve back-leakage
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SI Accumulators - Purpose
- Provide an immediate source of borated water to the reactor core in the event of a large RCS pipe rupture
- Provides initial surge of cooling water during large RCS pipe ruptures
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SI Accumulators - Capacity
10,100 gallons
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SI Accumulators - Cb
2200-2400 Ppm
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SI Accumulators - Level
- 31 to 63%
- 6995 to 7217 Gallons
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SI Accumulators - Pressure
602 to 647 Psi
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SI Accumulators - Connected To
- Cold leg of the RCS
- Isolated by 2 check valves
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SI Accumulators - Contents
- Pressurized with Nitrogen
- Partially filled with Borated Water
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SI Accumulators - Can Drained to
RWST or AB HUTs
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SI Accumulators - When is it isolated
When RCS pressure is less than 1000 psig
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SI Accumulators - Changing Cb
Can be bled and fed with the SI pumps to change Cb
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SI Accumulators - Location
426' Level on Containment
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RHR Pumps - Function
- Deliver reactor coolant flow through the RHR heat exchangers to meet plant cooldown requirements
- Supply borated water to the RCS, the suction of the Centrifugal CV pumps and the suction of the SI pumps during an ECCS actuation
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RHR Pumps - Description
Vertically Mounted centrifugal pumps
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RHR Pumps - Shutoff Head
200 Psid
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RHR Pumps - Flow
- 3000 GPMs @ 165 psid
- 5000 GPMs @ 125 psid
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RHR Pumps - Location
346' Aux. in cubicles
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RHR Heat Exchangers - Function
Transfer reactor decay heat to the Component Cooling Water System
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RHR Heat Exchangers - Description
Two vertically mounted shell and U-tube heat exchangers
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RHR Heat Exchangers - Tube Side
RCS
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RHR Heat Exchangers - Shellside
Component Cooling Water
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RHR Heat Exchangers - During ECCS
Borated water flows through tubeside
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RHR Heat Exchangers - Location
364' to 383' Aux. Building in cubicle
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CONTAINMENT Recir Sump - Purpose
Collect water from a RCS rupture for reuse by ECCS
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CONTAINMENT Recir Sump - Description
- Two sumps in each containment
- Covered by Screen to minimize blockage
- 114" Deep
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CONTAINMENT Recir Sump - Connected To
Suction of RHR pump and Containment Spray pump
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CONTAINMENT Recir Sump - Location
377' Inside Containment
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ECCS Interconnections - Systems
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ECCS Interconnections - RCS
- CV pumps discharge to the cold legs via a common header. This is the HIGH HEAD safety injection flowpath
- Accumulators, RHR pumps and SI pumps discharge to the RCS cold legs via common headers. This is the LOW HEAD safety injection flowpath.
- RHR pumps and SI pumps can also discharge to the RCS hot legs
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ECCS Interconnections - CVCS
- During the injection phase, the CV pumps take a suction on the RWST and discharge to the RCS cold legs
- During the recirculation phase, CV pump suction is shifted to take water from the outlet of the RHR Hx.Discharge is still to the RCS cold legs.
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ECCS Interconnections - AB
- All ECCS pressure relief valves (except the accumulators) relieve to the AB HUT’s
- Accumulators can drain to the AB HUT’s or the RWST.
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ECCS Interconnections - RHR
- During the injection phase, the RH pumps take a suction on the RWST and discharge to the RCS cold legs
- During recirculation phase, the RH pumps take a suction on their respective containment recirculation sump.
- 1A RH pump discharges to the CV pump suction
- 1B RH pump discharges to the SI pump suction, and both pumps discharge to the RCS.
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ECCS Support Sytems - List
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ECCS Support Sytems - IA
AOVs
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ECCS Support Sytems - CC
- Shaft seal cooler of the RHR pumps
- Removes heat from RHR Heat Exchangers
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ECCS Support Sytems - SX
- CV pump gear oil coolers
- CV and Si pump lube oild coolers and cubicle coolers
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ECCS Valves - Loss of DC or IA
AOVs will fail in a safe position
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ECCS Valves - SVAG stands for
Spurious Valve Actuation Guidelines
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ECCS SVAG - Description
Manually controlled, electrically operated valves where a single failure can result in performing an undesireable mechanical motion.
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ECCS SVAG - Avoiding
Disconnect power to these valves after they are manipulated to the correct position
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ECCS Operation - When are you in Standby
System aligned to auto inject at RCS temperatures > 350 degrees
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ECCS Operation - Standby
With the reactor in any other condition other than cold shutdown, the ECCS is aligned to automatically inject water from the SI accumulators and the RWST to the RCS cold legs
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ECCS Operation - Phases
- Injection
- Cold Leg Recirculation
- Hot Leg Recirculation
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ECCS Operation - High Head Injection
RWST | to | CV pumps | discharge to a common header | to all 4 RCS cold legs.
RWST | to | SI pumps | to all 4 RCS cold legs
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ECCS Operation - Low Head Injection
RWST | to | RHR | through | RHR Hx’s. (No CC water through the RHR Hx during injection phase) | mixes with | SI pumps | discharges to | All four COLD Legs
SI accumulators | mixes with | RHR and SI pump | discharges to | All four COLD Legs
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ECCS Operation - Cold Leg Recirculation Initiation
RWST Low-2 alarm
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ECCS Operation - Cold Leg Recirculation
CNTM Sump | to | RHR Pump | to | RHR Hx – CC removes heat | to | RCS cold legs, CV and SI Suction | Drains to | CNTM Sump
CV and SI Suction | to | RCS cold legs | Drains to | CNTM Sump
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ECCS Operation - Hot Leg Recirc
CNTM Sump | to | RHR Pump | to | _A RHR Hx – CC removes heat | to | _A and _C hot legs, and to the suction of the CV pumps
CV pumps still injecting into Cold Legs
CNTM Sump | to | RHR Pump | to | _B RHR Hx – CC removes heat | to | suction of the SI pumps
_A SI pump | to | _A and _D hot legs
_B SI pump | to | _B and _C hot legs
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ECCS Operation - Hot Leg Recirc Purpose
Increases Core flow (assuming Cold Leg break)
Prevent boron plating out (due to boiling) which would: Block flow Channels and Reduce heat transfer.
Initiated after Cold Leg Recirc at 5 hrs 50 mins after SI (with 20 min completion time)
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ECCS Operation - Steamline Rupture Purposes
Adds borated water to counteract (+) reactivity added by cooldown
Adds mass to RCS to counteract the volume reduction due to cooldown
Feedwater Isolation to minimize cooldown
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ECCS Operation - Steamline Rupture Cautions
RCS pressure may remain near NOP due to no RCS leakage
Continued operation of CV pumps will cause PZR PORV to lift
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ECCS Operation - Steamline Rupture Termination
SI will be manually terminated
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RWST Heater - Purpose
Circulates the contents of the RWST for samples and temperature control
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RWST Heater - Tempurature Concerns
- < 35 degrees operability due to freezing
- > 100 degrees ability to remove heat
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RWST Heater - CNTRL in AUTO
AUTO—the pump and heater cycle on and off based on temperature in the RWST. The pump and heater start at 58°F decreasing and stop at 65°F increasing.
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RWST Heater - CNTRL in OFF
Heater and Pump are not running
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RWST Heater - CNTRL in START
Pump runs but heater is off
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