SALEM
SALEM STUDY SYSTEM
Systems > CCW

CCW

⚠️ DRAFT

CCW

Function

Closed-loop cooling water system that provides an intermediate barrier between potentially radioactive systems and the service water system. Removes heat from various plant components and transfers it to the service water system. (UFSAR 9.2.2)

Key Loads

  • Reactor coolant pump thermal barriers and motor coolers
  • Residual heat removal heat exchangers (shutdown cooling)
  • Letdown heat exchanger (CVCS)
  • Excess letdown heat exchanger
  • Spent fuel pool heat exchangers
  • Sample coolers
  • Reactor support and nozzle cooling

Key Components

  • Component cooling heat exchangers: Cooled by service water
  • Component cooling pumps: Circulate CCW through the closed loop
  • Component cooling surge tank: Maintains system filled, accommodates thermal expansion

Key Design Points

  • Closed loop prevents direct contact between potentially radioactive fluids and service water
  • Surge tank provides indication of system leakage (radioactivity monitoring on CCW)
  • Loss of CCW to RCPs requires RCP trip to protect seals and thermal barrier (UFSAR 5.5.1.3.14)
Exam — 2020 Q55
CCW containment isolation signals: CC131 and CC190 (RCP Thermal Barrier CCW Isolation Valves) receive a Phase B signal to close, NOT Phase A. CC113 and CC215 (Excess Letdown CCW Valves) receive a Phase A signal to close. The thermal barrier CCW isolation (CC131/CC190) is Phase B, while excess letdown CCW isolation (CC113/CC215) is Phase A — do not confuse the isolation signal levels for these two different CCW flow paths through containment.
Exam — 2022 Q5
1CC190 (CCW Thermal Barrier Isolation Valve) is on the COMMON CCW return line — closing it isolates thermal barrier return from ALL RCPs (not just one). Individual RCP isolation valves are the CC130s (one per RCP). RCPs may continue operating as long as charging flow is maintained for seal injection.
Exam — 2022 Q8
Per AB.CC-0001 Attachment 1, RCP motor bearing temperature limit requiring reactor trip and stopping the affected RCP is 175°F.
Exam — 2022 Q35
Per AB.CC-0001 Attachment 1: CCW surge tank level low at 5% requires reactor trip AND tripping all RCPs. Per Attachment 2: also isolate letdown and swap charging pump suction to RWST, then go to EOP-TRIP-1. 17% is the low VCT level action — not the CCW surge tank trip limit. CCW surge tank trip level is 5%.
Exam — 2022 Q36
Two sources of RCS inleakage to CCW: (1) Seal Water HX and (2) RCP Thermal Barrier HX. These are the only two CCW-cooled components where RCS pressure exceeds CCW pressure, allowing primary-to-CCW leakage. CCW HX leak = Service Water into CCW (not RCS). SFP HX leak = CCW out-leakage into SFP (CCW pressure > SFP). Regen HX is NOT cooled by CCW.
Exam — 2023 Q4
RCP Thermal Barrier rupture indications: CCW surge tank level rises (RCS leaks OUT to CCW), R17A/B CCW radiation monitors rise (detecting RCS activity in CCW), and CC131 (RCP Thermal Barrier Valve) closes on high CCW flow to the thermal barrier. PZR level does NOT rise — RCS is leaking out, not in. Charging flow does NOT lower.
Exam — 2020 Q34
Thermal barrier HX leak diagnostic: the "Discharge Flow Lo" alarm on 2CC1 is the unique indicator of automatic 2CC131 (RCP Thermal Barrier Valve) closure. CC HDR ACTIVITY HI + SURGE TANK LEVEL HI-LO + DISCHARGE FLOW LO = thermal barrier HX leak. The Discharge Flow Hi alarm fires first (high CCW flow from RCS in-leakage) triggering auto-closure of 2CC131, then DISCHARGE FLOW LO follows. Letdown HX and RHR HX are also high-pressure CCW in-leakage sources, but they would NOT cause the "Discharge Flow Lo" alarm. RHR HX is not in service at 100% power. Seal Water HX is NOT a high-pressure source — #1 seal leakoff pressure is below CCW pressure.
Exam — 2023 Q33
SEC Mode 3 (SI + LOOP): all CCW pumps are tripped — CCW pumps are NOT sequenced onto EDGs due to loading concerns. SW to CCW HXs is auto-isolated to prevent SW pump runout with only 3 SW pumps available on emergency power. CCW pumps are started later per EOP-APPX-1 when needed for cold leg recirculation.
Exam — 2023 Q51
SW122 (SW Inlet Control Valve to CCW HX) fails OPEN on loss of air (fails closed on loss of 125VDC). When SW122 fails open: increased SW flow through CCW HX → CCW temperature lowers → RHR HX outlet temperature lowers → RCS cooldown rate rises. Per AB.CA-0001, SW122 can be manually operated.
Exam — 2020 Q35
SEC Mode III (Blackout + SI): CCW pumps are stripped and NOT reloaded. Additionally, a pump selected for AUTO is transferred to Manual during Modes II, III, and VI. After successful SEC loading: all CCW pumps stopped, all in Manual. Trap: Mode II (Blackout only) DOES restart CCW pumps. Mode I (SI only) retains AUTO selection. Only Modes II, III, and VI force AUTO to Manual.
Exam — 2020 Q76
Following MODE III (LBLOCA + LOOP), CCW restoration per EOP-APPX-1: the CCW pump to start is chosen based on which EDG has adequate margin from out-of-service equipment. With 21 AFW Pump out of service, 2A EDG has margin → start 21 CCW Pump. With 22 CFCU out of service, 2B EDG does NOT have adequate margin for 22 CCW Pump. Both CCW HXs are placed in service because at least three SW pumps are running.
Exam — 2020 Q78
Per AB.CC-0001 Attachment 1, three time-critical actions for RCP protection on loss of CCW:
1. Motor bearing temperature reaches 175°F → stop RCPs
2. CCW Surge Tank Level cannot be maintained > 38% → immediately stop RCPs
3. 5 minutes after "RCP BRG CLG WTR FLO LO" alarm (OHAs D-20 through D-23) → stop RCPs
Trap: 2 minutes was previously the time to stop RCPs if BOTH seal injection and thermal barrier flow were lost concurrently — does not apply if only CCW is lost (seal injection still available from charging).
Exam — 2019 Q5
SEC Mode III (SI + LOOP): CCW pumps are NOT automatically reloaded by the SECs. After SEC Mode III loading completes, CCW pumps remain stopped. CCW cools ECCS components (RHR Pumps, RHR HX, SI Pumps), but this is not sufficient to cause the SECs to auto-start CCW due to EDG loading limitations.
Exam — 2019 Q55
CC131 (RCP Thermal Barrier Valve) auto-closure setpoints: CC131 automatically CLOSES when CCW flow from the RCP Thermal Barrier reaches 175 gpm. The lo flow alarm setpoint of CC131 is 145 gpm (fires after CC131 closes and flow drops below 145 gpm). Per AB.RCP-0001 CAS: with only thermal barrier CCW flow lost and RCP injection flow normal, the crew is NOT required to secure ALL RCPs within 2 minutes. Trap: 145 gpm is the CC131 lo flow alarm setpoint, NOT the auto-closure setpoint. Auto-closure is at 175 gpm (hi flow). The 2-minute RCP trip criterion requires BOTH seal injection AND thermal barrier CCW lost concurrently.
Exam — 2018 Q7
2CC149 (CCW Surge Tank Vent Valve) automatically CLOSES on high radiation alarm from 2R17A/B (Component Cooling Process Monitors). 2CC149 is normally OPEN. Per AB.CC-0001 Step 3.8 NOTE: allowing CCW Surge Tank to overflow will contaminate the in-service Waste Holdup Tank AND the 22 ABV Exhaust Filter Unit. Trap: the 22 ABV Exhaust Filter Unit contamination is easily missed — the overflow affects two components, not just the Waste Holdup Tank.
Exam — 2019 Q8
Confirms 2018 Q7: 2CC149 auto-closes on 2R17A/B high radiation alarm. CCW Surge Tank overflow contaminates both the in-service Waste Holdup Tank and the 22 ABV Exhaust Filter Unit.

Tech Spec LCOs

  • TS 3/4.7 — Plant Systems — TS 3.7.3 requires two independent CCW loops OPERABLE in Modes 1–4
  • 1 loop inoperable: 72 hours to restore, or Hot Standby in 6 hours + Cold Shutdown in 30 hours
Exam — 2023 Q59
SFP Heat Exchanger tube rupture: components supplied by CCW with pressure less than CCW header pressure are sources for system-to-system out leakage. A tube rupture in the SFP HX results in CCW leaking OUT into the SFP system — CCW Surge Tank level lowers, SFP level rises. Non-borated CCW reduces SFP boron concentration, requiring addition of borated water. SFP alarms: low level 128' 2", high level 129' 2".
JPM — 2019 Sim-h
CCW leak inside containment per S2.OP-AB.CC-0001 (alternate path JPM): initial CCW leak causes OHA C-2 CNTMT SUMP PMP START and CCW Surge Tank Level Hi-Lo console alarm. Operator initiates makeup via 2DR107. After isolating Excess Letdown HX valves (2CV132, 2CC215, 2CC113), leak worsens beyond makeup capacity — Attachment 2 directs reactor trip, stop ALL RCPs, and close CCW containment isolation valves (2CC131, 2CC136, 2CC190). Step 3.24 is the decision point: Surge Tank level cannot be maintained >5% with makeup in progress.
Exam — 2018 Q54
CCW leak location via chemistry: per AB.CC-0001, any inleakage dilutes CCW chromates. The discriminator for Service Water inleakage is rising chloride concentration. Rising chlorides + lowering chromates + rising surge tank level = CC Heat Exchanger leak (the interface between CCW and SW). Other CCW inleakage sources (Seal Water HX, Letdown HX, Charging Pump) also dilute chromates but do NOT increase chlorides because they do not interface with SW.
JPM — 2018 Sim-h
Start a CCW pump IAW EOP-APPX-1 during large break LOCA with loss of offsite power. 2B 4KV Vital Bus de-energized (Bus Differential, Diesel running). No CCW pumps running (SEC Mode 3). Step 3 strategy selection: de-energized bus = B → CCW pumps available = 21 or 23 → Strategy C → GO TO Step 6. 21 CCW pump fails to start (override): take RNO, reset CS, restart 21 CS pump, proceed to Step 6h. Successfully start 23 CCW pump on 2C bus. Requires SEC Block, Emergency Loading Reset, stopping CS pump to make room on SEC-loaded bus, then restarting CS after CCW starts.

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