SALEM
SALEM STUDY SYSTEM
Systems > Containment Spray

Containment Spray

⚠️ DRAFT

Containment Spray

Function

Reduces containment pressure and removes iodine from the containment atmosphere by spraying chemically treated (NaOH) water following a LOCA or other DBA. (UFSAR 6.2.2.1)

Actuation

  • Actuated on Hi-Hi Containment Pressure (“P” signal, 2/4 at 15.0 psig)
  • Phase B containment isolation also actuates on the “P” signal
  • Containment Spray bistables are energized to actuate (opposite of most ESF bistables) (UFSAR T7.2-1, TS Table 3.3-4)
Exam — 2020 Q88
CS Hi-Hi Containment Pressure bistables are energized to actuate. Loss of a VIB leaves the associated bistable de-energized (cannot contribute to actuation) → logic goes from 2/4 to 2/3. Per TS 3.3.2.1, the inoperable channel is placed in BYPASS (not tripped) to prevent spurious CS actuation. Most ESF bistables are de-energized to trip → inoperable channels are placed in TRIPPED. Containment Spray is the opposite.
Exam — 2019 Q14
Resetting one train of Containment Spray (after AUTOMATIC actuation without a manual backup): depress bezel button B ONLY. Key switches A and C are NOT required for reset when only an automatic actuation has occurred. Key switches A and C would be involved if a manual backup had been performed. Candidates confuse automatic-only reset (bezel button B) with reset following manual actuation.
Exam — 2019 Q15
EOP-LOCA-5 Table C CS pump determination with 2B 4KV bus de-energized: with Containment Pressure = 19 psig, RWST Level = 10 feet, and only 3 CFCUs running in slow speed (2B bus loss = 22 and 24 CFCUs unavailable), Table C shows 0 CS pumps required. Crew stops BOTH CS pumps. Must correctly count available CFCUs to enter Table C — the number of CFCUs running directly determines whether 0, 1, or 2 CS pumps are required.

Operation

Injection Phase

  • Spray pumps take suction from RWST
  • NaOH from spray additive tank mixed with spray flow via eductors
  • Spray into containment atmosphere

Recirculation Phase

  • Spray pumps realigned to containment sump via RHR heat exchangers
  • Cooled recirculated water sprayed into containment

Spray Nozzles

  • Hollow-cone pressure nozzle design, no internal parts subject to clogging
  • 3/8-inch diameter orifice, stainless steel
  • Sauter mean drop size < 1000 microns at design conditions
  • Four 360-degree ring headers at two elevations
  • Screened through 1/12-inch (2.1 mm) holes during recirculation (UFSAR 6.2.2.1)

Spray Additive System

ParameterValueSource
Spray Additive Tank Volume2568–4000 gallonsTS 3.6.2.2
NaOH Concentration30–32% by weightTS 3.6.2.2
Eductor Flow35 ±3.5 gpm to each spray systemTS SR 4.6.2.2
Spray Pump Differential Pressure≥204 psidTS SR 4.6.2.1

Key Design Points

  • Two independent containment spray systems
  • NaOH additive maintains post-LOCA sump pH between 7.0 and 10.0
  • pH control minimizes iodine re-evolution and chloride stress corrosion cracking
Exam — 2023 Q40
CS pump power supplies: 21 CS pump on A 4KV Vital Bus, 22 CS pump on C 4KV Vital Bus. A failed 2B SEC does NOT affect either CS pump. With SECs NOT reset after initial SI sequence, the CS pump start contact remains re-closed — CS pumps WILL auto-start on Hi-Hi containment pressure signal even after the initial SI sequence completes.
Exam — 2022 Q42
21 CS Pump powered from 2A 4KV Vital Bus, 22 CS Pump from 2C 4KV Vital Bus. With 2C bus de-energized, only 21 CS Pump is available. To manually start: must block and reset the associated SEC first, then use the keyswitch to start the CS pump. The start pushbutton alone will NOT start the CS pump when SECs have actuated — SEC sequences override manual pushbutton control. Must block/reset SEC and use keyswitch.

Tech Spec LCOs

  • TS 3/4.6 — Containment — TS 3.6.2.1 (Spray System), TS 3.6.2.2 (Spray Additive)
  • 1 spray system inoperable: 72 hours, then 48 more hours, or Cold Shutdown
Exam — 2023 Q77
EOP-LOCA-1 Step 7.4 (stop CS pumps when containment pressure below 13 psig) is a continuous action step. Per OP-SA-108-101-2002: continuous action steps are NOT performed during a Red or Purple path FRP. Even if conditions to stop CS pumps are met, the crew must transition to the FRP and not perform Step 7.4.
Exam — 2022 Q80
EOP-LOCA-5 vs EOP-FRCE-1 containment spray operation: per EOP-FRCE Caution C3-1, if LOCA-5 is in effect, operation of containment spray pumps should be IAW LOCA-5 (not FRCE-1). LOCA-5 has less restrictive criteria allowing reduction of CS pump operation based on RWST level and CFCUs to conserve RWST inventory. FRCE-1 establishes maximum available heat removal (more aggressive CS operation) which conflicts with LOCA-5 priority to conserve RWST inventory.
JPM — 2022 Sim-f
EOP-TRIP-1 Step 9 — manual CS/Phase B actuation during LBLOCA: containment pressure NOT < 15 psig → manually initiate Phase B and Spray using safeguards key switches on 2CC1. Alternate path: Phase B valves (2CC131, 2CC190) fail to auto-close and NaOH valves (2CS16, 2CS17) fail to auto-open on CS signal. Operator must verify Table B valve groups and manually reposition: close at least one 2CC131/2CC190 and open at least one 2CS16/2CS17.
Exam — 2020 Q42
EOP-LOCA-5 Table C determines required CS pumps: with RWST > 15.24 ft, containment pressure 18 psig, and 4 CFCUs operating → 0 CS pumps required. Correct CFCU count depends on knowing CFCU power supplies — losing the 2A Vital Bus does NOT affect CFCU count (CFCUs are powered from 460V buses, not 4KV vital buses directly). Candidates must know CFCU vs CS pump power supply mapping.
Exam — 2020 Q9
Confirms CS pump power supplies during MSLB + LOOP with 2C 4KV Vital Bus lost: 21 CS Pump (A bus) is available, 22 CS Pump (C bus) is NOT available. Containment cooling design bases: 3 CFCUs + 1 CS pump. With C bus lost, only 21 CS Pump available.
Exam — 2019 Q88
During cold leg recirculation, Containment Spray pumps take suction from the outlet of the RHR HXs. Therefore, the RHR pumps (not SI pumps) provide the D/P to drive Containment Spray during recirculation mode. SI pumps are plausible but incorrect — CS alignment in recirculation is via the RHR system.
JPM — 2020 Sim-e
EOP-TRIP-1 Step 11: manual CS/Phase B actuation during LBLOCA with containment pressure NOT < 15 psig. Use safeguards key switches on 2CC1. Alternate path: auto CS and Phase B signals fail. Phase B valves 2CC131 and 2CC190 (CCW containment isolation) remain open and NaOH discharge valves 2CS16 and 2CS17 remain closed. Step 11.4 Table D check reveals valves not in safeguards positions — operator manually repositions (close 2CC131/2CC190, open 2CS16/2CS17). NaOH valves provide sodium hydroxide to containment spray for iodine scrubbing and pH control.
Exam — 2018 Q13
NaOH (Sodium Hydroxide) is added to Containment Spray flow to remove elemental iodine from the containment atmosphere AND to prevent corrosion of containment components. Trap: Hydrazine is added to the RCS to scavenge oxygen — it is NOT added to Containment Spray flow. NaOH serves a dual purpose (iodine removal AND corrosion prevention), not just iodine removal alone.
Exam — 2018 Q14
Confirms CS pump power supplies and spray actuation setpoint during LOCA + LOOP with 2C 4KV Vital Bus faulted: Containment Spray actuation at 15 psig. With 2C bus de-energized, ONLY 21 CS Pump (2A bus) is running. 22 CS Pump (2C bus) is not available. Same power supply mapping tested on 2020 Q9, 2022 Q42, and 2023 Q40.
Exam — 2018 Q88
TS 3.6.2.1 application with BOTH trains of Containment Spray INOPERABLE: LCO 3.6.2.1 has NO action for both trains inoperable → LCO 3.0.3 applies. When ONE train is restored, LCO 3.0.3 exits and the single-inoperable-train action of LCO 3.6.2.1 begins: restore within 72 hours or be in HOT STANDBY within the next 6 hours. Key timing: the 72-hour clock starts from when the LCO was first NOT met (08:00 on June 12th), not from when one train was restored (10:00). Total: 72 + 6 = 78 hours from 08:00 on June 12th = 14:00 on June 15th.
JPM — 2018 SRO-A5
Emergency classification with degraded containment cooling: Containment pressure 35 psi, 21 CS pump failed to start (only 22 CS pump running). Combined with < 3 CFCUs in low speed → meets CB8.P (containment barrier potential loss, 2 pts) for fission product barrier assessment. This is a POTENTIAL loss, not a LOSS — containment barrier is degraded but not breached. Combined with RB2.L (5 pts) = 7 points total = SAE.
Scenario — 2018 #2
Both CS pumps start on Phase B actuation (containment pressure >15 psig) during LBLOCA. During EOP-LOCA-3 cold leg recirculation transfer, stop 22 CS pump within ~5.5 minutes of RWST lo level alarm (CT#2 Part 2). Only one CS pump remains running during recirculation alignment.

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