SALEM
SALEM STUDY SYSTEM
Systems > RCPs

RCPs

⚠️ DRAFT

RCPs

Function

Each reactor coolant loop contains a vertical, single-stage, mixed-flow pump with a controlled leakage seal assembly. The pumps circulate reactor coolant through the core, piping, and steam generators. (UFSAR 5.1, 5.5.1)

Key Design Parameters

ParameterValueSource
Number of Pumps4UFSAR T5.2-6
Model93AUFSAR T5.2-6
Design/Operating Pressure2485 / 2235 psigUFSAR T5.2-6
Hydrostatic Test Pressure (cold)3107 psigUFSAR T5.2-6
Design Temperature (casing)650°FUFSAR T5.2-6
RPM at Nameplate Rating1180UFSAR T5.2-6
Suction Temperature559°FUFSAR T5.2-6
Developed Head277 ftUFSAR T5.2-6
Capacity88500 gpmUFSAR T5.2-6
Seal Water Injection8 gpmUFSAR T5.2-6
Seal Water Return3 gpmUFSAR T5.2-6
Pump Discharge Nozzle ID27½ inUFSAR T5.2-6
Pump Suction Nozzle ID31 inUFSAR T5.2-6
Overall Unit Height25 ft 5¼ inUFSAR T5.2-6
Water Volume56 ft³UFSAR T5.2-6
Pump-Motor Moment of Inertia82000 lb-ft²UFSAR T5.2-6
Pump Weight (dry)169200 lbUFSAR T5.2-6

Motor Data

ParameterValueSource
TypeAC Induction, Single Speed, Air CooledUFSAR T5.2-6
Voltage4160 VUFSAR T5.2-6
Phase3UFSAR T5.2-6
Frequency60 HzUFSAR T5.2-6
Power (nameplate)6000 HPUFSAR T5.2-6
Starting Current4800 ampsUFSAR T5.2-6
Input (hot reactor coolant)4260 kWUFSAR T5.2-6
Input (cold reactor coolant)5690 kWUFSAR T5.2-6
InsulationClass B Thermalastic EpoxyUFSAR T5.2-6

Design Features

  • Flow path: Coolant drawn up through impeller, discharged through diffuser passages and out discharge nozzle
  • Maintenance: Rotor-impeller can be removed without removing casing from piping
  • Materials: All parts in contact with reactor coolant are austenitic stainless steel or equivalent corrosion-resistant materials
  • Controlled leakage seal assembly: Three-stage seal with seal water injection from CVCS (8 gpm in, 3 gpm return)
  • Flywheel: Provides coastdown flow during loss of power (moment of inertia 82000 lb-ft²)
  • Anti-reverse rotation device: Prevents reverse rotation on loss of power
  • (UFSAR 5.1, 5.5.1)

RCP Seal System

Exam — 2022 Q28
RCP #2 seal is a face rubbing seal with a design leak-off of 3 gph to the RCP standpipe. Upon #1 seal failure, #2 seal converts from face rubbing to film riding seal — acts as emergency backup only. Not designed for sustained high flow/high temperature operation; RCP must be shut down if #1 seal fails. 100 cc/hr is #3 seal design leakage, not #2 seal. #1 seal is the film riding seal — do not confuse #1 and #2 seal types.
Exam — 2023 Q10
If ANY RCP seal inlet temperature is ≥ 225°F, restoring seal injection flow is NOT permitted. Seal injection must be isolated before starting the charging pump. This prevents thermal shock and damage to the #1 seal from cold seal injection water contacting hot seal components.
Exam — 2023 Q4
RCP thermal barrier rupture indications: (1) CCW radiation monitors (R17 A/B) in warning — RCS leaking into CCW, (2) CCW surge tank level rising, (3) CC131 thermal barrier isolation valve goes CLOSED on high CCW flow. PZR level does NOT rise (RCS is leaking OUT). Charging flow does NOT lower.
Exam — 2020 Q4
AB.RCP-0001 Attachment 2 CAS trip criteria — distinguishing near-miss values from actual limits:
- Motor winding temp >302°F → trip RCP (320°F exceeds this)
- Motor bearing temp >175°F → trip RCP (170°F does NOT exceed this — common distractor)
- Motor flange vibration >5 mils → trip RCP (3 mils is an AB.RCP-0001 entry condition, NOT a CAS trip criterion)
- CC-131 closure (thermal barrier valve) alone for >2 min does NOT require tripping the RCP — CAS requires concurrent loss of seal injection AND thermal barrier CCW to secure RCPs within 2 minutes.
Exam — 2023 Q27
Per AB.RCP-0001: loss of CCW to motor bearings — 5 minutes to restore CCW or trip reactor and stop RCP. Motor bearing temp limit: 175°F. Additional trip criteria: motor winding temp >302°F, seal outlet >190°F, shaft vibration >20 mils, #1 seal leakoff <0.8 or ≥6 gpm. 165°F is the ARP limit that directs entry into AB.RCP-0001, NOT the trip limit (175°F).

Seal Failure Diagnostics Summary

IndicationSeal Problem
Standpipe Level HI + #1 seal leak-off LOW#2 seal failure
Standpipe Level LO#3 seal problem
#1 seal leak-off >= 6 gpm#1 seal failure
Exam — 2020 Q28
RCP STANDPIPE LEVEL HI alarm with #1 seal leak-off flow lowered = #2 seal failure indication. Both standpipe level high AND reduced #1 seal leak-off flow confirm #2 seal failure. Standpipe level LOW is a #3 seal indication — do not confuse high vs low standpipe alarms. High standpipe = #2 seal; Low standpipe = #3 seal.
  • Seal inlet temp limit: ≥225°F — do not restore seal injection (prevents #1 seal thermal shock damage)
  • Seal outlet temp limit: 190°F — monitored to prevent Safe Shutdown Seal actuation
  • CC131 Thermal Barrier Valve: Closes automatically on high CCW flow to thermal barrier (indicates thermal barrier leak)
Exam — 2023 Q26
EOP-TRIP-4 RCP restart priority for PZR spray: 23 RCP preferred (single pump for normal spray). If 23 unavailable: 21+22 or 21+24 (two pumps needed for spray via auxiliary spray line). Forced convection permits faster cooldown with less potential for upper head voiding. Single pump operation preferred over two.
Exam — 2023 Q78
RCP vibration abnormal response: with shaft vibration at 16 mils (below 20 mil trip limit) and motor flange vibration at 3 mils (below 5 mil trip limit), the Attachment 1 trip criteria of AB.RCP-0001 are NOT exceeded. Per Step 3.10, the CRS/SM determines if a controlled Unit shutdown is required — immediate RCP trip and reactor trip are not warranted. OHA D-36 directs entry into AB.RCP-0001 but does NOT direct tripping the reactor or stopping the RCP.

RCP Starting Requirements

Exam — 2019 Q1
Per S2.OP-SO.RC-0001 Limitations, with one or more RCS Cold Leg temperatures ≤312°F, at least one of the following conditions shall be met before starting an RCP: (1) PZR level <92%, OR (2) all SG secondary temps <50°F above any RCS Cold Leg temp. Starting an RCP when criteria are NOT met results in an RCS pressure transient from secondary energy addition. Only ONE condition needs to be met, not both. The concern is RCS pressure transient, not RCP motor degradation.

Loss of Offsite Power

On loss of offsite AC power, reactor coolant pumps are tripped. The flywheel moment of inertia (82000 lb-ft²) provides coastdown flow sufficient to prevent fuel damage. (UFSAR 5.5.1.3.13)

Exam — 2023 Q1
Low RC flow trip requires 2/3 channels ≤90% of design loop flow per loop. Between P-7 (10%) and P-8 (36%), loss of flow on a single loop does NOT cause an automatic trip — Tech Specs do not allow 3-loop operation in Mode 1, so per S2.OP-AR.ZZ-0004, the operator must manually trip the reactor and stop the affected RCP.
Exam — 2018 Q1
13 RCP shaft shear at 25% power: since 25% is below P-8 (36%), the low flow reactor trip setpoint is met for only the 13 loop, and the reactor will NOT trip. Normal full PZR spray capability is NOT available — PZR spray is produced from the 11 and 13 loop D/Ps (13 and 11 RCPs), and 13 RCP produces most of the spray flow. Trap: above P-7 (10%) but below P-8 (36%), the single-loop low flow trip is blocked. Candidates may confuse the P-7 and P-8 permissives.

Loss of Component Cooling Water

Loss of CCW to the RCPs requires pump trip to protect the seals and thermal barrier. (UFSAR 5.5.1.3.14)

Exam — 2020 Q78
Per AB.CC-0001, three time-critical RCP protection criteria on loss of CCW:
1. Motor bearing temp reaches 175°F → stop RCPs (calculate from initial temp + rate of rise)
2. CCW Surge Tank Level cannot be maintained > 38% → immediately stop RCPs
3. 5 minutes after "RCP BRG CLG WTR FLO LO" alarms (OHAs D-20 through D-23) → stop RCPs
The 175°F motor bearing limit is often the EARLIEST action when temp is rising fast. In the exam scenario: 140°F rising at 5°F/min = 175°F at T+7 min (earlier than the 5-min flow alarm timer at T+10 min). Also, the old 2-minute criterion applied only when BOTH seal injection AND thermal barrier flow were lost concurrently — does not apply when seal injection is still available.
Exam — 2023 Q86
RCP #3 seal leak identification: STANDPIPE LEVEL-LO alarm is the primary indicator of a #3 seal leak. Key diagnostic: #1 seal leakoff flow steady at 1.5 gpm (normal — indicating intact #2 seal) while standpipe level is low. Action: make-up to the standpipe per ARP; power operation may continue. AB.RCP-0001 does not direct actions for a #3 seal leak specifically. Trap: orderly shutdown and stop RCP within 8 hours is the action for a degraded #2 seal, not a #3 seal leak.

Seal Injection Flow Surveillance

Exam -- 2023 Q91
TS 3.5.4 limits total RCP seal injection flow to ≤40 gpm (with charging header pressure ≥2430 psig and 2CV55 fully open). Individual RCP seal injection flows totaling 40.5 gpm (e.g., 10 + 10.5 + 9.8 + 10.2) exceed the limit. Required action: adjust manual seal injection throttle valves within 4 hours. Trap: this is NOT a charging pump operability issue (TS 3.5.2) -- it is a seal injection flow limit issue (TS 3.5.4). The TS 4.0.4 exemption allows up to 4 hours for adjustment, but this is NOT the same as "no TS action required."
Exam — 2022 Q76
EOP-FRSM-1 (ATWS) RCP trip restriction: per Caution C1-1, RCPs should NOT be tripped when reactor power is >5%. During an ATWS, RCP operation provides temporary core cooling under voided RCS conditions. Even if RCP trip criteria are met (e.g. motor flange vibration >5 mils), the RCP should NOT be stopped while power exceeds 5%. Tripping an RCP during ATWS with power >5% could reduce heat removal and challenge fuel integrity — the ATWS caution takes precedence over normal RCP trip criteria.
Exam — 2022 Q86
RCP #1 seal failure identification: seal leak-off flow >=6 gpm indicates #1 seal failure. Per AB.RCP-0001 Attachment 1: if #1 seal leak-off >=6 gpm, go to Attachment 2 (Stopping RCPs) → manual reactor trip, stop the affected RCP, then 3-5 minutes later close the associated CV104. Orderly shutdown and stop RCP within 8 hours is the action for a degraded #2 seal (leak-off <0.8 gpm or slowly approaching 6 gpm at step 3.6) — NOT for a failed #1 seal.

Tech Spec LCOs

  • TS 3/4.4 — Reactor Coolant System|TS 3/4.4.1 — Reactor Coolant Loops (minimum loops in operation by mode)
JPM — 2022 Sim-d
RCP standpipe low level alarm response (S2.OP-AR.ZZ-0011 Page 138): caused by low seal flow across #2 seal or excessive #3 seal flow. Key check: if standpipe low AND seal leakoff flow alarm together → go to AB.RCP-0001. If standpipe low ONLY → fill: open 2WR80 (PW to CONTMT STOP V) on 2CC2, then 21WR62 (Standpipe Supply Valve) on 21 RCP bezel. When hi level alarm, close all and stop PW pump.
Scenario — 2022 #3
23 RCP motor bearing oil level OHA actuates. Motor bearing temperatures and vibrations rising — exceed AB.RCP-0001 trip criteria of motor bearing temp > 175 degF or motor vibrations > 5 mils. CRS directs RO to trip reactor and stop 23 RCP IAW AB.RCP-0001 Attachment 2. Event triggers entry to EOP-TRIP-1.
Scenario — 2020 #4
23 RCP shaft vibration exceeds 20 mils on 2RP3 monitor (OHA D-36 RCP VIB HI). CRS enters AB.RCP-0001 and implements CAS — trip reactor and stop 23 RCP. Consequence: loss of 23 RCP means normal PZR spray unavailable during subsequent SGTR-1 depressurization (spray valves fed from loops 1 and 3 cold legs). RCS depressurization must use PZR PORVs instead. Also: 23 SG NR level may appear to rise after 23 RCP stop due to loss of forced circulation reducing steaming effect.
Scenario — 2018 #1
22 RCP #1 seal degradation: seal leakoff flow rises and stabilizes at ~5.2 gpm. CRS enters AB.RCP-0001, checks P-250 computer for RCP conditions. CCW normal, winding temps normal, seal injection >6 gpm. CRS determines orderly shutdown required with 8-hour limit to stop 22 RCP. Seal then fails — leakoff exceeds 6 gpm, triggering Att 1 CAS and Att 2 (Stopping RCPs). CT#1: Trip reactor, stop 22 RCP, close 22CV104 within 3-5 minutes. The 3-minute delay allows RCP coastdown for #2 seal backup function; the 5-minute limit minimizes RCS inventory loss from the damaged seal.
Exam — 2019 Q53
RCP shaft shear at 25% power — thermodynamic effects on the affected loop: with 13 RCP shaft sheared, Loop 13 RCS flow goes to minimum and 13 SG steam flow lowers significantly. This causes: (1) 13 RCS Loop ΔT LOWERS (reduced heat transfer due to minimal flow), and (2) 13 SG NR Level initially SHRINKS (reduced steam flow → reduced voiding in SG → apparent level drop). Trap: candidates may confuse the ΔT response — with minimal loop flow, less heat is being removed from the core through that loop, so the loop ΔT decreases. Also: shrink occurs from the rapid decrease in steam production, not from swell.

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