SALEM
SALEM STUDY SYSTEM
EOPs > EOP-SGTR-1 — Steam Generator Tube Rupture

EOP-SGTR-1 — Steam Generator Tube Rupture

⚠️ DRAFT

EOP-SGTR-1 — Steam Generator Tube Rupture

Purpose

Provides guidance for mitigation of a steam generator tube rupture event, including identification of the ruptured SG, isolation, cooldown, and depressurization to terminate primary-to-secondary leakage.

Key Actions / Information

Exam — 2022 Q11
Step 38.1 monitors for natural circulation flow. RCS T-Cold in unaffected loops should be approximately 548 °F (saturation temperature at MS10 setpoint of 1015 psig / 1030 psia). Affected SG MS10 set to 1045 psig (1060 psia) per step 3. With a LOOP, steam dumps are unavailable (circulators tripped = blocking signal) — use atmospheric relief valves (MS10s) on intact SGs to raise steam flow.
Exam — 2022 Q25
EOP-TRIP-7 Rediagnosis transitions to EOP-SGTR-1 when symptoms include rising SG level and SG high radiation (2R19A in alarm) — distinguishing a tube rupture from a LOCA or faulted SG.
Scenario — 2022 #4
Entered from EOP-TRIP-1 when 23 SG NR level rising in an uncontrolled manner following a 650 gpm tube rupture. Key actions in SGTR-1: identify 23 SG as ruptured, set 23MS10 to 1045 psig, isolate ruptured SG (close 23AF21, 23AF11, 23MS167, 23MS18, 23MS7, 23GB4, dispatch operator to close 23MS45, close 2SS333). Determine RCS target temperature using Table B: SG pressure > 1000 psig = 503 F CETs. Cooldown using steam dumps on intact SGs at maximum rate — bypass Tavg Lo-Lo pushbuttons. After reaching target temp, stop cooldown by placing MS Pressure Control in Auto. Reset SI, Phase A, Phase B. Depressurize using PZR spray valves per Table D criteria. When 2PS3 fails to close, stop 21 and 23 RCPs to eliminate spray flow path, continue at step 19.
Exam — 2020 Q79
EOP-SGTR-1 CAS (Continuous Action Step): If SI has been terminated and RCS subcooling reaches 0°F → start ECCS pumps as necessary to restore subcooling and GO TO EOP-SGTR-3 (SGTR with LOCA – Subcooled Recovery). This CAS monitors throughout the procedure. SGTR-3 (Subcooled Recovery) is the correct transition — NOT SGTR-4 (Saturated Recovery). SGTR-2 (Post SGTR Cooldown) is only for normal recovery when subcooling is maintained. The key discriminator is: SI has been TERMINATED + subcooling lost = SGTR-3.
Scenario — 2020 #4
Entered from EOP-TRIP-1 when 21 SG NR level rising in an uncontrolled manner following 650 gpm tube rupture. Isolate 21 SG: close 21AF21 and 21AF11 (feed — CT-18 Part 1, within 10 min), close 21MS167 (steam — CT-18 Part 2), set 21MS10 to 1045 psig. Dispatch to close 21MS45 and 2SS321. Trip 23 AFW pump (lower to min speed first). Target cooldown temp from Table B: SG press >1000 psig = 503 F CETs. Cooldown using steam dumps on intact SGs — bypass Tavg Lo-Lo pushbuttons. Stop cooldown placing MS Pressure Control in Auto (CT-19 Part 2). Normal spray NOT available (23 RCP stopped) — depressurize using PZR PORVs IAW Table E. PORV fails to close → close block valve (CT-10).
JPM — 2020 Sim-g
EOP-SGTR-1 Step 10 RCS cooldown with steam dumps unavailable (permissive light NOT illuminated on 2RP4). Table B determines target temp from ruptured SG pressure: 1045 psi → 503°F. Condenser steam dumps unavailable → cooldown using MS10s on intact SGs (21, 22, 23). Lower MS10 setpoints to fully open for max-rate cooldown. When hottest CET reaches 503°F, stop cooldown by matching MS10 setpoints to current SG pressures. Do NOT dump steam from ruptured 24 SG.
JPM — 2019 Sim-c
Step 19 RCS depressurization using normal spray during SGTR on 22 SG. Open spray valves 2PS1 and 2PS3. Monitor depressurization against Table D criteria (RCS pressure < ruptured SG pressure AND PZR level > 11%). When Table D conditions met (CUE: PZR level 79% and rising), close spray valves per CAS at Step 19.1. 2PS3 fails to close (alternate path). Step 19.4: spray valve not closed → STOP 21 and 23 RCPs to eliminate spray flow path through 2PS3. RCS pressure stops dropping (rising after RCP stop). Proceed to Step 27.
Scenario — 2018 #1
EOP-SGTR-1 entered from EOP-TRIP-1 after 24 SG tube rupture (650 gpm). Isolation of 24 SG: 24MS10 set to 1045 psig and closed, 24MS167, 24MS18, 24MS7, 24GB4 closed. Feed isolation: 24AF21 and 24AF11 closed. Dispatch to close 24SG (2SS339) and shift gland sealing steam to alternate IAW S2.OP-SO.GS-0001. RCS cooldown target from Table B: SG press >1000 psig = 503 F CETs. PO initiates cooldown using steam dumps at 25% demand in MS Pressure Control or intact MS10s. CT#2 (CT-19): crew must stop cooldown when hottest CETs < target temp to prevent transition out of SGTR-1. Note: 2PR6 power removed earlier (PZR pressure channel failure) — CRS may direct restoring power for subsequent RCS depressurization.
Exam — 2018 Q57
SI termination during SGTR-1: the reason ECCS flow is terminated is to prevent overfill of the ruptured SG (not the pressurizer). CAS for reestablishing ECCS flow: PZR level cannot be maintained ≥ 11% OR Subcooling ≤ 0°F. The logic is OR — either condition triggers ECCS restart. Trap: candidates may confuse overfill concern (it is the SG, not the PZR) or incorrectly believe ONLY PZR level (without the subcooling criterion) triggers ECCS restart.

Connections