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SALEM STUDY SYSTEM
Abnormals > AB.ROD-0003 — Continuous Rod Motion

AB.ROD-0003 — Continuous Rod Motion

⚠️ DRAFT

AB.ROD-0003 — Continuous Rod Motion

Purpose

Provides operator actions for responding to uncontrolled or continuous rod motion, including rod control system failures, failed Tavg channels, and failed NIS channels.

Key Actions / Information

  • Step 3.1: Place rod bank selector switch in Manual
  • Step 3.2: Verify rod motion stops (if not, trip the reactor)
  • Step 3.5: Adjust rods in manual to control Tavg within 1.5F of Tprogram
  • Step 3.9: Determine if a Tavg channel failed high or low
  • Step 3.10: Return PZR level to program (take Master Flow Controller to manual)
  • Steps 3.11-3.12: Defeat deviation alarms and select valid recorder channels
JPM — 2023 Sim-g
Failed high Tavg channel response: recognize unwarranted rod insertion (rods stepping in with no runback), take rods to manual. Restore Tavg within 1.5F of Tprogram by withdrawing rods. Stabilize PZR level by placing Master Flow Controller in manual. Defeat BOTH Differential Temperature AND Average Temperature deviation alarms on 2CC2 for the affected loop, then select a valid recorder channel (Channel 2, 3, or 4) for both parameters.
JPM — 2023 Sim-a
During rod surveillance (S2.OP-ST.RCS-0001), after returning the rod bank selector switch to AUTO, if unexpected continuous rod insertion occurs with no runback in progress — place switch in Manual. If rod motion does NOT stop, manually trip the reactor.
JPM — 2022 Sim-a
During rod surveillance (S2.OP-ST.RCS-0001), after placing rod bank selector switch in AUTO at step 4.1.11.3, uncontrolled rod insertion occurs (rods insert in both AUTO and MANUAL). Applicant must recognize rods continue inserting after placing switch in Manual and manually trip the reactor.
Scenario — 2022 #1
Event 3: 24 Loop Cold Leg RTD fails high causing continuous rod insertion. RO verifies no turbine runback in progress and places rods in Manual. CRS enters AB.ROD-0003. RO places MFC in Manual, reports various 2CC2 console alarms (RC Loop Tavg Deviation, Tavg-Tref Deviation, RC Tavg Hi or Lo-Lo, RC Loops DT Dev). CRS directs RO to adjust rods to maintain Tavg within 1.5 deg of T program, stop dilution, and return PZR level to program. RO defeats 24 loop RC DT and Average Temperature on 2CC2, selects alternate channel. After restoring rods and placing in Auto, CRS enters TS 3.3.1.1 Action 6 and TS 3.3.2.1.b Action 19 (place channel in tripped condition within 72 hours). CRS initiates S2.OP-SO.RPS-0002.
Scenario — 2020 #2
Event 4: 24 Loop Cold Leg RTD fails high (value 630 F) causing continuous rod insertion. RO reports no turbine runback. Places rods in Manual — motion stops. CRS enters AB.ROD-0003. RO places MFC in Manual, reports 2CC2 console alarms (Tavg Deviation, Tavg-Tref Deviation, RC Tavg Hi/Lo-Lo, DT Dev). Defeats 24 loop DT and Tavg on 2CC2, selects operable channel. Restores rods to Auto after Tavg within 1.5 degrees of Tref. CRS enters TS 3.3.1.1 Action 6 and TS 3.3.2.1.b Action 19 (72 hours each). CRS initiates S2.OP-SO.RPS-0002.
Scenario — 2020 #5
2PT-505 turbine inlet pressure channel fails low causing continuous rod insertion at 72 steps per minute. RO places rod control in Manual — rod motion stops. CRS enters AB.ROD-0003. RO maintains Tavg within 1.5 F of Tref using manual rod control. PO identifies PT-505 as the failed channel. PO places main steam dumps in MS Pressure Control-Auto. CRS enters TS 3.3.2.1.b Action 19 (72 hours). CRS initiates S2.OP-SO.RPS-0006 for turbine channel trip/restoration. RO withdraws control rods to ARO position.
JPM — 2020 Sim-c
During rod surveillance at Step 5.1.11.C, when rod bank selector switch placed in AUTO, continuous rod insertion occurs in both AUTO and MANUAL. Operator announces rods stepping in with no runback, places switch to Manual — rod motion does NOT stop. Recognizes situation and manually trips the reactor. Same discriminating step concept tested across 2020, 2022, and 2023 exam cycles.
Exam — 2019 Q67
Entry conditions: rods withdraw OR insert a MINIMUM of 3 steps at steady state conditions. 2 steps of rod motion can occur from process noise (per the AB.ROD-0003 basis) and does NOT warrant procedure entry. The entry threshold is 3 steps, not 2. Entry applies to BOTH withdrawal and insertion — not withdrawal ONLY.
Scenario — 2018 #2
22 RC Loop Tavg Channel fails high at 40% power. Rods step in unexpectedly (Tavg/Tref deviation). RO reports no turbine runback, places rod control in Manual. OHAs E-8 (Rod Insertion Lo) and E-16 (Rod Insertion Lo-Lo). CRS enters AB.ROD-0003. RO identifies 22 RC Loop Tavg channel failed high. Adjusts rods to maintain Tavg within 1.5 deg of program. Defeats 22 loop dT and Tavg on 2CC2, selects alternate channel. Restores rods to ARO, returns rod control to Auto. CRS enters TSAS 3.3.1.1 Action 6 (6 hr) and 3.3.2.1.b Action 19 (6 hr). CRS initiates S2.OP-SO.RPS-0002 to place 22 RC Loop Tavg in tripped condition.

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