AB.LOAD-0001 — Rapid Load Reduction
Purpose
Provides operator actions for performing a rapid load reduction when directed by other abnormal procedures or when plant/grid conditions require a fast but controlled power decrease.
Entry Conditions
- Directed by other abnormal procedures (e.g., AB.GRID-0001 during solar magnetic disturbance)
- Plant or grid conditions requiring rapid power reduction
Key Actions
- Perform load reduction at the rate specified by the directing procedure
- Coordinate turbine load reduction with reactor power reduction
- Monitor critical plant parameters during the transient
Exam — 2023 Q88
During a Solar Magnetic Disturbance (SMD) > K-5 intensity with excess MVAR condition, AB.GRID-0001 Attachment 2 directs a load reduction to <= 77.6% (942 MWe) at 15% per min using AB.LOAD-0001. Trap: both AB.GRID-0001 AND AB.LOAD-0001 are required — AB.GRID-0001 alone is insufficient.
Scenario — 2020 #1
Entered for turbine load reduction to less than 80% power due to condenser DTs exceeding 27 F following loss of 21A-23A CW pumps. RO initiates boration IAW S2.OP-SO.CVC-0006. PO initiates turbine load reduction IAW S2.OP-SO.TRB-0001.
Scenario — 2020 #3
Entered for load reduction to 85% following 23 Condensate Pump trip. RO initiates boration IAW S2.OP-SO.CVC-0006. PO initiates load reduction using turbine load control IAW S2.OP-SO.TRB-0001. RO maintains Tavg on program IAW Attachment 3. RO energizes all PZR heaters.
Scenario — 2019 #3
Entered from AB.COND-0001 during loss of condenser vacuum (Event 4). CRS directs load reduction to stabilize backpressure. RO calculates required boron addition, CRS verifies, RO commences boration. PO initiates load reduction using turbine load control at CRS-specified rate.
Scenario — 2018 #2
AB.LOAD-0001 entered for orderly unit shutdown after 35 gpm RCS leak exceeds TS limits. RO develops reactivity plan for shutdown and initiates boration. PO initiates turbine load reduction to 20% at CRS-specified rate. During load reduction, RCS leak worsens to LBLOCA.
Connections
- Related systems: 500KV, Main Turbine, Circ Water
- Related procedures: AB.GRID-0001 — Grid Disturbance, AB.CW-0001 — Circulating Water Malfunction, AB.COND-0001 — Loss of Condenser Vacuum
- Related exam questions: 2023 Q88
- Related scenarios: 2018 Scenario 2, 2019 Scenario 3 — ATWS / Stuck-Open PORV, 2020 Scenario 1 — Power Ascension / Station Blackout, 2020 Scenario 3 — ATWS / Feedwater Line Break
- Related exam: 2018 NRC Operating Exam, 2019 NRC Operating Exam, 2023 NRC Written Exam, 2020 NRC Operating Exam