AB.CHEM-0001 — Secondary Chemistry Abnormality
Purpose
Provides operator actions for responding to secondary chemistry abnormalities, including condenser tube leaks and gross tube failures.
Key Actions / Information
Exam — 2023 Q60
A gross Condenser Tube Failure/Leak is indicated by rapidly rising Secondary Plant Chemistry recorder trends, 2CC1 and OHA alarms. It is defined as: 30 ppb Condensate Pump Disch sodium with condensate polisher in service, OR 2 ppb Condensate Pump Disch sodium with condensate polisher out of service, OR a rapidly increasing Condensate Pump discharge sodium expected to exceed those limits. Alarms confirming a CW waterbox tube leak: Dissolved Oxygen Hi, Condensate Pump Disch Sodium Hi, and Hotwell Outlet Conductivity Hi. Hydrazine Lo is NOT expected from a CW tube leak.
Exam — 2020 Q95
With Condensate Polisher unavailable and Condensate Pump Discharge sodium ≥ 2 ppb (15 ppb in the scenario): Attachment 3 actions apply. Required actions: reduce SGBD flow to minimum, Emergency Trip the affected Circulator (21A), and commence a plant shutdown as quickly as possible. With polishers bypassed and sodium > 2 ppb, SG chemistry degrades significantly — maximize SGBD is WRONG (reduce to minimum). Action Level 2 limits (reduce to ≤ 50%) apply with polishers in service. Stopping the circulator and transferring SGBD without immediate shutdown applies to Action Level 1 values.
Scenario — 2019 #1
21A condenser tube leak at 4% power (Event 4). Console alarm HOTWELL OUTLET CONDUCTIVITY HI. CRS enters AB.CHEM-0001 and directs CAS. Crew checks secondary chemistry recorders on 2RP5, identifies 21A condenser as affected hotwell from rising Conductivity and Dissolved Oxygen. Attachment 1 CAS Step 1.0 met for condenser tube failure/leak. Attachment 2 conditions met for Gross Condenser Tube Failure — Emergency Trip CW pump.
Connections
- Related systems: Feed & Condensate, Circ Water
- Related exam questions: 2023 Q60, 2020 Q95
- Related scenarios: 2019 Scenario 1 — Power Ascension / LOCA Outside Containment
- Related exam: 2019 NRC Operating Exam, 2023 NRC Written Exam, 2020 NRC Written Exam