Q95 — Abnormal Secondary Chemistry
G2.1.34 (3.5)
Given:
• Unit 2 is at 100% Power.
• Chemistry has removed the Condensate Polisher due to emergent issue and is NOT available for service.
Subsequently, the following alarms and indications are received in the Control Room:
• Bezel alarm CONDENSATE PUMP DISCH SODIUM HI.
• Bezel alarm HOTWELL OUTLET CONDUCTIVITY HI.
• Bezel alarm CONDENSATE PUMP DISCH CONDUCTIVITY HI.
• Condensate Pump Discharge sodium is 15 ppb.
• 21A Hotwell Cation Conductivity is 0.5 µS/cm and rising.
• Chemistry has validated a tube leak exists in the 21A Waterbox.
Assume the Chemistry parameters above continue over the next hour.
Which ONE of the following describes the actions required in accordance with S2.OP-AB.CHEM-0001, Abnormal Secondary Plant Chemistry?
[REFERENCE PROVIDED]
• Unit 2 is at 100% Power.
• Chemistry has removed the Condensate Polisher due to emergent issue and is NOT available for service.
Subsequently, the following alarms and indications are received in the Control Room:
• Bezel alarm CONDENSATE PUMP DISCH SODIUM HI.
• Bezel alarm HOTWELL OUTLET CONDUCTIVITY HI.
• Bezel alarm CONDENSATE PUMP DISCH CONDUCTIVITY HI.
• Condensate Pump Discharge sodium is 15 ppb.
• 21A Hotwell Cation Conductivity is 0.5 µS/cm and rising.
• Chemistry has validated a tube leak exists in the 21A Waterbox.
Assume the Chemistry parameters above continue over the next hour.
Which ONE of the following describes the actions required in accordance with S2.OP-AB.CHEM-0001, Abnormal Secondary Plant Chemistry?
[REFERENCE PROVIDED]
A. Maximize SGBD flow, Emergency Trip 21A Circulator, and reduce power to ≤ 50 % power within 24 hours.
B. Reduce SGBD flow to minimum, Emergency Trip 21A Circulator, and commence a plant shutdown as quickly as possible.
C. Adjust SGBD Flow per Chemistry, continue to monitor secondary chemistry, 21A Circulator can remain in service.
D. Stop 21A Circulator, transfer SGBD to 22 Condenser, reduce power to ≤ 83 %, and adjust SGBD Flow per Chemistry.
▶ Show Answer & Explanation
✓ B. Correct. With the Condensate Polisher unavailable, a large Condenser Tube Leak, and Condensate Pump discharge sodium levels ≥ 2 ppb, then actions IAW Attachment 3 are applicable. When polishers are bypassed and sodium is > 2 ppb, Steam Generator chemistry can significantly degrade, and immediate actions are required to commence a plant shutdown as quickly as possible.
✗ A. Plausible because the candidate may believe that raising SGBD will lower impurities. The second action is correct. Reducing load to < 50% is plausible as this would is directed by the procedure if Action Level 2 Limits are met.
✗ C. Plausible because the candidate may believe that maximizing blowdown will help improve the chemistry. Remaining action is plausible if the polisher is still available and the candidate missed the information about the abnormal reading being present for 1 hour.
✗ D. Plausible because these actions could be performed if after stopping the Circulator, SGBD sodium increased to Action Level 1 values.
Ref: S2.OP-AB.CHEM-0001(Q), Abnormal Secondary Plant Chemistry and Bases. | LO: N/A | Source: New | Cognitive: Comprehension
Connections
- Related systems: Feed & Condensate
- Related procedures: AB.CHEM-0001 — Secondary Chemistry Abnormality
- Related exam: 2020 NRC Written Exam