Q40 — CFCU Containment Temperature Rise
022000A1.01 (3.6)
Given:
• Unit 2 is at 100 % Power.
• Four (4) CFCUs are in service in HIGH speed.
• Containment temperature is 95 °F.
• Containment pressure is 0.10 psig.
Consider the below conditions and its impact to Containment Fan Coil Unit performance during normal plant operation.
Which of the following conditions could result in a RISE in containment temperature?
1. Running CFCUs in LOW speed.
2. Starting additional Service Water Pumps.
3. Increase in service water temperature.
4. Erosion of the flow orifice upstream of the SW223.
• Unit 2 is at 100 % Power.
• Four (4) CFCUs are in service in HIGH speed.
• Containment temperature is 95 °F.
• Containment pressure is 0.10 psig.
Consider the below conditions and its impact to Containment Fan Coil Unit performance during normal plant operation.
Which of the following conditions could result in a RISE in containment temperature?
1. Running CFCUs in LOW speed.
2. Starting additional Service Water Pumps.
3. Increase in service water temperature.
4. Erosion of the flow orifice upstream of the SW223.
A. 1 and 3 Only.
B. 2 and 4 Only.
C. 2, 3, and 4 Only.
D. 1, 2, 3, and 4.
▶ Show Answer & Explanation
✓ A. Correct. Running CFCUs in LOW speed will result in lower air flow (47000 cfm low speed vs 110000 cfm high speed) through the CFCUs and therefore reduce heat transfer across the cooling coils. Increase in SW temperature will result in a reduced heat transfer across the CFCU cooling coils.
✗ B. Starting additional SW Pumps will increase the SW header pressure and cause an increase of SW flow across the orifice thereby increasing heat transfer across the cooling coils. Erosion on the flow orifice will result in increased SW flow and thereby increased heat transfer across the cooling coils.
✗ C. Choices 2 and 4 are incorrect as stated above. Choice 3 is correct.
✗ D. Choices 2 and 4 are incorrect as stated above. Choices 1 and 3 are correct as stated above.
Ref: NOS05CONTMT-15, Containment and Containment Support Systems. UFSAR Sections 6.2 and 15.4. | LO: ELOs 3 & 4 | Source: New | Cognitive: Comprehension
Connections
- Related systems: CFCUs, Service Water, Containment
- Related exam: 2020 NRC Written Exam