Q10 — RCP Seal Injection / Seal Inlet Temperature Limit
APE 56 AK3.02 (4.1)
Given:
• Salem Unit 2 experienced a Loss of Off-Site Power
• The crew is performing S2.OP-AB.LOOP-0001
• ALL Charging Pumps on Unit 2 are unavailable
• 13 Charging Pump from Unit 1 is being aligned to supply charging flow to Unit 2
• Power to the 4KV Group Buses have been restored
• RCP seal inlet temperatures: 21 RCP - 227°F, 22 RCP - 220°F, 23 RCP - 219°F, 24 RCP - 221°F
Based on the above conditions, restoring seal injection flow to the RCPs (1) permitted. The reason for checking RCP seal inlet temperatures is to prevent (2).
• Salem Unit 2 experienced a Loss of Off-Site Power
• The crew is performing S2.OP-AB.LOOP-0001
• ALL Charging Pumps on Unit 2 are unavailable
• 13 Charging Pump from Unit 1 is being aligned to supply charging flow to Unit 2
• Power to the 4KV Group Buses have been restored
• RCP seal inlet temperatures: 21 RCP - 227°F, 22 RCP - 220°F, 23 RCP - 219°F, 24 RCP - 221°F
Based on the above conditions, restoring seal injection flow to the RCPs (1) permitted. The reason for checking RCP seal inlet temperatures is to prevent (2).
A. (1) is NOT (2) actuation of the Safe Shutdown seal
B. (1) is (2) actuation of the Safe Shutdown seal
C. (1) is (2) damage to #1 seal
D. (1) is NOT (2) damage to #1 seal
▶ Show Answer & Explanation
✗ A. Incorrect. While seal injection is NOT permitted (correct for part 1), the reason is to prevent damage to the #1 seal from thermal shock, not to prevent actuation of the Safe Shutdown seal. Safe Shutdown Seal actuation is monitored by seal OUTLET temperature (limit 190°F), not seal inlet temperature.
✗ B. Incorrect. Seal injection is NOT permitted (part 1 is wrong). Also, the reason for checking seal inlet temperature is to prevent #1 seal damage, not Safe Shutdown seal actuation.
✗ C. Incorrect. While preventing damage to #1 seal is the correct reason (part 2), seal injection is NOT permitted since 21 RCP seal inlet temperature is 227°F, which exceeds the 225°F limit.
✓ D. Correct. Per S2.OP-AB.LOOP-0001, Attachment 10, if ANY one of the RCP seal inlet temperatures is ≥ 225°F, then restoring seal injection flow to the RCPs is NOT permitted. Based on 21 RCP seal inlet temperature of 227°F (≥ 225°F), seal injection must be isolated prior to starting 13 charging pump. The reason is to prevent thermal shock from restoring cold seal injection water and damage to the RCP #1 seal. Note: Safe Shutdown Seal actuation is monitored by seal OUTLET temperature (limit 190°F), not seal inlet temperature.
Ref: S2.OP-AB.LOOP-0001 (R34) | LO: NOS05ABLOP1-09, Obj 2 | Source: Bank - Salem | Cognitive: Comprehension/Analysis
Connections
- Related systems: RCPs, CVCS
- Related procedures: AB.LOOP-0001 — Loss of All Offsite Power
- Related exam: 2023 NRC Written Exam