Q29 — CVCS Boration/Dilution
004 G2.1.32 (3.8)
Given:
• Salem Unit 2 is at 100% Power.
• All systems are in normal alignment and in Automatic.
• 21 Mixed Bed Demineralizer is in service.
• A malfunction occurs with the 2CC71, Letdown HX Temperature Controller, while operating in AUTO.
• 2TI130A, Letdown Temperature, indicates 120 °F and RISING.
Which ONE of the following completes both statements?
1. Based on the above condition, RCS boron concentration will _(1)_.
2. What is the expected operator response to prevent exceeding procedural limits, assuming the 2CC71 does not respond?
• Salem Unit 2 is at 100% Power.
• All systems are in normal alignment and in Automatic.
• 21 Mixed Bed Demineralizer is in service.
• A malfunction occurs with the 2CC71, Letdown HX Temperature Controller, while operating in AUTO.
• 2TI130A, Letdown Temperature, indicates 120 °F and RISING.
Which ONE of the following completes both statements?
1. Based on the above condition, RCS boron concentration will _(1)_.
2. What is the expected operator response to prevent exceeding procedural limits, assuming the 2CC71 does not respond?
A. 1) rise
2) Ensure 2CV21 diverts to VCT
2) Ensure 2CV21 diverts to VCT
B. 1) rise
2) Ensure 2CV35 diverts to Hold-up Tanks
2) Ensure 2CV35 diverts to Hold-up Tanks
C. 1) lower
2) Ensure 2CV21 diverts to VCT
2) Ensure 2CV21 diverts to VCT
D. 1) lower
2) Ensure 2CV35 diverts to Hold-up Tanks
2) Ensure 2CV35 diverts to Hold-up Tanks
▶ Show Answer & Explanation
✓ A. Correct. Letdown temperature rising will result in the demineralizer releasing boron into the RCS and raising RCS boron concentration. If letdown temperature continues to rise, then the operator should ensure that the 2CV21 automatically diverts to the VCT to bypass the demineralizers when letdown temperature reaches 136 °F. The operator can manually select 2CV21 to divert to VCT if the auto function fails. S2.OP-SO.CVC-0012 states a Limitation of 140 °F to prevent resin damage.
✗ B. Incorrect. First part is correct. Second part is incorrect. The 2CV35 is downstream of the demineralizers and therefore will not bypass the demineralizers. 2CV35 diverts to CVCS HUT on only a high VCT level. Plausible because the operator may incorrectly determine that the 2CV35 is used to bypass the demineralizers.
✗ C. Incorrect. First part is incorrect. RCS boron will be released on rising letdown temperature. Second part is correct.
✗ D. Incorrect. First part is incorrect. RCS boron will be released on rising letdown temperature. Second part is incorrect. The 2CV35 is downstream of the demineralizers and therefore will not bypass the demineralizers. 2CV35 diverts to CVCS HUT on high VCT level. Plausible because the operator may incorrectly determine that the 2CV35 is used to bypass the demineralizers.
Ref: NOS05CVCS00-18, S2.OP-SO.CVC-0012 | LO: NOS05CVCS00-18, Objective 16 | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: CVCS, RCS
- Related procedures: S2.OP-SO.CVC-0012 — Purification and Chemistry Control
- Related exam: 2022 NRC Written Exam