Q58 — Subcooling Margin Monitor Inputs
017000K4.01 (3.4)
Which ONE of the following lists the parameters used by the Subcooling Margin Monitor to calculate subcooling margin?
A. RCS pressure and RCS hot leg temperatures.
B. PZR pressure and CET temperatures.
C. RCS pressure and CET temperatures.
D. PZR pressure and RCS hot leg temperatures.
▶ Show Answer & Explanation
✓ C. Correct. The temperature margin to saturation is calculated by the CETPS. The inputs to this calculation are the representative CET temperature, RCS pressure, Containment pressure, and Containment radiation level. (page 17 of Incore Instrumentation Lesson Plan)
✗ A. Incorrect. The first part is correct. The second part is plausible because the student may believe that RCS hot leg temperatures are used to calculate subcooling margin. Incorrect as the representative CET temperature is used in the calculation.
✗ B. Incorrect. Plausible because the student may believe that PZR pressure is used in the subcooling calculation. Incorrect because RCS wide range pressure is used, PZR pressure instrumentation is a narrow range indication, reading no lower than 1700 psig. The second part is correct.
✗ D. Incorrect. The first part is plausible because the student may believe that PZR pressure is used in the subcooling calculation. Incorrect because RCS wide range pressure is used, PZR pressure instrumentation is a narrow range indication, reading no lower than 1700 psig. The second part is plausible because the student may believe that RCS hot leg temperatures are used to calculate subcooling margin. Incorrect as the representative CET temperature is used in the calculation.
Ref: NOS05INCORE-05, Incore Instrumentation | LO: ELOs 7, 18, and 19 | Source: Bank, Salem Vision Database | Cognitive: Fundamental
Connections
- Related systems: Incores, RCS, Pressurizer & PRT
- Related exam: 2020 NRC Written Exam