Q90 — R18 Detector Failure / Liquid Release
073A2.02 (3.2)
Given:
• Unit 2 is at 100% Power.
• 21 CVCS Monitor Tank is in a recirculation lineup in accordance with S2.OP-SO.WL-0001, Release of Radioactive Liquid Waste from 21 CVCS Monitor Tank, in preparation for Chemistry Sampling and future release authorization by the Control Room Supervisor.
Complete the following statements concerning the expected response to the instrument failure and additional actions required in accordance with S2.OP-SO.WL-0001 to continue the liquid radioactive release based on the instrument failure.
(1) The 2R18 experiences a detector failure causing the monitor to fail LOW. The 2WL51, Liquid Release Stop Valve, __(1)__ automatically close.
(2) To continue the release, the CRS will verify 2FR1064, Radwaste Overboard Discharge Flow Recorder, is Operable __(2)__ perform two independent samples, independent release calculations, and independent discharge valve lineups.
• Unit 2 is at 100% Power.
• 21 CVCS Monitor Tank is in a recirculation lineup in accordance with S2.OP-SO.WL-0001, Release of Radioactive Liquid Waste from 21 CVCS Monitor Tank, in preparation for Chemistry Sampling and future release authorization by the Control Room Supervisor.
Complete the following statements concerning the expected response to the instrument failure and additional actions required in accordance with S2.OP-SO.WL-0001 to continue the liquid radioactive release based on the instrument failure.
(1) The 2R18 experiences a detector failure causing the monitor to fail LOW. The 2WL51, Liquid Release Stop Valve, __(1)__ automatically close.
(2) To continue the release, the CRS will verify 2FR1064, Radwaste Overboard Discharge Flow Recorder, is Operable __(2)__ perform two independent samples, independent release calculations, and independent discharge valve lineups.
A. (1) will NOT
(2) AND
(2) AND
B. (1) will
(2) OR
(2) OR
C. (1) will NOT
(2) OR
(2) OR
D. (1) will
(2) AND
(2) AND
▶ Show Answer & Explanation
✓ A. Correct. The R18 failing low will not cause the WL51 to close. S2.OP-SO.WL-0001(Q), Release of Radioactive Liquid Waste From 21 CVCS Monitor Tank ensures that if 2R18 is inoperable, then 2FR1064 must remain operable. (see steps 2.3, 3.4, and 3.5) Although the ODCM 3.3.3.8 allows flow rate to be estimated if the 2FR1064 is inoperable, the release procedure prevents both from being inoperable at the same time. ODCM 3.3.3.8 action b states; "exert best efforts to return the instrument to OPERABLE status within 30 days and, if unsuccessful, explain in the next radioactive effluents release report why the inoperability was not corrected in a timely manner."
✗ B. Incorrect. The first part is plausible because the candidate may remember that a high alarm on R18 will automatically close WL51. Incorrect as the R18 failed low. The second part is plausible because the candidate may remember that per the ODCM, 2FR1064 can be inoperable if flow rate is estimated at least once per 4 hours during actual releases. Incorrect as the release procedure specifically requires that if the R18 is inoperable, then the 2FR1064 must be OPERABLE. The second part is correct.
✗ C. Incorrect. The first part is correct. The second part is plausible because the candidate may remember that per the ODCM, 2FR1064 can be inoperable if flow rate is estimated at least once per 4 hours during actual releases. Incorrect as the release procedure specifically requires that if the R18 is inoperable, then the 2FR1064 must be OPERABLE.
✗ D. Incorrect. The first part is plausible because the candidate may remember that a high alarm on R18 will automatically close WL51. Incorrect as the R18 failed low. The second part is correct.
Ref: ODCM LCO 3.3.3.8 and Bases; S2.OP-SO.WL-0001 | LO: N/A | Source: New | Cognitive: Fundamental
Connections
- Related systems: Radiation Monitoring, Waste Liquid
- Related procedures: S2.OP-SO.WL-0001 — Release of Radioactive Liquid Waste
- Related tech specs: TS 3/4.3 — Instrumentation
- Related exam: 2020 NRC Written Exam