Q25 — EOP-TRIP-7 Rediagnosis
W E01 EK3.2 (3.0)
Given:
- Unit 2 has completed all actions in 2-EOP-LOSC-1, Faulted Steam Generator Isolation, to isolate a steam leak on 21 steam generator.
- The crew has just transitioned to 2-EOP-TRIP-3, SI Termination.
- The crew now reports the following plant conditions:
○ PZR level is lowering.
○ RCS pressure is lowering.
○ ALL SG pressures are stable.
○ 21 SG WR level is rising.
○ 2R19A, SG Blowdown, radiation monitor is in alarm.
- The CRS is unsure of the transition to 2-EOP-TRIP-3 and enters 2-EOP-TRIP-7, Rediagnosis.
In accordance with 2-EOP-TRIP-7, which ONE of the following procedures will the crew transition to NEXT?
- Unit 2 has completed all actions in 2-EOP-LOSC-1, Faulted Steam Generator Isolation, to isolate a steam leak on 21 steam generator.
- The crew has just transitioned to 2-EOP-TRIP-3, SI Termination.
- The crew now reports the following plant conditions:
○ PZR level is lowering.
○ RCS pressure is lowering.
○ ALL SG pressures are stable.
○ 21 SG WR level is rising.
○ 2R19A, SG Blowdown, radiation monitor is in alarm.
- The CRS is unsure of the transition to 2-EOP-TRIP-3 and enters 2-EOP-TRIP-7, Rediagnosis.
In accordance with 2-EOP-TRIP-7, which ONE of the following procedures will the crew transition to NEXT?
A. 2-EOP-LOCA-1, Loss of Reactor Coolant
B. 2-EOP-LOSC-1, Faulted Steam Generator Isolation
C. 2-EOP-TRIP-1, Reactor Trip or Safety Injection
D. 2-EOP-SGTR-1, Steam Generator Tube Rupture
▶ Show Answer & Explanation
✓ D. Correct. IAW 2-EOP-TRIP-7 and the conditions given in the stem, conditions are not symptoms of a faulted or a loss of RCS, and therefore, the next procedure to transition to would be 2-EOP-SGTR-1 due to rising SG levels and SG high radiation. EOP-TRIP-3 only transitions to EOP-LOCA-1, LOCA-2, IOP-6 & 8 procedures and therefore, if the crew remains in EOP-TRIP-3 with the above condition, there will be no transition directed in the aforementioned EOPs to EOP-SGTR-1.
✗ A. Incorrect. Plausible because EOP-TRIP-7 allows transition to EOP-LOCA-1 and the operator may believe based on lowering PZR level and pressure that a LOCA is in progress and transition to 2-EOP-LOCA-1.
✗ B. Incorrect. Plausible because EOP-TRIP-7 allows transition to EOP-LOSC-1 and the operator may incorrectly believe that EOP-TRIP-7 will direct you back to procedure in effect which was EOP-LOSC-1.
✗ C. Incorrect. Plausible because the operator may incorrectly believe that EOP-TRIP-7 will direct you to EOP-TRIP-1 where diagnosis are performed for symptoms of a LOCA, SGTR and LOSC.
Ref: 2-EOP-TRIP-7, Rev 40 | LO: NOS05TRP007-03, Objective 1 | Source: Bank – Byron 2019 NRC RO25 | Cognitive: Comprehension/Analysis