Q86 — Accumulator Boron Concentration / LCO 3.5.1 / LCO 3.0.3
006 ECCS-AA2.10 (3.9)
REFERENCE PROVIDED
Given:
• Unit 2 is at 100% Power and stable
At time 13:00:00
• The Accumulators have been sampled per S2.OP-ST.SJ-0008 (Emergency Core Cooling - Accumulators) with the following results:
In accordance with LCO 3.5.1 (ACCUMULATORS), which ONE of the following completes the statements below?
Based on the sample results, _(1)_ Accumulator(s) is/are inoperable.
If the inoperable Accumulator(s) can NOT be restored to OPERABLE status, then the Unit is required to be in HOT STANDBY within a MAXIMUM of _(2)_ hours.
Given:
• Unit 2 is at 100% Power and stable
At time 13:00:00
• The Accumulators have been sampled per S2.OP-ST.SJ-0008 (Emergency Core Cooling - Accumulators) with the following results:
| Accumulator | 21 | 22 | 23 | 24 |
|---|---|---|---|---|
| Boron Concentration (ppm) | 2175 | 2550 | 2400 | 2350 |
In accordance with LCO 3.5.1 (ACCUMULATORS), which ONE of the following completes the statements below?
Based on the sample results, _(1)_ Accumulator(s) is/are inoperable.
If the inoperable Accumulator(s) can NOT be restored to OPERABLE status, then the Unit is required to be in HOT STANDBY within a MAXIMUM of _(2)_ hours.
A. _(1)_ 1 _(2)_ 7
B. _(1)_ 1 _(2)_ 78
C. _(1)_ 2 _(2)_ 7
D. _(1)_ 2 _(2)_ 78
▶ Show Answer & Explanation
✓ C. Correct. For Part 1 and IAW LCO 3.5.1, the boron concentration limit is between 2200 - 2500 ppm. Consequently, there are 2 Accumulators that are inoperable (21 at 2175 ppm is below 2200 ppm, 22 at 2550 ppm is above 2500 ppm). For Part 2, since BOTH accumulators are inoperable, LCO 3.0.3 is applicable and the Unit is required to be in HOT STANDBY within a MAXIMUM of 7 hours (1 hour to initiate action + 6 hours to HOT STANDBY).
✗ A. For Part 1, the candidate could incorrectly recall the boron concentration limits of LCO 3.5.1 and conclude that only 1 Accumulator is inoperable. For Part 2, the candidate could fail to recognize that LCO 3.0.3 is in effect. Consequently, the candidate would then incorrectly conclude that the Unit is required to be in HOT STANDBY within a MAXIMUM of 7 hours.
✗ B. For Part 1, the candidate could incorrectly recall the boron concentration limits of LCO 3.5.1 and conclude that only 1 Accumulator is inoperable. Part 2 is correct.
✗ D. Part 1 is correct. For Part 2, the candidate could fail to recognize that LCO 3.0.3 is in effect. Consequently, the candidate would then incorrectly conclude that the Unit is required to be in HOT STANDBY within a MAXIMUM of 78 hours.
Ref: LCO 3.5.5 (redacted reference provided) | LO: NOS05ECCS00-09 (EMERGENCY CORE COOLING SYSTEM) — 10. Given a situation dealing with ECCS operability, examine the situation and apply the appropriate Technical Specification action. | Source: New | Cognitive: Higher
Connections
- Related systems: ECCS
- Related tech specs: TS 3/4.5 — ECCS, TS 3/4.0 — Applicability
- Related exam: 2018 NRC Written Exam