ML24215A199
| ML24215A199 | |
| Person / Time | |
|---|---|
| Site: | 05200050 |
| Issue date: | 08/02/2024 |
| From: | NuScale |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML24215A000 | List:
|
| References | |
| LO-169995 | |
| Download: ML24215A199 (1) | |
Text
Response to SDAA Audit Question Question Number: A-16.3.5.1-1 Receipt Date: 09/18/2023 Question:
The LCO 3.5.1, ECCS, and LCO 3.5.2 DHRS, Applicability includes MODE 3 and not PASSIVELY COOLED.
This implies equivalently MODE 3 with any RCS indicated temperature < 345 deg F because to be in MODE 3 above 345 deg F requires being PASSIVELY COOLED.
Consider phrasing this Applicability to say:
MODE 3 with any RCS indicated temperature < 345 F and not PASSIVELY COOLED.
Also, if in MODE 3 and DHRS is providing PASSIVE COOLING, the LCO 3.5.2 Bases Applicability section explains that the DHRS is no longer required to be OPERABLE by LCO 3.5.2 because DHRS is in operation. If in MODE 3 with RCS indicated temperature 345 F and with one train of DHRS providing PASSIVE COOLING, is the other train required to be OPERABLE in a standby state (i.e., inlet valve closed) by LCO 3.5.2?
Response
NuScale revises the Technical Specifications 3.5.1 and 3.5.2 MODE 3 applicability to read:
MODE 3 with RCS indicated temperature < 345 F and not passively cooled The second train of DHRS would not be required to be operable in MODE 3 with RCS indicated temperature 345 F and with one train of the Decay Heat Removal System (DHRS) providing passive cooling, because LCO 3.5.2 is no longer applicable with the reactor passively cooled.
Markups of the affected changes, as described in the response, are provided below:
NuScale Nonproprietary NuScale Nonproprietary
ECCS 3.5.1 NuScale US460 3.5.1-1 Draft Revision 2 3.5 PASSIVE CORE COOLING SYSTEMS (PCCS) 3.5.1 Emergency Core Cooling System (ECCS)
LCO 3.5.1 Two reactor vent valves (RVV) and two reactor recirculation valves (RRV) shall be OPERABLE.
APPLICABILITY:
MODES 1 and 2, MODE 3 with RCS indicated temperature < 345 °F and not PASSIVELY COOLED.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. ------------NOTE -------------
Separate Condition entry is allowed for each valve.
One RVV inoperable.
OR One RRV inoperable.
A.1 Restore valve to OPERABLE status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> B. Required Action and associated Completion Time not met.
OR Two RVVs inoperable.
OR Two RRVs inoperable.
B.1 Be in MODE 2.
AND B.2 Be in MODE 3 and PASSIVELY COOLED.
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours
DHRS 3.5.2 NuScale US460 3.5.2-1 Draft Revision 2 3.5 PASSIVE CORE COOLING SYSTEMS (PCCS) 3.5.2 Decay Heat Removal System (DHRS)
LCO 3.5.2 Two DHRS loops shall be OPERABLE.
APPLICABILITY:
MODES 1 and 2, MODE 3 with RCS indicated temperature < 345 °F and not PASSIVELY COOLED.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One DHRS loop inoperable.
A.1 Restore DHRS loop to OPERABLE status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> B. Required Action and associated Completion Time not met.
OR Both DHRS loops inoperable.
B.1 Be in MODE 2.
AND B.2 Be in MODE 3 and PASSIVELY COOLED.
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours