ML24215A187

LLC, Response to SDAA Audit Question Number A-16.1.1-2

ML24215A187
Person / Time
Site:	05200050
Issue date:	08/02/2024
From:	NuScale
To:	Office of Nuclear Reactor Regulation
Shared Package
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References
LO-169995
Download: ML24215A187 (1)

Text

Response to SDAA Audit Question Question Number: A-16.1.1-2 Receipt Date: 09/18/2023 Question:

US460 generic TS Section 1.1, Table 1.1-1, annotates the title of MODE 3, Safe Shutdown with footnote (a), which states, Any CRA [control rod assembly] capable of withdrawal, or any CVCS [chemical and volume control system] or CFDS [containment flooding and drain system]

connection to the module not isolated. This defines the module-connected system isolation condition that determines when the module is in MODE 3 or MODE 4.

(1) Identify where the FSAR describes how isolation of the CFDS and CVCS is expected to normally be accomplished. This operational detail should be clear in order to determine that the footnotes isolation condition of these systems is established, and in which MODE the module is.

(2) Entry into MODE 4 also requires having established (presumably by boration using the CVCS) a core reactivity condition of keff < 0.95.

(a) Identify wherethe FSAR describes the reactor coolant system temperature assumed for calculating the boron concentration needed to satisfy the required reactivity condition for entry into MODE 4?

(b) Explain how this assumed temperature value is consistent with the minimum bulk temperature specified for the ultimate heat sink by LCO 3.5.3.b.

Response

Owners administrative and operational procedures control isolation of the containment flooding and drain system and chemical and volume control system and establishment of shutdown margin. Technical Specifications contain sufficient information to make the intent clear. The operating fleet controls details on completion of isolation, or calculation of shutdown margin, which are subject to review and oversight by the NRC Regional staff and the onsite resident NuScale Nonproprietary NuScale Nonproprietary

inspectors. Discussion of owner administrative and operational guidance is outside the scope of the SDAA.

No changes to the SDAA are necessary.

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