ML24215A027

LLC, Response to Sdaa Audit Question Number A-3.7.2-14

ML24215A027
Person / Time
Site:	05200050
Issue date:	08/02/2024
From:	NuScale
To:	Office of Nuclear Reactor Regulation
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Download: ML24215A027 (1)

Text

Response to SDAA Audit Question Question Number: A-3.7.2-14 Receipt Date: 07/10/2023 Question:

Section 3.7.2.8 states "A failure of a nearby structure could adversely affect the SC-I portions of the RXB and CRB. These nearby structures are assessed (or analyzed if necessary) to ensure that there is not a credible potential for adverse interactions. Figure 1.2-4 provides a site plan showing the standard plant layout."

(a) Figure 1.2-4 shows "Cutaway View of NuScale Power Module", and Figure 1.2-1 shows "Conceptual Site Layout." Please update the figure number in the quoted statement above, as applicable.

(b) Summarize in the FSAR the assessment of potential for adverse seismic interactions of non-seismic category I structures with seismic category I structures in the US460 standard design; specifically, between the Radioactive Waste Building (RWB) and the RXB, and the non-SC-I portion of the CRB and the SC-I portion of the CRB.

Response

Item (a):

NuScale revises the reference in US460 Standard Design Approval Application (SDAA) Section 3.7.2.8 to Figure 1.2-1 as shown in the attached markup.

Item (b):

The US460 SDAA defers to the COL applicant for assessment of potential for adverse seismic interactions of non seismic category 1 (non-SC-I) structures with SC-I. COL Item 3.7-7 NuScale Nonproprietary NuScale Nonproprietary

addresses the requirement to ensure that the non-SC-I portions of the buildings do not adversely affect the SC-I portions.

COL Item 3.7-7: An applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to a site-specific safe shutdown earthquake will not collapse and adversely affect Seismic Category I portions of the Reactor Building and Control Building.

Markups of the affected changes, as described in the response, are provided below:

NuScale Nonproprietary NuScale Nonproprietary

NuScale Final Safety Analysis Report Seismic Design NuScale US460 SDAA 3.7-109 Draft Revision 2 3.7.2.5.5 Control Building In-Structure Response Spectra The ISRS and displacements are calculated at the following floor locations:

Elevation 100 ft (basemat)

Elevation 123 ft (middle floor)

Elevation 153 ft 3 inches (roof)

Figure 3.7.2-98 through Figure 3.7.2-100 show the floor nodes' locations.

Figure 3.7.2-101 through Figure 3.7.2-106 show the ISRS.

3.7.2.6 Three Components of Earthquake Motion The three components of earthquake motion are developed as separate time histories as discussed in Section 3.7.1.1. When performing a harmonic analysis, the representative response time history of interest of the SSC is obtained by performing separate analyses for each of the three components of earthquake motion (and summing them algebraically). In the case of non-linear time-history analysis, for stability evaluation for example, the three components of earthquake motion are applied simultaneously. In the latter case, the three components of earthquake motion are statistically independent.

Seismic demand is obtained for the three orthogonal (two horizontal and one vertical) components of earthquake motion in accordance with ASCE 4-16 (Reference 3.7.2-6). The orthogonal axes are aligned with the principal axes of the structure.

3.7.2.7 Combination of Modal Responses Modal responses in seismic response analysis is combined in accordance with RG 1.92, "Combining Modal Responses and Spatial Components in Seismic Response Analysis."

3.7.2.8 Interaction of Non-Seismic Category I Structures with Seismic Category I Structures Audit Question A-3.7.2-14 A failure of a nearby structure could adversely affect the SC-I portions of the RXB and CRB. These nearby structures are assessed (or analyzed if necessary) to ensure that there is not a credible potential for adverse interactions.

Figure 1.2-1Figure 1.2-4 provides a site plan showing the standard plant layout.

The non-SC-I structures that are adjacent to the Seismic Category I RXB and CRB are the Radioactive Waste Building (SC-III), that is adjacent to RXB and the SC-II portion of the CRB that is directly to the north of the SC-I portion of the CRB.

COL Item 3.7-7:

An applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to a site-specific safe shutdown earthquake will not collapse and adversely affect Seismic Category I portions of the Reactor Building and Control Building.