ML20077R667
| ML20077R667 | |
| Person / Time | |
|---|---|
| Site: | 05000605 |
| Issue date: | 08/19/1991 |
| From: | Rogers A GENERAL ELECTRIC CO. |
| To: | Chris Miller NRC, NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| EEN-9160, MFN-082-91, MFN-82-91, NUDOCS 9108230259 | |
| Download: ML20077R667 (5) | |
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GE Nuclear Energy August 19,1991 MFN No.082 91 Docket No. STN 50-605 EEN 9160 1
Document Control Desk l
U.S. Nuclear Regulatory Commission Washington, D.C. 20555 i
Attention:
Charles L Miller, Director I
Standardization and Non. Power Reactor Project Directorate
Subject:
Confirmation of AllWR Selsmic Design Adequacy Enclosed are thirty four (34) copies of the GE proposal pertaining to the methodology to confirm the adequacy of the AllWR seismic design. A summary of this proposal was presented at the OE/NRC meeting on the review of AllWR for aesign certification on July 16,1991 in Rockville, Maryland. The rationale for this proposal is provided below.
The seismic design of the A11WR standard plant is based on a 0.3g SSE together with RO 1.60 design response spectra for a wide range of site conditions. T.he current interface requirements for demonstrating the suitability of this site envelope design for a given site are given by eight conditions ~ in SSAR Section 3A.1 and site envelape parameters in SSAR Table 2.01 for soil properties and seismology.
OE recently received several inquiries from potential customers indicating that a few site enveloping parameters are marginally exceeded. llowever, there are no provisions in the SSAR to address what should be done in case one or more of the site specific conditions exceed the design envelope. Such deviations do not necessarily mean that the standardized design is unsuitable for a specific site because of the conservatism inherent in the seismic design. A confirmation of seismic design adequacy is, nevertheless, needed by a site specific evaluation. The purpose of this submittal is to document an evaluation procedure which the applicants referencing the AllWR design shall follow in the event any one of the site specific conditions are outside the design envelope. In addition to treating potential deviations, the evaluation procedure addresses all eight site dependent conditions.
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MIN No. 082 91 Docket No. STN 50 606 August 19,1991 Page 2 of 2 OE believes that by implementing this evaluation procedure, maximum value of the AllWR standard plant will be realized (i.e., modestly increasing the number of applicable sites) without compromising the plant seismic safety.
It is intended tLit OE will amend the SSAR accordingly in a future amendment.
Sincer ely,
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.snm A. E. Rogers, Acting Manager Regulatory and Analysis Services M/C 382, (408) 925-6948 cc: F. A. Ross (DOE)
D. C. Scaletti (NRC)
R. C. llerglund (OE)
J. F. Outrk (GE) o
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e Compliance with the envelope of AllWR blandard Plant site design parameters of Table 2.01 shalllie dernonst gd for design bases events. (See Subsection 2.2.1N h en-s essm i e iH S0RT g.
A l 23.2 Standara uniew Plan Characteristics identification and description of all differences from SRP Section 11 Acceptance Criteri. for site characteristics (as augmented by Table 2.1 1) shall be provided. Where such differences exist, the evaluation shall discuss how the alternate site characteristic is acceptable 23J CMC 2 Computer Code Calculations Compliance with acceptance criteria, data input and analysis of Subsection 2.2.2 for the determinatien of AllWR site acceptability for severe accidents shall be demonstrated.
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2.3.1.2 Seismic Design Parannters
. To confirm the seismic design adequacy of the standard plant, the applicants referencing the ABWR design shall demonstrate that the eight (8) site-dependent conditions specified in--Section 3A.1-are satisfied.
In meeting those eight conditions, the compliance with the site envelope parameters shown in Table 2.0-1 for soil properties and seismology is also established.
If there is any deviation of the eight site-dependent conditions, a site specific evaluation is required.
The type of evaluation will vary depending on the deviation.
If the deviation is for condition 1 (peak ground acceleration), 2 (ground response spectra), or 6 (shear wave velocity), a site specific SSE soil-structure interaction analysis (SSI) is required.
The calculated site unique responses are compared to the site-envelope responses defined in Section 3G.4 to confirm the seismic design adequacy of the standard plant according to the following procedures and acceptance criteria.
For Seismic Category I structures including the RPV and its internal components that are included in the SSI analysis models (1) Design adequacy is established if maximum structural responses in terms of force, moment, or acceleration are bounded by the Section 3G.4 responses (or the actual seismic loads considered in design if applicable) at key locations.
(2) If not, calculate resulting SSE stresses.
Design adequacy is confirmed if combined stresses due to SSE and other appropriate loads are w1 thin design code allowable limits.
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l For Seismic Category I equipment and piping whose seismic input is in the form of. floor response spectra:
o (1) Design adequacy is established if floor response
. spectra are bounded by Section 3G.4 spectra (or the actual spectra. considered in design if applicable) at key locations.
The site unique response spectra ttsed for comparison need not be broadened s1nce uncertainties in the structural-frequencies have been accounted for in the smooth broadened site envelope spectra.
(2) If not -examine whether the deviations are at major resonant frequencies of the component under i
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-If not, design adequacy is confirmed.
Otherwise, perfcrm analysis and/or testing to demonstrate that the acceptance criteria given in design specifications are met.
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If the soil properties of the alte vary very abruptly with depth (site-dependent condit1on 7),
a site specific SSE SSI analysis is required.
The evaluation proceduren and acceptance criteria specified above are applicable.
If the ao11 bearing cupacity at the alte la not adequate to l
accommodate the standard plant design loads (site-dependent condition 8),
the foundation material chall be removed and replaced with better material to achieve the required bearing capacity.
Alternatively, the applicant referencing the ADWH design may perform a site specific analyala to demonstrate that the site has an adequate bearing capacity against the site unique loads.
The site-dependent conditiono 3 (liquefaction potential) and 4 (fault displacement potential) require site specific investigation.
A alte specific evaluation is required if the embedment deptha-of Seismic Category I buildings deviate from thoue Efrom the standard plant design (alte-dependent condition 5).
The evaluation procedure and acceptance criteria are the name ao those defined above for the oite specific SSE SSI analysis.
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