ML20127L045
| ML20127L045 | |
| Person / Time | |
|---|---|
| Site: | 05200004 |
| Issue date: | 01/18/1993 |
| From: | Marriott P GENERAL ELECTRIC CO. |
| To: | Joshua Wilson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| MFN-008-93, MFN-8-93, NUDOCS 9301260315 | |
| Download: ML20127L045 (5) | |
Text
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y GE NucIcar Energy January 18,1993
,,,,e MFN No 908-93 Docket STN 52-004 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Jerry N. Wilson, Acting Director Standardization Project Directorate
Subject:
Use of Modular Construction in the SBWR Ih
Reference:
Draft Topics of Interest Related to Modular Construction Techniques, Faxed from y gy,.
NRC to J. C. Baechler, December 15,1992 p
Dear Mr. Wilson:
The referenced fax requested information concerning the use of modular construction in t' e SBWR. Enclosed is information which addresses the concerns outlined in the reference.
Further communication and meetings may be necessary to clarify issues. GE proposes that these meetings be held during the month of March.
Sincerely, F
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/
P. W. Marriott, Manager Safety & Licensing M/C 444, (408) 925-6948 Enclosure 230032 g
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-9301260315 930118
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PDR ADOCK 05200004 h
The following information is provided in response to questions regarding modular construction received from the NRC on December 15,1992.
Item 1.
Description of types of structural modules to be used, including:
j Modules fabricated off site with final assembly at an on-site shop.
- Modules fabricated entirely on site in a module assembly area.
l
Response
Modular construction details are still being developed and specific design structural modules are not yet finalized. These will be j
available for the appropriate phases of the design and j
construction process. One of the agreed upon characteristics is that the size of any off-site fabricated module must be suitable for rail or truck shipment. See the attachment for a summary of modularization details.
Types of structural modules used are:
a Rebar cages with liner plates for containment & RPV pedestal walls.
j a
Rebar cages with steel beam and metal deck for floor slabs.
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m Structural steel modules for-vent wall structure and j
diaphragm floor stab.
j Rebar cages for the isolation condenser pool girders and u
basemat.
i There will be no precast concrete modules for major structural elements.
Item 2.
Description of erection plans.
1
Response
The erection plans have not been fully developed, but will be l
available for the appropriate phases of the construction program as needed.
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Page 1 of 4
Item 3.
Description of QC/QA program for on site storage.
Response
The details of the QC/QA programs for on-site storage have not been developed, but will meet all applicable regulations and industry standards as appropriate, item 4.
Difference in analysis and design criteria resulting from the use of modular construction.
Response
There are no changes to the loading, load combinations and structural acceptance criteria due to modularization. However, criteria for the structural design of modules will be developed as appropriate.
Item 5.
Experience in the design, etc., of structural modules.
Response
Structural module design experience is available from architect engineers.
Item G.
Discussion of codes, standards, tests and practices to be used to address the following parameters:
Ductility, stiffness and stiffness degradation of modules and structures.
Strength and reliability of joints and connections of modules.
Damping values for seismic analysis of modules.
QA/QC for design, fabrication, shipping, erection, ISI and maintenance of modules.
Functional sensitivity of modules to the above parametors.
DBA structural safety margins and ultimate structural capacities for use in PRAs.
Verification tests defined, if needed.
Page 2 of 4
Access to Japanese testing results.
Response
a Since no precast concrete modules are anticipated to be used, degradation of ductility and stiffness due to E
modularized construction is not expected.
m The strength of the joints and the connections between the modules are the same as the monolithic construction. The joints between structural steel and reinforced concrete members can be built to the required strength / reliability specifications. However, the actual design and construction of the joints between the structural steel and reinforced concrete members requires detailed design and evaluation.
This will be performed as module design is developed, as applicable, a
For the different kinds of modules being considered, such as rebar cages and structural steel, no changes in the damping values are anticipated due to modular construction.
m "lSI" and mainten6nce are not applicable for structural modules OA/QC for design, fabrication, shipping and erection is to be developed as required.
m The kind of structural modules anticipated to be used for SBWR, such as rebar and structural steel, are not functionally 4
sensitive to the parameters such as damping, stiffness, and ductility.
m Structural ultimate capacity is not affected by the proposed modularized construction, therefore the margins arc not affected due to utilization of modular construction techniques, a
Testing for components, such as connections between modules, has not been identified, but will be considered at the appropriate stage of module design development as applicable.
m Review of the Japanese construction and testing results may not be beneficial due to the differences in the modular construction techniques employed (rebar case versus steel Page 3 of 4
Q modules). The current Japanese nuclear construction i
project is Kashiwazaki Kariwa 6/7. However, the reinforced concrete containment vessel construction for these plants is a conventional one. The containment liner uses modular construction.
1 I
item 7.
Discussion of ITAACs for construction of modular units.
l
Response
l Conceptually, the construction of a modular unit, whether.off-site or on-site, will be the same as a monolithic structure. If ITAACs are j
not required for monolithic structure, none are needed for l
modular structures.
Item 8.
Plans for accessibility for inservice inspection, maintenance, and
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repair of modular units during operation.
I Response-j inservice inspection, maintenance and repair of modules is not anticipated for the structural modules any more than conventional i
construction.
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