ML20235U088
| ML20235U088 | |
| Person / Time | |
|---|---|
| Site: | 07100510 |
| Issue date: | 09/17/1987 |
| From: | Schwartz M LAWRENCE LIVERMORE NATIONAL LABORATORY |
| To: | Roberts J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-PROJ-M-37 28597, S87-197, NUDOCS 8710130353 | |
| Download: ML20235U088 (2) | |
Text
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RETURN IQ 39MS V8/ M Lawrence Uvermore National Laboratory f-~0 $ b NUCLEAR SYSTEMS SAFETY PROGRAM September 17,1987 S87-197 g
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RECEIVED Mr. John P. Roberts t
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SEP231987 )1 Office of Nuclear Material Safety and Safeguards
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SUBJECT:
Material Deviation for Castor V/21 Basket
Dear Mr. Roberts:
The material specification for borated stainless steel (radionox A18) submitted by.
GNSI as part of their safety analysis report Indicates limits of 1.0310.05% for the boron. The minimum for unqualified acceptance is 0.98%. According to the BAM letter to the NRC dated August 20,1987, samples of this material numbering from B28 to B39 show values varying from 0.91 to 0.95% which is below that required for unqualified acceptance.
A review of the strengths or samples taken from the deviant material indicates that the lowest yield strength obtained (303 MPa,43.9 ksi) is still about 20% higher than the minimum yield strength (248 MPa,36 ksi) used to establish the design stress intensity limits. Consequently, the boron content of the deviant material does not adversely affect the structuralintegrity of the cask.
In reviewing the criticality analysis for the Castor V/21 cask, we find that_ the actual weight percent boron used was 0.9136 which, within two significant figures, is equivalent to the minimum boron content of the deVQnt' materials.
There is some additional conservatism in the criticality calculations arising from the use of B-10/B-11 weight percentages of 18.30253/81.69747 rather than the;gt material does not adversely handbook weight percentages of 19.5/80.5. Consequently, the boron content of the devi
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affect the criticality margins.
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For the above reasons, we conclude that he deviant material may be used for Castor V/21 baskets without compromising safety.'
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8710130353 870917 Very truly yours, PDR ADOCK 07100510
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