ML20204A125
| ML20204A125 | |
| Person / Time | |
|---|---|
| Issue date: | 04/30/1986 |
| From: | Rouse L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Barnhart V GENERAL NUCLEAR SYSTEMS, INC. |
| References | |
| REF-PROJ-M-37 NUDOCS 8605090376 | |
| Download: ML20204A125 (4) | |
Text
_
APR 3 01995 Project M-37 General Nuclear Systems, Inc.
ATTN:
Mr. Victor J. Barnhart Vice President 135 Darling Drive Avon, CT 06001
Dear Mr. Barnhart:
SUBJECT:
ACCEPTANCE AS A REFERENCE OF " TOPICAL SAFETY ANALYSIS REPORT FOR THE CASTOR V/21 CASK INDEPENDENT SPENT FUEL STORAGE INSTALLATION (DRY STORAGE)," REVISION 1, WITH ALTERNATIVE FUEL BASKET DESIGN In September 1985, the Nuclear Regulatory Commission (NRC) staff completed its review of Revision 1 of the General Nuclear Systems, Inc., " Topical Safety Analysis Report for the CASTOR V/21 Cask Independent Spent Fuel Storage Installation (Dry Storage)" (TSAR). Based on this review, NRC staff concluded that the CASTOR V/21 cask design as described in the TSAR provides for an acceptable means to meet the requirements of 10 CFR Part 72, as defined in our letter to you of September 30, 1985, and subject to appropriate specifications expressed in the enclosures of that letter, (Enclosure 1, Limitations and Operating Conditions, and Enclosure 2, the NRC staff's Safety Evaluation Report).
This acceptability was limited to conditions and the spent fuel detailed in the TSAR (i.e., Revision 1), augmented by information submitted after the filing of Revision 1 and September 30, 1985, letter with its enclosures.
Subsequently, NRC staff was officially informed by a General Nuclear Systems, Inc., (GNSI) letter dated October 10, 1985, of an occurrence involving detection of weld area cracks in the borated stainless steel fuel basket of the CASTOR V/21 cask being used in an unlicensed Department of Energy research and development storage demonstration at the Idaho National Engineering Laboratory.
Our letter to you, dated October 14, 1985, requested from GNSI an analysis and evaluation of the cause(s) of the basket cracks and an assessment of the need for design changes.
Since October 1985, we have received further information from GNSI and not with GNSI staff regarding the reported basket cracks. Questions regarding the basket design and materials remain to be fully resolved. While continuing its tests and analyses of the original basket design, GNSI submitted by letter dated February 28, 1986, an alternative design for a cask fuel basket which does not employ borated stainless steel as a basket material.
NRC staff has reviewed this alternative basket design, as subsequently revised in your letters dated March 25, 1986, and April 23, 1986. Our analyses of the CASTOR V/21 all stainless steel basket indicate the-following:
I 8605090376 860430 PDR ADOCK 05000280 Y
l APR 3 n gg Mr. Victor J. Barnhart 2
1.
For spent fuel of an initial enrichment of 5 2.2 weight percent U-235, k,ff is found to be 5 0.95, which is an acceptable value for meeting the suberiticality requirements of 10 CFR Section 72.73. 0ur conclusion is based on independent staff analysis using the KEN 0 V program.
The applicant's analysis also results in a k 5 95.
gff 2.
The staff has also performed independent structural analyses for the fuel basket design, which, as noted above, has been revised from that originally presented and analyzed in the TSAR (i.e., there have been changes in addition to excluding the use of borated stainless steel as a basket material). Our analyses indicate the following:
a.
An elastic analysis of the basket for thermal stresses shows all stresses to be within acceptable limits for unborated stainless steel.
b.
A dynamic elastic analysis based upon a 150 g load shows that the basket will maintain fuel assembly criticality safety provided the 20 mm plates at the corner junctions are connected by full length, full penetration welds. This method of construction is preferred over the alternative featuring the bolted construction.
Furthermore, the analysis shows that the 5 mm gusset plates will buckle at about 110 g's.
Consequently, gusset thicknesses should be increased to 10 mm thick.
o The changes in item 2.b above and oither changes to the drawing relating to the deletion of items 37, 38, and 39, the flux trap spacer dimensions, and deletion of the reference to RADION0X material, as indicated in the GNSI letter of April 23, 1986, should be reflected in the corrected TSAR. With the changes discussed above, the all stainless steel fuel basket design, when used with the CASTOR V/21 cask design, meets the structural requirements for normal, off-normal and accident conditions as required under 10 CFR Section 72.72.
Based on the staff's previous review and analyses, as documented in the September 30, 1985 letter of approval with enclosed Safety Evaluation Report and the staff's supplemental review and analyses for an all stainless steel basket design discussed above, the staff concludes that, with the revisions stated in the GNSI letter dated April 23, 1986, the all stainless steel basket design submitted by GNSI in its March 25, 1986 letter meets the requirements of 10 CFR Part 72.
Further, with this basket design the CASTOR V/21 nodular cast iron cask design, as documented in the TSAR and approved in our letter of September 30, 1985, acceptably meets the requirements of 10 CFR Part 72, provided that initial fuel enrichment is restricted to 5 2.2 weight percent U-235 for spent fuel to be stored in the cask.
It is requested that General Nuclear Systems, Inc. publish an approved version of this report, with proprietary information in a separate binder, as per Item 3,
" Proprietary Information," of the Introduction to Regulatory Guide 3.48, and submit 25 cop 4>, for docketing upon resolution of questions regarding its borated stainlus steel basket design and a-finding by NRC staff of design acceptability.
t
s APR 3 91986 Mr. Victor J. Barnhart 3
In the approved version, there are items relating to the CASTOR V/21 Topical Safety Analysis Report, Revision 1, which need to be clarified or corrected (see our September 30, 1985 letter to you, enclosure 3, TSAR Corrections).
While they do not affect our assessment of safety and compliance with the requirements of 10 CFR Part 72 as reflected by the SER, they should be incorporated in the TSAR.
This revision is also to incorporate this letter, following the title page and a listing identifying with submittal dates, supporting supplemental information submitted after the TSAR, i.e., Revision I and docketed under Project M-37.
Ther[ ape +
Manificathn-of_the-approved report is to have an "A"
suffix.
a t ggi; g.,7,
,a TheNRCstaffdoesnbr~TnYendtorepeatthereRewofthefeaturesimportant to safety described in the TSAR and found ace g table, when it appears as a reference in a licensFTpylication except to assure that the material
~
presented is applica31e to the application invetved.
The NRC staff's acceptance applies o W t6 the features descri ~gi in the TSAR, as augmented by the supplemental in rmation submitted subseq 1 to the filing of the TSAR (i.e., Revision 1). 14cluded--in -this supplemeMhl information is the declassifiedBAMreportpreviouslysubmittedasrpoprietaryAppendix12of
's Revision 0oftheTSAR.
with Should NRC criteria' acceptability of the{or regulations change, sutbJhat our conclusions as to the report-are-invalidated, Geheral Nuclear Systems Inc.,
and/or the applicant;s referencing the Topical; Report will be expected to revise and resubmit !their respective documentation, or submit justification for the continued ef;fective applicability of th6 Topical Report without revision of their re,spective documentation.
JGray t
' - ~ ~ ~
Sincerely, TChen, ORB I DISTRIBUTION:
Please return original JKennedy concurrence copy to FBrown SS 396 original sicaed ty LA File
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