ML20035F537

Staff Requirements Memo Advising That No Objections Raised to Signing Final Rule on Secy 93-076, Final Rule:List of Approved Spent Fuel Storage Casks:Additions

ML20035F537
Person / Time
Issue date:	04/01/1993
From:	Chilk S NRC OFFICE OF THE SECRETARY (SECY)
To:	Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
References
REF-10CFR9.7 NUDOCS 9304220009
Download: ML20035F537 (4)

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NUCLEAR R U A OR COMMISSIOP' 9b

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WASHINGTON. D.C. 20555

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OFFICE OF THE SECRET AR Y i

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MEMORANDUM FOR:

James M. Taylor Executive Director for O ations FROM:

Samuel J. Chilk, Secreta

SUBJECT:

SECY-93-076 - FINAL RULI::

i" LIST OF APPROVED SPENT FUEL STORAGE CASKd:

ADDITIONS" This is to advise you that the.Com:aission has'not-objected to-the i

staff plan to sign'the final rule on additions to the list of approved spent-fuel storage casks and forward it for publication in the Federal Reaister with the change indicated in the attachment.

Attachment:

As stated cc:

The Chairman Commissioner Rogers Commissioner Curtiss Commissioner Remick Commissioner de Plangue OGC OIG Office Directors, Regions, ACRS, ACNW (via E-Mail)

OP, SDBU/CR, ASLBP (via FAX) l l

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SECY NOTE:

.THIS SRM AND SECY-93-076 WILL BE MADE PUBLICLY AVAILABLE 10 WORKING DAYS FROM THE DATE OF THIS SRM i

930401 07f PT9 7

Section 1.2.5. " Maximum MSB Removable Surface Contamination" contains specifications for limiting the amount of radioactive contamination permitted on the external surface of the MSB. These specifications are conservative, and are based, in part, on equivalent criteria used for the safe

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transportation of radioactive material [see 10 CFR 71.87(1)]. Hence, compliance with them will ensure that off-site dose limits of the NRC's regulations will be met for normal and off-normal conditions alike. The general licensee must also use the cask in accordance with the reactor operating license and the Certificate of Compliance. The general licensee is also responsible for complying with other Commission regulations regarding radioactivity release limits. Therefore, potential releases from the MSB when combined with routine releases from the reactor should not exceed dose limits i

at the site boundary.

12. Coment. Commenters indicated that casks placed close to the shore of Lake Michigan represent a serious threat to the environment, especially to the Great Lakes which have 20 percent of the world's surface fresh water.

Response. A utility's use of the VSC-24, for the storage of spent fuel in casks at a reactor site, would not have a significant impact on the environment. This finding is supported by the NRC safety and environmental evaluations for the VSC-24 cask, including the applicant's demonstration of compliance of the cask with NRC requirements, as well as by the 1990 rulemaking on dry cask storage and the 1984 and 1989 waste confidence proceedings. Since the '!SC-24 can caly be used by c licen cc provided the 4 rite par:=ters :re crveloped by the c::k design b :i,

Specified in the-4 SAR and SER, cc:k :terage of : pent fuel ne:r the shore of Lake Michigan within e

' ~LMect 20

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'o the specified par =0ter: would not have

ignificant impact on the e envirement.-o

13. Coment. Some comenters expressed concern that extremes in temperatures and humidity would cause dry casks to leak.

Resoonse. The VSC-24 cask design was analyzed for possible effects of extremes in temperature and humidity. These analyses showed no leakage will occur as a result of temperature or humidity extremes.

The thermal i

analysir presented in the SAR and the NRC evaluation documented in Section 4.0 of the SER considered temperature extremes for both hot and cold conditions.

Based on this analysis, the NRC concludes no breach of the MSB confinement barrier or leakage from the MSB will occur.

14. Coment. Some comenters speculated that a catastrophic release of radiation maw occur from a possible explosion caused by spontaneously i

flamable uranium hydride in the presence of oxygen.

It is postulated that the temperature inside the cask will be hot enough to rupture fuel rods which will, in turn, cause the presence of hydrogen to create uranium hydride.

Resoonse. The NRC does not believe that an explosion inside a storage cask caused by flamable uranium Sydride in the presence of oxygen is 4

credible for the following reasons. Oxygen gas is not expected to be present because all casks are designed to have an inert atmosphere.

Further, the formation of uranium hydride is not credible due to the lack of a significant source of hydrogen. Finally, all casks are designed so that the internal temperature will not cause the fuel rods to rupture.

Therefore, the conditions nece tsary for this scenario to occur would not exist.

15. Comment. The SER states that there is to credible chain of events that could spread contamination from the MSB. Only air-coolant loss due to 21

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I Proposed Revision to Response to Comment 12 on page 20 of FRN (if needed)

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Delete last sentence a - insert the following:

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While the VSC-24 cask-is being approved for use under a general license,. it can only be used by a licensee provided the reactor site parameters (e.g.

average ambient temperature, seismic accelerations, flood water velocity, j

fires and explosions, etc.), are enveloped by the cask design basis, as t

specified in the SAR and SER.

Proper use of a certified storage cask at any i

site (whether near Lake Michigan, a river, a' bay, or an ocean) with site j

parameters that are bounded by the cask design, would not have a significant impact on the environment..

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