ML20235K681

Application for Amend to License R-37,reducing Possession Limit for U-235 to 29 Kg

ML20235K681
Person / Time
Site:	MIT Nuclear Research Reactor
Issue date:	09/25/1975
From:	Lisa Clark MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20235K610	List: ML20235K607 ML20235K641 ML20235K649 ML20235K678 ML20235K681 ML20235K689 ML20235K700 ML20235K703
References
NUDOCS 8902270204
Download: ML20235K681 (2)

Text

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-L (V lifilif fil 11 littlif !!!!!!!!Ill September 25, 1975 Docket No. 50-20 U.S. Nuclear Regulatory ,ommission Division of Reactor Licensing

-Attn.: Mr. George Lear, Chief Operating Reactors Branch #3 Washington, D.C. 20555

Subject:

Shh Possession Limit, License R-37 Gentlemen:

In response to Nuclear Regulatory Commission, Division of Reactor Licensing letter of August 29, 1975, Massachusetts Institute of Technology hereby submits an application to amend its Facility Operating License

[_T No. R-37.

V.

The requested amendment consists of reducing the possession limit for uranium-235 authorized in paragraph 2B(2) of the license from 45 kilograms to 29 kilograms.

The U-235 possessed and used under License R in the form of fuel elements and falls into three categories:

a) Unirradiated fuel b) Partially burned fuel c) Spent fuel.

The unirradiated fuel is purchased periodically. Because we have made only one purchase of this type of fuel in the past and because it will be necessary co find a new f abricator for future procurement, we do not have  ;

significant e::perience on which to evaluate the effect of purchase quantity on '

cost. It has been our expectation that a two-year suppiv ,7 fuel elements) would be about the minimum econcaic quantity to fabrica a one batch. At 0.445 kg U-235 per element this amounts to 12 kg. U-235.

In order to remain below the " threshold" quantity defined by paragraph 73.l(b) of 10 CFR 73, it will be necessary for us to take delivery of only the numoer of elements needed fo: refuelling, plus a few more standby elements which would be n ored in an :.:ceptacle vault at the MITR. The unirradiated O

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i, ,) U.S. Nuclear Regulatory Commission September 25, 1975 Page 2 fuel stored in the vault together with other special nuclear material at the site would be kept below the " threshold" quantity. The remaining newly-purchased elements would be stored elsewhere, as is now being done with some of the elements from our last purchase.

A core loading for the reactor is normally 26 elements. In order to achieve maximum authorized burnup, a fuel management program has been developed, which calls for cycling some of the elments from the reactor to storage in the reactor pool and then back into the reactor before being discharged as spent fuel. The amount of partially burned fuel being stored for re-use varies from year to year, but it nevet exceeds 25 atandard elements plus a few special elements used for reactor physics and other tests.

Spent fuel will be discharged to a storage tank, probably in batches of 15 elements. It has been our practice in the past, for reasons of economy, to accumulate enough fuel (i.e. 56 elements) so that we could make two consecutive shipments of 28 elements each. However, the savings over making periodic single shipments were not great, and so the above amended possession limit of 29 Kg U-235 is based on the single shipment schedule. It also assumes 25% burnup in the spent fuel. When the steady state condition has been reached for the f- s

(' ) MITR-II, spent fuel shipments will be made about every second year, assuming 28 elements per load.

Because we have recently shipped all of the spent fuel from operation of the MITR-I and have on-site only 32 elements for startup of the MITR-II, our current inventory under License R-37 is only 15.1 Kg U-235. This includes 0.8 Kg U-235 in excess, unirradiated, special fuel elements for the MITR-I, which we hope to dispose of shortly. The MITR-II inventory will increase 4 Kg l or 5 Kg each year until it reaches 27 Kg in 1978. The schedule calls for 29 Kg in 1980 and then a peak of 35 Kg in 1981, followed by varying but lesser amounts thereafter.

In recponce to your letter, we are requesting a possession limit of 29 Kg U-235 at this time, since it is clear that our inventory must increase after the reactor gets back into operation. We will than re-evaluate our requirements on the basis of operating experience and subsequently request an increase above i 29 Kg if necessary. 1 Sincerely yours, kfc '

Lincoln Clark, .

Director LC/ce

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