ML20136H967

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Requests Program Plan Outlining Steps to Maintain Same Level of Pressure on Us Licensees as NRC Intends to Maintain on Foreign Users of Us Fuel,Per Highly Enriched U Policy Paper Recently Published by Commission
ML20136H967
Person / Time
Issue date: 08/27/1982
From: Ahearne J
NRC COMMISSION (OCM)
To:
NRC OFFICE OF POLICY EVALUATIONS (OPE)
Shared Package
ML20136H905 List:
References
FOIA-85-379 NUDOCS 8508200566
Download: ML20136H967 (1)


Text

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  • */ f UNITED STATES NUCLEAR REGULATORY COMMISSION L/

k CASHIN GTEN, C.C. 20S55 y

p# August 27, 1982 .

CFFICE OF THE COMMISS10NEpl MEMORMiDUM FOR: Acting Directo , O E FROM: John Ahearne

SUBJECT:

HEU POLICY The Cormission has recently, published an HEU policy paper.

In it the Cormission commits to taking steps to get U.S.

licensees to move to lower enrichment fuel. ' Commissioner

~

Roberts correctly noted iio iuch steps have been identified.

Please prepare a program plan outlining appropriate steps, to maintain the same level of pressure on U.S. licensees as ,

the Commission obviously intends to maintain on foreign users of U.S. fuel. .

I would appreciate a draft proposal by September 30.

cc. Chairman Palladino Cormissioner Gilinsky

[ Commissioner Roberts '

Coraissioner Asselstine .

EDO

. OGC 8508200566 850727 PDR FOIA AFTERGOB5-379 PDR

ATTACHMENT 3

/ #g UNITED STATES l/ NUCLEAR REGULATORY COMMISSION -

March 1, 1983 MEMORANDUM FOR: Comi er Ahearne FROM: nn Zer

SUBJECT:

POLICY TO REDUCE ENRICHMENT AT DOMESTIC RESEARCH AND TEST REACTORS Attached is a brief paper prepared at your request. It proposes several options for encouraging domestic research and test reactors to use low enriched uranium fuel. The NRC licensing staff has had several opportunities to review this paper. The various options have also been discussed in general terms with the National Organization of Test, Research and Training Reactors whose representatives met with the staff and OPE earlier this month.

In addition, the paper has been informally reviewed by the Departments of State and Energy.

I rocc=end that the Cormission pursue two of the options that have been '

proposed:

( (1) that no new research reactors be licensed for use of HEU fuel unless the applicant shows that the unique purpose of the project could not be achieved without using HEU fuel.

(2) that existing reactors must replace burned up HEU fuel with LEU if technically feasible with existing fuel technology at the time of refueling. -

Sheuld the Comission wish to pursue these options OPE is ready to work with the staff to see that the policies are put into place.

Attachment:

As Stated cc: Chairman Palladino Co =issioner Gilinsky Cc =issioner Roberts Comissioner Asselstine Herzel Plaine Samuel J. Chilk William J. Dircks .

C0': TACT:

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  • POLICY TO REDUCE ENRICHMENT AT RESEARCH AND TEST REACTORS

- For some time there has been concern about the proliferation risks associated with inventories of highly enriched uranium used in research and test reactors abroad. In August,1982, the Commission issued a policy statement expressing its concern and indicating support for the conversion of foreign reactors to low enriched uranium. In conjunction with the issuance of this policy statement Comissioner Ahearne noted that the Comission had committed i itself to get U.S. licensees to move to lower enrichment fuel and requested that the Office of Policy Evaluation develop a program plan outlining appropriate steps to maintain the same level of pressure on U.S. licensees as the Comission intends to maintain on foreign users of U.S. fuel. This paper

.J su marizes the current situation in the United States and suggests some policy options which the Comission may wish to pursue in order to achieve this objective.

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Current Situation

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In its annual report U to the Congress, the Department of State sumarized the current situation with respect to highly enriched uranium as follows:

The United States is the principal exporter of highly enriched uranium for use as fuel in research and test reactors. Forty-seven such reactors abroad, with powers of 1 MW or more, currently use HEU of United States origin, as do 22 reactors2 / of that type and size in the United States.

Exports of HEU for use in the foreign reactors average about 600 kilograms enr.ually; about 500 kilograms are used domestically. Since UReport to the Congress pursuant to Section 601 of the Nuclear Non-Proliferation Act of 1978.

2/ Includes DOE reactors not licensed by NRC.

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2 the duration of the fuel cycles, from the export or domestic delivery of fresh HEU to the return of spent fuel, averages about four years, approximately 4,400 kilograms of HEU of United States origin are in circulation at any given time, for research reactor use alone, in the United States and abroad.

l There are 28 NRC-licensed research and test reactor facilities of all sizes.

mostly university operated, which presently may use highly enriched uranium

[HEU). Only 16 of these facilities are currently authorized to possess a formula quantity of HEU. Of these 16, seven are 1 MW or less, and nine are greater than 1 MW. The total capacity of NRC-licensed research and test reactor facilities using HEU is approximately 50 MW. In addition to these

. facilities there are 15 Department of Energy resear h and test reactors totalling some 450 MW and 1 U. S. power reactor (Ft. St. Vrain) which also utilize HEU. Table 1 and 2 attached indicate the location of each research I and test reactor licensed by NRC which may use HEU and show the authorized level of fuel which the licensee may possess.

Because the high cost of construction and operation and relatively low student enrollment in the nuclear departments of universities, the staff does not expect to receive any new license applications for research reactors in the near future. Following the issuance of the present backlog of 20 license

renewal applications, there will be 1 to 4 renewals processed annually with
renewals issued typically for 20 years.3/ Most of the research reactors are not refueled often due to low usage and consequently low burn-up. At these current rates r.any licensees expect to use their present cores for the rest of this century. ,

3/ The licensing backlog includes research and test reactors which use either

  • LEU or HEU. There are 66 NRC-licensed research and test reactors.

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3

. Conversion to Low Enriched Uranium Fuels In 1978 the United States government established the Reduced Enrichment for Research and Test Reactors (RERTF) program. The RERTR program is administered by the Department of Energy (DOE), with the bulk of the technical responsibility centered at the Argonne National Laboratory (ANL).

The goal of this program is to substantially minimize the trade in HEU (HEU, containing greater than 20s U-235) by developing and demonstrating new high uranium density fuels to permit reactor conversions to the use of low

> enriched uranium (LEU, containing less than 20% U-235).

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In assessing the practical feasibility of utilizing low enriched uranium fuel in existing research reactors, the DOE RERTR Program is using the following criteria: safety margins and fuel reliability should not be lower than for the current design based on highly enriched uranium; major reactor modifications shculd not be required; and the loss in overall reactor

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performance (i. e., flux per unit of power) as well as the' increase in operation costs should be minimized.

Enrichment reduction by simple substitution of lower enriched uranium in existing fuel designs has the immediate effect of reducing core performance and cannot meet the above criteria. Enrichment reductions can be feasible for nost research and test reactor designs if the U-235 centent in the fuel element is increased while the enrichment is decreased. Irradiation

! performance, in terms of flux per unit of power, can remain comparable to that attaired with HEU fuel. The neutron poisoning effect of the U-238 contained in LEU-fuel must be compensated to maintain reactivity, fuel life ,

and reactor performance.

For plate-type fuel the necessary increase in uranium content per fuel i element could be achieved by increasing the volume fraction of the fuel meat

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4 and/or by increasing the uranium concentration in the fuel meat. Increasing the volume fraction of the fuel meat can be accomplished by decreasing the plate clad thickness and increasing the meat thickness or by using a smaller number of thicker plates per element. Either route must avoid any unnecessar.wdecrease in coolant volume. Each approach has limitations which make it difficult to adequately increase the fuel meat volume fraction in high-performance reactors that operate very close to their thermal-hydraulic limit with their present HEU fuel. -

If the uranium concentration in the fuel meat could be adequately increased without changing the thickness, it would have negligible effects on the thermal-hydraulics properties of the core. The implementation of this

, approach is tied tc the development and demonstratic. of fuel materials offering significantly higher uranium density using advanced fuel fabrication technology. Development of new fuel material, appropriate fabrication

( techniques and irradiation testing of the fuel is currently underway in the U. S. under the auspices of the RERTR program and in complementary programs of various foreign countries.

-The Departcent of Energy program to achieve this goal is a two-phased fuel developtent, testing and decenstration effort. Phase I involves production and testing of aluminide- and oxide-dispersien LEU-fuels with naximum achievable uranium densities, using best available com.ercial technology for fuel fabrication. These " current technology" LEU-fuels are limited in service to the lower power reactor applications, such as the on-going fuel core demonstration of LEU fuel in the 2%' Ford Nuclear Research Reactor at the University of Michigan.

To date. Phase !! activities have included: selection of uranium silicide as a candidate material capable of providing significant increase in uranium ,

I density for the fuel meat; production and extensive irradiation 9f miniplates

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w_ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . . _ . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ . . _ _ _ _ _ _ . _ _ _ - _ _ _ _ . - _ _ _ _ _ _ _ . _ _ _ . _ _ _ . _ _ _ _ _ _ . . _ . _ . _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ . _ _ _ _ _ . _ _ _

- 5 n (clad fuel specimens) of silicide-dispersion fuel materials; production and initiation of testing of full size prototype fuel assemblies in selected test

. reactors; and initiation of post irradiation examinations of miniplates irradiated to as high as 801 burnup of fissile content.

Future phase II activities include: completion of post irradiation examinations on most of the irradiated LEU-fuel miniplates (and any other specimens which might be deemed necessary); and selection of the preferred uranium silicide dispersion material for fabrication into LEU-fuel for a full j core demonstration in a high performance reactor such as the Oak Ridge i Research Reactor. Such a commercial procurement and irradiation performance

demonstration is planned during the period FYs 1985-88. At this time, the RERTR program has completed too few post irradiation evaluations to quantitatively assess the performance of the highest U-density silicide fuel candidates.

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NRC must review the irradiation performance data generated in the LEU-fuel

. test programs of DOE and its partners abroad, as a basis for establishing licensibility of the resulting LEU-fuels. Appropriate safety analysis reports must be completed for each specific reactor application before LEU replacetent cores could be licensed for use in the related research and test reactors. If approved, a license amendment could be issued for the specific LEU-fuel application in accordance with normal licensing procedures.

Policy Options The following discussion assumes that a principal concern of U.S. policy with respect to HEU use ebroad is the threat of national diversion. Thus, the goal of U.'S, policy is to stop all international traffic of HEU and the purpcse of this paper is to discuss domestic policy options which comport .

with this objective. To further this goal, it is important that the U.S.

6 have a domestic policy on HEU reduction comparable to its overseas policy.

Otherwise, it has been argued, foreign operators will be relucte.t to convert to the use of LEU and could claim the U.S. was trying to gain an advantage in nuclear technology and research.

There are a number of steps which the NRC could take to help achieve this U.S. ncn-proliferation policy objective. There are also a number of other steps which could be taken by other agencies to encourage conversion of non-pcwer reactors to LEU. These are all discussed below with an indication as to who might be affected and how the policy might be implemented. In the discussion below it is assumed that current U.S. physical protection

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regulatiod are suffic'iint to counter domestic lhreats anii Uat'the primary

.purposeoftheinitiativeistoencourageconvers'ionoffo'reignlac~iTtiIs.

_ Option 1: No new research reactors would be licensed for the use of HEU fuel unless the applicant showed that the unique purpose of the project could not

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be achieved without using HEU-fuel.

The Ccrmission could issue a policy staterient which would state that the NRC would no longer censider applications for a construction permit to build ,

non-pewer facilities utilizing HEU unless the applicant could show that the

. objective of the project could not be met using LEU fuel. This probably will not affect any one immediately since the staff does not believe therc are any such applications contemplated at present. It would send a message to users of HEU that the U.S. is taking steps to limit the use cf HEU. This option has been formulated to require justification for HEU fuel use to take into account comments received during a recent meeting held by the staff and the Office of Policy Evaluation with the National Organization of Test, Research and Training Reactors. This group felt that a policy of absolute prohibition of new research reactors using HEU could be damaging to U.S. research in ,

reactor and fuel technology. In addition, the State Department has informed

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.' 7 us after an informal review of this paper that in its formulation of the RERTR program, the U.S. has reserved the right to build new domestic research reactors using HEU, if the mission justifies it. Apparently, france, the USSR, and the U.K. maintain the same option.

Option 2: Existing reactors must replace burned up HEU fuel with LEU, if technically feasible with existing fuel technology at the time of refueling.

The Coraission could issue a rule prohibiting those research reactors which could use LEU from refueling with HEU unless licensees demonstrated that it would not be technically feasible to use LEU fuel in the reactor or, alternatively, thtt the appropriate LEU fuel was unavailable from fuel fabricators. The basis for the prohibition would be that it is in accord with U.S. policy with respect to exports of HEU to non-power reactors abroad.

The consequences of,such an approach is far reaching but gradual. There are

( twenty-eight research and test reactors potentially convertible to low enriched uranium fuel. This would immediately affect all five TRIGA-type reactors as well as three plate-type reactors (University of Michigan, Rhode Island NSC, University of Lowell [ Mass.]). As matters now stand, General Atomics is the sole source fuel fabricator for TRIGA reactors and it no longer fabricates HEU fuel for these reactors. Only LEU fuel is available, so TRIGA users no longer have any choice but to replace their HEU elements

. gradually with LEU as their current fuel is burned up. Licensing is not a problem since the technical specifications for these facilities already permit cperation using LEU. k'hile these users have no choice but to convert, due to their low utilization rates it may take a long time.

The situation with respect to the 3 plate-type reactors is that a full-core LEU de6cnstration is on-going at the University of Michigan reactor using 1.7 gm/cc density fuel. Although incomplete, this test shows promise for .

complete success. The Rhode Island NSC and University of Lowell reactors

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could convert to similar LEU fuel as their current HEU fuel is burned up, I assuming no safety problems arise in the course of NRC's licensing reviews.

The on-going full core demonstration has indicated that mixed HEU-LEU cores are both technically and economically feasible for such reactor applications.

I l If adopted, a rule prohibiting research reactors from being refueled with HEU if capable of using LEU would result in a gradual reduction in the HEU content of the cores of research reactors. Table I and II summarize the current fuel conversion situation with respect to research and test reactors for sizes greater than and less than one MW respectively. Most reactors it appears must await the successful development of silicide fuels which are not expected to be available until the late 1980's. For reactors less than one MW, based on current usage rates, existing cores will probably never have to be replaced during the life of the reactor. Consequently, this option would .

not affect many small reactors which are owned by universities.

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Option 3: I m.ediate replacement of the cores of those existing reactors

- capable of using LEU.

Under Option 2, the process of conversion of those reactors where conversion is feasib1e would be gradual due to the low rates of burn-up. An alternative to this approach weuld need a more radical change in federal policy and in the availability of federal funds. If the Commission believes that it is inportant to achieve dcmestic conversions more rapidly than in the previous alternative, then additional steps need to be taken to assist in the cerversion of fuel inventories or face the prospect that these reactors would be shut denn because operators could not comply due to lack of funds. ,

A more' radical approach than the policy proposed in Option 2 would be for the Commission to push for ix.ediate conversion of fuel inventories to LEU only. .

Of those reactors greater than 1 MW, this would affect five TRIGA reactors

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l - immediately and two plate-type reactors (Rhode Island and Lowell), given the successful use of LEU fuel at the IJniversity of Michigan reactor. Michigan already has a complete LEU core. The other potentially convertible reactors

) , must await the successful development of silicide fuels. Based on the

! current RERTR schedule, high density silicide fuel will not be available for a full core demonstration for another three to five years.

l As for the fourteen reactors which are less than 1 MW in size, according to l

l analyses done by Argonne National Laboratory, there are four which could be converted to oxide fuel and two to aluminide fuels with current technology (see Table II). Shculd the Commission decide to pursue this option, consideration should be given to excluding reactors possessing less than a

. formula quentity of stratagic special nuclear from the requirement to im ediately replace their existing fuel inventories. This would mean fewer funds would be needed to effect the necessary inventory exchange. While this

( appr'oech may be practical from a domestic point of view, the State Department has indicated that this is not their approach with respect to' exports of HEU to foreign reactors. They would like to see all commerce in HEU stop.

If the Cemission believes that it is important to achieve complete fuel inventory conversion more rapidly than in previous alternatives, then ,

additicnal steps need to be taken to assist in that conversion. The Departr ent of Energy, the Office of Management and Budget, and appropriate Congressicnal Comittees would have to be ccnvinced to provide funds at least to assist in the conversion, and to procure the fabricated fuel cores. It.>

should be noted that current U.S. policy does nct propose immediate conversion of facilities using U.S.-supplied HEU abroad. Given the state of university finances and present enrollments in nuclear departments, immediate conversion without financial support from the government could well result in closing of these facilities. Should government funding not be available to .

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10 private industry for complete conversion, it is unclear what action they would take.

At present all university-owned reactors receive their fuel from the Department of Energy through the University Reactor fuel Assistance Program (URFA). The fuel is D.O.E. owned. The transportation costs to the reactor is an important factor in the cost of the fuel, and URFA does not necessarily pay for it. DOE presently absorbs the cost of reprocessing this fuel, but

' not out of the URFA budget which totalled $1.6 million in FY 82.

The cost of a new core is difficult to estimate since fabrication costs are a function of the technology, basic fuel costs, and throughput of the

. fabrication facility. However, for order of magnitude purposes, a fabrication cost of $25,000 per fuel element can be assumed. Since a typical (1 MW) research react - has about 30 elements, it implies that it would cost about 5750,000 for fuel to immediately replace an existing core. Added to

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this must be facility modifications (if any), shipping, storage and reprocessino costs. Costs for a complete conversion are estimated to range from $1 to S1.5 million per reactor core. As a percent of the URFA budget,

.the cost of conversion would be large. As a percent of the DOE budget, the cost would be miniscule.

Option 4: Conversion of DOE facilities utilizing HEU to LEU.

As pointed out earlier, the total capacity of DOE facilities using HEU exceeds that licensed by fiRC by about a factor of 9. Because of a greater degree of reactor utilization by DOE as compared with NRC-licensed research and test reactors, the replacement of HEU reactor fuel with LEU fuel as it is burned'up'may be more rapidly implemented. On this point it should be noted that of the 450 MW operated by DOE, five reactors represent the bulk (440 MW) .

of the capacity. One of these reactors has a capacity of 250 MW and is

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. currently being used for defense-related research. Moreover, at least three of these reactors totalling 410 MW could not be converted at present because f 1

they require successful development of silicide fuels. Therefore, while it

( is possible that DOE facilities could be used for demonstrating the country's resolve to convert its facilities to LEU in support of international policies on non-proliferation, it does not appear that a significant portion of the capacity operateo by DOE could be rapidly converted given the nature of the facilities.

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TAul[ l POTfNTIALLY CONVfilllDLE .

DOMESTIC k[$[ ARCH AND T[$I REACTORS GREATER TilAN I HW PRf5ENTLY USING ll[U GREAllR lHAN 10%

Reactor Location Power Au t ti . Annual Hinimon LIU Density Lic. Comenent MW fuel U-235 'No 6euen. Gein*Jtry Exp.

Kg. Reymnt. Change Change Date TRIGA Type Reactors:

I 1.3 2002 General Atomics no loneser

1. Oregon State University I 0.07 -
2. Wdshington State Univ. I lie.3f 19.9 g

0.04 1.3 - 2002 munufactures ll[U fuel, but 13.7 37 0.11 1.3 - 2000 they do manufacture 1[H fuel.

3. Univ. of Wisconsin 1 2002 l

These reactne s currently have

4. Texas A & M 1 17.2 0.10 1.3 -

1.5 35.0 0.02 1.3 -

2000 s nimed itEU-LEU cores.

5. General Atomics (La Jolla)

Plate-type Reactors:

45.0 12.9 5.6 7 2003IIMay be convertible using

1. Nat'l Bureau of Standards 10 silicide fuels 45.0 10.7 5.6 7 2001 Jt- 2. University of Missouri 10 37 40.0 5.4 3.7 3.1 2003 Must await st11 Cide fuel 3.UnionCarbide(NewYork) 5 '

development.

W 4. M.I.T. Research Reactor 5 29.0 5.4 8.7 7 1996 13.5 1.9 3.4 7 1994

5. Georgia Tech Research Reactor 5 ,

A A, 6. Ford Nuclear Reactor 19115 rull-core LEU demo on-going2 /

(Univ of Michigan) 2 16.1 3.3 - 1.7 10.4 2.5 3.9 1.7 200;' Poss, conv. af ter U. Mich d.wo.

7. Rhode Island NSC - 2 1.3 3.3 3.1 2002 Must await med, dens exide fuel dev.
8. Univ. of Virginia Reactor 2 17.6
9. University of Lowell (Mass.) 1 4.8 0.2 3.4 1.7 1985 Poss conv. after U. Mich. dimo.

' h Relicense applications pending. Renewal projected to be approved for date shown.

low density oxide fuel d or p eiu k ck

  • Not fe u M e w en m.th aamceA tea,no eyes now smate ace toe.w.

s w m wa_ 4 % ,u<m m ysc.a w aoy conoemic,y % LEM 1noc \u 3 c_o w Anble moJi6t. dom to % reac k"

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POTENTIALLY CONVERllDLE DOMESTIC I:[SEARCll AND IIST REACTORS LESS lilAN 1 MW PRES [NTLY USING ltLU GHEATER THAN 701 Reactor Location Power Auth. [sp. Coeuent MW luel Date Kg.

Il

1. Virginia Polytechnic Instit. 0.1 8.0 ?00? Could convert to oxide fuel
2. University of Missouri (Rolla) 0.2 4.J 200J 3/ St.itus Unknown
3. UCLA 0.1 4.9 2003 3/ Could convert to ontde fueI II y {*>@ 4. Manahattan College 0.0001 3.? 1984 Status unknown 37 Al prox. annual burnup 21.77
5. University of Kansas 0.75 4.0 700.1 3f
6. Iowa State University 0.01 4'.6 7003 Apprus, annual burnup 21.2/
7. Worcester Polytechnic Instit. 0.01 4.0 7002 II 44

,p 8. Ohio State University 0.01 4.6 2000 Could convert to Could convert to oxide aluminide heI fuel yf

9. University of Washington 0.1 7.5 1989 Could convert to oxide fuel p+ 10. Purduc University 0.01 3.0 1986 Could convart to aluminide fuel II
11. University of Florida 0.1 4.8 7007 Converting to 31 LEU.

37

12. Rensselaer Polytechnic Institute 0.0001 5 2003 37 Approx.Annualnurnup21.h y y *) 13. Westinghouse (Illinois) 0.01 0.1 7004 Approx. Annual Burnup 21 2/

po 14. University of Calif. (Santa Barbara) 0.000001 1.4 1994 Approx. annual burnup 21 According to Argonne fiational Laboratory analysis Must await development of silictde fuels 37 Relicense appilcations pending. Renewal projected to be approved for date shown.

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UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION U ' ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 1 /

          • April 28,1983 MEMORANDUM FOR: John F. Ah ommis ioner FROM: R. F. Fr . cut e ..or

SUBJECT:

REDUCING FUEL ENRICHMENT IN U.S.

RESEARCH REACTORS The ACRS has received your memorandum of March 17, 1983 requesting comments concerning what steps might be appro-priate to effect a reduction in the maximum fuel enrich-ment of uranium in U.S. reseat -h reactors.

Individual Members of the Committee have provided comments which are attached. It is hoped that these will be useful in considering those steps that might be appropriate re-garding a decrease in the maximum enrichment of fuel in U.S. research reactors.

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'. Comments by ACRS Members Regarding Reducing Enrichment of Fuel In U.S. Research Reactors Dr. Axtmann '

I concur with OPE's recommendation as reported in John Zerbe's letter to Commissioner Ahearne, dated 3/1/83.

Dr. Lewis The only reason I see for doing it is to establish goodwill vis-a-vis other less developed countries (LDCs) whom we don't trust with enriched material.

I am an elitist, and don't think we should punish the trustworthy to improve our ima,ge with the non-trustworthy. We have plenty of internal protection against proliferation. The only problem I see with U.S. research reactors is the large number of foreign students working on them. My advice - forget the whole thing.

Dr. ifark The main points I would like to make are:

a. Item (1) of OPE's recommendation would seem to be entirely appropriate as it is.
b. Item (2) would be better if it were modified to something like the following:

"that existing reactors must replace burned up HEU fuel with fuel having appreciably lower enrichment than the original if that would be technically feasible with existing fuel tech-nology at the time of refuelling; and, HEU should be replaced with LEU fuel as soon as that may be feasible at the time of the re-fuellin g. "

In regard to the above suggested change in Item (2):

a. This would be more consistent with the concerns identified in paragraphs ?, 3, and 4 of the Supplementary Information provided in the Commission's Statement of Policy in the Federal Register of 8/24/82; and

b 2.

, b. It should be indicated that by " appreciably lower '

enrichment" was intended, say, some level about half-way between the original and the 20% level (or closer to 20%, if possible) since cutting the excess over LEU in half would about double the mass required to produce an explosive device and thus constitute a significant reduction in the proliferation risk.

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.i # o UNITED STATES 8h^,~o NUCLEAR REGULATORY COMMISSION 3

a.,

q-j ,Ia ADVISORY COMMITTEE ON REACTOR SAFEGUARDS wass NoTou, p. c. rosss

  • ..* April 26,1983 9

l MEMORANDUM FOR: M. C. Gaske, Deputy Executive Director j l

FROM: W. Kerr, ACRS Member gp F. J. Remick, ACRS Membe M. W. Carbon, ACRS fiem e'r V # '

SUBJECT:

CONVERSION TO LEU FUEL In response to Commissioner Ahearne's question, we have the following comments:

1. Low enriched fuel for TRIGA reactors is commercially available and there is no problem in its use. Since TRIGA fuel is typically long lived,any facility now using HEU fuel may have considerable life left in its core. Immediate conversion would require dis-carding this core and purchasing a complete new LEU core. The penalty would be economic. Most university reactors receive financial assistance from DOE for the purchase of their fuel.

This source of funds is limited. A requirement for immediate conversion would likely cause shutdown of some university re-actors, which would have an adverse impact on research as well as on nuclear science and engineering education.

Immediate conversion could also produce another difficulty. A security problem would arise because the HEU fuel would soon become nonprotecting. The consequent required security measures might well cause the reactor facility to be shut down. The used fuel must be shipped in licensed shipping casks and only one or two of these are available. Furthermore , funding for transpor-tation and security, if required for a large number of units in j the same year, would far exceed the funds available from 00E.

2. For reactors using plate type fuel and operating at or below about 2 Megawatts, experience with LEU fuel now exists. This experience indicates no problem in using LEU fuel except a decrease in thermal flux of up to about 107, for a given power level . Since there ap-pears to be no problem in mixing LEU and HEU elements, it makes sense from an economic viewpoint to use the existing HEU fuel that is now on hand rather than discarding it. (Typical element life at continuous operation is less than a year.)

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M. C. Gaske 4/26/83 ,

(3) For the high power university research reactors (MIT, Ga.

Tech, and Missouri), +.he use of LEU fuel will produce a significant degradation in capability because of the tight core geometry already required to achieve high core flux.

Assuming continued financial assistance to obtain new LEU fuel, the conversion to LEU fuel should not have significant adverse impacts on university reactors, except for a few high power, high flux reactors.

Since the capability of these reactors will be severely degraded if LEU fuel is used, these reactors should be pemitted to continue to operate with HEU fuel until alternative fuel, which does not degrade their functional capability, has been developed.

This discussion does not consider DOE reactors or the NBS research reactor.

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