Progress and pain with RERTR – 20 years on

30 November 1998

First the USA, then other countries have dragged their heels over converting research reactors from high to low enrichment fuel in line with the anti-proliferation targets set over 20 years ago. However, over the past couple of years, a renewed impetus has built up as progress in several areas has been achieved.

After years of agonisingly slow progress, the Reduced Enrichment for Research and Test Reactor programme (RERTR) is, in some respects, enjoying a second spring. There has been good progress in many very important areas, including the take-back of US origin spent fuel, the development of high density fuel, ongoing conversion studies, and new research reactor designs using low enriched uranium (LEU) fuel.

But there are still some major obstacles to be shifted before RERTR can be called a real worldwide success. In particular, no comparable activities in take back, fuel development, or conversion of reactors have been undertaken so far in Russia. Furthermore, in future the IAEA should be willing to play a more central role as demanded nearly 20 years ago in the conclusions to the International Fuel Cycle Evaluation (INFCE).


It took about 18 months after the last major decisions were made in the RERTR programme before real changes could be seen or practical actions taken. During 1996 there were signs that things were happening – but slowly. Now, there seems to be some real movement.

What have been the major events since 1994? In December of that year, the general situation of the RERTR programme could have been summarised by the headline of an article published in this journal in that month: “Operators beware – converting to LEU fuel seriously degrades your reactor’s performance and earns you little credit.”* To highlight the issues, participants at RERTR meetings had decided before and during 1994 that letters from these conferences should be directed to the US Secretary of Energy and the Russian atomic energy ministry, MINATOM. The last letter to the US, actually addressed to President Clinton, pointed out that the RERTR programme was in a state of stagnation and must be recovered. It demanded from the US that:

• Promises to take back spent fuel of US origin should be honoured.

• Development of higher density fuel should be started so that all reactors could be converted, thus ensuring, to the greatest extent possible, that the penalties (in its negative impact on neutron flux, economics, safety and licensing) were not borne only by a few small or naive operators who believed in the goals of INFCE, but that the larger ones also carried the burden.

• An example for the international community should be set by converting university reactors and by following its own Federal Regulations relating to DOE and other reactors (MIT, Missouri, NIST). The US was asked to demonstrate publicly its willingness to convert these reactors to use the qualified U3Si2 fuels with density of 4.8 g(U)/cm3 and enrichment far less than 93%, as demanded in, for example, Fed Reg Note Vol 51 no 32, 18 February 1986.

It must be added that all letters sent to the US Secretary and to President Clinton have been answered. No reply has been received to either of the two letters sent to MINATOM.


We are now beginning to recover from a frustrating and, for many of us involved in this effort, agonising period which saw too few achievements. Within the last two years there has been significant progress in a number of areas which has been a relief and provided new momentum. At the same time, of course, other areas of this techno-political programme are still waiting for the necessary action. However, large US delegations present at the 20th (1997) and 21st (1998) RERTR meetings, demonstrated their willingness to drive forward in many major areas for the reduction of enrichment for research reactors.

The return of spent fuel of US origin for the 10 years to May 2006 is now a well established programme for MTR type fuel, with shipments from Canada, Europe, South America, Asia already being undertaken on a very routine professional basis. Establishing these shipments greatly increases the paper work and the controls on specific sites where the spent fuel elements are stored. But this has been achieved thanks to the efforts of all those involved at DOE Headquarters and the Savannah River Site, SAIC, Westinghouse, the transport companies and the licensing organisations. The licensing organisations involved in the revalidation of cask licenses in different countries are playing an increasingly key role to ensure that shipments go according to schedule.

To date, about 2000 of some 23 000 spent fuel elements (including Triga fuel) have been returned within this programme, and are now stored at the Savannah River Site. Some small changes have been made in the Record of Decision to improve the efficiency of shipments. The weakest point is still the availability and licensing or re-licensing of casks in different countries.

After a short litigation period in California, the first shipment of Triga fuel arrived at Concord Harbor. Others are scheduled. So the return of spent fuel of US origin (described in the Environmental Impact Statement of February 1996 and the Record of Decision of 13 May 1996) is going quite well on a professional routine basis, with the support of US government agencies and environmental protection groups, which accept them as a significant contribution to the reduction of the proliferation risks.

So why, if one approaches the US DOE for the supply of LEU to convert a reactor from HEU to LEU or to continue the operation of a converted reactor with LEU, is the reply: Sorry! We are not in a position to sell LEU, but HEU is available! Does the DOE’s right hand know what its left is or is not doing?


In 1996 the US-DOE started a new 5-year programme for the development of higher density fuel (up to 9 g(U)/cm3), which would allow all research reactors to convert to LEU. Fuel testing started two years ago with a screening test of twelve different uranium alloys or compounds, to allow selection of a number of these alloys as candidates for higher density fuel. In addition, CERCA, working in France with a smaller budget, started the development of two uranium-molybdenum alloys which show very interesting possibilities for high density fuel. It is being developed mainly for the 100 MW Jules Horowitz Reactor project, a materials testing reactor, which is intended to use LEU from its start-up in 2006.

This October the first results were due to be published on the irradiation tests showing convincing results for small microplates from post irradiation examinations (PIEs). Irradiations being made for densities up to 4.8 g(U)/cm3 and burn-up of up to 74%. For most of the candidates, (especially for uranium with 10% molybdenum content) the tests will be continued and PIEs made. Results will be available early in 2001. Normally, these tests would be followed by miniplate or fuel plate tests which will take an additional two years.

If the results are convincing, it may be decided that full fuel element tests should be the next step. Fabrication, irradiation, PIE reports, and final official qualification will take at least an additional 3 years after the PIEs in 2001. The scientific green light that the high density fuel has been qualified is not expected before 2004 – 2005 is more realistic. With the final positive qualification of this fuel the non-acceptable discrimination of other research reactors may come to a positive end. One can always dream!

With the high density fuel qualified by 2005, it is possible to estimate when the conversion of research reactors using this fuel can be expected: completion of conversion studies, safety reports and licensing process (2 years); procurement and shipment of fuel elements to the facility (2 years); reactor conversion (6 months to 4 years depending on the reactor design).

Therefore, conversion of these reactors will, taking an optimistic view, not be completed before 2010 - 2012. Assuming a 3-year decay time before this fuel can be shipped it is clear that the high enriched uranium at these facilities cannot be eliminated from the market before 2013 - 2015. This is far beyond the accepting policy for the return of spent fuel within the present US programme whose conversion and return dates are 2006 and 2009.


The US take-back programme for US origin fuel is a very important factor for the implementation of the RERTR in many countries. To low income countries it offers the free-of-charge return of their HEU and LEU (spent and fresh) to the US. This opportunity will be taken up by a large number of countries.

The take-back programme with free-of-charge return at present is without any comparable option for those countries having non-US origin fuel. Other countries selling uranium for research reactors, include China, France, the UK and Russia.

France is offering some reprocessing services for aluminide fuel, requiring the take-back of all reprocessed materials, including radioactive waste, and payment for all services. This offer can therefore be taken up only by owners of a few reactors and particularly not for research reactors converted to using U3Si2 fuel.

Letters to MINATOM from the IAEA and a large group of operators using fuel of Russian origin, have asked Russia for a take-back programme for spent fuel similar top that of the USA. They are still waiting for a reply.†

A Russian take-back programme is extremely urgent because today there are tons of HEU in spent fuel which have lost their self protection characteristics and have to be considered, as fresh fuel. In many cases, the fuel is not sufficiently physically protected either – certainly not safeguarded to the degree required for fresh uranium under the IAEA definitions.


Conversion studies are now underway for a few reactors and, for the first time, conversion is planned for some US DOE reactors. But there are no such studies for many reactors – even for the so-called unique purpose reactors for which the US Fed Reg Notes published in 1984 and 1986 demanded action. This probably explains why there were only very few US reactor operators among the large number of US participants at the RERTR meetings.

Thanks to the co-operation with the Argonne National Laboratory, conversion studies are now being started for reactors in the Czech Republic, Hungary, Poland and Uzbekistan. But the fuel for converting these reactors is far from being qualified in Russia, and conversion makes no real sense if there is no solution, such as the US take-back programme, for the spent HEU fuel stored at these and other research reactors constructed and fuelled by the former Soviet Union.

New reactors planned in Thailand, France, China and Australia are being designed to use LEU. France’s JHR, rated at 100 MW, is a real fillip for future RERTR activities. It demonstrates that France, in addition to the CERCA fuel development initiative, is willing to accept INFCE demands, including the large penalties in terms of flux and economics involved in the operation of a high power reactor with LEU fuel.

However, the decision of the University of Munich taken around 1985 to go ahead with the design of the FRM II with HEU fuel (just when the LEU silicide fuel with 4.8 g(U)/cm3 was close to being qualified) is still a clear challenge for the RERTR activities, undermining its progress and relieving the pressure on other defaulters. It will be very difficult to convince people to convert an existing reactor, when those building new ones are not willing to accept the operational and economic penalties. One of the major reasons for this situation is US policy: while the US has put pressure on other countries to convert their reactors, the DOE has been planning to construct a major research reactor, the Advanced Neutron Source, with HEU, and has not converted any domestic reactors for a good many years.

The possible design of FRM II with LEU fuel has been discussed again at the two latest RERTR meetings, and it seems to be accepted now, by the FRM as well as others, that this reactor can be built for use with existing qualified LEU and operated with the same or better safety margins. To achieve the same neutron flux, however, the power must be increased by 60% (if operated with LEU at the present designed 20 MW, there will be a reduction in flux by about 37%). Operators converting their reactors take a penalty of up to 20% in reduced thermal neutron flux.

The recent federal elections in Germany, which resulted in the formation of a coalition government of Social Democrats and Greens, has made the situation more difficult for FRM – the new government has already said that the possibility for changing the present HEU design to an LEU design would be examined.

It has also decided that the use of weapons grade uranium is highly problematical and is a matter of foreign policy concern. For this reason pressure will be applied for the conversion of the 5 MW FRM I reactor and the 23 MW FRJ-2 at Jülich to LEU fuel. LEU targets for Mo-99 production have been tested and it is now expected that these targets will be qualified for use in about two years time, or earlier.


A fuel development and testing programme is now in hand for UO2 fuel with densities up to 3.85 g(U)/cm3 for research reactors operated in Russia and in other countries using fuel of Russian origin. At the moment, many of the test plates have failed. As the density is close to the fabrication limits, some improvement in this area is clearly necessary. [The USA has offered to share know-how on silicide fuel fabrication (U3Si2 is being qualified up to 4.8 g(U)/cm3) free of charge to Russia, but still no tests of silicide fuel are being performed.] At the latest RERTR conference in São Paulo during October this year, no further information has been given on the failed Russian fuel plates. The only comment has been that the test of relatively low density (2.5 g(U)/cm3) UO2 fuel plates continue at Gatchina.

The first results from a joint US-Russian study on the conversion of one of the 16 Russian research reactors, the IR-8 in Moscow, have been presented. This reactor can be converted to 3.8 g(U)/cm3 fuel. In short, the Russian contribution to the RERTR activities is next to nothing.

Besides having significantly reduced its efforts in the field, MINATOM is offering – and signing contracts – to supply HEU for research reactors, including the FRM II in 1997 and the HFR-Petten in 1998. These reactors can be converted to LEU.

There are US/Russian studies at present on the conversion of three Russian plutonium production reactors, which are needed for the supply both of local heat and electricity, to use HEU with significant support by the US ($180 million). Calculations show that LEU could be used in these reactors.

There is an agreement on RERTR co-operation between US and China, but no details have been released for some years of any ongoing activities. Recently, a draft design for a new 60 MW reactor has been discussed. The reactor should use U3Si2 fuel of 4.3 g(U)/cm3.


The role of the IAEA is important and it is in a good position as a neutral organisation to play a central role, as the INFCE conclusions demand, in updating periodically the international status and progress of the UN programme to reduce the proliferation risk. To show the successes and failures will add weight to the whole RERTR programme. The IAEA has started with the collection of relevant data on the overall status of the back end issues (e.g. number of spent fuels of different origin, failed fuel, storage conditions, existence of spent fuel management plans). In addition the IAEA has stated that a take-back programme, like that of the USA, must be available for reactors built and fuelled by the former Soviet Union.


Looking at the successes and failures to date, it is a relief to see that the RERTR programme is being invigorated by important activities:

• The US programme for the take-back of US-origin fuel.

• Progress in developing and the qualifying high density fuel in the USA and at CERCA.

• Design of new reactors with LEU fuel, including the French JHR 100 MW reactor.

• Conversion studies being undertaken for more US reactors, including DOE-operated reactors

• Tests on Russian UO2 fuel with medium densities.

• Tests of LEU targets for molybdenum-99 production.

• Russian plans to convert the plutonium production reactors.

But there are a number of major hurdles in the way:

• The FRM II being designed for HEU.

• Relatively low activities in converting US reactors within the last two years.

• No take-back programme for fuel of Russian origin.

• Russian fuel development is fixed only on one fuel (UO2) and low densities.

• The USA is not following its own Fed Reg Notes from 1984 and 1986 in demanding the reduction of enrichment to intermediate levels for many high power US reactors including ATR, HFIR, HFBR, MIT, NIST, Missouri and others.

• Russia is offering and selling HEU to reactors which could now be converted to LEU.

• The new high density fuel will not be qualified before 2005, so the conversion of reactors wanting to use it will not be finished before 2010 to 2013. In addition, the present US take-back programme, which is terminated in 2006, will not include the take-back of this fuel, which is completely counter to the main intentions of this programme to reduce the proliferation risk.

• US/Chinese co-operation exists only on paper.

• The IAEA should continue presenting periodically the international status and progress of this programme.

There is some reason to believe that this second spring of the RERTR programme will last long enough for the goals formulated in 1980 to be reached mainly within the next decade. But this depends heavily on the approach to implementing enrichment reduction at the facilities so far unconverted. Excessive pressure, particularly by the USA, is not the right way. The only way to convince the defaulters to take the necessary action is by example.

There is still, therefore, hope that the RERTR programme will be a fair programme which can be carried out equitably worldwide for all research reactors.


Due to the increasing availability of technology and the spread of knowledge relating to nuclear weapons by the end of the 1960s, action was taken to reduce the threat of proliferation of nuclear weapons. The main steps involved were the establishment of the Non-Proliferation Treaty (1968), INFCE (1977-1980) and the passing of the US Nuclear Non-Proliferation Act (1978). The following passages are taken from the Summary Volume (1980) of INFCE. • “... effective measures can and should be taken at the national level and through international agreements to minimise the danger of proliferation of nuclear weapons without jeopardising energy supplies or the development of nuclear energy for peaceful purposes.” • “Proliferation resistance can be increased by: • Enrichment reduction, preferably to 20% or less, which is internationally recognised to be a fully adequate isotopic barrier to the weapons usability of U-235. • Reduction of stockpiles of highly enriched uranium. • Reduction of the annual production of fissile materials in research reactors, although attainment of weapons-usable material would require spent fuel reprocessing. For example, for some research reactors fuelled with natural uranium the proliferations resistance might be improved by utilising slightly enriched uranium, which reduces the annual plutonium production. It must be stressed that in an overall assessment of the proliferation resistance and safeguards of a particular research reactor, it is necessary to consider all of the above factors.” • “The delegates recognised the central role the IAEA has played in the past and must continue to play in the future in meeting the problems that were the focus of the INFCE study.”

Privacy Policy
We have updated our privacy policy. In the latest update it explains what cookies are and how we use them on our site. To learn more about cookies and their benefits, please view our privacy policy. Please be aware that parts of this site will not function correctly if you disable cookies. By continuing to use this site, you consent to our use of cookies in accordance with our privacy policy unless you have disabled them.