Switching FRG-1 to low-enriched fuel

In 1978 and 1979, the International Nuclear Fuel Cycle Evaluation (INFCE) was conducted within the framework of IAEA. One important result of that international effort to reduce the proliferation risk was the reduction of the U-235 enrichment used in many research reactors from 90% or 93% to less than 20% (which is no longer attractive to weapons production). This was to be achieved without exerting a more than marginal influence on the neutron flux available for experiments and on the fuel cost. New high-density fuel had to be developed to achieve this lower enrichment, and a large number of benchmark calculations and specific calculations had to be performed for conversion of the reactor. The new fuels were developed by Nukem (D), Cerca (F), and Babcock and Wilcox (USA). They were tested mainly in the ORR in the United States of America, but also in other reactors, such as the FRG-2. The results of development and testing are outlined both in the progress reports of the annual conferences and in IAEA publications. The basic calculations were carried out under the auspices of IAEA, the author having been in charge of German activities. (orig.)