No abstract

No abstract

The objective of this conference was to exchange information and prepare further collaboration concerning the program of lowering the fuel enrichment of research and tests reactors.In 1994, a program for developing fuel elements and fuel assemblies for research reactors using fuel with 20% 235 U enrichment was initiated, which is part of the US program on lowering fuel enrichment used in research reactors. The Russian part of the program included the continuation of the development of fuel elements and assemblies for VVR-M2, IRT-3M, and MR with uranium dioxide fuel, development of high-density fuel, as well as fuel elements and assemblies of VVR-M5, IRT-3M, and IVV-10 reactors with such fuel [1].Development of IRT-4M Type Fuel Elements and Assemblies with Uranium Dioxide Fuel Enriched with 235 U to 19.7%. When decreasing the fuel enrichment to 19.7%, the 235 U content must be increased as compared with 36% enrichment fuel. To this end, in 1994 the Kurchatov Institute started the development of IRT-4M fuel assemblies, which are similar to IRT-3M assemblies, in which the widths of the fuel assemblies were increased from 1.4 to 1.6 mm, and the widths of the gaps between them were decreased from 2.05 to 1.85 mm, respectively. For this gap width, the water velocity in them will decrease by no more than 5%. The kernel thickness was increased from 0.4 to 0.7 mm, and the nominal cladding thickness is 0.45 mm, which is adequate for maintaining seal tightness [2]. For 400 g 235 U content in the eight-tube IRT-4M fuel assembly, the uranium content in the kernel is 3.85 g/cm 3 (Fig. 1).In May 1996, testing of individual size-types of fuel elements, perfected by the Novosibirsk Chemical Concentrates Works, as part of an experimental fuel assembly (Table 1) began in IR-8 without waiting for the technology for fuel elements of all sizes for IRT-4M fuel assemblies to be perfected. The tests were performed under the following conditions:

No abstract

No abstract