Battelle Memorial Inst., Columbus, Ohio
Pages: 12 Published: Jan 1960
Recent work on fabrication development, laboratory evaluation, and reactor evaluation of fueled graphite is reviewed.
Methods of preparing fueled graphites are discussed with respect to possible differences in reactor perlonnance and processing costs. Geometries and fuel loadings that have been achieved are mentioned. Data are given on variation in physical properties with fuel content.
The experimental evidence presented indicates that neutron plus fission fragment irradiation at temperatures of about 1300 F tends to cause the matrix structure to change from graphite to disordered carbon.
With respect to dimensional distortion, the individual effects of fission fragment and neutron irradiation at about 1300 F have been separated. Each appears to cause contraction. A relationship between dimensional distortion and the number ol fission fragments attenuated in the matrix is suggested.
Fission product release from a number of types of fueled graphites are reported. Results of both laboratory heat-treatment studies following low-temperature, low-exposure irradiation and high-temperature in-pile studies indicated that the release of fission gases was the order of at least 1 per cent of those calculated to be present.
Methods for improving fission product retention are discussed. The experimental evidence presented indicates that surlace coatings, impervious graphite, and impervious cladding for fuel particles have some potential.
Available data on chemical reactions between fuel compounds and the graphite matrix are discussed briefly.
Recommendations for future developmental work are included. Emphasis should be placed on improved fission product retention and studies of radiation effects at high exposures.
Paper ID: STP39609S