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Conference Article: Process study on advanced graphite-burn method for head-end step of HTR fuel reprocessing

Maeda, M.; Tsujino, T.; Iwamoto, K. (Department of Fuels and Materials Research, Japan Atomic Energy Research Institute, Toka-mura, Naka-gun, Ibaraki-ken (Japan))

Abstract

As a research related to the development program of VHTR in JAERI, process studies have been carried out on head-end step in the fuel reprocessing. The VHTR is planned to use TRISO-coated low enriched UO2 particles embedded in graphite matrix in the form of hollow cylinder called 'fuel compact'. The compacts are encased in graphite sleeve to make fuel rod, and then the rods are fabricated into prismatic fuel block. For this 'pin-in-block' type fuel, the modified Purex process would be essentially adaptable or the head-end treatment. Although the development except f of the head-end process has extensively been made in USA (2) and FR of Germany (3) on the process of '(Crush)-Burn-Grind-(Reburn)-Leach', various technical problems still remain there relating to the handling of a large volume of graphite containing 14C and highly radioactive powders, and to the treatment of the associated off-gas and solid wastes. The process principles of major steps in the proposed head-end flowsheet were experimentally shown. For the graphite burn with CO2 gas, an active catalyst of mixed Co-Na was found to promote the burning of graphite at 850 deg. C. Bench-scale experiments in a fixed bed and fluidized-bed show that the development of advanced reactor with high heat supply is the most important problem. For the decomposition of CO gas, an iron oxide was selected as an effective catalyst

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment Moscow (Russian Federation) 18-21 Oct 1983
International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria); State Committee on the Utilisation of Atomic Energy of the USSR, Moscow (Russian Federation)
IWGGCR--8, pp:345-356