Neutron-induced permeability of pyrocarbon-coated high-temperature gas-cooled reactor fuel particles

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · Nucl. Technol.; (United States)

OSTI ID:7211067

Bradley, R A ^[1]; Thiele, B A

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1. Oak Ridge National Lab., TN

Fuel for the high-temperature gas-cooled reactor is in the form of microspheres surrounded by high-density impermeable coatings to retain fission products. Recent irradiation tests indicated that the high-density carbon layer of Biso coatings may become permeable to krypton, xenon, and CO during irradiation. In-reactor gas release measurements showed the particles were impermeable to fission gases at the beginning of the test, but released significant quantities of krypton and xenon after a period of irradiation. Although postirradiation examination by visual, ceramographic, and radiographic techniques indicated that all particles were intact, gas content measurement showed that particles receiving a significant fast fluence contained only a small fraction of the expected krypton and xenon, while those receiving low fluence retained almost all the fission gas. The results of these experiments indicate that the permeability of the coatings is due to fast-neutron-induced structural changes in the pyrocarbon.

• OSTI ID: 7211067
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 35:2; ISSN NUTYB
• Country of Publication: United States
• Language: English

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