Graphite corrosion and hydrogen release from HTR fuel elements in Q-brine
- Research Centre Juelich (Germany). Inst. for Safety Research and Reactor Technology
Industrial reprocessing for High Temperature Reactors (HTR) fuel elements has never been installed in Germany. The spent fuel elements are being considered for final disposal in a rock salt repository in the deep geologic underground. Safety analysis requires the assumption of an accidental water ingress into the repository, resulting in the formation of a concentrated salt solution with the typical composition of a quinary brine. After corrosive penetration of the container walls, the brine may finally contact the fuel elements directly and mobilize radionuclides. Duve et al. investigated the leaching of the fission products and actinides from HTR fuel elements in Q-brine. The mobilization of {sup 14}C by graphite corrosion is one of the last data bases required as a source term for the release estimation of radionuclides in the final safety analysis. The evaluation of the hydrogen release was prescribed by the licensing board, because an excessive gas pressure may affect the overall integrity of the geological barrier. {sup 14}C occurs as dissolved organic and inorganic compounds in the brine. The leaching rate or organic {sup 14}C decreases from about 80 Bq to 1 Bq. The amount of organic {sup 14}C decreases from about 80 Bq to 1 Bq during leaching. The release of inorganic {sup 14}C ceases within 4 months. About 100 ppm of the total {sup 14}C inventory was released during leaching. Gaseous {sup 14}C has never been detected. The gas formation is based on the radiolytic degradation of water, with a formation rate of 0.04 to 0.11 ml/d. Gas chromatographic analysis of the gas proved that hydrogen is the main component of the released gas. Tritium and {sup 85}Kr were detected as traces with radio gas chromatography.
- OSTI ID:
- 183001
- Report Number(s):
- CONF-950917-; ISBN 0-7918-1219-7; TRN: IM9608%%370
- Resource Relation:
- Conference: 5. international conference on radioactive waste management and environmental remediation, Berlin (Germany), 3-9 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Fifth international conference on radioactive waste management and environmental remediation -- ICEM `95: Proceedings. Volume 1: Cross-cutting issues and management of high-level waste and spent fuel; Slate, S.; Feizollahi, F.; Creer, J. [eds.]; PB: 900 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
SPENT FUEL ELEMENTS
UNDERGROUND DISPOSAL
AVR REACTOR
RADIOACTIVE WASTE DISPOSAL
THTR-300 REACTOR
RADIOACTIVE WASTE FACILITIES
WATER INFLUX
SAFETY ANALYSIS
GRAPHITE
CORROSION
GROUND WATER
FISSION PRODUCT RELEASE
FEDERAL REPUBLIC OF GERMANY
CARBON 14
RADIONUCLIDE MIGRATION
BRINES
GAS ANALYSIS
RADIOLYSIS
LEACHATES
EXPERIMENTAL DATA