An extension of the two-zone method for evaluating a fission gas release under an irradiation-induced resolution flux

• Published in: Journal of nuclear materials Vol. 373; no. 1; pp. 280 - 288
• Main Authors: Cheon, Jin-Sik, Koo, Yang-Hyun, Lee, Byung-Ho, Oh, Jae-Yong, Sohn, Dong-Seong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2008; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; 66.30.−h; 28.41.Ak; Gas release; Concentration effect; Diffusion equation; Fission gas; Adaptive method; Grain boundary; Nuclear reactor
• DOI: 10.1016/j.jnucmat.2007.06.008
• ISSN: 0022-3115

This paper describes an extension of the adaptive two-zone method whose accuracy is substantially enhanced when compared to the original formulation by Matthews and Wood. A diffusive problem under the presence of an irradiation-induced resolution flux is evaluated by applying a variational principle to the diffusion equation. Prior to a gas saturation in the grain boundaries, a constraint associated with a gas balance is added to the variational equation. The spherical grain is divided into two regions whose interface is relocated as the ratio of the number of gas atoms within a grain to that generated. The distribution of the gas concentration is calculated over the grain. During the calculations, the number of degrees of freedoms is reduced to provide a profile which decreases monotonically along the radius. Numerical verifications show that the present approach is viable in computing a gas release accurately and efficiently in fuel performance codes.