"TITLE","AUTHORS","SUBJECT","SUBJECT_RELATED","DESCRIPTION","PUBLISHER","AVAILABILITY","RESEARCH_ORG","SPONSORING_ORG","PUBLICATION_COUNTRY","PUBLICATION_DATE","CONTRIBUTING_ORGS","LANGUAGE","RESOURCE_TYPE","TYPE_QUALIFIER","JOURNAL_ISSUE","JOURNAL_VOLUME","RELATION","COVERAGE","FORMAT","IDENTIFIER","REPORT_NUMBER","DOE_CONTRACT_NUMBER","OTHER_IDENTIFIER","DOI","RIGHTS","ENTRY_DATE","OSTI_IDENTIFIER","PURL_URL" "Migration behavior of palladium in UO{sub 2}, (3)","Yoneyama, Mitsuru; Sato, Seichi; Ohashi, Hiroshi [Hokkaido Univ., Sapporo (Japan)]; Ogawa, Toru; Ito, Akinori; Fukuda, Kousaku","22 GENERAL STUDIES OF NUCLEAR REACTORS; COATED FUEL PARTICLES; PALLADIUM; RADIONUCLIDE KINETICS; URANIUM DIOXIDE; HTGR TYPE REACTORS; TEMPERATURE DEPENDENCE; DIFFUSION; PRECIPITATION; URANIUM ALLOYS; MELTING; INTERFACES; QUANTITY RATIO; 220300; FUEL ELEMENTS","","Palladium (Pd) is easily released from UO{sub 2} kernels in HTGR coated fuel particles, and reacts with SiC coating layer. In addition, Pd is one of metallic fission products in irradiation UO{sub 2}, which constitutes in dissoluble residue in reprocessing of LWR fuels. In the present investigation, the migration of palladium in UO{sub 2} was examined by heating diffusion pairs sandwiched Pd foil between UO{sub 2} wafers at 1300 {approx} 1800degC. Experiments were also carried out on affinity of Pd to UP{sub 2} and a formation of U-Pd alloy. Pd was found mainly in the pores of UO{sub 2}. The maximum depth intruded by Pd in fairly large amount was more than 100 {mu}m for UO{sub 2} with 90%TD and 50{mu}m for UO{sub 2} with 95%TD, while the maximum length of open pores was 330 {mu}m for UO{sub 2} with 90%TD, and 50 m for that with 95%TD. Fused Pd wetted UO{sub 2} very much. Pd intruded deeply into UO{sub 2}, especially in the edge of Pd droplet. Furthermore, U was detected either in precipitates or the Pd source with {alpha}-Pd phase of U-Pd alloy containing Pd at about 10at%. This fact indicates that Pd highly reacts with UO{sub 2}. From the above results, the transport of Pd in UO{sub 2} was explained by the model of gaseous diffusion through pores in UO{sub 2}, which is retarded by formation of U-Pd alloy. It is also indicated that UPd{sub 3} forms even at the oxygen potential condition of O/U ratio, which is a little higher than 2.00 on the basis of thermodynamic calculation. (author).","","OSTI; NTIS; INIS","Japan Atomic Energy Research Inst., Tokyo (Japan)","","Japan","1992-08-01","","Japanese","Technical Report","","","","Other Information: PBD: Aug 1992","","Medium: X; Size: 55 p.","ON: DE93754309","JAERI-M-92-118","","Other: ON: DE93754309; TRN: JP9212174","https://doi.org/","","2008-02-12","10112611",""