Fabrication of the fuel cladding tube having double graded layer by slurry dipping

*; Watanabe, Ryuzo*

PNC TJ9601 93-004, 68 Pages, 1993/03

PNC-TJ9601-93-004.pdf:4.56MB

Molybdenum/stainless steel functionally gradient material (FGM). which will be used as long life fuel cladding tubes in the fast breeder reactor, has been fabricated by slurry dipping and sintering process emphasizing the increase in unti-corrosion against liquid sodium and fission products. Slurries of different compositions were prepared by mixing the appropriate amount of molybdenum and stainless steel powders in the ethanol. Green compacts giving cylindrical shape, substrates. were formed by die pressing of stainless steel powders. The substrates were dipped in the slurry, dried in the air and CIP'ed stepwizely: they were encapsulated in Pyrex glass tubes and then HIP'ed 2h at 1573K at the pressure of 150MPa. The microstructural observation in the cross section of the sintered compacts revealed that the uniform dipped layer was formed and there was no defect such as large residual pores or small cracks. A defect free Mo/stainless steel FGM was successfully fabricated by the slurry dipping and sintering process, however, in the case of single phase coating of Mo layer on the stainless steel substrate, the serious delamination was observed. Some oxides and compounds were detected in the FGM layer by the use of SEM-EDX and EPMA analysis.