Speaker
Dr
Michel Herm
(Karlsruhe Institute of Technology)
Description
Cladding tubes of water-cooled nuclear reactors are usually made of Zircaloy and are an important retaining element for radionuclides present in the fuel. However, cladding integrity is affected by various processes during reactor operation and beyond, e.g. oxidation, hydrogen uptake, PCI, fission product precipitation, alpha-decay, and radiation damage. Using experimental and modelling methods, the radionuclide inventory of an irradiated Zircaloy-4 plenum section is analyzed.
Quantities of U-235/238, Np-237, Pu-238/239/240/241/242, Am-241/243, Cm-243/244 besides C-14, Fe-55, Sb-125, Cs-134/137 were (radio-)chemically determined in digested Zircaloy-4 subsamples. Measured inventories of activation products in the Zr-alloy are in good agreement with calculated values. However, amounts of actinides and fission products exceed the calculated inventory by factor ~50 (Pu isotopes) and ~120 (Cs-137). Excess Pu and part of excess Cs inventory originate from fuel residues on the inner cladding surface, whereas vast amount of cesium is volatilized from subjacent fuel pellets and transported to the plenum.
Primary author
Dr
Michel Herm
(Karlsruhe Institute of Technology)
Co-authors
Dr
Dieter Schild
(Karlsruhe Institute of Technology)
Dr
Ernesto González-Robles
(Karlsruhe Institute of Technology)
Dr
Jörg Rothe
(Karlsruhe Institute of Technology)
Dr
Kathy Dardenne
(Karlsruhe Institute of Technology)
Mr
Nikolaus Müller
(Karlsruhe Institute of Technology)
Dr
Ron Dagan
(Karlsruhe Institute of Technology)
Dr
Volker Metz
(Karlsruhe Institute of Technology)
