Comparison of calculated and measured radionuclide inventory of a Zircaloy-4 cladding tube plenum section. (6th March 2018)

• Record Type: Journal Article
• Authors: Herm, Michel; Dagan, Ron; González-Robles, Ernesto; Müller, Nikolaus; Metz, Volker
• Is Part Of: MRS advances. Volume 3:Number 19(2018)
• Page Start: 1031
• Page End: 1037
• Publication Date: 2018-03-06
• Subjects: actinide, -- nuclear materials, -- Pu, -- U, -- waste management; Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/adv.2018.274
• Languages: English
• ISSNs: 2059-8521

Abstract

ABSTRACT: Cladding tubes of water-cooled nuclear reactors are usually made of Zircaloy and are an important retaining element for radionuclides present in the fuel both during predisposal activities such as reloading of fuel assemblies from interim storage casks to final disposal casks and during final disposal in the case of canister breaching. However, cladding integrity is affected by various processes during reactor operation and beyond, e.g. fuel cladding chemical interaction and fission product precipitation onto the inner cladding surface. Using experimental and modelling methods, the radionuclide inventory of an irradiated Zircaloy-4 plenum section is analyzed. Quantities of 235/238 U, 237 Np, 238/239/240/241/242 Pu, 241/243 Am, 243/244 Cm besides 14 C, 55 Fe, 125 Sb, 154 Eu, and 134/137 Cs 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 ∼57 (minor actinides and non-volatile fission products) and ∼114 ( 137 Cs). Excess of minor actinides and part of enhanced Cs inventory originate from fuel residues deposited on the inner cladding surface during fuel rod fabrication, whereas vast amount of cesium is volatilized from subjacent fuel pellets and transported to the plenum.