NuFuel & MMSNF 2015

First Workshop on Research into Nuclear Fuel in Europe
and Materials Modeling and Simulation for Nuclear Fuels Workshop
Karlsruhe, Germany, November 16th to 18th, 2015

Updated: Tue 08 Dec 2015, 14:27

Talk 3.5: Long term structural stability of severely alpha-damaged fuels

Oliver Dieste, T. Wiss, D.H. Wegen, J.-Y. Colle, O. Benes, R.J.M. Konings, V.V. Rondinella
  • European Commission, Joint Research Centre, Institute for Transuranium Elements (ITU), Hermann-von-Helmholtz Platz 1, PO Box 2340, DE–76125 Karlsruhe, Germany

Abstract

During the irradiation of the most commonly used nuclear fuels, minor actinides like americium or neptunium are produced. Together with plutonium they will be responsible for the long term radiotoxicity of spent nuclear fuel, and for the medium term heat loading of the fuel in open nuclear fuel cycles. Increasing amounts of alpha-damage and helium during spent fuel storage and in the repository will be generated, as these transuranic elements are mainly alpha-emitters. In the SUPERFACT irradiation in the mid–80’s, a UO2 fuel containing 20 at. % Np and 20 at. % Am has been irradiated in the Phenix fast reactor to demonstrate the transmutation feasibility of such fuels. It was shown that as a consequence of the actinide loading and irradiation very large amounts of helium were generated corresponding to standard irradiated LWR fuels aged for a few hundred thousand years. This aspect was investigated as a contribution to assessing properties and behavior of very aged spent fuels. Additionally, UO2 samples doped with 238 Pu have been studied to characterize the effects of alpha-damage and helium production under accelerated conditions corresponding to spent fuel after storage/disposal time of centuries/thousands of years. In the present work we report on experimental observations of alpha-damage effects as well as helium release behavior in (Ux, 238 Pu1-x)O2 and in the irradiated (U0.6,Am0.2,Np0.2)O2 SUPERFACT samples by Transmission Electron Microscopy (TEM), and Electron Energy Loss Spectroscopy (EELS).

References
  1. Wiss, T., Dieste-Blanco, O., Tacu, A., Talip, Z., Colle, J.-Y., Martin, P., Konings, TEM study of alpha-damaged plutonium and americium dioxides, J. Mater. Res., 2015, vol. 30, pp. 1544–1554