HELIOS: Irradiation Of U-Free Fuels And Targets For Americium Transmutation
- European Commission, Joint Research Centre, Institute for Energy - P.O. Box 2, 1755 ZG Petten (Netherlands)
- European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O.Box 2340, 76125 Karlsruhe (Germany)
- Nuclear Research and Consultancy Group, Dept. of Fuels, Actinides and Isotopes, P.O. Box 25, 1755 ZG Petten (Netherlands)
- Commissariat a l'Energie Atomique, CEA/DEN/DDIN, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France)
- Commissariat a l'Energie Atomique, DEC/SESC/LC2I, CEA-Cadarache, 13108 St Paul lez Durance Cedex (France)
- Electricite de France, EDF/Clamart, 1 Avenue du General de Gaulle, 92141 Clamart Cedex (France)
Americium is one of the radioactive elements that contributes to a large part of the radiotoxicity of nuclear spent fuel. Transmutation by irradiation in nuclear reactors of long-lived nuclides like {sup 241}Am is, therefore, an option for the reduction of the mass and radiotoxicity of nuclear waste. The analysis of previous irradiation experiments which were carried out with targets of MgAl{sub 2}O{sub 4}+11wt%{sup 241}Am showed that the release/trapping of helium is the key issue for target design. In fact, in those experiments a significant volume swelling was observed which was partly attributed to the production of helium, which is characteristic for {sup 241}Am transmutation. These findings led to the conclusion, that a new experiment should be designed in such a way that helium shall be released from the target already during irradiation. Such release of helium might be achieved either with a fuel temperature kept sufficiently high during the whole irradiation or with release paths for helium created by inclusion of tailored open porosity in the targets. A new irradiation experiment called HELIOS is currently being designed and will be carried out in the High Flux Reactor (HFR) in Petten (The Netherlands) in the frame of the 4-year project EUROTRANS of the EURATOM 6. Framework Programme (FP6). The main objective of the HELIOS irradiation is to study the in-pile behaviour of U-free fuels and targets such as CerCer (Pu, Am, Zr)O{sub 2} and Am{sub 2}Zr{sub 2}O{sub 7}+MgO or CerMet (Pu, Am)O{sub 2}+Mo in order to gain knowledge on the role of the microstructure and of the temperature on the gas release and on fuel swelling. The irradiation temperature will be high enough to be able to tune the release of a significant fraction of helium produced so that the material swelling can be minimised as much as reasonably possible. Besides, the irradiation duration has been chosen as a compromise such to ensure that the central temperature in the (Pu,Am,Zr,Y)O{sub 2} pellets be always higher than that of the (Am,Zr,Y)O{sub 2} pellets in order to be able to investigate, during the Post-Irradiation Examinations (PIE), the influence of the higher irradiation temperature on the helium release. The HELIOS irradiation experiment is planned to be carried out in the HFR core and shall last 300 full power days starting in the first quarter of 2007. The proposed irradiation position is a high flux position of the HFR core, which has a thermal flux of about 1*10{sup 18} m{sup -2}s{sup -1} and a total neutron flux of about 6*10{sup 18} m{sup -2}s{sup -} {sup 1}. The use of a high flux position is required in order to transmute a substantial fraction of the {sup 241}Am, within the planned duration of the HFR irradiation. In the present paper the fabrication procedure and the development of the HELIOS irradiation, its rationales and objectives are described and discussed. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21021074
- Resource Relation:
- Conference: 2006 International congress on advances in nuclear power plants - ICAPP'06, Reno - Nevada (United States), 4-8 Jun 2006; Other Information: Country of input: France; 7 refs; Related Information: In: Proceedings of the 2006 international congress on advances in nuclear power plants - ICAPP'06, 2734 pages.
- Country of Publication:
- United States
- Language:
- English
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