Department of Physics and Astronomy

Fission data measurements at IGISOL

AlFONS (Accurate fission data for nuclear safety) is a project to make precision measurements of fission yields, i.e. the ratios of various fission products.

For this end, we are using the mass separation facility IGISOL at the University of Jyväskylä. Fission is induced in actinides by neutrons, thermal and high energy, and the result is studied.

We have developed a special neutron source for these experiments, utilizing the 30 MeV proton beam available in Jyväskylä. The protons collide with a beryllium target, inducing nuclear reactions that emit neutrons.

It is of important to improve the understanding of the fundamental physices in the fission process. Better data for fission yields makes it possible to improve predictions of the composition of nuclear fuel, and therefore also improve the neutron economy of a reactor. Calculations of this and other parameters in a nuclear reactor are at present depending on corrections using data from measurements during the monitoring of the reactor in operation. To reduce the uncertainties in the calculations of the fuel history inside the reactor core can improve the reactor safety as well as economy.

Better data is also important for considerations around final storage, and for development of new reactors of Generation IV. Fission yields determine the inventory of fission products, and hence the remaining decay heat in the used fuel during the first decades after removal from a reactor.

Selected publications

A. Solders, D. Gorelov, A. Jokinen, V.S. Kolhinen, M. Lantz, A. Mattera, H. Penttilä, S. Pomp, V. Rakopoulos, S. Rinta-Antila
Accurate fission yields for nuclear safety arXiv:1303.2829.

M. Lantz, D. Gorelov, A. Mattera, H. Penttilä, S. Pomp, D. Rados, I. Ryzhov and the IGISOL group
Design of a neutron converter for fission studies at the IGISOL facility
doi:10.1088/0031-8949/2012/T150/014020

M. Lantz, D. Gorelov, A. Jokinen, V.S. Kolhinen, A. Mattera, H. Penttilä, S. Pomp, V. Rakopoulos, S. Rinta-Antila, A. Solders
Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies arXiv:1304.2648.