Future research program on prompt gamma-ray emission in nuclear fission

In recent years the measurement of prompt fission gamma-ray spectra (PFGS) has gained renewed interest, after about forty years since the first comprehensive studies of the reactions 235U(nth,f ), 239Pu(nth,f) and 252Cf(sf). The renaissance was initiated by requests for new values especially for gamma-ray multiplicity and average total energy release per fission in neutron induced fission of 235U and 239Pu. Both isotopes are considered the most important ones with respect to the modeling of innovative cores required for the fast Generation-IV reactors, the majority working with fast neutrons. During the last 5 years we have conducted a systematic study of spectral data for thermal-neutron induced ssion on 235U and 241Pu as well as for the spontaneous fission of 252Cf with unprecedented accuracy. From the new data we conclude that those reactions do not considerably contribute to the observed heat excess and suspect other reactions playing a significant role. Possible contributions may originate from fast-neutron induced reactions on 238U, which is largely present in the fuel, or from gamma-induced fission from neutron capture in the construction material. A first experiment campaign on prompt gamma-ray emission from fast-neutron induced fission on 235,238U was successfully performed in order to test our assumptions. In the following we attempt to summarize, what has been done in the field to date, and to motivate future measurement campaigns exploiting dedicated neutron- and photon-beams as well as upcoming highly efficient detector assemblies.

OBERSTEDT Stephan;  BILLNERT Robert;  HAMBSCH Franz-Josef;  LEBOIS M.;  OBERSTEDT A.;  WILSON J. N.; 

2016-01-04

SPRINGER

JRC95533

1434-6001,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC95533,   

10.1140/epja/i2015-15178-8,