New measurement of the ²⁴²Pu(n,γ) cross section at n_TOF-EAR1 for MOX fuels: Preliminary results in the RRR

Abstract

Abstract. The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with 238 U to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. The use of MOX fuels in thermal and fast reactors requires accurate capture and fission cross sections. For the particular case of 242 Pu, the previous neutron capture cross section measurements were made in the 70's, providing an uncertainty of about 35% in the keV region. In this context, the Nuclear Energy Agency recommends in its "High Priority Request List" and its report WPEC-26 that the capture cross section of 242 Pu should be measured with an accuracy of at least 7-12% in the neutron energy range between 500 eV and 500 keV. This work presents a brief description of the measurement performed at n TOF-EAR1, the data reduction process and the first ToF capture measurement on this isotope in the last 40 years, providing preliminary individual resonance parameters beyond the current energy limits in the evaluations, as well as a preliminary set of average resonance parameters.

Radiative neutron capture on Pu242 in the resonance region at the CERN n_TOF-EAR1 facility

“…The measurement was carried out at n_TOF-EAR1 in 2015 and preliminary results have been already presented in Refs. [19,20]. While the measurement has provided data from thermal up to at least 200 keV, this paper deals only with the analysis of the resolved resonance region, which has been extended from 1.3 keV to 4 keV.…”