Measurement of the234U(n,f) cross section in the energy range between 14.8 and 17.8 MeV using Micromegas detectors

A Kalamara,V Michalopoulou,M Kokkoris,A Stamatopoulos,N Patronis,R Vlastou,S Chasapoglou,Z Eleme,A Lagoyannis

doi:10.1051/epjconf/202023905005

Abstract

The234U(n,f) reaction cross section was measured for three neutron energies 14.8, 16.5 and 17.8 MeV, relative to the238U(n,f) reference reaction. The in-beam measurements were carried out by using a set-up based on Micromegas detectors, while the quasi-monoenergetic neutron beams were produced by means of the3H(d,n)4He reaction at the 5.5MV Tandem T11/25 Accelerator Laboratory of the National Center for Scientific Research "Demokritos" in Athens (Greece). Additionaly,α-spectroscopy measurements were performed in order to determine the active mass of the samples and the corresponding impurities. In order to estimate the fission-fragment detection efficiency, Monte Carlo simulations were carried out using the GEF and FLUKA codes. Furthermore, simulations were also performed by coupling the NeuSDesc and MCNP5 codes for the determination of the neutron energy distribution in all the irradiated samples and the results were used in order to correct for the contribution of low energy parasitic neutrons in the fission yield. The final cross section data are presented, along with the methodology adopted for the treatment of the parasitic neutrons.

Highlights

Neutron-induced cross sections on actinides are an important element in the design studies for the improvement of nuclear reactors, such as Accelerator Driven Systems (ADS) [1] and Generation-IV reactors (Gen-IV) [2]
Various datasets exist in literature for the 234U(n,f) reaction cross section in the energy range from meV to GeV, in the energy region between 14-18 MeV, only 7 datasets exist [5,6,7,8,9,10,11] that present discrepancies up to 12%, except for the data by Babcock [11], which differ by 60% from the other data
The 234U(n,f) reaction cross section was measured at three incident neutron energies covering the range between 14.8 and 17.8 MeV and the results are presented in Fig. 6, along with previously existing datasets obtained from EXFOR [22] and the latest evaluations from ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0, CENDL-3.1 and TENDL-2017 libraries [16]

Summary

Introduction

Neutron-induced cross sections on actinides are an important element in the design studies for the improvement of nuclear reactors, such as Accelerator Driven Systems (ADS) [1] and Generation-IV reactors (Gen-IV) [2]. These systems are planned to e ffectively address the important issues of the sustainable use of fuel resources, the proliferation of nuclear material and the transmutation of nuclear waste [3, 4]. The results at the 14.8-17.8 MeV region are presented, with the use of the 3H(d,n)4He reaction for the production of the neutron beams

Experimental part

Analysis

Results and discussion