Measurement and calculation of neutron leakage spectra from slab samples of beryllium, gallium and tungsten irradiated with 14.8 MeV neutrons

Y.B Nie,S Zhang,J Bao,Z.Y Zhou,H.X Huang,R Han,Y.Y Ding,J Ren,P Liu,X.C Ruan,H.C Wu,A Plompen,P Siegler,F.-J Hambsch,W Mondelaers,J Heyse,S Oberstedt,P Schillebeeckx,S Kopecky

doi:10.1051/epjconf/201714606014

Abstract

In order to make benchmark validation of the nuclear data for gallium (Ga), tungsten (W) and beryllium (Be) in existing modern evaluated nuclear data files, neutron leakage spectra in the range from 0.8 to 15 MeV from slab samples were measured by time-of-flight technique with a BC501 scintillation detector. The measurements were performed at China Institute of Atomic Energy (CIAE) using a D-T neutron source. The thicknesses of the slabs were 0.5 to 2.5 mean free path for 14.8 MeV neutrons, and the measured angles were chosen to be 60∘ and 120∘ . The measured spectra were compared with those calculated by the continuous energy Monte-Carlo transport code MCNP, using the data from the CENDL-3.1, ENDF/B-VII.1 and JENDL-4.0 nuclear data files, the comparison between the experimental and calculated results show that: The results from all three libraries significantly underestimate the cross section in energy range of 10–13 MeV for Ga; For W, the calculated spectra using data from CENDL-3.1 and JENDL-4.0 libraries show larger discrepancies with the measured ones, especially around 8.5–13.5 MeV; and for Be, all the libraries led to underestimation below 3 MeV at 120∘ .

Highlights

Due to a very low melting point (29.78 ◦C) and a very high boiling point (2229 ◦C), Ga becomes an candidate element in Chinese Initiative Accelerator Driven Systems (CIADS) project for liquid–metallic coolant [1]
In the 3–10 MeV neutron energy range, the contribution comes from the continuous level of inelastic scattering ((n,n )C)
For 60◦, the calculated spectra with the CENDL-3.1 are overestimated about 15%

Summary

Introduction

Due to a very low melting point (29.78 ◦C) and a very high boiling point (2229 ◦C), Ga becomes an candidate element in Chinese Initiative Accelerator Driven Systems (CIADS) project for liquid–metallic coolant [1]. W is one of the most promising candidate for spallation targets and other structural materials of CIADS project, as well as an important material in fission and fusion devices [2]. Be is another important material in the fission and fusion devices for multiplying neutrons in the core of fission research reactors and in the blankets of Deuteron-Tritium (D-T) fusion reactors [3]. The accuracy of nuclear data files for Ga, W and Be is very important for nuclear device design. The purpose of this work is to validate currently available modern nuclear data files, especially the CENDL-3.1 file, by carrying out benchmark experiment

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Conclusion