Neutron capture and total cross-section measurements of 155Gd and 157Gd at ANNRI in J-PARC

Atsushi Kimura,Shoji Nakamura,Kazushi Terada,Nobuyuki Iwamoto,Jun-Ichi Hori,Toshiyuki Fujii,Osamu Iwamoto,Hideo Harada,Tatsuya Katabuchi,Yuji Shibahara

doi:10.1051/epjconf/202023901012

Abstract

Neutron capture and total cross sections of 155Gd and 157Gd were measured with the neutron time-of-flight method in Accurate Neutron-Nucleus Reaction measurement Instrument at Material and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex using the NaI (Tl) spectrometer and Li-glass detectors. Preliminary cross sections were obtained in the neutron energy region from 4 meV to 100 meV. The derived cross sections agree with evaluated values in JENDL 4.0 and the experimental results by Mastromarco but were not consistent with those by Leinweber.

Highlights

Gadolinium (Gd) is used as a burnable poison to compensate for decrease in reactivity under operations of commercial light water reactors, since two nuclides, 155Gd and 157Gd, have large capture cross sections for thermal neutrons
The capture cross section data of 155Gd and 157Gd at neutron energy of 0.0253 eV available in the literature are summarized in Table 1 with comparison to evaluated values in JENDL 4.0[1]
By taking ratios of capture yields, uncertainties due to neutron intensity and detection efficiency of the spectrometer were canceled out, absolute neutron capture cross sections are deduced with high accuracy

Summary

Introduction

Gadolinium (Gd) is used as a burnable poison to compensate for decrease in reactivity under operations of commercial light water reactors, since two nuclides, 155Gd and 157Gd, have large capture cross sections for thermal neutrons. It is essential for safe and reliable operation of nuclear power plants to know accurate values of neutron capture cross-sections of these nuclides. [2] neutron capture and total cross sections of 155and157Gd were measured with a TOF method at Accurate Neutron Nucleus Reaction measurement Instrument (ANNRI) in Japan Proton Accelerator Research Complex (J-PARC) Some researchers have pointed out that the current evaluation of the cross section for 157Gd is inconsistent with results of some integral experiments. [2] neutron capture and total cross sections of 155and157Gd were measured with a TOF method at Accurate Neutron Nucleus Reaction measurement Instrument (ANNRI) in Japan Proton Accelerator Research Complex (J-PARC)

Facilities and samples

Capture cross-section measurement

Total cross-section measurement

Conclusion