Radiation and Nuclear Physics Aspects of the Use of the Thorium Fuel Cycle in a Hybrid Fusion Facility

Abstract

This paper presents the results of the experimental determination and computational simulation of the ambient dose equivalent rate for a metallic thorium cylindrical miniblock and the (n,2n), (n,f), and (n,γ) reaction rates in a thin ²³²Th metal foil irradiated with neutrons of the NG-24M generator spectrum. The ambient dose equivalent rate was determined by dosimeters-radiometers. The reaction rates were determined by the activation method using Ge spectrometers without destroying the irradiated samples. Computational simulations of ambient dose equivalent and reaction rates were performed, respectively, using the radiation transport codes PHITS, MCNP5, and KIR2, which use various nuclear data libraries: JEFF-3.2 and -3.3; JENDL4.0; ENDF/B-VII.0, -VII.1, and -VIII.0; ROSFOND; FENDL; and TENDL. The authors give an estimate of the ²³²U/²³³U relative accumulation upon natural thorium irradiation in a fusion facility blanket with defined neutron spectrum. The nonirradiated and irradiated thorium nuclide composition change simulation and visualization were performed using analytical solutions of an ordinary system of homogeneous linear differential equations describing nuclide transmutations.

Keywords:

• Thorium fuel cycle
• DEMO-FNS fusion reactor
• NG-24M neutron generator
• rate reactions

Acknowledgments

The KIR2 calculations were carried out using the computing resources of the federal collective usage center Complex for Simulation and Data Processing for Mega-Science Facilities at the NRC Kurchatov Institute.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Notes

^a Suppressed fission is one of the criteria indicating that ${\mathrm{\Sigma }}_{n,f}^{232\mathrm{T}\mathrm{h}}<{\mathrm{\Sigma }}_{n,2n}^{232\mathrm{T}\mathrm{h}}$ (proposed in this work).

Additional information

Funding

This research was carried out with the financial support of the Russian Foundation for Basic Research in the framework of scientific projects 19-29-02028.