Three-Dimensional Thermal Modeling of In Situ Heating Tests for High-Level Radioactive Nuclear Waste Repository

Abstract

This study aims to model the temperature evolution near the heater of an in situ heating test for a nuclear waste repository. Based on the governing equation of heat conduction, a mathematical model is established to obtain temporal and spatial temperature distributions in the in situ heating test. Then, semi-analytical solutions are derived using the Laplace and Fourier transforms and their inverse transforms. The corresponding results in the time domain are obtained by conducting the Crump method. The semi-analytical solution is applied to predict temperature change near the heater in two in situ heating tests. Finally, a parametric study is conducted to explore the impacts of some parameters on the temperature evolution of the buffer layer for one prototype repository in situ heating test. The results show that the semi-analytical solution of the proposed model can well predict the temperature change near the heater in the two in situ heating tests. The thermal conductivities of the buffer layer and the rock layer and the thickness of the buffer layer have significant effects on the temperature evolution of the buffer layer in the prototype repository in situ heating test.

Keywords:

• Semi-analytical solution
• in situ heating test
• nuclear waste repository
• temperature distribution
• disposal
• bentonite buffer layer

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work were financially supported by the National Natural Science Foundation of China with grant number 52238007 and the Natural Science Foundation of the Jiangsu Higher Education Institutions of China with grant number 23KJD560002.