Determination of Disposal Density of VVER-1200 Spent Fuel Loaded Canisters in Horizontal Geological Disposal – G. Özesme, B. Bulut Acar

Geological disposal is a widely accepted method for permanent disposal of spent nuclear fuel and high-level waste. There are various geological disposal concepts under development in many countries and these concepts have differences mainly in the geometry and material of disposal canisters, geological formations of host rock and orientation (vertical and horizontal) of disposal canisters. The aim of this study is to perform thermal analysis of canisters loaded with VVER-1200 spent nuclear fuel assemblies and disposed horizontally in the granitic rock formation. The ANSYS Mechanical APDL 19.2 finite element code is utilized to perform thermal analysis. In the first part of the study, VVER-1200 spent nuclear fuel characteristics (amount, isotopic composition, heat generation rate, etc.) are evaluated by using the MONTEBURNS 2.0 code. Then, 3-dimensional ANSYS model of geological repository consisting horizontally disposed canisters, buffer material, and host rock regions is developed and transient thermal analysis is performed. As a result of the study, minimum distances between disposal canisters are determined by taking into account the thermal constraints for the components of the geological repository.

Keywords: ANSYS, Geological disposal, Monteburns, Spent nuclear fuel, VVER-1200