This repository stores the data analysed within the paper: Article Title: Modelling a novel technique to remove excess decay heat from a geological disposal facility using a closed-loop geothermal system DOI: https://doi.org/10.1016/j.tsep.2024.103090 Editorial manuscript number: TSEP-D-24-00971 An overview of each excel spreadsheet is given below: Figure1: raw data for Figure 1 plotting Total Decay Heat on log scale (W/t) [column B] versus Cooling time on log scale (years) [column D]. Figure2: raw data for Figure 2 plotting a stacked histogram of chosen radionuclides percentage heat contribution (%) [columns B - X] versus Cooling time on log scale (years) [column A]. Table1: raw data depicting Half-lives (s) of desired radionuclides from nuclear databases JEF2.2, JEFF3.1.1, JEFF3.3, ENDF/B-VIII.0, ENSDF and DDEP. Table2: raw data for all UK reactor information, such as operation years and estimated fuel batch number. Table3: raw data for the total decay heat for three SNF types: AGR, PWR, and EPR at years 2040, 2045, and 2050. Table4: raw data for the total activity for three SNF types: AGR, PWR, and EPR at years 2040, 2045, and 2050. Table8: simulation data results from T2Well for temperatures and power at different parts of the lateral, for mass flow rates 2 kg/s and 8 kg/s at fixed distance z = 1.2 m away from the lateral. Table9: simulation data results from T2Well for temperatures and power at different parts of the lateral, for a fixed mass flow rate of 8 kg/s at distances z = 5 m, z = 10 m, z = 20 m, and z = 40 m away from the lateral. Figure4_raw_data: raw data on total decay heat vs cooling time for SNF types: AGR (black), PWR (blue), and EPR (red) Figure7_raw_data: simulation data on end lateral temperatures for T2Well (red), Matlab (blue), and OGS (cyan) for Figure 7. Figure 9 raw data folder: AGR.txt (black), EPR.txt (red), and PWR.txt (blue) raw data where sub-folders a, b, c, and d depict the results for Figures 9a), 9b), 9c), and 9d) respectively. Figure 10 raw data folder: AGR_.txt (black), EPR_.txt (red), and PWR_.txt (blue) raw data files for distances 5m (solid line), 10m (dashed line), 20m (dotted line), and 40 m (dot dashed line) within Figure 10.