Shielding design for IECF devices: ensuring safety through material analysis

Inertial Electrostatic Confinement Fusion (IECF) devices have garnered increased recognition for their potential as compact, portable neutron sources for use in the generation of medical isotopes and various neutron-based interrogation techniques. This study investigates the shielding requirements for a laboratory enclosure that houses a deuterium-deuterium (DD) fueled IECF device. The simulation framework was first validated by reproducing the ambient dose equivalent, H*(10), conversion coefficient reference values, confirming the suitability of Geant4 for dose deposition measurements. Simulations were then used to evaluate neutron moderation and removal in various shielding materials, investigating five different concrete constituents and water, with the performance assessed relative to UK Ionising Radiations Regulations 2017 (IRR17) dose-rate limits. Neutron and gamma fluences were tallied in defined volumes of 40cm3, H*(10) measurements were then calculated using ICRP 74 conversion coefficients. The simulation results show that an IECF device can be operated safely at a neutron rate of 1×105ns−1 within public dose limits, recording <500nSvh−1 at a distance of 1.6m, with 10cm of all concretes tested other than Barite (Heavy) concrete, which measured 501nSvh−1. The results also show that a safe environment for radiation workers can be constructed, allowing the device to be operated at 1×107ns−1 if 30cm of water or ordinary concrete (OC1) is employed. The findings contribute to the understanding of optimal shielding configurations required to mitigate neutron radiation from IECF devices. Ensuring adherence to regulatory safety standards is paramount in the deployment of these fusion devices within populated areas. This research underscores the importance of selecting appropriate materials and thicknesses to achieve effective radiation protection, thereby facilitating the safe operation of IECF devices and contributing to advancements in medical isotope production and neutron-based interrogation technologies.