Neutron shielding of the GDT (Novosibirsk) neutron generator project. A feasibility study

The paper presents results of extensive neutronic studies of the neutron source test facility based on the Novosibirsk Gas Dynamic Trap (GDT). The facility is to provide 10¹⁸ DT-neutrons/s (over a continuous 10-year period) for material-test studies. The paper examines the protective-shield capacity,to ensure survival of GDT vital parts and suggests design modifications when survival is in jeopardy. The numerical studies used the 3D-AMC-VINIA Monte Carlo code with a precise computer representation of the sensitive parts of the facility. Intensity maps were plotted for neutron fluences, displacements, heat deposition, etc. Shielding feasibility has been ascertained, and the lifetime of consumable components ensured beyond the recommended values. A modification is suggested to extend the irradiation space at HARD neutron energy spectra to increase the volume to 1 m³ with damage gradients <5%/cm. The design achieves neutron fluences close to 10¹⁴ n/cm²s (3.10²² n/cm² end-of-life) in a>100 l test space