Neutronic Characteristics of the Novosibirsk GDT-NS Fusion Material Irradiation Facility

A summarized update of neutronic studies on the Novosibirsk Gas Dynamic Trap (GDT) fusion material irradiation facility (FMIF) is presented. The GDT-FMIF neutron source project is based on a mirror-type machine designed to produce 10¹⁸ D-T neutrons/s over 10 yr (3 × 10²⁶ neutrons). The proposed massive shielding, susceptible to further shield reductions and optimization, ensures proper shielding against radiation and/or heat overdeposition in accordance with project tolerances. The present shield configuration allows 3.3 m³ of irradiation space around the plasma column: 0.06 m³ receives 0.3 × 10¹⁴ thermonuclear uncollided 14-MeV n_DT-neutrons/cm²s (0.5 MW/m²), and 0.7 × 10¹⁴ with collision degraded energies (~0.7 MW/m² total), over 7 of the 8 m of intense flux axial length, the largest nontokamak availability. This allows the irradiation of large (up to 4.5 m long) life-size components (such as welds). The delivered neutron flux relative-gradients are small (< 6.3%/cm). Simulations use the 3DAMC-VINIA Monte Carlo code in its expanded version (drizzle-shower technique, two-step cascade, etc.), ENDF/B6 and EPDL nuclear data files, and a precise model of critical parts of the GDT. Results demonstrate that the GDT-FMIF is a very suitable irradiation test facility as per International Energy Agency specifications for an FMIF. With its 37.5-cm free depth of test space, GDT is the only dedicated facility suitable for a life-size blanket-tritium-breeding/extraction benchmark at a significant neutron flux level (2 MW/m²).