Abstract: The invention relates to nuclear engineering and more particularly to controlled reactor start-up. The invention addresses a secondary startup neutron source by creating additional safety barriers between the coolant and the source active part materials. The secondary startup neutron source is designed as a steel enclosure housing an ampule containing antimony in the central enclosure made of a niobium-based alloy unreactive with antimony, with a beryllium powder bed located between the antimony enclosure and the ampule enclosure. An upper gas collector, located above the ampule serves as a compensation volume collecting gaseous fission products. The ampule is supported by a reflector and a bottom gas collector. The gas collectors, reflector, ampule enclosure and washers are made of martensite-ferrite grade steel.

Abstract: The invention relates generally to nuclear engineering and more particularly to controlled reactor start-up. The invention improves reliability of an operational neutron source by creating additional safety barriers between the coolant and the source active part materials. The operational neutron source is designed as a steel enclosure housing an ampule containing antimony and beryllium with separate antimony and beryllium cavities positioned coaxially. The antimony is contained in the central enclosure made of a niobium-based alloy unreactive with antimony. A beryllium powder bed is located between the antimony enclosure and the ampule enclosure. The ampule enclosure is made of martensite-ferrite steel poorly reacting with beryllium. An upper gas collector is located above the ampule, which serves as a compensation volume collecting gaseous fission products. At the bottom, the ampule is supported by a reflector and a bottom gas collector.