A cold pack with enhanced heat dissipation capacity, a reactor-based cold
neutron source, and a reactor belong to the field of
nuclear technology. The cold pack with enhanced heat dissipation capacity includes a moderator input
pipe, a moderator output
pipe, a cold pack cavity, and a
coolant circulation loop. The moderator input
pipe includes an inflow section and a curved return section. The cold pack cavity is connected to the return section and located on one side of the inflow section, with its maximum cross-section covering the
azimuth area of the
neutron conduit. The
coolant circulation loop includes an input jacket, an output jacket, and a
coolant cavity. The coolant cavity encloses the cold pack cavity, the return section, and part of the inflow section, with the space between the cold pack cavity and the inflow section located within the coolant cavity. This cold pack provides a larger volume of coolant for heat dissipation, effectively improving the heat dissipation capacity and cold
neutron output efficiency of the cold pack during neutron moderation.