The invention discloses a
nuclear fuel burnup depth measuring device based on active
neutron space intensity distribution and a measuring method thereof. The measuring device comprises a compact D-D
neutron source, a
neutron moderator and a gamma shielding body which wrap the D-D
neutron source in sequence, a conical neutron collimation hole channel formed in the
neutron moderator, and a thermal neutron
image detector system connected with the conical neutron collimation hole channel. The conical neutron collimation pore channel is arranged at a certain distance above the compact D-D
neutron source and is used for obtaining quasi-parallel neutron beams. Because the thermal neutrons and different elements in the
nuclear fuel have different reaction sections, the neutron fluxes of the conical neutron collimation pore channels penetrating through the
nuclear fuel element sample are different in space, and the
burnup depth space distribution and the average
burnup of the nuclear fuel element are measured according to the established
response model of the thermal neutron
transmission intensity and the fuel burnup. The method belongs to a novel nuclear fuel burnup non-destructive analysis technology, and has the characteristics of rapidness, accuracy, no damage and good spatial resolution.