Non-destructive analyzer for nuclear fission products

The present invention provides a non-destructive analyzer for nuclear fission products suitable to the measurement of wastes containing transuranium elements which are handled in nuclear fuel cycle facilities. In the non-destructive analyzer for nuclear fission products, specimens to be measured are placed in a measuring chamber surrounded with neutron moderators. A detector for detecting fast neutrons from the specimens to be measured is disposed on the wall of the neutron moderators. A neutron source comprising radioactive nuclides and a neutron source rotational moving device for staying the neutron source in the measuring chamber at a time interval are disposed to the detector. With such a constitution, neutrons can be irradiated in the measuring chamber at a regular time interval without disposing a conventional neutron generators. Further, the radioactive nuclides as the neutron source have no limit in view of the frequency of use but have long life. Accordingly, it is not necessary to exchange them frequently, and they are excellent in the maintainability. In addition, since electric power sources are not necessary for generating neutrons, the operation is stable. (I.S.)