Comparative analysis of non-destructive methods to control fissile materials in large-size containers

The analysis of various non-destructive methods to control fissile materials (FM) in large-size containers filled with radioactive waste (RAW) has been carried out. The difficulty of applying passive gamma-neutron monitoring FM in large containers filled with concreted RAW is shown. Selection of an active non-destructive assay technique depends on the container contents; and in case of a concrete or iron matrix with very low activity and low activity RAW the neutron radiation method appears to be more preferable as compared with the photonuclear one

Comparative analysis of non-destructive methods to control fissile materials in large-size containers

The analysis of various non-destructive methods to control fissile materials (FM) in large-size containers filled with radioactive waste (RAW) has been carried out. The difficulty of applying passive gamma-neutron monitoring FM in large containers filled with concreted RAW is shown. Selection of an active non-destructive assay technique depends on the container contents; and in case of a concrete or iron matrix with very low activity and low activity RAW the neutron radiation method appears to be more preferable as compared with the photonuclear one

Comparative analysis of non-destructive methods to control fissile materials in large-size containers

The analysis of various non-destructive methods to control fissile materials (FM) in large-size containers filled with radioactive waste (RAW) has been carried out. The difficulty of applying passive gamma-neutron monitoring FM in large containers filled with concreted RAW is shown. Selection of an active non-destructive assay technique depends on the container contents; and in case of a concrete or iron matrix with very low activity and low activity RAW the neutron radiation method appears to be more preferable as compared with the photonuclear one

Active Neutron Monitoring of Nuclear Fuel Cycle Fissile Materials

A decommissioning of nuclear fuel cycle facilities is inseparable from the problems of radioactive waste disposal. One of these problems is the categorization of a waste according to the content of beta- and alpha-emitters. Beta-emitters can be identified by existing technologies; however, the trouble arises when detecting alpha-emitting elements, primarily the long-lived members of the actinium chain with the specific activity of kBq/kg when they are spread inside a structural material. The report considers an application of an active neutron method-a differential die-away technology for reliable control of small quantities of FM. The essence of this method consists in sounding the interrogated item by pulsed thermal neutrons and recording the induced fission neutrons. The ratio of the number of fission neutrons to the number of source neutrons gives the normalized number of fission neutrons that is linked to the FM mass in the interrogated object. The work presents the scheme and principle of operation of an experimental device, as well as the results of measurement of concrete structures that contain internal traces of fissile materials. Analysis of the results shows that the proposed method allows the detection of ~ 6 mg of fissile material per kg of concrete with possible localization (cartogram) of the contaminated area

Active Neutron Monitoring of Nuclear Fuel Cycle Fissile Materials

A decommissioning of nuclear fuel cycle facilities is inseparable from the problems of radioactive waste disposal. One of these problems is the categorization of a waste according to the content of beta- and alpha-emitters. Beta-emitters can be identified by existing technologies; however, the trouble arises when detecting alpha-emitting elements, primarily the long-lived members of the actinium chain with the specific activity of kBq/kg when they are spread inside a structural material. The report considers an application of an active neutron method-a differential die-away technology for reliable control of small quantities of FM. The essence of this method consists in sounding the interrogated item by pulsed thermal neutrons and recording the induced fission neutrons. The ratio of the number of fission neutrons to the number of source neutrons gives the normalized number of fission neutrons that is linked to the FM mass in the interrogated object. The work presents the scheme and principle of operation of an experimental device, as well as the results of measurement of concrete structures that contain internal traces of fissile materials. Analysis of the results shows that the proposed method allows the detection of ~ 6 mg of fissile material per kg of concrete with possible localization (cartogram) of the contaminated area

Monitoring fissile and matrix materials in closed containers by means of pulsed neutron sources

Computational and experimental studies of the possibility of determining the fissile and matrix materials by means of differential neutron attenuation are presented. The time response of 235U fission under the action of 14 MeV neutrons from an ING-07T pulsed neutron generator, fabricated by VNIIA, on a 70-liter steel container holding uranium in graphite, iron and polyethylene matrices is analyzed. It is shown that milligram quantities of 235U can be detected and the matrix type and density as well as the location of fissile material inside a container can be determined.\ua92013 Springer Science+Business Media New York