METHOD OF MONITORING INTEGRITY OF SAFETY BARRIERS DURING DECOMMISSIONING OF URANIUM-GRAPHITE NUCLEAR REACTOR Russian patent published in 2019 - IPC G01V5/10 

FIELD: physics.

SUBSTANCE: invention relates to the technology of reconnaissance or detection using neutron radiation. Method to control integrity of safety barriers includes installation of inspection channels in the form of casing pipes in the number of at least three in places for logging, registration of the background spectrum, performance of pulsed neutron-neutron logging. Prior to creating safety barriers, pipes of side ionisation chambers are built up to a mark corresponding to the upper part of the waste disposal point; inspection channels are installed with height corresponding to the height of metal structures. Neutron detector is selected, which is successively placed into lateral ionization chambers and inspection channels and background neutron radiation is measured along the entire length of the channels. Collimated neutron source is introduced into the lateral ionization chamber and a neutron detector is placed in the inspection channel in parallel. Simultaneously lowering the source and the neutron detector, scanning the selected area of the barrier material and determining the place of formation of cavities and cracks in the barrier material from the value of attenuation of the neutron flux.

EFFECT: invention makes it possible to determine the location and size of cavities in clay-containing safety barriers.

1 cl, 2 dwg