Patent ID: 7902519

Claim:
A method of monitoring a volume of waste for radioactive material, the method comprising: providing the volume of waste in a monitoring space; providing a support, the support being provided with a plurality of detectors for radioactive material; monitoring the volume of waste for radioactive material, in four or more parts, to give a monitoring result for each of the four or more parts; correcting the monitoring result for each of the four or more parts for geometry and/or attenuation to give a corrected result for each of the four or more parts using a separate correction factor for each of the four or more parts; wherein the separate correction factor for each of the four or more parts of the volume of waste is obtained by a method comprising: providing a simulation, the simulation having an equivalent volume as the volume of waste, the simulation including a simulation part corresponding to each of the four or more parts of the volume of waste, the equivalent volume of the simulation being free of radioactive material; providing the simulation in an equivalent monitoring space, with equivalent detectors, to those used for the volume of waste; dividing one or more of the simulation parts into two or more volumes which are equal to give two or more equal volumes; providing a known activity radioactive source at one or more positions in more than one of the equal volumes of one of the simulation parts provided by the simulation; and determining a detector response for one or more of the detectors to the known activity source in one of the one or more positions, a comparison of the detector response and known activity contributing to an equal volume correction function for that equal volume, one or more such equal volume correction functions providing the separate correction factor for the part.