Radioactive measurement validation method of an used component in nuclear power plant

PURPOSE: A method for confirming the effectiveness of measuring the radioactivity of a large metal device used in a nuclear power plant is provided to compare patterns with respect to radioactivity contamination based on the result of measuring a dosage rate per each spot so that the lattice polluted by an artificial nuclide is sorted. CONSTITUTION: A method for confirming the effectiveness of measuring the radioactivity of a large metal device used in a nuclear power plant is as follows. If the pollutant concentration of an artificial nuclide is less than a minimum detectable activity of a representative sample analysis, the gross radioactivity of the natural nuclide which is measured by the representative sample analysis is evaluated based on a dosage rate of a measurement object and compared by using a proportional expression in which proportion of the gross radioactivity of the natural nuclide, a dosage rate measured by a normal lattice, and a non-radioactivity of the artificial nuclide are steady (S120) so that the effectiveness of the representative sample analysis and the representative of a sample are proven. [Reference numerals] (AA) Increase the number of a partition lattice (Double); (S10) Define a lattice group; (S100) Reference lattice=final lattice; (S110) Increase the dosage rate of the radiation only; (S120) Secondarily calculate the gross radioactivity of the natural nuclide by using the dosage rate of the radiation; (S130) Set a reference lattice of a lattice having the highest dosage rate of the radiation; (S20) Determine the number or the size of partition lattices; (S30) Arrange TLD element (Measure a dosage rate of radiation); (S40) Collect a sample and measure non-radioactivity; (S50,S90) Artificial nuclide; (S60) Calculate the non-radioactivity; (S70) Calculate the gross radioactivity of a natural nuclide by using a representative sample; (S80) Re-measure after changing a reference lattice; (S85) Primarily calculate the gross radioactivity of the natural nuclide by using a representative sample analysis