PURPOSE: To enable whether the contamination mode of a radioactive waste is of a surface contaminant or of a radioactive matter to be accurately discriminated by comparing a difference between the ratios of measured β ray values to measured γ ray values obtained by measuring objects to be measured by radiation measuring means with a reference value.
CONSTITUTION: β rays and γ rays radiated from an object to be measured 1 being conveyed by a conveyor line 7 are measured by β ray detectors 4aW4d and γ ray detectors 5aW5b on radiation detecting means 2aW2d, respectively. Then, measured results are fed to arithmetic means 3 and the ratios of measured βby values to measured γ ray values for every measuring means 2aW2d are calculated. A difference between the ratios obtained by two pairs of the means (2a and 2b) and (2c and 2d) respectively opposing to each other is calculated and compared with a reference value. The object to be measured can be accurately judged to be a surface contamination when the absolute value of the difference is larger than the reference value while it is judged as a radioactive matter when the value is not larger than the reference value.
YODA MASAKI
GOTO TETSUO
KATO HIROAKI
TOSHIBA CORP
| JPS61161481A | 1986-07-22 |
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