Application research of high purity germanium (HPGe) gamma-ray spectrometer in nuclear pollution of import and export aquatic products
【Objective】The method of detecting radionuclide in aquatic products using high purity germanium(HPGe)gamma-ray spectrometer was established to monitor nuclear pollution situation of Shandong import and export aquatic goods and estimate the influence of Fukushima nuclear accident on aquatic products safety in our country. 【Method】The samples were rinsed, dried in the air centering on the edible parts, crushed, packaged and finally detected by HPGe gamma-ray spectrometer. Three positive samples of137Cs were randomly chosen to make into three parallel classes and detected for 0.5, 1,2,4,6,8,12,18,36 and 48 h, respectively. The altas was analyzed using DSA-1000 digital spectrometer and Genie 2000 software. Specific activity of nuclide in the samples at different time was obtained. 【Result】When the detection time was 6 h, the detection results went up gradually as time went by and tended to be stable after 8 h. Among1127 samples, the detection rate was 8.9%. The radionuclide was mainly134Cs,137Cs and110 mAg in positive samples, in which detection rate was 6.21%, 5.15% and 2.75%. The highest specific activity value of137Cs and134Cs was 27.8 Bq/kg and 16.7 Bq/kg, respectively. The specific activity value of134Cs,137Cs and110 mAg in the tested positive samples was far below the standard in different countries. 【Conclusion】The optimum detection time was 6-8 h. After Fukushima nuclear accident, no severe pollution happened to import and export aquatic products in China, but it still needed to be monitored.