RADIATION PROTECTION ›› 2024, Vol. 44 ›› Issue (4): 349-355.

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Discussion on key technologies of portable on-line monitoring equipment for low-level radioactive waste water in NPPs

ZHOU Jianwang, YOU Chengmao, MEI Xiangjie, ZHOU Kebo, ZHANG Sujie, YIN Wangming   

  1. Daya Bay Nuclear Power Operations and Management Co. Ltd., Guangdong Shenzhen 518124
  • Received:2023-03-03 Online:2024-07-20 Published:2024-08-05

Abstract: Based on the situation and demand of a NPP, the features of LLRW are summarized. The technical requirements for portable online radioactive monitoring equipment are specified. The most important requirement is to meet the low detection limit (minimum detectable activity concentration, MDAC≤8 Bq/L) and portability of the equipment (total weight of the equipment should be≤50 kg). Key technologies such as measurement mode, detector selection and calibration method are then discussed. The measurement mode is generally sampling mode. The detector is generally large volume NaI crystal. The calibration methods are usually standard liquid source method and representative point method. Finally, the current online monitoring equipment for LLRW is investigated. It is found that the weights of all the existing equipment are more than 200 kg, which is far from the requirement of NPPs. Therefore, it is necessary to develop new on-line monitoring equipment with low MDAC and excellent portability. Three research directions are suggested, which are the application of new detector types, the development of new detector structure, and the development of new measurement methods. In order to improve the detection efficiency, a new detector structure based on annular NaI crystal is proposed. The weight of the new equipment and the MDAC is discussed preliminarily. It is expected to meet the requirements of NPPs.

Key words: nuclear power plant, low-level radioactive waste water, on-line monitoring equipment, portable

CLC Number: 

  • TL812