Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (12): 120603-120603.doi: 10.11889/j.0253-3219.2018.hjs.41.120603

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles    

On-site monitoring the activity concentration of nuclide 58Co in coolant during PWR oxygenation shutdown

XIA Sanqiang1, LIU Liye1, CAO Qinjian1, HU Ling2, LI Gang2, ZHENG Minggui2, HU Zhibin3   

  1. 1 China Institute for Radiation Protection, Taiyuan 030006, China;
    2 Fujian Fuqing Nuclear Power, Fuqing 350300, China;
    3 China University of Geosciences, Wuhan 430074, China
  • Received:2018-08-21 Revised:2018-10-23 Online:2018-12-10 Published:2018-12-13
  • Supported by:
    Supported by National Natural Science Foundation of China (No.11605162)

Abstract: [Background] During the oxidation operation of a reactor, the max active concentration of 58Co in the coolant and the time to the end of the oxidation operation (activity concentration <25 GBq·t-1) are compulsory. The current chemical sampling method produces large amounts of radioactive waste liquid.[Purpose] This study aims to reduce the current radioactive waste liquid by establishing an external γ spectrum monitoring system.[Methods] The HPGe γ measurement system is used to measure the γ spectrum of the coolant outside the pipeline. The net count rates of the 58Co characteristic peak varition with time were obtained after reactor shutdown. These data can be used to predict the time to reach the maximum active concentration of 58Co in the coolant and the time to reach the end of the oxidation operation, and then performed a sample analysis.[Results] During the oxidation operation of a nuclear power plant, this monitoring system was used to continuously measure the γ spectrum outside the pipeline. The time of the maximum activity concentration of 58Co was predicted to be 33 h and 39 min after shutdown, and the oxidation operation end time predicted to be 57 h after shutdown. By continuously coolant sampling data, the time of the maximum activity concentration of 58Co was 33 h and 34 min after shutdown, and the oxidation operation end time was 57 h and 9 min after shutdown. Two time errors are in normal range (less than 10 min).[Conclusions] The external monitoring method can reduce the sampling frequency significantly and reduce the amount of radioactive waste generated by sampling analysis.

Key words: Oxidation operation, The activity concentration of 58Co, In situ gamma measurement, Chemical sampling

CLC Number: 

  • TL814