Of Industrial Water Row Mouth ¦Ã Continuous Monitoring System Calibration Factor Calculated

In 1990's, A system used in continuously monitoring and controlingγ-radioactivity in Industrial Drainage was built in CIAE. From then on, it hadmonitored more than 40 times abnormal releases of induatrial drainage containingradioactive water, which was about 4800 m³ water in all. The system doesefficiently protect the abnormal release of Industrial Drainage fromenvironmental pollution, ensure the controllable release of Industrial Drainage,and protect the ambient environment of CIAE. Because of the difficulty incalibration and nuclide analysis, the system can not be widely applied in nuclearfacilities, it's original function is restricted. In this research, the Monte CarloLibrary Least Squares methods(MCLLS) is thought to be the best way to solvesuch problem. The detector response functions(DRFs), which are the fundamentalin MCLLS, became the major content in this research.There are two methods to estabilish the DRFs, Numeric method and MonteCarlo method, which are compared in detail in this research. Numeric method iseffective with simple geometry and it can't deal with physical mechanismcorrectly, but Monte Carlo method can not only deal with physical mechanism indetail, but also deal with arbitrary 3-Dimension geometry, so Monte Carlomethod is chosen to estabilish DRFs in this research.The DRFs accuracy is depended on the equivalent calculation model of thedetector. In this research, the sources of ²⁴¹Am, ⁵⁷Co and ¹¹³Sn were used to testthe Gain Stabilization function in Ortec Maestro. As a result, the ¹¹³Sn presentsbetter result than other two sources. MCNP-4C version was used to estabilish thedetector calculation mode, By virtue of the comparison between the calculationdetection efficiency and the experimental detection efficiency, the calculationmodel was iteratively corrected. Eventually, the calculation model wasestabilished. The relative errors between the calculation results and the experiment results are mostly smaller than 5%, only a few greater than 5%.¹³⁷Cs and ⁶⁰Co point sources were used to verify whether the calculationmodel is right. According to the energy calibration and FWHM(Full Width atHalf Maximum) calibration results, MCNP calculation results got a good matchwith experiment results. The whole spectrum detection efficiency of experimentand calculation were used to calculate the whole pool detection efficiencyindividually, the relative error between the experimental result and calculationalresult was small than 5%.The volume source was made by dissolved 5000 gram analytical reagent ofKCl in 1 m³ water, which was 80.15 Bq/l. But the calculational result got a badmatch with the experimental result. There are some comments on this problem.The spectrum analysis software based on Monte Carlo Library Least Squareshas been compiled by cooperated with Professor Liyu Wang, which is thefundamental of nuclide analysis in the system of monitoring and controlingγ-radioactivity in Industrial Drainage.