The Analysis Of Nuclear Instrument Radiation Dose And Radiation Workers Exposure Dose In Ansteel Smelting System

Objective: To understand and master the protection status nuclear instrumentation andradiation workers exposure dose in Ansteel smelting system, clear smelting system varioustypes of nuclear instrumentation impact of exposure doses in radiation workers, and providetechnical support for enterprises radiation management.Methods: Take105units of nuclear instrumentation and179radiation workers in Ansteelsmelting system as research object, analyse the protection of nuclear instrumentation and theexposure dose of radiation workers; According to GBZ125-2009, this study used6150ADradiometer and190N neutron dosimeters monitoring radiation dose rate; According toGBZ128-2002, this study used personal dosimeters TLD-III and BR2000D-III reader forpersonal dose monitoring; Count data uses the constituent ratio, and the comparison ofmeasurement data use comparison rank sum test. This study used SPSS software to analyzestatistical data.Results：1There are105units of nuclear instrumentation in Ansteel smelting system. Nuclearinstrumentation distribution type shows that the number of the nuclear scales (48%) andmoisture meters (35%) are more than other typies. The radionuclide distribution of nuclearinstrumentation shows that the numbers of137Cs are more than other radionuclides.2There are179radiation workers in Ansteel smelting system. The numbers of Blastfurnace feedstock workers (34%) are more than other other types of work, followed by theworkers of continuous casting to see fire and sintering ingredients workers. Blast furnace rawmaterials workers and blast furnace contact point inspection workers are expoured to gammaray and neutron mixed off-site, and the rest of the trades are only exposured to gamma-rayexternal irradiation.3Ironmaking nuclear instrumentation monitoring results show that the monitoring resultsof the neutron moisture meter dose equivalent rate are significantly greater than that others;Steelmaking process nuclear instrumentation monitoring results show that when replacing mold platform，bare source rod and level gauge in the leadtank monitoring results are muchgreater than other types in smelting system.4After rank-sum test, alone nuclear scale nuclear scales radiation dose rates aresignificantly greater than the moisture meter one, the blast moisture meters are significantlygreater than the belt moisture analyzer.5Comparison of similar nuclear instrumentations with different activities, the results showthat the radiation dose rates are not all with the activity increased.6According to estimates, the annual effective dose of the various types of work in AnSteelsmelting system are between in0.01mSv/a~0.74mSv/a, the doses are below constraintvalue of the annual dose limit7Personal dose monitoring results indicate that, the sintering ingredients workers annualeffective dose range0.41mSv~1.01mSv, average dose0.25mSv; the worker of continuouscasting to see fire annual effective dose range0.26mSv~2.83mSv, average dose0.51mSv;continuous casting point inspector annual effective dose range0.10mSv~0.40mSv, averagedose0.24mSv; annual effective dose of the three trades personnel are much lower than theoccupational groups individual dose constraint value.8The results of the personal dose monitoring are much lower than the estimates.Conclusion:1In normal production state, the radiation dose rate of the nuclear instrumentation inAnsteel accords with radiation hygiene standard.2The radiation dose rate of the continuous casting level gauge is significantly greater andmore dangerous than other types of nuclear instrumentation of smelting system.3Affected by the protection status, the radiation dose rates of similar nuclearinstrumentation are not all with the activity increased.4According to the radiation dose rate and work time, the estimated annual effective dosesof the three types of workers（sintering ingredients workers, the worker of continuous castingto see fire, continuous casting point inspector） are significantly higher than other workers.The annual effective doses of dose estimation and personal dose monitoring are all lower thanthe occupational group individual dose constraint value.5The estimates dose is higher than personal dose monitoring results, but there is asimilarity between personal dose monitoring and the dose estimates in the distribution trend. 6The research results show that level gauge and three types of workers (sinteringingredients workers, the worker of continuous casting to see fire, continuous casting pointinspector) are the focus of the management of the radiation protection in Ansteel smeltingsystem.