Simulation Calculation And Protection Research Of Air Gamma Radiation Dose Rate In Storage Network Containing Tail

Thorium is a potential nuclear energy resource with important national strategic significance.This paper proposes to use the storage method to store the tailings containing slag produced by rare earth refining.Through small tail slag placement experiments the experimental data is measured by different instruments and the composition and water content of the slag are sampled and analyzed.MCNP5 establishes a mathematical model of the repository to study the effects of different factors such as water content density specific activity on the air gamma radiation dose rate and compares with the actual measurement data to correct the experiment.Based on the simulation experiment of the small tailings bucket the large Monte Carlo simulation calculation is carried out on the whole tailings storage and finally the air ? absorbed dose rate in the storage of the tailings storage reservoir is obtained and the individual of the staff is calculated.Absorb the dose and finally propose radiation protection measures.Finally the following research results were obtained:(1)The decay balance relationship of the radioactive elements of radioactive elements in the slag is analyzed and the uranium and lanthanides in the radioactive elements are grouped according to the decay time and the lanthanides are divided into Th-A Th-B and Th.In the-C group the uranium system is divided into three groups UA UB and UC.In order to reduce the unnecessary workload through simulation Directed by Li Xiangyang calculation the air ? absorbed dose rate of Th-A U-A and U-C can be ignored in the calculation process.(2)Through the simulation calculation the error between the simulated value and the actual measured value of the air ? absorbed dose rate around the four barrels containing the tailings slag is kept within 15% which proves that the air ? absorbed dose rate of the MCNP5 simulated tail slag reservoir is feasible.(3)Analyzed the influence of the error caused by the measurement of element mass ratio in the simulation process.The results show that the simulation errors caused by the measurement errors of five elements such as Ce La Nd Pb U and Zr are all within 3%.The Th element simulation error is relatively high but it is also within 5%.Therefore the x-fluorescence method for measuring the mass fraction of the slag element has almost no effect on the simulation results.(4)Constructing the numerical simulation of the Li repository establishing the MCNP model of the repository and simulating the air gamma absorption dose rate of the reservoir full slag and unfilled slag and proposing radiation protection measures.