Study On The Scale Model Of Efficiency Matrix Of Tomographic Gamma Scanning

Some nuclear waste will be produced inevitably in the production, transportation, storage, and use of the nuclear material. Before the final treatment, the quantity of different nuclides in the waste must be confirmed to check up whether the conditions of the storage are satisfied and to make corresponding plan to treat the waste.Because the density and the distribution of the waste are every uneven in the waste drum, the Non-Destructive-Assay is adaptive to measure the waste. Tomographic Gamma Scanning is one of the advanced Non-Destructive-Assay methods. Tomographic Gamma Scanning can accurately measure the activity of the waste without physical or chemical changes of the waste, and adapts to the waste with middle or high density. Some domestic scholars do some research on Tomographic Gamma Scanning, but have not accomplish the practical application of this technology. Some more researches are needed.The paper focuses on the efficiency matrix, one of the pivotal technologies. Because Tomographic Gamma Scanning's efficiency matrix is big and attenuation must be ignored when the matrix is scaled, traditional experimental methods don't adapt to this situation, especially when radio-source is a bulk. By analyzing the factors which influence the matrix, find out the independent matrix elements. Instead of the numerous experimental scale, the program MCNP is used to simulate the experiment to calculate the independent matrix elements. In the simulation, point-source and bulk-source are adopted in the calculation. Compare the results calculated by point and bulk methods, it can be found the error between point and bulk should be considered in this paper's model.When MNCP is used to simulate the model to calculate the efficiency, some accurate parameters of the detector are needed. But because some manufactures keep some parameters secret and some parameters change for wrong maintenance, some errors will...