The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase...The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase the production capacity. This paper proposes a proprietary vacuum dry-bag isostatic pressing(DIP) apparatus. The structural change of the matrix graphite powder during the DIP process was examined by analyzing the density change of the matrix graphite spheres with pressure. The soft molding process was simulated using the finite element method. The dimensional changes in the spheres during the pressing, carbonization, and purification stages were explored. The performance of the fuel matrix produced by the DIP method was comprehensively examined. The fuel matrix met the technical requirements and its anisotropy was significantly reduced. The DIP method can significantly improve both the production efficiency and quality of fuel elements. This will play a key role in meeting the huge demand for fuel elements of HTRs and molten salt reactors.展开更多
The HTR Fuel Element R & D Program,set in 1987,aims to develop the manufacturetechnology of HTR fuel element and to produce the fuel element for the first core of our 10MW experimental reactor.Now the work on labo...The HTR Fuel Element R & D Program,set in 1987,aims to develop the manufacturetechnology of HTR fuel element and to produce the fuel element for the first core of our 10MW experimental reactor.Now the work on laboratory scale is phased out.In this paper,the fuel element manufacture technology is described and the test results are given.展开更多
Discontinuous deformation analysis （DDA） method is a newly developed discrete element method which employs the implicit time-integration scheme to solve the governing equations and the open-close iteration （OCI） m...Discontinuous deformation analysis （DDA） method is a newly developed discrete element method which employs the implicit time-integration scheme to solve the governing equations and the open-close iteration （OCI） method to deal with contact prob- lem, its computational efficiency is relatively low. However, spherical element based discontinuous deformation analysis （SDDA）, which uses very simple contact type like point-to-point contact, has higher calculation speed. In the framework of SDDA, this paper presents a very simple contact calculation approach by removing the OCI scheme and by adopting the maximal displacement increment （MDI）. Through some verification examples, it is proved that the proposed method is correct and effective, and a higher computational efficiency is obtained.展开更多
基金supported by the National S&T Major Project (No.ZX06901)。
文摘The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase the production capacity. This paper proposes a proprietary vacuum dry-bag isostatic pressing(DIP) apparatus. The structural change of the matrix graphite powder during the DIP process was examined by analyzing the density change of the matrix graphite spheres with pressure. The soft molding process was simulated using the finite element method. The dimensional changes in the spheres during the pressing, carbonization, and purification stages were explored. The performance of the fuel matrix produced by the DIP method was comprehensively examined. The fuel matrix met the technical requirements and its anisotropy was significantly reduced. The DIP method can significantly improve both the production efficiency and quality of fuel elements. This will play a key role in meeting the huge demand for fuel elements of HTRs and molten salt reactors.
基金the High Technology Research and Development Programme of china
文摘The HTR Fuel Element R & D Program,set in 1987,aims to develop the manufacturetechnology of HTR fuel element and to produce the fuel element for the first core of our 10MW experimental reactor.Now the work on laboratory scale is phased out.In this paper,the fuel element manufacture technology is described and the test results are given.
基金supported by the National Basic Research Program of China("973" Project)(Grant Nos.2014CB046904&2014CB047101)the National Natural Science Foundation of China(Grant Nos.51479191&51509242)
文摘Discontinuous deformation analysis （DDA） method is a newly developed discrete element method which employs the implicit time-integration scheme to solve the governing equations and the open-close iteration （OCI） method to deal with contact prob- lem, its computational efficiency is relatively low. However, spherical element based discontinuous deformation analysis （SDDA）, which uses very simple contact type like point-to-point contact, has higher calculation speed. In the framework of SDDA, this paper presents a very simple contact calculation approach by removing the OCI scheme and by adopting the maximal displacement increment （MDI）. Through some verification examples, it is proved that the proposed method is correct and effective, and a higher computational efficiency is obtained.
