Radiation shielding design strategies for lunar minimal functionality habitability element

The QAD program, based on the point kernel integration method, is widely used in the radiation shielding design of nuclear power plants and related fields. However, QAD-CGA, as the latest version of QAD program, still has some problems, which may affect calculation results and limit the application range. In this paper, the features, principles, and algorithms of QAD-CGA program will be described and several optimization will be introduced. The quantity of γ rays considered in each calculation has been expanded, which can supply more accurate results than those from the original program. Furthermore, the number of dose receivers has been increased, which can provide detailed distribution of the dose field. In addition, a method has been put forward to realize the discretization of source intensity automatically which can simplify the input of the program. Meanwhile, the compartmentalization of the discrete source in the program has been improved. If the size of the discrete source can be minimized small enough to be served as an ideological core, the accuracy of calculations of QAD-CGA program would be guaranteed. However, with the increase of the radius of a sphere or cylinder, the volume of the discrete source will be enlarged and the precondition “small enough” will be lost gradually which can result in the increase of the inaccuracy of calculations. A superior algorithm to solve the coordinate distribution of point kernel which is nonuniform has been proposed. It can reduce the inaccuracy from the discretization of the source intensity in spherical and cylindrical geometry effectively. The optimization of QAD-CGA program has been implemented, analyzed and compared to the original edition with a numerical example.

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Primary Shielding Design and Analysis for CLEAR-I

Volume 1: Plant Operations, Maintenance, Engineering, Modifications, Life Cycle and Balance of Plant; Nuclear Fuel and Materials; Radiation Protection and Nuclear Technology Applications ◽

10.1115/icone21-15995 ◽

2013 ◽

Author(s):

Qi Yang ◽

Bin Li ◽

Chao Chen ◽

Minghuang Wang ◽

Qin Zeng

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Research Reactor ◽

Natural Circulation ◽

Radiation Shielding ◽

Lead Alloy ◽

Reactor Plant ◽

Calculation System ◽

Shielding Design ◽

Dual Models

The China Lead-Alloy Cooled Research Reactor (CLEAR-I) is critical/sub-critical dual-models natural circulation lead alloy cooled reactor. This study is to focus on the concern radiation shielding design and analysis for CLEAR-I. The modeling program MCAM and calculation system VisualBUS developed by FDS Team was used based on Monte Carlo method and other coupled methods. As indicated by the results, the dose rate in the reactor plant (outside the containing compartment above the reactor) was below 9 uSv/h during operation and less than 1 uSv/h during shutdown, meeting with the requirements of shielding.

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Rationalization of Radiation Shielding Design for Spent Nuclear Fuel Storage Building

Volume 2: Fuel Cycle and High Level Waste Management; Computational Fluid Dynamics, Neutronics Methods and Coupled Codes; Student Paper Competition ◽

10.1115/icone16-48332 ◽

2008 ◽

Author(s):

Yuji Nemoto ◽

Toshihisa Tsukiyama ◽

Shigeki Nemezawa ◽

Hideo Nakano

Keyword(s):

Nuclear Fuel ◽

Seismic Design ◽

Scattered Radiation ◽

Spent Nuclear Fuel ◽

Heat Removal ◽

Radiation Shielding ◽

Air Supply ◽

Exhaust Duct ◽

Fuel Storage ◽

Shielding Design

A spent nuclear fuel storage building is generally a structure provided with heat removal, radiation shielding functions, and a seismic design. The facility has air supply ducts and a chimney exhaust duct for removing heat through natural cooling, with the structural shapes determined by the demands of the above functions. In radiation protection design, radiation levels must be kept below acceptable levels for the general public. The radiation dose can be lowered by increasing the concrete thickness, as typically applied in radiation shielding design, or by increasing the distance. The setting of additional shielding plates also helps reduce the scattered radiation escaping from the air supply and exhaust ducts. However, such protective structures against the scattered radiation challenges in effective heat removal and seismic design. Therefore, determining a building structure that can satisfy all safety demands requires a great deal of time. This study aims to effectively achieve radiation shielding. The height and width of the exhaust duct were considered, and the correlation of these parameters was studied. In the calculation, two-dimensional Sn code (DORT) was used to examine the validity of the results. Monte Carlo N-Particle Transport Code (MCNP) calculations were also made for comparison with the DORT results. The cross-section libraries of JENDL3.3 and DLC23F were used in this calculation, with the difference being clarified.

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