Multilayer Shielding Design for Intermediate Radioactive Waste Storage Drums: A Comparative Study between FLUKA and QAD-CGA

Wenqian Li,Yilin Huang,Xuegang Liu,Ming Li,Sheng Fang

doi:10.1155/2019/8186798

Abstract

To ensure that the outside dose rate of waste package is below the limitation of national laws and regulations, based on the standard 200L drum, a new drum with inner shielding was proposed for intermediate-level radioactive waste (ILW) storage. For comparison, FLUKA and QAD-CGA were used to verify the shielding design of the ILW storage drums produced in INET with multiple inner shielding layers. The flux and dose were calculated and analyzed for four different cases. In QAD-CGA calculation, it was found that different buildup factors can lead to the considerably different results. A weighted algorithm was proposed to correct QAD-CGA for multilayer shielding cases. In FLUKA calculation, parameter optimization and tailored variance reduction technique (VRT) were used. Quantitative efficiency evaluation of different FLUKA settings using the FOM factor was carried out. The differences in the calculated dose rates results between the FLUKA and QAD-CGA programs are within one order of magnitude. The results of QAD-CGA are generally higher than those of FLUKA. The analysis shows that appropriate corrections in QAD-CGA can make the trend of the calculation results more consistent with the theory. In FLUKA calculation, with optimized setting and VRT adopted, the calculation efficiency can be improved more than 20 times. The results of this study provide not only suggestions for the design of the ILW storage drums but also useful references for other similar work.

Highlights

While the nuclear power brings comfort and convenience to people’s lives, it produces radioactive waste inevitably
Two detectors were set at the top and side of the intermediate-level radioactive waste (ILW) storage drums, respectively
The FLUKA and QAD-CGA programs were used for the shielding calculation of the ILW storage drums which are manufactured in the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University

Summary

Introduction

While the nuclear power brings comfort and convenience to people’s lives, it produces radioactive waste inevitably. With the development of nuclear power and corresponding nuclear fuel cycle, the menace of radioactive waste has become increasingly prominent. At the end of 2010, the total volume of the low and intermediate-level radioactive waste (LILW) from nuclear power plants (NPPs) in China was about 10,000 cubic meters [1]. The NPPs in China generate about 2,000 cubic meters of LILW per year. It is estimated that by 2020, the accumulation of these radioactive waste will reach 30,000 cubic meters [2]. Minimization of radioactive waste is one of the basic principles of radioactive waste management, which requires thorough and comprehensive considerations during the design to reduce the volume of radioactive waste as low as reasonably achievable (ALARA) [3, 4]

Results

Discussion

Conclusion