Session: 09-04: Radiation shielding

Paper Number: 132332

132332 - Development of an Integrated Point Kernel Shielding Calculation Code for Fast Three-Dimensional Radiation Field Characterization 

Abstract: 

Shielding design and radiation safety analysis demand the handling of systems with intricate sources and geometries. The efficacy of a shielding calculation heavily relies on a detailed and efficient code. Conventional deterministic or stochastic methods often lack efficiency when addressing large-scale, complex geometry scenarios. The point kernel method, known for its fast calculation and efficacy in solving deep penetration problems, is commonly applied in three-dimensional radiation field calculations.

A new integrated point kernel shielding code has been developed by the Institute of Nuclear and New Energy Technology (INET) for the rapid characterization of three-dimensional radiation fields. The code's extensive database includes photon interaction cross-sections for 92 elements and G-P parameters for 22 elements sourced from the XCOM database and ANSI-1991 report respectively, covering essential data for shielding calculations. The integration of the point kernel technique, Construct Solid Geometry (CSG) modeling method, G-P fitting, and various multilayer build-up factor (MLBUF) formulas enhances the code's versatility.

The CSG method facilitates entity definition through Boolean functions of pre-defined surfaces, written in XML format. The parameterized modeling process enables the swift establishment of large-scale scenarios and efficient implementation of ray tracing. Appropriate formulas, such as Harima’s method and Broder’s method, are employed for equivalent atomic numbers and MLBUFs, respectively.

Moreover, the code's verification and validation (V&V) have been carried out by benchmark problems available in the literature. The code is validated by estimating BUFs, MLBUFs, and gamma dose rates at the exit of the shield with Monte Carlo simulation. The calculation result and efficiency of the two methods are herein investigated. The point kernel code achieves acceptable accuracy and shorter calculation time than the Monte Carlo method.

To address the deep penetration problem, which is inherent in exact nuclear industry shielding calculations, the code's extensivity is verified by comparing results with OpenMC and QAD-CGA for complex shielding geometries of up to 100 mean free paths (MFPs). The outcomes demonstrate the accuracy and efficiency of the code's deep penetration calculation capabilities for complex geometry arrangements.

The engineering use efficiency of the code is assessed by implementing it in actual plant scenarios. The analysis identifies radiation field characteristics of the High-Temperature Gas-Cooled Reactor (HTGR). A large-scale HTGR plant model is established, volumetric source terms are defined, and radiation distribution is visualized by dividing the space into response points with structural meshes. The paper concludes with advisory suggestions on radiation safety and personnel health protection, offering valuable references for radiation protection in specific nuclear facilities. The code, developed in C++, is compatible with MacOS, Windows, and Linux operating systems.

Presenting Author: Junyi Chen Institute of Nuclear and New Energy Technology, Tsinghua University

Presenting Author Biography: Chen Junyi is a doctoral candidate at the Institute of Nuclear and New Energy Technology at Tsinghua University, currently pursuing research under the guidance of Professor Liang Jingang. His research focuses on the computational study of high-temperature gas-cooled reactor shielding based on particle transport and other innovative methods.

As a doctoral student, Chen Junyi looks forward to sharing his research findings and insights with the global academic community. He is enthusiastic about participating in academic forums such as conferences and welcomes opportunities for collaboration and knowledge exchange with fellow researchers and professionals in the field.

Authors:

Junyi Chen Institute of Nuclear and New Energy Technology, Tsinghua University
Ruihan Li Institute of Nuclear and New Energy Technology, Tsinghua University
Jingang Liang Institute of Nuclear and New Energy Technology, Tsinghua University