THUDosePD:a three-dimensional Monte Carlo platform for phantom dose assessment

Monte Carlo simulations are frequently utilized in radiation dose assessments.However,many researchers find the prevailing computing platforms to be intricate.This highlights a pressing need for a specialized framework for phantom dose evalua-tion.To address this gap,we developed a user-friendly radiation dose assessment platform using the Monte Carlo toolkit,Geant4.The Tsinghua University Phantom Dose(THUDosePD)augments the flexibility of Monte Carlo simulations in dosi-metric research.Originating from THUDose,a code with generic,functional,and application layers,THUDosePD focuses predominantly on anatomical phantom dose assessment.Additionally,it enables medical exposure simulation,intricate geometry creation,and supports both three-dimensional radiation dose analysis and phantom format transformations.The system operates on a multi-threaded parallel CPU architecture,with some modules enhanced for GPU parallel computing.Benchmark tests on the ICRP reference male illustrated the capabilities of THUDosePD in phantom dose assessment,covering the effective dose,three-dimensional dose distribution,and three-dimensional organ dose.We also conducted a voxelization conversion on the polygon mesh phantom,demonstrating the method’s efficiency and consistency.Extended applications based on THUDosePD further underline its broad adaptability.This intuitive,three-dimensional platform stands out as a valuable tool for phantom radiation dosimetry research.

Calculations of Radiations Attenuation and Dose Assessments of Tunnels Passing under Water Canals

Most of the developed countries have used their tunnels as protective structures （public nuclear shelters） in case of nuclear emergencies to protect their citizens from the dangerous effects of nuclear weapons. The research aims to explain how to use tunnels to protect some people from neutrons and gamma rays and account the required safe depth. The computer code （MCNP5） is used at this model for such tunnel to account attenuation of both neutrons and gamma rays passing through the canal water, sand, soil and reinforced concrete wall layers. The last one （thickness 105 cm） constructed the tunnel construction. Also, the computer code is used to account the dose inside the tunnel, and account （neutron） dose, （neutron, gamma） dose, prompt （gamma） dose, total （gamma） dose and total （neutron ＋ gamma） dose estimated by μsv/h, at different depths from the water surface level （depths 200 cm, 500 cm, 1,000 cm, 1,600 cm, 2,200 cm, 2,600 cm, 2,800 cm, 3,400 cm, 3,700 cm, 4,000 cm and 4,600 cm）. Then, account these doses for three bombs （its intensity 20 KT, 100 KT and 1,000 KT）.

SRDAAR－QNPP：a computer code system for the real－time dose assessment of an accident release for Qinshan Nuclear Power Plant

The paper presents a computer code system 'SRDAAR- QNPP' for the real-time dose as-sessment of an accident release for Qinshan Nuclear Power Plant. It includes three parts:thereal-time data acquisition system, assessment computer. and the assessment operating code system. InSRDAAR-QNPP, the wind field of the surface and the lower levels are determined hourly by using amass consistent three-dimension diasnosis model with the topographic following coordinate system.A Lagrangin Puff model under changing meteorological condition is adopted for atmosphericdispersion, the correction for dry and wet depositions. physical decay and partial plume penetrationof the top inversion and the deviation of plume axis caused by complex terrain have been taken in-to account. The calculation domain areas include three square grid areas with the sideline 10 km, 40krn and 160 km and a grid interval 0.5 km, 2.0 km, 8.0 km respectively. Three exposure pathwaysare taken into account:the external exposure from immersion cloud and passing puff, the internalexposure from inhalation and the external exposure from contaminated ground. This system is ableto provide the results of concentration and dose distributions within 10 minutes after the data havebeen inputed.

Estimation of exposure dose for decontamination workers from contaminated soil at a nuclear decommissioning site in Korea

Assessment of the exposure dose for workers is crucial to protecting workers from the radiological risk.This preliminary study estimates the potential radiological exposure for a soil remediation worker at a nuclear decommissioning site contaminated with Cs-137 in Korea,and then calculates the maximum workable soil concentration to comply with the occupational dose constraint of 20 mSv per year.The Korean characteristic data,detailed exposure scenarios for workers by the type of work,and relevant exposure pathways were used in the dose estimation.As a result,the most severe exposure-induced work type was identified as the excavator operation with an annual individual dose of 5.92×10^-5 mSv for a unit concentration of soil,from which the derived maximum workable soil concentration was 3.38×105 Bq/kg.Furthermore,dose contribution by each exposure pathway was found to be decreased in the following order:external radiation exposure,soil ingestion,dust inhalation,and skin contamination.The results of this study are expected to be used effectively to optimize radiation protection for workers and establish appropriate work procedures for future site remediation.

Dose Monitoring of Pulse Neutron on HL-2A Tokamak

From Sep. 3 of 2005 to Oct. 26, the HL-2A tokamak experiment carded out 42 days discharge operation, and successfully completed many experiments. These experiments include divertor operation, high density, molecular beam injection, LHCD, siliconizafion. Experimental results create new records. The parameters achieved in that year were as follows： plasma current Ip = 320 kA, toroidal magnetic field BT=2.2 T, plasma density ne = 4.2×10^19 m^-3, plasma exist time tp = 1580 ms, plasma current plateau time is 1200 ms, electron temperature is 900 eV, ion temperature is 800 eV. To protect worker and public and assess neutron radiation level, we monitored neutron dose in radiation controlled area by the pulse neutron dose monitoring system, which was made by institude of high energy physics, chinese academy of sciences and southwestern institute of physics, china nation nuclear corporation （ CNNC ）.

Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

The specific absorbed fractions（SAF） for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human（CVH） data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 ke V to 4 Me V energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females.