Korean-specific internal dosimetry data for radioiodine bioassay and evaluation of the dosimetric impact

Tae-Eun Kwon,Yoonsun Chung,Choonsik Lee Korean Nuclear Society 2025 Nuclear Engineering and Technology Vol.57 No.3

Our earlier works focused on exploring the Korean iodine biokinetic model and calculating Korean-specific S values and dose coefficients. Building on this foundation, this study extended our efforts to establish an extensive dosimetry dataset for Korean-specific iodine bioassay. We calculated bioassay functions (e.g., thyroid retention and urinary excretion functions), dose-per-content-functions, and content for the specified doses based on the Korean biokinetic model and dose coefficients previously developed. Also, this study provides a comprehensive understanding of the practical impact of using Korean-specific dosimetry data. Compared to the ICRP reference data, the thyroid retention functions for Koreans were significantly lower (for I-131, peaks at 18 % vs. 27 %). The physical half-lives of radioiodine played a significant role in the differences of dose-per-content-function. For long-lived iodine isotopes such as I-125, the dose-per-content-functions were comparable to ICRP data, whereas for short-lived iodine isotopes such as I-131, the higher values were observed in the Korean data, indicating a greater dose estimation for a given iodine activity measured in the thyroid. Although we revealed the differences between Korean and ICRP reference data, the comprehensive understanding of Korean data suggests that using the Korean-specific data should be considered only when high doses are predicted.

Simulation study on iodine thyroid blocking in Koreans with high dietary iodine consumption

Tae-Eun Kwon,Yoonsun Chung,Choonsik Lee Korean Nuclear Society 2025 Nuclear Engineering and Technology Vol.57 No.7

This study conducted a simulation of iodine thyroid blocking in the Korean population, which typically has a high dietary iodine intake, using the Korean biokinetic model. We evaluated the thyroid protective effects of stable iodine administration and produced thyroid retention functions and dose coefficients for Koreans. Our findings highlight notable differences between the Korean model and the International Commission on Radiological Protection (ICRP) reference model. The faster recovery from the thyroid blocking, due to higher blood iodide concentrations, resulted in lower protective effects (66 % versus 86 % for 100 mg of stable iodine administered 24 h before iodine exposure) compared to the ICRP model. Additionally, the Korean model demonstrated higher thyroid retention functions, particularly when stable iodine was administered within 24 h before or 2 h after exposure, with delayed secondary peaks. Thyroid dose coefficients were also higher in the Korean model, with values up to 1.5 times greater, due to both lower protective effects and higher S values in Korean anatomical models. While this study offers valuable insights into the thyroid blocking effect in Koreans, this study does not undermine the validity of thyroid protection guidelines in Korea, which should be based on broader assessments, including pathological and risk-benefit analyses.

NUCLEAR HUMAN RESOURCE PROJECTION UP TO 2030 IN KOREA

Min, Byung-Joo,Lee, Man-Ki,Nam, Kee-Yung,Jeong, Ki-Ho Korean Nuclear Society 2011 Nuclear Engineering and Technology Vol.43 No.4

The prospects for growth of the nuclear power industry in Korea have improved remarkably as the demand for energy increases in stride with economic development. Meanwhile, as nuclear energy development is enhanced, nuclear technology has also improved evolutionarily and innovatively in the areas of reactor design and safety measures. As nuclear technology development in Korea advances, more human resources are required. Accordingly, the need for a well-managed program of human resource development (HRD) aimed at assuring needed capacities, skills, and knowledge and maintaining valuable human resources through education and training in various nuclear-related fields has been recognized. A well-defined and object-oriented human resource development and management (HRD&M) is to be developed in order to balance between the dynamics of supply and demand of the workforce in the nuclear industry. The HRD&M schemes include a broad base of disciplines, education, sciences, and technologies within a framework of national sustainable development goals, which are generally considered to include economics, environment, and social concerns. In this study, the projection methodology considering a variety of economic, social, and environmental factors was developed. Using the developed methodology, medium- and long-term nuclear human resources projections up to 2030 were conducted in compliance with the national nuclear technology development programmes and plans.

Development of a Traceability Analysis Method Based on Case Grammar for NPP Requirement Documents Written in Korean Language

Yoo Yeong Jae,Seong Poong Hyun,Kim Man Cheol Korean Nuclear Society 2004 Nuclear Engineering and Technology Vol.36 No.4

Software inspection is widely believed to be an effective method for software verification and validation (V&V). However, software inspection is labor-intensive and, since it uses little technology, software inspection is viewed upon as unsuitable for a more technology-oriented development environment. Nevertheless, software inspection is gaining in popularity. KAIST Nuclear I&C and Information Engineering Laboratory (NICIEL) has developed software management and inspection support tools, collectively named "SIS-RT. "SIS-RT is designed to partially automate the software inspection processes. SIS-RT supports the analyses of traceability between a given set of specification documents. To make SIS-RT compatible for documents written in Korean, certain techniques in natural language processing have been studied [9]. Among the techniques considered, case grammar is most suitable for analyses of the Korean language [3]. In this paper, we propose a methodology that uses a case grammar approach to analyze the traceability between documents written in Korean. A discussion regarding some examples of such an analysis will follow.

Reproduction strategy of radiation data with compensation of data loss using a deep learning technique

Cho, Woosung,Kim, Hyeonmin,Kim, Duckhyun,Kim, SongHyun,Kwon, Inyong Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

In nuclear-related facilities, such as nuclear power plants, research reactors, accelerators, and nuclear waste storage sites, radiation detection, and mapping are required to prevent radiation overexposure. Sensor network systems consisting of radiation sensor interfaces and wxireless communication units have become promising tools that can be used for data collection of radiation detection that can in turn be used to draw a radiation map. During data collection, malfunctions in some of the sensors can occasionally occur due to radiation effects, physical damage, network defects, sensor loss, or other reasons. This paper proposes a reproduction strategy for radiation maps using a U-net model to compensate for the loss of radiation detection data. To perform machine learning and verification, 1,561 simulations and 417 measured data of a sensor network were performed. The reproduction results show an accuracy of over 90%. The proposed strategy can offer an effective method that can be used to resolve the data loss problem for conventional sensor network systems and will specifically contribute to making initial responses with preserved data and without the high cost of radiation leak accidents at nuclear facilities.

Path planning in nuclear facility decommissioning: Research status, challenges, and opportunities

Adibeli, Justina Onyinyechukwu,Liu, Yong-kuo,Ayodeji, Abiodun,Awodi, Ngbede Junior Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.11

During nuclear facility decommissioning, workers are continuously exposed to high-level radiation. Hence, adequate path planning is critical to protect workers from unnecessary radiation exposure. This work discusses recent development in radioactive path planning and the algorithms recommended for the task. Specifically, we review the conventional methods for nuclear decommissioning path planning, analyze the techniques utilized in developing algorithms, and enumerate the decision factors that should be considered to optimize path planning algorithms. As a major contribution, we present the quantitative performance comparison of different algorithms utilized in solving path planning problems in nuclear decommissioning and highlight their merits and drawbacks. Also, we discuss techniques and critical consideration necessary for efficient application of robots and robotic path planning algorithms in nuclear facility decommissioning. Moreover, we analyze the influence of obstacles and the environmental/radioactive source dynamics on algorithms' efficiency. Finally, we recommend future research focus and highlight critical improvements required for the existing approaches towards a safer and cost-effective nuclear-decommissioning project.

An inter-comparison between ENDF/B-VIII.0-NECP-Atlas and ENDF/B-VIII.0-NJOY results for criticality safety benchmarks and benchmarks on the reactivity temperature coefficient

Kabach, Ouadie,Chetaine, Abdelouahed,Benchrif, Abdelfettah,Amsil, Hamid Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.8

Since the nuclear data forms a vital component in reactor physics computations, the nuclear community needs processing codes as tools for translating the Evaluated Nuclear Data Files (ENDF) to simulate nuclear-related problems such as an ACE format that is used for MCNP. Errors, inaccuracies or discrepancies in library processing may lead to a calculation that disagrees with the experimentally measured benchmark. This paper provides an overview of the processing and preparation of ENDF/B-VIII.0 incident neutron data with NECP-Atlas and NJOY codes for implementation in the MCNP code. The resulting libraries are statistically inter-compared and tested by conducting benchmark calculations, as the mutualcomparison is a source of strong feedback for further improvements in processing procedures. The database of the benchmark experiments is based on a selection taken from the International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP handbook) and those proposed by Russell D. Mosteller. In general, there is quite good agreement between the NECP-Atlas1.2 and NJOY21^(1.0.0.json) results with no substantial differences, if the correct input parameters are used.

Ammonium uranate hydrate wet reconversion process for the production of nuclear-grade UO₂ powder from uranyl nitrate hexahydrate solution

Byungkuk Lee,Seungchul Yang,Dongyong Kwak,Hyunkwang Jo,Youngwoo Lee,Youngmoon Bae,Jayhyung Lee Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

The existing wet reconversion processes for the recovery of scraps generated in manufacturing of nuclear fuel are complex and require several unit operation steps. In this study, it is attempted to simplify the recovery process of high-quality fuel-grade UO₂ powder. A novel wet reconversion process for uranyl nitrate hexahydrate solution is suggested by using a newly developed pulsed fluidized bed reactor, and the resultant chemical characteristics are evaluated for the intermediate ammonium uranate hydrate product and subsequently converted UO₂ powder, as well as the compliance with nuclear fuel specifications and advantages over existing wet processes. The UO₂ powder obtained by the suggested process improved fuel pellet properties compared to those derived from the existing wet conversion processes. Powder performance tests revealed that the produced UO₂ powder satisfies all specifications required for fuel pellets, including the sintered density, increase in re-sintered density, and grain size. Therefore, the processes described herein can aid realizing a simplified manufacturing process for nuclear-grade UO₂ powders that can be used for nuclear power generation.

A study on DCGL determination and the classification of contaminated areas for preliminary decommission planning of KEPCO-NF nuclear fuel fabrication facility

Cho, Seo-Yeon,Kim, Yong-Soo,Park, Da-Won,Park, Chan-Jun Korean Nuclear Society 2019 Nuclear Engineering and Technology Vol.51 No.8

As a part of the preliminary decommissioning plan of KEPCO-NF fuel fabrication facility, DCGLs of three target radionuclides, ²³⁴U, ²³⁵U, and ²³⁸U, were derived using RESRAD-BUILD code and contaminated areas of the facility were classified based on contamination levels from the derived DCGLs. From code simulations, one-room modeling results showed that the grinding room in building #2 was the most restrictive (DCGL_gross = 10493.01 Bq/㎡). The DCGL_gross results in contaminated areas from one-room modeling were slightly more conservative than three-room modeling. Prior to the code simulation, field survey and measurements conducted by each survey unit. For a conservative approach, the most restrictive DCGL_gross in each survey unit was taken as a reference to classify the contaminated areas of the facility. Accordingly, seven rooms and 37 rooms in the nuclear-fuel buildings were classified as Class 1 and Class 2, respectively. As expected, fuel material handling and processing rooms such as the grinding room, sintering room, compressing room, and powder collecting room were included in the Class 1 area.

Atomistic simulations of defect accumulation and evolution in heavily irradiated titanium for nuclear-powered spacecraft

Guopeng Zhang,Bin Cai,Hai Huang,Xiaoting Yuan,Longjingrui Ma,Jiwei Lin Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

Titanium alloys are expected to become one of the candidate materials for nuclear-powered spacecraft due to their excellent overall performance. Nevertheless, atomistic mechanisms of the defect accumulation and evolution of the materials due to long-term exposure to irradiation remain scarcely understood by far. Here we investigate the heavy irradiation damage in a-titanium with a dose as high as 4.0 canonical displacements per atom (cDPA) using atomistic simulations of Frenkel pair accumulation. Results show that the content of surviving defects increases sharply before 0.04 cDPA and then decreases slowly to stabilize, exhibiting a strong correlation with the system energy. Under the current simulation conditions, the defect clustering fraction may be not directly dependent on the irradiation dose. Compared to vacancies, interstitials are more likely to form clusters, which may further cause the formation of 1/3<1210> interstitial-type dislocation loops extended along the (1010) plane. This study provides an important insight into the understanding of the irradiation damage behaviors for titanium.