• Tunnel and Underground Space
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• v.11 no.2
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• pp.132-145
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• 2001

The purpose and need of the study is to quantify the advantage or disadvantage of the environmental friendliness of the partitioning of nuclear fuel cycle. To this end, a preliminary study on the quantitative effect of the partition on the permanent disposal of spent PWR and CANDU fuel (HLW) was carried out. Before any analysis, the so-called reference radionuclide release scenario from a potential repository embedded into a crystalline rock was developed. Firstly, the feature, event and processes (FEPs) which lead to the release of nuclides from waste disposed of in a repository and the transport to and through the biosphere were identified. Based on the selected FEPs, the ‘Well Scenario’which might be the worst case scenario was set up. For the given scenario, annual individual doses to a local resident exposed to radioactive hazard were estimated and compared to that from direct disposal. Even though partitioning and transmutation could be an ideal solution to reduce the inventory which eventually decreases the release time as well as the peaks in the annual dose and also minimize the repository area through the proper handling of nuclides, it should overcome major disadvantages such as echnical issues on the partitioning and transmutation system, cost, and public acceptance, and environment friendly issues. In this regard, some relevant issues are also discussed to show the direction for further studies.

• Journal of Radiation Industry
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• v.17 no.3
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• pp.239-256
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• 2023

The classification of the radiation work performed in Korean nuclear power plants (NPPs) must be understood to provide workers with more comprehensive radiation protection. This study used annual reports on occupational exposure to investigate and analyze the similarities and differences in the radiation work performed in Korean NPPs with pressurized water reactors (PWRs) and pressurized heavy water reactors (PHWRs). The results showed that the radiation work performed in Korean NPPs could be classified into three categories. Category 1 contains work at the highest level. This work can be divided into individual tasks belonging to Category 2, which enables the evaluation of the radiation dose during the work. The work in Category 2 consists of tasks from Category 3, which contains basic detailed tasks that are not further subdivided. This study emphasized the need for the systematic management of the radiation work performed in both Korean PWRs and PHWRs, such as the tasks in Category 3, which are similar, with similar working conditions, for PWRs and PHWRs. It also suggested the need to establish a list of radiation work for decommissioning because Kori Unit 1 and Wolsong Unit 1 are currently in permanent shutdown and preparations are being made for their decommissioning.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.2
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• pp.105-112
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• 2004

A waste container, one of the key components of a multi-barrier system in a potential high level radioactive waste (HLW) repository in Korea ensures the mechanical stability against the lithostatic pressure of a deep geologic medium and the swelling pressure of the bentonite buffer. Also, it delays potential release of radionuclides for a certain period of time, before it is corroded by intruding impurities. Even though the material of a waste container is carefully chosen and its manufacturing processes are under quality assurance processes, there is a possibility of initial defects in a waste container during manufacturing. Also, during the deposition of a waste container in a repository, there is a chance of an incident affecting the integrity of a waste container. In this study, the appropriate Features, Events, and Processes(FEP's) to describe these incidents and the associated scenario on radionuclide release from a container to the biosphere are developed. Then the total system performance assessment on the Initial waste Container Failure (ICF) scenario was carried out by the MASCOT-K, one of the probabilistic safety assessment tools KAERI has developed. Results show that for the data set used in this paper, the annual individual dose for the ICF scenario meets the Korean regulation on the post closure radiological safety of a repository.

• Journal of Radiation Industry
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• v.18 no.2
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• pp.117-126
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• 2024

This study aims to identify high exposure tasks among the tasks performed in domestic nuclear power plants as a basis for developing training programs to improve the efficiency of workers' work. To this end, we first analyzed the exposure status of radiation work in domestic nuclear power plants. Radiation tasks in nuclear power plants were categorized, collective doses were investigated, and the collective doses were calculated based on the collective doses, and representative high exposure tasks were identified. We found that the collective and individual doses in domestic nuclear power plants are continuously decreasing, but there is an imbalance of exposure among workers. In terms of work classification, nuclear power plants are managed in 236 work codes based on light water reactors and 181 work codes based on heavy water reactors, depending on the work equipment and location. Among the total work codes, 23 codes have an annual average dose exceeding 10 μSv, and based on this, 10 representative high exposure tasks were derived. The representative high exposure tasks were selected as S/G nozzle dam work, S/G debris removal work, nuclear instrumentation system, S/G eddy current detection work, and insulation work. The results of this study are expected to serve as an important basis for reducing the exposure of workers in nuclear power plants and improving work efficiency.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.229-232
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• 2003

A waste container, one of the key compartments in a multi-barrier system for a potential high level radioactive waste (HLW) repository in Korea ensures the mechanical stability against the lithostatic pressure of a deep geologic strata and the swelling pressure of the bentonite buffer. Also, it prohibits potential release of radionuclides for a certain period of time. before it is corroded by impurities. Even though the materials of a waste container is carefully chosen and all manufacturing processes are under heavy quality assurance, there might be a slight chance of intial defects in a waste container. Also, during the deposition of a waste container in a repository, there might be a chance of an incident affecting the integrity of a waste container. In this study, the FEP's and the scenarios over radiological impact of a potential initial waste container defect was developed. Then the total system performance assessment on this initial waste container failure (ICF) scenario was carried out by the MASCOT-K, one of the probabilistic safety assessment tools KAERI has developed. Results show that for the data set studied in this paper, the annual individual dose by the ICF scenario well meets the KINS regulation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.4
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• pp.253-262
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• 2004

Construction of tunnels in a deep crystalline host rock for a potential High-Level Radioactive Waste(HLW) repository inevitably generates an excavation disturbed zone (EDZ). There have been a series of debates on whether a permeability in an EDZ increases or not and what would be the maximum depth of an EDZ. Recent studies show mixed opinions on permeability. However, there has been an international consensus on the thickness of an EDZ; 30 cm for TBM and 1 meter for controlled blast. One of the impacts of an EDZ is on determining the distance between adjacent deposition holes. The void gap by the excavation hinders relaxation of temperature profiles so that the current Korean reference designing distance between holes should be stretched out more to keep the maximum temperature in a buffer region below 100 degrees Celsius. The other impact of an EDZ is on the long-term post closure radiological safety. To estimate the impact, the reference scenario, the well scenario, is chosen. Released nuclides diffuse through a bentonite buffer region experiencing strong sorption and reach a fracture surrounded by a porous medium. Inside a fractured porous region, radionuclides migrate by advection and dispersion with matrix diffusion into a porous medium. Finally, they reach a well assumed to be a source of potable water for local residents. The annual individual dose is assessed on this well scenario to find out the significance of an EDZ. A profound sensitivity study was performed, but all results show that the impact is negligible. Even though the role of an EDZ turns out to be limited on overall safety assessment, still it is worthwhile to study the chemical role of an EDZ, such as a potential source for natural colloids, potential sealing of an open fracture by fine clay particles generated by the process of an EDZ, and alteration of a sorption mechanism by an EDZ in the future.

• Journal of agricultural medicine and community health
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• v.48 no.3
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• pp.178-188
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• 2023

Objective: Self perceived health status dose not only reflects an individual's perception of their overall well-being but is also known to be influenced by various aspects of life. Rural areas tend to have relatively lower quality of life compared to urban areas. Therefore, this study aims to investigate factors related to Self perceived health status among farmers. Methods: In the subjective health status questionnaire, responses of "very healthy" and "healthy" are classified as 'good', whereas "average", "unhealthy" or "very unhealthy" are classified as indicative of a 'poor' subjective health status. Logistic regression analysis was conducted to calculate odds ratios(OR), aiming to investigate factors related to self perceived health status. Results: The OR for self perceived health status as poor was statistically significant for females at 2.32(95% CI 1.47-3.67), for individuals working in greenhouses at 1.43(95% CI 1.01-1.98), for current smoker at 1.50(95% CI 1.02-2.08), and for those who experienced symptoms after pesticide exposure at 1.74(95% CI 1.13-2.67). An annual income of 50 million won or more had a statistically significant OR of 0.51(95% CI 0.28-0.91), education level of high school and above had an OR of 0.45(95% CI 0.32-0.63), and engaging in physical exercise had an OR of 0.61(95% CI 0.42-0.89). Conclusions: The factors related to self perceived health status were identified as sex, smoking, cultivation type, presence of symptoms after pesticide exposure, annual income, education level, and exercise status. The significance of this study lies in providing foundational data for the development of health management programs for farmers.

• Journal of Korea Association of Health Promotion
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• v.3 no.1
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• pp.72-83
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• 2005

The present pilot project was executed to recommend a strategy of clonorchiasis control in China. The pilot area of this project was Zhaoyuan, Hailin, and Ningan, Heiloagjiang province. A baseline survey subjecting 4,865 residents in Heilongjiang confirmed Zhaoyuan asa high endemic area and Hailin and Ningan as moderate endemic areas. Six different control strategies were implemented in Zhaoyuan, two were in Hailin, and one was in Ningan. Including the baseline survey and project programs from 2000 to 2004, total 63,274subject-times were examined of their feces for Clonorchiseggs, 26,680 were treated, 10,082 were screened by ELISA, and 6,130 subjects were examined of their liver by sonography. The egg Positive rates in 6 villages of Zhaoyuan were as high as 44.8% 70,0%. Following the protocolof each strategy, the subjected residents were examined of their feces and treated with 25 mg/kg praziquantel, 3 times. Except the control group, all of the villages showed 72.8% to 92.0% reduction of their original egg Positive rates at Zhaoyuan. Mass treatments of all subjected residents in 2001 and 2003 reduced the egg rate from 68.8% to18.7% and 4 annual mass treatments reduced the rate from 44.8% in 2001 to 8.7% in 2004.Selective annual treatments of egg positive subjects reduced the egg rates from 50.8% in2001 to 13.8% in 2004 or from 70.0% in 2001 to 11.6% in 2004, and two treatments in a year reduced the rate from 57.6% in 2001 to 4.6% in 2004. According to repeated treatments, EPG counts decreased remarkably. In moderate endemic areas, the original egg rates were 22.6% and 28.3% in 2001 but were 1.7% and 1.1% after 2 or 3 selective treatments. The present findings of the chemotherapeutic control of clonorchiasis prove that repeated medication is important. The reduction is directly correlated with dose of praziquantel but not with mass or selective treatments. Chemotherapeutic control of reservoirhosts has little effect on reinfection of clonorchiasis because the field along the Songhua-jiang is too wide to be impacted. ELISA confirmed many serologically positive cases to Clonorchisantigen but only a few cases were positive to other antigens (Paragonimus, cysticercus, sparganum). The abdominal soaography visualized intrahepatic bile duct dilatation and periductal echo in 2,002 of 6,070 examined subjects. In addition to these examinations and treatment, health education supplemented tㅗe control activities. The present findings prove clonorchiasis is very widely prevalent and heavily endemic along the rivers in Heiloagjiang. The results suggest that group chemotherapy with praziquantel is effective to reduce endemicity of clonorchiasis. Mass treatment without individual fecal examination is recommended in heavy endemic areas where the egg rate is over 40% while one selective treatment is effective enough in moderate endemic areas.