• Journal of Radiation Industry
• /
• v.18 no.1
• /
• pp.23-33
• /
• 2024

This study was conducted to analyze the characteristics of three high-exposure tasks performed by radiation workers in Korean pressurized water reactors (PWRs) and to identify factors that reduce their exposure during work. Three high-exposure tasks were selected based on a previous study. In this previous study, nozzle dam installation and removal, eddy current testing, and manway opening and closing were determined as high-exposure tasks through normalization (radiation dose per unit time). Based on the analysis of the characteristics of the high-exposure tasks in this study, the high-exposure tasks were steam generator-related tasks performed inside and outside the water chamber. This study analyzed the reduction factors for high-exposure tasks and suggested improvements in terms of time, distance, and shielding. The use of the characteristics of high-exposure tasks and their dose reduction factors enables Korean PWRs to optimize radiation protection for workers who receive relatively high doses.

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

• Journal of Radiation Industry
• /
• v.18 no.3
• /
• pp.223-226
• /
• 2024

It is essential to precisely evaluate the expected dose (collective dose) before performing high-exposure tasks in nuclear power plants because those have a high potential to cause significant radiation exposure to workers. A dose evaluation method is to design the scenarios of high-exposure tasks using computational codes, which allows for the calculation of the expected collective dose. Although these computational scenarios are useful for estimating the expected radiation dose and establishing radiation protection plans, the calculated doses may not perfectly match the actual doses that workers receive during tasks due to differences between the scenario and the actual circumstances in the radiation fields. Therefore, this study presents a methodology for calculating correction factors to improve the accuracy of dose predictions from computational scenarios. This approach aims to make the predicted collective dose before the task closer to the actual dose received by workers, thereby enhancing radiation safety for personnel performing high-exposure tasks. Additionally, these correction factors will help accurately predict doses under various working conditions in the future, contributing to minimizing radiation exposure risks for nuclear power plant workers.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.17 no.4
• /
• pp.310-321
• /
• 2007

Status of benzene exposure was evaluated upon petrochemical workers in the Yeosu Industrial Complex, based on questionnaire responses by workers, review of previous work environment assessment reports between 1996 and 2004, in addition to short-term exposure measurements for unit tasks in the field. Questionnaire results showed that workers in the field were suffering concern on and symptoms of respiratory diseases, cancers or other illnesses of unknown causes. In particular, workers were highly worried about the risk of exposure to chemical hazards including benzene, while conducting specific tasks (e.g. sampling, draining, gauging) among normal operations during which equipments are opened and contents are exposedin the air, as well as periodic turnaround (TA) task. However, the review of previous work environment assessment reports found out that short-term exposure assessment data for unit tasks accounted for less than 1% of total data, and most of them were on 8-hr average exposure level. It also turned out that benzene was not detected in 83% of total samples, suggesting routine but pointless sampling has been repeated. Short-term exposure level was assessed focusing on tasks with high level of complaints on the exposure risk, based on the questionnaire responses. As predicted, a maximum of 741 ppm benzene exposure was reached depending on types and conditions of operations involved. In conclusion, these findings suggest that the evaluation and management on the short-term high exposure tasks including turnaround are crucial in reducing benzene exposure and preventing haematopoietic cancer in workers in the petrochemical industry.

• Journal of Environmental Health Sciences
• /
• v.36 no.4
• /
• pp.264-270
• /
• 2010

Agricultural workers are often exposed to high levels of dust during field operations. A systematic exposure assessment of annual task-weighted exposure has not been thoroughly examined. The occupational dust exposure in two wine grape vineyards was measured. Exposure levels to total and respirable dust were determined for a 1-year cycle of work. An operation profile including the frequency of tasks was established. The means of total and respirable dust exposure were $1.08\;mg/m^3$ and $0.07\;mg/m^3$, respectively. Based on the exposure for each task and the task frequency, task-weighted mean exposures to total and respirable dust were estimated as $1.115\;mg/m^3$ and $0.079\;mg/m^3$, respectively. The task-weighted exposure was significantly represented by three operations and could be attributed to the exposure frequency rather than the exposure intensity of operations. The measurement of a few of the most frequent tasks may be an alternative method of estimating task-weighted exposure. Agricultural dust exposure can be significantly reduced by targeting those tasks most important to task-weighted dust exposure.

• Journal of the Korea Safety Management & Science
• /
• v.26 no.2
• /
• pp.87-92
• /
• 2024

This study aims to compare six observational methods for assessing arm- and hand-intensive tasks, based on literature review. The comparison was conducted in viewpoints of body regions, force/external load, motion repetition, other factors including static posture, coupling, duration/break, pace, temperature, precision task, and final risk or exposure level. The number of risk factors assessed was more, and assessment procedure was more complex than the observational methods for assessing whole-body postural loads such as Ovako Working Posture Analysis System(OWAS), Rapid Upper Limb Assessment(RULA), and Rapid Entire Body Assessment(REBA). Due to these, the intra- and inter-reliabilities were not high. A past study showed that while Hand Arm Risk Assessment Method(HARM) identified the smallest proportion of the work tasks as high risk, Strain Index(SI) and Quick Exposure Check(QEC) hand/wrist were the most rigorous with classifying most work tasks as high risk. This study showed that depending on the observational technique compared, the evaluation factors, risk or exposure level, and evaluation results were different, making it necessary to select a technique appropriate for the characteristics of the work being assessed.

• Safety and Health at Work
• /
• v.11 no.3
• /
• pp.335-346
• /
• 2020

Background: Nursing service is a nonroutine work with an excessive physical load and diverse tasks. This study derived representative common tasks based on the frequently occurring tasks with a high physical load in the nursing workers' daily work and developed indicators to evaluate the work risk by reflecting the characteristics of nonroutine work. Methods: Common tasks were classified through the following stages: literature review, first focus group interview (FGI) with experts, first classification of common tasks, second FGI with hospital health managers, a survey of nursing service workers, and the final classification of common tasks for each task type. To develop an objective risk index for physical load assessment, we investigated the frequency and duration of the derived common tasks via survey. Results: Nursing common tasks were categorized into six task types and 56 subtasks. To evaluate the risks of various tasks in nonroutine works, three frequencies and three working time levels were defined by examining the task frequency and working hours. Exposure time was defined to reflect the characteristics of a nonroutine job. The final risk assessment was the product of the exposure time level and job intensity level. From this, four risk action levels were derived. Conclusion: This study has the advantage of solving the problem of focusing on some tasks in evaluating the physical load. It was meaningful in that a new risk assessment index based on exposure time was proposed based on the development of an evaluation scale for frequency and time by reflecting the characteristics of nonroutine work.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.1
• /
• pp.1-12
• /
• 2019

Objective: Significant concerns have been raised over chemical exposure and potential health risks such as increased cancer mortality among laboratory workers. The aim of this study was to investigate the overall exposure and unit task exposure levels of researchers in organic synthesis laboratories at universities. Methods: Seventy-seven personal Time-weighted average(TWA) samples and 139 task-based samples from four organic synthesis laboratories at two universities were collected over three days. The concentrations of acetone, chloroform, dichloromethane(DCM), diethyl ether, ethyl acetate, n-hexane, tetrahydrofuran(THF), benzene, toluene, and xylene were determined using the GC-FID. Results: The most frequently used chemicals in the laboratories were acetone, DCM, n-hexane, methanol, and THF. Carcinogens such as benzene, chloroform, and DCM were used in one or more laboratories. The TWA full-shift exposures of researchers to acetone was the highest(ND-59.3 ppm). Benzene was observed above the occupational exposure limit in 18-40% of the samples. The levels of exposure to organic solvents were statistically different by task(p<0.05), while washing task was the highest. Washing was not perceived as a part of the real lab tasks. Rather it was considered as simple dish-washing or experimental preparation and performed in an open sink where exposure to organic solvents was unavoidable. TWAs and task-based concentrations were compared by substance, which suggests that TWA-based assessment could not reflect short-term and high concentration exposures. Conclusions: Laboratory workers may be exposed to various organic solvents at levels of concern. TWA-based measurement alone cannot guarantee holistic exposure assessment among lab workers as their exposures are very dependent on their tasks. Further investigation and characterization for specific tasks and overall chronic exposures will help protect lab workers from unnecessary exposure to chemicals while they perform research.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.32 no.2
• /
• pp.137-145
• /
• 2022

Objectives: This study aimed to identify PM₁₀ mass concentration levels and conduct peak identification during five tasks in agricultural works. Methods: We investigated five agricultural tasks in 12 farms, which were harvesting, plowing, sowing, planting, and decapitation. All samples were measured by using the portable aerosol spectrometer(PAS 1.108) and the aerosol monitor(SidePak AM520). The collected data were compared with the national PM₁₀ concentrations. They were calculated to descriptive statistics, independent t-test, or ANOVA, and the peak identification on time series graph. Results: The ten investigated farms showed no significant difference with the national PM₁₀ concentrations, but the two greenhouses(AM, 143.31, 85.16 ㎍/m³) showed significant difference(p<0.05). As a result of the peak identification, the harvesting tasks showed repeated peak occurrence with the background concentration level of about 50 ㎍/m³. For plowing and sowing tasks, the peak occurred intermittently when the working was conducted near the sampling sites. Among the five tasks, the arithmetic mean of the harvesting task was 138.84±294.71 ㎍/m³, which was significantly higher than the other tasks(p<0.05). In addition, the case of using a tractor was higher than the case of not using the tractor(p<0.05), and the driver's seat showed the highest concentration(AM, 95.81 ㎍/m³). Conclusions: Works in greenhouses might have exposure to PM₁₀, while outdoor works is similar to general atmospheric PM₁₀ concentration levels. However, there is a possibility of intermittent exposure to high concentrations of PM₁₀ depending on the characteristics of agricultural tasks.

• Journal of Radiation Industry
• /
• v.11 no.3
• /
• pp.123-130
• /
• 2017

Concerns about high radiation exposure to the hands of radiation workers who may contact with radioactive contamination on surfaces in a nuclear power plant (NPP) had been raised, and the Korean regulatory body required the extremity dose estimation during contact tasks with radioactive materials. Korean NPPs conducted field tests to identify the incident radiation to the hands of radiation workers who may contact with radioactive contamination during maintenance periods. The results showed that the radiation fields for contact tasks are dominated by high energy photons. It was also found that the radiation doses to the hands of radiation workers in Korean NPPs were much less than the annual dose limits for extremities. This approach can be applicable to measure and estimate the extremity dose to the hands of medical workers who handle the radioactive materials in a hospital.