• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1217-1233
• /
• 2018

Following a surge of interest in multi-unit risk in the last few years, many recent studies have suggested methods for multi-unit probabilistic safety assessment (MUPSA) and addressed several related aspects. Most of the existing studies though focused on two-unit nuclear power plant (NPP) sites or used rather simplified probabilistic safety assessment (PSA) models to demonstrate the proposed approaches. When considering an NPP site with three or more units, some approaches are inapplicable or yield very conservative results. Since the number of such sites is increasing, there is a strong need to develop and validate practical approaches to the related MUPSA. This article provides several detailed approaches that are applicable to multi-unit Level 1 PSA for sites with up to six or more reactor units. To validate the approaches, a multi-unit Level 1 PSA model is developed and the site core damage frequency is estimated for each of four representative multi-unit initiators, as well as for the case of a simultaneous occurrence of independent single-unit initiators in multiple units. For this purpose, an NPP site with six identical OPR-1000 units is considered, with full-scale Level 1 PSA models for a specific OPR-1000 plant used as the base single-unit models.

• 한국항해항만학회지
• /
• 제35권1호
• /
• pp.23-30
• /
• 2011

본 논문은, 국적일반화물선 공식안전성평가(Formal Safety Assessment, 이하 FSA) 연구의 1, 2 단계에 해당하는 위험요소 식별(Hazard identification) 및 식별된 사고 시나리오에 대한 위험도 분석(Risk analysis) 결과를 소개한 "국적일반화물선 초기안전성평가 연구(1)"에 이어 FSA 연구의 3, 4 그리고 5단계를 수행한 내용으로, 국적일반화물선의 운용 중 발생 가능한 위험을 저감할 수 있는 위험도제어방안들(Risk Control Options)을 식별하는 단계(Step 3)와 식별된 위험도제어방안들 중 전문가 의견수렴을 통하여 선별된 위험도제어방안들을 대상으로 한 비용-효과 평가 단계(Step 4: Cost-Benefit Assessment) 그리고 비용-효과 평가의 결과를 정리하여 국적일반화물선의 안전성 제고를 위한 구체적인 방안을 제안하는 단계(Step 5: Recommendation for Decision Making)의 결과를 소개하였다.

• 한국유기농업학회지
• /
• 제14권2호
• /
• pp.139-157
• /
• 2006

Biotechnology has reached the level of giving birth to new forms of life and with this is a growing controversy in the conflict between science and ethics. Especially, GMOs are closely linked to the food products we consume and thus, the majority of the public shows a very sensitive reaction to the safety of GMO food products. Many perspectives arose surrounding the issues of safety on the human body and the ecology. This outlines diverse structural mechanisms to be set up to ensure safety such as risk assessment, risk management etc. Despite the precautionary principle guaranteed in many ways, the problem arises whether and how this principle can be taken in the safety assessment. GMOs due to its uniqueness do not end with just the possession of the technology involved but must also be considered with the prerequisite that they could be cultured again. Therefore the reinforcement of safety assessment system is necessary. That is, the reinforcement of risk assessment including field tests, the consideration of socio-economic effects, the coordinated system of relevant authorities, the development of technology for safety assessment.

• Toxicological Research
• /
• 제17권
• /
• pp.41-45
• /
• 2001

The methods used for risk assessment from exposure to chemicals are well established. in most cases where toxicity other than carcinogenesis is being considered, the standard method relies on establishing the No Observed Adverse Effect Level (NOAEL) in the most sensitive animal toxicity study and using an appropriate safety factor (SF) to determine the exposure which would be associated with an acceptable risk. For carcinogens a different approach is used because it has been argued there is no threshold of effect. Thus mathematical equations are used to extrapolate from the high doses used in ani-mal experiments. These methods have been strongly criticised in recent years on several grounds. The most cogent criticisms are a) the equations are not based on a thorough understanding of the mechanisms of carcinogenesis and b) the outcome of a risk assessment based on such models varies more as a consequence of changes to the assumptions and equation used than it does from the data derived from carcinogenicity experiments. Other criticisms include the absence of any measure of the variance on the risk assessment and the selection of default values that are very conservative. Recent advances in the application of risk assessment emphasise that measures of both the exposure and the hazard should be considered as a distribution of values. The outcome of such a risk assessment provides an estimate of the distribution of the risks.

• 한국산림과학회지
• /
• 제110권2호
• /
• pp.210-216
• /
• 2021

우리나라 모든 산업에서 근골격계질환은 작업자들의 안전에 큰 영향을 미치고 있으며, 산림작업은 산업안전보건법에 따라 근골격계 부담작업으로 분류된다. 특히 벌도 및 가지제거작업은 주로 인력작업으로 실시되고 있으며, 작업원의 안정성 확보를 위해 작업자세에 대한 평가가 필요하다. 따라서 본 연구는 체인톱을 이용한 벌도 및 가지제거작업의 작업자를 대상으로 세가지 인간공학적 분석 도구(OWAS, RULA, REBA)를 이용하여 위험도를 평가하고, 평가기법별 작업자세에 대한 영향인자를 분석하였다. 벌도와 가지제거작업자세의 위험도는 RULA, OWAS, REBA 순으로 높게 평가되었으며, 대부분 2-3단계로 작업자세의 즉각 변경조치는 요구되지 않았다. 하지만 벌도작업에서 허리와 다리를 굽힌자세와 가지제거작업에서 벌도목 위에서 작업하는 자세는 위험도가 매우 높게 분석되었다. 또한 벌도작업의 경우 산지경사, 가지제거작업의 경우는 지상에서부터 벌도목 높이가 작업위험도 평가에 영향이 높은 것으로 분석되었다. 따라서 산림작업에 있어서 작업자의 안전성을 확보하기 위해 작업부하가 낮은 자세(벌도작업: 쪼그리는 자세, 가지제거작업: 허리와 다리가 곧은 자세)로 작업하는 것이 바람직한 것으로 사료된다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제17권5호
• /
• pp.1-9
• /
• 2012

The purpose of ecological risk assessment in soil ecosystem is to protect ecological receptors and to provide a scheme of efficient management for soil contaminants. Developed countries have already prepared the methodologies of ecological risk assessment by considering their soil properties, land use, and ecological receptors. In this study, we compared the soil ecological risk assessment processes in the similarity and differences in methodology. Four countries, except for USA, adjusted the toxicological data for ecological risk assessment, based on their representative soil properties because the soil properties affect toxic effects to ecological receptors. The soil ecological risk assessment methodology of Netherlands and UK was based on 'Technical guidance document on risk assessment (TGD)' of European Chemical Bureau (ECB). Australia, USA, and Canada developed their autonomous methodology. In the Netherlands, UK, Australia, and Canada, they employed the species sensitivity distribution (SSD) approach if sufficient toxicity data are available. The USA determined the ecological soil screening level by obtaining the geometric mean of toxicological data for three species. Furthermore, all countries consider secondary poisoning in their soil ecological risk assessment. The latest risk assessment methodology of soil ecosystem that this study investigated can be used to explore what Korea needs to develop the Korean ecological risk assessment methodology of soil ecosystem in the future.

• 시스템엔지니어링학술지
• /
• 제11권1호
• /
• pp.9-24
• /
• 2015

Construction industry faces a lot of inherent uncertainties and issues and the construction phase of nuclear power project is not free from this risk. This paper investigates promising methodologies to be used on nuclear power plant (NPP) construction schedule delay risk assessment by using entry level systems engineering approach. This study contains how the initial concept for the risk assessment methodology has been developed. In this point of view, this work structured on three main phases: needs analysis (NA), concept exploration (CE), and concept definition (CD) through systems engineering (SE) approach. Traditionally, the SE process is applied to technical development programs but this study opens up a new avenue that SE can also be successfully applied to the development and optimization of the risk assessment model. This study provides a rational and systematic process for developing and selecting the best risk assessment model. This paper selects analytic hierarchy process (AHP) method to assess NPP construction schedule delay risk for international project. As conclusion, the proposed concept and selected method can discriminate successfully and clearly among schedule delay risk assessment methods.

• 환경영향평가
• /
• 제1권1호
• /
• pp.51-59
• /
• 1992

Environmental Impact Assessment(EIA) is defined as an activity designed to identify and predict the impact on the environment. In the process of an EIA, the quantitative evaluation is generally performed for the air and water quality which have the national environmental quality standards. But the predicted values for the air and water quality are simply compared to the environmental standards. At present, the EIA process of Korea has no consideration for the possible human health risk resulting from the development projects. Environmental Health Impact Assessment(EHIA) is an applied methodology of EIA to estimate the acceptable health risk caused by a specified level of environmental pollutants. Estimating the excessive lifetime risk that is a possibility of dying of a certain disease by environmental contaminants, is useful as an evaluation technique of EHIA. It is recommanded the decision-makers to make efficient use of EHIA not only the development projects but also legislative proposals, policies and programmes in future.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제16권1호
• /
• pp.32-41
• /
• 2011

By using a newly developed Korean risk-based corrective action (K-RBCA) software (K-RBCA) and the RBCA Tool Kit, risk assessment was performed on a site that was contaminated with aromatic hydrocarbons and heavy metals. Eight chemicals including benzene, ethylbenzene, xylenes, naphthalene, benz(a) anthracene, benzo(b) fluoranthene, benzo(a) pyrene, and arsenic that exceeded the US EPA Soil Screening Level were chosen as the target pollutants. A conceptual site model was constructed based on the site-specific effective exposure pathways. According to the RBCA Tool Kit the carcinogenic risk of arsenic was larger than $10^{-6}$, which is the generally acceptable carcinogenic risk level. The K-RBCA estimated the same level of carcinogenic risk for arsenic. With the RBCA Tool Kit, the carcinogenic risk of benzo(a) pyrene was estimated to be about $1.3{\times}10^{-6}$. However, with the K-RBCA benzo(a) pyrene did not exhibit any risk. The inconsistency between the softwares was attributed to the different fundamental settings (i.e., medium division) between the two softwares. While the K-RBCA divides medium into surface soil, subsurface soil, and groundwater, the RBCA Tool Kit divides medium into only soil and groundwater. These differences lead to the different exposure pathways used by the two softwares. The K-RBCA considers the exposure pathways in surface soil and subsurface soil separately to estimate risk, however, the RBCA Tool Kit considers the surface soil and subsurface soil as one and uses the integrated exposure pathways to estimate risk. Thus the resulting risk is higher when the RBCA Tool Kit is used than when the K-RBCA is used. The results from this study show that there is no significant difference in the risks estimated by the two softwares, thus, it is reasonable to use the K-RBCA we developed in risk assessment of soil and groundwater. In addition, the present study demonstrates that the assessor should be familiar with the characteristics of a contaminated site and the assumptions used by a risk assessment software when carrying out risk assessment.

• 한국환경보건학회지
• /
• 제40권5호
• /
• pp.397-406
• /
• 2014

Objectives: Perchloroethylene (PCE) is a volatile chemical widely used as a solvent in the dry-cleaning and textile processing industries. It was evaluated as Group 2 "probably carcinogenic to humans" by the Integrated Risk Information System (IRIS) of the United State Environmental Protection Agency (U.S. EPA) in 2012. In order to provide a scientific basis for establishing risk management measures for chemicals on the national priority substances list, aggregate risk assessment was conducted for PCE, included in the top-10 substances. Methods: We conducted the investigation and monitoring of PCE exposure (e.g., exposure scenario, detection levels, and exposure factors, etc.) and assessed its multi-media (e.g., outdoor air, indoor air, and ground water) exposure risk with a deterministic and probabilistic approach. Results: In human risk assessment (HRA), the level of human exposure was higher in the younger age group. The exposure level through inhalation at home was the highest among the exposure routes. Outdoor air or uptake of drinking water represented less than 1% of total contributions to PCE exposure. These findings suggested that the level of risk was negligible since the Hazard Index (HI) induced by HRA was below one among all age groups, with a maximum HI value of 0.17 when reasonable maximum exposure was applied. Conclusion: In conclusion, it was suggested that despite low exposure risk, further studies are needed considering main sources, including occupational exposure.