Nuclear Power Plant Workers Research Articles

Development of an information reference system using reconstruction models of nuclear power plants

Abstract Many nuclear power plants in Japan are approaching the end of their planned operational life spans. They must be decommissioned safely in the near future. Using augmented reality (AR), workers can intuitively understand information related to decommissioning work. Three-dimensional (work-site) reconstruction models of dismantling fields are useful for workers to observe the conditions of dismantling field situations without visiting the actual fields. This study, based on AR and work-site reconstruction models, developed and evaluated an information reference system. The evaluation consists of questionnaires and interview surveys administered to six nuclear power plant workers who used this system, along with a scenario. Results highlight the possibility of reducing time and mitigating mistakes in dismantling fields. Results also show the ease of referring to information in dismantling fields. Nevertheless, it is apparently difficult for workers to build reconstruction models of dismantling fields independently.

Exhibition review- The Disasters of Peace: Social discontent in the manga of Tsuge Tadao and Katsumata Susumu – Exhibited at the Honolulu Museum of Art

Art cannot exist in a vacuum, and certainly cannot be fully appreciated without the proper context; this is especially true of the Honolulu Museum of Art exhibit The Disasters of Peace: Social Discontent in the Manga of Tsuge Tadao and Katsumata Susumu, where the sketches of socially-minded manga artists Tsuge Tadao and Katsumata Susumu were on display for the first time in the United States from 30 November 2017 through 15 April 2018. Both artists use manga as a medium to explore the daily struggles faced by marginalised communities in Japan, based on their own personal experiences. Tsuge, born and raised in the slums of postwar Tokyo, offers insight into the plight of veterans and the homeless and draws on his experience working in a blood bank in the decades after the war. Katsumata was an anti-nuclear activist whose work exposed the inhumane conditions of nuclear power plant workers in Japan decades before the Fukushima Daiichi nuclear disaster. Stephen Salel, the museum’s Robert F. Lange Curator of Japanese Art, constructed for visitors a number of wonderfully in-depth and interactive supplementary audiovisual aids to facilitate a richer understanding of the sociological underpinnings of the exhibit. According to Salel, the curatorial intent of the exhibit was to allow visitors to relate to the difficulties and realities depicted in the featured work, and to examine how art can speak to past events around the world that might echo what other communities currently face. The Disasters of Peace presented the viewing public with an unusual opportunity to learn about the struggles of Japan’s postwar society. Two walls of text were placed at [...]

Current situations and discussions in Japan in relation to the new occupational equivalent dose limit for the lens of the eye

Since the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye in 2011, there have been extensive discussions in various countries. This paper reviews the current situation in radiation protection of the ocular lens and the discussions on the potential impact of the new lens dose limit in Japan. Topics include historical changes to the lens dose limit, the current situation with occupational lens exposures (e.g., in medical workers, nuclear workers, and Fukushima nuclear power plant workers) and measurements, and the current status of biological studies and epidemiological studies on radiation cataracts. Our focus is on the situation in Japan, but we believe such information sharing will be useful in many other countries.

Target/signalling pathways of natural plant-derived radioprotective agents from treatment to potential candidates: A reverse thought on anti-tumour drugs.

Radiation damage can occur in nuclear power plant workers when physical protections fail, which results in nuclear leakage through the protective layers. Alternatively, workers may be unable to use physical protection in time (in the case of a sudden nuclear weapons attack). In addition, patients who receive local radiotherapy and are not allowed to adopt local physical protection may experience radiation damage. Thus, protection against chemical radiation has become indispensable. In view of the side effects caused by synthetic radioprotective agents (such as amisfostine), searching for radioprotective agents from plant sources is an alternative strategy. Radiation damage can cause multiple signalling pathway disturbances, leading to multiple organ injuries. Changes in these signalling pathways can lead to apoptosis, necrosis, and autophagy, as well as organ fibrosis, atrophy, and inflammation. Through literature searches, we determined that most targets for treating radiation injury are mechanistically opposite those of anti-tumour agents. This is likely attributable to the idea that anti-tumour agents promote cell necrosis or apoptosis, whereas the goal of anti-radiation agents is to promote cell survival or autophagy. This observation has important theoretical and practical significance when searching and developing new radioprotective agents derived from plant extracts. Further, it has important guiding value for meeting military needs and serving the public.

0325 INSOMNIA IN RELATION TO DISASTER-RELATED EXPERIENCES AMONG FUKUSHIMA NUCLEAR PLANT WORKERS: THE FUKUSHIMA NEWS PROJECT STUDY

The Fukushima Nuclear Energy Workers’ Support (NEWS) project study previously showed that experiences related to the Fukushima nuclear disaster had a great impact on psychological states, which may be linked with insomnia among the nuclear plant workers. However, the complex mechanisms that disaster-related experiences cause insomnia are not fully understood. A total of 1,456 nuclear power plant workers who responded a questionnaire on insomnia-related symptoms measured by Athens Insomnia Scale (AIS) and disaster-related experiences in 2011. Path analysis was used to examine the potential effect of disaster-related experiences, age and gender on three types of insomnia (difficulty in initiating sleep; difficulty in maintaining sleep; early morning awakening). We hypothesized that disaster-related experiences had a direct effect on insomnia and an indirect effect mediated by the experience of discrimination. Five disaster-related experiences were found to significantly influence insomnia: discrimination, life-threatening danger, major property loss, witnessing of plant explosion, and home evacuation. Difficulty in initiating sleep was significantly related to all five events but mainly to the experiences of life-threatening danger and witnessing of the explosion. Difficulty in maintaining sleep was significantly related to experiences of discrimination and life-threatening danger. Early morning awakening was significantly related to age and experiences of discrimination, life-threatening danger and home evacuation. Major property loss and experience of life-threatening danger were the two main significant determinants of discrimination. Life-threatening experiences (i.e., life-threatening danger, witnessing of the explosion) may conjure up disturbing scenes that hamper sleep initiation. However, early morning awakening might be related to uncertainty of living (home evacuation). Discrimination was found to be associated with all three types of insomnia and was also influenced by other experiences, suggesting that providing comprehensive supports to these workers suffering from discrimination might be the most beneficial way of reducing insomnia-related problems.

Risk of death from circulatory diseases in a cohort of patients exposed to chronic radiation

To assess mortality from circulatory diseases (CD) in a cohort of workers exposed occupationally to chronic radiation in relation to external and internal exposure, by taking into account known non-radiation risk factors (RFs), such as smoking (including smoking index), alcohol consumption, hypertension, and body mass index. Mortality from CD (ICD-10: I00 - I99) was studied in a cohort of 22,377 nuclear power plant («Mayak» Production Association) workers exposed occupationally to chronic radiation. The study was based on the individual dose estimates of external and internal exposure taken from the new Mayak workers dosimetry system 2008 (MWDS-2008). The quantitative characteristics of smoking (smoking index) were used for the first time to assess the risk for CD in the cohort of workers exposed to chronic radiation. There was a statistically significant linear relationship between CD mortality and external gamma-dose after adjusting for the non-radiation RFs; the excess relative risk per unit dose (ERR/Gy) was 0.05 (95% confidence interval (CI): 0 to 0.11). Introducing an additional adjustment for internal alpha-dose resulted in a twofold increase in ERR/Gy=0.10 (95% CI: 0.02 to 0.21). There was a statistically significant increasing trend in CD mortality with the elevated absorbed dose from internal alpha-radiation in the liver (ERR/Gy=0.27; 95% CI: 0.12 to 0.48). However, ERR/Gy decreased and lost its statistical significance after adjusting for external gamma-dose. The results of this study are in good agreement with risk estimates obtained in the Japanese cohort of atomic bomb survivors and in the cohorts of occupationally exposed workers.

The longitudinal mental health impact of Fukushima nuclear disaster exposures and public criticism among power plant workers: the Fukushima NEWS Project study.

The Fukushima Daiichi and Daini Nuclear Power Plant workers experienced multiple stressors as both victims and onsite workers after the 2011 Great East Japan Earthquake and subsequent nuclear accidents. Previous studies found that disaster-related exposures, including discrimination/slurs, were associated with their mental health. Their long-term impact has yet to be investigated. A total of 968 plant workers (Daiichi, n = 571; Daini, n = 397) completed self-written questionnaires 2-3 months (time 1) and 14-15 months (time 2) after the disaster (response rate 55.0%). Sociodemographics, disaster-related experiences, and peritraumatic distress were assessed at time 1. At time 1 and time 2, general psychological distress (GPD) and post-traumatic stress response (PTSR) were measured, respectively, using the K6 scale and Impact of Event Scale Revised. We examined multivariate covariates of time 2 GPD and PTSR, adjusting for autocorrelations in the hierarchical multiple regression analyses. Higher GPD at time 2 was predicted by higher GPD at time 1 (β = 0.491, p < 0.001) and discrimination/slurs experiences at time 1 (β = 0.065, p = 0.025, adjusted R 2 = 0.24). Higher PTSR at time 2 was predicted with higher PTSR at time 1 (β = 0.548, p < 0.001), higher age (β = 0.085, p = 0.005), and discrimination/slurs experiences at time 1 (β = 0.079, p = 0.003, adjusted R 2 = 0.36). Higher GPD at time 2 was predicted by higher GPD and discrimination/slurs experience at time 1. Higher PTSR at time 2 was predicted by higher PTSR, higher age, and discrimination/slurs experience at time 1.

Development of digital device based work verification system for cooperation between main control room operators and field workers in nuclear power plants

Digital technologies have been applied in the nuclear field to check task results, monitor events and accidents, and transmit/receive data. The results of using digital devices have proven that these devices can provide high accuracy and convenience for workers, allowing them to obtain obvious positive effects by reducing their workloads. In this study, as one step forward, a digital device-based cooperation support system, the nuclear cooperation support and mobile documentation system (Nu-COSMOS), is proposed to support communication between main control room (MCR) operators and field workers by verifying field workers’ work results in nuclear power plants (NPPs).The proposed system consists of a mobile based information storage system to support field workers by providing various functions to make workers more trusted by MCR operators; also to improve the efficiency of meeting, and a large screen based information sharing system supports meetings by allowing both sides to share one medium. The usability of this system was estimated by interviewing field operators working in nuclear power plants and experts who have experience working as operators.A survey to estimate the usability of the suggested system and the suitability of the functions of the system for field working was conducted for 35 subjects who have experience in field works or with support system development-related research. The usability test was conducted using the system usability scale (SUS), which is widely used in industrial usability evaluation. Using questionnaires made specifically for this test, a function suitability was evaluated to determine whether the system stores work results in sufficient detail, without any disadvantages for field workers.Based on the results of the questionnaires, it is expected that the functions of the cooperation and work verification support system will be useful for understanding field workers’ work results if the manual or the set of guidelines for using the suggested system is well constructed.

Development and evaluation of a technique for in vivo monitoring of 60Co in human lungs

60Co is a fission product of 235U and represents a risk of internal exposure of workers in nuclear power plants, especially those involved in the maintenance of potentially contaminated parts and equipment. The control of 60Co intake by inhalation can be performed through in vivo monitoring. This work describes the evaluation of a technique through the minimum detectable activity and the corresponding minimum detectable effective doses, based on biokinetic and dosimetric models of 60Co in the human body. The results allow to state that the technique is suitable either for monitoring of occupational exposures or evaluation of accidental intake.

Assessment of Some Immune Parameters in Occupationally Exposed Nuclear Power Plant Workers: Flow Cytometry Measurements of T Lymphocyte Subpopulations and Immunoglobulin Determination.

A 10-year survey of immune status of nuclear power plant (NPP) workers was assessed by cellular and humoral immune parameters. The cumulative doses of NPP workers were in the range of 0.06 to 766.36 mSv. The results did not show significant deviations in the studied parameters of cellular and humoral immunity, but a tendency of elevated values in CD3+4+ helper inducers cells, especially its CD4+62L+ subpopulation, regulatory CD4+25+ cells, CD8+28+ cytotoxic subpopulation, and immunoglobulin M, was established. The observed trend of the above-mentioned parameters could be interpreted by assumption that while the adaptation processes are dominated with low prevalence of T-helper (Th) 1 immune response to cumulative doses less than 100 mSv, a switch to Th-2 response occurred at doses above 100 mSv. The impact of a number of other confounding factors on the immune system does not allow definitive conclusions about the direct radiation-induced changes in immune parameters.

국내 원전 종사자의 방사선량 : 2009-2013

Although the perfomance indicators of the nuclear power plants in Korea show optimal, it requires detailed analysis and discussion centered on the radiation dose. As analysis methods, analysis on the radiation dose of nuclear power plants over the past five years was assessed by comparing the relevant radiation dose of radiation workers and per capita average annual radiation dose of the world's major nuclear power stations was also analyzed. The radiation workers over the annual radiation dose limit of 50 mSv were not. The contrast ratio of the radiation exposure according to the reactor type was the normal operation of PHWR was 6.2% higher than those of the PWR. This shows the radiation work of PHWR during normal driving operation is much more than those of PWR. According to the Performance Indicators of the World Association of Nuclear Operator, the annual radiation dose per unit in 2013 showed 527 man-mSv of Korea is the best country among the major nuclear power generating states, the world average was 725 man-mSv. The annual per capita radiation dose is about 80% less than 1 mSv of the public dose limit and also the average per capita dose showed a very low level as 0.82 mSv. Workers in related organizations showed 1.07 mSv, the non-destructive inspection agency workers showed 3.87 mSv. The remarkable results were due to radiation reduced program such as development of radiation shielding and radiation protection. In conclusion, the radiation exposured dose of nuclear power plants workers in Korea showed a trend which is ideally reduced. But more are expected to be difficul and the psychological insecurity against the operation of the nuclear power plants is existed to the residents near the nuclear power plants. So the radiation dose reduction policy and radiation dose follow up study of nuclear power plants will be continously excuted.

Effects of Low Dose Radiation on DNA Methylation in Nuclear Power Plant Workers.

Effects of Low Dose Radiation on DNA Methylation in Nuclear Power Plant Workers.

Verification by the FISH translocation assay of historic doses to Mayak workers from external gamma radiation.

The aim of this study was to apply the fluorescence in situ hybridization (FISH) translocation assay in combination with chromosome painting of peripheral blood lymphocytes for retrospective biological dosimetry of Mayak nuclear power plant workers exposed chronically to external gamma radiation. These data were compared with physical dose estimates based on monitoring with badge dosimeters throughout each person's working life. Chromosome translocation yields for 94 workers of the Mayak production association were measured in three laboratories: Southern Urals Biophysics Institute, Leiden University Medical Center and the former Health Protection Agency of the UK (hereinafter Public Health England). The results of the study demonstrated that the FISH-based translocation assay in workers with prolonged (chronic) occupational gamma-ray exposure was a reliable biological dosimeter even many years after radiation exposure. Cytogenetic estimates of red bone marrow doses from external gamma rays were reasonably consistent with dose measurements based on film badge readings successfully validated in dosimetry system "Doses-2005" by FISH, within the bounds of the associated uncertainties.

The merits and limits of pooling data from nuclear power worker studies

The merits and limits of pooling data from nuclear power worker studies

Dose reconstruction for the million worker study: status and guidelines.

The primary aim of the epidemiologic study of one million U.S. radiation workers and veterans [the Million Worker Study (MWS)] is to provide scientifically valid information on the level of radiation risk when exposures are received gradually over time and not within seconds, as was the case for Japanese atomic bomb survivors. The primary outcome of the epidemiologic study is cancer mortality, but other causes of death such as cardiovascular disease and cerebrovascular disease will be evaluated. The success of the study is tied to the validity of the dose reconstruction approaches to provide realistic estimates of organ-specific radiation absorbed doses that are as accurate and precise as possible and to properly evaluate their accompanying uncertainties. The dosimetry aspects for the MWS are challenging in that they address diverse exposure scenarios for diverse occupational groups being studied over a period of up to 70 y. The dosimetric issues differ among the varied exposed populations that are considered: atomic veterans, U.S. Department of Energy workers exposed to both penetrating radiation and intakes of radionuclides, nuclear power plant workers, medical radiation workers, and industrial radiographers. While a major source of radiation exposure to the study population comes from external gamma- or x-ray sources, for some of the study groups, there is a meaningful component of radionuclide intakes that requires internal radiation dosimetry assessments. Scientific Committee 6-9 has been established by the National Council on Radiation Protection and Measurements (NCRP) to produce a report on the comprehensive organ dose assessment (including uncertainty analysis) for the MWS. The NCRP dosimetry report will cover the specifics of practical dose reconstruction for the ongoing epidemiologic studies with uncertainty analysis discussions and will be a specific application of the guidance provided in NCRP Report Nos. 158, 163, 164, and 171. The main role of the Committee is to provide guidelines to the various groups of dosimetrists involved in the MWS to ensure that certain dosimetry criteria are considered: calculation of annual absorbed doses in the organs of interest, separation of low and high linear-energy transfer components, evaluation of uncertainties, and quality assurance and quality control. It is recognized that the MWS and its approaches to dosimetry are a work in progress and that there will be flexibility and changes in direction as new information is obtained with regard to both dosimetry and the epidemiologic features of the study components. This paper focuses on the description of the various components of the MWS, the available dosimetry results, and the challenges that have been encountered. It is expected that the Committee will complete its report in 2016.

Radiation-induced changes in DNA methylation and their relationship to chromosome aberrations in nuclear power plant workers

Purpose: We investigated the association between occupational radiation exposure and DNA methylation changes in nuclear power plant workers. We also evaluated whether radiation- induced DNA methylation alterations are associated with chromosome aberrations.Materials and methods: The study population included 170 radiation-exposed workers and 30 controls. We measured global, long interspersed nuclear element-1 (LINE-1), and satellite 2 methylation levels in blood leukocyte DNA. The analysis of chromosome aberrations was performed on peripheral lymphocytes.Results: Global DNA methylation levels were lower in radiation-exposed workers than in controls. The methylation levels were negatively associated with the recent 1.5-year radiation dose in a multiple linear regression model (β = − 0.0088, p ≤ 0.001); the levels increased proportionally with the total cumulative dose in radiation-exposed workers. LINE-1 methylation levels were higher in radiation-exposed workers than in controls and were significantly associated with the total cumulative radiation dose in a multiple linear regression model (β = − 0.031, p = 0.035). Global DNA methylation levels were also correlated with chromosome aberrations among workers. Workers with low global methylation levels had a higher frequency of chromosome aberrations than did subjects with high global methylation levels.Conclusion: Occupational exposure to low-dose radiation could affect DNA methylation levels, and the radiation-induced DNA methylation alterations may be associated with chromosome aberrations.

Annexin V FITC conjugated as a radiation toxicity indicator in lymphocytes following radiation overexposure in radiotherapy programs.

Background:Following human radiation exposure in hospital or accidents, dose assessments are of prime importance in radiation accidents. These issues are of continuing importance with respect to socioeconomic policy relating to the industrial and medical uses of ionizing radiation, and also for risk assessment among people who are occupationally exposed to low and/or high linear energy transfer (LET) radiation, such as astronauts, pilots, stewardesses, nuclear power plant workers, and victims of radiation accidents.Materials and Methods:In this study, an assay for assessing radiation dose based on the induction of apoptosis in human T-lymphocytes was done to examine T-lymphocyte cells isolated from the fresh blood of 16volunteers, cultured and exposed to gamma rays. Radiation-induced apoptosis (RIA) was assessed by flow cytometric identification of cells displaying apoptosis-associated DNA condensation.Results:Dose-response experiments showed that at 2Gy dose level of radiotherapy programs, the RIA frequency was significantly above control. Apoptotic levels significantly depend on the dose of radiation rather than the donor.Conclusion:The results demonstrate the potential use of this assay as a biological indicator of radiation toxicity, optimizing patient dose in radiotherapy and biological dosimetry process.

Assessment of Some Immune Parameters in Occupationally Exposed Nuclear Power Plants Workers: Flowcytometry Measurements of T, B, NK and NKT Cells

The purpose of this article is to analyze the results of a 10-year survey of the radiation effects of some immune parameters of occupationally exposed personnel from the Nuclear Power Plant “Kozloduy”, Bulgaria. 438 persons working in NPP with cumulative doses between 0.06 mSv and 766.36mSv and a control group with 65 persons were studied. Flow cytometry measurements of T, B, natural killer (NK) and natural killer T (NKT) cell lymphocyte populations were performed. Data were interpreted with regard to cumulative doses, length of service and age. The average values of the studied parameters of cellular immunity were in the reference range relative to age and for most of the workers were not significantly different from the control values. Low doses of ionizing radiation showed some trends of change in the number of CD3+CD4+ helper-inducer lymphocytes, CD3+ CD8+ and NKT cell counts. The observed changes in some of the studied parameters could be interpreted in terms of adaptation processes at low doses. At doses above 100–200 mSv, compensatory mechanisms might be involved to balance deviations in lymphocyte subsets. The observed variations in some cases could not be attributed only to the radiation exposure because of the impact of a number of other exogenous and endogenous factors on the immune system.

Exploring the relationship between safety culture and safety performance in U.S. nuclear power operations

How do nuclear power plant workers, within a single national culture, perceive safety culture within their organizations? What is the relationship between safety culture and other indicators of safety? Is the construct of safety culture useful for predicting future plant performance? These questions were addressed in the current study using a survey administered to a sample of personnel at 97% of the nuclear power plants in the United States, resulting in 2876 responses from 63 nuclear power plant sites. Exploratory and confirmatory factor analysis revealed a multi-factor structure to the safety culture survey. For each nuclear power plant, the mean score for the total survey results and the factor means were correlated with organization-level performance indicators both concurrently and one year following the survey administration. Correlations suggested meaningful, statistically significant relationships between safety culture, as measured by the survey, and multiple nuclear power plant performance indicators. This study presents a unique look at safety culture across the United States nuclear power industry and takes a critical step toward establishing that safety culture is empirically related to safety performance.

Applicability test of methods for discrimination between external and internal contamination using an ORTEC whole body counter

Whole-body counters (WBCs) are generally used for monitoring internal radioactive contamination of radiation workers in nuclear power plants. However, it has been found that external contamination is occasionally counted as internal contamination. The previous study was conducted to provide guidance on measuring the exact internal radioactivity using a Canberra WBC. However, there is strong need to verify the application of the previous study to whole-body counting using a different type of WBC, ORTEC StandFAST II. Thus, in this study, several experiments were conducted focusing on the discrimination between external and internal contamination. Finally, it was found that counts from the front and back are still effective to distinguish external contamination from internal contamination for whole-body counting.