Nuclear Power Plant Workers Research Articles

Effects of personal states and personality traits on work performance of commissioning workers in nuclear power plants

Effects of personal states and personality traits on work performance of commissioning workers in nuclear power plants

The relationship between human error and occupational stress of commissioning workers in nuclear power plants: the mediating effects of anxiety

ABSTRACT The commissioning of a nuclear power plant (NPP) is a high-intensity job with severe consequences in the event of accidents. Commissioning workers are exposed to both mentally and physically demanding conditions, factors that may impose an elevated probability of human errors. This study aimed to explore the relationship between occupational stress (OS) and human error (HE) among commissioning workers in NPPs and verify whether anxiety mediates this relationship. A cross-sectional, descriptive and analytic study was carried out among 215 commissioning workers across three NPP commissioning sites in China, three questionnaires were used to collect data on OS, anxiety, and HE. The analyses were performed using the Process 3.0 macro in SPSS to verify the mediation effect. This study highlights the need for individual stress and anxiety management by providing managers with insight into the mechanism of anxiety in relation to OS and HE, which can effectively reduce the probability of HE and improve the safety of nuclear power systems.

ВІДЧУТТЯ МІСЦЯ ЯК ЧИННИК СТІЙКОСТІ ГРОМАДИ МІСТА (ДОСЛІДЖЕННЯ НА ПРИКЛАДІ МІСТА СЛАВУТИЧ, УКРАЇНА)

The importance of the sense of place issue lies in its ability to enhance the community's resilience in addressing current situational and strategic tasks related to the cohesion of residents in the face of natural, social, or military challenges. To achieve a sense of place on a collective level, it is necessary to appeal to the unique and important characteristics of a place for its residents. This includes an authentic spirit and character of place that can influence the cognitive, behavioral, and emotional dimensions of the relationship between people and places. The research goal is to investigate the influence of a sense of place on the development of a cohesive and resilient community, using the city of Slavutych as an example. Despite facing various challenges, the city has consistently demonstrated a strong sense of unity and local patriotism based on past experiences. The community of Slavutych experienced the most recent challenge during the blockade and temporary occupation in March 2022, when the city was able to drive out the russian invaders as a result of a peaceful rally, self-organization of residents, and silent resistance by Chornobyl nuclear power plant workers. This reactive participation led to an active rethinking of local meanings and contexts of sense of place. Using the example of Slavutych city, we demonstrate how two groups of factors of a sense of place (physical features and cognitive and perceptual factors) determine the infrastructural, economic, ecological, institutional, social and competence dimensions of community resilience. Based on the results of a long-term study of the city using methods of observation, surveys, in-depth interviews, and expert analysis, the article emphasizes that community cohesion manifests itself differently in peacetime and during wartime challenges. However, in both cases, it is based on a strong sense of place, solidarity, and the establishment of informal social networks. Clearly understanding the uniqueness and exclusivity of Slavutych as an ideal satellite city of a nuclear power plant, the youngest and most comfortable city in Ukraine, we believe that community cohesion during the war is a typical phenomenon of national scale for all Ukrainian communities.

High-radiation-exposure work in Korean pressurized water reactors

Owing to strict radiation safety management in Korean nuclear power plants (NPPs), most radiation workers receive very low radiation doses, even lower than the annual dose limit for the general public. However, the occupational dose distribution indicates that some Korean NPP workers receive a relatively higher dose than the average dose. This inequity in radiation exposure could be reduced by providing customized radiation protection measures, such as dose constraints, to workers receiving relatively higher doses. In this study, dose normalization was performed to identify the highest radiation exposure work in Korean pressurized water reactors (PWRs). The results show that most of the occupational exposure in Korean PWRs occurs during the planned maintenance period. Finally, the three highest radiation exposure tasks in Korean PWRs were identified: nozzle dam installation and removal, eddy current testing, and man-way opening and closing.

Radiation safety assessments for radioactive concrete recycling workers and residents

Carried out was the assessment of the radiation safety for the recycling workers of the radioactive concrete generated from nuclear power plants and nearby residents. Decommissioning of a nuclear power plant with an electric output of 1000 MW generates approximately 500,000 tons of concrete waste. It is important to reduce the volume of concrete waste to reduce the costs of decommissioning projects. For this purpose, the low-level radioactive cement powder from bioshield concrete is recycled as a solidifying agent. The number of radioactive concrete waste drums to be disposed is reduced by extracting cement from the radioactive concrete and using it as a solidifying agent, rather than using cement from general industrial waste. Various exposure scenarios exist, and it is necessary to evaluate the radiation dose in each scenario. In this study, seven scenarios were selected and evaluated. The radioactive exposure to facility workers, nuclear power plant workers, and landfill management workers is within the annual dose limit, even if they work 2000 h per year. A loader can work close to the drum for 90–93 h per year, and a truck driver can drive 621 one-way trucks per year. Dose evaluations for road users and residents after landfill closure showed that both had values far below the dose limit for the public. Bioshield concrete recycling was confirmed to be radiologically safe in all scenarios if certain conditions were satisfied. Thus, this study showed that cement powder from bioshield concrete could be used safely without exceeding the radiation safety limits for workers and the public when recycling concrete.

Moon, Mars and Minds: Evaluating Parkinson’s disease mortality among U.S. radiation workers and veterans in the million person study of low-dose effects

BackgroundRadiation is one of the most important stressors related to missions in space beyond Earth’s orbit. Epidemiologic studies of exposed workers have reported elevated rates of Parkinson’s disease. The importance of cognitive dysfunction related to low-dose rate radiation in humans is not defined. A meta-analysis was conducted of six cohorts in the Million Person Study (MPS) of low-dose health effects to learn whether there is consistent evidence that Parkinson’s disease is associated with radiation dose to brain. Materials and methodsThe MPS evaluates all causes of death among U.S. radiation workers and veterans, including Parkinson’s disease. Systematic and consistent methods are applied to study all categories of workers including medical radiation workers, industrial radiographers, nuclear power plant workers, atomic veterans, and Manhattan Projects workers at the Los Alamos National Laboratory and at Rocky Flats. Consistent methods for all cohorts are used to estimate organ-specific doses and to obtain vital status and cause of death. ResultsThe meta-analysis include 6 cohorts within the MPS, consisting of 517,608 workers and 17,219,001 person-years of observation. The mean dose to brain ranged from 6.9 to 47.6 mGy and the maximum dose from 0.76 to 2.7 Gy. Five of the 6 cohorts revealed positive associations with Parkinson’s disease. The overall summary estimate from the meta-analysis was statistically significant based on 1573 deaths due to Parkinson’s disease. The summary excess relative risk at 100 mGy was 0.17 (95% CI: 0.05; 0.29). ConclusionsParkinson’s disease was positively associated with radiation in the MPS cohorts indicating the need for careful evaluation as to causality in other studies, delineation of possible mechanisms, and assessing possible implications for space travel as well as radiation protection guidance for terrestrial workers.

Experimental Investigation of Cobalt Deposition on 304 Stainless Steel in Borated and Lithiated High-Temperature Water.

The radioactive corrosion products 58Co and 60Co in the primary loops of pressurized water reactors (PWRs) are the main sources of radiation doses to which workers in nuclear power plants are exposed. To understand cobalt deposition on 304 stainless steel (304SS), which is the main structural material used in the primary loop, the microstructural characteristics and chemical composition of a 304SS surface layer immersed for 240 h in borated and lithiated high-temperature water containing cobalt were investigated with scanning electron microscopy (SEM), X-ray diffraction (XRD), laser Raman spectroscopy (LRS), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectrometry (GD-OES), and inductively coupled plasma emission mass spectrometry (ICP-MS). The results showed that two distinct cobalt deposition layers (an outer layer of CoFe2O4 and an inner layer of CoCr2O4) were formed on the 304SS after 240 h of immersion. Further research showed that CoFe2O4 was formed on the metal surface by coprecipitation of the iron preferentially dissolved from the 304SS surface with cobalt ions from the solution. The CoCr2O4 was formed by ion exchange between the cobalt ions entering the metal inner oxide layer and (Fe, Ni) Cr2O4. These results are useful in understanding cobalt deposition on 304SS and have a certain reference value for exploring the deposition behavior and mechanism of radionuclide cobalt on 304SS in the PWR primary loop water environment.

The Predictors of Unsafe Behaviors among Nuclear Power Plant Workers: An Investigation Integrating Personality, Cognitive and Attitudinal Factors.

Unsafe behaviors, such as violations and human errors, have long been recognized as the main causes of accidents in nuclear power plants (NPPs). However, personal factors that influence unsafe behaviors among NPP workers have not been well examined, especially in an integrated model. This study proposes an integrated contextual mediated model to examine personality, cognitive and attitudinal predictors of unsafe behaviors among commissioning workers at NPPs. The model was verified using structural equation modeling technique with survey data from 177 commissioning workers in two Chinese NPPs. Results show that personality traits (i.e., conscientiousness, neuroticism, openness and agreeableness), executive function and safety attitudes exerted significant effects on unsafe behaviors. In addition, the effects of agreeableness and executive function were partly mediated by safety attitudes. Both conscientiousness and neuroticism indirectly influenced unsafe behaviors through the mediating role of executive function. The findings shed light on the design of evidence-based interventions for safety performance in NPPs.

Rao-combined artificial bee colony algorithm for minimum dose path planning in complex radioactive environments

Nuclear power plant workers inevitably work in a radiation environment. Minimum dose path planning becomes an important issue in ensuring that they receive as little radiation as possible. However, a work environment with complex obstacles or narrow passages makes the problem of finding the path with the minimum dose more difficult. In this paper, we propose a meta-heuristic method to solve this problem. An algorithm called Rao-combined artificial bee colony (RABC) is proposed with a novel obstacle detour technique. The RABC algorithm combines the directional solution update method of the Rao algorithm with the traditional ABC algorithm to further improve performance. To evaluate the effectiveness of the proposed method, three hypothetical environments are simulated. In the first hypothetical environment where there are no obstacles and many radiation sources are scattered, the meta-heuristic algorithms, PSO, ABC and RABC are compared, and in the second hypothetical environment with narrow passages and obstacles, the grid-based A* algorithm and the sampling-based RRT* algorithm are used for comparison with RABC. The third hypothetical environment is a complex environment where many radiation sources and obstacles are distributed and there are narrow passages. In this case, the proposed algorithm is compared with the Dijkstra algorithm and the GB-RRT* algorithm, which is known as one of the best in obstacle avoidance. Experimental results show that the proposed method is superior in exploration and exploitation, convergence and robustness compared to other meta-heuristic algorithms as well as grid-based or sampling-based algorithms.

Organ dose reconstruction for the radiation epidemiological study of Korean radiation workers: The first dose evaluation for the Korean Radiation Worker Study (KRWS)

The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, Hp(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting Hp(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

Sickness Absence in the Kursk Nuclear Power Plant Workers as an Element of the Digital Twin Concept in Occupational Medicine

Introduction: A multifactorial analysis of the causes of morbidity and preventive measures provides an opportunity to build a risk prediction model for sickness absence in the working population, thereby reducing production and healthcare costs. Objective: A retrospective analysis of sickness absence in workers of the Kursk Nuclear Power Plant exposed to a combination of occupational risk factors in the year 2020. Materials and methods: We analyzed sickness absence rates in the workers in terms of the ICD-10 nomenclature based on data of the Russian Statistical Observation Form No. 16-VN and established the number of episodes of sickness absence per employee as a relative indicator independent of the size of the groups under study. Results: The highest sickness absence rates per 100 employees were estimated for workers of the Training Center and Design and Technology Department (73.1 episodes each), the Hydroshop (68.6) and Transportation Department (65.5). In the Radioactive Waste Treatment Shop and the first and second Reactor Shops, these rates were 53, 43.9, and 33.9 per 100 employees, respectively. The mean duration of an episode of sickness absence in all divisions of the nuclear power plant was 13–15.4 days and its most frequent causes were, similar to the Kursk Region and the Russian Federation as a whole, diseases of the respiratory and musculoskeletal systems, injuries and poisonings. Conclusions: It is important to develop a risk-based approach in occupational medicine. To establish a cause-and-effect relationship for loss of health among nuclear industry workers, we propose to create a digital platform (a digital twin of an employee) enabling prediction of the time, cause, risk of a disease and/or disability, and prerequisites for its mitigation.

Radiation exposure to the lens of the eye for Japanese nuclear power plant workers

In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.

ANALYSIS OF PROSPECTS OF APPLICATION OF POLYMERIC MATERIALS FOR THE MANUFACTURE OF NUCLEAR PROTECTIVE CLOTHING

The article is devoted to identifying the main ways to improve the design and manufacture of clothing for nuclear power plant workers to ensure the competitiveness of domestic products. The scientific novelty of the work is that it further developed the issue of systematization of the range of nuclear protective clothing, which identified ways to improve its design processes in the domestic garment industry. The practical significance of the work lies in the use of polymeric materials in the designed methods of processing the components of the developed suit of nuclear protective clothing. The authors analyze the current state of research in the design and manufacture of nuclear protective clothing. Depending on the work performed, the range of nuclear protective clothing is considered from the standpoint of the materials used. The world leaders producing nuclear protective clothing are 3M; Lakeland; DuPont; Honeywell; Microgard; Delta Plus; Kappler; Casco; MATISEC; VersarPPS. According to the results of the analysis of the range of nuclear protective clothing, it is determined that the vast majority of manufacturers focus on the materials from which nuclear protective clothing is made to protect against radiation pollution and other harmful factors. As a result of scientific research, the basic approaches of the world leaders-manufacturers of nuclear protective clothing concerning the connection of details of products are defined. A database of seams used to make nuclear protective clothing has been formed. Among the variety of protective clothing, the basic design and technological solutions of protective clothing are identified as those that most fully protect against certain types of hazards for various industries in terms of passive methods of employee protection. The selected range of basic protective clothing includes suits and varieties of pants and jackets. A men’s jacket as a part of nuclear protective clothing is proposed, and methods of processing the product’s main components based on the use of polymeric materials are improved. Sealing the joints of the product parts using a film with a polymer coating is suggested. The authors have formulated requirements for materials used for the manufacture of suits for nuclear power plant workers: indicators of physical and mechanical, and physicochemical properties of materials for manufacturing white suits.

Chromosome Damage in Relation to Recent Radiation Exposure and Radiation Quality in Nuclear Power Plant Workers.

Ionizing radiation is a well-known carcinogen that causes genomic instability. However, the biological and carcinogenetic effects of occupational radiation exposure at low doses have not been extensively studied. The aim of this study was to assess chromosomal instability in power plant workers exposed to occupational radiation at low doses in South Korea. Chromosomal aberrations in the lymphocytes of 201 nuclear power plant workers and 59 sex-matched controls were measured. Chromosomal aberrations in the lymphocytes of 201 nuclear power plant workers (mean age: 41.4 ± 10.0 years) and 59 sex-matched controls (mean age: 47.2 ± 6.0 years) were measured. A total of 500 metaphases for each subject were scored randomly. The means of recent 1.5-year, recent 5.5-year, and cumulative exposed radiation doses among workers were 8.22 ± 7.0 mSv, 30.7 ± 22.0 mSv, and 158.8 ± 86.1 mSv, respectively. The frequency of chromosome-type and chromatid-type aberrations was significantly higher in workers than that in the control group (p < 0.001), and the frequency of chromosome-type aberrations among workers increased in a radiation dose-dependent manner (τ = 0.16, p = 0.005). Poisson regression analyses revealed that chromosome-type aberrations were significantly associated with recent 1.5-year dose after adjusting for confounding variables such as age, smoking, and alcohol intake, even when only the exposed worker was considered. Frequency of multi-aberrant cells (two or more chromosome aberrations within a cell) increased according to cumulative neutron exposure. Our study demonstrates that chromosome damage can be induced in nuclear power plant workers occupationally exposed to ionizing radiation at low doses below the occupational permissible dose limit. Furthermore, an increase in multi-aberrant cells may provide evidence for chronic neutron exposure in nuclear power plant workers. This study was performed to obtain baseline data for a surveillance program of workers occupationally exposed to ionizing radiation long-term.

Dose rate distribution measuring method using personal dosimeters and localization devices

ABSTRACT To further reduce the radiation exposure of nuclear power plant workers, we propose a new method that enables measurements of radiation distribution. This method uses a worker’s position detection device and an electronic personal dosimeter worn by the worker. The dose rate distribution of γ-rays can be measured with high resolution without increasing the workload of radiation management people. To confirm the feasibility of this concept, a test system was built and measurement tests were conducted in an area where a radiation source was located. The dose rate distribution measurement capability of this system produced results comparable to those predicted by a simulated test, with a difference within 4.0 μSv/h. Moreover, we confirmed the applicability of the proposed method to nuclear power plants on the basis of a rough evaluation for an on-site work situation.

Framework for the development of guidelines for nuclear power plant decommissioning workers based on risk information

In nuclear power plant decommissioning, it is essential to reduce radioactive waste while, in the reducing process, radiation exposure for the decommissioning workers is inevitable. Therefore, a guideline development framework for decommissioning workers based on radiation safety is suggested in this study. In a previous study, a risk assessment for the decommissioning worker was conducted. Based on the risk assessment methodology, the framework is developed. First, all factors that affect the radiation safety of the decommissioning workers are analyzed. Moreover, the factors are classified to each level, distinguished by controllable conditions and radiation safety influence. Factors in certain levels are analyzed through sensitivity study, and guidelines from significant factors are obtained. In addition, by dividing the workers’ exposure into inevitable and additional, limitations for each exposure are suggested. Consequently, the practical instructions for the workers are conducted. Therefore, the guidelines suggested in the framework are intuitive and quantitative to apply in decommissioning. This study improves the radiation safety of workers in nuclear power plants.

Contribution of radiation education to anxiety reduction among Fukushima Daiichi Nuclear Power Plant workers: a cross sectional study using a text mining method.

The purpose of this study is to investigate the frequency of education, knowledge of radiation and workplace anxiety of Fukushima Daiichi Nuclear Power Plant (FDNPP) workers and to analyze what type of words are used for anxiety with a text mining method. An original questionnaire survey was given to FDNPP workers, and a text mining method was used to extract information from free-entry fields. The questionnaires were collected from 1135 workers (response rate: 70.8%). It was found that when workers receive education on radiation, the increased knowledge helps to reduce their anxiety. Among the 1135 workers, 92 of 127 completed the free-entry field with valid entries. Seventy-one words were extracted by the text mining method. The words used differed depending on the degree of anxiety. The text mining method revealed information about the presence or absence of radiation anxiety and the subjects’ working environment and background.

Type and duration of emergency recovery work and its longitudinal effects on mental health symptoms among Fukushima Daiichi Nuclear Power Plant workers: The Fukushima NEWS project study

BackgroundThe Fukushima Nuclear Energy Workers' Support study showed the Fukushima nuclear disaster caused psychological distress in the workers, with higher rates of post-traumatic stress responses (PTSR). To understand how the type and duration of emergency recovery work performed immediately following this disaster impacted workers’ psychological status, a longitudinal analysis was conducted with 4-year follow-up data since 2011. MethodFukushima Daiichi nuclear power plant workers were assessed annually with general psychological distress (GPD) and PTSR questionnaires between 2011 and 2014. Combined, 697 Fukushima Daiichi plant workers provided baseline GPD and PTSR in 2011 and their record of working days for approximately one month immediately following the disaster. The relationship between type of emergency recovery work, working days immediately following the disaster, and psychological distress over four years was analyzed using a mixed effects logistic regression model. ResultsAt baseline, GPD and PTSR scores were significantly higher in nuclear power plant workers who worked 3–5 days immediately following the disaster compared to those who worked only 0–2, particularly in the field engineer subgroup. The effect of working days on GPD remained for over a year, and the impact on PTSR remained significant throughout the four years of observation after the disaster. ConclusionsThe Fukushima Daiichi plant field engineers showed significantly higher psychological distress than other workers. The impact of emergency recovery work on psychological distress persisted for over one year, but PTSR in field engineer workers remained significantly elevated four years after the disaster.

Mortality from leukemia, cancer and heart disease among U.S. nuclear power plant workers, 1957–2011

Background The aim of the Million Person Study of Low-Dose Health Effects (MPS) is to examine the level of radiation risk for chronic exposures received gradually over time and not acutely as was the case for the Japanese atomic bomb survivors. Nuclear power plant (NPP) workers comprise nearly 15 percent of the MPS. Leukemia, selected cancers, Parkinson’s disease, ischemic heart disease (IHD) and other causes of death are evaluated. Methods and material The U.S. Nuclear Regulatory Commission’s Radiation Exposure Information and Reporting System (REIRS) and the Landauer, Inc. dosimetry databases identified 135,193 NPP workers first monitored 1957–1984. Annual personal dose equivalents [Hp(10)] were available for each worker. Radiation records from all places of employment were sought. Vital status was determined through 2011. Mean absorbed doses to red bone marrow (RBM), esophagus, lung, colon, brain and heart were estimated by adjusting the recorded Hp(10) for each worker by scaling factors, accounting for exposure geometry and energy of the incident gamma radiation. Standardized mortality ratios (SMR) were calculated. Radiation risks were estimated using Cox proportional hazards models. Results Nearly 50% of workers were employed for more than 20 years. The mean duration of follow-up was 30.2 y. Overall, 29,124 total deaths occurred, 296 from leukemia other than chronic lymphocytic leukemia (CLL), 3382 from lung cancer, 140 from Parkinson’s disease and 5410 from IHD. The mean dose to RBM was 37.9 mGy (maximum 1.0 Gy; percent >100 mGy was 9.2%), 43.2 mGy to lung, 43.7 mGy to colon, 33.2 mGy to brain, and 43.9 mGy to heart. The SMRs (95% CI) were 1.06 (0.94; 1.19) for leukemia other than CLL, 1.10 (1.07; 1.14) for lung cancer, 0.90 (0.76; 1.06) for Parkinson’s disease, and 0.80 (0.78; 0.82) for IHD. The excess relative risk (ERR) per 100 mGy for leukemia other than CLL was 0.15 (90% CI −0.001; 0.31). For all solid cancers the ERR per 100 mGy (95% CI) was 0.01 (–0.03; 0.05), for lung cancer −0.04 (–0.11; 0.02), for Parkinson’s disease 0.24 (–0.02; 0.50), and for IHD −0.01 (–0.06; 0.04). Conclusion Prolonged exposure to radiation increased the risk of leukemia other than CLL among NPP workers. There was little evidence for a radiation association for all solid cancers, lung cancer or ischemic heart disease. Increased precision will be forthcoming as the different cohorts within the MPS are combined, such as industrial radiographers and medical radiation workers who were assembled and evaluated in like manner.

Mortality among medical radiation workers in the United States, 1965–2016

Background Estimates of radiation risks following prolonged exposures at low doses and low-dose rates are uncertain. Medical radiation workers are a major component of the Million Person Study (MPS) of low-dose health effects. Annual personal dose equivalents, H P(10), for individual workers are available to facilitate dose-response analyses for lung cancer, leukemia, ischemic heart disease (IHD) and other causes of death. Materials and methods The Landauer, Inc. dosimetry database identified 109,019 medical and associated radiation workers first monitored 1965–1994. Vital status and cause of death were determined through 2016. Mean absorbed doses to red bone marrow (RBM), lung, heart, and other organs were estimated by adjusting the recorded H P(10) for each worker by scaling factors, accounting for exposure geometry, the energy of the incident photon radiation, sex of the worker and whether an apron was worn. There were 4 exposure scenarios: general radiology characterized by low-energy x-ray exposure with no lead apron use, interventional radiologists/cardiologists who wore aprons, nuclear medicine personnel and radiation oncologists exposed to high-energy photon radiation, and other workers. Standardized mortality ratio (SMR) analyses were performed. Cox proportional hazards models were used to estimate organ-specific radiation risks. Results Overall, 11,433 deaths occurred (SMR 0.60; 95%CI 0.59,0.61), 126 from leukemia other than chronic lymphocytic leukemia (CLL), 850 from lung cancer, and 1654 from IHD. The mean duration of monitoring was 23.7 y. The excess relative rate (ERR) per 100 mGy was estimated as 0.10 (95% CI −0.34, 0.54) for leukemia other than CLL, 0.15 (0.02, 0.27) for lung cancer, and −0.10 (–0.27, 0.06) for IHD. The ERR for lung cancer was 0.16 (0.01, 0.32) among the 55,218 male workers and 0.09 (–0.19, 0.36) among the 53,801 female workers; a difference that was not statistically significant (p-value = 0.23). Conclusions Medical radiation workers were at increased risk for lung cancer that was higher among men than women, although this difference was not statistically significant. In contrast, the study of Japanese atomic bomb survivors exposed briefly to radiation in 1945 found females to be nearly 3 times the radiation risk of lung cancer compared with males on a relative scale. For medical workers, there were no statistically significant radiation associations with leukemia excluding CLL, IHD or other specific causes of death. Combining these data with other cohorts within the MPS, such as nuclear power plant workers and nuclear submariners, will enable more precise estimates of radiation risks at relatively low cumulative doses.