HEALTH IN THE SYSTEM OF VALUES OF THE POPULATION OF THE SURVEILLANCE ZONES NUCLEAR POWER PLANTSS

OBJECTIVE

to determine the place of health in the system of values of the population of the surveillance zone (SZ)of nuclear power plants (NPPs) and its importance in the perception of emergency risks (ER).

MATERIALS AND METHODS

To determine the place of health in the value system, a survey of the able-bodied popula-tion of satellite cities of Rivne (RNPP) and South Ukrainian (SUNPP) nuclear power plants was conducted using non-repetitive sampling, where the sampling error does not exceed 7,0 %. The motivational and behavioral componentthat determined health in the individual hierarchy of values of the subject according to the questionnaireBerezovskaya R. A. was studied. Statistical and mathematical methods were used in the research process.

RESULTS

The array of respondents was conditionally divided into 4 groups according to their attitude to humanhealth. And the group where a person's life position is focused exclusively on health is the most common - 77,0 %.Group IV, which wants to live without limiting itself, is 8,1 %. The component integrity of values-goals and values-means among the urban population of the SZ of both nuclear power plants is the same: the main goal in life is health,happy family life, and as a means - perseverance, diligence and health. Goal values in groups I and IV have somedifferences: in the first group of respondents the main goal in life is health, and in the fourth, where a person's lifeguidelines exclude any restrictions - a happy family life. Values for these populations have some differences, but inboth groups health appears to be the main means to an end. There is a close correlation between the core of termi-nal values and the average indicators of the state of concern about the risk of emergencies.

CONCLUSIONS

Identified hierarchy of values: a group of stable dominant values; average status values; group of leastsignificant values. The values of the highest status among the values-goals are - health, happy family life and inte-resting work. Most respondents plan to achieve them through values such as «health», «perseverance and hardwork». There is a close correlation between the core of terminal values and the average indicators of the state ofconcern about the risk of emergencies.

Introduction of a method to calculate cumulative age- and gender-specific lifetime attributable risk (LAR) of cancer in populations after a large-scale nuclear power plant accident

The effect of age and gender in risk estimates related to long-term residence in areas contaminated by nuclear power plant fallout was evaluated by applying the lifetime attributable risk (LAR) concept to an existing exposure model that was previously used for cumulative effective dose estimates. In this study, we investigated the influence of age distribution on the number of cancer cases by applying five different age distributions from nuclear power-producing countries (India, Japan, South Korea, and the United States), and Egypt because of intentions to develop nuclear power. The model was also used to estimate the effective dose and gender-specific LAR as a function of time after fallout for the offspring of the population living in 137Cs fallout areas. The principal findings of this study are that the LAR of cancer incidence (excluding non-fatal skin cancers) over 70 y is about 4.5 times higher for newborn females (5.4% per MBq m-2 of initial 137Cs ground deposition) than the corresponding values for 30 y old women (1.2% per MBq m-2 137Cs deposition). The cumulative LAR for newborn males is more than 3 times higher (3.2% versus 1.0% per MBq m-2 137Cs deposition). The model predicts a generally higher LAR for women until 50 y of age, after which the gender difference converges. Furthermore, the detriment for newborns in the fallout areas initially decreases rapidly (about threefold during the first decade) and then decreases gradually with an approximate half-time of 10-12 y after the first decade. The age distribution of the exposed cohort has a decisive impact on the average risk estimates, and in our model, these are up to about 65% higher in countries with high birth rates compared to low birth rates. This trend implies larger average lifetime attributable risks in countries with a highly proportional younger population. In conclusion, the large dispersion (up to a factor of 4 between newborns and 30 y olds) in the lifetime detriment per unit ground deposition of 137Cs over gender and age in connection with accidental nuclear releases justifies the effort in developing risk models that account for the higher radiation sensitivity in younger populations.

A study of the radiological baseline conditions around the planned Sinop (Turkey) nuclear power plant using the mapping method

This study makes a first attempt at a detailed estimation of the background radioactivity level and its distribution at the Sinop nuclear power plant site. The activity concentration levels of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs radionuclides in soil samples collected from 88 locations around Sinop Province, Turkey, in November 2016, were measured using gamma spectrometry. The distributions of radionuclide levels obtained from the results were evaluated using a geostatistical method, and the estimated radiation levels were determined using the ordinary kriging (OK) method, which is the best linear unbiased estimator (BLUE) for unmeasured points. Estimates of distribution results were evaluated using cross-validation diagrams, and it was shown that the OK method could predict radiological distributions for appropriate criteria. Finally, using the kriging parameters, distributions of radiation levels for the entire work area were mapped at a spatial resolution of 100 × 100 m². These maps show that the natural radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) are distributed at higher levels to the southeast of Sinop than in the other regions, and the activity of an artificial radionuclide (¹³⁷Cs) is high in the interior and northern sections.

Estimated Thyroid Inhalation Doses Based on Body Surface Contamination Levels of Evacuees After the Fukushima Daiichi Nuclear Power Plant Accident

Doses of inhaled radionuclides received during evacuation might be correlated with amounts of those radionuclides on an evacuee's body surface. The purpose of the present study was to estimate thyroid equivalent doses based on body surface contamination measured with a Geiger-Mueller survey meter on 2,087 evacuees from Tomioka, Okuma, Futaba, Naraha, Namie, Minamisoma, and other municipalities in Japan. The measurement value in cpm was translated into Bq cm according to the radionuclide composition obtained by germanium gamma-spectrometry analyses of two persons' clothing. Thyroid equivalent dose by inhalation was estimated by two-dimensional Monte Carlo simulation based on the distribution of body surface radionuclide concentration and a uniform distribution of deposition velocity. For evacuees exposed twice on 12 and 15 March, the mean, median, and 90th percentile of inhalation thyroid equivalent dose for 1-y-old children were 21.4 mSv, 4.7 mSv, and 40.1 mSv for the Namie group; 7.3 mSv, 5.1 mSv, and 14.8 mSv for the Minamisoma group; and 2.3 mSv, 0.5 mSv, and 4.0 mSv for the group comprising Tomioka, Okuma, Futaba, and Naraha. These estimates are smaller than estimates in the United Nations Scientific Committee on the Effects of Atomic Radiation 2013 report but closer to estimates based on direct thyroid I measurement or indirect estimates based on Cs measurements made with a whole-body counter under the assumption that the ratio of I to Cs is 3.8.

ANALYSIS OF THE RADIOLOGICAL SAFETY CONTROL LEVEL VERSUS THE EXPOSURE OF RADIATION WORKERS IN SOUTH KOREA FROM 2008-17

In this study, the radiation exposure of workers at workplaces registered and licensed between 2008 and 2017 for the production/sale/use of radioactive isotopes (RI) and radioactive generators (RG) was analysed to evaluate the quality of radiation safety management controls in use. The number of facilities using RIs increased by ~26% from 2008 to 2017 whereas the number of facilities using RGs increased by ~166% over the same period. There were 33 029 radiation workers in all fields in 2008, and the number increased by ~32% to 43 467 by 2017. However, the collective effective dose of radiation received by workers decreased in all industries except for those working in nuclear power plants. In other words, the quality of radiation safety management improved over that same time period due to the systematic, continuous introduction of safety mechanisms by the regulatory authority.

Contested credibility economies of nuclear power in India

STS scholars studying anti-nuclear activism in the context of nations in the Global North have observed the critical role of science to mediate relations of domination and resistance. Through a historical examination of anti-nuclear activism in India, this article investigates the instrumentalization of science as a liberal democratic rationality. In doing so, the article shows how elite Indian activists - many of whom are scientists, engineers, journalists and academic professionals - will never be seen as scientifically knowledgeable in nuclear matters, because of their non-state educational pedigrees. If activists cannot hold the state accountable through science, they have attempted to anticipate what other kinds of arguments and modes of contention may gain traction. As such, they have deployed more 'guerilla' tactics grounded in bureaucratic rationalities in the hopes of installing themselves as alternate sources of expertise in India's nuclear landscape.

An approach to identifying the relative importance of different radionuclides in ecological radiological risk assessment: Application to nuclear power plant releases

There is a need to prioritise the requirements for data to assess the radiological risk for fauna and flora, as inevitable large data gaps occur due to the large number of combinations of radionuclides and organisms for which doses need to be assessed. The potentially most important dose-forming radionuclide-pathways combinations need to be identified to optimize filling these gaps. Few attempts have been made to classify the importance of isotopes with regard to radiation protection of the environment. A hierarchical approach is described here for radionuclides that are potentially present in generic ecosystems (freshwater, marine or terrestrial) and is applied for scenarios considering ecologically relevant chronic exposure. In each ecosystem, the top ten radionuclides that may contribute to doses were identified using a qualitative Chronic Hazard Index. Including quantitative aspects by incorporating discharge quantities changed the priority list, and increased the relative importance of radionuclides contributing most to the authorized releases of nuclear facilities (¹⁴C and ³H followed by ⁶⁰C). The potentially most important dose-contributing radionuclides in the framework of environmental radiation protection under a chronic exposure situation included isotopes of about 20 elements. The five most important in order of decreasing importance were: carbon, hydrogen, caesium, cobalt and americium. Consideration of acute exposure situations was hampered by data gaps that were even greater than that for chronic exposure situations, so it was only possible to consider the feasibility of developing a consistent approach.

Reanalysis of Epidemiological Investigation of Cancer Risk among People Residing near Nuclear Power Plants in South Korea

Background: A 20-year follow-up study on cancer incidence among people living near nuclear power plants in South Korea ended in 2011 with a finding of significantly, but inconsistently, elevated thyroid cancer risk for females. Reanalysis of the original study was carried out to examine the dose-response relationship further, and to investigate any evidence of detection bias. Methods: In addition to replicating the original Cox proportional hazards models, nested case-control analysis was carried out for all subjects and for four different birth cohorts to examine the effects of excluding participants with pre-existing cancer history at enrollment. The potential for detection bias was investigated using the records of medical utilization and voluntary health checks of comparison groups. Results: The overall risk profile of the total sample was similar to that of the original study. However, in the stratified analysis of four birth cohorts, the cancer risk among people living near nuclear power plants became higher in younger birth cohorts. This was especially true for thyroid cancers of females (hazard ratio (HR) 3.38) and males (HR 1.74), female breast cancers (HR 2.24), and radiation-related cancers (HR 1.59 for males, HR 1.77 for females), but not for radiation-insensitive cancers (HR 0.59 for males, HR 0.98 for females). Based on medical records and health check reports, we found no differences between comparison groups that could have led to detection bias. Conclusions: The overall results suggest elevated risk of radiation-related cancers among residents living near nuclear power plants, controlling for the selective survival effect. This is further supported by the lack of evidence of detection bias and by records of environmental exposure from radiation waste discharge.

Mortality from Circulatory Diseases and other Non-Cancer Outcomes among Nuclear Workers in France, the United Kingdom and the United States (INWORKS)

Positive associations between external radiation dose and non-cancer mortality have been found in a number of published studies, primarily of populations exposed to high-dose, high-dose-rate ionizing radiation. The goal of this study was to determine whether external radiation dose was associated with non-cancer mortality in a large pooled cohort of nuclear workers exposed to low-dose radiation accumulated at low dose rates. The cohort comprised 308,297 workers from France, United Kingdom and United States. The average cumulative equivalent dose at a tissue depth of 10 mm [Hp(10)] was 25.2 mSv. In total, 22% of the cohort were deceased by the end of follow-up, with 46,029 deaths attributed to non-cancer outcomes, including 27,848 deaths attributed to circulatory diseases. Poisson regression was used to investigate the relationship between cumulative radiation dose and non-cancer mortality rates. A statistically significant association between radiation dose and all non-cancer causes of death was observed [excess relative risk per sievert (ERR/Sv) = 0.19; 90% CI: 0.07, 0.30]. This was largely driven by the association between radiation dose and mortality due to circulatory diseases (ERR/Sv = 0.22; 90% CI: 0.08, 0.37), with slightly smaller positive, but nonsignificant, point estimates for mortality due to nonmalignant respiratory disease (ERR/Sv = 0.13; 90% CI: -0.17, 0.47) and digestive disease (ERR/Sv = 0.11; 90% CI: -0.36, 0.69). The point estimate for the association between radiation dose and deaths due to external causes of death was nonsignificantly negative (ERR = -0.12; 90% CI: <-0.60, 0.45). Within circulatory disease subtypes, associations with dose were observed for mortality due to cerebrovascular disease (ERR/Sv = 0.50; 90% CI: 0.12, 0.94) and mortality due to ischemic heart disease (ERR/Sv = 0.18; 90% CI: 0.004, 0.36). The estimates of associations between radiation dose and non-cancer mortality are generally consistent with those observed in atomic bomb survivor studies. The findings of this study could be interpreted as providing further evidence that non-cancer disease risks may be increased by external radiation exposure, particularly for ischemic heart disease and cerebrovascular disease. However, heterogeneity in the estimated ERR/Sv was observed, which warrants further investigation. Further follow-up of these cohorts, with the inclusion of internal exposure information and other potential confounders associated with lifestyle factors, may prove informative, as will further work on elucidating the biological mechanisms that might cause these non-cancer effects at low doses.

Mortality from Circulatory Diseases and other Non-Cancer Outcomes among Nuclear Workers in France, the United Kingdom and the United States (INWORKS)

Positive associations between external radiation dose and non-cancer mortality have been found in a number of published studies, primarily of populations exposed to high-dose, high-dose-rate ionizing radiation. The goal of this study was to determine whether external radiation dose was associated with non-cancer mortality in a large pooled cohort of nuclear workers exposed to low-dose radiation accumulated at low dose rates. The cohort comprised 308,297 workers from France, United Kingdom and United States. The average cumulative equivalent dose at a tissue depth of 10 mm [Hp(10)] was 25.2 mSv. In total, 22% of the cohort were deceased by the end of follow-up, with 46,029 deaths attributed to non-cancer outcomes, including 27,848 deaths attributed to circulatory diseases. Poisson regression was used to investigate the relationship between cumulative radiation dose and non-cancer mortality rates. A statistically significant association between radiation dose and all non-cancer causes of death was observed [excess relative risk per sievert (ERR/Sv) = 0.19; 90% CI: 0.07, 0.30]. This was largely driven by the association between radiation dose and mortality due to circulatory diseases (ERR/Sv = 0.22; 90% CI: 0.08, 0.37), with slightly smaller positive, but nonsignificant, point estimates for mortality due to nonmalignant respiratory disease (ERR/Sv = 0.13; 90% CI: -0.17, 0.47) and digestive disease (ERR/Sv = 0.11; 90% CI: -0.36, 0.69). The point estimate for the association between radiation dose and deaths due to external causes of death was nonsignificantly negative (ERR = -0.12; 90% CI: <-0.60, 0.45). Within circulatory disease subtypes, associations with dose were observed for mortality due to cerebrovascular disease (ERR/Sv = 0.50; 90% CI: 0.12, 0.94) and mortality due to ischemic heart disease (ERR/Sv = 0.18; 90% CI: 0.004, 0.36). The estimates of associations between radiation dose and non-cancer mortality are generally consistent with those observed in atomic bomb survivor studies. The findings of this study could be interpreted as providing further evidence that non-cancer disease risks may be increased by external radiation exposure, particularly for ischemic heart disease and cerebrovascular disease. However, heterogeneity in the estimated ERR/Sv was observed, which warrants further investigation. Further follow-up of these cohorts, with the inclusion of internal exposure information and other potential confounders associated with lifestyle factors, may prove informative, as will further work on elucidating the biological mechanisms that might cause these non-cancer effects at low doses.

The (de)politicisation of nuclear power: The Finnish discussion after Fukushima

When the Fukushima accident occurred in March 2011, Finland was at the height of a nuclear renaissance, with the Government's decision-in-principle in 2010 to allow construction of two new nuclear reactors. This article examines the nuclear power debate in Finland after Fukushima. We deploy the concepts of (de)politicisation and hyperpoliticisation in the analysis of articles in the country's main newspaper. Our analysis indicates that Finnish nuclear exceptionalism manifested in the safety-related depoliticising and the nation's prosperity-related hyperpoliticisation arguments of the pro-nuclear camp. The anti-nuclear camp used politicisation strategies, such as economic arguments, to show the unprofitability of nuclear power. The Fukushima accident had a clear effect on Finnish nuclear policy: the government programme of 2011 excluded the nuclear new build. However, in 2014 the majority of Parliament again supported nuclear power. Hence, the period after Fukushima until 2014 could be described as continued but undermined loyalty to nuclear power.

Imaginaries of nuclear energy in the Portuguese parliament: Between promise, risk, and democracy

This article explores the evolution of the nuclear energy debate and its associated controversies in the Portuguese parliament. The analysis focuses on the dictatorial regime of the New State (from the beginning of the nuclear program in 1951 until the 1974 revolution) and on the democratic period (post-1974). Portugal, as an exporting country of uranium minerals, significantly invested in the development of a national capacity in nuclear research, but never developed an endogenous nuclear power infrastructure. Through the analysis of parliamentary debates, this article characterizes the dynamic evolution of the Portuguese sociotechnical imaginary on nuclear energy and technology interlinked with ambivalent representations, including the promise of nuclear energy as key for the constitution of a technological Nation or as prompting new sociotechnical risks.

Nuclear power debate and public opinion in Belarus: From Chernobyl to Ostrovets

The Belarusian government's decision of the last decade to build a nuclear power plant near the city of Ostrovets, in northern Belarus, has proven to be controversial, resulting in a great deal of debate about nuclear energy in the country. The debate was inevitably shaped by the traumatic event that affected Belarus - the Chernobyl nuclear accident of 1986. The Belarusian authorities have consistently promoted a positive view of nuclear energy to the population in order to overcome the so-called 'Chernobyl syndrome' and deliberately shaped nuclear risk communication. As a result, the issue of trust remains crucial in all nuclear debates in Belarus.

Commercial Nuclear Power Industry: Assessing and Meeting the Radiation Protection Workforce Needs

This paper will provide an overview of the process used by the commercial nuclear power industry in assessing the status of existing industry staffing and projecting future supply demand needs. The most recent Nuclear Energy Institute-developed "Pipeline Survey Results" will be reviewed with specific emphasis on the radiation protection specialty. Both radiation protection technician and health physicist specialties will be discussed. The industry-initiated Nuclear Uniform Curriculum Program will be reviewed as an example of how the industry has addressed the need for developing additional resources. Furthermore, the reality of challenges encountered in maintaining the needed number of health physicists will also be discussed.

Early Intake of Radiocesium by Residents Living Near the TEPCO Fukushima Dai-Ichi Nuclear Power Plant after the Accident. Part 1: Internal Doses Based on Whole-body Measurements by NIRS

The Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011 resulted in a release of radionuclides into the environment (I: 142.9 PBq, Cs:12.4 PBq). This study presents the results of internal doses to 174 residents living near the FDNPP at the time of the accident based on whole-body (WB) measurements performed by the National Institute of Radiological Sciences (NIRS) during the period between 27 June and 28 July 2011. The 174 subjects consisted of 125 adults (≥18-y) and 49 children (<18-y) and included 90 persons of Namie town, one of the municipalities heavily contaminated with the radionuclides. The number of subjects with significant detection of both Cs and Cs was relatively small: 28.8% for the adults and 4.1% for the children. A significant gender difference in the Cs detection rate (males > females) was observed in the adults but not the children. In this study, the committed effective dose (CED) from Cs and Cs was calculated based on individual WB contents (Cs) corrected against body size, the observed body content ratio of Cs to Cs, and the assumed intake scenario (namely, acute inhalation of Type F compounds on 12 March 2011 when the first explosive event occurred at the site of the FDNPP). The 90th-percentile CED value for the adults was around 0.1 mSv and the maximum CED (0.63 mSv) was found in an elderly male. Comparable CED results were obtained in other WB measurements subsequently performed by the Japan Atomic Energy Agency (JAEA) in a similar manner to that of the NIRS, suggesting that the contribution of ingestion to the WB content observed would be trivial for most of the JAEA subjects. The intake ratio of I to Cs was evaluated to be 3~5 based on the I thyroid measurement data of Tokonami et al. Using the average intake ratio of 3.8, the resulting median and maximum thyroid-equivalent doses to the adult subjects of this study were estimated at 3.5 mSv and 84 mSv, respectively.

[Effects on health of the Chernobyl accident: 30 years on]

This paper reflects the current state of research into the short- and long-term effects on health in the former Soviet Union and Europe of the nuclear accident in Chernobyl. It discusses the latest results of epidemiological studies and presents future research perspectives.

Pooled Bayesian meta-analysis of two Polish studies on radiation-induced cancers

The robust Bayesian regression method was applied to perform meta-analysis of two independent studies on influence of low ionising radiation doses on the occurrence of fatal cancers. The re-analysed data come from occupational exposure analysis of nuclear workers in Świerk (Poland) and from ecological study of cancer risk from natural background radiation in Poland. Such two different types of data were analysed, and three popular models were tested: constant, linear and quadratic dose-response dependencies. The Bayesian model selection algorithm was used for all models. The Bayesian statistics clearly indicates that the popular linear no-threshold (LNT) assumption is not valid for presented cancer risks in the range of low doses of ionising radiation. The subject of LNT hypothesis use in radiation risk prediction and assessment is also discussed.

Risk perception, trust, and factors related to a planned new nuclear power plant in Taiwan after the 2011 Fukushima disaster

After the Fukushima nuclear disaster in March 2011, an international review of nuclear safety indicated that two of the three nuclear power plants (NPPs) operating in Taiwan were listed as the most dangerous in the world. To understand the perception of NPP risks by the public in Taiwan and their attitudes regarding a planned fourth NPP after the Fukushima nuclear incident in 2011, a study was conducted in August 2011. A sample of 2819 individuals responded to the survey, with 66% perceiving that Taiwan's safety management of NPPs was inferior to Japan's, while 40% perceived a higher possibility of nuclear accidents like that in Japan. On average, a 'safe' distance of 94 km from an NPP was expected. 56% opposed the planned fourth NPP, with females (adjusted odd ratios (aOR) 2.03; 95% confidence interval (CI) 1.71-2.41), residence near the planned fourth NPP (aOR/CI 13.90/7.79-24.80), distrust of safety management (aOR/CI 1.98/1.45-2.69) and emergency planning (aOR/CI 1.89/1.49-2.40) as the main determinants. Others included those who expected larger safe distances from an NPP (trend test, p < 0.001), perceived excess cancer risks of living within 30 km of an NPP (aOR/CI 2.74/2.02-3.71), and projection of no electric shortage without NPPs (aOR/CI 1.93/1.50-2.49). Given that Taiwan's large population lives close to the existing NPPs and long-term concerns about the safety of these nuclear plants, the Fukushima incident in Japan likely augmented public risk perceptions on nuclear power in general and on the planned fourth NPP.

Predicting the environmental risks of radioactive discharges from Belgian nuclear power plants

An environmental risk assessment (ERA) was performed to evaluate the impact on non-human biota from liquid and atmospheric radioactive discharges by the Belgian Nuclear Power Plants (NPP) of Doel and Tihange. For both sites, characterisation of the source term and wildlife population around the NPPs was provided, whereupon the selection of reference organisms and the general approach taken for the environmental risk assessment was established. A deterministic risk assessment for aquatic and terrestrial ecosystems was performed using the ERICA assessment tool and applying the ERICA screening value of 10 μGy h(-1). The study was performed for the radioactive discharge limits and for the actual releases (maxima and averages over the period 1999-2008 or 2000-2009). It is concluded that the current discharge limits for the Belgian NPPs considered do not result in significant risks to the aquatic and terrestrial environment and that the actual discharges, which are a fraction of the release limits, are unlikely to harm the environment.

Chromosome analysis of nuclear power plant workers using fluorescence in situ hybridization and Giemsa assay

The aim of this study was to evaluate the genotoxic effects of ionizing radiation in vivo in exposed Bulgarian nuclear power plant workers by using classical cytogenetic and molecular cytogenetic analyses of peripheral lymphocytes. Chromosome analysis using fluorescence in situ hybrydization (FISH) and Giemsa techniques was undertaken on 63 workers and 45 administrative staff controls from the Bulgarian Nuclear Power Plant. Using the Giemsa method, the frequencies of cells studied with chromosome aberrations, dicentrics plus rings and chromosome fragments in the radiation workers were significantly higher compared with the control group (P = 0.044, P = 0.014, and P = 0.033, respectively). A significant association between frequencies of dicentrics plus rings and accumulated doses was registered (P < 0.01). In the present study, a FISH cocktail of whole chromosome paints for chromosomes 1, 4 and 11 was used. A significant association between frequency of translocations and accumulated doses was also observed (P < 0.001). Within the control group, a correlation was found between age and the spontaneous frequency of translocations. No correlation was found between smoking status and frequency of translocations. When compared with the control group, workers with accumulated doses up to 100 mSv showed no increase in genome translocation frequency, whereas workers with accumulated doses from 101 to 200 mSv showed a statistically significant doubling of genome translocation frequency (P = 0.009). Thus, in cases of chronic exposure and for purposes of retrospective dosimetry, the genome frequency of translocations is a more useful marker for evaluation of genotoxic effects than dicentric frequency.

Chernobyl cleanup workers from Estonia: follow-up for cancer incidence and mortality

This study examined cancer incidence (1986-2008) and mortality (1986-2011) among the Estonian Chernobyl cleanup workers in comparison with the Estonian male population. The cohort of 4810 men was followed through nationwide population, mortality and cancer registries. Cancer and death risks were measured by standardised incidence ratio (SIR) and standardised mortality ratio (SMR), respectively. Poisson regression was used to analyse the effects of year of arrival, duration of stay and time since return on cancer and death risks. The SIR for all cancers was 1.06 with 95% confidence interval 0.93-1.20 (232 cases). Elevated risks were found for cancers of the pharynx, the oesophagus and the joint category of alcohol-related sites. No clear evidence of an increased risk of thyroid cancer, leukaemia or radiation-related cancer sites combined was apparent. The SMR for all causes of death was 1.02 with 95% confidence interval 0.96-1.08 (1018 deaths). Excess mortality was observed for mouth and pharynx cancer, alcohol-related cancer sites together and suicide. Duration of stay rather than year of arrival was associated with increased mortality. Twenty-six years of follow-up of this cohort indicates no definite health effects attributable to radiation, but the elevated suicide risk has persisted.

Assessing the possible radiological impact of routine radiological discharges from proposed nuclear power stations in England and Wales

The aim of this work is to assess the possible radiological impact on the population of the United Kingdom (UK) from new nuclear power stations proposed for up to eight sites in England and Wales. The radiological impact was measured in terms of collective dose to the UK, European and world populations from a single year's discharge integrated to 500 and 100 000 years and the annual dose to an average member of the UK population (known as the per-caput dose). The doses were calculated for two reactor types, UK EPR™ and AP1000™, using the annual expected discharges estimated by the designers of the reactors and assuming two reactors per site. In addition, typical individual doses to adults living close to the sites were calculated on the basis of continuous discharges for 60 years (the assumed lifetime of the reactors). The dose to a representative person (previously known as the critical group) was not calculated, as this has been done elsewhere. The assessments were carried out using the software program PC-CREAM 08(®) which implements the updated European Commission methodology for assessing the radiological impact of routine releases of radionuclides to the environment. The collective dose truncated to 500 years to the UK population was estimated to be 0.5 manSv assuming UK EPR reactors on all sites and 0.6 manSv assuming AP1000s on three sites with UK EPRs on the other sites. The most significant contribution to the collective dose to the UK population is due to the global circulation of carbon-14 released to the atmosphere. The annual dose to an average member of the UK population from all sites was calculated to be around 10 nSv y(-1) and would therefore contribute little to an individual's total radiation dose. All the calculated doses to a typical adult living near the sites assuming continuous discharges for 60 years were found to be below 1 μSv y(-1).

[Risk communication in construction of new nuclear power plant]

Accompanied by construction of new nuclear power plants in the coming decades in China, risk management has become increasingly politicized and contentious. Nuclear risk communication is a critical component in helping individuals prepare for, respond to, and recover from nuclear power emergencies. It was discussed that awareness of trust and public attitudes are important determinants in nuclear power risk communication and management. However, there is limited knowledge about how to best communicate with at-risk populations around nuclear power plant in China. To bridge this gap, this study presented the attitudinal data from a field survey in under-building Haiyang nuclear power plant, Shandong Province to measure public support for and opposition to the local construction of nuclear power plant. The paper discussed the structure of the communication process from a descriptive point of view, recognizing the importance of trust and understanding the information openness. The results showed that decision-making on nuclear power was dominated by a closed "iron nuclear triangle" of national governmental agencies, state-owned nuclear enterprises and scientific experts. Public participation and public access to information on nuclear constructions and assessments have been marginal and media was a key information source. As information on nuclear power and related risks is very restricted in China, Chinese citizens (51%) tend to choose the government as the most trustworthy source. More respondents took the negative attitudes toward nuclear power plant construction around home. It drew on studies about risk communication to develop some guidelines for successful risk communication. The conclusions have vast implications for how we approach risk management in the future. The findings should be of interest to state and local emergency managers, community-based organizations, public health researchers, and policy makers.

Estimation of the total population moving into and out of the 20 km evacuation zone during the Fukushima NPP accident as calculated using "Auto-GPS" mobile phone data

The first objective data showing the geographical locations of people in Fukushima after the Fukushima Dai-ichi nuclear power plant accident, obtained by an analysis of GPS (Global Positioning System)-enabled mobile phone logs, are presented. The method of estimation is explained, and the flow of people into and out of the 20 km evacuation zone during the accident is visualized.

An analysis of the radiation field characteristics for extremity dose assessment during maintenance periods at nuclear power plants in Korea

Workers who maintain the water chambers of steam generators during maintenance periods in nuclear power plants (NPPs) have a higher likelihood of high radiation exposure, even if they are exposed for a short period of time. In particular, it is expected that the hands of workers would receive the highest radiation exposure as a consequence of hand contact with radioactive materials. In this study, a characteristic analysis of inhomogeneous radiation fields for contact operations was conducted using thermoluminescent dosemeters for the whole body and extremities during maintenance periods at Korean NPPs. It was observed that inhomogeneous radiation fields for contact operations at NPPs were dominated by high-energy photons.

How much is too little to detect impacts? A case study of a nuclear power plant

Several approaches have been proposed to assess impacts on natural assemblages. Ideally, the potentially impacted site and multiple reference sites are sampled through time, before and after the impact. Often, however, the lack of information regarding the potential overall impact, the lack of knowledge about the environment in many regions worldwide, budgets constraints and the increasing dimensions of human activities compromise the reliability of the impact assessment. We evaluated the impact, if any, and its extent of a nuclear power plant effluent on sessile epibiota assemblages using a suitable and feasible sampling design with no ‘before’ data and budget and logistic constraints. Assemblages were sampled at multiple times and at increasing distances from the point of the discharge of the effluent. There was a clear and localized effect of the power plant effluent (up to 100 m from the point of the discharge). However, depending on the time of the year, the impact reaches up to 600 m. We found a significantly lower richness of taxa in the Effluent site when compared to other sites. Furthermore, at all times, the variability of assemblages near the discharge was also smaller than in other sites. Although the sampling design used here (in particular the number of replicates) did not allow an unambiguously evaluation of the full extent of the impact in relation to its intensity and temporal variability, the multiple temporal and spatial scales used allowed the detection of some differences in the intensity of the impact, depending on the time of sampling. Our findings greatly contribute to increase the knowledge on the effects of multiple stressors caused by the effluent of a power plant and also have important implications for management strategies and conservation ecology, in general.

Tritium release during nuclear power operation in China

Overviews were evaluated of tritium releases and related doses to the public from airborne and liquid effluents from nuclear power plants on the mainland of China before 2009. The differences between tritium releases from various nuclear power plants were also evaluated. The tritium releases are mainly from liquid pathways for pressurised water reactors, but tritium releases between airborne and liquid effluents are comparable for heavy water reactors. The airborne release from a heavy water reactor is obviously higher than that from a pressurised water reactor.

The Chernobyl experience in the area of retrospective dosimetry

The Chernobyl accident, which occurred on 26 April 1986 at a nuclear power plant located less than 150 km north of Kiev, was the largest nuclear accident to date. The unprecedented scale of the accident was determined not only by the amount of released activity, but also by the number of workers and of the general public involved, and therefore exposed to increased doses of ionising radiation. Due to the unexpected and large scale of the accident, dosimetry techniques and practices were far from the optimum; personal dosimetry of cleanup workers (liquidators) was not complete, and there were no direct measurements of the exposures of members of the public. As a result, an acute need for retrospective dose assessment was dictated by radiation protection and research considerations. In response, substantial efforts have been made to reconstruct doses for the main exposed cohorts, using a broad variety of newly developed methods: analytical, biological and physical (electron paramagnetic resonance spectroscopy of teeth, thermoluminescence of quartz) and modelling. This paper reviews the extensive experience gained by the National Research Center for Radiation Medicine, Academy of Medical Sciences, Ukraine in the field of retrospective dosimetry of large cohorts of exposed population and professionals. These dose reconstruction projects were implemented, in particular, in the framework of epidemiological studies, designed to follow-up the medical consequences of the Chernobyl accident and study health effects of ionizing radiation, particularly Ukrainian-American studies of cataracts and leukaemia among liquidators.

Mental health consequences of the Chernobyl disaster

The psychosocial consequences of disasters have been studied for more than 100 years. The most common mental health consequences are depression, anxiety, post-traumatic stress disorder, medically unexplained somatic symptoms, and stigma. The excess morbidity rate of psychiatric disorders in the first year after a disaster is in the order of 20%. Disasters involving radiation are particularly pernicious because the exposure is invisible and universally dreaded, and can pose a long-term threat to health. After the Chernobyl disaster, studies of clean-up workers (liquidators) and adults from contaminated areas found a two-fold increase in post-traumatic stress and other mood and anxiety disorders and significantly poorer subjective ratings of health. Among liquidators, the most important risk factor was severity of exposure. In general population samples, the major risk factor was perceived exposure to harmful levels of radiation. These findings are consistent with results from A-bomb survivors and populations studied after the Three Mile Island nuclear power plant accident. With regard to children, apart from findings from ecological studies that lack direct data on radiation or other teratologic exposures and local studies in Kiev, the epidemiologic evidence suggests that neither radiation exposure nor the stress of growing up in the shadow of the accident was associated with emotional disorders, cognitive dysfunction, or impaired academic performance. Thus, based on the studies of adults, the Chernobyl Forum concluded that mental health was the largest public health problem unleashed by the accident. Since mental health is a leading cause of disability, physical morbidity, and mortality, health monitoring after radiation accidents like Fukushima should include standard measures of well-being. Moreover, given the comorbidity of mental and physical health, the findings support the value of training non-psychiatrist physicians in recognizing and treating common mental health problems like depression in Fukushima patients.

Epidemiological studies of Fukushima residents exposed to ionising radiation from the Fukushima Daiichi Nuclear Power Plant prefecture--a preliminary review of current plans

It is now more than six months since the beginning of the accident on 11 March 2011 at the Fukushima Daiichi Nuclear Power Plant in Japan. The Japanese government and local health authorities have started to collect the information necessary to estimate radiation doses received by those living in the area around the plant, drafted plans for the health care of residents, and started to implement some of them. This paper reviews and discusses the studies necessary for risk evaluation of cancer and non-cancer diseases, including those already planned, mainly from the view point of evaluating health risk using epidemiological approaches. In the long run, it is important to establish a cohort with a control group. Even if the cumulative doses are estimated to be so low that it is difficult to evaluate the risk of cancer and non-cancer diseases, it is necessary to conduct such a study to reassure residents. The health care programme of the Fukushima Prefecture government, including health check-ups of residents, will help to assess indirect effects of radiation exposure, including psychological problems. The success of any studies of radiation epidemiology depends on the collection of accurate information on radiation doses received by the study subjects. However, some of the dosimetry surveys were not conducted in a timely manner. (It should be recognised, though, that such a problem might have been inevitable, considering the chaotic condition after the nuclear accident.) Accurate estimation of the radiation dose received by each resident is not only important for scientific risk evaluation but also to inform each resident about his or her potential risk. Otherwise, residents will bear an undue psychological burden from uncertainties regarding their radiation exposure and its health consequences. One of other important tasks in Fukushima is the improvement of the quality of the regional cancer registry in this prefecture. It is also important to start thyroid cancer screening in a year or two since the expected minimum latent period among those exposed in early childhood is about 4 years. Recently, local health authorities decided to start a thyroid screening programme for those aged 18 years or younger. Any scientific efforts in Fukushima, which need to gain the trust of study subjects about the objectivity of research, may suffer from the fact that residents in Fukushima Prefecture have begun to suspect that the Japanese government and local authorities are keeping important information from them. It seems necessary to make more effort to reflect the opinions of residents when planning health care programmes and to gain the understanding of the public for the programme. In summary, there are many problems that make the evaluation of cancer and non-cancer disease risk in Fukushima difficult. The help of international colleagues will be invaluable for overcoming those problems. In this paper, these efforts are briefly summarised and some comments are made.

Lessons from Chernobyl and prognosis for Fukushima: radiological consequences

The following are considered: results of large-scale radiation epidemiological studies of the health effects of the Chernobyl accident, radiation risks for emergency workers and the affected population; and verification of ICRP risk models taking into account data on the Chernobyl accident and preliminary prognostic estimates of potential radiological consequences of the Fukushima disaster.

Preparing a scientific report to the general assembly on 'exposures due to the nuclear accident following the Great East-Japan earthquake and tsunami'

At its 58th session in May 2011, the United Nations Committee on the Effects of Atomic Radiation (UNSCEAR) decided to carry out, once sufficient information was available, a full assessment of the levels of exposure and radiation risks attributable to the Fukushima accident. It envisages a preliminary document for consideration at its 59th session in May of 2012 and a more complete report for the 60th session of the Committee in 2013. This paper summarises the aims and objectives of the project, the scope, the working arrangements as well as the relation of the work to other activities.

Some lessons on radiological protection learnt from the accident at the Fukushima Dai-ichi nuclear power plant

The accident at the Fukushima Dai-ichi nuclear power plant released a large quantity of radioactive iodine and caesium into the environment. In terms of radiological protection, the evacuation and food restrictions that were adopted in a timely manner by the authorities effectively reduced the dose received by people living in the affected area. Since late March, the transition from an emergency to an existing exposure situation has been in progress. In selecting the reference exposure levels in some areas under an existing exposure situation, the authorities tried to follow the situation-based approach recommended by the ICRP. However, a mixture of emergency and post-emergency approaches confused the people living in the contaminated areas because the reactor conditions continued to be not completely stable. In deriving the criteria in an existing exposure situation, the regulatory authority selected 20 mSv y(-1). The mothers in the affected area believed that a dose of 20 mSv y(-1) was unacceptably high for children since 1 mSv y(-1) is the dose limit for the public under normal conditions. Internet information accelerated concern about the internal exposure to children and the related health effects. From some experiences after the accident the following lessons could be learned. The selection of reference doses in existing exposure situations after an accident must be openly communicated with the public using a risk-informed approach. The detriment-adjusted nominal risk coefficient was misused for calculating the hypothetical number of cancer deaths by some non-radiation experts. It would not be possible to resolve this problem unless the ICRP addressed an alternative risk assessment to convey the meaning and associated uncertainty of the risk to an exposed population. A situation-based approach in addition to a risk-informed approach needs to be disseminated properly in order to select the level of protection that would be the best possible under the prevailing circumstances. A dialogue between radiation and other risk experts such as those dealing with chemical exposures is now needed.

Thyroid cancer in Ukraine after the Chernobyl accident (in the framework of the Ukraine-US Thyroid Project)

As a result of the accident at the Chernobyl Nuclear Power Plant, millions of residents of Belarus, Russia, and Ukraine were exposed to large doses of radioactive iodine isotopes, mainly I-131. The purpose of the Ukraine-American (UkrAm) and Belarus-American (BelAm) projects are to quantify the risks of thyroid cancer in the framework of a classical cohort study, comprising subjects who were aged under 18 years at the time of the accident, had direct measurements of thyroid I-131 radioactivity taken within two months after the accident, and were residents of three heavily contaminated northern regions of Ukraine (Zhitomir, Kiev, and Chernigov regions). Four two-year screening examination cycles were implemented from 1998 until 2007 to study the risks associated with thyroid cancer due to the iodine exposure caused during the Chernobyl accident. A standardised procedure of clinical examinations included: thyroid palpation, ultrasound examination, blood collection followed by a determination of thyroid hormone levels, urinary iodine content test, and fine-needle aspiration if required. Among the 110 cases of thyroid cancer diagnosed in UkrAm as the result of four screening examinations, 104 cases (94.5%) of papillary carcinomas, five cases (4.6%) of follicular carcinomas, and one case (0.9%) of medullary carcinoma were diagnosed.

Estimated lag time in global carbon emissions and CO2 concentrations produced by commercial nuclear power through 2009 with projections through 2030

This study examines the past and future impact of nuclear reactors on anthropogenic carbon emissions to the atmosphere. If nuclear power had never been commercially developed, what additional global carbon emissions would have occurred? More than 44 y of global nuclear power have caused a lag time of at least 1.2 y in carbon emissions and CO2 concentrations through the end of 2009. This lag time incorporates the contribution of life cycle carbon emissions due to the construction and operation of nuclear plants. Cumulative global carbon emissions would have been about 13 Gt greater through 2009, and the mean annual CO2 concentration at Mauna Loa would have been ~2.7 ppm greater than without nuclear power. This study finds that an additional 14–17 Gt of atmospheric carbon emissions could be averted by the global use of nuclear power through 2030, for a cumulative total of 27–30 Gt averted during the period 1965–2030. This result is based on International Atomic Energy Agency projections of future growth in nuclear power from 2009–2030, modified by the recent loss or permanent shutdown of 14 reactors in Japan and Germany

The third analysis of cancer mortality among Japanese nuclear workers, 1991-2002: estimation of excess relative risk per radiation dose

The present study estimated excess relative risk per sievert (ERR/Sv) of cancer mortality among the cohort of 200 583 male Japanese nuclear workers, with an average individual cumulative dose of 12.2 mSv (<10 mSv, 75.4%; 100 + mSv, 2.6%), conducting Poisson regression using dose category specific observed and expected numbers of deaths, and average doses obtained from the official report of the Radiation Effects Association (REA) on the analysis of mortality of Japanese nuclear industry workers for 1991-2002, which reported the estimates of ERR/Sv for leukaemia but not for all cancers or any other cancer site. The possible confounding biases from drinking alcohol and smoking tobacco were evaluated by examining the association of cumulative radiation dose with the mortality of cancers related to drinking or smoking. For leukaemia (80 deaths), the estimate of ERR/Sv was - 1.93 (95% confidence interval (CI) = - 6.12, 8.57). For all cancers excluding leukaemia (2636 deaths), while the ERR/Sv was estimated to be 1.26 (95%CI = - 0.27, 3.00), confounding by alcohol consumption was suspected since the ERR/Sv estimate of alcohol-related cancers was 4.64 (95%CI = 1.13, 8.91) and the ERR/Sv estimate of all cancers excluding leukaemia and alcohol-related cancers was 0.20 (95%CI = - 1.42, 2.09). In conclusion, confounding by important lifestyle factors related to cancer risk may have a substantial effect on risk estimates, especially when conducting studies of low cumulative dose and, accordingly, low statistical power. Pooled analysis or meta-analysis of nuclear workers for solid cancers needs to take this point into account.

Radiation epidemiology: a perspective on Fukushima

For nearly 100 years, epidemiologic studies of human populations exposed to ionising radiation have provided quantitative information on health risks. High dose deterministic (tissue reaction) effects result when sufficient numbers of functioning cells are killed, such as in bone marrow depression that can lead to death. Lower dose stochastic effects are probabilistic in nature and include an increased risk of cancer later in life and heritable genetic defects, although genetic conditions in the children of irradiated parents have yet to be convincingly demonstrated. Radiation studies are of diverse populations and include not only the Japanese atomic bomb survivors, but also patients treated with radiation for malignant and non-malignant disease; patients exposed for diagnostic purposes; persons with intakes of radionuclides; workers occupationally exposed; and communities exposed to environmental and accidentally released sources of radiation. Much is known about radiation and its risks. The major unanswered question in radiation epidemiology, however, is not whether radiation causes cancer, but what the level of risk is following low dose (<100 mSv) or low dose rate exposures. Paracelsus is credited with first articulating that the 'poison is in the dose', which for radiation epidemiology translates as 'the lower the dose, the lower the risk' and, an important corollary, the lower the dose, the greater the difficulty in detecting any increase in the number of cancers possibly attributable to radiation. In contrast to the Chernobyl reactor accident, the Fukushima reactor accident has to date resulted in no deterministic effects and no worker deaths. Estimates to date of population doses suggest very low uptakes of radioactive iodine which was a major determinant of the epidemic of thyroid cancer following childhood exposures around Chernobyl. The estimates to date of population doses are also much lower (and the distribution much narrower) than the doses for which cancer excesses have been detected among atomic bomb survivors after 60 years of follow-up. Studies of populations exposed to low doses are also limited in their ability to account for important lifestyle factors, such as cigarette smoking and medical x-ray exposures, which could distort findings. Studies of the Fukushima population should be and are being considered for reassurance and health care reasons. Apart from as regards the extreme psychological stress caused by the horrific loss of life following the tsunami and the large-scale evacuation from homes and villages, such studies have limited to no chance of providing information on possible health risks following low dose exposures received gradually over time--the estimated doses (to date) are just too small.

Evidence of confounding by smoking of associations between radiation and lung cancer mortality among workers at the Savannah River Site

BACKGROUND

This study investigates confounding by cigarette smoking of associations between occupational exposure to ionizing radiation and lung cancer mortality among workers at the Savannah River Site (SRS).

METHODS

Thirteen thousand two hundred sixty-five white males hired at SRS between 1950 and 1986 were followed through 2002 to ascertain causes of death. Estimates of radiation doses from external sources and internal tritium uptakes were derived from dosimetry records. Logistic regression methods were used to derive discrete-time estimates of rate ratios. An indirect approach to control for unmeasured confounding by smoking was employed that involves joint modeling of lung cancer and chronic obstructive pulmonary disease (COPD) mortality.

RESULTS

Prior to indirect adjustment for smoking, there was minimal evidence of association between lung cancer mortality and cumulative radiation dose under a 10-year lag assumption (RR at 100 mSv = 0.90; 90% CI: 0.80-1.01). Subsequent to indirect adjustment for smoking, the association between lung cancer mortality and cumulative radiation dose under a 10-year lag was positive (RR at 100 mSv = 1.33; 90% CI: 1.01-1.77).

CONCLUSIONS

In this cohort, there is evidence of negative confounding of radiation dose–lung cancer mortality associations by cigarette smoking.

Cancer risks near nuclear facilities: the importance of research design and explicit study hypotheses

BACKGROUND

In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design.

OBJECTIVES

We review epidemiologic principles used in studies of generic exposure-response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities.

DISCUSSION

Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders.

CONCLUSIONS

Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes.

Radiation protection at U.S. nuclear power plants--today and tomorrow

The nuclear power industry work ethic and culture is founded on learning from experience and continuously finding ways to improve performance--especially in regard to radiation safety. Over the past 25 y, this process of continuous improvement has yielded exceptional results in regard to radiation protection of workers, the public and the environment. In light of the resurgence of nuclear energy in the United States, the nuclear power industry is developing strategies to achieve continuous improvements to performance and address emerging challenges in the area of radiation protection.

Panel session on "safety, health and the environment: implications of nuclear power growth"

This paper summarizes the presentations and the insights offered by panelists John P. Winston, Robert Bernero, and Stephen LaMontagne during the Panel on Safety, Health and the Environment: Implications of Nuclear Power Growth that took place during the NCRP 2009 Annual Meeting. The paper describes the opportunities and the challenges faced in the areas of infrastructure development, radiation control, licensing and regulatory issues, and non-proliferation as a consequence of the forecasted growth in nuclear power capacity worldwide.

Panel session on international perspectives on the future of nuclear power

The 2009 National Council on Radiation Protection (NCRP) Annual Meeting provided an opportunity to exchange viewpoints and consider current information regarding the evolution of selected commercial nuclear power trends worldwide. Within the overall topical context of radiation-related regulation, focus was placed on activities in the United Kingdom, Japan, and the United States, although general global developments were reviewed to some extent. This paper provides the reader with a sense of these activities as described by the authors and presenters: David Bennett (Environmental Agency, United Kingdom), Alan Hanson (AREVA), Shojiro Matsuura (Japan Nuclear Safety Research Association), and Alexander Marion (Nuclear Energy Institute).

Dutch distribution zones of stable iodine tablets based on atmospheric dispersion modelling of accidental releases from nuclear power plants

Rapid administration of stable iodine is essential for the saturation and subsequent protection of the thyroid gland against the potential harm caused by radioiodines. This paper proposes the Dutch risk analysis that uses an atmospheric dispersion model to calculate the size of the zones around nuclear power plants where radiological thyroid doses for children might be sufficiently high to warrant iodine administration. Dose calculations for possible releases from the nuclear power plants of Borssele (The Netherlands), Doel (Belgium) and Emsland (Germany) are based on two scenarios in combination with a 1-y set of authentic, high-resolution meteorological data. The dimensions of the circular zones were defined for each nuclear power plant. In these zones, with a radius up to 50 km, distribution of stable iodine tablets is advised.

Mortality patterns among Paducah Gaseous Diffusion Plant workers

OBJECTIVE

To determine whether Paducah Gaseous Diffusion Plant workers had mortality patterns that differed from the general US population and to investigate whether mortality patterns were associated with job title or workplace exposures.

METHODS

A retrospective occupational cohort mortality study was conducted on 6759 workers. Standardized mortality ratio analyses compared the cohort with the referent US population. Internal comparisons producing standardized rate ratios were conducted by job title, metal exposure, and cumulative internal and external radiation exposures.

RESULTS

Overall mortality and cancer rates were lower than the referent population, reflecting a strong healthy worker effect. Individual not significant standardized mortality ratios and standardized rate ratios were noted for cancers of the lymphatic and hematopoietic tissue.

CONCLUSIONS

Although relatively low exposures to radiation and metals did not produce statistically significant health effects, no significant elevations for lymphatic and hematopoietic cancers were consistent with previous studies of nuclear workers.

Incomplete data on the Canadian cohort may have affected the results of the study by the International Agency for Research on Cancer on the radiogenic cancer risk among nuclear industry workers in 15 countries

In 1995 the International Agency for Research on Cancer (IARC) completed a study that involved nuclear workers from facilities in the USA, UK and Canada. The only significant, though weak, dose-related associations found were for leukaemia and multiple myeloma. The results for the Canadian cohort, which comprised workers from the facilities of Atomic Energy of Canada Limited (AECL), were compatible with those for the other national cohorts. In 2005, IARC completed a further study, involving nuclear workers from 15 countries, including Canada. In these results, the dose-related risk for leukaemia was not significant but the prominent finding was a statistically significant excess relative risk per sievert (ERR Sv(-1)) for 'all cancers excluding leukaemia'. Surprisingly, the risk ascribed to the Canadian cohort for all cancers excluding leukaemia, driven by the AECL sub-cohort, was significantly higher than the risk estimate for the 15-country cohort as a whole. We have attempted to identify why the results for the AECL cohort were so discrepant and had such a remarkable influence on the 15-country risk estimate. When considering the issues associated with data on the AECL cohorts and their handling, we noted a striking feature: a major change in outcome of studies that involved Canadian nuclear workers occurred concomitantly with the shift to when data from the National Dose Registry (NDR) of Canada were used directly rather than data from records at AECL. We concluded that an important contributor to the considerable upward shift in apparent risk in the 15-country and other Canadian studies that have been based on the NDR probably relates to pre-1971 data and, in particular, the absence from the NDR of the person-years of workers who had zero doses in the calendar years 1956 to 1970. Our recommendation was for there to be a comprehensive evaluation of the risks from radiation in nuclear industry workers in Canada, organisation by organisation, in which some of the anomalies that we have identified might be addressed.

Development of tritiated vapor absorbent applicable to the atmospheric detritiation system in a nuclear facility

The combination of hydrogen oxidation reactor packed noble metal catalysts and water vapor absorber has been applied to the atmospheric detritiation system of the tritium handling facility. Commercial synthetic zeolite such as molecular sieve 5A has been used as an adsorbent of ADS absorber. In the case of application of molecular sieve 5A to the ADS absorber of a large-scale tritium handling facility such as a future fusion plant, an absorber becomes huge due mainly to the difficulty in dehydration from molecular sieve 5A. Hence, application of CaY Faujasite-type zeolite with a high framework silica-to-alumina ratio to the adsorbent for atmospheric detritiation system was investigated. It was clear that the dehydration behavior at room temperature was significantly improved using CaY zeolite. In contrast, detritiation factor for CaY zeolite with a high framework silica-to-alumina ratio depended strongly on the space velocity through the absorber. To apply CaY zeolite with a high framework SiO(2)/Al(2)O(3) ratio to the ADS absorbent, the space velocity less than 250h(-1) was recommended to maintain the detritiation factor more than 1000. The steep increase in water adsorption at the relative pressure lower than 0.05 is a feature of synthetic zeolite with calcium cation. However, such an increase was not observed in water adsorption on CaY zeolite with a framework SiO(2)/Al(2)O(3) ratio more than 7.0. Consequently, the CaY zeolite with the framework SiO(2)/Al(2)O(3) ratio of 5.0 is a promising candidate as absorbent of ADS absorber.