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The article presents abstracts on topics related to radiological protection which include the issues during and after the Fukushima nuclear reactor accident in Japan, the estimation of health risks from ionising radiation exposure and the risk associated with low dose radiation exposure.

The full text of the Editorial is given in the PDF file. [ABSTRACT FROM AUTHOR]

This paper presents an overview of current internal dose estimates from the Fukushima accident, potential population specific uncertainties in these estimates are investigated, along with the relative effects of internal and external exposures. Thyroid doses were largely due to 131I, but variations in thyroid weight and fractional uptake and retention times of 131I in the thyroid contribute to uncertainties in thyroid dose estimates. Lower values for these parameters in the Japanese population, as compared to international reference assumptions, would lead to underestimation of doses on the basis of reference thyroid weights and overestimation of doses using reference thyroid uptake and retention times. Any overall bias in thyroidal doses due to population specific factors is the net result of the balance between these effects. Internal doses to other organs are largely due to 134Cs and 137Cs and their whole body distribution, population specific differences in these dose estimates are driven by average body mass, due to the inverse relationship between this and retention times. Potential differences in dose estimates and any inferred risks, due to local population specific factors, may be less than a factor of two for children and male adults, but the potential difference may be slightly underestimated for female adults. Recent micro-dosimetric studies have confirmed the existing perception that risk from internal exposures to 137Cs, 134Cs, and 131I should be nearly equivalent to that from external exposure to gamma rays at the same absorbed dose. Epidemiological studies provide comparisons between external and internal exposures to 131I in children and suggest that effects of internal exposure are similar to those of external exposure. Effective dose has been formulated to harmonise internal and external exposure risks for radiation protection purposes. On the basis of this review, the use of effective dose in this context does not seem to be unreasonable. [ABSTRACT FROM AUTHOR]

The European ALARA Network regularly organises workshops on topical issues in radiation protection. In light of the Fukushima accident, the most recent workshop questioned the application of the ALARA principle in emergency exposure situations. This memorandum presents the conclusions and recommendations of this workshop. One of the outcomes is that the process of optimisation in emergency exposure situations should be flexible enough to be able to modify or refine decisions over the course of an accident. In the urgent phase, decisions must be made in a very time-constrained environment, based on scarce, uncertain and sometimes unreliable information. In this phase, optimisation and protection strategies are therefore developed and applied on the basis of conservative assumptions or ‘reasonably foreseeable worst-case scenario’ which could lead to an overestimation of the consequences. In the intermediate phase, knowledge of the situation improves, and more time is available to make the decision. This is reflected by adopting a less conservative approach, and transitioning to a more appropriate optimisation adapted as effectively as possible to the various exposure situations. When the situation is eventually stabilized (transition phase), there is time to shape the measures taken previously to reflect local conditions in the affected territories. In every phase, consideration should be given to the stakeholders, so that their needs and requirements can be incorporated as effectively as possible. [ABSTRACT FROM AUTHOR]

In the first paper of this series, we showed that the ratio c of individual dose to ambient dose did not change with time in Date City, Fukushima Prefecture, after the Fukushima Daiichi Nuclear Power Plant accident. The purpose of the present paper, the second in a series, is to estimate the lifetime doses of the Date City residents, based on continuous glass badge monitoring data, extrapolated by means of the ambient-dose-rate reduction function obtained from the airborne monitoring data. As a result, we found that the external exposure contribution to the mean additional lifetime dose of residents living in Date City is not expected to exceed 18 mSv. In addition, effects of decontamination on the reduction of individual doses were not evident. This method of combining individual doses and the ambient doses, as developed in this study, has made it possible to predict with reasonable certainty the lifetime doses of residents who continue to live in this radiologically contaminated area. [ABSTRACT FROM AUTHOR]

The Fukushima Daichi Nuclear Power Plant disaster, which began on 11 March 2011, provided a crucial opportunity to evaluate the state of preparation on the part the powerplant operator (TEPCO), relevant Japanese government agencies, and international oversight bodies, to gather necessary information on radiation risks quickly and to share it with those tasked with emergency response as well as with the general public. The inadequacy of this preparation and the chaotic nature of inter-agency and inter-governmental communication has been well noted in several official reports on the disaster. In response, Safecast, an international, volunteer-based organization devoted to monitoring and openly sharing information on environmental radiation and other pollutants, was initiated on 12 March 2011, one day following the start of the accident. Since then the group has implemented participatory, open-source, citizen-science-centered radiation mapping solutions developed through a process of collaborative open innovation. The information Safecast provided has proven useful to experts, to policy makers, and to the public. This paper briefly describes the methodology and toolsets Safecast has developed and deployed, as well as organizational and social aspects, and summarizes key results obtained to date. In addition, it discusses appropriate criteria for evaluating the success of citizen-science efforts like Safecast, and places it in context with other non-governmental radiation monitoring efforts. [ABSTRACT FROM AUTHOR]

MELODI is the European platform dedicated to low-dose radiation risk research. From 7 October through 10 October 2013 the Fifth MELODI Workshop took place in Brussels, Belgium. The workshop offered the opportunity to 221 unique participants originating from 22 countries worldwide to update their knowledge and discuss radiation research issues through 118 oral and 44 poster presentations. In addition, the MELODI 2013 workshop was reaching out to the broader radiation protection community, rather than only the low-dose community, with contributions from the fields of radioecology, emergency and recovery preparedness, and dosimetry. In this review, we summarise the major scientific conclusions of the workshop, which are important to keep the MELODI strategic research agenda up-to-date and which will serve to establish a joint radiation protection research roadmap for the future. [ABSTRACT FROM AUTHOR]

The author discusses the need of radiation protection focusing on the situation post Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011. He argues that the radiation protection system has become complex and faces communication barrier in order to be conveyed to the general public. He suggests several changes in the radiation protection system such as proper communication of Linear no-threshold (LNT) hypothesis and presenting a relevant to communicate radiation risks.

The International Commission on Radiological Protection (ICRP) created a Task Group (ICRP TG84) on the initial lessons learned from the nuclear accident at the Fukushima Dai-ichi NPPs vis-à-vis the ICRP system of radiological protection. The ICRP TG84 is expected to compile lessons learned related to the efforts carried out to protect people against radiation exposure during and after the emergency exposure situation caused by the accident and, in light of these lessons, to consider ad hoc recommendations to strengthen the ICRP system of radiological protection for dealing with this type of emergency exposure. The Chairman of ICRP TG84 presents in this paper his personal views on the main issues being considered by the group at the time of the Fukushima Expert Symposium. ICRP TG84 expects to finalize its work by the end of 2012. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]