[en] To understand the current situation of internal radiation exposure in the population around the Chernobyl Nuclear Power Plant (CNPP), we examined the ¹³⁷Cs body burden in six residents of Belarus, Ukraine and Russia in 2002 and 2004 using the whole-body counter (WBC) at Nagasaki Univ. (Japan). The data were compared with those of our previous study performed in 1993-1994 using the same method. In 2002 and 2004, peaks of ¹³⁷Cs were detected in two residents from Gomel, which was heavily contaminated by the CNPP accident, one from Minsk (Belarus) and one from Kiev (Ukraine), but another resident from Minsk showed no ¹³⁷Cs peaks. The results of the present study suggests that residents around the CNPP are still exposed to chronic ¹³⁷Cs internal irradiation, probably due to the daily consumption of contaminated domestic foods, but the risk of any disease by the irradiation is quite low. Long-term follow-up of WBC around the CNPP is useful and may contribute to radiation safety regulation together with a reduction of unnecessary radio-phobia for the residents. (authors)

[en] An FEM analysis program which can predict FIV (flow-induced vibration) in piping system solving fluid-structure interaction is developed. This program solves the relationship between fluid vibration source (pump, orifice, etc.) and piping vibration by coupling fluid and pipe structure together. A present evaluation method of flow-induced vibration is based on conventional design methods with excessive margin or on the rules having been cumulated in the past plant experiences. Therefore the countermeasures based on the measurement of vibrations in start-up tests are very important. In such methods, the phenomena of flow-induced vibrations are not accurately predicted but sometimes conservatively evaluated. This newly developed program provides the function to predict the influence of fluid pulsations on piping vibrations. In this paper, the development and application result of the program are presented

[en] Radiological specialists from Nagasaki University have served on the medical relief team organized at Fukushima Medical University Hospital (Fukushima City) ever since the accident at the Fukushima Dai-ichi nuclear power plant. Furthermore, we have conducted the radiation crisis communication efforts by spreading correct information on the health effects of radiation as 'advisors on radiation health risk control'. Nagasaki University has been assisting the reconstruction efforts of Kawauchi Village in Fukushima Prefecture, which was the first village to declare that residents could safely return to their homes because radiation doses were found to be at comparatively low levels. In April 2013, Nagasaki University and the Kawauchi government office concluded an agreement concerning comprehensive cooperation toward reconstruction of the village. As a result, we established a satellite facility of the university in the village. In conclusion, training of specialists who can take responsibility for long-term risk communication regarding the health effects of radiation as well as crisis communication in the initial phase of the accident is an essential component of all such recovery efforts. Establishment of a training system for such specialists will be very important both for Japan and other countries worldwide. (authors)

[en] The Great East Japan Earthquake in March 2011 destroyed the Fukushima Dai-ichi Nuclear Power Plant (FNPP) and almost all residents in a 20 km radius from the plant eventually evacuated. FNPP reactors were stabilised in December 2011; some evacuees decided to return to their hometowns, and the other evacuees remained. Efforts were made to identify the determinants that affect the decision to return home in order to promote recovery of the surrounding area of FNPP. Seventy one residents who had not returned to hometown and 56 residents who had returned were selected. Logistic regression analysis adjusted for confounding factors showed that being female [odds ratio (OR): 2.43, p=50.03], living in areas with relatively higher ambient doses (OR: 3.60, p=50.01) and expressing anxiety over radiation exposure (OR: 8.91, p < 0.01) were independently associated with decisions not to return. Results of this study suggest the importance of active participation by scientists and local authorities in communicating the risk to the general population involved in returning home. (authors)

[en] The relationship between the reported ambient dose equivalent (H^*(10)) and the individual dose rate recorded by medical staff in Fukushima City after the accident at the Fukushima Daichi nuclear power plant was evaluated, following a 9.0-magnitude earthquake that struck the east coast of Japan. Personal dose equivalent (H_p(10)) ranged from 0.08 to 1.63 μSv h^-1 and H^*(10) ranged from 0.86 to 12.34 μSv h^-1. H_p(10) from March to July 2011 were significantly lower than H^*(10). The relationships between these dose equivalents were moderately correlated. The regression equation was calculated as follows: H_p(10)=0.0696xH^*(10)+0.0538. The preliminary data of this study show that, in Fukushima, the individual dose is much lower than that determined H^*(10). It is important to evaluate H_p(10) in order to lessen the anxiety of the general population in Fukushima. (authors)

[en] Whole-body counters (WBCs) are special instruments for measuring internal irradiation doses and are usually housed within or around nuclear facilities in the event of unexpected radiation emergencies. As a substantial proportion of total body potassium (TBK) is found in fat-free mass (FFM), FFM volume can be predicted from WBC-measured ⁴⁰K. We screened TBK in Japanese healthy young adults using a WBC and found strong linear correlations between TBK and lean body mass (LBM) and body mass index (r = 0.97, P<0.01 and r = 0.47, P<0.01, respectively). Multiple linear regression analysis, following adjustments for sex, indicates that only LBM has a significant correlation with TBK (P<0.01). These results strongly support the feasibility of using WBCs for estimating FFM. (authors)

[en] Lessons from the Fukushima-Daiichi nuclear power plant accident emphasize the difficulties for restoring the socio-economic activities in the affected areas. Among them, a series of radiological protection challenges were noted, in particular concerning the protection of employees, the securing of the production and the guarantee provided to consumers of the radiological monitoring of products to restore their confidence. Based on case studies reporting the experience of employers deploying their activities in affected areas, an analysis of these radiological protection challenges has been performed. Characterizing the radiological situation was not always straightforward for the managers. With the help of radiological protection experts, protective actions have been identified and specific efforts have been devoted to provide information to employees and their families helping them to make their own judgement about the radiological situation. Respecting the decisions of employees and developing a radiological protection culture among them have proved to be efficient for restoring the business activities. Continuing or restoring the production not always manageable. It requires to develop dedicated radiological monitoring processes to ensure the radiological protection of workers and the quality of the production. Re-establishing the link with the consumers and organising the vigilance on the long-term were necessary for companies to maintain their production or develop new ones. Deploying a socio-economic programme for ensuring the community resilience in affected areas requires the adoption of governance mechanisms respecting ethical values to ensure the overall objective of protecting people and the environment against the risks of ionizing radiation and contributing to provide decent living and working conditions to the affected communities. It is of primary importance to rely on the involvement of local communities in the elaboration and deployment of the socio-economic activities with due considerations for ensuring the integrity of the communities, and respecting their choices. (authors)

[en] South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2x7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y^-1. From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g^-1 of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y^-1 ranging from 2.79 to 14.17 mSv y^-1. (authors)

[en] The actual implementation of the epidemiological study on human health risk from low dose and low-dose rate radiation exposure and the comprehensive long-term radiation health effects survey are important especially after radiological and nuclear accidents because of public fear and concern about the long-term health effects of low-dose radiation exposure have increased considerably. Since the Great East Japan earthquake and the Fukushima Daiichi Nuclear Power Plant accident in Japan, Fukushima Prefecture has started the Fukushima Health Management Survey Project for the purpose of long-term health care administration and medical early diagnosis/treatment for the prefectural residents. Especially on a basis of the lessons learned from the Chernobyl accident, both thyroid examination and mental health care are critically important irrespective of the level of radiation exposure. There are considerable differences between Chernobyl and Fukushima regarding radiation dose to the public, and it is very difficult to estimate retrospectively internal exposure dose from the short-lived radioactive iodines. Therefore, the necessity of thyroid ultrasound examination in Fukushima and the intermediate results of this survey targeting children will be reviewed and discussed in order to avoid any misunderstanding or misinterpretation of the high detection rate of childhood thyroid cancer. (authors)

[en] To determine the current risk of internal radiation exposure after the Chernobyl accident, the ¹³⁷Cs body burden of the inhabitants of Bryansk Oblast (Russian Federation) was evaluated, from 1998 to 2008. The study population is composed of 84 666 people who visited Bryansk No. 2 Hospital. A whole-body counter was used for measurement of ¹³⁷Cs body burden. ¹³⁷Cs concentration was significantly higher in the late period during the study and showed seasonal variation, suggesting that inhabitants may have consumed contaminated forest products. However, people with high annual exposure doses were quite rare during all years of the study. In conclusion, although internal radiation exposure from ¹³⁷Cs continues to this day in Bryansk Oblast, the annual exposure dose is low in almost all inhabitants. Because of the long half-life of ¹³⁷Cs, the long term follow-up is necessary to monitor the health status and relieve the anxiety of the inhabitants around Chernobyl. (authors)