Follow-Up of Occupational Health Issues and Measures Taken in Fukushima Daiichi Nuclear Power Plant Where Decommissioning Work Has Continued Over 6 Years Since 2014.

Objectives: To follow up arising occupational health (OH) issues, measures taken, and their performances in the Fukushima Daiichi Nuclear Power Plant since 2014, and thus share experiences and extend the contribution of OH to long-term decommissioning work and preparation for future disasters.

Methods: Necessary information from official reports and through the OH-related activities involved was collected and analyzed.

Results: The issues were categorized into establishment of the OH management system, three individual issues, and others.

Assessing the effect of mandatory progress reporting on treatment requirements identified during health examinations at the Fukushima Daiichi Nuclear Power Plant: A time series analysis.

Objectives: At the Fukushima Daiichi Nuclear Power Plant, run by the Tokyo Electric Power Company, new procedures were introduced as part of the fitness for duty program in July 2016. These were designed to ensure that treatment and further investigations identified as necessary during health examinations were carried out. This study aimed to assess the effectiveness of the initiative by testing whether workers who needed further health examinations obtained them promptly, and whether the number with unmet health needs decreased and the number of workers being treated increased.

Continuous improvement of fitness-for-duty management programs for workers engaging in stabilizing and decommissioning work at the Fukushima Daiichi Nuclear Power Plant.

Background: Numerous workers have participated in recovery efforts following the accident that occurred at the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant after the Great East Japan Earthquake. These workers, belonging to various companies, have been engaged in various tasks since the accident. Given the hazards and stress involved in these tasks and the relatively long time required to transport sick or injured workers to medical institutions, it became necessary to quickly implement a more stringent management program for fitness for duty than in ordinary work environments.

Prolonged increase in T-cell receptor (TCR) variant fractions of spleen T lymphocytes in pregnant mice after gamma irradiation.

To investigate the relationship between the radiation-induced increase of T-cell receptor (TCR) defective variant fractions and physiological status such as pregnancy, C57BL/ 6N mice were irradiated with 3 Gy of gamma rays at various days of gestation, just before and just after pregnancy. While the highest level of variant fractions in spleen T lymphocytes appeared at 9 days postirradiation and resolved fairly rapidly for nonpregnant mice, the increased variant fractions for pregnant mice irradiated at 16.5 days of gestation reached a plateau at 14 days postirradiation and remained at high levels until 28 days after irradiation.

The delayed manifestation of T-cell receptor (TCR) variants in X-irradiated mice depends on Trp53 status.

The influence of Trp53 on the radiation-induced elevation of T-cell receptor (TCR) variant fractions was examined in splenic T lymphocytes of Trp53-proficient and -deficient mice. Wild-type Trp53+/+, heterozygous Trp53+/- and null Trp53-/- mice were exposed to 3 Gy of X rays at 8 weeks of age. The fraction of TCR-defective variants was measured at various times after irradiation.