Measures against Recriticality and Future Earthquakes and Tsunamis

< Recriticality >

When criticality occurs, Xe-135 and other noble gases increase in an unexpected fashion. At the Fukushima Daiichi NPS, generation of noble gases is being monitored at all hours. At present, the amount of noble gases has been stable, which suggests that recriticality has not occurred. However, in preparation for any risks of recriticality, a boric acid water system to suppress nuclear fission in the event of criticality has been installed.

< Measures against earthquakes and tsunamis >

As measures against any earthquakes and tsunamis of the same level as the Great East Japan Earthquake, a temporary seawall has been constructed and the work to block openings of the buildings has been underway to prevent inflow of seawater in the event of a tsunami. Additionally, backup power sources such as emergency power supply vehicles and water injection means such as fire engines are placed at a higher area where tsunamis are unlikely to reach.

• Included in this reference material on February 28, 2018