US, Japan develop new method for radiological dose assessment in area surrounding Fukushima Daiichi nuclear power plants

The National Nuclear Security Administration (NNSA) and the Japan Atomic Energy Agency (JAEA) have developed a novel method for analyzing airborne radiological monitoring data. This new method has been used to perform a detailed study of survey data taken by the NNSA and JAEA in the months following the March 2011 radiological incident in Japan.

Aerial surveys were employed in the region surrounding the stricken Fukushima Daiichi Nuclear Power Plant to cover the area impacted by the accident quickly, thoroughly and safely. This new analysis provides a complete map of Iodine-131 (I-131) deposition. I-131 is an important contributor to radiological dose and its concentration was uncertain during the incident due to its short half-life and the complexity of the analysis. A map of I-131 deposition is a critical step in order to conduct accurate exposure assessments, population dose reconstruction and follow-up epidemiological studies.

Results of the analysis will be released in the August issue of the Health Physics journal.

"Collaborations with international experts are important to improve our capability to respond to nuclear emergencies," said David Bowman, Director of NNSA's Office of Emergency Response. "This technical exchange with the Japanese improves their understanding of the ramifications of the accident, and at the same time enhances our ability to respond domestically should the need arise."

NNSA's Office of Emergency Operations currently collaborates with more than 80 foreign governments and 10 international organizations with projects ranging from providing assistance to foreign governments in improving their emergency preparedness and response programs, to joint collaborative activities to improve emergency management infrastructure worldwide.