March 22, 2011

1. Purpose of the sea area monitoring plan

A monitoring survey will be implemented in the sea area in order to identify the status of release of radioactive substances from the Fukushima Dai-ichi Nuclear Power Station.

2. Sea area monitoring action plan

A research vessel of the Japan Agency for Marine-Earth Science and Technology will measure the air dose rates over and collect seawater samples from the coastal waters near the nuclear facility. The seawater samples collected will be brought back and sent to the Japan Atomic Energy Agency for analysis.

(Action plan)

  • Measuring sites: Seawater samples will be collected in the same sea area as that subject to the conventional project for comprehensive evaluation of marine environmental radioactivity. The measuring sites will be approximately 30 km off the coast (the air dose rates will be measured; a sufficient distance away from the facility for securing the safety of the vessel crew). Seawater will be collected at eight locations running parallel to the coastline at approximately 10 km intervals, and the data will be compared with that obtained in past surveys.

3. Monitoring schedule

March 22, 2011 Research vessel departs

March 23, 2011 Seawater is collected

The time required for the measuring will vary depending on the concentration level, etc.

The results are planned to be released around March 24, 2011.

4. Monitored items

(1) Radioactivity concentrations in the seawater

(2) Air dose rates over the sea

(3) Radioactivity concentrations in airborne dust over the sea

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(Emergency Operation Center)