Two experts from the International Atomic Energy Agency will join seawater monitoring activities off the Fukushima No. 1 power plant on Thursday and Friday, according to the U.N. nuclear watchdog.
The two marine monitoring experts from the Marine Environment Laboratories in Monaco, on a week-long tour to Japan through next Tuesday, will check seawater sampling and data analysis.
They arrived in Japan on Wednesday.
The experts will also meet with officials from the government, which had asked that they be dispatched.
Their findings will be reported to a planned IAEA mission due to visit Japan later this month for a peer review of plans to decommission reactors 1 through 4 at the plant.
The experts are David Osborn, director of Environment Laboratories in Monaco, and Hartmut Nies, head of the Radiometrics Laboratory, it said.
"One of the focuses of the mission is the contaminated water issue," the agency said.