Robots measure elevated levels of radiation inside Fukushima reactor 3

[News_Editor]

Robots measure elevated levels of radiation inside Fukushima reactor 3

2011-04-19 00:13:08 GMT+7 (ICT)

TOKYO, JAPAN -- Japanese nuclear authorities on Monday informed that remotely operated robots measured elevated levels of radiation (up to 57 millisieverts per hour) inside the reactor 3 of the Fukushima Daiichi nuclear power plant, the Japan Times reported.

The U.S.-made PackBot ground robots were deployed to measure radioactivity levels in the 3 reactors of the Fukushima plant in order to determine if it was safe for workers to go inside to conduct critical repairs of the damaged cooling systems.

The robots also took measurements of radiation, temperature, humidity and oxygen levels in the buildings. On Monday, the robots manufactured by iRobot were sent to Fukushima's reactor 2 building.

In the reactor 3 building, the U.S. robots detected a radiation level between 28 to 57 millisieverts per hour on the ground floor, while on reactor 1 building radioactivity was between 10 to 49 millisieverts per hour.

The international standard for worker exposure to radiation is 500 millisieverts per year for emergencies. NISA allowed a temporary limit of 250 millisieverts per year due to the current situation.

Japan's Nuclear and Industrial Safety Agency (NISA) is currently considering installing French-style air coolers. The new system will cool water to be stored inside the reactors' containment vessels.

The new cooling-system is similar to an air conditioner used for French nuclear power plants. It will be the first of its type to be installed in Japanese reactors which use water-based cooling systems.

The French system will remove heat from the coolant water that will circulate inside the containment vessel and keep the reactor's core cool. However, the installation will take between six to nine months and will be conducted by Tepco.

On Tuesday, NISA upgraded the severity level of the ongoing nuclear crisis from an international scale level 5 to a level 7, matching 1986's Chernobyl crisis. The evaluation was based on an estimated amount of radioactive material released into the external environment.

The nuclear station was damaged after the powerful earthquake and tsunami on March 11 in which more than 27,000 people were killed and missing in northeastern Japan. The disasters disabled the cooling systems of the Fukushima Daiichi nuclear power plant. Radioactive elements leaked into the sea and were later found in water, air and food products in some parts of Japan.

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