#Fukushima I Nuke Plant: High Radiation from Equipment in Reactor 4?

There's a possibility that the equipment in the "Pit" on the upper floor of the Reactor 4 reactor building may be emitting the high level of radiation because the water that had covered and shielded the equipment drained to the Reactor Pressure Vessel (RPV) that was in maintenance and to the Spent Fuel Pool when the earthquake hit on March 11.

From Kyodo News Japanese (6/19/2011):

東京電力福島第１原発４号機の原子炉建屋上部にあり、機器を水に漬けて保管している「ピット」という場所の水位が低下、水による放射線遮蔽効果がなくなり、露出した機器から強い放射線が出ている可能性が高いことが１９日、分かった。

It was revealed on June 19 that it is highly possible that the water level in the "Pit" that stores equipment on the upper floor of the Reactor 4 reactor building decreased, exposing the equipment stored in the pit which is emitting a high level of radiation.

　４号機は地震発生時に定期検査中だったが、地震と津波で冷却機能が失われ、使用済み燃料プールの水が燃料の熱で蒸発して水位が低下。プールにつながるピットの水位も低下したとみられる。

The Reactor 4 was in regular maintenance when the earthquake hit. The cooling system was lost due to the earthquake and tsunami, and the water in the Spent Fuel Pool evaporated and the water level decreased. At the same time, the water level of the Pit, which is connected to the Spent Fuel Pool, probably decreased.

　東電は「４号機の建屋周辺の放射線量は特に高くなく、外部への影響はない」とするが、今後、この付近で作業する場合に備えて水位を上げるため、１９日から水の注入を始めた。

TEPCO said that "the radiation level around the Reactor 4 building is not particularly high, and there is no effect on the environment", but the company started injecting water in the Pit on June 19 to raise the water level in preparation for any future work near the Pit.

The diagram is from Kyodo. The Pit is on the left, the Spent Fuel Pool on the right. The dotted blue line at the top was the water level of the Pit when the earthquake hit.

　福島第１原発４号機のピットの水位が下がった状況

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