Title: Inquiry Into Fukushima Plant Suggests Worse Damage
Author: HIROKO TABUCHI
Date: March 29, 2012
The damage to the core of at least one of the meltdown-stricken reactors at Fukushima could be worse than previously thought, raising new concerns over the plant’s stability and complicating the post-disaster cleanup, a recent internal investigation has shown.
[...] Officials at Tepco had previously said that operation was succeeding, and that the damaged fuel rods were safely submerged in water.
But earlier this week, an examination at one of the reactors showed the water level at its core to be lower than levels previously estimated, raising fears that the broken-down remnants of the uranium fuel rods there may not be completely submerged and in danger of heating up again.
Cooling water at the plant’s No. 2 reactor came up to just two feet from the bottom of the reactor’s containment vessel, a beaker-shaped structure that encases the fuel rods. That was below the 33-foot level estimated by officials when the government declared the plant stable in December. [...]
Where’s the Water Going?
The low water levels also raise concerns that radioactive water may be leaking out of the reactor at a higher rate than previously thought, possibly into a part of the reactor known as the suppression chamber, and into a network of pipes and chambers under the plant — or into the ocean.
At the No. 2 reactor, workers still pump about nine tons of water an hour into the core to keep it cool.
Kazuhiko Kudo, a professor of nuclear engineering at Kyushu University in southwestern Japan
- [Kudo] said it was now suspect whether the nuclear fuel was being adequately cooled. And if some parts of the fuel remained above water, there was a risk that the fuel could again heat up and melt. That could set off a dangerous spike in the pressure inside the containment vessel, and lead to more radiation escaping the reactor, he said.
- “The plant is still in a precarious state”
- “Unfortunately, all we can do is to keep pumping water inside the reactors and hope we don’t have another big earthquake”
Read the report here
Published: March 29th, 2012 at 7:37 pm ET