March 30, 2011 10:22
The decision to prevent a meltdown at the Fukushima nuclear power plant by pouring seawater on the reactor has put the Japanese government in a terrible dilemma.
Its original plan was to cool the reactors with seawater as the plant's cooling systems was damaged in the earthquake, lower radiation levels, allowing workers to fix the damaged equipment, and normalize the operation. But things have not gone as planned, and after two weeks, it has realized that the seawater poured into the water tank housing spent nuclear fuel rods as well as the cores of the troubled reactors is contaminated and left sitting near the facilities.
On Monday, as much as 1,000 mSv of radiation per hour was detected in the 4,000 to 5,000 of water that filled the drainage tunnels near the turbine room.
The reactor core and the drainage system linking it with the turbine were damaged in the earthquake, causing contaminated water to seep out. Unless the contaminated water is removed from the drainage tunnels, restoration work cannot proceed, but workers still need to keep pumping more water into the reactors to keep them from overheating.
On Tuesday, temperature readings on the surface of the reactor's outer shell began to surge, prompting officials to pour more water onto it. The bind is that pumping in more water will lead to the seepage of heavily contaminated water, but stopping could cause a core meltdown. Now it appears the core has already melted through the bottom of its containment vessel and on to the concrete floor, while the fuel remains partially exposed in all three stricken reactors.
Officials are saying they should have used water sparingly in order to minimize seepage.
But the damage is done, and there is mounting criticism of the Japanese government's response at the initial stage of the crisis, such as refusing the aid of other countries.
Meanwhile, France has agreed to send two nuclear experts to help restoration efforts at the power plant. France's Environment Minister Nathalie Kosciusko-Morizet said Tuesday one nuclear expert from Areva and another from the state-run CEA nuclear research body are being sent to Japan at Tokyo's request. The two are experts in the pumping and treatment of radioactive water.
- Copyright © Chosunilbo & Chosun.com