Restore cooling function to stop nuclear plant leaks

Tokyo Electric Power Co., the operator of the crippled Fukushima No. 1 nuclear power plant, has begun releasing water containing low-level radioactive substances from the plant into the Pacific Ocean.

The company said that it is an emergency measure to free up space at the plant for water contaminated with high levels of radioactive material.

Radioactive water equivalent to the volume of five or six 50-meter-long swimming pools will be discharged into the sea. Though this water reportedly has been contaminated with only low levels of radioactive substances, it still contains radioactive iodine up to 500 times more than the legal limit in seawater.

Having to resort to this step is extremely unfortunate. We urge the government and TEPCO to do everything they can to control the situation so the amount of contaminated water to be released into the sea is kept to the absolute minimum.

About 500 tons of water are being poured every day into the plant's Nos. 1-3 nuclear reactors to prevent nuclear fuel from overheating. Some of this water is leaking from the damaged reactors and accumulating in large pools at the nuclear complex.

Water must be removed

Most problematic is the water that accumulated in the basement of the No. 2 reactor turbine building and the tunnellike trench connected to it.

This water contains levels of radioactive substances 2 million times higher than the contaminated water being dumped at sea.

It must be pumped out quickly and stored safely in tanks and the other containers. The discharge of the less contaminated water into the ocean is a last-ditch measure to make space in the tanks for highly contaminated water.

Worryingly, some highly contaminated water has already leaked from the turbine building into the sea. TEPCO has been trying to find where and how this water leaked into the sea and to plug the leak.

The utility has been struggling to complete this work, but finding the source of the leak--and stopping it--must be done quickly.

The government and TEPCO said water with low-level radiation being released into the sea will gradually disperse and have only minimal effects on human health.

However, many people are still worried about this situation because highly radioactive water is still pouring into the ocean. There are concerns the fishing industry could be brought to its knees.

Much hinging on next month

The government should further tighten inspections of marine products to determine whether they are being affected by the radioactive contamination, and properly evaluate what levels of contamination are safe.

It is also essential that inspection results be quickly disclosed and explained in detail to the public.

The discharge into the ocean could free up enough space in the tanks to store nearly one month's worth of highly radioactive water, even if water injections into the reactors continue at their current pace.

This one month is very important.

We hope the reactors will be brought under control--with cooling water circulating to prevent nuclear fuel from overheating--during this period.

If the contaminated water is pumped out from the nuclear plant, work to restore crucial circulation pumps is expected to make progress.

Meanwhile, the government and TEPCO should tap the wisdom of nuclear experts in Japan and abroad, and prepare several options for any recurrence of difficulties at the nuclear plant.

They also should push ahead with efforts to deal with radiation-laced water, such as constructing additional storage tanks and acquiring materials that absorb radioactive substances.

-The Yomiuri Shimbun/Asia News Network