• The Associated Press


The effort to steer the Fukushima No. 1 nuclear power plant away from disaster suffered another setback when workers discovered widespread uncontrolled leaking of radioactive water at the six-reactor complex.

What’s new about this?

Since the March 11 tsunami knocked out power, plant workers have been intentionally venting radioactive steam into the air to keep overheated reactor cores from bursting. Radioactive steam has also gone aloft from overheated storage pools for used fuel.

Now radioactive water has also been discovered at the bottom of turbine buildings adjacent to the 1 and 3 reactor buildings. Similar flooding in 2 and 4 is being checked; it is also probably radioactive.

Where did this radioactive water come from?

Plant officials and government regulators say they don’t know.

It could come from more than one source: a leaking reactor core, associated piping or a spent fuel pool, of which there are seven. Officials won’t even rule out the idea that it may have come from overfilling the pools with emergency cooling water.

The flooding is deepest in the reactor No. 3 building — where it is waist-high — and may have flooded basement areas in other buildings. Equipment in the reactor 3 building could have sprung a leak March 14, when a powerful hydrogen gas explosion blew apart that unit’s reactor building.

Does the leaking water make meltdown more likely?

Probably not at the current rate of leakage.

The fuel rods inside units 1, 2 and 3 are believed to have partially melted down already.

However, with desperate efforts to keep the units cool using seawater, temperatures in recent days have stayed well within a safe zone at all the reactors. If these conditions prevail, there will be no further core melting, despite leakage. The temperatures of the spent fuel pools also have been under control, but occasional spikes have spurred worry.

So why should we care about the leaking?

For one thing, it puts more radioactive contamination into the environment, probably mostly into the ground and sea.

It could add more radiation exposure to people near the plant. It has stalled work to restore in-house cooling systems needed to keep the plant safe in the long term.

Perhaps the leaking comes from cooling equipment that must be repaired before other work can advance.

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