Nigeria Content Online

Japanese authorities
have taken a major step in managing a nuclear crisis by connecting all
six earthquake-damaged reactors to power supply.

But it’s too soon to say the crisis has reached a turning point, experts said on Monday.

Power has been
connected but not switched on to crank up most coolers and pumps, which
may have been badly damaged in the quake and tsunami that on March 11
triggered the world’s worst nuclear accident since Chernobyl. Only one
pump has been activated. The damaged reactors and their spent fuel pools
at the Fukushima Daiichi nuclear power plant, 240 km North of Tokyo,
urgently need cooling from air-conditioners and from water pumped in.

U.S. Energy
Secretary, Steven Chu, asked by CNN whether the worst of Japan’s 10-day
nuclear crisis was over, said: “Well, we believe so, but I don’t want to
make a blanket statement.” U.S. Nuclear Regulatory Commission Chairman,
Gregory Jaczko added that radiation levels at the plant appeared to be
falling.

But nuclear experts in the U.S. and elsewhere were not quite as positive.

“I am not sure if
the crisis has passed but it is definitely a step in the right
direction,” said Peter Hosemann, a professor at the University of
California Berkeley’s Nuclear Engineering Department.

“It is getting
better. However, we don’t know if the pipes and connections and pumps
still work at this point or what works and what not. But having power
makes external water supply easier.” At Fukushima, 300 engineers have
worked around the clock inside an evacuation zone to contain the worst
nuclear accident since Chernobyl, Ukraine, in 1986.

The most badly damaged reactors are No. 3 and 4, which were both hit by explosions last week.

Japan’s nuclear
safety agency said pressure was rising in the most threatening reactor,
No. 3, which contains highly toxic plutonium, and this may have to be
released by “venting” steam, a step taken last week that discharged low
levels of radiation into the atmosphere.

Japanese authorities say they have established power lines to all the reactors.

Reactors 5 and 6
have not been much of a problem since a diesel pump was activated last
week, cooling down both the reactors and their spent fuel ponds.

“Reactors 5 and 6,
they are now in what’s called cold shutdown, and the spent fuel cooling
ponds are at normal temperatures,” said Tony Irwin, a former nuclear
plant manager who now lectures at Australian National University.

“They are in the
sort of situation now we would like to see 1, 2, 3 and 4 in.” The other
reactors are damaged but more or less stable, although the spent fuel
cooling pond at reactor 4 is also a particular worry.

The reactor’s core was drained only last November and the radioactive spent fuel transferred to the pond.

“There was already spent fuel in there so there was quite a high load of spent fuel in that pond,” said Irwin.

“And that has been
giving the main radiation effects on site.” He said of the efforts at
the plant: “I think it’s all going in a good direction, but we are not
at a point where we can say we are totally happy.” Engineers have been
spraying the coastal complex with thousands of tonnes of sea water so
fuel rods would not overheat and emit more radiation.

Najmedin Meshkati, a
nuclear and environmental expert at the University of Southern
California Los Angeles, said the measures were necessary but raised a
fresh, and serious, concern.

“Where does the sea
water drain?” he asked. “This is now radioactive waste water. Has there
been any measurement of its radiation effect?

“I am interested to
know how this water is being disposed, if it is being disposed or just
allowed to drain to sea. That is the hidden part of this catastrophe.”
Japanese authorities have acknowledged that some of the water may be
spilling into the ocean, but said they doubted it would have any effect
on human health.

They agreed it needed to be monitored.

Overall, however, experts were more optimistic than they were earlier in the crisis.

“My read is, that they’re at least holding their own,” said Murray Jennex, professor at San Diego State University, California.

“Things are not getting worse. That’s actually good news right now.
The longer they go, the cooler the stuff starts to get, and the less
likely there is to be a severe problem.”