POWER May 2011 - 8

The Battle to Stabilize Daiichi
Weeks after a massive magnitude 9.0 earthquake and subsequent
14-meter-high tsunami devastated Fukushima Prefecture in northeastern
Japan, workers from the Tokyo Electric Power Co. (TEPCO)
were still struggling to regain control of four severely damaged
reactors at the six-unit Fukushima Daiichi nuclear power plant.
As of press time, more than 370 workers have been working
around the clock to quell the crisis-the world's worst since
Ukraine's Chernobyl disaster in 1986 (see the cover story). However,
no end is in sight.
At the beginning of April, when 28,000 people were thought
dead or missing in northeastern Japan, two TEPCO workers-
Kazuhiko Kokubo, 24, and Yoshiki Terashima, 21-were the only
confirmed fatalities at the plant. The workers, whose bodies were
recovered in the basement level of Unit 4's turbine hall, were
thought to have died from multiple injuries sustained while conducting
regular checks when the earthquake hit.
Twenty-one workers have so far been exposed to radiation doses of
over 100 millisieverts-far exceeding the 50 millisieverts annually allowed
by the U.S. Nuclear Regulatory Commission for adults working
with radioactive material. Japanese authorities expanded the authorized
threshold for radiation exposure to 250 millisieverts from the
prior 100 millisieverts level set for emergency circumstances, but no
one has been exposed to levels that high (Figure 1).
As of early April, engineers had managed to trace and plug a
hole leaking highly radioactive water into the Pacific Ocean from
a seaside pit at Unit 2, where, as in Units 1 and 3, fuel rods have
partially melted.
Meanwhile, TEPCO continued disposal of 11,500 tons of water
tainted with low levels of radioactivity from the radioactive
waste treatment plant and sub-drain pits of Units 5 and 6 to
make room for water with higher levels of radioactivity.
TEPCO also began injection of 6,000 cubic meters of nitrogen at
Unit 1, where, 14 days after the disaster, temperatures reportedly
surged to 400C, exceeding the unit's design value of 302C. Nitrogen
injection to displace oxygen and reduce the risk of another hydrogen
explosion will also be carried out at Units 2 and 3.
1. Suited up. In this photo, taken March 18, workers engaged in
connecting the Fukushima Daiichi plant to the offsite power grid wear
protective gear necessitated by elevated radiation levels near the damaged
nuclear power facility. Courtesy: TEPCO
At Unit 1-which was rocked by what TEPCO calls an " assumed "
hydrogen explosion on March 12, a day after the massive
quake-injections of seawater into the reactor have been
replaced by freshwater additions, first via a temporary motordriven
pump and then by a motor-driven pump powered by an
offsite transmission line.
At Unit 2-where the situation is more critical after an explosion
is thought to have occurred on March 15 in the pressure
suppression chamber, causing severe damage to the core and fuel
integrity-TEPCO has replaced injections of seawater with boric
acid-laced freshwater.
Freshwater is also being pumped into Unit 3, a reactor that
has used mixed oxide fuel since September and where a March 14
explosion left the unit's spent fuel tank exposed.
An explosion also occurred at Unit 4 on March 15. That unit
had been shut down for routine inspection before the quake,
but its fuel rods, stored in the spent fuel pool, were left without
cooling water circulation to remove decay heat. For days,
Japan's defense force and TEPCO battled to cool down the spent
fuel pools at Units 3 and 4, dumping seawater into the units by
helicopter and riot-control water cannons. Periodic spraying continues
at Unit 4's spent fuel pool. The spent fuel pools at Units 5
and 6 are showing decreasing temperatures, and both units have
reached cold shutdown.
The disaster has rattled Japan's largest power utility, and its
financial future is uncertain, as questions have been raised about
its ability to pay mushrooming costs in the aftermath of the
March 11 quake and tsunami. With the loss of Daiichi and other
plants, TEPCO is struggling to meet power demand. Damage at
four reactors of the crippled nuclear plant have rendered them
useless; decommissioning could take three decades and cost up
to 1 trillion yen (US$12 billion), TEPCO Chair Tsunehisa Katsumata
has said.
Then, there are compensation costs. Though Japanese law exempts
utilities from compensation for nuclear accidents caused
by natural disasters, the government said it is " impossible " that
TEPCO's liability for the accident would be easily dismissed. And
TEPCO itself in early April said it would consider payments to disaster
victims, costs that could top US$130 billion if the crisis is
prolonged, according to estimates from Bank of America-Merrill
Lynch. TEPCO's stock hit a 47-year low on April 6, at which point
it had lost 82% of its pre-accident value.
It is unclear how much full cleanup will cost, though the consensus
is that total costs will be staggering. The world's top
insurers have said the disaster will cost them $5 billion, although
risk-modeling agencies suggest the overall cost to insurers could
be as much as $30 billion. Calming fears of immediate bankruptcy,
in early April, Japan's major banks considered extending
loans worth 2 trillion yen (US$24 billion) to TEPCO, and the
Japanese government has not ruled out injecting capital into the
beleaguered utility.
China's Five-Year Plan Is Heavy on
Non-Fossil Generation
The People's Republic of China's Congress approved a much-anticipated
draft of the country's 12th Five-Year Plan (2011-2015)
on March 14. Along with key objectives that included boosting
its gross domestic product (GDP) by 7% annually on average, the
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POWER May 2011

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