Japan To Report Nuclear 'Melt-Throughs' To UN
June 7, 2011
TOKYO - Japan
in a report prepared for the UN nuclear watchdog on Tuesday
said for the first time that fuel in its crippled Fukushima
plant may have melted through three reactor core vessels.
months after the massive March 11 seabed quake and tsunami
sparked the world's worst nuclear accident since Chernobyl,
Tokyo also promised to tighten its nuclear industry safety
standards and mechanisms.
Prime Minister Naoto Kan, approving the 750-page report,
said that "above all, it is most important to inform the
international community with thorough transparency in order
for us to regain its confidence in Japan."
Japan is due
to submit the report to the UN International Atomic Energy
Agency (IAEA), which sent its own multinational fact-finding
team to Japan and is due to discuss the disaster at its
Vienna headquarters this month.
The document was released a day after Japan more than
doubled its earlier estimate of total radiation released
into the air from the plant in the first days after the
tsunami knocked out its reactor cooling systems.
Japan's Nuclear and Industrial Safety Agency (NISA) now says
it believes 770,000 terabecquerels escaped into the
atmosphere in the first six days — compared to its earlier
estimate of 370,000 terabecquerels.
NISA's revised radiation figure is likely to fuel criticism
of the initially slow and vague flow of information from the
Kan government and embattled plant operator Tokyo Electric
Power Company (TEPCO).
estimate is closer to that of Japan's independent Nuclear
Safety Commission which had initially estimated a release at
630,000 terabecquerels in the first month after the 14-metre
(46-foot) ocean wave crashed into the plant.
NISA also said in its review that it believes much of the
nuclear fuel inside three reactors melted down faster than
TEPCO has said it believes the molten fuel is now being
cooled by water at the bottom of the number one, two and
three reactors, citing the relatively low outside
temperatures of the containers.
In its report, Japan's government informs the IAEA that fuel
is assumed to have melted down and may have burnt through
the reactor pressure vessels of units one, two and three and
into their outer steel containment vessels.
Tokyo also pledged to reform its nuclear safety systems,
including by separating the watchdog NISA from the ministry
of economy, trade and industry, which promotes nuclear power
— echoing an IAEA recommendation.
In the report, Japan apologises to the international
community for the disaster, expressing its "remorse that
this accident has raised concerns around the world about the
safety of nuclear power generation."
Tuesday, a 10-member expert panel independent of the nuclear
industry met for the first time to look into the causes of
the world's worst atomic accident since Chernobyl, in
Ukraine, a quarter-century ago.
Panel leader Yotaro Hatamura, a Tokyo University professor
emeritus on the study of human error, said at the meeting
that "nuclear power has higher energy density and is
dangerous. It was a mistake to consider it safe."
Meanwhile, frantic efforts continued at the plant to meet
TEPCO's stated deadline of bringing all six reactors at
Fukushima Daiichi to a stable state of "cold shutdown" some
time between October and January.
hosing operations have left more than 100,000 tonnes of
highly radioactive water in buildings, basements and ditches
at the plant, and TEPCO is struggling to remove the runoff
so it can resume crucial repair work.
Contaminated water has spilled or been released several
times into the Pacific Ocean, and environmental group
Greenpeace has warned that it has found unsafe radiation
levels in marine species as far as 50 kilometres (30 miles)
been testing decontamination equipment, some provided by
U.S. and French companies, to remove radioactive substances,
oil and sea salt from the runoff water so it can be reused
as a reactor coolant from about mid-June. With the advent of
the summer rainy season, it has also started to ship to the
plant 370 truck-sized water tanks with a total capacity of
more than 40,000 tonnes to store excess contaminated water.