Fukushima draws world's focus on power plants
By Dhaneshi YATAWARA
Japan continues to suffer from a chain of earthquakes since Great
East Japan Earthquake struck on March 11 caused by a 9.0-magnitude
undersea megathrust earthquake off the coast of Japan that occurred at
14:46 Japan Standard Time (05:46 Coordinated Universal Time). Subsequent
to a series of earthquakes since then, unfortunately another earthquake
of magnitude 5.8 hit central Japan on Saturday morning, according to the
US Geological Survey. Going by the data at the US Geological Survey the
quake struck Eastern Honshu at around 11:19 hours according to local
time at the epicentre. (0219 hours Coordinated Universal Time) at a
depth of 20.1 kilometres.
Serious

The
nuclear accident left many dead and the city of Prypiat
was evacuated across a radius of 48 kilometers. Prypiat is an
abandoned city in the 30 km exclusion zone around the closed
Chernobyl nuclear power plant. |
"Overall, the situation at the Fukushima Daiichi nuclear power plant
remains very serious but there are early signs of recovery in some
functions, such as electrical power and instrumentation", said the
International Atomic Energy Agency last Friday.
Coincidently on April 26 Belarus, Ukraine and Russia will mark the
25th anniversary of the nuclear reactor explosion in Chernobyl, the
place where the world's worst civil nuclear accident took place in 1986.
Fukushima Daiichi Nuclear Plant disaster joins the list as the second
same level member. The world witnessed the world's largest nuclear
disaster for the second time. Chernobyl reactor No. 4 exploded on April
26, 1986, contaminating a large part of Northern Europe, including
Belarus and Russia, with harmful radiations. Around 50,000 Pripyat
residents were evacuated. Even 25 years after the disaster they cannot
return yet.
The nuclear accident left many dead and the city of Prypiat was
evacuated across a radius of 48 kilometers. Prypiat is an abandoned city
in the 30 km (19 miles) exclusion zone around the closed Chernobyl
nuclear power plant. The plant is however, now opened to tourists. Only
"officially developed" and "medically safe" tour of the region is
recommended for any visitor.
According to the media statements given by the Japanese National
Police Agency as of April 14 the number of dead from the disaster stood
at 13,456. As of last Thursday (April 14) a total of 4,902 people had
been injured, and another 139,020 displaced by the disaster.
According to the Police Agency on Friday for the first time rescue
and search teams entered six kilometres close to the damaged Fukushima
Daiichi nuclear power plant to carry out their mission.
On April 12 the Japanese Nuclear and Industrial Safety Agency (NISA)
issued a new provisional rating for the accident at the Fukushima
Daiichi nuclear power plant assessing it as a Level 7 on the IAEA
International Nuclear and Radiological Event Scale (INES). The nuclear
accident at Fukushima Daiichi is now a "Major Accident" on INES. Level 7
is the most serious level on INES and is used to describe an event
comprised "A major release of radioactive material with widespread
health and environmental effects requiring implementation of planned and
extended countermeasures".
Earlier on March 18, Japanese authorities rated the core damage at
the Fukushima Daiichi 1, 2 and 3 reactor Units caused by loss of all
cooling function to have been at Level 5 on the INES scale. They further
assessed that the loss of cooling and water supplying functions in the
spent fuel pool of the Unit 4 reactor to have been rated at Level 3.
NISA estimates that the amount of radioactive material released to the
atmosphere is approximately 10 percent of the 1986 Chernobyl accident,
which is the only other nuclear accident to have been rated a Level 7
event. The INES was introduced in 1990 by the International Atomic
Energy Agency (IAEA) in order to enable prompt communication of safety
significance information in case of nuclear accidents.
As INES ratings are not assigned by a central body, high-profile
nuclear incidents are sometimes assigned INES ratings by the operator,
by the formal body of the country, but also by scientific institutes,
international authorities or other experts which may lead to confusion
as to the actual severity.
A number of criteria and indicators are defined to assure coherent
reporting of nuclear events by different official authorities.
There are 7 levels on the INES scale; 3 incident-levels and 4
accident-levels. There is also a level 0. The level on the scale is
determined by the highest of three scores: off-site effects, on-site
effects, and defence in depth degradation.
Earthquakes
As of April 15 records of US Geological Survey four earthquakes have
hit near the east coast of Honshu in Japan and three off the East Coast
of Honshu and another to Eastern Honshu. Japanese authorities may revise
the INES rating at the Fukushima Daiichi nuclear power plant as further
information becomes available. Japan's nuclear safety agency has told
plant operators to check and improve outside power links to avoid
earthquake-related outages similar to those causing the country's
current nuclear crisis.
On the latest updates from the operator company of Fukushima Daiichi,
Tokyo Electric Power Co., Inc (TEPCO) its President Masataka Shimizu has
said at a press conference held by the company on April 13 that he
wishes to step down from all his posts. Shimizu also serves as Vice
Chairman of the Nippon Keidanren with a membership of many leading
companies and Chairman of the Federation of Electric Power Companies of
Japan. TEPCO nuclear power plant to compensate tens of thousands of
households forced to evacuate due to radiation leaks. Evacuated people
who lived within 30 kilometers of the plant will be eligible for
provisional damages, which have been set at 1 million Yen per family and
750,000 Yen for single-persons.
Gamma dose in the air as a result of the radiation leak rates are
measured daily in all 47 prefectures of Japan. Perfectures are
administrative divisions of Japan. The values have tended to decrease
over time. For Fukushima, on April 14 a dose rate of 2.0 microsiverts
per hour ( µSv/h) was reported. In the Ibaraki prefecture, a gamma dose
rate of 0.14 µSv/h was reported.
The gamma dose rates in all other prefectures were below 0.1 µSv/h.
Dose rates are also reported specifically for the Eastern part of the
Fukushima prefecture, for distances beyond 30 km from Fukushima Daiichi.
On 14 April, the values in this area ranged from 0.1 to 21 µSv/h. The
desperate struggle to bring the defunct reactors under control continues
in Japan while the world watch the event every millisecond.
A new government panel plans to outline guidelines in July on
compensation for damage caused by radioactive substance leaks from the
Fukushima Daiichi power plant, its chairman Yoshihisa Noumi from
Gakushuin University has told the media on Saturday. Lessons learnt at
Fukishima will surely be a turning point in the world's history. |