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REPUBLIC OF RWANDA
MINISTRY OF EDUCATION
INSTITUTE OF AGRICULTURE, TECHNOLOGY AND EDUCATION OF KIBUNGO (INATEK)
FACULITY OF RURAL DEVELOPMENT
DEPARTMENT OF AGRICULTARAL ENGINEERING
PRACTICE OF GEOMORPHOLOGY
Presented by:
1. Jean Paul HABIMANA (N˚7269 /11)2. Yvonne GAHAMANYI (N˚3882 /08)3. Forongo GATANAZI (N˚3999 /08)4. Betty GATESI (N˚4849 /08)5. Elie HABIMANA (N˚7852 /11) 6. Venant GATO (N˚1670 /08) 7. Thomas HABANABAKIZE (N˚3367 /07) 8. Celestin HABIYAREMYE (N˚4124 /08)
Lecturer: M.Sc. Siegfried MUSANGWA
KIBUNGO, May 2011
“RESEARCH ON FUKUSHIMA DAI-
ICHI”
“RESEARCH ON FUKUSHIMA DAI-
ICHI”
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RESEARCH ON FUKUSHIMA DAI-ICHI
1. INTRODUCTION
The Fukushima I Nuclear Power Plant (Fukushima I NPP), also
known as Fukushima Dai-ichi (dai-ichi means "number one"), is a disabled
nuclear power plant located on a 3.5 km2 site in the towns of Okuma and
Futaba in the Futaba District of Fukushima Prefecture, Japan. First
commissioned in 1971, the plant consists of six boiling water reactors (BWR).
These light water reactors drove electrical generators with a combined
power of 4.7 GWe, making Fukushima I one of the 15 largest nuclear power
stations in the world. Fukushima I was the first nuclear plant to be
constructed and run entirely by the Tokyo Electric Power Company (TEPCO).
The plant suffered major damage from the 9.0 earthquake and subsequent
tsunami that hit Japan on 11 March 2011 and is not expected to reopen. The
earthquake and tsunami disabled the reactor cooling systems, leading to
nuclear radiation leaks and triggering a 20 km evacuation zone surrounding
the plant.
The main objective of this research is to unable the fourth year Agricultural
Engineering students to understand the damage caused by earthquake
(vibration of earth produced by the rapid release of energy) which mostly
leads to catastrophic disaster Tsunami (seismic sea waves) in the most
coastal countries.
All the information about FUKUSHIMA I NPP has been documented through
the internet.
Specific Objectives
To reveal Fukushima I NPP back ground
To acquire information on 11 March 2011 Fukushima I NPP accident
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2. BACK GROUND INFORMATION
Figure1: Japan map
Figure2: Sketch of BWR
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Simplified cross-section sketch of a typical BWR Mark I containment, as used
in units 1 to 5. Key: DW, dry well enclosing reactor pressure vessel; WW,
Torus-shaped wetwell all around the base enclosing steam suppression pool.
Excess steam from the dry well enters the wetwell water pool via downcomer
pipes; SFP, spent fuel pool area; RPV, Reactor Pressure Vessel; SCSW,
Secondary Concrete Shield Wall.
The Fukushima I Nuclear Power Plant consists of six light water, boiling water
reactors (BWR) designed by General Electric driving electrical generators
with a combined power of 4.7 gigawatts. Unit 1 is a 439 MWe type (BWR3)
reactor constructed in July 1967. It commenced commercial electrical
production on 26 March 1971. It was designed for a peak ground
acceleration of 0.18 g (1.74 m/s2) and a response spectrum based on the
1952 Kern County earthquake. Units 2 and 3 are both 784 MWe type BWR-4
reactors, unit 2 commenced operating in July 1974 and unit 3 in March 1976.
The design basis for all units ranged from 0.42 g (4.12 m/s2) to 0.46 g
(4.52 m/s2). All units were inspected after the 1978 Miyagi earthquake when
the ground acceleration was 0.125 g (1.22 m/s2) for 30 seconds, but no
damage to the critical parts of the reactor was discovered.
From September 2010, unit 3 has been fueled by mixed-oxide (MOX) fuel.
Units 7 and 8 were planned to start construction both in April 2012 and April
2013 and to come into operation in October 2016 and 2017 respectively. The
project was formally canceled by TEPCO in April 2011 after outrage was
expressed by local authorities about the fact that they were still included in
the supply plan for 2011, released in March 2011, after the accidents. TEPCO
stated that the plan had been drafted before the accident, but the pressure
caused them to formally withdraw the plans.
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Unit Type
Start
construc
tion
First
criticalit
y
Commer
cial
operatio
n
Electr
ic
powe
r
Reacto
r
supplie
r
Architect
ure
Construct
ionFuel
Fukushi
ma I – 1
BWR-
3
July 25,
1967
October
10, 1970
March
26, 1971
460
MW
General
ElectricEbasco Kajima LEU
Fukushi
ma I – 2
BWR-
4
June 9,
1969
May 10,
1973
July 18,
1974
784
MW
General
ElectricEbasco Kajima LEU
Fukushi
ma I – 3
BWR-
4
December
28, 1970
Septemb
er 6,
1974
March
27, 1976
784
MWToshiba Toshiba Kajima
LEU/
MOX
Fukushi
ma I – 4
BWR-
4
February
12, 1973
January
28, 1978
October
12, 1978
784
MWHitachi Hitachi Kajima
Fukushi
ma I – 5
BWR-
4
May 22,
1972
August
26, 1977
April 18,
1978
784
MWToshiba Toshiba Kajima
Fukushi
ma I – 6
BWR-
5
October
26, 1973
March 9,
1979
October
24, 1979
1,100
MW
General
ElectricEbasco Kajima
Fukushi
ma I – 7
(planned
ABWRCanceled
04/2011
(As
originally
planned)
October
2016
1,380
MW
Cancelled
04/2011
Fukushi
ma I – 8
(planned
ABWRCancelled
04/2011
(As
originally
planned)
October
2017
1,380
MW
Cancelled
04/2011
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The Fukushima Daiichi site is divided into two reactor groups, the leftmost
group when viewing from the ocean contains units 4, 3, 2 and 1 going from
left to right. The rightmost group when viewing from the ocean contains the
newer units 5 and 6, respectively the positions from left to right. A set of
seawalls protrude into the ocean, where water intake is in the middle, and
discharged on either side.
Aerial view of the Fukushima I plant area in 1975, showing sea walls
and completed reactors
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3. 11 MARCH 2011 FUKUSHIMA I NPP ACCIDENT
The Fukushima I nuclear accidents are a series of ongoing equipment
failures and releases of radioactive materials at the Fukushima I Nuclear
Power Plant, following the 9.0 magnitude Tōhoku earthquake and tsunami on
11 March 2011. Experts consider it to be the second largest nuclear accident
after the Chernobyl disaster, but more complex as all reactors are involved.
At the time of the quake, reactor 4 had been de-fueled while 5 and 6 were in
cold shutdown for planned maintenance. The remaining reactors shut down
automatically after the earthquake, and emergency generators started up to
run the control electronics and water pumps needed to cool them. The plant
was protected by a seawall designed to withstand a 5.7 meters (19 ft)
tsunami, but not the 14-meters (46 ft) wave which arrived 15 minutes after
the earthquake. The entire plant was flooded; including low-lying generators
and electrical switchgear in reactor basements, and its connection to the
electrical grid was broken. All power for cooling was lost and reactors started
to overheat, despite shutdown, due to natural decay of the fission products
created before shutdown. The flooding and earthquake damage hindered
external assistance.
Evidence soon arose of partial core meltdown in reactors 1, 2, and 3;
hydrogen explosions destroyed the upper cladding of the buildings housing
reactors 1, 3, and 4; an explosion damaged the containment inside reactor 2;
and multiple fires broke out at reactor 4. In addition, spent fuel rods stored in
spent fuel pools of units 1–4 began to overheat as water levels in the pools
dropped. Fears of radiation leaks led to a 20-kilometre (12 mi) radius
evacuation around the plant while workers suffered radiation exposure and
were temporarily evacuated at various times. One generator at unit 6 was
restarted on 17 March allowing some cooling at units 5 and 6 which were
least damaged. Grid power was restored to parts of the plant from 20 March,
but machinery for reactors 1-4 damaged by floods, fires and explosions
remained inoperable. Japanese officials initially assessed the accident as
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level 4 on the International Nuclear Event Scale (INES) despite the views of
other international agencies that it should be higher.
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The INES level was raised successively to 5 and then the maximum 7.
Measurements taken by the Japanese science ministry and education
ministry in areas of northern Japan 30–50 km from the plant showed
radioactive caesium levels high enough to cause concern. Food grown in the
area was banned from sale. It was suggested that worldwide measurements
of iodine-131 and caesium-137 indicate that the releases from Fukushima
are of the same order of magnitude as the releases of those isotopes from
the Chernobyl disaster in 1986; Tokyo officials temporarily recommended
that tap water should not be used to prepare food for infants. Plutonium
contamination has been detected in the soil at two sites in the plant.
The International Atomic Energy Agency (IAEA) announced on 27 March that
workers hospitalized as a precaution on 25 March had been exposed to
between 2 and 6 Sv of radiation at their ankles when standing in water in
unit 3. The international reaction to the accidents was also concerned. The
Japanese government and TEPCO have been criticized for poor
communication with the public and improvised cleanup efforts. Experts have
said that a workforce in the hundreds or even thousands would take years or
decades to clean up the area. On 20 March, the Chief Cabinet Secretary
Yukio Edano announced that the plant would be decommissioned once the
crisis was over.
Fukushima I nuclear accidents
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Satellite image on 16 March of the four damaged reactor buildings
4. CONCLUSION
It has been found that the failure of the emergency electricity
generators and subsequent failure of the cooling systems of plants is the
most likely cause of 11 March 2011 Fukushima I Nuclear Power Plant
accident. Despite the high productivity of nuclear materials, their use is
therefore recommended at very low extent with special safety precautions so
that the risk of radioactivity to the living being should be minimized as much
as possible.
5. REFERENCES
1. "IAEA Update on Japan Earthquake" . Available:
http://www.iaea.org/newscenter/news/tsunamiupdate01.html.
2. "Japan raises nuclear crisis severity to highest level" . Reuters.
Available: http://www.reuters.com/article/2011/04/12/japan-severity-
idUSTKE00635720110412 .
3. "Explainer: What Went Wrong in Japan's Nuclear Reactors" .
IEEE Spectrum.
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Available: http://spectrum.ieee.org/tech-talk/energy/nuclear/explainer-
what-went-wrong-in-japans-nuclear-reactors
4. "Fukushima faced 14-metre tsunami" . World Nuclear News.
Available: http://www.world-nuclear-news.org/RS_Fukushima_faced_14-
metre_tsunami_2303113.html
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