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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”

1

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