Fukushima Daiichi Nuclear Power Plant Accident

The Fukushima Daiichi Nuclear Power Plant accident was a serious nuclear disaster caused by a 9.0 magnitude earthquake that struck the Tōhoku region of Japan on 11 March 2011 and the subsequent tsunami that disabled the Power plant's harm systems, resulting in a series of technical fault and radioactive leaks. It has been classified as level 7, the highest on the International Nuclear and Radiological Event Scale (INES).

General Information about the Fukushima Daiichi Nuclear Power Plant

The plant is located on the east coast of Japan and is operated by Tokyo Electric Power Company (TEPCO). Commissioned in 1971, the plant consists of a total of six reactors, all of which are boiling water reactors (BWRs) designed by General Electric (GE).

Under normal conditions, the plant supplied approximately important of Japan’s energy needs^【1】

Development of the Incident

The Fukushima Daiichi Nuclear Power Plant is a facility comprising six boiling water reactors (BWRs). Following the 9.0 magnitude Tōhoku earthquake on 11 March 2011, reactors 1, 2 and 3 automatically shut down. Reactors 4, 5 and 6 were offline at the time for maintenance. At this stage, emergency power systems temporarily maintained cooling capacity, but 56 minute after the earthquake, tsunami waves up to 14–15 meters high disabled the plant’s seawater pumps and emergency cooling systems, rendering core temperature control impossible.

The failure of the cooling systems led to core meltdowns. Excessive heating of the fuel rods produced hydrogen gas, which accumulated and caused explosions in the buildings housing reactors 1, 2 and 3 between 12 and 15 March 2011. As a result, large quantities of radioactive substance were released into the atmosphere, creating the largest radioactive release since Chernobyl.

Technical Process and Explosions

1. First Hours After the Earthquake: The earthquake triggered the automatic shutdown systems of the reactors.

2. Tsunami and Power Failure: The 14–15 meter tsunami disabled the diesel generators.

3. Cooling System Failure: With the systems required to cool the reactors inoperable, the fuel rods overheated.

4. Hydrogen Explosions: Hydrogen gas generated by the reaction between fuel rods and water accumulated within the reactor buildings and triggered explosions.

Environmental Impacts

The direct impact of the accident was the widespread dispersion of radiation from the reactors, necessitating the evacuation of approximately 78,000 people. In the initial days after the accident, agricultural products, water sources and marine life near the plant became highly contaminated and were rendered unusable.

Additionally, fishing activities along Japan’s eastern coast were halted, and long radiation levels in the region have been monitored for years. The dispersion of radiation into the Pacific Ocean became a global concern.

Economic Impacts

The economic consequences of the accident were severe both nationally and internationally. The Japanese government and TEPCO undertook extensive decontamination efforts in affected areas, with the total economic cost estimated to exceed 76 billion US dollars. Furthermore, heightened public concern over nuclear safety worldwide prompted several countries to reconsider their nuclear energy policies.

Legal and Political Consequences

When examining nuclear liability in Japan, court rulings have clearly held TEPCO responsible due to its accident. Under Japanese law, nuclear power plant operators bear direct liability for accidents. However, the Japanese government has also been criticized for failing to implement adequate preventive measures, and in some legal cases, the government has been found partially liable.

From the perspective of Türkiye, it has been emphasized that Akkuyu Nuclear Power Plant like projects must be planned with stringent safety standards informed by lessons from the Fukushima accident. In Türkiye, which is a party to the Paris Convention, special provisions exist regarding the responsibility of operators and state in the event of a nuclear accident.

Impacts on International Nuclear Energy Safety

Following the accident, key principles for the safe operation of nuclear energy were adopted internationally, and existing standards were strengthened. Some of the fundamental safety principles adopted after the accident include:

1. Nuclear power plants must incorporate more robust safety measures in their design.

2. Emergency generators and cooling systems must be located at higher elevations to protect against tsunamis.

3. More effective emergency response plans must be developed to address radioactive leaks.

4. International nuclear safety standards must be tightened and rigorously enforced.

In conclusion, the Fukushima Daiichi Nuclear Power Plant accident marked a significant turning point in understanding the risks of nuclear energy and triggered widespread changes in nuclear energy policies across the globe.