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Nuclear Reactor Accidents - Halil Öztürk

The word “nuclear” can be used in different meanings in English, for example, to describe something relating to the nucleus of an atom in physics or to describe a type of family in daily life. No matter the context of the word, we can observe that people become cautious when they hear the word. To see the reason, commonly, some accidents in the past are the answer. At this point, it ought to note that we shall discuss neither the necessity nor the dangers of nuclear reactors in this paper, but try to summarise some well-known accidents in the history of nuclear reactors. Having mentioned the accidents, it is worth introducing the International Nuclear and Radiological Event Scale by International Atomic Energy Agency (INES). INES is a tool for communicating the safety significance of nuclear and radiological events to the public, consisting of 7 levels, each of which is important.

Figure 1: International Nuclear and Radiological Event Scale

Source: IAEA

Throughout this paper, there are some accidents from the most dangerous 3 levels, 5-6-7, including the Chernobyl disaster, Fukushima Daiichi nuclear disaster, and Three Mile Island accident.

As summarising the incidents of the 5th-6th-7th level, to be more obvious and direct, we will go with subheadings:

Chernobyl Disaster

Date/Location: April 26, 1986 / Pripyat-Ukraine-the Soviet Union

INES Level: 7

Human Health: According to the predictions of the UN, about 4,000 people died due to the disaster, and in total, about 600,000 people were subjected to a high dose of radiation, having caused radiation-induced cancer and leukemia.

Reason: A flawed reactor, No.4 reactor, design operated with inadequately trained personnel.

Total Production: The plant consisted of 4 RBMK-1000 reactors; the total energy production was 3,200 x 4 = 12,800 MWt (megawatt thermal).

Comments: Due to its great impact and usages in popular culture, such as TV series, journals, etc., about the disaster, it is probably by far the most frightening example people think when they hear something about nuclear. For OECD-Nuclear Energy Agency, the accident is owing to the lack of "safety culture," which is also highlighted by the World Nuclear Association. It is not the reactor itself that caused such an incident, but how safe it was kept.

Some Facts:

-The Chornobyl Nuclear Power Plant continued to generate electricity till December 15, 2000, when it was finally stopped.

-Today, the zone is visited by tourists with a “protective” route.

-Because the city of Pripyat had been abandoned, different wild animals have populated the city.

Fukushima Daiichi Nuclear Disaster

Date/Location: March 11, 2011 / Ōkuma, Fukushima-Japan

INES Level: 7

Human Health: 1 death was announced by the Japanese government; according to the UN, there had been no adverse, direct health effect among Fukushima prefecture residents. It is still an ongoing discussion.

Reason: 9.0 (9.1) magnitude earthquake triggering a tsunami. Also, 'tis still said that better preparation could have made a big difference, pointing out the human factor.

Total Production: The plant has six boiling water reactors, which together have a power generation capacity of 4.60 GW.

Comments: Because of its recent occurrence, it 'tis possible to see reports news about the incident, still. For Britannica, it is the second-worst nuclear accident in the history of nuclear power generation. Also, an independent investigation set up by Japan’s parliament concluded that it was a profoundly man-made disaster”.

Some Facts:

- Authorities are still working to clean up the area.

- All four Fukushima Daiichi reactors were written off due to damage in the accident.

- The negative image surrounding food produced in Japan has heavily impacted the Japanese economy and local producers who still find it difficult to make a living from their production, which nevertheless fully complies with consumption standards.

Three Mile Island Accident

Date/Location: March 28, 1979 / Pennsylvania, United States

INES Level: 5

Human Health: Hitherto, There have been no injuries or adverse health effects from the Three Mile Island accident.

Reason: Mistakenly close of an automatically operated valve in the Unit 2 reactor, shutting off the water supply to the main feedwater system.

Total Production: TMI-2, the reactors accident, was 906 MWe (net: 880).

Comments: Based upon Britannica, it was the most serious in the American nuclear power industry history. According to the United States Nuclear Regulatory Commission, a combination of equipment malfunctions, design-related problems, and worker errors led to TMI-2's partial meltdown and very small off-site releases of radioactivity.

Some Facts:

-TMI-1 had continued to generate electricity till September 20, 2019, despite the accident in TMI-2.

-The clean-up effort cost about 1 billion dollars.

All in all, in this paper, we have tried to show and summarise some historical nuclear reactor incidents to inform by categorizing some dimensions of them.