HomenuclearNuclear Power Plant Accident

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Nuclear Power Plant Accident

Several years have passed since the Fukushima Daiichi nuclear power plant accident began, triggered by the East Japan Great Earthquake on 11 March 2011 and subsequent events. The negative effects of nuclear power generation are catastrophic even during decommissioning of the nuclear plant.

Onsite Challenges

In September 2017, the Japanese government revised the medium- and long-term roadmap for the decommissioning of the Fukushima Daiichi site. Key components of which are:

  • Spent Fuel Removal from the pools of units 1–3 has been delayed for between one and three years. New target dates for the start of the operation are mid-Financial Year (FY) 2018 for unit 3, and “around FY 2023” for units 1 and 2.
  • Fuel Debris Removal is still scheduled to begin in 2021 but the determination of the retrieval method has been delayed by one year to FY 2019. On 19 January 2018, fuel debris was identified through visual inspection by remote-controlled camera of the containment vessel of unit 2.

Contaminated Water Management

Large quantities of water—about 3 cubic meters per hour (m3/h) per reactor—are still continuously being injected to cool the fuel debris. The highly contaminated water runs out of the cracked containments into the basements, where it mixes with water that has penetrated the basements from an underground river.

The commissioning of a dedicated bypass system and the pumping of groundwater has reduced the influx of water from around 400 m3/day to about 140 m3/day. An equivalent amount of water is decontaminated, although it contains still very high levels of tritium (over 500,000 Bq/l), and stored in large tanks.

The storage capacity onsite has been increased to 1.1 million m3 and will be enlarged to 1.4 million m3 by 2020. A frozen soil wall that was designed to further reduce the influx of water was commissioned in 2016. Its effectiveness is limited, as water still enters the basements.

Worker Exposure

8,000 workers—almost 9 out of 10 are Tokyo Electric Power Company (TEPCO) subcontractors—are involved in decommissioning work.

The average doses to subcontractors are more than twice as high as for TEPCO workers. In December 2017, another worker’s leukemia—the third case—was recognized as an occupational disease caused by the nuclear power plant accident. A fourth case, that was recognized, involved thyroid cancer.

Offsite Challenges

Amongst the main offsite issues are the future of tens of thousands of evacuees, the assessment of health consequences of the disaster, the management of decontamination wastes and the costs involved.

  • Evacuees – According to government figures, the number of evacuees from nuclear power plant accident Prefecture as of February 2018 was about 19,500 (vs. 164,000 at the peak in June 2013). The government has lifted restriction orders for five impacted municipalities. However, according to a survey by the Reconstruction Agency, only 3–29% of the people returned, and 15–50% of the people already decided not to return to their homes (or what is left of them). Many remain undecided. In November 2017, the United Nations Human Rights Council (UNHRC) voiced concern about the Japanese government’s countermeasures for the evacuees.
  • Health Issues – Officially, as of the end of December 2017, a total of 197 people have been diagnosed with a malignant tumor or suspected of having a malignant tumor and 161 people underwent surgery. While the cause-effect relationship between the nuclear power plant accident related radiation exposure and illnesses has not been established, questions have been raised about the examination procedure itself and the processing of information.
  • Food Contamination – The highest level of contamination with 11,000 Bq/kg of Cesium (the limit is 100 Bq/kg) was found in wild-boar meat in December 2017. In total, 200 samples out of a total of 300,000 exceeded the limit.
  • Decontamination – Decontamination activities inside and outside the evacuation area in locations have already generated 16.5 million m3 of contaminated soil. Outside Fukushima Prefecture, contaminated soil is stored in more than 28,000 places (333,000 m3 in total). The Japanese Government claims that, by March 2018 in Fukushima Prefecture and other affected prefectures decontamination work had been completed where contamination was high (except for the difficult-to-return zones).

Cost of the Accidents

The Japanese Government has not provided a comprehensive estimate for the total cost of the accidents. However, according to the Ministry of Environment, up to FY2017, US$26.6 billion had been allocated to decontamination. TEPCO estimates that an additional US$6.4 billion will be needed for further decontamination from FY2018‑20.

According to the latest estimate, TEPCO was expected to borrow about US$119 billion, from the Government for nuclear power plant accident related expenditures. Go Solar!