Photo/Illutration Chubu Electric Power Co.’s Hamaoka nuclear power plant in Shizuoka Prefecture (Asahi Shimbun file photo)

Dismantling work has begun at Chubu Electric Power Co.’s Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture, the first time a commercial reactor in Japan is being dismantled.

On March 17, a crane was used to lift and remove the top lid of the No. 2 reactor pressure vessel, which contained nuclear fuel during its operation.

The start of the dismantling work signifies that the so-called “great era of decommissioning” has begun in earnest in Japan. 

The No. 1 and No. 2 reactors at the Hamaoka plant are both boiling water reactors.

The No. 1 reactor began operation in 1976 with an output of 540,000 kW, and the No. 2 reactor went online in 1978 with an output of 840,000 kW.

After the earthquake resistance guidelines for nuclear power plants were revised in 2006, Chubu Electric Power Co. decided to decommission both reactors in 2008 due to the high cost of seismic reinforcement and other necessary measures.

Work began in 2009.

So far, spent nuclear fuel in the building has been removed to the fuel pools of No. 4 and No. 5 reactors, which are located on the same site, and unused fuel has been taken off site.

Decontamination of equipment has been carried out, and since fiscal 2015, dismantling of the turbines, generators and part of the reactor building has also been under way.

The dismantling of the reactor, which began on March 17, is considered the main part of the decommissioning work.

The reactor pressure vessel and internal reactor structures have high radiation levels that make them inaccessible to humans.

The work will be carried out by remote control using specialized robots, which requires advanced technology.

Chubu Electric Power Co. will dismantle the No. 1 and No. 2 reactors over a period of about 12 years, starting with the No. 2 reactor first.

The decommissioning of the two reactors is expected to be completed in fiscal 2042 after the buildings are finally dismantled.

Chubu Electric estimates that the decommissioning of No. 1 reactor will cost about 37.9 billion yen ($254.4 million) and about 46.2 billion yen for the No. 2 reactor.

However, the company has not yet decided where to dispose of the large amount of metal, concrete and other waste materials generated by the decommissioning work.

In Japan, the Japan Atomic Energy Agency has decommissioned a small experimental reactor, but no commercial reactors have been decommissioned yet.

At present, 18 nuclear power plants, excluding Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, are scheduled to be decommissioned.

Many other reactors in Japan have been in operation for a long time.

While Japan has entered an era of decommissioning, decommissioning plans continue to be postponed due to the lack of a finalized waste disposal site.

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