In this July 27, 2017 file photo, contaminated water storage tanks are seen on the Fukushima No. 1 nuclear plant grounds, in Okuma, Fukushima Prefecture. (Mainichi)

FUKUSHIMA -- At least four foreign technical intern trainees are working at the construction site on the premises of the crippled Fukushima No. 1 Nuclear Power Plant despite the policy of its operator, Tokyo Electric Power Co. (TEPCO), that bans the employment of such trainees there, the Mainichi has learned.

TEPCO has acknowledged to the Mainichi that the foreigners are indeed at work at the plant in Fukushima Prefecture. The plant has been shut down due to the core meltdown accidents at some of its nuclear reactors after the March 2011 earthquake and tsunami devastated northeastern Japan.

A TEPCO official said that the practice of letting the trainees work does not match the intentions of the Technical Intern Training System. "We will demand our contractors to thoroughly check the residency status (of their foreign workers). We will do our own checks too," the official said.

The Mainichi investigation has found that the four Vietnamese and other trainees are in their 20s or 30s and two of them just arrived in Japan last year and thus speak little Japanese. Two more foreign construction workers operate inside the grounds of the Fukushima plant.

The six workers, employed by a Tokyo-based subcontractor of a major construction company, are involved in laying the foundations of a new facility designed to burn rubble or trees with potential radioactive contamination. The work began in November last year.

According to TEPCO, the area the six workers are assigned to is outside the radiation controlled area where protection from radiation is necessary. Although they are inside the premises of the nuclear power plant, they did not receive training on how to protect themselves from radiation, and there is no need to control their radiation exposure, the company said.

The six workers are made to wear dosimeters but told the Mainichi that they were not aware of the amount of radiation they have received.

The Technical Intern Training System is designed to transfer technology to developing countries, but Vietnam does not have nuclear power plants where workers could be exposed to radiation. The Vietnamese government ended a plan to construct a nuclear power plant in 2016 due to a shortage of funds and out of consideration of public opposition following the nuclear disaster at the TEPCO plant in 2011.

TEPCO officials told a news conference in February 2017 that the company wanted to protect the working environment with its own control measures as the training system was designed for the trainees to acquire knowledge and experience in Japan and pass that on to people at home.

A TEPCO official told the Mainichi that the company does not accept technical intern trainees to work at locations even outside the radiation controlled areas, adding that the company intends to strengthen the contractual management of its contractors.

The president of the construction company that hires the six foreigners said that he was told by the main contractor to refrain from using foreign workers as much as possible. "But our industry cannot carry on without foreigners any longer," he said.

According to the Ministry of Land, Infrastructure, Transport and Tourism, some 55,000 foreigners were reported to have worked in the construction sector in 2017, more than four times the number recorded five years earlier. Out of the 2017 total, some 37,000 were technical intern trainees.

(Japanese original by Shunsuke Sekiya, Chiba Bureau)