Japan's nuclear regulator has decided that it will order nuclear power plants to suspend operations if their new mandatory anti-terror facilities are not completed and have not passed inspections one week before the deadline.
The decision could lead to reactors in Japan that are currently online facing orders to shut down.
The Nuclear Regulation Authority decided in April that operations at the country's reactors would be suspended if anti-terror facilities are not completed within five years of the reactors clearing the requirements to go back online.
The facilities must include a standby control room and power sources to remotely cool reactors in the event of a terror attack or other emergencies.
On Wednesday, the authority decided on a process to halt reactors that fail to meet deadlines. It said that if the anti-terror facilities have not passed screenings by about six weeks before the deadline, plant operators will be given a chance to explain the delay.
If the operators fail to convince the authority, they will be ordered to halt their reactors about a week before the deadline.
Operators of 13 reactors at seven nuclear power plants nationwide have said they will not be able to keep the deadlines, or that they do not know when they will be able to pass inspections.
Among those 13 reactors, nine situated across five plants were approved to go back online. They include two reactors at the Sendai plant in Kagosihma Prefecture, which will face the earliest deadline in March of next year.
The authority is likely to order all nine of the reactors suspended if they fail to pass inspections by the deadlines.