Scale of Fukushima clean-up revealed as decommissioning 'road map' is revised
Revision of the "road map" to decommission nuclear power plant destroyed by tsunami exposes the severity of challenges faced
PUBLISHED : Tuesday, 16 June, 2015, 1:29am
UPDATED : Tuesday, 16 June, 2015, 2:05am
Julian Ryall in Tokyo
A Tepco employee in protective gear at Fukushima.Photo: AP
Japan's decision to revise its "road map" for the decommissioning the Fukushima nuclear plant has raised new questions about the scale of the problems that remain to be overcome.
The decision delays the removal of spent fuel rods stored inside the severely contaminated reactor buildings by as much as three years.
It was announced on Friday, after discussions between the Japanese government and Tokyo Electric Power Co (Tepco), the operator of the plant, which was destroyed by a tsunami triggered by the March 2011 earthquake.
This marks the second revision of the road map after it was last revised in June 2013. The revised schedule is designed to ensure the safety of workers at the site, the government and Tepco claimed, rather than on completing the decommissioning work as soon as possible.
Nuclear industry analysts insist, however, that delays to the initial timeline were inevitable because engineers at the plant would be trying to solve problems that had never been encountered before.
"It was always felt that they were setting their deadlines too soon and that it would be difficult to keep to the schedule they were setting themselves," a nuclear industry insider said.
"It was more a case of the authorities being forced to set as short a schedule as possible to keep public criticism to a minimum. But that failed to take into account all the problems they were inevitably going to come up against and would affect that schedule.
"It was over-ambitious and more of a political decision than one truly taking into account the scale of the problems they face."
Among them are the recovery of fuel rods - some of which may be damaged - held in storage pools on the upper stories of the reactor buildings. Accessing the storage pools has proved to be a challenge due to damage to the structures and debris.
There are other long-term concerns over water that has been used to cool the reactor vessels but has become highly contaminated and now has to be stored at the site, as well as finding a place to store the radioactive waste once it is recovered.
The biggest challenge, however, is devising a safe way of removing the melted fuel from the reactors. Even now, more than four years after the disaster, nuclear engineers can only make educated guesses as to where the molten fuel has pooled and the state it is in.
Tepco and the government insist that the changes will not have an impact on dates that have been set for some of the major milestones in the work, including the final completion of the decommissioning process.
The process of removing the molten fuel from three reactors at the plant is still due to commence before 2021, while the disposal of contaminated water leaking into the reactor buildings should be completed by 2020. According to the government, the decommissioning process for the second-worst nuclear disaster in history should be completed by March 2051.
"Up until now, our schedule has been set with the focus on the measures that needed to be achieved," a spokesman for Tepso said. "But we found that this was putting too large a burden on the workers.
"It also meant that we had to change the schedule as problems cropped up."
The biggest hazard at the plant remains the high amounts of radiation within reactor buildings. Levels are too high for a human to survive more than two minutes, while attempts to use robots to survey the damage have foundered because they can't negotiate the debris.
Additional reporting by Reuters
