Japan is incapable of safely decommissioning the devastated Fukushima nuclear plant alone and must stitch together an international team for the massive undertaking, experts say, but has made only halting progress in that direction.
Unlike the United States and some European countries, Japan has never decommissioned a full-fledged reactor. Now it must do so at the Fukushima Dai-Ichi plant. Three of its six reactors melted down after the 2011 earthquake and tsunami, making what is ordinarily a challenging operation even more complex.
The cloud over Japan's capacity to get the decades-long job done has further undermined the image of the nuclear industry with the public.
Opinion surveys show a majority of Japanese are opposed to restarting 50 reactors that were put offline for safety and other checks in the aftermath of the disaster. Japan has been forced to import oil and gas to meet its power needs, burdening its already feeble economy.
"Even for the US nuclear industry, such a clean-up and decommissioning would be a great challenge," said Akira Tokuhiro, a professor of mechanical and nuclear engineering at the University of Idaho in the US who is among those calling for a larger international role at Fukushima.
Decommissioning a nuclear power plant normally involves first bringing the reactor cores to stable shutdown and then eventually removing them for long-term storage. It is a process that takes years. Throughout, radiation levels and worker exposure must be monitored.
At Fukushima, there is the daunting challenge of taking out cores that suffered meltdown, which is the most dangerous type of nuclear-power accident.
Their exact location within the reactor units is not known and needs to be ascertained so their condition can be analysed. That will require development of nimble robots capable of withstanding high radiation.
The lack of experts is worse at the regulatory level. The tally is zero. Japan's Nuclear Regulation Authority had no one devoted to decommissioning, said spokesman Juntaro Yamada, though it had experts dealing with the removal of fuel rods from one of the Fukushima reactor units.
Its predecessor organisation was criticised after the Fukushima disaster for being too close to the nuclear industry, so the members chosen for the new agency launched last year do not have direct ties to the industry, to ensure their objectivity.
The government-funded Nuclear Energy Safety Organisation, which is to be folded into the regulatory authority to beef up its expertise, has one expert on decommissioning, a person who studies overseas regulations on the process.
The group mainly helps with routine nuclear-plant inspections, but since the 2011 catastrophe has been involved with bringing the Fukushima plant under control.
In contrast, the US Nuclear Regulatory Commission has 10 people devoted to decommissioning. France has seven at the national level.
Tokuhiro, who has more than 20 years in the nuclear design and safety fields, is advocating the creation of an international team to help Japan, including those with experience at Three Mile Island in the United States and Chernobyl in Ukraine.