Tokyo Electric Power Co. plans to decommission the damaged reactors at the wrecked Fukushima nuclear plant in 30 to 40 years, the Japanese government said, outlining a “roadmap” for dismantling the station.
The company known as Tepco will start removing the spent fuel rods at Fukushima Dai-Ichi within two years, according to the schedule released today in Tokyo. Engineers will attempt to start removing melted fuel from one of the reactors within a decade, the government said.
Three reactors went into meltdown after the March 11 earthquake and tsunami damaged the station, causing the worst nuclear crisis since Chernobyl in 1986. Decommissioning the station may cost at least 1.15 trillion yen ($14.8 billion), according to a government estimate in October.
Dismantling the reactors will probably be more complex than Chernobyl because it involves more nuclear fuel, said Najmedin Meshkati, a professor of civil engineering at the University of Southern California, who worked as a consultant on decommissioning the Ukraine station.
“It is difficult to get an accurate estimate now because we really don’t have a very good understanding of the level of devastation, the amount of the meltdown and the material that needs to be removed and the exact radiation level,” he said.
Tepco and the government may have to revise the timetable after robots are used to gather more details about the extent of the damage deep inside the reactors, Meshkati said.
To get to the spent fuel rods engineers must negotiate blown out walls and the twisted remains of steel infrastructure, after explosions tore reactor buildings apart in the early days of the crisis.
There are more than 2,700 spent fuel assemblies in four buildings, according to the Japan Atomic Industrial Forum. More than 1,300 are located in the No. 4 unit, which didn’t melt down because the fuel had been removed from the reactor for maintenance before the quake and tsunami struck.
Once the spent rods are removed, Tepco will start working on extracting the melted cores, which dropped to the bottom of the reactor vessels then burnt through inner steel casings into concrete foundations. The fuel didn’t breach a second steel containment barrier.
Reactor No. 1 had 400 fuel assemblies and reactors 2 and 3 had 548 each, according to the atomic forum.
Each assembly contains 60 uranium rods about 4.35 meters (14 feet) in length adding up to about 270 metric tons of fuel to be removed, said Tony Irwin, a former reactor manager for British Energy Group Plc who lectures on nuclear technology at the Australian National University.
Striking a Balance
Tepco is probably waiting for radiation levels to fall before attempting to extract the melted fuel, Irwin said.
“It’s a balance between the dose they’re going to get to workers doing this job and the need to remove the fuel from the reactor,” he said.
The government on Dec. 16 announced Tepco had brought the station into a state known as cold shutdown, meeting its target to stabilize the reactors by the end of the year and allowing it to move to the next phase of resolving the crisis.
Radiation fallout caused 160,000 people to flee areas around the Fukushima station, which is located about 220 kilometers (137 miles) north of Tokyo and has six reactors.
The cost of the cleanup and compensating residents and businesses affected by the catastrophe may bankrupt Tepco, which has asked the government for support and received emergency loans from its creditors.
Tepco shares fell to the lowest in two months today after the Yomiuri newspaper said the utility may be nationalized to avert collapse. The government may invest 1 trillion yen to acquire stock while banks may be asked to lend the same amount, the newspaper reported. Tepco shares fell 9.8 percent.
“We are considering all options,” Trade and Industry Minister Yukio Edano said today in Tokyo when asked about the Yomiuri report. He was speaking at a press conference to outline the decommissioning schedule.
Edano said the roadmap didn’t include decommissioning costs because “it’s difficult to make a firm estimate at the moment.”
The cost of the cleanup won’t be an impediment to carrying out the project, Goshi Hosono, the minister in charge of the response to the disaster, said today at the same briefing.
“There won’t be any delays in the decomissioning process due to the cost,” he said. “I ordered Tepco not to allow that to happen.”
The government will be sensitive to the aspirations of those displaced by the disaster, Edano said.