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updated: 1/30/2018 7:48 PM

Worst-hit reactor at Fukushima may be easiest to clean up

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  • In this Thursday, Jan. 25, 2018, photo, an installation of a dome-shaped rooftop cover housing key equipment is near completion at Unit 3 reactor of the Fukushima Dai-ich nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The final pieces of a jelly roll-shaped cover are being put in place atop Fukushima’s most damaged nuclear reactor. Huge cranes have been installed to begin removing 566 sets of still-radioactive fuel rods from a storage pool later this year. It’s taken seven years just to get this far, the first concrete step toward dismantling the Tokyo Electric Power Co. nuclear plant, damaged in an earthquake and tsunami.

    In this Thursday, Jan. 25, 2018, photo, an installation of a dome-shaped rooftop cover housing key equipment is near completion at Unit 3 reactor of the Fukushima Dai-ich nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The final pieces of a jelly roll-shaped cover are being put in place atop Fukushima’s most damaged nuclear reactor. Huge cranes have been installed to begin removing 566 sets of still-radioactive fuel rods from a storage pool later this year. It’s taken seven years just to get this far, the first concrete step toward dismantling the Tokyo Electric Power Co. nuclear plant, damaged in an earthquake and tsunami.
    Associated Press

  • In this Thursday, Jan. 25, 2018 photo, an installation of a dome-shaped rooftop cover housing key equipment is near completion at Unit 3 reactor of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018 photo, an installation of a dome-shaped rooftop cover housing key equipment is near completion at Unit 3 reactor of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • In this Thursday, Jan. 25, 2018, photo, Daisuke Hirose, an official at Tokyo Electric Power Co.'s decontamination and decommissioning unit, explains the progress at Unit 3, seen at left back, where a dome-shaped rooftop cover housing key equipment is near completion ahead of a fuel removal from its storage pool, a milestone in decades-long decommissioning at the Fukushima Dai-ichi nuclear power plant expected later this year in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018, photo, Daisuke Hirose, an official at Tokyo Electric Power Co.'s decontamination and decommissioning unit, explains the progress at Unit 3, seen at left back, where a dome-shaped rooftop cover housing key equipment is near completion ahead of a fuel removal from its storage pool, a milestone in decades-long decommissioning at the Fukushima Dai-ichi nuclear power plant expected later this year in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • In this Thursday, Jan. 25, 2018, photo, the "operating floor" atop Unit 3 shows two key remote-controlled equipment, a Toshiba fuel handling machine, far back, and a 10-meter (33-foot) -high crane, near side, used to remove spent fuel rods from the cooling pool -a key step before removing melted fuel from the primary containment chamber at the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018, photo, the "operating floor" atop Unit 3 shows two key remote-controlled equipment, a Toshiba fuel handling machine, far back, and a 10-meter (33-foot) -high crane, near side, used to remove spent fuel rods from the cooling pool -a key step before removing melted fuel from the primary containment chamber at the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • In this Thursday, Jan. 25, 2018, photo, a cooling pool where a total of mostly used 566 sets of fuel rods are stored underwater and covered by a protective net, waits to be removed in a step to empty the pool at Unit 3 of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima  plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018, photo, a cooling pool where a total of mostly used 566 sets of fuel rods are stored underwater and covered by a protective net, waits to be removed in a step to empty the pool at Unit 3 of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima  plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • In this Thursday, Jan. 25, 2018, photo, officials of Tokyo Electric Power Co., look into the fuel cooling pool, overlooked by a 8-meter (26-foot) -high, 74-ton fuel handling machine installed on the top floor at Unit 3 of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018, photo, officials of Tokyo Electric Power Co., look into the fuel cooling pool, overlooked by a 8-meter (26-foot) -high, 74-ton fuel handling machine installed on the top floor at Unit 3 of the Fukushima Dai-ichi nuclear power plant ahead of a fuel removal from its storage pool in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • This Thursday, Jan. 25, 2018, photo shows an external view of the reactor's dome-shaped rooftop cover housing key equipment near completion ahead of a fuel removal from its storage pool, a milestone in decades-long decommissioning at the Fukushima Dai-ichi nuclear power plant expected later this year at Unit 3 reactor in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima  plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    This Thursday, Jan. 25, 2018, photo shows an external view of the reactor's dome-shaped rooftop cover housing key equipment near completion ahead of a fuel removal from its storage pool, a milestone in decades-long decommissioning at the Fukushima Dai-ichi nuclear power plant expected later this year at Unit 3 reactor in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima  plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • In this Thursday, Jan. 25, 2018, photo, a plant official walks down the road outside Unit 2, left, one of the three melted reactors whose building escaped an explosion but ironically that has kept high radiation inside, falling behind other reactors in the cleanup process, which is expected to take decades at the Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.

    In this Thursday, Jan. 25, 2018, photo, a plant official walks down the road outside Unit 2, left, one of the three melted reactors whose building escaped an explosion but ironically that has kept high radiation inside, falling behind other reactors in the cleanup process, which is expected to take decades at the Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima Prefecture, northeast Japan, during an exclusive visit by The Associated Press. The hardest-hit reactor at the Fukushima plant in the March 2011 disaster is moving ahead of the other two melted reactors seven years later in what will be a decades-long cleanup.
    Associated Press

  • FILE - This combination of file photos shows the Unit 3 building of Tokyo Electric Power Co.'s Fukushima Dai-ichi nuclear power plant,, taken on Feb. 28, 2012, top, and on Aug. 2, 2017, bottom, in Okuma town in Fukushima prefecture, northeastern Japan. Despite scarce data from inside the reactors, the current roadmap says melted fuel removal methods will be finalized in 2019, with actual retrieval at one of the three reactors in 2021.

    FILE - This combination of file photos shows the Unit 3 building of Tokyo Electric Power Co.'s Fukushima Dai-ichi nuclear power plant,, taken on Feb. 28, 2012, top, and on Aug. 2, 2017, bottom, in Okuma town in Fukushima prefecture, northeastern Japan. Despite scarce data from inside the reactors, the current roadmap says melted fuel removal methods will be finalized in 2019, with actual retrieval at one of the three reactors in 2021.
    Associated Press

  • FILE - In this July 21, 2017, file photo, Tokyo Electric Power Co. (TEPCO) shows an image captured by an underwater robot inside the Unit 3 reactor at the Fukushima Dai-ichi nuclear power plant during a press conference at the TEPCO headquarters in Tokyo. Despite scarce data from inside the reactors, the current roadmap says melted fuel removal methods will be finalized in 2019, with actual retrieval at one of the three reactors in 2021.

    FILE - In this July 21, 2017, file photo, Tokyo Electric Power Co. (TEPCO) shows an image captured by an underwater robot inside the Unit 3 reactor at the Fukushima Dai-ichi nuclear power plant during a press conference at the TEPCO headquarters in Tokyo. Despite scarce data from inside the reactors, the current roadmap says melted fuel removal methods will be finalized in 2019, with actual retrieval at one of the three reactors in 2021.
    Associated Press

 
 

OKUMA, Japan -- High atop Fukushima's most damaged nuclear reactor, the final pieces of a jelly-roll shaped cover are being put in place to seal in highly radioactive dust.

Blown apart by a hydrogen explosion in 2011 after an earthquake and tsunami hit Japan's Fukushima Dai-ichi plant, reactor Unit 3 is undergoing painstaking construction ahead of a milestone that is the first step toward dismantling the plant.

The operating floor - from where new fuel rods used to be lowered into the core - has been rebuilt and if all goes as planned, huge cranes will begin removing 566 sets of still-radioactive fuel rods from a storage pool just below it later this year.

It has taken seven years just to get this far, but now the real work of cleaning up the Tokyo Electric Power Co. plant can begin.

"If you compare it with mountain climbing, we've only been preparing to climb. Now, we finally get to actually start climbing," said Daisuke Hirose, an official at the plant's decommissioning and decontamination unit.

Cleaning up the plant's three reactors that had at least partial meltdowns after the earthquake and tsunami is a monumental task expected to take three to four decades. Taking out the stored fuel rods is only a preliminary step and just removing the ones in Unit 3 is expected to take a year.

Still ahead is the uncharted challenge of removing an estimated 800 tons of melted fuel and debris inside the cracked containment chambers - six times that of the 1979 Three Mile Island accident.

The area in and outside of Unit 3 is part construction site and part disaster zone still requiring protection from radiation. A makeshift elevator, then a wind-swept outdoor staircase, takes visitors to the operating floor, more than 30 meters (100 feet) above ground.

Daylight streams in through the unfinished section of the new cover, a tunnel-like structure sealed at both ends to contain radiation. An overhead crane that moves on rails stands at the side of the storage pool, the maker's name, "Toshiba," emblazoned in large red letters.

The explosion left major chunks of debris that have been removed from the storage pool, a painstaking operation done using remote-controlled machinery and with utmost care to avoid damaging the fuel rods. Smaller rubble lines the pool's edge. The water's surface is obscured by a blue netting to prevent more debris from accidentally tumbling in.

The severe damage to Unit 3 has, in the end, made it easier to clean up than the other two reactors.

Under the latest government roadmap approved last September, removal of the fuel rods from units 1 and 2 was delayed by three years until 2023, a second postponement from the original 2015, because further decontamination and additional safety measures are needed.

Unit 1 fell behind because of a delay in removing debris and repairing key components on the operating floor. The Unit 2 building remained intact, keeping high radiation and humidity inside, which makes it more difficult for workers to approach and decontaminate.

Radioactivity on the Unit 3 operating floor has fallen to a level that allows workers in hazmat suits and filter-masks to stay up to two hours at a time, though most work still needs to be done remotely.

The segments of the new cover were pre-assembled and are being installed one by one by remote-controlled cranes. With two pieces left, the plant operator says the cover will be completed in February.

Removing the fuel rods in Unit 3 will be done with a fuel-handling crane. It will move the rods out of their storage racks and pack them in a protective canister underwater. A second Toshiba crane, a 10-meter (33-foot) -high yellow structure across the operating floor, will lift the canister out of the pool and load it onto a vehicle for transport to another storage pool at the plant.

Crane operators and others assigned to the project, which requires caution and skill, have been rehearsing the procedures.

The 1,573 sets of fuel rods stored in spent fuel pools at the three reactors are considered among the highest risks in the event of another major earthquake. Loss of water from sloshing, structural damage or a power outage could cause meltdowns and massive radiation leaks because the pools are uncovered.

Hirose said that starting fuel removal at Unit 3 would be "a major turning point."

Still, after the intact fuel rods are gone comes by far the most difficult part of decommissioning the plant: removing the melted fuel and debris from inside the reactors. Obtaining exact locations and other details of the melted fuel are crucial to determining the retrieval methods and developing the right kind of technology and robots. With most melted fuel believed to have fallen to the bottom, experts are proposing that it be accessed from the side of the containment vessel, not from the top as originally had been planned, based on the cleanup after an accident at the Three Mile Island nuclear plant in the United States.

Computer simulations and limited internal probes have shown that the melted fuel presumably poured out of the core, falling to the bottom of the primary containment vessels. Robotic probes at the Unit 3 and 2 reactors have captured images of large amounts of melted fuel, but attempts so far at Unit 1 have been unsuccessful.

Despite scarce data from inside the reactors, the roadmap says the methods for melted fuel removal are to be finalized in 2019, with actual retrieval at one of the three reactors in 2021. Hirose says it is premature to say whether Unit 3 will be the first.

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Follow Mari Yamaguchi on Twitter at twitter.com/mariyamaguchi

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