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Spent Nuclear Fuel Removal at Fukushima Plant Delayed Again

Japan muddles on with Fukushima’s melted and “spent” fuel. The three year delay for emptying the reactors “spent” irradiated nuclear fuel into a dry cask storage runs the risk of another major earthquake causing a loss of cooling in the pools without containments and another major release of radiation. Plans for removing the melted reactor cores from Units 1, 2 and 3 still defied by inability to locate it.

 

sept 26 2017 fuel removal delayed.png

Fukushima Nuclear Plant Scrapping Plan Faces Another Delay

A key decision in decommissioning the crippled Fukushima Daiichi nuclear plant is being delayed. The Japanese government and operator made the announcement on Tuesday while giving an update on the roadmap for scrapping the plant.

In their first such update in 2 years, officials said they will postpone their decision on the method for removing molten fuel debris by one year, until fiscal 2019.

Experts believe that when the plant went into triple meltdown in 2011, most of the fuel inside the reactors collected at the bottom of containment vessels. They still don’t know the exact location, but possible molten fuel debris was caught on camera in July. The removal of this debris is considered the most challenging part of the plant’s decommissioning.

Originally, officials considered filling the containment vessels with water to block radiation while removing the debris. But now, they say they’re leaning towards a method called dry removal.

Experts say that method comes with safety challenges. “Because the containment vessel will not be filled with water, there is a possibility that radioactive substances may leak and get dispersed,” says Hosei University Visiting Professor Hiroshi Miyano.

Officials also gave an update on plans for the removal of spent nuclear fuel rods in 2 of the plants reactors. The rods are in storage pools and won’t be removed until fiscal 2023. That’s 3 years later than planned. The official timeline for scrapping the plant remains the same — about 30 to 40 years in total.

https://www3.nhk.or.jp/nhkworld/nhknewsline/nuclearwatch/fukushimanuclearplantscrapping/

Spent nuclear fuel removal at Fukushima plant pushed back again

n-roadmap-a-20170927-870x438Cabinet ministers attend a meeting at the Prime Minister’s Office on Tuesday to discuss a delay in the road map for decommissioning the Fukushima No. 1 nuclear power plant.

 

The government and Tokyo Electric Power Company Holdings Inc. decided Tuesday to further delay the removal of spent nuclear fuel left near two of the three reactors that suffered meltdowns at the Fukushima No. 1 nuclear plant.

In the road map for decommissioning the plant, revised for the fourth time since it was first crafted in 2011, highly radioactive spent fuel will be extracted from the cooling pools of reactors 1 and 2 starting in fiscal 2023 instead of fiscal 2020.

The decision marks the third delay for the removal plan, with the last adjustment coming in June 2015. The government said new technical issues and the need to take safety precautions led to the latest change.

The cleanup process is set to be completed in around 30 to 40 years.

Spent fuel removal at the plant’s reactor 3 will go ahead in fiscal 2018 as planned, having already been pushed back earlier this year.

In the decommissioning process, the removal of fuel rod assemblies from the spent fuel pools in reactor buildings is one of the key steps before extracting melted fuel debris. Reactors 1, 2 and 3 suffered core meltdowns following the March 2011 earthquake and tsunami disaster.

The removal of melted fuel debris has also been delayed, with an extraction plan set to be decided in fiscal 2019, pushed back from the first half of fiscal 2018.

Despite the delay in finalizing specific methods, the road map maintains a 2021 start for debris extraction, the most challenging part of the decommissioning process.

A method currently considered feasible by the government involves removing debris from the sides of the reactors after partially filling them with water.

The road map newly sets the goal of cutting the amount of underground water at the plant to address contaminated water buildup. Underground water — which gets mixed with accumulated radioactive water generated in the process of cooling the damaged reactors — is to be cut to around 150 tons per day in 2020 from the current 200 tons.

The road map does not mention a specific schedule for the disposal of processed water that still contains radioactive tritium.

The plan was first crafted in December 2011 in the wake of the meltdowns, the world’s worst nuclear crisis since the 1986 Chernobyl disaster.

Attempts have been made to confirm the situation inside the damaged reactors using specialized robots. A survey in July this year captured for the first time images of what is likely to be melted nuclear fuel at the bottom of reactor 3.

Isamu Kaneda, deputy mayor of the Fukushima Prefecture town of Futaba, expressed regret over the delay.

The town’s rebuilding depends on the development of decommissioning. It’s unfortunate,” Kaneda said. “But at the same time, the decommissioning process is an unprecedented project. It needs to be conducted carefully, so we can’t just ask them to speed it up.”

https://www.japantimes.co.jp/news/2017/09/26/national/spent-nuclear-fuel-removal-fukushima-plant-pushed-back/#.WcqxGxdx3rc

Spent nuclear fuel removal at Fukushima plant to be delayed again

Screenshot from 2017-09-27 00-36-28.png

 

TOKYO (Kyodo) — The government and Tokyo Electric Power Company Holdings Inc. decided Tuesday to delay again the start of removing spent nuclear fuel left near two of the three reactors which suffered a meltdown at the Fukushima complex.

In the road map for decommissioning the Fukushima Daiichi plant, revised for the fourth time since it was first crafted in December 2011, highly radioactive spent nuclear fuel will be extracted from the Nos. 1 and 2 units’ cooling pools starting in fiscal 2023 instead of fiscal 2020.

It is the third time that the schedule for spent fuel removal has been pushed back at the Nos. 1 and 2 reactors, with the previous postponement taking place in June 2015. The government said new technical issues and the need to take safety precautions led to the latest schedule change.

The cleanup process is to be completed in around 30 to 40 years.

For the No. 3 reactor at the Fukushima plant, the schedule to remove spent nuclear fuel during fiscal 2018 is unchanged after having already been pushed back earlier this year.

In the decommissioning process, taking out fuel rod assemblies from the spent fuel pools inside reactor buildings is one of the key steps before extracting melted fuel debris from the Nos. 1 to 3 reactors, all of which suffered core meltdowns following the March 2011 earthquake and tsunami disaster.

The schedule for extraction of the melted fuel debris at the reactors was also revised, with the determination of a specific approach to remove the debris to be made in fiscal 2019, rather than in the originally planned first half of fiscal 2018.

Despite the delay in finalizing specific methods, the road map kept the start of the debris extraction, the most challenging part of the decommissioning process, at 2021.

A method currently considered feasible by the government is debris removal from the side of the three crippled reactors by partially filling them with water.

The road map newly sets the goal of cutting the amount of underground water at the plant to address contaminated water buildup at the site. Underground water, which gets mixed with accumulated radioactive water generated in the process of cooling the damaged reactors — is to be cut to around 150 tons per day in 2020 from the current 200 tons.

It did not mention a specific schedule for disposal of processed water that still contains radioactive tritium.

The road map was first crafted in December 2011 in the wake of the 2011 disaster which triggered at the Fukushima plant the world’s worst nuclear crisis since the 1986 Chernobyl disaster.

Attempts have been made to confirm internal conditions of the damaged reactors using robots. A survey robot captured images of what is likely to be melted nuclear fuel at the bottom of the No. 3 reactor for the first time in July this year.

http://mainichi.jp/english/articles/20170926/p2g/00m/0dm/064000c

 

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September 26, 2017 - Posted by | Fukushima 2017 | , ,

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