Two ways of presenting the same thing

June 12, 2015

Removal of spent nuclear fuel at Fukushima plant to be delayed

http://mainichi.jp/english/english/newsselect/news/20150612p2g00m0dm033000c.html

TOKYO (Kyodo) -- The government and Tokyo Electric Power Co. decided Friday to push back the start of used nuclear fuel removal from cooling pools at the crippled Fukushima Daiichi complex by a few years from the current schedule, with the decommissioning work proving to be highly difficult more than four years after the 2011 crisis.

Taking out fuel rod assemblies from the spent fuel pools inside reactor buildings is one of the key steps before extracting fuel debris from the Nos. 1 to 3 reactors that suffered core meltdowns. Despite the delay, the overall timeline for finishing the cleanup process of around 30 to 40 years remains intact, the government and TEPCO said.

According to the revised road map for decommissioning, removal work for the fuel assemblies from the No. 3 unit's cooling pool -- which is located above the damaged reactor -- will be delayed until fiscal 2017 from the first half of fiscal 2015.

Work to take out fuel assemblies from the Nos. 1 and 2 units' pools is now expected to begin in fiscal 2020, pushed back from the originally planned fiscal 2017.

Subsequent extraction of fuel debris -- the most challenging part of the decommissioning process -- is expected to start in 2021, but the government and the plant operator have yet to decide on detailed methods. They are seeking to decide on how to remove the fuel debris in fiscal 2018.

The latest road map also sets the goal of cutting the amount of underground water -- which is seeping into the plant and mixing with radioactive water generated in the process of cooling the damaged reactors -- to less than 100 tons per day in fiscal 2016 from the current 300 tons to address the toxic water buildup at the site.

It also said the government and TEPCO will begin discussions in the first half of 2016 on how to dispose of processed water that contains radioactive tritium -- currently deemed difficult to be removed due to the lack of practical technology.

The International Atomic Energy Agency and Japan's Nuclear Regulation Authority have suggested that such water be released into the ocean, rather than be kept in tanks, to enhance the safety of the plant, but TEPCO remains undecided on the issue given strong local opposition to dumping the water.

The government and TEPCO revised their road map for decommissioning the plant for the first time in two years, as the previous plan placed too much priority on speeding up decommissioning efforts, putting a heavy burden on workers exposed to the highly radioactive environment at the complex.

The road map was first crafted in December 2011 in the wake of a huge earthquake and tsunami in March of that year which triggered the world's worst nuclear crisis at the Fukushima plant since the 1986 Chernobyl disaster.

The major progress made so far in the unprecedented decommissioning process has been the removal of all fuel assemblies from a cooling pool of the No. 4 reactor. The No. 4 unit suffered a hydrogen explosion but avoided a reactor meltdown, unlike the Nos. 1 to 3 reactors.

Fuel removal delayed by up to 3 more years

http://www3.nhk.or.jp/nhkworld/english/news/nuclear.html

Jun. 12, 2015 - Updated 08:59 UTC+2

A new roadmap says the removal of fuel rods from the spent fuel pools of the crippled reactors at the Fukushima Daiichi plant will begin 2 to 3 years later than originally planned.

Officials from the Japanese government and Tokyo Electric Power Company officially endorsed the revised plan at a meeting on Friday.

The decommissioning schedule for the reactors disabled in the 2011 earthquake and tsunami was reviewed for the first time in 2 years.

The roadmap refers to 2 major tasks -- removal of the fuel rods left inside spent fuel pools in the reactor buildings and cleaning up the melted nuclear fuel in the reactors.

The revised plan says the removal of fuel rods from the pools may be postponed until 2017 at the No.3 reactor building -- a delay of 2 years. It says the work at the No.1 and No.2 reactor buildings will start in 2020 -- 3 years later than originally planned.

Officials cite the need for more time to remove radioactive debris from the buildings and decontaminate the facility.

The revised roadmap also calls for studying new ways of removing molten fuel from the reactors, in addition to the current procedures. The new methods will not utilize water to shield workers from the strong radiation.

The initial methods entailed filling the reactor containment vessels with water before removing the melted fuel.

But the officials found this to be more difficult than they originally thought due to the possibility of water leaks from the vessels as well as the need to ensure their earthquake resistance.

The new roadmap keeps the initial target of beginning the removal of melted nuclear fuel within 6 years, but the plan does not state which reactor will be chosen first.

Industry ministry officials say the start of the removal will depend on which method is selected, but they believe it can begin within 6 years.

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Roadmap keeps initial plan to remove melted fuel

http://www3.nhk.or.jp/nhkworld/english/news/20150612_13.html

Jun. 12, 2015 - Updated 04:59 UTC+2

The new roadmap for scrapping the crippled Fukushima Daiichi nuclear plant maintains the initial target of starting the most difficult work -- the removal of melted nuclear fuel from its reactors -- within 6 years.

But the plan still does not set a schedule for such things as which reactor will come first and when.

Officials from the Japanese government and Tokyo Electric Power Company officially endorsed the revised plan at a meeting on Friday.

The decommissioning plan for the reactors disabled in the 2011 earthquake and tsunami was revised for the first time in 2 years.

The plan now calls for studying new methods to remove the molten fuel in addition to the current methods. The new methods will not utilize water to shield workers from the strong radiation.

The initial methods entailed filling the reactor containment vessels with water before removing the melted fuel. But they found this to be more difficult than originally thought due to the possibility of water leaks from the vessels as well as the need to ensure their earthquake resistance.

In the roadmap, officials maintained the previous goal of starting to remove the melted fuel by 2021.

The roadmap also refers to plans to remove less damaged fuel rods from the plant's spent fuel pools. It says this work may be delayed by up to 3 years from the previous plan, citing the need to first remove debris from the buildings and decontaminate the facility.

Referring to the melted nuclear fuel, industry ministry officials say the start of the removal will depend on which method is chosen. Officials added that they believe this can be started within 6 years.