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Ikata nuclear reactor to be shut down – 40 year decommissioning process

Regulator approves Ikata 2 decommissioning plan

Japan’s Nuclear Regulation Authority (NRA) today approved Shikoku Electric Power Company’s decommissioning plan for unit 2 of its Ikata nuclear power plant in Ehime prefecture. Decommissioning of the unit is expected to be completed by 2059.

The three-unit Ikata plant

07 October 2020

Ikata 2 is a 538 MWe pressurised water reactor that began operating in March 1988. It was taken offline in January 2012 for periodic inspections. Shikoku announced in March 2018 that it did not plan to restart the reactor. It said the cost and scale of modifications required to upgrade the 40-year-old unit to meet the country’s revised safety standards made it uneconomical to restart it.

The utility submitted an outline of its plans for decommissioning the unit to the NRA on 10 October, 2018. Shikoku also submitted requests to Ehime prefecture and the municipality of Ikata, as specified under nuclear safety agreements concluded with those authorities.

Following a review, which included a total of seven public meetings, the NRA has today approved the decommissioning plan for Ikata 2.

According to the plan, decommissioning of the unit will take about 40 years and will be carried out in four stages. The first stage, lasting about 10 years, will involve preparing the reactor for dismantling (including the removal of all fuel and surveying radioactive contamination), while the second, lasting 15 years, will be to dismantle peripheral equipment from the reactor and other major equipment. The third stage, taking about eight years, will involve the demolition of the reactor itself, while the fourth stage, taking about seven years, will see the demolition of all remaining buildings and the release of land for other uses.

During the first stage, all fuel is to be removed from the unit. This includes 316 used fuel assemblies that will be sent for reprocessing and 102 fresh fuel assemblies that will be returned to the fuel fabricator.

“In the future, we will obtain the consent of Ikata Town and Ehime Prefecture, based on the safety agreement,” Shikoku said.

Shikoku decided in March 2016 to decommission unit 1 of the Ikata plant, also a 538 MWe PWR, which began commercial operation in September 1977. That unit had been taken offline in September 2011 for periodic inspections. Upgrades costing more than JPY170 billion (USD1.5 billion) would have been needed at the unit in order for it to operate beyond 40 years. The NRA approved Shikoku’s decommissioning plan for Ikata 1 in June 2017. That plan also sees the unit being decommissioned in four stages over a 40-year period.

The utility said, “As with unit 1, we will steadily proceed with the decommissioning of unit 2 with the highest priority given to ensuring safety.”

https://www.world-nuclear-news.org/Articles/Regulator-approves-Ikata-2-decommissioning-plan

October 12, 2020 Posted by | Japan | , , | Leave a comment

Rods can be removed from No. 2 reactor at Fukushima plant, Tepco says

”R—¿ã‚ðˆÚ“®‚·‚郍ƒ{ƒbƒgA remotely operated underwater robot casts light over nuclear fuel rods inside the fuel pool of the No.2 reactor at the Fukushima No. 1 nuclear power plant.

Jun 11, 2020

Fukushima – Tokyo Electric Power Company Holdings Inc. (Tepco) found no obstacles Wednesday to its planned removal of radioactive fuel rods from a spent fuel pool at the Fukushima No.1 nuclear power plant, the firm has said.

Tepco confirmed the findings after starting its first internal probe of the No. 2 reactor since the 2011 disaster. The investigation is expected to continue through Friday.

Using a remotely operated underwater robot to photograph the interior of the pool, submerged fuel rods and their storage racks were checked for any damage. A total of 615 spent and unspent fuel rods are stored in the pool.

White sediment was discovered on the aluminum alloy racks. It is believed to have formed from a reaction between aluminum and elements in sea water, which was injected into the pool to cool the nuclear fuel during the disaster.

Similar sediment was found in the reactor pools at units No. 3 and No. 4, from which fuel rods have already been removed, but according to Tepco it did not affect the process.

Similar to the No. 1 and No. 3 reactors, the No. 2 reactor suffered a core meltdown after it temporarily lost its cooling function in its spent fuel pool, but there was no hydrogen explosion at the building.

Because of that, the pool is thought to be free of debris and in a relatively stable condition.

High radiation levels on the top floor of the reactor building, where the fuel rods are located, have delayed cleanup efforts.

But progress in decontamination efforts has now enabled remote inspections to be carried out.

A new facility complete with a crane and equipment to lift out the fuel rods will be built on the south side of the No. 2 nuclear reactor building. The removal process is slated to begin sometime between fiscal 2024 and 2026.

https://www.japantimes.co.jp/news/2020/06/11/national/fuel-rods-fukushima-no-2/#.XuJIOufgqUk

June 22, 2020 Posted by | Fukushima 2020 | , , | Leave a comment

Tepco completes survey of Fukushima Daiichi 2 fuel pool

FD-2-used-fuel-pool-survey-June-2020-(Tepco)_1The ROV surveys the used fuel pool of Fukushima Daiichi unit 2 (Image: Tepco)

11 June 2020

There are no obstacles to the removal of assemblies from the used fuel storage pool of unit 2 at the damaged Fukushima Daiichi nuclear power plant, Tokyo Electric Power Company (Tepco) said today after completing an initial survey of the pool. Removal of the assemblies is scheduled to begin fiscal year 2024.

Similar to the reactors at units 1 and 3, unit 2’s reactor suffered a core meltdown after it temporarily lost its cooling functions, but the reactor building – which also houses the fuel storage pool – was spared a hydrogen explosion.

Using a submersible remotely-operated vehicle to investigate the fuel pool, Tepco concluded there was no damage to the fuel assemblies or the storage rack they are held in. It did, however, discover sand-like sediment at the bottom of the pool.

The utility said images captured during the pool’s survey will be used for designing equipment to be used in the removal of the fuel assemblies. It plans to start removing the 587 fuel assemblies from the unit’s used fuel pool between fiscal year 2024 (ending March 2025) and fiscal year 2026 (ending March 2027).

Dose levels on the operating floor of unit 2 are high, thereby making it difficult to access. Tepco has, however, already made progress with the clean-up of equipment, etc. that remains on the operating floor, providing access to the area near the storage pool.

It plans to complete the removal of all fuel assemblies from Fukushima Daiichi units 1-6 during 2031.

https://www.world-nuclear-news.org/Articles/Tepco-completes-survey-of-Fukushima-Daiichi-2-fuel

 

June 22, 2020 Posted by | Fukushima 2020 | , , | Leave a comment

Tepco prepares to survey Fukushima Daiichi unit 2 fuel pool

ROV-operation-training-May-2020-(Tepco)A worker receives training on using the submersible ROV

14 May 2020

Tokyo Electric Power Company (Tepco) has carried out training in the operation of a submersible remotely operated vehicle (ROV) that will be used to investigate the used fuel pool of unit 2 at the damaged Fukushima Daiichi nuclear power plant. The investigation is scheduled to begin in mid-June.

The company said it plans to start removing the 587 fuel assemblies from the unit’s used fuel pool between fiscal year 2024 (ending March 2025) and fiscal year 2026 (ending March 2027). “However, prior to commencing fuel removal, we must first ascertain whether or not there are any obstructions above the fuel or inside the cask pit, and we must also ascertain the condition of the skimmer surge tank,” Tepco said.

Dose levels on the operating floor of unit 2 are high thereby making it difficult to access, Tepco noted. It has yet to conduct an internal investigation of the unit’s used fuel pool, but it has made progress with the cleanup of equipment, etc. that remains on the operating floor and it is now possible to access the area near the storage pool. Tepco has also now deemed it possible to safely install investigation equipment.

Tepco held training sessions at the Fukushima robot test field in Minami-Soma City for eight employees between 13 and 15 May on operation of the submersible ROV. It says the design of equipment for the removal of the fuel from unit 2’s storage pool will be reviewed according to the results of the investigation.

https://world-nuclear-news.org/Articles/Tepco-readies-to-survey-Fukushima-Daiichi-unit-2-f

 

June 11, 2020 Posted by | Fukushima 2020 | , , | Leave a comment

Onagawa 2 upgrade faces further delay

Onagawa-NPP-(Kurihalant-Co-Ltd)

 

04 May 2020

The completion of safety countermeasures at unit 2 of the Onagawa nuclear power plant in Miyagi Prefecture, in Japan, will not be completed until March 2023, two years later than previously scheduled, Tohoku Electric Power Company announced on 30 April. Japan’s nuclear regulator concluded in February the unit meets revised safety standards, clearing the way for it to resume operation.

Tohoku expects to spend about JPY340 billion (USD3.2 billion) on the countermeasures, which include seismic reinforcement of Onagawa 2 and construction of a 29-metre high and 800m long sea wall to protect the plant from tsunamis. The company had originally planned to complete this construction work by April 2017, but the schedule has been pushed back a number of times. The latest plan had been for the countermeasures to be in place by the end of financial year 2020 (ending March 2021).

However, Tokohu has now announced it has reviewed its upgrade works plan for Onagawa 2’s operation. Based on discussions it has had with the Nuclear Regulation Authority (NRA), Tohoku has decided to expand or revise its construction works for improving the facilities at the plant. As a result, the entire plan of construction work has been delayed and is now expected to be completed in FY2022 (ending March 2023).

Tohoku applied to the NRA in December 2013 for a safety assessment of Onagawa 2 – a 796 MWe boiling water reactor (BWR) – to verify countermeasures applied at the plant meet new safety standards. In late November 2019, the NRA approved a draft screening document that concluded the upgraded plant will meet revised safety standards, introduced in January 2013. On 26 February this year, the NRA approved the final screening report, clearing the way for the unit to resume operation. The utility is still required to complete the countermeasure upgrades and obtain the approval of local authorities before it will be able to restart Onagawa 2.

The Onagawa plant was the closest nuclear power plant to the epicentre of the earthquake and tsunami of 11 March 2011, but sustained far less damage than expected. The earthquake knocked out four of the plant’s five external power lines, but the remaining line provided sufficient power for its three BWRs to be brought to cold shutdown. Onagawa 1 briefly suffered a fire in the non-nuclear turbine building. The plant was largely unaffected by the tsunami as it sits on an elevated embankment more than 14m above sea level, but the basement floors of unit 2 were flooded. A mission from the International Atomic Energy Agency in August 2012 concluded that the structural elements of the nuclear power station were “remarkably undamaged, given the magnitude of ground motion experienced and the duration and size of this great earthquake”.

Tohoku has already decided to decommission unit 1 of the plant and is considering applying to restart unit 3.

https://www.world-nuclear-news.org/Articles/Further-delay-in-completion-of-Onagawa-2-safety-up

May 14, 2020 Posted by | Uncategorized | , | Leave a comment

Fukushima Unit 2; New Containment Panorama Photos

u2_lower_pedestal_2019_web

April 1, 2019

A pair of new panoramic photos from inside Fukushima unit 2’s containment have been published. TEPCO provided the photos as part of ongoing updates on the disaster decommissioning work. The photos were stitched together from earlier containment inspection work then processed to bring out details of the photos. Also included in this report is details about the radiation and temperature readings inside containment, we explain that later in this report.

To read more on Fukuleaks:

http://www.simplyinfo.org/?p=17075&fbclid=IwAR1_Q_39LzdqLkkBzP9qwYPhAUrvsnpwvdtngLB9iCkKr4o5UVKxP262Yz4

April 8, 2019 Posted by | fukushima 2019 | , | Leave a comment

Fukushima Daiichi Unit 2 Newly Erected Platform’s Enigma

161215_03.jpg

A bird’s eye view of Units 1 and 2 from the hill

 

On December 15, 2016, the newly elected Kashiwazaki mayor, Mayor Masahiro Sakurai, who has called for a conditional restart of the Kashiwazaki-Kariwa nuclear power plant, one of the world’ largest nuclear plants, when he was elected mayor of this coastal city in Niigata Prefecture, northwestern Japan on Nov. 20, visited the Fukushima daiichi nuclear plant.

TEPCO, operator of the crippled Fukushima No. 1 nuclear plant, eager to restart reactors at the Kashiwazaki-Kariwa plant, invited him to tour the Fukushima Daiichi Nuclear plant, so as to show him that they fully control the situation there.

During the election campaign, Masahiro Sakurai said he would “approve a restart of the halted nuclear plant if safety is confirmed and certain conditions are fulfilled.”

One condition is the construction of a road that residents can use for evacuation in case of an emergency at the nuclear plant. Masahiro Sakurai also promised to start decommissioning older reactors at the plant.

Tepco made Mayor Sakurai visit the Fukushima Daiichi plant site, some of its buildings, its central control rooms 1 and 2, and the land side frozen by the impermeable ice wall.

On the same day, Tepco released 6 photos of Mayor Sakurai’s visit. One of the pictures was taken while Sakurai viewed  Units 1 and 2 from the hill, it shows a new platform erected by Tepco around unit 2. This new platform with extensive stairwells and levels running the length of the building, might be part of some work to remove the refueling floor so as to replace it with a defueling building.

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No information was yet provided by Tepco regarding that platform purpose.

Source : http://photo.tepco.co.jp/date/2016/201612-j/161215-01j.html

December 16, 2016 Posted by | Fukushima 2016 | , | Leave a comment

Containment Repair Research for Fukushima Unit 2 Ongoing

IRID_u2_concrete_inj_diagram_2016.jpg

IRID announced the details of the ongoing research for repairing the unit 2 suppression chamber.

Based on their previous investigations IRID has determined that there could be a hole or series of holes of around 50mm in the unit 2 suppression chamber.

The research work is to determine if filling with concrete that structure could work. The proposed plan would use a concrete pump truck with a 5 inch diameter flexible hose to inject concrete into the suppression chamber.

Initial work took place at the Ando Hazama Technical Research Institute (Tsukuba City, Ibaraki Prefecture) on October 15th.

It seems they succeeded in layering the concrete mixture,  sinking properly in the bottom of the suppression chamber tube. A 28 day pressure test will be conducted to assure the concrete properly plugs the leak.

Future work may be conducted at the new decommissioning research center at Naraha.

Source IRID :

http://irid.or.jp/topics/%e5%8e%9f%e5%ad%90%e7%82%89%e6%a0%bc%e7%b4%8d%e5%ae%b9%e5%99%a8%e6%bc%8f%e3%81%88%e3%81%84%e7%ae%87%e6%89%80%e3%81%ae%e8%a3%9c%e4%bf%ae%e6%8a%80%e8%a1%93%e3%81%ae%e9%96%8b%e7%99%ba%e3%80%80%e3%82%b5/

<添付資料11/1スケールS/C試験に関する現場状況・概要図>
http://irid.or.jp/wp-content/uploads/2016/10/20161018_001.pdf
<添付資料2:コンクリート打設進捗に伴う時経列事象・解説図>
http://irid.or.jp/wp-content/uploads/2016/10/20161018_002.pdf

October 21, 2016 Posted by | Fukushima 2016 | , , , , | Leave a comment