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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

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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

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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

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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