Operation of communication about the “scorpion” robot which will be sent to the confinement enclosure of reactor n ° 2

TEPCO and its partners launched a communication operation about the “scorpion” robot, which will be sent to the containment reactor of reactor n ° 2 in an attempt to locate the corium, ie the highly radioactive molten fuel, mixed with debris. It is not certain that the mission will be a success, the cleaning robot having lasted only two hours in this enclosure because of the extreme radiations, without being able to finish its task.

A press release announces what we already know and insists on the challenges: “every step is a new challenge for TEPCO, but TEPCo welcomes the challenges”. The company would be almost happy with the accident? It is accompanied by a promotional video with a comparison to the kendô fights posted on its Facebook page.

http://www.tepco.co.jp/en/press/corp-com/release/2017/1377951_10469.html

https://www.facebook.com/OfficialTEPCOen/videos/1346869308705698/

The Japanese nuclear industry wants to place itself on the decommissioning market and highlights the technologies being developed. This robot was designed by IRID, Toshiba and TEPCO. IRID benefits from public funds. As for Toshiba, it is almost bankrupt because of its nuclear branch and TEPCO is financially in a bad shape.

The press release and the video do not provide any relevant information and are in complete discrepancy with reality.

1. Current conditions of Unit 2 Primary Containment Vessel (PCV)

Nuclear fuel in the Primary Containment vessel (PCV) was exposed to the air and melted from the impact of March 2011 Great Earthquake.

As a result of the accident analysis, it was found that a portion of melted nuclear fuel might have been fallen inside the pedestal.

To remove fuel debris, it is necessary to investigate the PCV and clarify the conditions of debris and surrounding structures.

15-feb-2017-reactor-2-a

 

2. Outline of Unit 2 PCV investigation

[Purpose]: To obtain feedback information (deformation of platform, etc.) for the design and

development of next investigation devices inside the pedestal

To inspect conditions on the platform inside pedestal, fuel debris fallen to the CRD housing, and conditions of structures inside pedestal.

[Investigation point]: Platform and Control Rod Drive (CRD) will be investigated from the platform inside pedestal

15-feb-2017-reactor-2-b

3. Work steps for Unit 2 PCV investigation

15-feb-2017-reactor-2-c

 

4. Preparatory investigation results from X-6 penetration to CRD rail

15-feb-2017-reactor-2-d

 

4. Preparatory investigation results at the entrance of pedestal area

15-feb-2017-reactor-2-e

 

4. Preparatory investigation results of pedestal area

15 feb 2017 reactor 2 f.jpg

 

5. Additional results expected from the self-propelled investigation device

15-feb-2017-reactor-2-g

 

6. Investigation by the self-propelled investigation device to the end of CRD rail

15-feb-2017-reactor-2-h

 

6. Investigation by the self-propelled investigation device to the end of CRD rail

15-feb-2017-reactor-2-i

 

Reference: Investigation results on the platform inside the pedestal

15 feb 2017 reactor 2 j.jpg

Technical information for the media is available here:

In Japanese about the upcoming mission http://www.tepco.co.jp/nu/fukushima-np/handouts/2017/images1/handouts_170215_08-j.pdf

And in English http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2017/images/handouts_170215_01-e.pdf

And about radiation protection measures http://www.tepco.co.jp/nu/fukushima-np/handouts/2017/images1/handouts_170215_09-j.pdf

And in English http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2017/images/handouts_170215_02-e.pdf

Translated from L’ACROnique de Fukushima http://fukushima.eu.org/operation-de-communication-sur-le-robot-scorpion-qui-va-etre-envoye-dans-lenceinte-de-confinement-du-reacteur-n2/

What is Happening at Fukushima Daiichi?

The news headlines concerning Fukushima Daiichi over the last week have been rather confusing because some seem to imply that radiation levels have risen, as illustrated in this article by The Guardian:

Justin McCurry. February 3, 2017. Fukushima nuclear reactor radiation at highest level since 2011 meltdown. The Guardian,  https://www.theguardian.com/environment/2017/feb/03/fukushima-daiichi-radiation-levels-highest-since-2011-meltdown
Radiation levels inside a damaged reactor at the Fukushima Daiichi nuclear power station are at their highest since the plant suffered a triple meltdown almost six years ago.

I have not interpreted the latest news from TEPCO as indicating that radiation levels have risen.

Rather, I interpret the latest news as indicating that TEPCO was successful in getting a robot into an existing high-radiation area in the plant, under the reactor-pressure vessel of unit 2, as explained in this excerpt from an article published in The Japan Times:

Highest radiation reading since 3/11 detected at Fukushima No. 1 reactor. The Japan Times, Feb 3, 2017,http://www.japantimes.co.jp/news/2017/02/03/national/fukushima-radiation-level-highest-since-march-11/#.WJiKT_L5-YQ

The radiation level in the containment vessel of reactor 2 at the crippled Fukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, Tokyo Electric Power Co. Holdings Inc. said.

Tepco said on Thursday that the blazing radiation reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core…

Tepco also announced that, based on its analysis of images taken by a remote-controlled camera, that there is a 2-meter hole in the metal grating under the pressure vessel in the reactor’s primary containment vessel. It also thinks part of the grating is warped.

As the article observes, the hole was probably made when the fuel “escaped the pressure vessel after the mega-quake and massive tsunami triggered a station blackout.”

Simply Info, an excellent source of information and technical analysis about Fukushima, offers this summary analysis of the origins of the hole:

Fukushima Unit 2 Failure Point Found! Simply Info, Feb 2, 2017, http://www.fukuleaks.org/web/?p=16083

This large but concentrated hole appears to be the failure point for the unit 2 reactor pressure vessel (RPV). Melted fuel (corium) likely flowed through this hole and collected into the sump in the containment structure floor. The slow failure and small opening melted through the RPV likely allowed the molten fuel to burn down as it collected in the sump. This new visual evidence shows conditions that could have led to the molten fuel burning down into the reactor building concrete basemat. Without sufficient cooling, it could have potentially burned down through the basemat.

Simply Info has a follow up article where Nancy Foust offers her analysis. Here is her hypothesis concerning what happened to the fuel in reactor 2 after the earthquake 3/11:

Foust, Nancy. Feb 2, 2017. What The New Fukushima Unit 2 Inspection May Indicate. Simply Information, http://www.fukuleaks.org/web/?p=16050

What has been found seems to track with the theory of a slow failure and melt out that may have burned down into the concrete basemat rather than flowed out across the containment floor.

These reports beg the question as to where the reactor fuel from unit 2 is now located. Is it under the site? Is it in the basement? How structurally intact is the basement? TEPCO stated several years ago that water in the basement of unit 2 was encountering melted fuel and that this contaminated water was not entirely contained by the building (I have this documented in my published work on Fukushima).

And what are the conditions of reactors 1 and 3? These reactors remain too hot for robots.

There is a near continuous stream of atmospheric emissions that can be seen nightly on the webcam around unit 3. I always presumed that the MOX remains of unit 3 reactor’s fuel were responsible for that stream of visible heat/steam.

Could slumped fuel from unit 2 have ended up moving toward unit 3?

Here is a screenshot from today of the emission stream:

index.png
Well, no way to know for sure but I do feel safe concluding that Daiichi’s mysterious missing fuel is probably dispersing in ground water, ocean, earth, and atmosphere….

Previous Related Posts

Majia’s Blog: Making Sense of Fukushima

majiasblog.blogspot.com/2015/12/making-sense-of-fukushima.html

Dec 18, 2015 – As I’ve mentioned previously on my blog, there was no word on the fuel … are in danger of collapse due to an earthquake or liquefaction of the …

Majia’s Blog: Unit 4: Is There Intact Fuel Left Unburned?

majiasblog.blogspot.com/2012/09/unit-4-is-there-intact-fuel-left.html

Sep 28, 2012 – Majia here: When I listened to Arnie Gundersen’s recent interview and … 2012, the loose soil under Fukushima underwent liquefaction during a …

Majia’s Blog: Will Fukushima Daiichi Kill Vast Swathes of Life in the …

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Jan 11, 2014 – Majia here: Ok so strontium levels in the ground water and in ocean … This explains why site liquefaction is occurring at the Daiichi site. So, we …

Majia’s Blog

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Jan 29, 2017 – The New York Times has a poignant article about the plight of US service men who were required to clean up Enewetak atoll, part of the …

Missing: liquefaction

Majia’s Blog: Fukushima Daiichi Update

majiasblog.blogspot.com/2016/08/fukushima-daiichi-update.html

Aug 28, 2016 – Liquefaction has been a risk for years now at the plant. It is amazing (what’s left of) the buildings are still standing…. Posted by Majia’s Blog at …

Majia’s Blog: “Prosecutors drop TEPCO case over radioactive water …

majiasblog.blogspot.com/2016/03/prosecutors-drop-tepco-case-over.html

Mar 30, 2016 – [xv] Water saturation from the underground river and TEPCO’s injections contribute to ground liquefaction, which poses direct risks to the …

Majia’s Blog: Contaminated Water at Fukushima Daiichi Threatens …

majiasblog.blogspot.com.es/2014/02/contaminated-water-at-fukushima-daiichi.html

Feb 22, 2014 – The ground water saturation is contributing to ground liquefaction, which poses direct risks to the reactor buildings and common spent fuel pool …

Radiation level at Fukushima reactor highest since 2011 disaster; grating hole found

reactor 2 fab 2 2017.jpg

 

TOKYO (Kyodo) — The radiation level inside the containment vessel of the No. 2 reactor at the crippled Fukushima Daiichi nuclear complex stood at 530 sieverts per hour at a maximum, the highest since the 2011 disaster, the plant operator said Thursday.

Tokyo Electric Power Company Holdings Inc. also announced that based on image analysis, a hole measuring 2 meters in diameter has been found on a metal grating beneath the pressure vessel inside the containment vessel and a portion of the grating was distorted.

 

2 feb 2017.jpg

 

According to TEPCO, the extremely high radiation level was found near the entrance area in the space just below the pressure vessel. The previously highest radiation level monitored in the interior of the reactor was 73 sieverts per hour.

The hole could have been caused by nuclear fuel that penetrated the reactor vessel as it overheated and melted due to the loss of reactor cooling functions in the days after a powerful earthquake and tsunami on March 11, 2011 hit northeastern Japan.

According to the image analysis, about 1 square meter of the grating was missing.

The plant operator plans to deploy a robot at the bottom of the reactor containment vessel, which houses the reactor pressure vessel, to check the conditions there.

The analysis follows TEPCO’s discovery Monday of a black mass deposited on the grating directly beneath the pressure vessel, possibly melted fuel after the unit suffered a meltdown along with two other Fukushima Daiichi reactors.

Images captured using a camera attached to a telescopic arm on Monday also showed part of the grating has gone. A further analysis of the images found a 2-meter hole in an area beyond the missing section on the structure.

If the deposits are confirmed as fuel debris, it would be the first time the utility has found any at the three units that suffered meltdowns.

Following one of the world’s worst nuclear disasters since the 1986 Chernobyl catastrophe, the No. 1 to 3 reactors suffered fuel meltdowns.

Portions of the fuel in the reactors are believed to have melted through the pressure vessels and accumulated at the bottom of the containment vessels.

The actual condition of the melted fuel has remained unknown due to high radiation levels.

http://mainichi.jp/english/articles/20170202/p2g/00m/0dm/087000c

http://mainichi.jp/articles/20170203/k00/00m/040/079000c

 

2 feb 2017 2.jpg

Images indicate bigger challenge for TEPCO at Fukushima plant

A video taken on Jan. 30 shows the bottom of the No. 2 reactor’s pressure vessel at the Fukushima No. 1 nuclear power plant. Water used to cool the nuclear fuel is dripping, and possible melted fuel is seen strewn on grating for maintenance work. (Provided by Tokyo Electric Power Co.)

 

If confirmed, the first images of melted nuclear fuel at the Fukushima No. 1 nuclear plant show that Tokyo Electric Power Co. will have a much more difficult time decommissioning the battered facility.

The condition of what is believed to be melted fuel inside the No. 2 reactor at the plant appears far worse than previously thought.

Before the pictures were taken by a remote-controlled video camera on Jan. 30, TEPCO presumed that most of the nuclear fuel at the No. 2 reactor had remained within the reactor’s pressure vessel. That presumption was based on findings of a study conducted last year involving cosmic rays.

As a result, TEPCO did not expect the camera to detect possible nuclear fuel debris below the pressure vessel.

1 fev 2017 3.jpg

 

But the images showed black lumps scattered on a wire-mesh grating in the lower part of the containment vessel, which encloses the pressure vessel. This indicates that the fuel melted through bottom of the pressure vessel, spilled through the grating and fell on the floor of the containment vessel.

 

1-fev-2017-1

This image of the area below the No. 2 reactor’s pressure vessel at the Fukushima No. 1 nuclear power plant was taken on Jan. 30. Experts believe nuclear fuel melted the paint and components of equipment nearby and has hardened. (Provided by Tokyo Electric Power Co.)

 

The grating, which was used by maintenance workers before the disaster, was partially bent.

The images could show only part of the melted fuel in the No. 2 reactor. And there is still no indication on how widespread the black lumps were strewn, their volume and state.

TEPCO and government authorities in fiscal 2018 plan to decide on a method to retrieve the melted fuel from each of the three crippled reactors and start the removal work in 2021.

But a number questions remain unanswered, such as how to reduce workers’ radiation exposure, where the removed fuel will be kept, and when it will be disposed of.

The pictures raise another question: How will workers cut out the wire-mesh grating embedded with lumps of melted fuel?

The images were the first of possible nuclear fuel debris at the nuclear plant since the Great East Japan Earthquake and tsunami caused the triple meltdown there in March 2011.

 

1 fev 2017 2.jpg

Sasori (Scorpion), an investigative robot, is expected to be sent in the containment vessel of the No. 2 reactor of the Fukushima No. 1 nuclear power plant in February.

 

High radiation levels have prevented workers from entering the No. 2 reactor, as well as the No. 1 and No. 3 reactors at the plant.

A number of problems have hampered investigations by robots into the location of melted fuel at the No. 1 and No. 3 reactors.

http://www.asahi.com/ajw/articles/AJ201701310073.html

 

 

 

Footage points to difficulty in removing possible melted fuel at Fukushima plant

kjlmklmù.jpg

 

The footage released on Jan. 30 by Tokyo Electric Power Co. (TEPCO) showing what could be melted fuel inside the No. 2 reactor at the disaster-stricken Fukushima No. 1 Nuclear Power Plant has highlighted the difficulty of salvaging the object, which is apparently stuck to footholds and other equipment at the facility.
TEPCO took the footage as part of its in-house probe into the No. 2 reactor and found that black and brown sediments — possible melted fuel — are stuck inside the reactor’s containment vessel over an extensive area.

“If what was captured in the footage was melted fuel, that would provide a major step forward toward trying our hand at unprecedented decommissioning work,” said Yoshiyuki Ishizaki, head of TEPCO’s Fukushima Revitalization Headquarters, during a press conference in the city of Fukushima on Jan. 30. “The finding may provide a major clue to future work to retrieve the object,” he added.

At the time of the March 2011 meltdowns at the plant, there were 548 nuclear fuel rods totaling some 164 metric tons inside the No. 2 reactor, but they apparently melted down after the loss of power sources for the core cooling system, with part of the melted fuel penetrating through the pressure vessel before cooling down at the bottom of the containment vessel. The temperature of the reactor core topped 2,000 degrees Celsius at the time of the accident, melting metals including nuclear fuel inside the reactor.

The melted fuel has since come in contact with underground water flowing from the mountain side, generating radioactively contaminated water every day. In order to dismantle the reactor, it is necessary to take out the melted fuel, but high radiation levels inside the reactor had hampered work to locate the melted debris.

On Jan. 30, apart from the footage, TEPCO also released 11 pictures taken inside the No. 2 reactor. The images show the sediments in question stuck to metal grate footholds and water is dripping from the ceiling. Further analysis of those images may provide information on the current status of the disaster and positional clues to decommissioning work.

The in-house probe, however, has only focused on the No. 2 reactor, and there is no prospect of similar probes into the No. 1 and No. 3 reactors starting anytime soon as they were severely damaged by hydrogen explosions following the 2011 meltdowns.

In April 2015, TEPCO introduced a remote-controlled robot into the No. 1 reactor by way of a through hole in its containment vessel, but the device failed to locate melted fuel inside due to high radiation levels. While the utility is planning to send a different type of robot into the No. 1 reactor this coming spring, it would be difficult to carry out a survey similar to that conducted at the No. 2 reactor, as radiation levels are high around the through hole in the No. 1 reactor’s containment vessel, from which a device could access to right below the No. 1 reactor.

The No. 3 reactor, meanwhile, holds roughly 6.5-meter-deep contaminated water inside its containment vessel, a far larger volume than that accumulated at the No. 1 and No. 2 reactors. TEPCO has thus been developing a robot that can wade through water.

http://mainichi.jp/english/articles/20170131/p2a/00m/0na/007000c

Possible nuclear fuel find raises hopes of Fukushima plant breakthrough

30 jan 2017 guardian.jpg

Material found below the damaged No 2 reactor at Fukushima nuclear plant, believed to be melted fuel, from footage taken on 30 January.

Operator says it has seen what may be fuel debris beneath badly damaged No 2 reactor, destroyed six years ago in triple meltdown

Hopes have been raised for a breakthrough in the decommissioning of the wrecked Fukushima Daiichi nuclear plant after its operator said it may have discovered melted fuel beneath a reactor, almost six years after the plant suffered a triple meltdown.

Tokyo Electric Power (Tepco) said on Monday that a remote camera appeared to have found the debris beneath the badly damaged No 2 reactor, where radiation levels remain dangerously high. Locating the fuel is the first step towards removing it.

The operator said more analysis would be needed before it could confirm that the images were of melted uranium fuel rods, but confirmed that the lumps were not there before Fukushima Daiichi was hit by a powerful earthquake and tsunami on 11 March 2011.

The tsunami, triggered by a 9.0-magnitude quake, killed more than 18,500 people along the coast of north-east Japan and destroyed the backup power supply at Fukushima Daiichi, triggering the world’s worst nuclear accident since Chernobyl 25 years earlier.

Meltdowns in three of the plant’s six reactors forced about 160,000 people to evacuate and sent plumes of radiation across the Fukushima region. Many of the evacuees are unlikely to return home.

If Tepco can confirm that the black mass comprises melted fuel, it would represent a significant breakthrough in a recovery effort that has been hit by mishaps, the buildup of huge quantities of contaminated water, and soaring costs.

This is a big step forward as we have got some precious data for the decommissioning process, including removing the fuel debris,” a Tepco official said.

Using a remotely controlled camera attached to the end of a 10.5-metre-long telescopic arm, Tepco technicians located black lumps on wire-mesh grating just below the reactor’s pressure vessel, local media reported.

The company plans to send a scorpion-like robot equipped with cameras, radiation measuring equipment and a temperature gauge into the No 2 reactor containment vessel next month, according to the Asahi Shimbun.

Three previous attempts to use robots to locate melted fuel inside the same reactor ended in failure when the devices were rendered useless by radiation.

Developing the means to remove the fuel – a task Tepco has said will become easier once it can gauge its condition – would be the biggest step forward in the mission to clean up Fukushima Daiichi since the removal of hundreds of spent fuel rods from a damaged reactor building in late 2013.

The delicate, potentially dangerous task of decommissioning the plant has barely begun, however.

Japanese media said last week that plans to remove spent fuel from the No 3 reactor building had been delayed, while decommissioning the entire plant was expected to take at least 40 years.

In December, the government said the estimated cost of decommissioning the plant and decontaminating the surrounding area, as well as paying compensation and storing radioactive waste, had risen to 21.5 trillion yen ($187bn), nearly double an estimate released in 2013.

A government committee estimated that 2.4 trillion yen of the total cost would be passed on to consumers through higher electricity bills.

https://www.theguardian.com/environment/2017/jan/31/possible-nuclear-fuel-find-fukushima-plant

 

TEPCO may have located melted fuel for 1st time at Fukushima plant

reactor-2-30-jan-2017-a

Tokyo Electric Power Co. said Jan. 30 it may have finally pinpointed the location of melted fuel at the Fukushima No. 1 nuclear plant, nearly six years after the triple meltdown unfolded there.

If confirmation is made, it would represent a breakthrough in the daunting task of decommissioning the stricken nuclear plant.

reactor 2 30 jan 2017 b.jpg

A remote-controlled camera fitted on a long pipe detected black lumps on grating in the lower part of the containment vessel of the No. 2 reactor at the plant early on Jan. 30, TEPCO said.

The wire-mesh grating is located below the pressure vessel of the reactor. The lumps were not there before the Great East Japan Earthquake and tsunami on March 11, 2011, caused the nuclear disaster, according to TEPCO.

reactor 2 30 jan 2017 c.jpg

The utility plans to determine whether the lump is melted fuel based on images and radiation levels taken by an investigative robot and other data. The robot, called “Sasori” (scorpion) and fitted with two cameras, a dosimeter and a temperature gauge, will be sent into the No. 2 reactor containment vessel next month.

reactor 2 30 jan 2017 d.jpg

High radiation levels have hampered efforts at the nuclear plant to determine the condition and location of melted nuclear fuel.

TEPCO tried–and failed–three times to locate melted fuel using an industrial endoscope at the No. 2 reactor.

The latest investigation inside the No. 2 reactor began on Jan. 26 to locate the melted fuel.

The company is preparing to devise a method to retrieve the melted fuel in fiscal 2018 as part of the decommissioning work.

http://www.asahi.com/ajw/articles/AJ201701300058.html