SimplyInfo » Entries tagged with "unit 1"
TEPCO To Remove Cover On Unit 1 This Fall
[Translate] TEPCO will remove the cover on unit 1 at Fukushima Daiichi this fall. The cover was hastily put over the unit in 2011 in an attempt to lower releases. TEPCO did not say why this work has suddenly been jumped ahead of other work. Most of the roadmap plans TEPCO has announced put unit 1 far down the list of priorities. To remove the spent fuel TEPCO will need to remove the cover, something they say will raise radiation levels. They will also need to remove the remains of the roof and the two cranes to do the work. It was not mentioned how much the radiation levels would rise during this work. Meanwhile the Japanese government has been pushing to reclassify more and more areas near the plant as being … Read entire article »
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Unit 1 Access Hatch Inspection Gives Clues
[Translate] TEPCO sent a pair of robots in to inspect the personnel access hatch for unit 1 recently. Upon reviewing the video we found a few things of significance. TEPCO obviously had some motivation for checking this room. A large diameter steam pipe runs through the adjacent room and goes through the thick concrete containment wall. The pipe is a steam line for the HPCI system. The radiation levels near the pipe jump to a range of 120-155 mSv/h and water can be seen on the floor. Salt staining is also evident below the pipe leading to a floor drain. This drain could be part of a controlled liquids system meaning that water running to the drain may be captured by radioactive waste systems at the plant. The leak appears to have … Read entire article »
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Pre-Tsunami Damage At Unit 1 Fukushima Daiichi
[Translate] Concerns about damage to unit 1 and possibly other units having happened before the tsunami hit the plant still exist among experts and those who witnessed the disaster. Many worked cited seeing pipes buckle, break, leak or fall off of walls as they fled the unit during the earthquake. In an effort to document these events and investigate the possibility of earthquake induced damage playing a role in the disaster we have started a page to document those findings. The permanent page can be found here or in the Fukushima Status menu on the home page. http://www.simplyinfo.org/?page_id=10166 This article would not be possible without the extensive efforts of the SimplyInfo research team Join the conversation at chat.simplyinfo.org All content is copyright SimplyInfo.org. Content may also be copyright of other specific original authors or creators and was … Read entire article »
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TEPCO Announces Plan To Look At Reactor Vessel In Unit 2
[Translate] TEPCO announced a plan that should enable them to look inside unit 2 and inspect the reactor vessel directly. TEPCO plans to use the long scope camera to conduct the work. They will send the scope down the control rod replacement rail into the pedestal, this will allow a clear view of the underside of the steel reactor vessel. Since the bottom of this vessel is the likely melt through location this work may give some major clues to what happened at unit 2. From the handout it appears they practiced the work at unit 5. This is a common tactic TEPCO has used to allow workers to be familiar with the task before going into the high radiation environment in the other units. This work will be done in late March, … Read entire article »
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Unit 1 Torus Radiation Shows Possible Source Location
[Translate] TEPCO recently inspected the unit 1 torus room for a second time as we reported here. Workers involved in the inspection work made the comment that the torus tube and the proximity to the probe may play a role in the new radiation readings. The levels being found within the torus indicate that work in this region of the building could prove quite difficult and may require specialized robotic equipment. February 2013 Unit 1 torus inspection, probe (blue line) compared with torus and water proximity. We have reviewed multiple handouts issued by TEPCO concerning the inspection of the torus areas at 2 locations along the west side of the reactor building. The first being in June 2012 and the second in Februrary 2013. Each was conducted at different locations about 16900mm apart … Read entire article »
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Unit 3 Spent Fuel Pool Update
[Translate] A series of videos were released recently showing sections of the spent fuel pool at unit 3 of Fukushima Daiichi. While they do not show all areas of the pool they do give some hints at the condition of the pool. These are the best quality videos to date. This may be do to attempts to clear the pool water to aid the retrieval of objects in the pool. Videos: http://www.youtube.com/watch?v=ZUmXNNjiS0E&list=UUs6GVH_Px26xPssNOjiJp8Q&index=6 http://www.youtube.com/watch?v=mHeLD9-M8Qs&list=UUs6GVH_Px26xPssNOjiJp8Q&index=5 http://www.youtube.com/watch?v=r3snw1g-Z-0&list=UUs6GVH_Px26xPssNOjiJp8Q&index=4 http://www.youtube.com/watch?v=HiCvN7Kqmh8&list=UUs6GVH_Px26xPssNOjiJp8Q&index=3 http://www.youtube.com/watch?v=hnkvcsfBA04&list=UUs6GVH_Px26xPssNOjiJp8Q&index=2 Images: We have an extensive collection of large format images based off of the new video inspections. These provide an improved visual with a high level of detail. View the entire image collection of the new unit 3 videos here on our Flickr page: http://www.flickr.com/photos/simplyinfo/sets/72157632820926995/ Findings and comments: The photo above reveals potential damage to fuel assembly lifting bails. There is perhaps 100 tons of debris … Read entire article »
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Unit 1 Torus Inspection Review
[Translate] New work done around February 21 to 22 has been posted by TEPCO and confirmed by workers. The newest work was done at a new location about 17 meters from the previous torus inspection location. (ignore the blue route lines, those are from a previous use of the floorplan diagram at another unit.) The video was considerably different than what was seen on the previous torus inspection. The newest inspection video can be found here on our Youtube channel Our work and data from the previous torus inspection back in June 2012 can be found here. We also processed the new inspection video into individual images that can be found on our Flickr page. Two TEPCO handouts from the newest torus inspection: U1_torusday2_handouts_130222_05-e U1_torusday1_handouts_130220_02-e Workers drilled a large hole into the concrete floor in the north west corner of the … Read entire article »
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Public Spin On Fukushima Coming Undone
[Translate] TEPCO’s efforts to avoid outside inspections of the unit 1 reactor have caught up with them. After it was recently pointed out to the Diet that TEPCO had lied to the investigation committee last year in an effort to avoid an inspection, now it appears one is pending. The Diet has asked the new nuclear regulator to conduct an inspection of the isolation condenser system in unit 1 and they appear ready to do so: “If the condensers are found to show damage consistent with shaking in an earthquake there would be case for higher standards in nuclear plant design—with important implications for existing reactors built to lesser tolerances. But the Nuclear Regulation Authority chairman warned against premature conclusions. “We will not pre-judge the investigation,” Tanaka said. He added that an investigation … Read entire article »
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Asahi Shimbun Calls For New TEPCO Investigation
[Translate] An editorial put out today by Asahi Shimbun calls for a new Diet investigation into the Fukushima Daiichi accident. Events came out this week that showed TEPCO has purposely deceived members of the Diet accident investigation committee. TEPCO lied about conditions within the unit 1 reactor in an attempt to dissuade the investigators from doing an on site inspection of the emergency cooling system at unit 1. This information regarding 1′s cooling system is critical as the investigation concluded mostly based on TEPCO’s disclosed information that the cooling systems were not damaged by the earthquake. There has long been concern that something damaged one portion of the isolation condenser system at unit 1 during the quake causing it to not work. Worker interviews in The Atlantic in 2011 disclosed that they saw … Read entire article »
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TEPCO New Video; Unit 1 Needed Venting Again Weeks After Disaster
[Translate] In a new video release by TEPCO, managers discussed venting the unit 1 reactor again almost two weeks after the disaster began. Asahi Shimbun reported this exchange between Yoshida at Fukushima Daiichi and executives in Tokyo. “At 11:20 a.m. on March 23, 2011, Masao Yoshida, then chief of the Fukushima No. 1 plant, asked the Tokyo head office to confirm procedures for venting a containment vessel. “It will be an extremely major issue, and we need to coordinate with the head office,” Yoshida said. At that time, pressure at the No. 1 reactor was climbing to the maximum level the reactor was designed to withstand. The pressure did not fall until the night of March 24.” The Asahi Shimbun report does not say if the reactor was actually vented again or if … Read entire article »
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New Paper: Gamma Radiation Damage To Fukushima Units 1- 4 Spent Fuel Pools
[Translate] SimplyInfo.org has released another new paper taking an in depth look into the ongoing challenges at the Fukushima Daiichi nuclear plant. This new work investigates the technical issues involved with the ongoing degradation of the spent fuel pools. Gamma radiation is an ongoing problem for the steel and concrete that composes the spent fuel pools. Aspects of the disaster have drastically changed that damage mechansim. The paper can be found online and also in PDF format for download or reading on book readers. Gamma Radiation Damage To Fukushima Units 1- 4 Spent Fuel Pools http://www.simplyinfo.org/?page_id=9353 This article would not be possible without the extensive efforts of the SimplyInfo research team Join the conversation at chat.simplyinfo.org All content is copyright SimplyInfo.org. Content may also be copyright of other specific original authors or creators and was reproduced … Read entire article »
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What The Melted Fuel At Fukushima Unit 1 Looked Like In The Pedestal
[Translate] A recent report by Sandia National Lab indicated that about 140,000kg of melted fuel and debris was released out of the unit 1 reactor vessel. These calculations were part of a larger effort to model the progression of the meltdowns at Fukushima using the known reactor data. “The present analysis shows gross failure at about 14 hours when approximately 140,000 kg of core materials was released to the drywell cavity region” We took those quantities and attempted to visualize what that bulk of melted fuel would look like compared to the pedestal region below the reactor vessel. The rough volume of fuel presented as a total amount gives a better idea how much melted fuel is being dealt with at unit 1. The height range is based on the volume and density range for … Read entire article »
Filed under: Reactor 1, The Latest
TEPCO Restarts Nitrogen Injection In Unit 1 Suppression Chamber
[Translate] From today’s TEPCO report, they intend to restart nitrogen injection into the torus (suppression chamber). This has been done frequently over the last three months to combat hydrogen build up in the torus. Current containment hydrogen levels are at 0%. There has been some concern over the location of the hydrogen sensors for unit 1 containment. Based on TEPCO documents they currently read containment hydrogen is out in the venting gas handling system. (Machine Translation) “As proactive in order to check the status of hydrogen generation by water radiolysis in the 1/8 10:37 suppression chamber [No. 1], Resume the continuous inclusion of nitrogen gas into the suppression chamber.” This article would not be possible without the extensive efforts of the SimplyInfo research team Join the conversation at chat.simplyinfo.org All content is copyright SimplyInfo.org. Content may also … Read entire article »
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Fire Risk At Older Japan Reactors Shows Potential Worldwide Problem
[Translate] The NRA announced recently that reactors built before 1975 likely have sub standard fire protection designs. This includes having important cables coated in fire resistant insulation, isolating and protecting cables and creating barriers to prevent fires from spreading to other areas of critical equipment. NRA announced that about 10 reactors in Japan likely have these outdated unsafe systems. The 1975 changes in Japan were only mandatory on new reactors being built, any retrofit of old units was voluntary by the reactor owners. Mainichi found that 13 nuclear plants in Japan have these unsafe cables. Some operators coated these vinyl or polyethylene cables with a resin to give them some fire resistance. NRA claims the resin doesn’t prevent the coating underneath from melting and the resin will degrade with age. Mainichi also … Read entire article »
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Unit 1; Post Quake Reaction & Torus Oddity Indicate Larger Problem
[Translate] We have reported extensively about a phenomenon going on inside unit 1 since the accident. Whenever there is a strong quake, the radiation in the Drywell B sensor goes up considerably, pressure and other readings tend to also fluctuate in unison. After the initial meltdowns these reactions were quite intense. Now 1 year and 9 months into the disaster we still see this same activity. The recent 7.3 quake at Fukushima caused this same reaction. Drywell B radiation went from 2.99 to 4.71. Swings up into the 3′s or low 4′s happen but the high 4′s was unusual. One pressure sensor jumped from .1417 to .1420 post quake then settled back down. As has always been the case the suppression chamber radiation readings do not go up post quake. Inspections of the … Read entire article »
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Hydrogen Stays Elevated At Unit 1 Fukushima Daiichi
[Translate] Hydrogen in the containment of unit 1 has continued to be elevated as they work to purge hydrogen from the torus. The 5am and 11am reports for today showed continual elevated levels with a slight downward trend. The purge rate was slightly higher at 5am indicating TEPCO may have increased the rate they removed air and gasses from the containment structure to combat increasing hydrogen levels. 5am Oct 29: 1.56% 1.57% 11am Oct 29: 1.55% 1.55% This article would not be possible without the extensive efforts of the SimplyInfo research team Join the conversation at chat.simplyinfo.org All content is copyright SimplyInfo.org. Content may also be copyright of other specific original authors or creators and was reproduced here with limited permission. While we welcome the sharing of information or promoting our work, please do so with respect to the large … Read entire article »
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Unit 1 Refueling Floor Video & Exclusive New Photos
[Translate] TEPCO’s lightbulb balloon inspection of the refueling floor did result in some interesting findings. The overhead crane was found to be significantly damaged and partially resting on the refueling crane. This may complicate safe removal of the cranes and debris from unit 1. The power of the hydrogen blast itself is evident in some of the findings on the video. Videos at the end of the article. Overhead crane, broken open above the refueling crane. Another view of the overhead crane. W hat appears to be the other portion of the overhead crane on the refueling deck. A thick steel beam pulled apart and split in half shows the massive force of the hydrogen explosion at unit 1. This heavy steel I-beam curved during the explosion. This blue object appears to be some sort of small … Read entire article »
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TEPCO Trying To Remove Hydrogen From Torus
[Translate] This was initially reported in a TEPCO roadmap report that they were monitoring a pocket of hydrogen that has developed in the torus. The torus is almost full of water, that small air gap above the water in the torus holds the hydrogen concentration. We previously detailed TEPCO’s now ongoing work to deal with the hydrogen in the torus. TEPCO assumes the hydrogen in the air gap is left over from the initial accident. TEPCO has known about the hydrogen problem for a while, they do not state why they chose now to purge it. The more concerning aspect of this is the air density concentration of the hydrogen in the torus air gap. At 4% concentrations hydrogen can explode. Hydrogen build up is thought to have been the cause of … Read entire article »
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TEPCO’s Lightbulb Balloon Inspects Upper Floors
[Translate] TEPCO did another inspection of unit 1. They previously used a balloon that looked like a beach ball to float a camera up through the equipment shaft. That balloon was unable to go all the way up due to debris in the way. The new and improved balloon appears to be a promotional balloon shaped like a lightbulb complete with brass screw in base. Besides the creative use of an advertising tool, the effort did manage to inspect all floors. The radiation readings were in the 20-150 mSv/h range. Images of the refueling floor showed the refueling crane and also that the overhead crane had bent and fallen on top of the refueling crane. Workers took about a 3.81 mSv dose for their work. Overhead crane beam upper left Equipment shaft and balloon. Refueling … Read entire article »
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Unit 1 Torus Gas Inspection
[Translate] TEPCO posted a section in a larger roadmap in Japanese about an investigation into the torus of unit 1 over gas build up concerns. Below is a rough machine translation of the document section. Update: Fukushima-Diary just posted an NHK video explaining the hydrogen & krypton buildup in the torus. Apparently it has been an issue since April and TEPCO thought they needed to intervene. For the nitrogen injection to the S / C Unit 1 October 22, Heisei 24 Tokyo Electric Power Co., Inc. Method of estimation and verification mechanism Pressure drop ① S / C pressure (← D / W Due to) lowering of water level and PCV Water level in the S / C that is reduced, The top gas in the closed space (water Iodine, Kr85) is vacuum break device Discharged to the D / W through … Read entire article »
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