Entombing Fukushima

[don]

TEPCO has decided to entomb Reactor 1, which is confirmed in a state of full meltdown, in a sarcophagus shell to contain the high amounts of radiation that escape every day. Simulations have led experts to believe that meltdown occurred after 3.5 hours after the cooling systems stopped. While TEPCO finishes the designs for its containment structure in Japan, in the Ukraine, the Chernobyl sarcophagus is also being re-encased. The installment of the cover is a temporary emergency measure, and its ability to withstand seismic activity is unknown.

The full situation inside of Reactor 1 has not been released to the public yet, but monitoring of pressure readings inside of the RPV show that the pressure is equal to atmospheric pressure and dropping. Both Reactor 2 and Reactor 3 RPV pressure levels currently register a lower than atomospheric pressure reading.

Video inside of the plant on June 3rd, provided footage of steam forced out of the reactor that registered over 4 Sieverts. While TEPCO continues to claim the pressure levels recorded in the Containment Vessel mean that the melted core has not yet escaped all containment measures, they do admit that contaminated water continues to leak from the Containment Vessel. There is estimated to be at least one 7 centimeter hole in the CV. TEPCO has announced that they do plan to install a new pressure gauge for the CV at some point in the future, and also must replace the broken radiation detection instrument in the drywell.

Hiroaki Koide of Kyoto University Research Reactor Institute is quoted by Mainichi Shinbun as saying that the melted core of the Reactor 1 is not just out of the Reactor Pressure Vessel but out of the Containment Vessel.

Hiroaki Koide of Kyoto University Research Reactor Institute points out that TEPCO could have foreseen the core melt at an early stage when the cooling of the reactor stopped due to the power failure. TEPCO's assessment that the damage to the fuel was limited has turned out to be completely wrong. The disclosure of the data came too late."

According to TEPCO, the data analysis shows that damage to the RPV is not extensive. However, Koide thinks "The RPV has been completely damaged, the melted core bore a hole at the bottom of the Containment Vessel, causing the large amount of contaminated water to leak into the ground beneath the reactor building."







While the question of whether the Corium has escaped the building remains unanswered, the radiation levels inside and outside of the Reactor 1 building remain a constant enemy for workers. Beside the 4,000 mSv steam, in May readings inside of the building registered 1,000 mSv on the 2nd floor, 2,000 mSv inside the southeast double door, and it is estimated at least 3,000 tons of contaminated water had leaked into the basement by mid-May. By that point TEPCO had injected over 10,000 tons of water inside of the RPV, and the exact location of the other 7,000 tons was never produced. These are just a few of the many obstacles that face TEPCO as they attempt to keep the situation under control to be able to complete the sarcophagus construction.

How much melted fuel is at Fukushima Daiichi?





These estimates are based off of public information regarding amounts of fuel stored in Reactor 1, Reactor 2, and Reactor 3. All listed reactors are currently believed to be in a state of full-meltdown, but the actual amount of corium is likely greater than numbers used as other elements are incorporated during a meltdown.





These estimates are based off of public information regarding amounts of fuel stored in Reactor 1, Reactor 2, and Reactor 3. All listed reactors are currently believed to be in a state of full-meltdown, but the actual amount of corium is likely greater than numbers used as other elements are incorporated during a meltdown.

The covering structure was initially designed with a steel frame and a resin-coated polyester covering, but was redesigned with concrete walls. TEPCO has not provided what information was used to determine the ability of the ground around the sarcophagus to hold the additional weight of the structure and original reactor building. There is also no mention of what would happen if the melted corium, which thought to have escaped containment, were to cause an explosion inside of the structure.

Construction on the concrete and steel structure will begin on June 27th, according to the latest updated plans released by TEPCO. High levels of radiation will severely limit the amount of work that can be done on-site, and will also accelerate the aging of materials used for the sarcophagus. This is one of the lessons learned from the construction of the first sarcophagus at Chernobyl, and to combat the on-site radiation, TEPCO will build many parts off-site. The utility hopes to finish prefabrication of the frame and have it shipped to the site by late July.

The sarcophagus that encases Reactor 4 at Chernobyl was also constructed in haste, and is currently in an desperate need of repair. The greatest problems with the Chernobyl sarcophagus is its lack of stability, which will be a even greater problem at Fukushima Daiichi.

The assembly process is to be primarily accomplished by remotely controlled cranes and other automated vehicles, in order to limit the amount of radiation workers are exposed to. This is the plan at least, at Chernobyl initially robotic equipment was used to try and clear debris from the roof and around the damaged reactor, but the high levels of radiation caused all the equipment to fail. This forced the Soviet Government to send in over 500,000 bio-robots from all around the Soviet Union.


The cranes to be used at Fukushima Daiichi are capable of transporting over 750 tons per load, but even the largest cranes in Japan can be rendered scrap if the wiring and electrical components are compromised by radiation. To connect the frame, TEPCO developed a new connection part to try and create a functional fitting connection to keep the workers from entering the assembling area as little as possible.

If the shroud is completed, it must also be able to prevent precipitation from entering the reactors, and limit the emission of radiation from the reactors and spent fuel pools. Despite all of the best made plans, utility officials admit they are unsure of if construction can be completed, if it will perform as expected, and how long it may last.

Some of the many unanswered questions are, how much radioactive waste will need to be removed prior to construction, and how will TEPCO accomplish this. If the remote-controlled equipment fails, what is the contingency plan?

Chernobyl Sarcophagus

Similar to Fukushima, the initial Chernobyl Structure was also constructed as an emergency measure to prevent radiation from being released into the atmosphere and further contaminating the northern hemisphere. Only 200 tons of radioactive corium is locked within the structure, a fraction of the amounts estimated to be in the reactors at Fukushima Daiichi. The radioactivity inside of the sarcophagus prevented work from being completed at the time.


1. The structure at Chernobyl was constructed out of more than 7,000 tons of steel and 410,000m3 of concrete
2. Due to harsh construction environment the structure was completed even though it had many defects and cracks that still allowed some radiation to be dispersed.
3. Has not lived up to design expectations
4. Current sarcophagus is not in good shape at all
5. Current sarcophagus would collapse in an earthquake measuring 6 or more
6. Europe is constructing a new dome over contaminated plant to prevent another nuclear disaster.
7. Construction on a new sarcophagus began in 2010 and is expected to be completed in 2012
8. Funding for the new containment shelter was paid for by many countries
9. The new structure completed in 2011 will require further upgrades in 100 years

In neither Fukushima nor Chernobyl was a per kilowatt cost included . . . .


http://www.globalresearch.ca/index.p...t=va&aid=25423

[Starving Steve]

Re: Entombing Fukushima

What you forget to say is that virtually all of Fukishima was destroyed by the largest earthquake ever recorded in history--- a 9.0 magnitude earthquake caused by nature and not by TEPCO's power plant at Fukishima. What you also forget to say is that a 45-foot high tsunami devasted Fukushima as a result of the earthquake. The world has never experienced anything like this before, or at least as long as mankind has been keeping records.

There is no connexion with the damage at Fukushima to atomic power. NONE! And one more important detail that you conveniently omitted: NO-ONE has died from radiation at Fukushima, even after three melt-downs at TEPCO's Fukushima plant.

Now you can make a strong case that a geographer should have been consulted in determining a proper location for TEPCO's power plant. But you can not blame the damage at Fukushima onto atomic power. The damage was due to the 9.0 magnitude earthquake and the 45-foot high tsunami, both caused by nature and not by TEPCO.

A couple more minor details that are important: 1.) No-one died from radiation at Fukushima because the human-body repairs cell damage done by radiation. This natural repair system in the human-body (and all living things on this planet) is due to evolution. Without natural repair of radiation damage, life on Earth would not have been possible. 2.) Where was the measurement of 4 sieverts taken? For that, I need a more specific location. Was it at the fence of the TEPCO site, or was it inside a containment building, or was it in downtown Fukushima? Was the measurement taken next to the core of one of the reactors? If so, which one? How far from the core?

As usual, I am lost. Help me out here. Be specific. And what is the issue that you have with TEPCO? What did you want TEPCO to do? Did you want TEPCO to tell Nature or the Earth or God to not launch mankind's first encounter with a 9.0 earthquake and a 45-foot tsunami? I think TEPCO did all that it could possibly have done. This was the rarest of events in the history of the Earth, and an event that would be all but impossible to plan for.

[Starving Steve]

Re: Entombing Fukushima

Don's post uses the word, "entomb". That word has very negative connotations in English, and it means to bury forever in the Earth, like a mummy would get buried inside a vault or a grave.

What are the alternatives to atomic power for Fukushima?

A coal-fired power plant would have been destroyed too, but there would have been less of a mess. However, the coal miners in any coal mine near Fukushima would have been entombed in such a disaster. Hundreds of miners could have died.

A natural gas-fired power plant would have been destroyed too, but there would be less of a mess. However, the gas trunk-lines would have been severed, and fires would have been horrendous. It would have been a San Bruno-like holocaust all over again, but this time in Fukushima to add to the suffering there.

A hydro-electric power plant next to a dam, would have also been destroyed, but there would have been less of a mess. The power plant would be easy to fix now...... However, the dam holding-back the water would likely have split-open in a 9.0 earthquake, and the wall of water coming out of that dam would have killed hundreds, if not thousands of people.

The bottom-line Don is: What do you want Fukushima to do? The people of Fukushima and the rest of Japan need power. And what do you want TEPCO to do now?

If I were TEPCO, I would re-build the Fukushima plant as soon as possible. I would also try to build a sea-wall. I would also try to build-in more redundancy into the plant design, especially for cooling-water. This should be easy to do, but I confess that I am not a nuclear engineer. I would envision putting water-tanks onto tractors, and having those tanks filled with water and available at all times. I would keep the tractors fueled-up and ready to go anywhere, on-notice, anytime.

[don]

Re: Entombing Fukushima

FYI:

A sarcophagus is a funeral receptacle for a corpse, most commonly carved or cut from stone. The word "sarcophagus" comes from the Greek σαρξ sarx meaning "flesh", and φαγειν phagein meaning "to eat", hence sarkophagus means "flesh-eating"; from the phrase lithos sarkophagos (λιθος σαρκοφάγος). Since lithos is Greek for stone, lithos sarcophagos means 'flesh eating stone'. The word came to refer to the limestone that was thought to decompose the flesh of corpses interred within it.

That was the word of choice to describe the solution for Chernobyl.

Entomb is the word chosen for the coverage of the solution for Fukushima.

[c1ue]

Re: Entombing Fukushima

Again, a wide divide between panic mongerer and what the IAEA is reporting:

http://www.iaea.org/newscenter/news/...iupdate01.html

Presentations:
→ Summary of Reactor Status
→ Fukushima Radiological Monitoring and Consequences
→ Fukushima Marine Environment Monitoring
→ Watch Video
On Thursday, 2 June 2011, the IAEA provided the following information on the status of nuclear safety in Japan:
Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious.
The IAEA receives information from various official sources in Japan through the Japanese national competent authority, the Nuclear and Industrial Safety Agency (NISA). This Update Brief is based on information issued by the IAEA Incident and Emergency Centre up to 16:00 UTC on 31 May 2011.
1. Fukushima Daiichi Nuclear Power Plant Status
Tables 1 - 4 track progress for Units 1 - 4 towards fulfilling the three basic safety functions of the IAEA safety standards: prevention of criticality, removal of decay heat and mitigation of radioactive releases. The tables replace the three-colour table that was used previously. The charts are cross-referenced to the Tokyo Electric Power Company (TEPCO) "Roadmap" plan to bring the nuclear reactors and the spent fuel pools at the Fukushima Daiichi plant to a stable cooling condition and to mitigate radioactive releases.
On 17 May 2011, TEPCO provided a status report against the TEPCO "Roadmap" showing progress since the Roadmap was issued on 17 April 2011. While the basic policy and targets defined in the Roadmap remain, several changes were made to account for new information obtained and progress made to date.
On 13 May TEPCO commenced the preparatory work for the installation of a cover for the reactor building of Unit 1. The reactor building cover will be installed as an emergency measure to prevent the dispersion of radioactive substances until mid- to long term measures, including radiation shielding, are implemented.
TEPCO has reported that information obtained after calibration of the reactor water level gauges of Unit 1 shows that the actual water level in the Unit 1 reactor pressure vessel was lower than was indicated, showing that the fuel was completely uncovered. The results of provisional analysis show that fuel pellets melted and fell to the bottom of reactor pressure vessel at a relatively early stage in the accident.
TEPCO reported that "most part of the fuel is considered to be submerged in the bottom of reactor pressure vessel and some part exposed." TEPCO also reported that leakage of cooling water from the reactor pressure vessel is likely to have occurred. However, TEPCO considers that the actual damage to the reactor pressure vessel is limited, on the basis of the temperatures now being measured around the reactor pressure vessel.
The results of the analysis are provisional; TEPCO will continue to conduct investigations. Similar analyses will be conducted for Units 2 and 3 when radiation levels allow calibration of the instrumentation.
Nitrogen gas is still being injected into the containment vessel in Unit 1 to reduce the possibility of hydrogen combustion inside the containment vessel.
In Units 1, 2 and 3 fresh water is being continuously injected both via the feed water system lines and the fire extinguishers lines into the reactor pressure vessel; temperatures and pressures remain stable.
To protect against potential damage as a result of future earthquakes, TEPCO started work on 9 May to install a supporting structure for the floor of the spent fuel pool of Unit 4. TEPCO has formulated the hypothesis that the damage to the Unit 4 building could have been caused by hydrogen generated at Unit 3 that flowed into Unit 4.
Fresh water is being injected as necessary into the spent fuel pools of Units 1 - 4. Water supply from concrete pump trucks is being gradually replaced by the Fuel Pool Cooling and Clean-up system in Units 1 to 3. However, closed loop cooling has not been yet established.
Stagnant water with high levels of radioactivity in the basement of the turbine buildings of Units 1 and 3 is being transferred to the condensers, the radioactive waste treatment facility, the high-temperature incinerator building and temporary storage tanks. Stagnant water in the basement of the turbine building of Unit 6 is being transferred to a temporary tank. Countermeasures against the outflow of water to the sea and to prevent and minimize the dispersion of radionuclides in water have been put in place.
Full-scale spraying of anti-scattering agent is continuing at the site with the use of both conventional and remote controlled equipment.
2. Radiation Monitoring
The daily monitoring of the deposition of caesium and iodine radionuclides for 47 prefectures is continuing. Since 17 May, deposition of I-131 has not been observed. Low levels of Cs-137 deposition were reported in a few prefectures on a few days since 18 May; the reported values range of from 2.2 to 91 Bq/ m2 for Cs-137.
Gamma dose rates values for all 47 prefectures are reported daily by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. On 31 May the gamma dose rate reported for Fukushima prefecture was 1.5 µSv/h. In all other prefectures, reported gamma dose rates were below 0.1 µSv/h; with a general decreasing trend. Meanwhile, the decrease of the gamma dose rate has slowed down, since the short-lived radionuclides have decayed away.
Gamma dose rates reported specifically for the monitoring points in the eastern part of Fukushima prefecture, for distances of more than 30 km from the Fukushima Daiichi plant, showed a general decreasing trend, ranging from 0.1 µSv/h to 17 µSv/h, as reported for 31 May.
On-site measurements at the west gate of the Fukushima Daiichi plant indicate the presence of I-131 and Cs-137 in the air in the close vicinity of the plant (within approximately 1 km). The concentrations in air reported for 29 May were about 3 Bq/m3 for I-131 and about 9 Bq/m3 for Cs-137. The values observed in the previous days show daily fluctuations with an overall decreasing tendency.
Protective Actions
In April, the Government of Japan announced protective actions to reduce the external exposure to the population beyond a distance of 30 km from the Fukushima-Daiichi Nuclear Plant. NISA has reported that the evacuation of the "Planned Evacuation Zones" within Iitate village and Kawamata town commenced on 15 May. Confirmation of completion of the evacuation is awaited.
Food Monitoring and Food Restrictions
Food Monitoring (Reported from 19 to 31 May)
Food monitoring data were reported from 19 to 31 May by the Ministry of Health, Labour and Welfare for a total of 818 samples collected in 18 different prefectures. Most of the monitoring continues to be concentrated in Fukushima prefecture, where 328 out of the 818 samples (over 40%) were collected.
Analytical results for 766 samples (over 93%) of the 818 samples indicated that Cs-134 and Cs-137 or I-131 were either not detected or were below the regulation values set by the Japanese authorities. However, 52 samples were above the regulation values for radioactive caesium and/or iodine.
In Fukushima prefecture, five samples of fishery products collected on 16 and 17 May; one sample of unprocessed tea leaves collected on 17 May; three samples of shiitake mushrooms and nine samples of bamboo shoots collected on 19 May; five samples of seafood collected on 20, 21 and 23 May, and; one sample of Japanese apricot, two samples of shiitake mushrooms and seven samples of bamboo shoots collected on 26 May were above the regulation values for Cs-134/Cs-137. One sample of algae collected on 21 May was also above the regulation values for Cs-134/Cs-137 and I-131.
In Chiba, Gunma, Ibaraki and Tochigi prefectures, eighteen samples of unprocessed raw tea leaves collected on 17, 19, 24 and 26 May were above the regulation values for Cs-134/Cs-137.
Food Restrictions
Consolidated and updated information on food restrictions in Fukushima prefecture were reported on 30 May by the Ministry of Health Labour and Welfare indicating that restrictions on the distribution of bamboo shoots were lifted in the Hirata-Mura area. However, restrictions remain in effect on the distribution of raw unprocessed milk, turnips, bamboo shoots and ostrich fern in specific areas of the prefecture. Restrictions on the distribution and consumption of sand lance fish (the whole prefecture) and specific non-head type (e.g. spinach) and head-type leafy vegetables (e.g. cabbage), flower head brassicas (e.g. broccoli, cauliflower) and shiitake mushrooms (specific areas of the prefecture) also remain in effect.
In Ibaraki prefecture there is a continuing restriction on the distribution of spinach produced in the cities of Kitaibaraki and Takahagi.
3. Marine Monitoring
The marine monitoring programme is carried out both near the discharge areas of the Fukushima Daiichi plant by TEPCO at 22 locations and at off-shore stations by MEXT on 16 stations. The radioactive contamination of the marine environment had occurred by aerial deposition and by continuing discharges and outflow of water with various level of radioactivity from the four damaged reactors at Fukushima Daiichi.
Seawater Monitoring
The activity concentrations of I-131, Cs-134 and Cs-137 in seawater close to the Fukushima Daiichi plant at the screen of Unit 2 have been measured every day since 2 April. Concentrations of Cs-134 and Cs-137 decreased from of more than 100 MBq/L initially to less than 5 kBq/L on 7 May but increased again to levels of around 20 kBq/L at the 16 May and to about 10 kBq/L on the 17 May. Since then the concentrations dropped slowly to less than 2 kBq/L but increased to about 5 kBq/L on 29 May. The levels of I-131 are varying significantly and the activity ratio to radio-caesium is not constant. On 28 and 29 May the concentrations were around 20 kBq/L. The variability of I-131 relatively to the radio-caesium concentrations could be an indication of retention of caesium by the zeolite sandbags in place, which would have almost no effect on iodine or further production of decay products in the reactor.
Monitoring of the marine environment is performed by TEPCO on the near field area and by MEXT at off-shore sampling positions. The monitoring of MEXT includes also measurement of ambient dose rate in air above the sea, analysis of ambient dust above the sea, analysis of surface samples of sea water and analysis of samples of sea water collected at 10 m above the sea bottom and in a mid-layer as well at a few locations for sediments. On most of the offshore stations I-131, Cs-134 and Cs-137 reached levels below the applied detection limit of 10 Bq/L. There will be a further decrease of the concentration during the propagation of contaminated waters in the sea. The activity found in surface sediments at the near shore stations close to the reactors was between 24 and 320 Bq/kg for Cs-137 in the middle of May. The activity in sediments decreases with distance, but is also highly dependent upon the sediment type. The contamination of marine sediments indicates the enrichment of radio-caesium on particulate matter and its removal from the water column into the sea floor.
4. IAEA Activities
The Fact Finding Mission to Japan has now concluded the first part of its work and is on its way back to Vienna. The next part of the work will be to finalize and agree on the report, which will be presented at the Ministerial Conference in June. A preliminary summary is available on the IAEA website.

Summary of Reactor Status (2 June 2011) View more presentations from IAEA

Radiological Monitoring and Consequences of Fukushima Nuclear Accident (2 June 2011)

View more presentations from IAEA

In summary:

Pressure in Reactor 1 primary containment is actually over 1 atmosphere, not 1 atmosphere (or open to air) as claimed by the article posted at top.

A cover is being put on to slow radiation releases, no mention whatsoever of entombment.

No mention whatsoever of radically high (4000 mSv and up) radiation levels.