Normal
Two other useful sources of information are from the WNN: Radiation decreasing, fuel ponds warming and Second fire reported at unit 4. ANS Nuclear Cafe continues to be a great collator of key official channels and top news stories. Finally, this is a useful perspective from an MIT staffer that is well worth reading: What happened at the Fukushima reactor? Events in Japan confirm the robustness of modern nuclear technology ”” not a failure Kirk Sorenson, from Energy from Thorium blog, also has this very interesting piece: Thoughts on Fukushima-Daiichi. A concluding excerpt:What is known is that this is a situation very different than Chernobyl or Three Mile Island. There was no operator error involved at Fukushima-Daiichi, and each reactor was successfully shut down within moments of detecting the quake. The situation has evolved slowly but in a manner that was not anticipated by designers who had not assumed that electrical power to run emergency pumps would be unavailable for days after the shutdown. They built an impressive array of redundant pumps and power generating equipment to preclude against this problem. Unfortunately, the tsunami destroyed it.There are some characteristics of a nuclear fission reactor that will be common to every nuclear fission reactor. They will always have to contend with decay heat. They will always have to produce heat at high temperatures to generate electricity. But they do not have to use coolant fluids like water that must operate at high pressures in order to achieve high temperatures. Other fluids like fluoride salts can operate at high temperatures yet at the same pressures as the outside. Fluoride salts are impervious to radiation damage, unlike water, and don’t evolve hydrogen gas which can lead to an explosion. Solid nuclear fuel like that used at Fukushima-Daiichi can melt and release radioactive materials if not cooled consistently during shutdown. Fluoride salts can carry fuel in chemically-stable forms that can be passively cooled without pumps driven by emergency power generation. There are solutions to the extreme situation that was encountered at Fukushima-Daiichi, and it may be in our best interest to pursue them.More updates as further information comes to hand. Otherwise, for me, it’s back to the mad TV and radio media circus. UPDATE: From World Nuclear News: Problems for units 3 and 4Chief Cabinet Secretary Yukio Edano had outlined problems that had occured on the morning of 16 March with Fukushima Daiichi 3 and 4. At 8:34am local time white smoke was seen billowing out of Fukushima Daiichi 3. Efforts to determine the cause of this development were interrupted as all workers had evacuated to a safe area due to rising radiation readings. Readings from a sensor near the front gate had fluctuated for some time, although Edano said that on the whole there was no health hazard. Earlier in the morning readings had ranged between 600-800 microsieverts per hour, but at 10am readings rose to 1000 microsieverts per hour. Readings began to fall again from around 10:54. Edano said that one possibility being considered was that the unit 3 reactor had suffered a similar failure to that suffered by unit 2 yesterday, although there had been no reported blast or loud sound, which had been the case for unit 2. The immediate focus, said Edano was on monitoring of levels and checking pumping operations. Edano also outlined plans for units 4-6. Preparations were being made to inject water into unit 4, however the high levels of radiation from unit 3 were imparing those preparations. When possible, the water injection would be done gradually as there were safety concerns over pouring a large amount of water at once. The water will be pumped into the reactor building from the ground, plans to drop water from a helicopter having been abandoned. Although he said that “all things were possible” Edano did not believe that recriticality at unit 4 was a realistic risk Second fire at unit 4 Earlier, the Nuclear and Industrial Safety Agency said that a blaze was spotted in the reactor building of Fukushima Daiichi 4 at 5.45am local time this morning. Attempts to extinguish it were reportedly delayed due to high levels of radiation in the area. A spokesperson for TEPCO said that by around 6:15am there were no flames to be seen. The incident at unit 4 is believed to be in the region of a used fuel pond in the upper portion of the reactor building. Origins Tokyo Electric Power Company issued a notice of an explosion at unit 4 at 6am on 15 March. This was followed by the company’s confirmation of damage around the fifth floor rooftop area of the reactor building. On that day, a fire was discovered but investigations concluded it had died down by around 11am. At present it is not clear whether today’s fire was a completely new blaze, or if the fire reported yesterday had flared up again.
Two other useful sources of information are from the WNN: Radiation decreasing, fuel ponds warming and Second fire reported at unit 4. ANS Nuclear Cafe continues to be a great collator of key official channels and top news stories.
Finally, this is a useful perspective from an MIT staffer that is well worth reading:
What happened at the Fukushima reactor? Events in Japan confirm the robustness of modern nuclear technology ”” not a failure
Kirk Sorenson, from Energy from Thorium blog, also has this very interesting piece: Thoughts on Fukushima-Daiichi. A concluding excerpt:
What is known is that this is a situation very different than Chernobyl or Three Mile Island. There was no operator error involved at Fukushima-Daiichi, and each reactor was successfully shut down within moments of detecting the quake. The situation has evolved slowly but in a manner that was not anticipated by designers who had not assumed that electrical power to run emergency pumps would be unavailable for days after the shutdown. They built an impressive array of redundant pumps and power generating equipment to preclude against this problem. Unfortunately, the tsunami destroyed it.
There are some characteristics of a nuclear fission reactor that will be common to every nuclear fission reactor. They will always have to contend with decay heat. They will always have to produce heat at high temperatures to generate electricity. But they do not have to use coolant fluids like water that must operate at high pressures in order to achieve high temperatures. Other fluids like fluoride salts can operate at high temperatures yet at the same pressures as the outside. Fluoride salts are impervious to radiation damage, unlike water, and don’t evolve hydrogen gas which can lead to an explosion. Solid nuclear fuel like that used at Fukushima-Daiichi can melt and release radioactive materials if not cooled consistently during shutdown. Fluoride salts can carry fuel in chemically-stable forms that can be passively cooled without pumps driven by emergency power generation. There are solutions to the extreme situation that was encountered at Fukushima-Daiichi, and it may be in our best interest to pursue them.
More updates as further information comes to hand. Otherwise, for me, it’s back to the mad TV and radio media circus.
UPDATE: From World Nuclear News: Problems for units 3 and 4Chief Cabinet Secretary Yukio Edano had outlined problems that had occured on the morning of 16 March with Fukushima Daiichi 3 and 4.
At 8:34am local time white smoke was seen billowing out of Fukushima Daiichi 3. Efforts to determine the cause of this development were interrupted as all workers had evacuated to a safe area due to rising radiation readings. Readings from a sensor near the front gate had fluctuated for some time, although Edano said that on the whole there was no health hazard. Earlier in the morning readings had ranged between 600-800 microsieverts per hour, but at 10am readings rose to 1000 microsieverts per hour. Readings began to fall again from around 10:54.
Edano said that one possibility being considered was that the unit 3 reactor had suffered a similar failure to that suffered by unit 2 yesterday, although there had been no reported blast or loud sound, which had been the case for unit 2. The immediate focus, said Edano was on monitoring of levels and checking pumping operations.
Edano also outlined plans for units 4-6. Preparations were being made to inject water into unit 4, however the high levels of radiation from unit 3 were imparing those preparations. When possible, the water injection would be done gradually as there were safety concerns over pouring a large amount of water at once. The water will be pumped into the reactor building from the ground, plans to drop water from a helicopter having been abandoned. Although he said that “all things were possible” Edano did not believe that recriticality at unit 4 was a realistic risk
Second fire at unit 4
Earlier, the Nuclear and Industrial Safety Agency said that a blaze was spotted in the reactor building of Fukushima Daiichi 4 at 5.45am local time this morning.
Attempts to extinguish it were reportedly delayed due to high levels of radiation in the area. A spokesperson for TEPCO said that by around 6:15am there were no flames to be seen.
The incident at unit 4 is believed to be in the region of a used fuel pond in the upper portion of the reactor building.
Origins
Tokyo Electric Power Company issued a notice of an explosion at unit 4 at 6am on 15 March. This was followed by the company’s confirmation of damage around the fifth floor rooftop area of the reactor building.
On that day, a fire was discovered but investigations concluded it had died down by around 11am.
At present it is not clear whether today’s fire was a completely new blaze, or if the fire reported yesterday had flared up again.
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