Normal
Based on the information coming out of TEPCO, it appears that units 1,2 and 3 remain critical but stable. Partial melting has almost certainly occurred in all three cores. There was definitely a period of no water injection because of a pressure buildup caused by stuck relief valve ”” always a potential issue for in high pressure systems. This figure illustrates the current state of play with the reactor units and spent fuel ponds:[ATTACH=full]79470[/ATTACH]The following is the latest status report, with timelines, from the Federation of Electric Power Companies of Japan (FEPC) Washington DC Office.””””””””””– • Radiation Levels o At 6:40AM (JST) on March 16, a radiation level of 400 milli sievert per hour was recorded outside the west side of the secondary containment building of the Unit 3 reactor at Fukushima Daiichi Nuclear Power Station. At 6:40AM on March 16, a radiation level of 100 milli sievert per hour was recorded outside the west side of the secondary containment building of the Unit 4 reactor at Fukushima Daiichi Nuclear Power Station. o At 8:47AM on March 16, a radiation level of 150 milli sievert per hour was recorded outside the secondary containment building of Unit 2 reactor of Fukushima Daiichi Nuclear Power Station. At 8:47AM on March 16, a radiation level of 300 milli sievert per hour was recorded between the exteriors of the secondary containment buildings of Unit 2 reactor and Unit 3 reactor of Fukushima Daiichi Nuclear Power Station. At 8:47AM on March 16, a radiation level of 400 milli sievert per hour was recorded outside the secondary containment building of Unit 3 reactor of Fukushima Daiichi Nuclear Power Station. At 8:47AM on March 16, radiation level of 100 milli sievert per hour was recorded outside the secondary containment building of Unit 4 reactor of Fukushima Daiichi Nuclear Power Station. o At 10:40AM on March 16, a radiation level of 10 milli sievert per hour was recorded at the main gate of the Fukushima Daiichi Nuclear Power Station. o At 4:10PM on March 16, a radiation level of 1530 micro sievert per hour was recorded at the main gate of the Fukushima Daiichi Nuclear Power Station. o For comparison, a human receives 2400 micro sievert per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6900 micro sievert per scan. • Fukushima Daiichi Unit 1 reactor o At 6:55AM on March 16, the pressure inside the reactor core was measured at 0.17 MPa. The water level inside the reactor core was measured at 1.8 meters below the top of the fuel rods. • Fukushima Daiichi Unit 2 reactor o At 6:55AM on March 16, the pressure inside the reactor core was measured at 0.043 MPa. The water level inside the reactor core was measured at 1.4 meters below the top of the fuel rods. • Fukushima Daiichi Unit 3 reactor o At 8:37AM on March 16, white smoke was observed emanating from the vicinity of the secondary containment building. o At 9:55AM on March 16, the pressure inside the reactor core was measured at 0.088 MPa. The water level inside the reactor core was measured at 1.9 meters below the top of the fuel rods. o At 11:32AM on March 16, the Japanese government announced that the possibility of significant damage to the primary containment vessel was low. • Fukushima Daiichi Unit 4 reactor o At 4:08AM on March 15, the temperature of the spent fuel pool was measured at 183 degrees Fahrenheit. o At 5:45AM on March 16, a fire occurred in the vicinity of the third floor of the secondary containment building. o At 7:26AM on March 16, no flames or smoke was observed and thus it was concluded that the fire extinguished on its own accord. • Fukushima Daiichi Unit 5 reactor o At 4:00AM on March 16, the temperature of the spent fuel pool was measured at 141 degrees Fahrenheit. • Fukushima Daiichi Unit 6 reactor o At 4:00AM on March 16, the temperature of the spent fuel pool was measured at 137 degrees Fahrenheit. • Rokkasho Reprocessing Plant and Accompanying Facilities o As of 12:00PM on March 15, power generation of all facilities was restored to the commercial electricity grid from backup power generation systems. It was confirmed that no fire, damage to equipment, injuries to personnel occurred. Radiation levels were measured at a normal level of safety.””””””””””–[ATTACH=full]79471[/ATTACH]Further important information can be read at World Nuclear News, especially Problems for units 3 and 4 and Attempts to refill fuel ponds. Some key extracts:The Japan Atomic Industry Forum reports that the level of water in unit 4′s fuel pond is low and damage to fuel stored there is suspected. Efforts are underway to refill the pool, including an abandoned attempt to douse the building with water from an army helicopter, hoping to get some to go through the damaged building. The temperature of the pond was last known to be 84 ºC on 14 and 15 March, said the International Atomic Energy Agency. There was no data for today…Efforts to cool the partially exposed cores of units 1, 2 and 3 continue. So long as radiological conditions allow, a team of workers pumps seawater into the reactor vessels. This boils away, raising steam pressure which must later be vented. Fuel assemblies are exposed by between one and two metres at the top, but the high thermal conductivity of the zirconium alloy rod casings helps cooling with just the lower portion of the rods submerged. This process is set to continue until the heat produced by the core has reduced so that the entire core can be covered.The lack of recent temperature data may stem from a broken gauge. Please read the above WNN links for further details.In sum, this accident is now significantly more severe than Three Mile Island in 1979. It resulted from a unique combination of failures to plant systems caused by the tsunami, and the broad destruction of infrastructure for water and electricity supply which would normally be reestablished within a day or two following a reactor accident. My initial estimates of the extent of the problem, on March 12, did not anticipate the cascading problems that arose from the extended loss of externally sourced AC power to the site, and my prediction that ‘there is no credible risk of a serious accident‘ has been proven quite wrong as a result. It remains to be seen whether my forecast on the possibility of containment breaches and the very low level of danger to the public as a result of this tragic chain of circumstances will be proven correct. For the sake of the people there, I sure hope it does stand the test of time.
Based on the information coming out of TEPCO, it appears that units 1,2 and 3 remain critical but stable. Partial melting has almost certainly occurred in all three cores. There was definitely a period of no water injection because of a pressure buildup caused by stuck relief valve ”” always a potential issue for in high pressure systems. This figure illustrates the current state of play with the reactor units and spent fuel ponds:
[ATTACH=full]79470[/ATTACH]
The following is the latest status report, with timelines, from the Federation of Electric Power Companies of Japan (FEPC) Washington DC Office.
””””””””””–
• Radiation Levels
o At 6:40AM (JST) on March 16, a radiation level of 400 milli sievert per hour was recorded outside the west side of the secondary containment building of the Unit 3 reactor at Fukushima Daiichi Nuclear Power Station.
At 6:40AM on March 16, a radiation level of 100 milli sievert per hour was recorded outside the west side of the secondary containment building of the Unit 4 reactor at Fukushima Daiichi Nuclear Power Station.
o At 8:47AM on March 16, a radiation level of 150 milli sievert per hour was recorded outside the secondary containment building of Unit 2 reactor of Fukushima Daiichi Nuclear Power Station.
At 8:47AM on March 16, a radiation level of 300 milli sievert per hour was recorded between the exteriors of the secondary containment buildings of Unit 2 reactor and Unit 3 reactor of Fukushima Daiichi Nuclear Power Station.
At 8:47AM on March 16, a radiation level of 400 milli sievert per hour was recorded outside the secondary containment building of Unit 3 reactor of Fukushima Daiichi Nuclear Power Station.
At 8:47AM on March 16, radiation level of 100 milli sievert per hour was recorded outside the secondary containment building of Unit 4 reactor of Fukushima Daiichi Nuclear Power Station.
o At 10:40AM on March 16, a radiation level of 10 milli sievert per hour was recorded at the main gate of the Fukushima Daiichi Nuclear Power Station.
o At 4:10PM on March 16, a radiation level of 1530 micro sievert per hour was recorded at the main gate of the Fukushima Daiichi Nuclear Power Station.
o For comparison, a human receives 2400 micro sievert per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6900 micro sievert per scan.
• Fukushima Daiichi Unit 1 reactor
o At 6:55AM on March 16, the pressure inside the reactor core was measured at 0.17 MPa. The water level inside the reactor core was measured at 1.8 meters below the top of the fuel rods.
• Fukushima Daiichi Unit 2 reactor
o At 6:55AM on March 16, the pressure inside the reactor core was measured at 0.043 MPa. The water level inside the reactor core was measured at 1.4 meters below the top of the fuel rods.
• Fukushima Daiichi Unit 3 reactor
o At 8:37AM on March 16, white smoke was observed emanating from the vicinity of the secondary containment building.
o At 9:55AM on March 16, the pressure inside the reactor core was measured at 0.088 MPa. The water level inside the reactor core was measured at 1.9 meters below the top of the fuel rods.
o At 11:32AM on March 16, the Japanese government announced that the possibility of significant damage to the primary containment vessel was low.
• Fukushima Daiichi Unit 4 reactor
o At 4:08AM on March 15, the temperature of the spent fuel pool was measured at 183 degrees Fahrenheit.
o At 5:45AM on March 16, a fire occurred in the vicinity of the third floor of the secondary containment building.
o At 7:26AM on March 16, no flames or smoke was observed and thus it was concluded that the fire extinguished on its own accord.
• Fukushima Daiichi Unit 5 reactor
o At 4:00AM on March 16, the temperature of the spent fuel pool was measured at 141 degrees Fahrenheit.
• Fukushima Daiichi Unit 6 reactor
o At 4:00AM on March 16, the temperature of the spent fuel pool was measured at 137 degrees Fahrenheit.
• Rokkasho Reprocessing Plant and Accompanying Facilities
o As of 12:00PM on March 15, power generation of all facilities was restored to the commercial electricity grid from backup power generation systems. It was confirmed that no fire, damage to equipment, injuries to personnel occurred. Radiation levels were measured at a normal level of safety.
[ATTACH=full]79471[/ATTACH]Further important information can be read at World Nuclear News, especially Problems for units 3 and 4 and Attempts to refill fuel ponds. Some key extracts:
The Japan Atomic Industry Forum reports that the level of water in unit 4′s fuel pond is low and damage to fuel stored there is suspected. Efforts are underway to refill the pool, including an abandoned attempt to douse the building with water from an army helicopter, hoping to get some to go through the damaged building. The temperature of the pond was last known to be 84 ºC on 14 and 15 March, said the International Atomic Energy Agency. There was no data for today…
Efforts to cool the partially exposed cores of units 1, 2 and 3 continue. So long as radiological conditions allow, a team of workers pumps seawater into the reactor vessels. This boils away, raising steam pressure which must later be vented. Fuel assemblies are exposed by between one and two metres at the top, but the high thermal conductivity of the zirconium alloy rod casings helps cooling with just the lower portion of the rods submerged. This process is set to continue until the heat produced by the core has reduced so that the entire core can be covered.
The lack of recent temperature data may stem from a broken gauge. Please read the above WNN links for further details.
In sum, this accident is now significantly more severe than Three Mile Island in 1979. It resulted from a unique combination of failures to plant systems caused by the tsunami, and the broad destruction of infrastructure for water and electricity supply which would normally be reestablished within a day or two following a reactor accident. My initial estimates of the extent of the problem, on March 12, did not anticipate the cascading problems that arose from the extended loss of externally sourced AC power to the site, and my prediction that ‘there is no credible risk of a serious accident‘ has been proven quite wrong as a result. It remains to be seen whether my forecast on the possibility of containment breaches and the very low level of danger to the public as a result of this tragic chain of circumstances will be proven correct. For the sake of the people there, I sure hope it does stand the test of time.
Hello and welcome to Aussie Stock Forums!
To gain full access you must register. Registration is free and takes only a few seconds to complete.
Already a member? Log in here.
