This is another clearinghouse diary for discussion and commentary about the ongoing nuclear disaster(s) in Japan. For updated information on news and a timeline of the events following the March 11 Japanese Earthquake, visit the Mothership. The Mothership is updated regularly and also provides a more extensive list of news and data sources, social media, crisis mapping and other relevant information.
If you would like to recommend this diary feel free to do so. All previous liveblogs published to the Japan Nuclear Incident group can be found here. The group also serves as an archive for Coverage@Kos.
The"ROV" (a Remote Operating Vehicle) is a 'child diary' for liveblog coverage of major breaking news stories. (The term was borrowed from the Gulf Watchers coverage of the Deep Water Horizon crisis.)
Given the seriousness of this situation, please use this diary for posting information DIRECTLY Related to coverage of the developing news!
To continue following and participating in the breaking coverage in Japan Nuclear Incidents series, click here and then click the heart icon underneath the profile picture to the Right. This will bring these diaries directly into your personal "stream."
Latest April 7 Japan NHK Feed:
Injection of nitrogen gas into the containment vessel of the No.1 reactor expected to continue for six days. Nitrogen is being used to prevent another hydrogen explosion. gas is being used to prevent a hydrogen blast at the reactor. TEPCO considering similar injections at No. 2 and 3 reactors.
NISA warns injections could result in leakage of radioactive substances outside containment vessels.
Nuclear experts suggest Japan revise evacuation advisories based upon radioactive conditions in the area surrounding Fukushima Daiichi nuclear power plant.
Latest Statistics: Dead: 12,596. 14,747 still missing. The number of dead or missing now exceeds 27,000.
h/t siri
copy of RST Assessment
Status excerpts: Core is contained in the RPV, water level unknown. The sea water left enough salt to fill the lower plenum to the core plate. Current freshwater injections do not contain boron. Recirculation pump seals have likely failed. Assume RHR is not available.
Assessment: Damaged fuel may have slumped to the bottom of the core and fuel in the lower region of the core is likely encased in salt and core flow is severely restricted and likely blocked. The core spray nozzles are likely salted up restricting core spray flow. Injecting fresh water through the feedwater system is cooling the vessel but limited if any flow past the fuel. GE believes that water flow, if not blocked, should be filling the annulus region of the vessel to 2/3 core height. There is likely no water level inside the core barrel. Natural circulation believed impeded by core damage. It is difficult to determine how much cooling is getting to the fuel. Vessel Temperature readings are likely metal temperature with lags actual conditions.
The fuel pool is slowly heating and has not reached saturation. Overhead photos (on 3/19) show entire fuel floor covered by grey-brown debris of building roof.
The primary containment is not damaged.
Of note in the later pages: The pieces of fuel ejected from the SFP were from either 3 or 4. They're not sure. The neutron beams 1km away from the plant were an indicator of this.
Assessments of other reactors below fold....
h/t procrastinator john
Aerial view of an artificial floating island called the ''megafloat'' off the port of Shimizu in Shizuoka. Tokyo Electric Power Co. is considering using a ''megafloat'' to store tainted water with high levels of radiation found at the troubled Fukushima Daiichi nuclear power plant. (Kyodo)
h/t there but for fortune
LA Times: 15 million gallons radioactive water already accumulated
Japanese officials estimate that they already have accumulated about 15 million gallons of highly radioactive water. Hundreds of thousands of gallons are being added every day as the plant's operator, the Tokyo Electric Power Co., continues to feed coolant into the leaky structures.
h/t peraspera
Employee at troubled nuke plant mum about own radiation exposure
A Tokyo Electric Power Co. employee refused in a recent interview to reveal how much radiation he has been exposed to during nearly a month dealing with Japan's worst ever nuclear crisis inside the Fukushima Daiichi nuclear power complex.
''I can't tell you. It's private information as well,'' said Yasuki Murata, a 44-year-old TEPCO worker from the planning and public relations section for the plant, batting away repeated questions about the extent of his radiation exposure in a telephone interview Wednesday with Kyodo News.
h/t dnpvd0111
Core of Reactor Probably Leaked
WASHINGTON — The United States Nuclear Regulatory Commission said Wednesday that some of the core of a stricken Japanese reactor had probably leaked from its steel pressure vessel into the bottom of the containment structure, implying that the damage was even worse than previously thought.
Coverage@Kos: 4/04 - 4/05
HEARTBREAKING Video SOS from Japanese mayor near Fukushima: Near starvation by HamdenRice on 4/4
Fukushima Status Update 4/4 by Kbman on 4/4
Fukushima Update: Fresh Concerns Abound by Akmk on 4/5
Fukushima: Greenpeace Monitors Japan: Evacuate! By radical def on 4/5
One Fish, Two Fish, Radioactive Fish, New Fish
by Brian Ross on 4/5
Please visit ROV #41 for coverage from 4/3 through 4/5 and the archives in Japan Nuclear Incident group for all previous ROVs and Coverage@Kos.
More Below the Fold...
h/t Siri
Reactor #2 - Excerpts from status, entire assessment. See the document linked above for the recommendations
#2
Status excerpts: Core is contained in the reactor pressure vessel, reactor water level is unknown.
Fresh water with boric acid injection...gives temps...Recirculation pump seals have likely failed.
Primary Containment Damage suspected
SFP is covered. Temp at 52C
Assessment: Damaged fuel may have slumped to the bottom of the core and fuel in the lower region of the core is likely encased in salt, however, the amount of salt build-up appears to be less than U-1 based on the reported lower temperatures. Core flow capability is in jeopardy due to continued salt build up.
Injecting water through the RHR system is cooling the vessel, but with limited flow past the fuel. Water flow, if not blocked, should be filling the annulus region of the vessel to 2/3 core height. Based on the reports of RPV level at one half core height, the reactor vessel water level is believed to be even with the level of the recirculation pump seals, implying the seals have failed. While core flow capability may be affected due to continued salt build up, RPV water level indication is suspect due to environment. Natural circulation believed impeded by core damage. It is difficult to determine how much cooling is getting to the fuel. Vessel temperature readings are likely metal temperature which lags actual conditions.
Low level release path: fuel damaged, reactor coolant system potentially breached at recirculation pump seals, primary containment damaged resulting in low level release.
There may be some scrubbing of release if the release path is through the torus and water level is maintained in the torus.
Fuel pool is heating up but is adequately cooled
h/t Siri #3
Core is contained in reactor vessel, water level unknown. Recirculation pump seals have likely failed. Primary Containment: NISA and TEPCO say “damage suspected, JAIF says it’s “not damaged”.
Low water level in the SPF, spraying and pumping sea water into the SFP via the Cooling and purification Line
Assessment:
Damaged fuel may have slumped to the bottom of the core and fuel in the lower region of the core is likely encased in salt, however, the amount of salt build-up appears to be less than U-1, based on the reported lower temperatures. Core flow capability is in jeopardy due to continued salt build up.
Injecting water through the RHR system is cooling the vessel, but with limited flow past the fuel. Water flow if not blocked, should be filling the annulus region of the vessel to 2/3 core height. Based on the reports of RPV level at one half core height, the reactor vessel water level is believed to be even with the level of the recirculation pump seals, implying the seals have failed.
While core flow capability may be affected due to continued salt build up, RPV water level indication is suspect due to environment. Natural circulation believed impeded by core damage. It is difficult to determine how much cooling is getting to the fuel. Vessel temperature readings are likely metal temperature which lags actual conditions.
Low level release path: fuel damaged, reactor coolant system potentially breached at recirculation pump seals, primary containment damaged resulting in low level release. There may be some scrubbing of the release if the release path is through the torus and water level is maintained in the torus.
Fuel pool is heating up but is adequately cooled, and fuel may have been ejected from the pool (based on information from TEPCO of neutron sources found up to 1 mile from the units, and very high dose rate material that had to be bulldozed over between Units 3 and 4). It is also possible the material could have come from Unit 4. Unit 3 turbine basement has flooded. Samples of water indicate some RCS fluid is present (TEPCO sample table – 3/25/11). Several possible sources (MSIV leakage, FW check valves, Rx building sump drains) were identified, however the likely source is the fire water spray onto the reactor building. Additional evaluation is needed.
#4
SFP Status: Low water level, spraying with sea water, hydrogen from the fuel pool exploded, fuel pool is cool heating up very slowly. Temperature is unknown.
Given the amount of decay heat in the fuel in the pool, it is likely that in the days immediately following the accident, the fuel was partially uncovered. The lack of cooling resulted in zirconium water reaction and a release of hydrogen. The hydrogen exploded and damaged secondary containment. The zirconium water reaction could have continued, resulting in a major source term release.
Fuel particulates may have been ejected from the pool (based on information of neutron emitters found up to 1 mile from the units, and very high dose rate material that had to be bulldozed over between Units 3 and 4. It is also possible the material could have come from Unit 3)
In terms of recommendations, under 1 through 3 it says to follow the guidelines of SAMG-1 Primary Containment Flooding, Leg RC/F4 and asks if they can restore and hold RPV injection rate above the Minimum Debris Retention Injection Rate.
See the Document for the listed recommendations for each reactor.
Regularly Updated Data Sources
@Kos: A database of temperature, pressure, radiation levels, etc readings over time can be found in: The Daiichi Database This is an evolving diary that will be updated regularly.
• Japanese Atomic Industrial Forum (JAIF)
• RSOS Emergency & Disaster information Services - Japan
• Daily Telephone Media Briefings from Union of Concerned Scientists
• Energy.gov: The Situation in Japan
• EPA RadNet Map View & EPA's Radiation Air Monitoring
Scribble Live
• Fukushima Data Page: Data for all 3 reactors, as well as a good chunk of data over time: pressure, water flow, core nozzle temp, core bottom temp
• Japan Municipal Water Charts (in Japanese)
Best News Sources
Kyodo Nuclear News Feed
NHK Japan Live
OilDrum: Fukushima Open Thread - Tue 3/29
Asahi on Facebook
Tepco's webcam
Reuters
Fukushima Wikispaces
Bloggers for Japan
Google Earth Engine (download required): Radiation Over Japan. Visit Pachube for mapping.
Rules of the Road
Due to extensive coverage, Coverage@KOS is including diaries covering two-day periods. All coverage is then archived to the group page.
You can assist us in including relevant diaries by providing links to any postings we may have missed to insure they are included in this coverage. Also, note below if diaries are being reposted to other groups so we can direct readers there as well.
Please be kind to kossacks with bandwidth issues. Please do not post images or videos. Again, many thanks for this.
Remember when posting to the thread: STICK TO THE FACTS. Source and link all new information. (This includes insuring authenticity of twitter sources.) Both the Mothership and the ROVs are for reporting and discussing the developing news. Neither space is for opinions or for editorializing on the subject of nuclear energy.
Follow the Japan Nuclear Incident group for 24/7 coverage. Click on heart next to the group name to follow. After following the group, you can access coverage through your personal stream. To join the group, send an email (sidebar to the right).