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Fukushima Explosion Update: Core Presumed Intact As Sea Water Used To Bring Temperature Down, Radiation Level At 1015 Microsieverts/Hour
The damage control to the Fukushima explosion reported earlier is coming fast and furious. According to CNN, "the explosion at an earthquake-damaged nuclear plant was not caused by
damage to the nuclear reactor but by a pumping system that failed as
crews tried to bring the reactor's temperature down, Chief Cabinet
Secretary Yukio Edano said Saturday. The next step for workers at the Fukushima Daiichi plant will be to
flood the reactor containment structure with sea water to bring the
reactor's temperature down to safe levels, he said. The effort is
expected to take two days." While the government is trying to play down the threat from the explosion, it has nonetheless double the evacuation zone radius from 10 to 20 kilometers: "Radiation levels have fallen since the explosion and there is no
immediate danger, Edano said. But authorities were nevertheless
expanding the evacuation to include a radius of 20 kilometers (about
12.5 miles) around the plant. The evacuation previously reached out to
10 kilometers." Next steps are to flood the reactor with salt water. NHK reports: "The
TEPCO Fukushima Daiichi nuclear power plant in Fukushima Prefecture is
believed to be exploded, and in order to prevent corruption, the
containment vessel will be filled with sea water to cool containers and
vehicles used by the SDF pump I. According to the Ministry of Defense,
work will begin at 8:00 pm, and that it expected to end around 1:00 am
on March 13 (or roughly 11 am Eastern)." And while containment efforts peak, the radiation level is reported to be in the range of 1015 microsieverts / hr. In the meantime, confusion in Japan is pervasive as up to a million people are without power. And while we hope the outcome of the Fukushima situation will be prompt and favorable, the economic devastation to the country will be pervasive for weeks to come.
CNN reports:
More damage control:
Radiation levels have fallen since the explosion and there is no immediate danger, Edano said. But authorities were nevertheless expanding the evacuation to include a radius of 20 kilometers (about 12.5 miles) around the plant. The evacuation previously reached out to 10 kilometers.
The explosion about 3:30 p.m. Saturday sent white smoke rising above the plant a day after a massive earthquake and tsunami crippled cooling systems at the plant in northeastern Japan. Four workers were injured in the blast.
The walls of a concrete building surrounding the reactor container collapsed, but the reactor and its containment system were not damaged in the explosion, Edano said.
Before Edano's announcement, Malcolm Grimston, associate fellow for energy, environment and development at London's Chatham House, said the explosion indicated that "it's clearly a serious situation, but that in itself does not necessarily mean major (nuclear) contamination."
Japanese public broadcaster NHK said the injured workers were in the process of cooling a nuclear reactor at the plant by injecting water into its core.
The Fukushima prefecture government said hourly radiation levels at the plant had reached levels allowable for ordinary people over the course of a year, Kyodo reported.
Earlier Saturday, Japan's nuclear agency said workers were continuing efforts to cool fuel rods at the plant after a small amount of radioactive material escaped into the air.
The agency said there was a strong possibility that the radioactive cesium monitors detected was from the melting of a fuel rod at the plant, adding that engineers were continuing to cool the fuel rods by pumping water around them.
Cesium is a byproduct of the nuclear fission process that occurs in nuclear plants.
A spokesman for Japan's Nuclear and Industrial Agency earlier said atomic material had seeped out of one of the five nuclear reactors at the Daiichi plant, located about 160 miles (260 kilometers) north of Tokyo.
"This is a situation that has the potential for a nuclear catastrophe. It's basically a race against time, because what has happened is that plant operators have not been able to cool down the core of at least two reactors," said Robert Alvarez, a senior scholar at the Institute for Policy Studies in Washington.
Alert.net quotes Chernobyl veterans who are scrambling to calm the public that this will not be a repeat of the Prypiat disaster:
Experts said pictures of mist above the plant suggested only small amounts of radiation had been expelled as part of measures to ensure its stability, far from the radioactive clouds that Chernobyl spewed out when it exploded in 1986.
"The explosion at No. 1 generating set of the Fukushima nuclear plant in Japan, which took place today, will not be a repetition of the Chernobyl nuclear disaster," said Valeriy Hlyhalo, deputy director of the Chernobyl nuclear safety centre.
He was quoted by Interfax news agency as saying Japanese reactors were better protected than Chernobyl, where just over 30 firefighters were killed in the explosion. The world's worst civilian nuclear disaster, Chernobyl has also been blamed for thousands of deaths due to radiation-linked illness.
"Apart from that, these reactors are designed to work at a high seismicity zone, although what has happened is beyond the impact the plants were designed to withstand," Hlyhalo said.
"Therefore, the consequences should not be as serious as after the Chernobyl nuclear disaster."
We will continue following what appears to be nothing but a prolonged attempt at disaster spin as earthquake aftershocks continue.
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(Mar 13,2011)
Impact to TEPCO's Facilities due to Miyagiken-Oki Earthquake (as of 8AM)
Below is major impact to TEPCO's facilities due to the Miyagiken-Oki Earthquake that occurred yesterday at 2:46PM. *new items are underlined [Nuclear Power Station] Fukushima Daiichi Nuclear Power Station: Units 1 to 3: shutdown due to earthquake Units 4 to 6: outage due to regular inspection * The national government has instructed evacuation for those local residents within 20km radius of the site periphery. * The value of radioactive material (iodine, etc) is increasing according to the monitoring car at the site (outside of the site). One of the monitoring posts is also indicating higher than normal level. * Since the amount of radiation at the boundary of the site exceeds the limits, we decide at 4:17PM, Mar 12 and we have reported and/or noticed the government agencies concerned to apply the clause 1 of the Article 15 of the Radiation Disaster Measure at 5PM, Mar 12. * In addition, a vertical earthquake hit the site and big explosion has happened near the Unit 1 and smoke breaks out around 3:36PM, Mar 12th. * We started injection of sea water into the reactor core of Unit 1 at 8:20PM, Mar 12 and then boric acid subsequently. * High Pressure Coolant Injection System of Unit 3 automatically stopped. We endeavored to restart the Reactor Core Isolation Cooling System but failed. Also, we could not confirm the water inflow of Emergency Core Cooling System. As such, we decided at 5.10AM, Mar 12, and we reported and/or noticed the government agencies concerned to apply the clause 1 of the Article 15 of the Radiation Disaster Measure at 5:58AM, Mar 13. In order to fully secure safety, we operated the vent valve to reduce the pressure of the reactor containment vessels (partial release of air containing radioactive materials) and completed the procedure at 8:41AM, Mar 13, * We continue endeavoring to secure the safety that all we can do and monitoring the periphery. Fukushima Daini Nuclear Power Station: Units 1 to 4: shutdown due to earthquake * The national government has instructed evacuation for those local residents within 10km radius of the periphery. * At present, we have decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. These measures are considered to be implemented in Units 1, 2 and 3 and accordingly, we have reported and/or noticed the government agencies concerned. * Unit 3 has been stopped and being "nuclear reactor cooling hot stop" at 12:15PM. * The operator trapped in the crane operating console of the exhaust stack was transferred to the ground at 5:13PM and confirmed the death at 5:17PM. Kashiwazaki Kariwa Nuclear Power Station: Units 1, 5, 6, 7: normal operation Units 2 to 4: outage due to regular inspection [Thermal Power Station] Hirono Thermal Power Station Units 2 and 4: shutdown due to earthquake Hitachinaka Thermal Power Station Unit 1: shutdown due to earthquake Kashima Thermal Power Station Units 2, 3, 5, 6: shutdown due to earthquake Ohi Thermal Power Station Units 2, 3: shutdown due to earthquake Higashi-Ohgishima Thermal Power Station Unit 1: shutdown due to earthquake [Hydro Power Station] * All the stations have been restored. [Transmission System, etc.] 4 substations shown below have been shutdown: - Naka Substation - Shin Motegi Substation - Joban Substation - Ibaraki Substation - Nishi Mito Substation [Blackout in TEPCO's Service Area] Total of about 0.31 million households are out of power. Tokyo: 0 Kanagawa Pref.: 0 Tochigi Pref.: 7,221 Chiba Pref.: 301 Saitama Pref: 0 Gunma Pref.: 0 Ibaraki Pref: 298,977 Yamanashi Pref: 0 Shizuoka Pref: 0 (east of Fuji River) [Supply and Demand Status within TEPCO's Service Area to Secure Stable Power Supply] Backup supply from Shinshinano Conversion Station: 600MW Backup supply from Sakuma Conversion Station: 300MW Backup supply from Higashi Shimizu Conversion Station: 100MW Because TEPCO's facilities have been seriously damaged, power shortage may occur. TEPCO appreciates customers' cooperation in reducing electricity usage by avoiding using unnecessary lighting and electrical equipment.Failure of Unit #3 RCIC was known and reported by AP,Reuters, et al.
Does anyone have a link or account of the air releases (amount, duration etc.)???
I can't find anyone state side from Bechtel, etc. that has the inside track. If anyone is reading this and they are monitoring a live text feed or have real-time data from the Utility please reach out to me: aucanary@gmail.com. If any of the nuke ops guys on here are from Hatch or another similar BWR I would like to get your thoughts on Unit 3. Worrisome on this one? I am trying to dig up an old drawing stick from Hatch -- both are Mark 1 correct?
During TMI (which was a B&W not a GE reactor) we had P&IDs (I was at Midland, bwah!, at the time - same type of unit as TMI). We gat faxed plume maps from the NRC and monitored the releases (at least the containment air pressure relief). I don't think anyone will ever know what exactly went into the river.
These units are toasted. IMO Unit 3 may get the Boron next. Unit 1 has already been poisoned. Only Ben and Tim could nuke this much cash in a weekend.
I was involved in some redesign work and did outages at Cooper Nuclear in Nebraska, it is the same type reactor as the Japanese unit in question. The best way to get the plume maps and other associated detailed data is from the license applications, which is public info here in the US, not sure about Japan.
I'm not sure what to make of Unit 3 or for that matter Unit 1 or any of their Units. RCIC should be basically a single terry turbine that doesn't require ac power, at least at the BWR I work at that has RCIC. Could be different in their design. Older BWR's, pre BWR/4 don't have RCIC but may have emergency isolation condensers that automatically cool Rx steam but use either service water or Rx Bldg Closed Loop Cooling water - I forget which. The Cesium angle is interesting as the levels are what will matter...there is a small amount of radio Cesium in the cooling water from minor leakers that may exist (or existed in the past). So its not out of the question that some Cesium could be detected externally post-venting without there being fuel damage. The H2 buildup still puzzles me. There are charcoal filter trains that are designed to trap and filter gas & particulate that is radioactive...allowing time for decay before venting to atmosphere. Not sure if this system blew up or a general buildup in the Rx Bldg. Not having RCIC...assumedly they have nothing else but the TEPCO reports aren't clear as to exact system status. Like do they have ac power connected to emergency buses or not.
"RCIC should be basically a single terry turbine that doesn't require ac power"
I think that I read somewhere of a failure of their DC system. DC control power is required for speed control. Remember, HPCI starts slow, and ramps up with increased signal - whereas RCIC starts at 100% and waits for oil pressure to build to the point where the electric speed control signal can be processed.
Oh, and the HPCI turbine usually has a DC oil pump - no battery - no HPCI.
This is sounding "badder and badder". Like you said, for all EDG's to fail, now that's a bad day. Sustained LOOP - not fun.
I wonder if the design bases took into account the seismic (X/Y/Z axis) acceleration, but forgot the possibility of flooding due to a tsunami?
I think our RCIC turbine has a mechanical ballhead governor that doesn't require dc or ac power. However, what I'm not recalling, is how the steam supply gets established or valves open to inject...could be Air Operated Valves that fail open (which I think is the case) though if MOV's are used, then some sort of power is needed. Seems unlikely that they would have lost dc right away...though I'm hesistant to assume anything isn't possible at this point.
The Woodward governor uses iol pressure from the shaft-driven oil pump. The ball-head device is actually an overspeed device. That is what I was alluding to. If you dodn't have a DC control signal, when the RCIC turbine received its start signal, it has the potential to overspeed. That is why most procedures will have the speed set ran back to an arbitrary range of about 2,000 R.P.M. in case it does get started from a core isolation signal. That speed also is about the minimum where the oil pump can produce enough pressure to move the governor valve.
Some early BWR's had AOV's but due to concerns over the temperatures reached in the ECCS injection room, others later changed to DC MOV's. These can be manually opened by declutching the motor and having at the handwheel (LimiTorque brand). The AC MOV's were used as IRC isolations (induction motor = no sparking brushes).
Anyway - it really looks bad. This is the type of scenario you see on your annual graded excercise - and mumble about how it could never get this bad (so many emergency systems not available). Now, I know better.
"Only Ben and Tim could nuke this much cash in a weekend." LOL. Somebody else mentioned it - Quantitative Radiation...
Unit 3 could sit and control Rx pressure via SRV's for quite a while...but eventually you have to vent the drywell to keep it w/in pressure limits, which it sounds like they are doing just that. I am still mystified as to exactly what is preventing so many emergency ac systems from (apparently) functioning. I saw a blog linked earlier that listed the worst hit site as having 13 EDG's - all of which failed w/in 1 hour. What? That's a disturbing stat if true. And it might be as most of the plants are having problems of some sort. I'm eventually going to have a sh*tstorm to evaluate for our site when details are put out. Like why have so many diesels or emergency power systems failed? I fear they relied on more cross-Unit sharing of ac power than what we would typically see here but that's speculation.
If anyone is interested in the various failure scenarios and mitigation methods, this OECD document is pretty easy reading and is pretty informative.
http://www.oecd-nea.org/nsd/docs/2000/csni-r2000-9.pdf
It seems that the IAEA has not picked up on Unit 3's condition as reported by TEPCO. Interesting.
Another thing to consider, if indeed the primary/secondary containment is intact and not leaking, and yet hydrogen emanating from the core leaked into the building during a vent operation, then obviously the vent piping is compromised. If that is the case, then the HEPA/carbon filters designed to catch radioactive particulate matter during vents would not be 100% design effective.
LOL ... well... lets see they're using condensate make up (seawater) to recirc into the unit - through what LPCI? RHR (probably) FW lines? MS shutoff are closed so where is all that crapped up water going? I can't believe that the Radwaste facility can handle the amounts of liquid on hand.
As for the air releases -- HEPA filter to amos? Bwah! Your kidding right? That's why they should be putting out plume maps every 10 minutes.
They could sell those units to China for scrap metal. Japanese version of Cash-for-Clunkers.
During TMI I told my girlfreind to get a bag packed and be prepared to drive south on 95 out of the D.C. area. The internals of the TMI reactor were destroyed (I mean rubble) -- took a long time and a lot of special tools to get the crap out, so the DOE could have the reactor in pieces (for metalurgy tests?)
I just don't think we have gone that far on this one yet, but I could be wrong. And, you are right in that they can probably only be circulating water if they are doing a system tie and dumping it in the ocean, either that are they are doing a static recap to keep the water above the rods as it evaporates.....not a good thing if the heat flux is still high or the partial melt is supporting fission (likely). They may be venting to atmosphere directly, but if so, they are damn sure not admitting it!
Actually, the remnants of TMI did undergo extensive testing to determine the effects of neutron flux on components during a graded accident. Kind of a "quick" aging test:)
The nucular industry is about to come undone.
In addition, the Japanese government had been repeatedly warned about seismic risks:
sending a team of Lawyers and will bury your azzes..This is criminal in its scope.
The nucular [sic] industry is about to come undone.
Don't think so. Japan must have nuclear power, they have no other choice.
Hopefully this will spur modernization, 4th generation reactors, thorium, etc.