With the Japan thing, what strikes me is the horribly ignorant people they send to cover a nuclear disaster. They need to send more technical people to cover these things, or at least have the stories run by a good technical writer/editor that understands the subject before release. We have been getting basically noise. They were reporting people hospitalized due to radiation including one guy that got hospitalized for a broken arm after a containment explosion. I didn't know radiation broke bones.
beatthesystem
JoinedPosts by beatthesystem
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Question about News Reporters who go to Natural Disasters
by Broken Promises inafter watching news casts on the queensland floods and cyclone, the christchurch earthquake and japan's earthquake and tsunami..... when these reporters go to these areas, do they bring their own food and water?
surely they don't expect to be looked after at these afflicted places?.
does anyone know?.
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Fading When You Move, with a Twist of Lime
by RayPublisher in[if gte mso 9]><xml> <w:worddocument> <w:view>normal</w:view> <w:zoom>0</w:zoom> <w:trackmoves /> <w:trackformatting /> <w:punctuationkerning /> <w:validateagainstschemas /> <w:saveifxmlinvalid>false</w:saveifxmlinvalid> <w:ignoremixedcontent>false</w:ignoremixedcontent> <w:alwaysshowplaceholdertext>false</w:alwaysshowplaceholdertext> <w:donotpromoteqf /> <w:lidthemeother>en-us</w:lidthemeother> <w:lidthemeasian>x-none</w:lidthemeasian> <w:lidthemecomplexscript>x-none</w:lidthemecomplexscript> <w:compatibility> <w:breakwrappedtables /> <w:snaptogridincell /> <w:wraptextwithpunct /> <w:useasianbreakrules /> <w:dontgrowautofit /> <w:splitpgbreakandparamark /> <w:dontvertaligncellwithsp /> <w:dontbreakconstrainedforcedtables /> <w:dontvertalignintxbx /> <w:word11kerningpairs /> <w:cachedcolbalance /> </w:compatibility> <w:browserlevel>microsoftinternetexplorer4</w:browserlevel> <m:mathpr> <m:mathfont m:val="cambria math" /> <m:brkbin m:val="before" /> <m:brkbinsub m:val=" " /> <m:smallfrac m:val="off" /> <m:dispdef /> <m:lmargin m:val="0" /> <m:rmargin m:val="0" /> <m:defjc m:val="centergroup" /> <m:wrapindent m:val="1440" /> <m:intlim m:val="subsup" /> <m:narylim m:val="undovr" /> </m:mathpr></w:worddocument> </xml><!
[endif][if gte mso 10]> <mce:style><!
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beatthesystem
That's pure genius. I did the move-fade, but never thought of hacking the system.
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Ambien vs Temazepam
by ssn587 infriend of mine out west told me his spouse has been having trouble staying asleep with ambien and now she has been prescribed temazepam which they said would make her sleep better and longer.
has anyone out here had those and what is the difference, and do you knjow if the temazepam really works or not?.
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beatthesystem
Ambien does not go well with Jose Cuervo in a hotel room on your birthday.
And it does not mix with a laptop and bandwidth.
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Where to get radiation pills?
by Iamallcool inhttp://www.naturalnews.com/031708_iodine_radiation.html.
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beatthesystem
If you mean potassium iodide, Amazon has plenty of sources.
I'm stocked up. :-)
I've got a CDV-700 geiger counter...
and a CDV-715 site survey meter (not a geiger counter this one uses an ion chamber)
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beatthesystem
Hello Prodigal Son.
It's only "pseudoscience" because it is SUPPRESSED by the SELFISH ELITE
Do you mean the same selfish elites that allow those websites you link to, to stay up?
Hydrogen powered cars are real. However, WHERE does the hydrogen come from? Like I said, hydrogen is a form of energy storage, not energy production. Think of a hydrogen tank in a car as being the equivalent of a battery. A battery needs to be charged from a power source for a car to run. It is not in and of itself a power source, it is a storage medium. A hydrogen tank needs to be supplied with hydrogen, which is also created from a power source. This is usually water, which needs to be "cracked," generally using electrolysis. You get less energy out than you put in, however, not much different from a battery.
Regarding "free energy", we have not yet demonstrated such an energy source in science. Please produced peer reviewed papers, and I will consider it.
You are linking to some quack inventions on water powered cars.
Here is a wiki page on it, doubtless edited by the selfish elites:
http://en.wikipedia.org/wiki/Water-fuelled_car
This article focuses on vehicles that claim to extract chemical potential energy directly from water. Water is fully oxidized hydrogen. Hydrogen itself is a high-energy, flammable substance, but its useful energy is released when water is formed—water will not burn. The process of electrolysis, discussed below, would split water into hydrogen and oxygen, but it takes as much energy to take apart a water molecule as was released when the hydrogen was oxidized to form water. In fact, some energy would be lost in converting water to hydrogen and then burning the hydrogen because some heat would always be produced in the conversions. Releasing chemical energy from water would therefore violate the first and/or second laws of thermodynamics. [5] [6] [7] [8]
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beatthesystem
i.e Tesla "free energy"
Sorry to disagree, but this is pseudoscience. There is no "free energy", at least that has been discovered by science. I recommend you read up on the laws of thermodynamics.
hydrogen
Unless we mine the atmosphere of Jupiter, hydrogen is an energy storage medium, not an energy generation one. There is almost no free hydrogen on earth. It is nearly all locked up in strong chemical bonds with other elements.
water power
We are using almost all available sources of hydro power as is. There is very little room for increased production in developed countries, and no where near what is needed to replace nuclear or coal.
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beatthesystem
We don't have much of a choice, if we desire to continue to receive the benefits of electricity without spewing carbon into the atmosphere. Even in Japan's case, we are dealing with early generation reactor designs that are over 40 years old and were not designed to take the seismic hit these have taken (followed by an epic tsunami), and it seems that the situation will be contained, and the radiation released will not be disastrous.
New reactor designs have far greater passive safety.
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Why you should not worry about Japan's nuclear reactor problems.
by beatthesystem ina nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods.
so if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all.
when the uranium splits, it generates a neutron (see above).
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beatthesystem
A bit more info for those that are interested:
http://cdrsalamander.blogspot.com/2011/03/american-nuclear-society-backgrounder.html
Monday, March 14, 2011
American Nuclear Society Backgrounder on Japan
Below is some outstanding information from the American Nuclear Society on the Japanese nuclear challenges. Excellent reading.American Nuclear Society Backgrounder:
Japanese Earthquake/Tsunami; Problems with Nuclear Reactors
3/12/2011 5:22 PM EST
To begin, a sense of perspective is needed… right now, the Japanese earthquake/tsunami is clearly a catastrophe; the situation at impacted nuclear reactors is, in the words of IAEA, an "Accident with Local Consequences."
The Japanese earthquake and tsunami are natural catastrophes of historic proportions. The death toll is likely to be in the thousands. While the information is still not complete at this time, the tragic loss of life and destruction caused by the earthquake and tsunami will likely dwarf the damage caused by the problems associated with the impacted Japanese nuclear plants.
What happened?
Recognizing that information is still not complete due to the destruction of the communication infrastructure, producing reports that are conflicting, here is our best understanding of the sequence of events at the Fukushima I-1 power station.- The plant was immediately shut down (scrammed) when the earthquake first hit. The automatic power system worked.
- All external power to the station was lost when the sea water swept away the power lines.
- Diesel generators started to provide backup electrical power to the plant’s backup cooling system. The backup worked.
- The diesel generators ceased functioning after approximately one hour due to tsunami induced damage, reportedly to their fuel supply.
- An Isolation condenser was used to remove the decay heat from the shutdown reactor.
- Apparently the plant then experienced a small loss of coolant from the reactor.
- Reactor Core Isolation Cooling (RCIC) pumps, which operate on steam from the reactor, were used to replace reactor core water inventory, however, the battery-supplied control valves lost DC power after the prolonged use.
- DC power from batteries was consumed after approximately 8 hours.
- At that point, the plant experienced a complete blackout (no electric power at all).
- Hours passed as primary water inventory was lost and core degradation occurred (through some combination of zirconium oxidation and clad failure).
- Portable diesel generators were delivered to the plant site.
- AC power was restored allowing for a different backup pumping system to replace inventory in reactor pressure vessel (RPV).
- Pressure in the containment drywell rose as wetwell became hotter.
- The Drywell containment was vented to outside reactor building which surrounds the containment.
- Hydrogen produced from zirconium oxidation was vented from the containment into the reactor building.
- Hydrogen in reactor building exploded causing it to collapse around the containment.
- The containment around the reactor and RPV were reported to be intact.
- The decision was made to inject seawater into the RPV to continue to the cooling process, another backup system that was designed into the plant from inception.
- Radioactivity releases from operator initiated venting appear to be decreasing.
Can it happen here in the US?- While there are risks associated with operating nuclear plants and other industrial facilities, the chances of an adverse event similar to what happened in Japan occurring in the US is small.
- Since September 11, 2001, additional safeguards and training have been put in place at US nuclear reactors which allow plant operators to cool the reactor core during an extended power outage and/or failure of backup generators – “blackout conditions.”
Is a nuclear reactor "meltdown" a catastrophic event?- Not necessarily. Nuclear reactors are built with redundant safety systems. Even if the fuel in the reactor melts, the reactor's containment systems are designed to prevent the spread of radioactivity into the environment. Should an event like this occur, containing the radioactive materials could actually be considered a "success" given the scale of this natural disaster that had not been considered in the original design. The nuclear power industry will learn from this event, and redesign our facilities as needed to make them safer in the future.
What is the ANS doing?
ANS has reached out to The Atomic Energy Society of Japan (AESJ) to offer technical assistance.
ANS has established an incident communications response team. This team has compiling relevant news reports and other publicly available information on the ANS blog, which can be found atansnuclearcafe.org.
The team is also fielding media inquiries and providing reporters with background information and technical perspective as the events unfold. Finally, the ANS is collecting information from publicly available sources, our sources in government
agencies, and our sources on the ground in Japan, to better understand the extent and impact of the incident. -
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Why you should not worry about Japan's nuclear reactor problems.
by beatthesystem ina nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods.
so if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all.
when the uranium splits, it generates a neutron (see above).
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beatthesystem
http://www.informationdissemination.net/2011/03/new-york-times-us-navy-helicopter.html
Monday, March 14, 2011
New York Times: US Navy Helicopter Exposed to Radiation
This almost sounds scary, but I have a feeling that when the details omitted in the article emerge from the Navy it will not be as scary as the New York Times article suggests.
The Pentagon was expected to announce that the aircraft carrier Ronald Reagan, which is sailing in the Pacific, passed through a radioactive cloud from stricken nuclear reactors in Japan, causing crew members on deck to receive a month’s worth of radiation in about an hour, government officials said Sunday.
The key detail missing in all of these stories is the levels of radiation being detected measured in micro sievert (mSv). Instead of using the popular media comparison of average over a year, lets use the example of a CT scan which runs about 2,000 - 2,200 micro sieverts in one use.
The officials added that American helicopters flying missions about 60 miles north of the damaged reactors became coated with particulate radiation that had to be washed off.
As best we have been informed to date, the radiation levels at the Fukushima power plant run about 100 to 1,200 microsieverts per hour, and have peaked around the time of the explosions. While you can read the New York Times article and be alarmed, I actually quoted the safety measure necessary for this radiation exposure from the article - wash it off.
According to various news reports, the maximum level detected so far around the Fukushima plant is 1,557.5 micro sievert logged Sunday. In the open atmosphere, this number would drop considerably due to disipation. We will likely learn details of the Navy exposure and remedy taken, and I do think the Navy will take an abundance of caution, but if the Navy is smart they will also use this opportunity to educate regarding nuclear power - since the Navy is an organization with many thousands of nuclear specialists.
The New York Times article goes on to say this:The plume issue has arisen before. In 1986, radiation spewing from the Chernobyl disaster in Ukraine was spread around the globe on winds and reached the West Coast in 10 days. It was judged more of a curiosity than a threat.
The comparison to Chernobyl remains popular, but is also good way to identify if someone talking about Fukushima knows what they hell they are talking about. If someone suggests any comparison between the two based on the current data, they are an idiot - not an expert.
Here is how to put Fukushima in the context of Chernobyl. The radiation levels at Chernobyl were of the order of 30,000 roentgens per hour near the plant.
30,000 roentgens is 3,579 sieverts. One million micro sieverts to one sievert. Doing a little quick math, if we are comparing the magnitude of radiation levels coming from 'meltdown' at the Fukushima power plant to the 'meltdown' at Chernobyl we get 1 / 3,579,000
Again, doing the math, a relative comparison suggests Fukushima is 0.00002% of the Chernobyl levels of radiation. These 'meltdowns' have nothing in common, unless you believe .000002% - below the mSv of a CT scan - is a public health threat.
For the record, 7th Fleet is repositioning ships after the contamination detection. This is a wise precaution, because as many have pointed out, it is one thing to trust the Japanese numbers but it is more important to verify them.
Updated :
The New York Times has already followed up with another article on the topic. 17 Navy personnel were exposed to radiation according to the report.Cmdr. Jeff A. Davis, a spokesman for the American Seventh Fleet in Japan, said the Navy personnel — who apparently had flown through a radioactive plume from a damaged nuclear power plant — had been ordered to dispose of their uniforms and to undergo a decontamination scrub that had successfully removed radioactive particles.
Like I said, the Navy will take an abundance of caution dealing with this issue. You do not discuss nuclear power without also discussing safety. I also note that on the nuclear powered USS Ronald Reagan (CVN 76), the detection systems for radiation are very good.
“They received very, very low levels of contamination,” Commander Davis said in a telephone interview from Japan early Monday.
“It certainly is not cause for alarm,” he said. “It is something we have to watch very carefully and make sure we are able to monitor, and to mitigate against this environmental hazard.”
I once read an article that suggested the US Navy has more nuclear trained engineers than the Department of Energy. I don't know if that is actually true, but I do know that there are probably hundreds of nuclear trained US Navy readers who visit here daily and if I get something wrong regarding nuclear issues - I am going to get a hurricane of email and comments that will highlight my mistakes. -
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Why you should not worry about Japan's nuclear reactor problems.
by beatthesystem ina nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods.
so if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all.
when the uranium splits, it generates a neutron (see above).
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beatthesystem
Fukushima Nuclear Accident – a simple and accurate explanation
Along with reliable sources such as the IAEA and WNN updates, there is an incredible amount of misinformation and hyperbole flying around the internet and media right now about the Fukushima nuclear reactor situation. In the BNC post Discussion Thread – Japanese nuclear reactors and the 11 March 2011 earthquake (and in the many comments that attend the top post), a lot of technical detail is provided, as well as regular updates. But what about a layman’s summary? How do most people get a grasp on what is happening, why, and what the consequences will be?
Below I reproduce a summary on the situation prepared by Dr Josef Oehmen, a research scientist at MIT, in Boston. He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry. This was first posted by Jason Morgan earlier this evening, and he has kindly allowed me to reproduce it here. I think it is very important that this information be widely understood.
I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.
We will have to cover some fundamentals, before we get into what is going on.
Construction of the Fukushima nuclear power plants
The plants at Fukushima are so called Boiling Water Reactors, or BWR for short. Boiling Water Reactors are similar to a pressure cooker. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water send back to be heated by the nuclear fuel. The pressure cooker operates at about 250 °C.
The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 3000 °C. The fuel is manufactured in pellets (think little cylinders the size of Lego bricks). Those pieces are then put into a long tube made of Zircaloy with a melting point of 2200 °C, and sealed tight. The assembly is called a fuel rod. These fuel rods are then put together to form larger packages, and a number of these packages are then put into the reactor. All these packages together are referred to as “the core”.
The Zircaloy casing is the first containment. It separates the radioactive fuel from the rest of the world.
The core is then placed in the “pressure vessels”. That is the pressure cooker we talked about before. The pressure vessels is the second containment. This is one sturdy piece of a pot, designed to safely contain the core for temperatures several hundred °C. That covers the scenarios where cooling can be restored at some point.
The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. For that purpose, a large and thick concrete basin is cast under the pressure vessel (the second containment), which is filled with graphite, all inside the third containment. This is the so-called “core catcher”. If the core melts and the pressure vessel bursts (and eventually melts), it will catch the molten fuel and everything else. It is built in such a way that the nuclear fuel will be spread out, so it can cool down.
This third containment is then surrounded by the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosion, but more to that later).
Fundamentals of nuclear reactions
The uranium fuel generates heat by nuclear fission. Big uranium atoms are split into smaller atoms. That generates heat plus neutrons (one of the particles that forms an atom). When the neutron hits another uranium atom, that splits, generating more neutrons and so on. That is called the nuclear chain reaction.
Now, just packing a lot of fuel rods next to each other would quickly lead to overheating and after about 45 minutes to a melting of the fuel rods. It is worth mentioning at this point that the nuclear fuel in a reactor can *never* cause a nuclear explosion the type of a nuclear bomb. Building a nuclear bomb is actually quite difficult (ask Iran). In Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all containments, propelling molten core material into the environment (a “dirty bomb”). Why that did not and will not happen in Japan, further below.
In order to control the nuclear chain reaction, the reactor operators use so-called “moderator rods”. The moderator rods absorb the neutrons and kill the chain reaction instantaneously. A nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods. The coolant water then takes away the heat (and converts it into steam and electricity) at the same rate as the core produces it. And you have a lot of leeway around the standard operating point of 250°C.
The challenge is that after inserting the rods and stopping the chain reaction, the core still keeps producing heat. The uranium “stopped” the chain reaction. But a number of intermediate radioactive elements are created by the uranium during its fission process, most notably Cesium and Iodine isotopes, i.e. radioactive versions of these elements that will eventually split up into smaller atoms and not be radioactive anymore. Those elements keep decaying and producing heat. Because they are not regenerated any longer from the uranium (the uranium stopped decaying after the moderator rods were put in), they get less and less, and so the core cools down over a matter of days, until those intermediate radioactive elements are used up.
This residual heat is causing the headaches right now.
So the first “type” of radioactive material is the uranium in the fuel rods, plus the intermediate radioactive elements that the uranium splits into, also inside the fuel rod (Cesium and Iodine).
There is a second type of radioactive material created, outside the fuel rods. The big main difference up front: Those radioactive materials have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements. Those radioactive elements are N-16, the radioactive isotope (or version) of nitrogen (air). The others are noble gases such as Xenon. But where do they come from? When the uranium splits, it generates a neutron (see above). Most of these neutrons will hit other uranium atoms and keep the nuclear chain reaction going. But some will leave the fuel rod and hit the water molecules, or the air that is in the water. Then, a non-radioactive element can “capture” the neutron. It becomes radioactive. As described above, it will quickly (seconds) get rid again of the neutron to return to its former beautiful self.
This second “type” of radiation is very important when we talk about the radioactivity being released into the environment later on.
What happened at Fukushima
I will try to summarize the main facts. The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; the difference between the 8.2 that the plants were built for and the 8.9 that happened is 7 times, not 0.7). So the first hooray for Japanese engineering, everything held up.
When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. Within seconds after the earthquake started, the moderator rods had been inserted into the core and nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions.
The earthquake destroyed the external power supply of the nuclear reactor. That is one of the most serious accidents for a nuclear power plant, and accordingly, a “plant black out” receives a lot of attention when designing backup systems. The power is needed to keep the coolant pumps working. Since the power plant had been shut down, it cannot produce any electricity by itself any more.
Things were going well for an hour. One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Then the Tsunami came, much bigger than people had expected when building the power plant (see above, factor 7). The tsunami took out all multiple sets of backup Diesel generators.
When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, moderator rods in our out, core molten or not, inside the reactor.
When the diesel generators were gone, the reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.
Within the 8 hours, another power source had to be found and connected to the power plant. The power grid was down due to the earthquake. The diesel generators were destroyed by the tsunami. So mobile diesel generators were trucked in.
This is where things started to go seriously wrong. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.
At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event”. It is again a step along the “Depth of Defense” lines. The power to the cooling systems should never have failed completely, but it did, so they “retreat” to the next line of defense. All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator, right through to managing a core meltdown.
It was at this stage that people started to talk about core meltdown. Because at the end of the day, if cooling cannot be restored, the core will eventually melt (after hours or days), and the last line of defense, the core catcher and third containment, would come into play.
But the goal at this stage was to manage the core while it was heating up, and ensure that the first containment (the Zircaloy tubes that contains the nuclear fuel), as well as the second containment (our pressure cooker) remain intact and operational for as long as possible, to give the engineers time to fix the cooling systems.
Because cooling the core is such a big deal, the reactor has a number of cooling systems, each in multiple versions (the reactor water cleanup system, the decay heat removal, the reactor core isolating cooling, the standby liquid cooling system, and the emergency core cooling system). Which one failed when or did not fail is not clear at this point in time.
So imagine our pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The priority now is to maintain integrity of the first containment (keep temperature of the fuel rods below 2200°C), as well as the second containment, the pressure cooker. In order to maintain integrity of the pressure cooker (the second containment), the pressure has to be released from time to time. Because the ability to do that in an emergency is so important, the reactor has 11 pressure release valves. The operators now started venting steam from time to time to control the pressure. The temperature at this stage was about 550°C.
This is when the reports about “radiation leakage” starting coming in. I believe I explained above why venting the steam is theoretically the same as releasing radiation into the environment, but why it was and is not dangerous. The radioactive nitrogen as well as the noble gases do not pose a threat to human health.
At some stage during this venting, the explosion occurred. The explosion took place outside of the third containment (our “last line of defense”), and the reactor building. Remember that the reactor building has no function in keeping the radioactivity contained. It is not entirely clear yet what has happened, but this is the likely scenario: The operators decided to vent the steam from the pressure vessel not directly into the environment, but into the space between the third containment and the reactor building (to give the radioactivity in the steam more time to subside). The problem is that at the high temperatures that the core had reached at this stage, water molecules can “disassociate” into oxygen and hydrogen – an explosive mixture. And it did explode, outside the third containment, damaging the reactor building around. It was that sort of explosion, but inside the pressure vessel (because it was badly designed and not managed properly by the operators) that lead to the explosion of Chernobyl. This was never a risk at Fukushima. The problem of hydrogen-oxygen formation is one of the biggies when you design a power plant (if you are not Soviet, that is), so the reactor is build and operated in a way it cannot happen inside the containment. It happened outside, which was not intended but a possible scenario and OK, because it did not pose a risk for the containment.
So the pressure was under control, as steam was vented. Now, if you keep boiling your pot, the problem is that the water level will keep falling and falling. The core is covered by several meters of water in order to allow for some time to pass (hours, days) before it gets exposed. Once the rods start to be exposed at the top, the exposed parts will reach the critical temperature of 2200 °C after about 45 minutes. This is when the first containment, the Zircaloy tube, would fail.
And this started to happen. The cooling could not be restored before there was some (very limited, but still) damage to the casing of some of the fuel. The nuclear material itself was still intact, but the surrounding Zircaloy shell had started melting. What happened now is that some of the byproducts of the uranium decay – radioactive Cesium and Iodine – started to mix with the steam. The big problem, uranium, was still under control, because the uranium oxide rods were good until 3000 °C. It is confirmed that a very small amount of Cesium and Iodine was measured in the steam that was released into the atmosphere.
It seems this was the “go signal” for a major plan B. The small amounts of Cesium that were measured told the operators that the first containment on one of the rods somewhere was about to give. The Plan A had been to restore one of the regular cooling systems to the core. Why that failed is unclear. One plausible explanation is that the tsunami also took away / polluted all the clean water needed for the regular cooling systems.
The water used in the cooling system is very clean, demineralized (like distilled) water. The reason to use pure water is the above mentioned activation by the neutrons from the Uranium: Pure water does not get activated much, so stays practically radioactive-free. Dirt or salt in the water will absorb the neutrons quicker, becoming more radioactive. This has no effect whatsoever on the core – it does not care what it is cooled by. But it makes life more difficult for the operators and mechanics when they have to deal with activated (i.e. slightly radioactive) water.
But Plan A had failed – cooling systems down or additional clean water unavailable – so Plan B came into effect. This is what it looks like happened:
In order to prevent a core meltdown, the operators started to use sea water to cool the core. I am not quite sure if they flooded our pressure cooker with it (the second containment), or if they flooded the third containment, immersing the pressure cooker. But that is not relevant for us.
The point is that the nuclear fuel has now been cooled down. Because the chain reaction has been stopped a long time ago, there is only very little residual heat being produced now. The large amount of cooling water that has been used is sufficient to take up that heat. Because it is a lot of water, the core does not produce sufficient heat any more to produce any significant pressure. Also, boric acid has been added to the seawater. Boric acid is “liquid control rod”. Whatever decay is still going on, the Boron will capture the neutrons and further speed up the cooling down of the core.
The plant came close to a core meltdown. Here is the worst-case scenario that was avoided: If the seawater could not have been used for treatment, the operators would have continued to vent the water steam to avoid pressure buildup. The third containment would then have been completely sealed to allow the core meltdown to happen without releasing radioactive material. After the meltdown, there would have been a waiting period for the intermediate radioactive materials to decay inside the reactor, and all radioactive particles to settle on a surface inside the containment. The cooling system would have been restored eventually, and the molten core cooled to a manageable temperature. The containment would have been cleaned up on the inside. Then a messy job of removing the molten core from the containment would have begun, packing the (now solid again) fuel bit by bit into transportation containers to be shipped to processing plants. Depending on the damage, the block of the plant would then either be repaired or dismantled.
Now, where does that leave us?
- The plant is safe now and will stay safe.
- Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.
- Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.
- There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage.
- The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the “main” nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago. This further reduces the activation. The bottom line is that there will be some low level of activation of the seawater, which will also be removed by the treatment facilities.
- The seawater will then be replaced over time with the “normal” cooling water
- The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.
- Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.
- The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)
- I believe the most significant problem will be a prolonged power shortage. About half of Japan’s nuclear reactors will probably have to be inspected, reducing the nation’s power generating capacity by 15%. This will probably be covered by running gas power plants that are usually only used for peak loads to cover some of the base load as well. That will increase your electricity bill, as well as lead to potential power shortages during peak demand, in Japan.
