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Originally posted by THEDUDE86
This is a load of speculation and crap...I work for an emergency management agency in a state with many nuclear facilities. Our facility was federally funded after sept 11 and has several different emergency related agencies including military...I cant say exact amount nuclear plants,because then you could find out where I work. We have a command center that is for the nuclear power plants located in my building. This facility has devices throughout the state and country that can detect radioactive particles in the atmosphere. Now, I am allowed in this area, but friday the area was on full lock down and they brought in security and nuclear commission people. Now this facility would only be activated given a threat to the united states of a radiological event. There is also a secure room that was I am never allowed in was also busy. This room has secure phone lines to Washington.
My building is one of the safest buildings in the Midwest. It is protected from gamma radiation with a metal mesh around the building. I'm not trying to stir up something here but the only time I see this room activated is for training exercises and they train on nuclear winter, nuclear meltdown that results in releases, and even strong solar flare activity. All this seems interesting to me that things were activated he because of japan. That much I do know because one of my coworkers who is a earthquake expert was called in to the area to talk about the type of quake
Originally posted by BobbyTarass
You should rename you thread as "OMG ! STUNNING NEWS, NUCLEAR FALSE FLAG, THE SHOCKING LIE ! JOURNALIST CONSPIRACY".
Then you'll get something like 100+ S&F and people would read your paper.
When you're posting on ATS, quit trying to be reasonnable, people here only listen to fearmongers, they'll tell you that they do not want the worse to happen and thus try to prevent it by acting like it's already happening but don't fall for it, those guys have a hard-on everytime the earth cough.
Originally posted by THEDUDE86
This is a load of speculation and crap...I work for an emergency management agency in a state with many nuclear facilities. Our facility was federally funded after sept 11 and has several different emergency related agencies including military...I cant say exact amount nuclear plants,because then you could find out where I work. We have a command center that is for the nuclear power plants located in my building. This facility has devices throughout the state and country that can detect radioactive particles in the atmosphere. Now, I am allowed in this area, but friday the area was on full lock down and they brought in security and nuclear commission people. Now this facility would only be activated given a threat to the united states of a radiological event. There is also a secure room that was I am never allowed in was also busy. This room has secure phone lines to Washington.
My building is one of the safest buildings in the Midwest. It is protected from gamma radiation with a metal mesh around the building. I'm not trying to stir up something here but the only time I see this room activated is for training exercises and they train on nuclear winter, nuclear meltdown that results in releases, and even strong solar flare activity. All this seems interesting to me that things were activated he because of japan. That much I do know because one of my coworkers who is a earthquake expert was called in to the area to talk about the type of quake
I repeat, there was and will *not* be any significant release of radioactivity from the damaged Japanese reactors.
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.
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.
***UPDATE – 3/14 8:15 pm EST***
Units 1 and 3 are currently in a stable condition according to TEPCO press releases, but the extent of the fuel damage is unknown. That said, radiation levels at the Fukushima plant have fallen to 231 micro sieverts (23.1 millirem) as of 2:30 pm March 14th (local time).
***UPDATE – 3/14 10:55 pm EST***
The details about what happened at the Unit 2 reactor are still being determined. The post on what is happening at the Unit 2 reactor contains more up-to-date information. Radiation levels have increased, but to what level remains unknown.
Since the reactor’s cooling capability was limited, and the water inventory in the reactor was decreasing, engineers decided to inject sea water (mixed with boric acid – a neutron absorber) to ensure the rods remain covered with water. Although the reactor had been shut down, boric acid is added as a conservative measure to ensure the reactor stays shut down. Boric acid is also capable of trapping some of the remaining iodine in the water so that it cannot escape, however this trapping is not the primary function of the boric acid.
The water used in the cooling system is purified, demineralized water. The reason to use pure water is to limit the corrosion potential of the coolant water during normal operation. Injecting seawater will require more cleanup after the event, but provided cooling at the time.
This process decreased the temperature of the fuel rods to a non-damaging level. Because the reactor had been shut down a long time ago, the decay heat had decreased to a significantly lower level, so the pressure in the plant stabilized, and venting was no longer required.
News Updates and Current Status of Facilities
Posted on March 16, 2011 10:59 am UTC by mitnse
Units 1 and 2: TEPCO has released estimates of the levels of core damage at these two reactors: 70% damage at Unit 1 and 33% at Unit 2. They have also stated that Unit 1 is being adequately cooled.
Outlook: It is difficult to make conjectures at this point about the final disposition of the damaged fuel without further information. However, during our only operating experience with a partially melted and subsequently cooled core, Three Mile Island, the fuel mass was fully contained by the reactor vessel, resulting in minimal radiation release to the public. A decision is currently being made on how to best supply cooling water to Unit 2.
Unit 3: At 8:34 AM JST, white smoke was seen billowing from the roof of Unit 3. The source of this smoke was not investigated because workers were evacuated due to radiation levels. These levels had been fluctuating during the early morning hours before rising to 300-400 millisievert/hr around the time that the smoke appeared. It was unclear at the time whether these rising levels were a result of some new event at Unit 3, or were lingering as a result of Unit 2’s recent troubles.
Outlook: In order to provide some perspective on worker doses to this point, radiation sickness sets in at roughly 1000 millisieverts. A future post will deal further with the health effects of various amounts of radiation. Response to the smoke seen at Unit 3 appears to be in an information gathering phase at this point. Chief Cabinet Secretary Yukio Edano speculated that the smoke from Unit 3 might be the result of a similar wetwell explosion to that at Unit 2, but there is not enough information currently available to support or refute that statement.
Units 4-6: Flames at Unit 4 were reported to be the result of a pump fire, which caused a small explosion that damaged the roof of Unit 4 (See TEPCO’s press release on the most recent fire at www.tepco.co.jp...) . Efforts at Units 4-6 are focused on supplying cooling water to the spent fuel storage pools. Temperatures in these pools began to rise in the days after the quake. At the time of the quake, only Unit 4’s core had been fully offloaded to the spent fuel pool for maintenance; roughly 1/3 of the cores of Units 5 and 6 had been offloaded. This explains in part why the temperature in Unit 4’s pool has risen faster than at the other reactors: it has a higher inventory, both in fuel volume and in heat load.
Outlook: The fuel within these pools needs to remain covered with cooling water in order to prevent the low levels of decay heat present from causing it to melt, and also in order to provide shielding. Boiling of the water results in reduction of the water level in the pools, so if/when the pools get hot enough for boiling to begin, water needs to be added to replace what boils off. The staff of Unit 4 plan to begin pumping water to the spent fuel pool from ground level as soon as radiation levels from Unit 3 are low enough for them to return. This pumping operation should be relatively easier than injection of cooling water into the reactor vessels at Units 1-3 because the pools are at atmospheric pressure.
Sources: TEPCO, World Nuclear News
UPDATE (11:48 AM EST): A report by the Federation of Electric Power Companies of Japan indicates that radiation levels as a result of the Unit 4 fire were higher than those reported previously. Radiation levels early this morning at the outside of Unit 3 measured at 400 millisieverts/hr. At the present time however, radiation levels at the boundary of the facility are 1530 microsieverts/hour. We will continue to update as further reliable information is available.