Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Pseudoscience-is-malarkey on 28/03/2021 23:08:03
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What kind of oversites can cause a nuclear power plant to melt down?
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What kind of oversites can cause a nuclear power plant to melt down?
https://en.wikipedia.org/wiki/Nuclear_meltdown#:~:text=A%20meltdown%20may%20be%20caused,core%2C%20leading%20to%20a%20meltdown.
''A meltdown may be caused by a loss of coolant, loss of coolant pressure, or low coolant flow rate or be the result of a criticality excursion in which the reactor is operated at a power level that exceeds its design limits. Alternatively, an external fire may endanger the core, leading to a meltdown.''
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Hi there @Pseudoscience-is-malarkey
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Nice nickname.
👍
The first & foremost thing that comes to mind is " Human Error " !
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Structural & Designing Faults.
Incapability of handling Complex Operations.
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Probable Sabotage & personal envy or even just getting up on the wrong side of the bed.
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P.S. - Prapz B.C. would have answered sayin ' Uranium ' & ' Plutonium '...
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he hee heeh!
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"What usually causes nucular power plant meltdowns?"
Nothing.
That's why they don't "usually" happen.
They are actually very rare.
Wiki records just 3 major ones and another score of minor ones.
Since 8 of those were in Russian subs, you can draw your own conclusion about "what causes meltdowns".
https://en.wikipedia.org/wiki/Nuclear_and_radiation_accidents_and_incidents#Nuclear_meltdown
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Loss of coolant in a properly-working reactor. Sabotage at Chernobyl.
The human error in the case of Fukushima was siting the plant near the sea in an area subject to tsunami.
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The human error in the case of Fukushima...
There were a few errors that contributed to this...
- No big earthquakes had been recorded in this area for hundreds of years, so obviously, no more would occur for hundreds of years (the opposite is true; when a fault-line is "stuck" for hundreds of years, it is building up pressure for a really big one!)
- Ignoring geologists who pointed to sediments well inland, suggesting that there were very big earthquakes in this region, hundreds of years ago.
- Locating the emergency generators in the basement (where they got flooded), instead of on higher floors (where they could have provided power to keep the coolant circulating in the reactor core).
Isn't 20/20 hindsight wonderful!
In the end, around 16,000 people were killed by the Earthquake and Tsunami.
- It is estimated that less than 10 people may be killed by the reactor meltdown - and these deaths will occur over the next 40 years.
See: https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami
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A meltdown is the overheating of the fuel so it melts down from solid in the reactor, overheating is caused by the heat being generated not being lost.
As you can imagine the build up of heat is because of numerous reasons. Chernobyl was caused by the design of the reactor being a positive coefficient design.
https://en.m.wikipedia.org/wiki/Void_coefficient
Fukushima was a loss of pumping and 3 mile Island a loss of coolant. Windscale is not considered a meltdown as the fuel was not the type of modern design, even though it did melt.
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these days the chances of a nuclear powerplant melt down is close to negligible, unless there is a natural disaster, like in Fukushima Japan
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Chernobyl was caused by the design of the reactor being a positive coefficient design.
That in itself is not a problem. RBMK reactors are relatively simple and generally problem-free as long as you read the handbook. Trouble with Chernobyl 4 was that the operators decided to ignore the BIG RED WARNING in the book, and drove it into a known unstable condition. The exercise was executed as planned, so this was not a matter of "pilot error" but must be seen as deliberate sabotage. That's the problem with the laws of physics - they always win.
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The exercise was executed as planned, so this was not a matter of "pilot error" but must be seen as deliberate sabotage.
No.
Because sabotage has some sort of point to it- financial, political whatever.
They just screwed up. But there is a reason for that.
The German military command told their troops that Enigma was uncrackable. The troops believed them and got "sloppy"- which is how Enigma was cracked.
The Designers said the Titanic was unsinkable, so the captain didn't prioritise the lookouts.
So nobody saw the iceberg until it was too late.
The managers of the space shuttle project thought that the risk of failure was "One in a million"- and they still thought that after the first failure...
The guys running Chernobyl had been told "RBMK reactors are relatively simple and generally problem-free ". or as they put it "safe as a samovar".
We know what happened next...
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I disagree. They had all read the book which clearly set out the correct procedure for shutting down with part-spent fuel, and the reasons for not doing what they did. This was not sloppy execution of a routine shut-down but a planned and deliberate exploration of a forbidden part of the operating envelope. The point was to see if time could be saved by cutting a corner that had been thoroughly researched by the designers.
"Safe as a samovar" has some resonance. Way back in the 1950s my father attended a course on nuclear reactors for the Central Electricity Generating Board. His summary was "a very complicated way to boil water."
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Chernobyl was caused by the design of the reactor being a positive coefficient design.
That in itself is not a problem. RBMK reactors are relatively simple and generally problem-free as long as you read the handbook. Trouble with Chernobyl 4 was that the operators decided to ignore the BIG RED WARNING in the book, and drove it into a known unstable condition. The exercise was executed as planned, so this was not a matter of "pilot error" but must be seen as deliberate sabotage. That's the problem with the laws of physics - they always win.
I can't really argue as many ran out their life times such as chernobyl other reactors, but the fellow in the TV series thought so, he was persecuted for speaking out.
The trouble is there appears to be no failsafe, why did Fukushima fail? Chernobyl surely should have had an off button, the withdrawal of moderators under their own impetus should be designed in, with any residual heat acceptable. Perhaps an emergency gravity fed water tank/ radiator cooling system ? They could have done this at Fukushima but didn't.
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The 737MAX has a failsafe which has so far killed 346 people who would have completed their journeys safely without it.
The shutdown sequence for the RBMK reactor has worked every time. Problem with Chernobyl is that the operators were experimenting with a "home-made" emergency procedure (using the residual momentum of the generators and pumps to close down the system without using the backups) that was strictly forbidden in the manual.
Fukushima was correctly designed to withstand the "100 year" tsunami but not the 1000 year beast that killed it. To do so would have made the design uneconomic. Part of the problem is one of public perception: "reactors are dangerous so must be sited on the coast" or "humans cannot be trusted to fly airplanes".
The Chernobyl TV series was superb, and can be summed up in a single phrase: Kruger and Dunning meet Stanley Milgram.
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Chernobyl surely should have had an off button
All power reactors have an "off" button, which stops the nuclear chain reaction.
However, the residual heat continues to produce around 6-7% of the reactor's output power, even after the fuel rods are fully inserted. This drops below 1% after a day or so.
- This is still enough to cause a meltdown if cooling is not maintained.
- Some of the more modern reactor designs support fully passive cooling, driven by the residual heat
- Reactors of Fukushima and earlier generations require external power to maintain coolant circulation, even after the reactor is shut down.
See: https://en.wikipedia.org/wiki/Decay_heat
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Chernobyl surely should have had an off button
All power reactors have an "off" button, which stops the nuclear chain reaction.
However, the residual heat continues to produce around 6-7% of the reactor's output power, even after the fuel rods are fully inserted. This drops below 1% after a day or so.
- This is still enough to cause a meltdown if cooling is not maintained.
- Some of the more modern reactor designs support fully passive cooling, driven by the residual heat
- Reactors of Fukushima and earlier generations require external power to maintain coolant circulation, even after the reactor is shut down.
See: https://en.wikipedia.org/wiki/Decay_heat
Is this the fundamental problem with nuclear power stations which operate on the "fission" principle.
"Fission" involves the artificial and unnatural splitting of atoms of heavy elements such as Uranium. Thereby releasing neutrons. And once the neutrons get released, they fly out to split other Uranium atoms, in an ultra-fast unstoppable chain-reaction which spreads in microseconds through the whole pile of Uranium
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Resulting in the Uranium pile either detonating instantly in a devastating explosion, or simmering and festering in a slower but lethal radiation-emitting "melt-down", the effects of which go on for years or centuries
Whereas - if you had a nuclear-fusion power station, it would need a constant input of energy from the outside, to keep fusing or squeezing the atoms together.
The energy from the outside would come from an electric current. So if you wanted to shut down the fusion-station, you'd cut off the current by simply pulling out the plug.
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Fukushima was correctly designed to withstand the "100 year" tsunami but not the 1000 year beast that killed it.
With pumps situated on the floor. D'oh.
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Chernobyl surely should have had an off button
All power reactors have an "off" button, which stops the nuclear chain reaction.
However, the residual heat continues to produce around 6-7% of the reactor's output power, even after the fuel rods are fully inserted. This drops below 1% after a day or so.
Chernobyl off button was what killed it, the quick insertion of the control rods blew it up, because they had a moderator at the end. Steam pockets ensued and not a good outcome!
If I (being very careful of the language I use, nuclear reactors and explosions I'm sure flag up at gchq) rendered a reactor incapable of being controlled by consoles, could I cut a rope to drop the control rods? If one control rod jammed could I drop the rest? Would the reactor have passive cooling capability? A clever design in pipework(s) to a radiator(s) radiator on the roof(s) would be good. Nuclear reactors seem not to have the aarospace standard of duplicates and triplicate.
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to shut down the fusion-station, you'd cut off the current by simply pulling out the plug.
It has been argued that controlled nuclear fusion (if/when we ever get it to work) would be safer than fission reactors.
- Partly because the amount of fuel in a fusion reactor at any one time might be 1 gram, rather than 700 tons for a fission reactor.
- But the fuel in a fusion reactor is incredibly hot, and with an uncontrolled shutdown could burn a hole in the wall, requiring tricky repairs before the reactor could be restarted
- most fusion reactor designs use Deuterium+Tritium fuel; this reaction does produce high-energy neutrons, and the walls would become radioactive
an ultra-fast unstoppable chain-reaction which spreads in microseconds through the whole pile of Uranium
As you correctly suggest, this is a description of a fission bomb.
simmering and festering in a slower but lethal radiation-emitting "melt-down"
Unlike your implication, in a fission power reactor:
- The chain reaction is stoppable, using control rods
- A melt-down is not inevitable, provided the fuel temperature is kept below the design limits
Fortunately, most nuclear power reactors are operated properly, most of the time.
- It's the exceptions that produce headlines and exclusion zones...
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"Fission" involves the artificial and unnatural splitting of atoms of heavy elements such as Uranium.
Why do you think it is unnatural?
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
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Chernobyl surely should have had an off button
All power reactors have an "off" button, which stops the nuclear chain reaction.
However, the residual heat continues to produce around 6-7% of the reactor's output power, even after the fuel rods are fully inserted. This drops below 1% after a day or so.
Chernobyl off button was what killed it, the quick insertion of the control rods blew it up, because they had a moderator at the end. Steam pockets ensued and not a good outcome!
If I (being very careful of the language I use, nuclear reactors and explosions I'm sure flag up at gchq) rendered a reactor incapable of being controlled by consoles, could I cut a rope to drop the control rods? If one control rod jammed could I drop the rest? Would the reactor have passive cooling capability? A clever design in pipework(s) to a radiator(s) radiator on the roof(s) would be good. Nuclear reactors seem not to have the aarospace standard of duplicates and triplicate.
They had triplicate systems.
They failed to take account of "common mode failure".
All three cooling systems were washed out at once by a single common cause.
It would also have washed the radiators off the roof..
So a quadruplicate system may not have worked any better.
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The 737MAX has a failsafe which has so far killed 346 people who would have completed their journeys safely without it.
The shutdown sequence for the RBMK reactor has worked every time. Problem with Chernobyl is that the operators were experimenting with a "home-made" emergency procedure (using the residual momentum of the generators and pumps to close down the system without using the backups) that was strictly forbidden in the manual.
Fukushima was correctly designed to withstand the "100 year" tsunami but not the 1000 year beast that killed it. To do so would have made the design uneconomic. Part of the problem is one of public perception: "reactors are dangerous so must be sited on the coast" or "humans cannot be trusted to fly airplanes".
There's always a long list of reasons why any particular thing fails. And with hindsight they're nearly always obvious. But that doesn't stop them happening. With a properly trained crew, the 737Max flights could have been saved; failure of the tail actuator- there's procedure for that which could have worked; it just wasn't in the 737 manual any more, it had been removed.
Among other issues with your analysis, all conventional nuclear reactors need a large water source for cooling. Reactors are often placed on the coast because that's a good source of water.
If you only design for a hundred year event, and there's several hundred reactors, then if your estimate is accurate (they're usually very conservative), that's more than one failure per year.
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You design each station for the 100 or 1000 year event at that site. AFAIK that does not include tsunamis on the UK or French coasts.
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The 737MAX has a failsafe which has so far killed 346 people who would have completed their journeys safely without it.
The shutdown sequence for the RBMK reactor has worked every time. Problem with Chernobyl is that the operators were experimenting with a "home-made" emergency procedure (using the residual momentum of the generators and pumps to close down the system without using the backups) that was strictly forbidden in the manual.
Fukushima was correctly designed to withstand the "100 year" tsunami but not the 1000 year beast that killed it. To do so would have made the design uneconomic. Part of the problem is one of public perception: "reactors are dangerous so must be sited on the coast" or "humans cannot be trusted to fly airplanes".
There's always a long list of reasons why any particular thing fails. And with hindsight they're nearly always obvious. But that doesn't stop them happening. With a properly trained crew, the 737Max flights could have been saved; failure of the tail actuator- there's procedure for that which could have worked; it just wasn't in the 737 manual any more, it had been removed.
Among other issues with your analysis, all conventional nuclear reactors need a large water source for cooling. Reactors are often placed on the coast because that's a good source of water.
If you only design for a hundred year event, and there's several hundred reactors, then if your estimate is accurate (they're usually very conservative), that's more than one failure per year.
If we'd followed some advice, we'd never have allowed steam-engines, because their boilers occasionally blow up.
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With a properly trained crew, the 737Max flights could have been saved;
The MCAS was introduced to remove the need for specific type training for 737-rated pilots. When I bought my first glider I was warned that, having a heavier rear fuselage and better forward visibility than the previous model, you needed a lot of nose-down trim and awareness of your angle of attack to prevent stalling at the top of the launch. No problem, standard type conversion briefing. Same could have been done for the 737MAX, rather than install one more thing that could go wrong.
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With a properly trained crew, the 737Max flights could have been saved;
The MCAS was introduced to remove the need for specific type training for 737-rated pilots. When I bought my first glider I was warned that, having a heavier rear fuselage and better forward visibility than the previous model, you needed a lot of nose-down trim and awareness of your angle of attack to prevent stalling at the top of the launch. No problem, standard type conversion briefing. Same could have been done for the 737MAX, rather than install one more thing that could go wrong.
Wasn't the basic problem, that Boeing tried to stretch and extend an old airplane - the 737 - instead of designing a new one.
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You design each station for the 100 or 1000 year event at that site. AFAIK that does not include tsunamis on the UK or French coasts.
Which means that in 1000 years every nuclear reactor in the world will have poisoned an area the size of belgium?
They should be designed for a timescale equal to the radioactivity, that would be worldwide. Tsunamis are common in a 1000 year timescale
https://en.m.wikipedia.org/wiki/1755_Lisbon_earthquake
Fukushima was designed for a once in 50 year timescale
https://www.worlddata.info/asia/japan/tsunamis.php
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The design life of a nuclear power station is rarely more than 20 years. Most seem to last longer, but subject to major upgrade if not dismantling and demolition.
Given that the halflife of some fission products exceeds 250,000 years, and the fact that no manmade structure has survived half as long, your preferred timescale is unrealistic.
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The design life of a nuclear power station is rarely more than 20 years. Most seem to last longer, but subject to major upgrade if not dismantling and demolition.
Given that the halflife of some fission products exceeds 250,000 years, and the fact that no manmade structure has survived half as long, your preferred timescale is unrealistic.
So nuclear meltdowns all round? That is not a solution
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On the contrary.
There are currently around 440 operating nuclear power reactors, the oldest being 52 years old, with 3 major incidents of which only Chernobyl resulted in more than 10 attributable deaths. Compare this with an average of 50 deaths per year in coal mines in the USA alone over the last 50 years (and this in probably the most unionised and safety-conscious country of all) and you can see why nuclear power is regarded as safe.
The most telling statistic is the 16,000 deaths caused by the tsunami that damaged Fukushima and almost completely ignored by the world's press. Water is dangerous.
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On the contrary.
There are currently around 440 operating nuclear power reactors, the oldest being 52 years old, with 3 major incidents of which only Chernobyl resulted in more than 10 attributable deaths. Compare this with an average of 50 deaths per year in coal mines in the USA alone over the last 50 years (and this in probably the most unionised and safety-conscious country of all) and you can see why nuclear power is regarded as safe.
The most telling statistic is the 16,000 deaths caused by the tsunami that damaged Fukushima and almost completely ignored by the world's press. Water is dangerous.
Sorry Alan but chernobyl poisoned a huge area, it caused only 4000 deaths because of the luck of the wind direction. If the wind blew toward Kiev we could be looking at over 1 million. Plus the fact that in 50 years of nuclear generation a huge area of land in 2 locations is now inaccessible.
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Which is why you shouldn't deliberately ignore the operating manual. That's nearly two whole days' worth of COVID deaths in Brazil, a quarter of the number of people drowned by the Fukushima tsunami, or 30% more than were killed on 9/11. The difference being that none of these other events ever had an intended upside like actually supplying electricity.
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Which is why you shouldn't deliberately ignore the operating manual. That's nearly two whole days' worth of COVID deaths in Brazil, a quarter of the number of people drowned by the Fukushima tsunami, or 30% more than were killed on 9/11. The difference being that none of these other events ever had an intended upside like actually supplying electricity.
Lucky so far, Kiev is an area of 5 million people. But does not poison even 1 percent as much land, for not 1 percent of the time, does not build radio nucleides in the environment. The fear of Nuclear war was not just the bombs but the Fallout.
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Given that the halflife of some fission products exceeds 250,000 years, and the fact that no manmade structure has survived half as long, your preferred timescale is unrealistic.
Those aren't the half lives that are the most problematic. The long half life species decay very slowly and so give off very little radiation over a very long period. And the very short half life species decay rapidly and are soon gone; just keep out of their way for a while. No, it's the intermediate ones, that have a half life roughly comparable to human life spans that are the main problem, they give off large amounts of radiation for annoying lengths of time.
For example caesium 137 (30 year half life) and tritium (11 year half life). You don't want to get them inside you or be near them.
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Given that the halflife of some fission products exceeds 250,000 years, and the fact that no manmade structure has survived half as long, your preferred timescale is unrealistic.
Those aren't the half lives that are the most problematic. The long half life species decay very slowly and so give off very little radiation over a very long period. And the very short half life species decay rapidly and are soon gone; just keep out of their way for a while. No, it's the intermediate ones, that have a half life roughly comparable to human life spans that are the main problem, they give off large amounts of radiation for annoying lengths of time.
For example caesium 137 (30 year half life) and tritium (11 year half life). You don't want to get them inside you or be near them.
Yes and no.
If you are looking at long term storage of waste, the intermediate half life ones are less of an issue.
Things like 90Sr will decay a thousand fold over a period roughly the same as St Paul's Cathedral has lasted- so we know how to build a structure that will contain them.
It's the hundred-year and up half lives we aren't so sure about. We have some thousand-year-old buildings, but not many
Also, tritium ( decay half life 12.32 years) isn't much of a problem because it doesn't stay in the body.
https://en.wikipedia.org/wiki/Biological_half-life#Water
(And the decay energy is relatively low, so it does less damage)
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But does not poison even 1 percent as much land, for not 1 percent of the time, does not build radio nucleides in the environment.
I assume you are talking about coal. A relatively minor accident at Aberfan killed 144 people, mainly children, above ground - about the same number as died of acute radiation effects at Chernobyl. Burning coal releases polonium into the atmosphere, and the stuff that comes out of oil wells can really light up the room without burning.
Fact is that however careful you are with coal, it is dangerous, and wind is unreliable. We have to go a long way to replace nuclear power with anything better.
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Also, tritium ( decay half life 12.32 years) isn't much of a problem because it doesn't stay in the body.
https://en.wikipedia.org/wiki/Biological_half-life#Water
(And the decay energy is relatively low, so it does less damage)
Not quite. The low energy betas have a very short range in tissue so actually cause a lot of damage in a few cells - it's as nasty as many alpha emitters, and the Environment Agency get very exercised about it.
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Not quite. The low energy betas have a very short range in tissue so actually cause a lot of damage in a few cells - it's as nasty as many alpha emitters,
A high energy beta particle, on the way to becoming "just another electron", will always pass through a stage of being a low energy beta.
So it will always do more damage.
If the EA don't know that, feel free to tell them.
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Given that the halflife of some fission products exceeds 250,000 years, and the fact that no manmade structure has survived half as long, your preferred timescale is unrealistic.
Those aren't the half lives that are the most problematic. The long half life species decay very slowly and so give off very little radiation over a very long period. And the very short half life species decay rapidly and are soon gone; just keep out of their way for a while. No, it's the intermediate ones, that have a half life roughly comparable to human life spans that are the main problem, they give off large amounts of radiation for annoying lengths of time.
For example caesium 137 (30 year half life) and tritium (11 year half life). You don't want to get them inside you or be near them.
I understand what you are saying viz a vi's zapping radiation but it is usually if you injest these particles that they are the greatest threat. Plutonium has an very long half life, if on the skin it can be washed off, if injested it is pretty much lethal.
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Plutonium is a real bugger because it is chemically active, forms compounds with pretty much anything, so can accumulate in bones instead of being excreted, and emits α particles that do massive damage in a short distance, at least 20 and possibly 200 times more biologically damaging than the same dose of γ radiation.
The practical problem with α and low-energy β radiation isn't shielding from them (a sheet of paper will stop almost all α's) but detecting them in order to prevent or locate ingestion. Never mind needles, you can have a haystack of Pu or Th and not know about it unless you have reason to suspect its presence and something a bit smarter than your average geiger counter to detect it.
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The long half life species decay very slowly and so give off very little radiation over a very long period. And the very short half life species decay rapidly and are soon gone; just keep out of their way for a while. No, it's the intermediate ones, that have a half life roughly comparable to human life spans that are the main problem, they give off large amounts of radiation for annoying lengths of time.
For example caesium 137 (30 year half life) and tritium (11 year half life). You don't want to get them inside you or be near them.
I understand what you are saying viz a vi's zapping radiation but it is usually if you injest these particles that they are the greatest threat. Plutonium has an very long half life, if on the skin it can be washed off, if injested it is pretty much lethal.
There's several isotopes, Pu 238 and Pu 241 have half lives of 87.74 and 14 years respectively, and I'm pretty sure those are the problematic ones. As I say, the ones with half lives comparable to human lifespans are the main issue.
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want to get them inside you or be near them.
I understand what you are saying viz a vi's zapping radiation but it is usually if you injest these particles
I'm pretty sure they are not the ones that are mentioned in the "radioactive for thousands of years" phrase. Neptunium is another problematic component of nuclear waste and amongst the longest lived. I am not sure of the amount of these transuranic metals dispersed but I think it was quite low due to their characteristics.
https://en.m.wikipedia.org/wiki/Isotopes_of_neptunium
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Biological half lives are interesting in their way (it is for example interesting that, though the chemistry of uranium and plutonium are quite similar, their biological half lives are very different.)
Which isotopes in reactor waste are "worst" depends on what you plan to do with them.
It's generally a bad idea to ingest them..
Since they do get produced by reactors, you have to workout what to do with them.
It's obviously bad if they are set free by a melt down.
On that basis radioactive iodine is a big problem. the yield is relatively high, it's trapped rather well in the body- specifically in the thyroid and the half lives of the various isotopes are such that they do a lot of damage.
Equally importantly, it's easy to form volatile and/ or soluble compounds of iodine so it's likely to escape.
By the time you notice that you have a meltdown it's a bit late to do much about it.
A proper containment vessel would be a good idea.
Assuming it survives whatever cause the meltdown, you can then "simply" bury it in concrete.
Then you run into the other problem; the mausoleum.
We simply have no experience of how to build a structure that will last until the long lived isotopes decay.
We can build something which will stand for 300 years- by which time the things that we normally worry about- notably strontium and caesium - will decay.
And we don't need to worry much about things with million year half lives because their specific activity will be low.
But there's a bunch of isotopes- 239Pu is usually cited as the example- which will be dangerous over a period much longer than we can plan for (roughly quarter of a million years).
So, it's not so much a matter of "We don't know how to solve the problem" it's a matter of "There are lots of problems and we don't know how to solve any of them."
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radioactive iodine is a big problem. the yield is relatively high, it's trapped rather well in the body-
I have heard that some countries have a stockpile of potassium iodide.
- If you know there is a radioactive release impending (and are prepared to admit it to the population...)
- You can dispense potassium iodide tablets (especially to growing children)
- Apparently, the thyroid, after being given a high does of iodine goes quiescent for a while, and reduces iodine uptake from the diet
See: https://en.wikipedia.org/wiki/Iodine-131#Treatment_and_prevention
Evacuation is another important public health tool to reduce exposure...
- But if you aren't prepared to admit that anything is wrong until the radioactive plume is detected 3 countries away, it is a bit late!
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Evacuation is not necessarily the best option.
There were several deaths caused by traffic chaos during the voluntary evacuation at Three Mile Island, and none attributable to the meltdown itself. In comparison, the controlled and orderly evacuation of the Chernobyl region did not add to the death toll despite the far more serious nature of the explosion.
The emergency stockpile is usually potassium iodate rather than iodide because it has a longer shelf life.
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The emergency stockpile is usually potassium iodate rather than iodide because it has a longer shelf life.
Which is odd- because both are perfectly stable in dry conditions, and you would expect to keep them in closed containers.
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- Apparently, the thyroid, after being given a high does of iodine goes quiescent for a while, and reduces iodine uptake from the diet
To a good approximation, it's simpler tan that.
You can easily give someone a gram of iodide.
They will pee most of it out.
If they also inhale a picogram of radioactive iodide that will mix with the ingested stuff from the tablets.
And, in the same way, they will pee most of it out.
Once the thyroid's need for iodide is sated it doesn't bother to trap it.
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The emergency stockpile is usually potassium iodate rather than iodide because it has a longer shelf life.
Which is odd- because both are perfectly stable in dry conditions, and you would expect to keep them in closed containers.
Two conditions that, as we saw with COVID PPE, our wondrous government is unable to guarantee. I recall a happy evening spent with the Home Office Civil Protection scheme where "new" personal dose rate meters were handed out. Half of them did not work, mainly due to contact corrosion. The problem with "emergency-only" stock is that you either have to inspect it every couple of years (expensive, but essential for life rafts and other obviously perishable kit) or ensure that it is indefinitely stable in an affordable and easily useable package (cunning chemistry). Hence KIO3 which should last 100 years or so in a leaky hangar or soggy cave (read "secure emergency store").
Sealed polyethylene bag technology is surprisingly modern - the patents are dated from 1965 and vacuum sealing somewhat later - and not all polyethylene grades are longterm compatible with KI in the presence of moisture - but emergency KIO3 stocks may date from 1957 (Windscale) in "medical" pill tubs.
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Two conditions that, as we saw with COVID PPE, our wondrous government is unable to guarantee.
For the record, our government made the decision not to replace the stock when it went out of date. That's separate bit of negligence.
There's a point where environmentally controlled rooms to stock rubber gloves cost more than just regularly buying new ones (and dumping the old ones on the surplus market) .
Our government chose to do neither and just cross their fingers.
They call this "doing all they could".
Potassium iodide melts at 681 degrees C; that's fairly stable.
It's on the WHO list of essential medicines.
This option may be useful in emergency situations.
https://en.wikipedia.org/wiki/Portable_water_purification#Iodine
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Potassium iodide melts at 681 degrees C; that's fairly stable.
Indeed, but it is also deliquescent (guess who spent the sober hours of his youth studying the response of alkali halides to radiation?) which makes longterm storage a bit problematic.
At the risk of offending the Official Secrets Acts, I can however reveal that HM Government used to keep 5 years' worth of "toilet paper, hard, military and government service for the use of" in a hangar at RAF Staverton. But that's another story.
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Potassium iodide melts at 681 degrees C; that's fairly stable.
Indeed, but it is also deliquescent (guess who spent the sober hours of his youth studying the response of alkali halides to radiation?) which makes longterm storage a bit problematic.
At the risk of offending the Official Secrets Acts, I can however reveal that HM Government used to keep 5 years' worth of "toilet paper, hard, military and government service for the use of" in a hangar at RAF Staverton. But that's another story.
In these times of bog roll shortages Alan you run the risk of being hung as a traitor if a sudden looting should happen on HMs W. C. supplies.
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Not a problem. Each sheet was labelled "official use only", if I recall correctly, so nobody would have dared steal it. And Staverton is now a civilian airport.
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Funny enough about 3 months before Fukushima made KI unobtanium, I bought a 500g bottle of analytic grade KI, as I wanted a coolant system antibacterial that would stop the annoying growth of biofilm that would clog the system of a machine cooler. 50g into the water, and it never developed any biofilm after that, while before the water would, despite the tank being bare brass sheet, and thus dumping prolific amounts of copper in the system, tend to develop a thick biofilm after around 6 months, the film living on the plastic piping and the other plastic parts. Cleaning would mean stripping, and replace all plastic polyurethane piping, and scrubbing all parts in the tank, and then the biofilm would return, even with nearly a kilogram of (expired) methyl paraben as preservative. Yes preservatives with a shelf life.....
After the incident, you could not buy KI for months, all stocks having been bought up by all and sundry, and prices skyrocketed to insane levels. Still got the bottle, though by now it is half empty, the rest having evaporated with time.