Yep, statistically speaking, there is more to be worried about from a hydroelectric dam collapse than a nuclear incident.Quote:
Originally Posted by nigelred5
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Yep, statistically speaking, there is more to be worried about from a hydroelectric dam collapse than a nuclear incident.Quote:
Originally Posted by nigelred5
OK then. Please tell me the danger posed by Pu239. Do you know what it is, what it does and what threat it poses?Quote:
Originally Posted by race aficionado
No? I thought not otherwise you wouldn't have quoted some irrelevant statistic about a half life of a product that is so dangerous that the US Navy chuck a load of it in a sealed, preasurised compartment and then chuck in a crew of their finest Submariners ;)
Then we have Pu244 which has a half life of 80 Million Years. That's a much more interesting statistic but I guess we can't go back to the dawn of creation ;)
Seeing as everyone is a fan on cutting and pasting, I though I would paste a little bit about the toxicity on Plutonium. I'm sure everyone read at least the background of what the dangers are before posting on here so this should be nothing new :D
I think the things you are worried about are things like radio-iodine (8 day half life), Strontium (28 Years) and Caesium (30 Years). These are pretty nasty when exposed like Chenybol but again, are used in many medical, scientific and commercial applications.Quote:
Toxicity
Isotopes and compounds of plutonium are dangerous due to their radioactivity. Contamination by plutonium oxide (spontaneously oxidized plutonium) has resulted from a number of military nuclear accidents where nuclear weapons have burned.[85]
The alpha radiation plutonium emits does not penetrate the skin but can irradiate internal organs when plutonium is inhaled or ingested.[32] The skeleton, where plutonium is absorbed by the bone surface, and the liver, where it collects and becomes concentrated, are at risk.[31] Plutonium is not absorbed into the body efficiently when ingested; only 0.04% of plutonium oxide is absorbed after ingestion.[32] What plutonium is absorbed into the body is excreted very slowly, with a biological half-life of 200 years.[86] Plutonium passes only slowly through cell membranes and intestinal boundaries, so absorption by ingestion and incorporation into bone structure proceeds very slowly.[87][88]
Plutonium is more dangerous when inhaled than when ingested. The risk of lung cancer increases once the total dose equivalent of inhaled radiation exceeds 400 mSv.[89] The U.S. Department of Energy estimates that the lifetime cancer risk for inhaling 5,000 plutonium particles, each about 3 microns wide, to be 1% over the background U.S. average.[90] Ingestion or inhalation of large amounts may cause acute radiation poisoning and death; no human is known to have died because of inhaling or ingesting plutonium, and many people have measurable amounts of plutonium in their bodies.[76]
The "hot particle" theory in which a particle of plutonium dust radiates a localized spot of lung tissue has been tested and found false – such particles are more mobile than originally thought and toxicity is not measurably increased due to particulate form.[87]
However, when inhaled, plutonium can pass into the bloodstream. Once in the bloodstream, plutonium moves throughout the body and into the bones, liver, or other body organs. Plutonium that reaches body organs generally stays in the body for decades and continues to expose the surrounding tissue to radiation and thus may cause cancer.[91]
Several populations of people who have been exposed to plutonium dust (e.g. people living down-wind of Nevada test sites, Hiroshima survivors, nuclear facility workers, and "terminally ill" patients injected with Pu in 1945–46 to study Pu metabolism) have been carefully followed and analyzed.
These studies generally do not show especially high plutonium toxicity or plutonium-induced cancer results.[87] "There were about 25 workers from Los Alamos National Laboratory who inhaled a considerable amount of plutonium dust during the 1940's; according to the hot-particle theory, each of them has a 99.5% chance of being dead from lung cancer by now, but there has not been a single lung cancer among them."[92][93]
Plutonium has a metallic taste.[94]
Criticality potential
http://upload.wikimedia.org/wikipedi...um-sphere.jpeg http://bits.wikimedia.org/skins-1.17...gnify-clip.png
A sphere of simulated plutonium surrounded by neutron-reflecting tungsten carbide blocks in a re-enactment of Harry Daghlian's 1945 experiment
Toxicity issues aside, care must be taken to avoid the accumulation of amounts of plutonium which approach critical mass, particularly because plutonium's critical mass is only a third of that of uranium-235.[7] A critical mass of plutonium emits lethal amounts of neutrons and gamma rays.[95] Plutonium in solution is more likely to form a critical mass than the solid form due to moderation by the hydrogen in water.[13]
Criticality accidents have occurred in the past, some of them with lethal consequences. Careless handling of tungsten carbide bricks around a 6.2 kg plutonium sphere resulted in a fatal dose of radiation at Los Alamos on August 21, 1945, when scientist Harry K. Daghlian, Jr. received a dose estimated to be 5.1 Sievert (510 rems) and died 28 days later.[96] Nine months later, another Los Alamos scientist, Louis Slotin, died from a similar accident involving a beryllium reflector and the same plutonium core (the so-called "demon core") that had previously claimed the life of Daghlian.[97] These incidents were fictionalized in the 1989 film Fat Man and Little Boy.
In December 1958, during a process of purifying plutonium at Los Alamos, a critical mass was formed in a mixing vessel, which resulted in the death of a crane operator named Cecil Kelley.[98] Other nuclear accidents have occurred in the Soviet Union, Japan, and many other countries.[98]
This might not mean much to our US friends, but if the Japanese reactor were a car, it would be exempt from road tax, have no requirement to fit seatbelts and display a silver on black numberplate. Yes, it's that old! So to say we shouldn't have new plants based upon a 'failure' of an extremely old plant during extreme conditions is foolish indeed.
Shhhhhhhh. Don't wake them up. I've just got them off to sleep. ;)Quote:
Originally Posted by Mark
My point is that we are consuming a non-renewable energy resource at an exponential rate.Quote:
Originally Posted by Bob Riebe
Coal is by far the dirtiest source of energy and likely the highest contributor to deaths and human health issues.
When figures for cost per kilowatt-hour include the disposal and maintenance of spend rods, nuclear is still comparable with fossil fuel energy production.Quote:
Originally Posted by Bob Riebe
:?: Please re-read my post :)Quote:
Originally Posted by Bob Riebe
A few more facts to put the world’s energy demands in context:
The USA, with 10% of the world’s population consumes approximately 25% of the world’s oil.
Approximately 30% of which is used to fuel passenger vehicles.
Sadly North Americans are fixated on the use of the passenger vehicle as their primary means of transportation.
If North Americans could reduce the numbers of vehicles on the road during weekday rush hour periods by half, the world’s energy problems would be solved. What is required during rush hours is a means of transporting masses of people from their homes to either a downtown core, or central work district. The passenger vehicle is the most inefficient mode of mass transportation to accomplish this. Next time you’re stuck in rush hour traffic, look around you and count the number of vehicles in which there is more than one person, yet the vehicle is easily capable of transporting 4 :mark: .
A major step to solving the world’s energy problem is that we (specifically western countries) must drastically consume fewer resources. To do that requires radical lifestyle changes. Until we acknowledge that, we can forget about alternate fuel sources such as solar or wind.
So are you the first one to sign up for not being able to turn on a light at night when the wind isn't blowing? Tung only half in cheek.Quote:
Originally Posted by schmenke
I see wind as only being useful if it's tied up with electricity storage. Currently the only cost effective way to store electricity cheap(ish) and efficiently is to use hydro electric power stations.Quote:
Originally Posted by chuck34
All power generation has it's downsides, e.g. conventional coal and nuclear stations have long lead times to power up and down, so responding to changes in demand is not possible. In the UK we have coal stations on 'spinning reserve' i.e. burning coal but not generating power as it isn't needed! And nuclear it makes little difference if you're running at full speed or not.
Wind and wave and to a point tidal, has the opposite issue that it only gives you power intermittantly. Which is why you need hydro in there too.
Currently the only solution which gives you cheap power station construction costs, an ability to quickly adjust for demand is gas. However most of that gas comes from Russia and could be cut off at any moment, and that isn't going to last forever in any case.
Managed to find an interesting artical with pretty pictures.
http://www.doeni.gov.uk/niea/polluti...ioactivity.htm
Also, I found this lovely little quote but cannot substantiate the source.
http://www.blackcatsystems.com/GM/safe_radiation.htmlQuote:
While it is true that there is a slight increase in radiation does due to living close to a nuclear power plant, typically on the order of 0.01 mrem a year (insignificant), the average dose from living near a coal fired power plant is three times as high! This is due to the release of uranium/etc naturally mixed in with the coal.
I’m not saying that at all.Quote:
Originally Posted by chuck34
What I am trying to say is that energy output from alternate sources such as wind, solar and tidal are grossly over estimated, not to mention have practical limitations as pointed out by Mark. I for one do not want my tax dollar invested in exploring these as long-term options to replace conventional energy production. Specifically, living in Canada where we need a reliable and consistent source to hear our homes 9 months out of the year!
I guess the point that I’m trying to make is that the only way to ensure global energy sources for the future is to accept serious lifestyle changes and consume less now. If we don’t want to do accept this then there are only two viable options:
1. Start to exploit the vast reserves of petroleum resources in environmentally sensitive areas such as the Arctic and South America (I recently read one report that estimated the oil reserves in the rain forest region alone is close to 1 trillion barrels); or,
2. Go nuclear.
I guess from where I'm sitting, the state of physics/engineering being what they are, barring some future technical enhancement that I am unaware of right now, the only viable option is a combination of your #1 and #2. We need to exploit our resources in the short term while we ramp up our nuclear capability.Quote:
Originally Posted by schmenke
Consuming less now (or at any time in the future), and/or radically changing our lifestyles are not viable options. Like I said, who is going to be the first one to sign up for not having their lights come on at night when the wind isn't blowing? Do you know anyone that would sign on for that?