Secret Squirrel has discovered and even worse condition at Japan's Fukushima nuclear plant,more serious than the melted down reactors,and that is the method of, and storage of, the spent fuel rods in the reactor plant,being above the reactors,and has learned Fukushima’s spent nuclear fuel rods are critically dangerous,in short where there's smoke there's fire.
Where there's no containment, there's radiation,and Fukushima has buildings virtually entirely blown away, all vastly open to the atmos.Buildings,which when they blew,due to the ignition of escaped hydrogen gas emitted by the damaged reactors,damaged,if not destroyed the fuel rod containment pools, and even yet having blown some,or many, of said rods entirely out of the building, and out of their pools where they lie strewn about,emitting ever increasing radiation, in the forms of gas,metals,oxides, and solid particles, highly radioactive ones, ever increasing as the uncooled rods now go to self re-criticality.Where there's smoke, there's fire, and such a fire is vastly worse,in terms of radiation, than the melted down reactors can produce,due to the enormous quantity of said fuel rods that were, and are,stored there.It all commences as any pool looses integrity due to various cause, the fuel bundles are exposed and then it starts,the zirconium cladding on the fuel rods bursts into flames if exposed to air for hours when a storage pool looses its water and also as heat rise internally in the rod of the nuclear materials,re-criticallity commences to chain,vast amounts of assorted radiation is released in various forms,all undesirable.Also as water in a given pool reduces, the temperature of the rods rises,the water boils, steams off, less water, and goes cyclical to dry and ever increasing re-criticality. Now study the situation as Squirrel sees it.Figures provided by the Tokyo Electric Power Company on Thursday show that most of the dangerous uranium at the powerplant is in the spent fuel rods, not the reactor cores.Here we ponder the words of TEPCO...The company said that a total of 11,195 spent fuel rod assemblies were stored at the site. That is about four times as much radioactive material as in the reactor cores combined…….the zirconium cladding on the fuel rods could burst into flames if exposed to air for hours when a storage pool lost its water Spent rods the biggest hazard, says Sydney Morning Herald, Keith Bradsher and Hiroko Tabuchi, March 19, 2011 YEARS of procrastination in deciding on long-term disposal of highly radioactive fuel rods from nuclear reactors are coming back to haunt Japanese authorities as they try to control fires and explosions at the stricken Fukushima Daiichi nuclear power station.
Some countries have tried to limit the number of spent fuel rods that accumulate at nuclear power plants: Germany stores them in costly casks, for example, and China sends them to a desert storage compound in the western province of Gansu.America has at one time also done this,but strangely abandonned this safer method of storage, if nuclear can be safe at all,or at least in a tiny bit. But Japan, like the United States, has kept ever-larger numbers of spent fuel rods in temporary storage pools at the powerplants, where they can be guarded with the same security provided for the plants.Obama even yet ordered,on achieving office,ordered the shutdown of an underground storage facility at Yucca Flats(Mountain),deep in the earth, troubled by greens dismayed at the thought of that,however Obama has angered Ganesha,The Elephant God, and others,and Obama may have lacked authority to have closed Yucca Mountain. And so, the US now stores the rods in the same fashion the Japanese do, mostly.Is he likely to reverse himself,at risk of irritating the greens and ordering it now reopened, by his command?Well magine,Vermont Yankee has a staggering 690 tons of spent fuel rods on site,you can imagine how much others have. All cooling water is gone from the spent-fuel pool at one of the crippled nuclear reactors in Japan, causing the release of high levels of radiation, Gregory Jaczko, chairman of the U.S. Nuclear Regulatory Commission, told members of Congress. Radioactivity has been heating the pools at three of the plant's reactors since the plant's cooling systems were disabled by a March 11 earthquake and tsunami, officials said.
Exposed, the spent fuel rods can catch fire and melt, spewing radiation into the atmosphere, said Robert Kelley, an engineer in Vienna who used to lead the Nuclear Emergency Response at Los Alamos National Laboratory in New Mexico. Unlike the plant's reactors, the pools aren't encased by steel and concrete. The pool water also shields workers. With the top of the fuel rods exposed, a worker at the pool lip would receive a fatal radiation dose in 16 seconds, David Lochbaum, a nuclear physicist for the Union of Concerned Scientists and a former NRC safety instructor, said in a conference call. Water in the spent fuel pool at the No. 4 reactor may be boiling, Japan's Nuclear and Industrial Safety Agency said on March 15. Temperatures in the rod-cooling pools of the shuttered No. 5 and No. 6 reactors rose as high as 63 degrees Celsius (145 degrees Fahrenheit) at 2 p.m. yesterday from 60 degrees Celsius at 7 a.m., a Tokyo Electric official said. Reactor pool No. 4 contains 142 tons of fuel that could burn on exposure to the atmosphere, Marvin Resnikoff, a nuclear physicist for Washington-based Physicians for Social Responsibility, said in a telephone press conference arranged by the group. He cited Tokyo Electric statements.
Japanese authorities are concerned about the condition of the pools of units 3 and 4, the International Atomic Energy Agency said yesterday. Military helicopters may be used to drop water on reactor No. 3 and workers are planning to spray water into unit 4, according to the IAEA. "This is going to be a problem for months," Resnikoff said. "Water serves as both cooling and radiation shielding and workers can't get close to it when the water is gone." The pools contain enough radioactive cesium to make areas around the plant uninhabitable should it spread by fire and wind, Ira Helfand, a past president of Physicians for Social Responsibility. Whether contamination occurs remains to be seen, he said. The risk of the fuel ponds getting hot enough to start a nuclear reaction remains remote, said Geoff Parks, a nuclear engineer, also at the University of Cambridge. The pond would need to reach about 2,200 degrees Celsius, he said.
Science Insider noted yesterday: The Daiichi complex in Fukushima, Japan … had a total of 1760 metric tons of fresh and used nuclear fuel on site last year, according to a presentation by its owners, the Tokyo Electric Power Company (Tepco). The most damaged Daiichi reactor, number 3, contains about 90 tons of fuel, and the storage pool above reactor 4, which the Nuclear Regulatory Commission’s (NRC’s) Gregory Jaczko reported yesterday had lost its cooling water, contains 135 tons of spent fuel. The amount of fuel lost in the core melt at Three Mile Island in 1979 was about 30 tons; the Chernobyl reactors had about 180 tons when the accident occurred in 1986.According to Associated Press, there were – at the time of the earthquake and tsunami – 3,400 tons of fuel in seven spent fuel pools plus 877 tons of active fuel in the cores of the reactors.That totals 4,277 tons of nuclear fuel at Fukushima. Which means that there is almost 24 times more nuclear fuel at Fukushima than Chernobyl.If any of the spent fuel rods in the pools did indeed catch fire, nuclear experts say, the high heat would loft the radiation in clouds that would spread the radioactivity.
Here we see the worsening situation through
http://ecocentric.blogs.time.com/2011/03/15/a-new-threat-in-japan-radioactive-spent-fuel/#ixzz1LLjvCdQC
Excerpts start.............
“It’s worse than a meltdown,” said David A. Lochbaum, a nuclear engineer at the Union of Concerned Scientists who worked as an instructor on the kinds of General Electric reactors used in Japan. “The reactor is inside thick walls, and the spent fuel of Reactors 1 and 3 is out in the open.” Mr. Lochbaum, who formerly taught reactor operation for the Nuclear Regulatory Commission, said the pools measured about 40 feet long, 40 feet wide and 45 feet deep. The spent fuel, he added, rested at the pool’s bottom and rose no higher than 15 feet from the bottom.That means that in normal operations, the spent fuel is covered by about 30 feet of cooling water.Depending on the freshness of the spent fuel, Mr. Lochbaum said, the water in an uncooled pool would start to boil in anywhere from days to a week.
The water would boil off to a dangerous level in another week or two.Once most of the fuel is exposed, he said, it can catch fire.If the spent fuel is a few months old, most of the iodine 131 — one of the most dangerous radioactive byproducts in spent fuel — will have decayed into harmless forms.But the cesium 137 in the spent fuel has a half-life of 30 years, meaning it would take about two centuries to diminish its levels of radioactivity down to 1 percent.It is cesium 137 that still contaminates much land in Ukraine around the Chernobyl reactor, which suffered a meltdown in 1986. What happens to exposed spent fuel rods? The rods get so hot that the zirconium cladding catches fire. As the zirconium turns into zirconium oxide -- another exothermic reaction -- all the fission by-products inside the rods as well as any leftover uranium oxide and plutonium oxide will be exposed to the atmosphere. Given that the heat of the fire will cause convection, these by-products easily become an aerosol, enter the atmosphere, and disperse in the prevailing winds. What's the immediate impact? The spent fuel releases a lot of radiation in the vicinity of the plant. What's the impact over a broader area? The scenario of a high volume of airborne radioactive compounds entering the atmosphere is daunting.
Some emit gamma or beta radiation that the human body receives from outside. Some emit alpha particles, so they are dangerous if inhaled or ingested. Some like iodine are biologically absorbed (this is why potassium iodide tablets saturate your body with iodine and prevent uptake of the radioactive iodine isotope)Some like plutonium are chemically toxic in addition to being highly radioactive. Is this similar to Chernobyl? It's not, in terms of how it began. But it could be, in terms of impact.Spent fuel is taken out of the reactor and replaced by new fuel. Nuclear power plants do this periodically—in some cases, every year. Once they are removed, however, spent nuclear fuel is very "hot and dirty"--it's physically hot, but it also emits lots of nasty radiation. So you have to cool it in a special pool for 5 to 10 years to let the radioactivity fade. Pick your poison. Fresh fuel is hotter and more radioactive, but is only one fuel assembly. A pool of spent fuel will have dozens of assemblies. One report from Sankei News said that there are over 700 fuel assemblies stored in one pool at Fukushima. If they all caught fire, radioactive particles—including those lasting for as long as a decade—would be released into the air and eventually contaminate the land or, worse, be inhaled by people. "To me, the spent fuel is scarier. All those spent fuel assemblies are still extremely radioactive," Dalnoki-Veress says. If the water that boils away cannot be replaced, the water level will drop, exposing the rods. The rods will begin to heat, which can lead to damage of the rod, or possibly a partial or complete meltdown . All of those consequences would lead to a release of radiation from the damaged rods. The amount released would depend on the severity of damage to the rods, the amount of spent fuel in the pool, and the length of time the rods have been in the pool.
Two of the radioactive gases released from fuel rods are iodine-131 and cesium-137. Because radioactive iodine-131 has a short half-life (eight days), it begins to decay quickly once the fuel is removed from the reactor core—so radiation releases from spent fuel will have much lower levels of iodine-131 than releases from the reactor core. However, cesium-137, which has a longer half-life (30 years), decays much more slowly, so levels will remain high in the spent fuel. Cesium-137 contamination from the Chernobyl accident was the main reason authorities had to establish an exclusion zone around that reactor. It is important to note that spent fuel pools are not as isolated from the environment as the reactor core, because the pools are located outside the primary containment structure. So even if the total amount of radiation released by damaged fuel rods in a spent fuel pool is less than that released by similarly damaged fuel rods in the reactor core, the fraction of that radiation that escapes into the atmosphere from the spent fuel pools is likely to be much higher. Since the net release into the air will be determined by the combination of these two factors—how much radiation is released by the fuel rods, and how much of that escapes into the environment— greater levels of radiation could result from the loss of cooling to a spent fuel pool than the loss of cooling to a reactor.
From images, 1 and 3 no longer have intact pools, in fact the rods are somewhere in the building wreckage, and also scattered round and about, merrily spewing radiation such as caesium etc............... spent fuel rods pose grave danger, literally, as bad as and yet worse than, that of reactor core meldown,explosion.........you see while they are less, there are enormously more,and they are much more dangerously volotile, in that simply exposing them causes then to catch fire, and melt......emitting enormous amounts of radiation gases and particles, particles including the Caesium, which is tremendously radiactive, remaining so for many many yet years......caesium has a half life of 30 years, meaning it's radiation values decrease by half,but in terms of amounts.There are four kinds of isotopes that are likeliest to be emitted by the crippled Fukushima Daiichi plant, as well as the other three that have been taken offline: iodine-131, cesium-137, strontium-90 and plutonium-239. Iodine-131 is, in many ways, the most dangerous of the four, because it can lead to cancer — specifically thyroid cancer — in people exposed to it in the shortest time. Strontium and cesium are the next up the danger scale. While iodine tends to concentrate its damage to the thyroid, those two are not nearly so selective. "Strontium is chemicaly similar to calcium," says Dr. Ira Helfand, a board member for Physicians for Social Responsibility. "So it gets incorporated into bones and teeth and can stay there, irradiating the body, for a long time." Strontium is most commonly linked to leukemia.
More troubling, cesium and strontium linger not just in the body, but in the environment. Strontium has a half-life of 29 years; cesium's is 30. A radioactive isotope is generally considered dangerous for 10 to 20 times its half life, which in these cases tops out at about 600 years. Most worrisome of all is plutonium-239 — for a number of reasons. First of all, the vast majority of a fuel rod is made of plutonium, which means there's just more of it in play. What's more, says Helfand, "It's extraordinarily toxic." Plutonium exposure usually comes from inhalation rather than ingestion, so it's mostly associated with lung cancer. What's more, plutonium's half life is 24,000 years, which means anything released in Fukushima today could be around at dangerous levels for up to half a millon years.
Here we end selected excerpts........
As to the less subtle effects, the much more immediate effects result when there is .........People exposed to 100 full rems begin to experience nausea, one of the first signs of radiation sickness. At 200 rems and up you suffer loss of hair, suppression of the immune system, vomiting and bleeding. A dose of 300 rems is fatal to about 50% of people exposed. At 600 rems, nobody survives. In some cases, the timing of the dosing matters. It's much worse, for example, to absorb 300 rems in an hour than over the course of a year.Chernobyl cancers occurred in children because of the childhood growth process and dietary iodine deficienciesJapan has already, according to some estimates, released 50% of the amount of caesium-137 released by Chernobyl, and many experts say that the Fukushima plants will keep on leaking for months.And New Scientist reports that huge quantities of iodine-131 are being released in Japan: Six of the spent fuel rod pools are (or were) located at the top of six reactor buildings. One “common pool” is at ground level in a separate building.
Each “reactor top” pool holds up to 3450 fuel rod assemblies. The common pool holds up to 6291 fuel rod assemblies. [The common pool has windows on one wall which were almost certainly destroyed by the tsunami.] Each assembly holds sixty-three fuel rods. This means the Fukushima Daiichi plant may contain over 600,000 spent fuel rods. The fuel rods once stored atop reactor 3 may no longer be there: one of the several explosions at the Fukushima reactors may have damaged that pool.These pools are designed to store the intensively radioactive fuel rods that were already used in nuclear reactors. These “used” fuel rods still contain uranium (or in the case of fuel rods from reactor 3, they contain both uranium and plutonium from the MOX fuel used in that reactor).
In addition to the uranium and plutonium, the rods also contain other radioactive elements. These radioactive elements are created in the rods by the intense radiation around the rods when they are in the reactor core (before they are moved to the spent fuel pools).On average, spent fuel ponds hold five-to-ten times more long-lived radioactivity than a reactor core. Particularly worrisome is the large amount of cesium-137 in fuel ponds, which contain anywhere from 20 to 50 million curies of this dangerous radioactive isotope. With a half-life of 30 years, cesium-137 gives off highly penetrating radiation and is absorbed in the food chain as if it were potassium.These “used” fuel rods still contain uranium (or in the case of fuel rods from reactor 3, they contain both uranium and plutonium from the MOX fuel used in that reactor).
In addition to the uranium and plutonium, the rods also contain other radioactive elements.A single spent fuel pond holds more cesium-137 than was deposited by all atmospheric nuclear weapons tests in the Northern Hemisphere combined. These radioactive elements are created in the rods by the intense radiation around the rods when they are in the reactor core (before they are moved to the spent fuel pools),and are created when the spent fuel rises in temperature,or again takes part in a generated chain,in short,'re-criticality' occurs- a nuclear chain reaction starts among fuel rods in the ever drying pool..Without enough water to cover the, the fuel rods will keep on igniting, just like trick birthday candles keep re-igniting after we blow them out. Just like trick birthday candles, the only way to put out the fuel rods is to put them under water. Unlike trick birthday candles, the spent fuel rods burn hot (3300 degrees F) enough so that the radioactive material in the rods is aerosolized,and particularized: carried into the atmosphere in clouds of hot smoke,strontium,uranium,plutonium,caesium and yet more. And unlike our trick birthday candles, the spent fuel rods in reactor building 4 are four stories off the ground – just like the other five reactor spent fuel pools at Fukushima. And unlike our trick birthday candles, the radioactivity around the spent fuel rods is so high that no one can approach them to put out the fire.
When the reactors blew, the pools were obviously disturbed, and in at least two instances, spent fuel was ejected from the pools,if not the pool entirely compromised, and lie round and about the area of the explosion, and in the explosion debris in the former reactor housing, Also the buildings are entirely compromised and hence the radioactive result from fuel rods not being cooled,is spreading round and about and in to the atmos.The Genie is out of the bottle and there is just no stuffing it back in.Radiation readings? Of course of stunning magnitude,else the workers could go in there, and we all know they simply can't. As to the readings themselves, they,TEPCO,GE,the Japanese government, cannot in any way shape nor form be trusted to reveal the true readings and data on where the nuclear radiation is spreading or seeping in to.
As a metter of fact, strangely, on the other hand perhaps not, the Canadian government cannot be trusted, even with readings of the Japanese radiation cloud affecting and spreading to and into and through, Canada, as the Canadian Government has, incredibly,shut down their radiation monitoring system which is supposed to warn,inforn, and reveal the event. In short, the system specifically created for that use,has been shut down on orders of the Canadian Prime Minister, and government..useless thing to have isn't it, all round.If it isn't used, then without a doubt the equipment should be dismantled, and the people so employed in their evidently useless monitoring task,rendered redundant and unemployed. Buy a trustworthy geiger counter, and be your own monitor,your government is,in it's greatest majority,utterly and completely useless to you.
For your information from
http://en.wikipedia.org/wiki/Spent_nuclear_fuel
Substances released by "burning" spent fuel (1 Japanese reactor has plutonium in it's fuel,spent and otherwise,but not shown in table).
The chemical forms of fission products in uranium dioxide
Element Gas Metal Oxide Solid solution
Br Kr Yes - - -
Rb Yes - Yes -
Sr - - Yes Yes
Y - - - Yes
Zr - - Yes Yes
Nb - - Yes -
Mo - Yes Yes -
Tc Ru Rh Pd- Yes - -
Ag Cd In Sb - Yes - -
Te Yes Yes Yes Yes
I Xe Yes - - -
Cs Yes - Yes -
Ba - - Yes Yes
La Ce Pr Nd - - - Yes
Pm Sm Eu - - - Yes
No comments:
Post a Comment