Fukushima Now 72,000 Times Hiroshima Radiation (I hope this is alarmist reporting)

reply to post by Kailassa


Lord, our schools need overhauling.

Half-life is how long it takes for a radioactive isotope to lose HALF of its radioactivity. You can calculate how long it will take to lose its radioactivity, at least to an extremely small amount (because it will always be a little radioactive, just so low you can't measure it). If a half-life is 8 days, after 8 days it will be half as radioactive. If it started at 100 (totally arbitrary measurement), in 8 days it will be 50, 8 more days it will be 25, 8 ,more and it's 12.5, etc.

The isotope does not "become another substance" based on half-life decay.

I hope these articles will explain some more to the radiation spill and the cover-up.

What They're Covering Up at Fukushima

this second article is regrettable in german language.
German scientists

here is a google translation

Update 23/03/2011 at 18.10 clock: + + + Committee on Radiation Protection warns that meltdown in Fukushima 1 + + + IAEA measurements carried out up to 200 km from Fukushima I: High levels of beta-gamma contamination 16-58 km from the NPP found + + + Values ​​are comparable to Chernobyl + + + IAEA can not rule out that such high values ​​also occur at greater distances + + + More evacuation measures urgently required + + + There is warned against further trivialization of the contamination of the sea + + + We have now a worst-case scenario to do + + +

Originally posted by 00nunya00
reply to post by Kailassa

 

Lord, our schools need overhauling.

Half-life is how long it takes for a radioactive isotope to lose HALF of its radioactivity. You can calculate how long it will take to lose its radioactivity, at least to an extremely small amount (because it will always be a little radioactive, just so low you can't measure it). If a half-life is 8 days, after 8 days it will be half as radioactive. If it started at 100 (totally arbitrary measurement), in 8 days it will be 50, 8 more days it will be 25, 8 ,more and it's 12.5, etc.

The isotope does not "become another substance" based on half-life decay.

- You've just proved yourself a rude, ignorant fool. -

The substance loses it's radioactivity because it's unstable and breaks down to a less radioactive substance. This breakdown is what causes radioactivity. Radioactivity the energy released from this breakdown.

The parent can break down to a daughter which is a different isotope, or to a daughter which is a completely different element. Either way, a new substance has been formed.

Radioactive Decay
The decay, or loss of energy, results when an atom with one type of nucleus, called the parent radionuclide, transforms to an atom with a nucleus in a different state, or a different nucleus, either of which is named the daughter nuclide. Often the parent and daughter are different chemical elements, and in such cases the decay process results in nuclear transmutation. In an example of this, a carbon-14 atom (the "parent") emits radiation (a beta particle, antineutrino, and a gamma ray) and transforms to a nitrogen-14 atom (the "daughter"). By contrast, there exist two types of radioactive decay processes (gamma decay and internal conversion decay) that do not result in transmutation, but only decrease the energy of an excited nucleus. This results in an atom of the same element as before but with a nucleus in a lower energy state. An example is the nuclear isomer technetium-99m decaying, by the emission of a gamma ray, to an atom of technetium-99.

reply to post by Kailassa


Did you read what you just quoted?

You're wrong. End of story. You were asked "what is half-life?" And you answered "it's apples becoming oranges." FAIL. (And you had to U2U me to repeat your little insults? Reported).

And since you're dependent on Wikipedia, here

Half-life is the period of time it takes for a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms (radioactive decay), but may apply to any quantity which follows a set-rate decay. The original term, dating to 1907, was "half-life period", which was later shortened to "half-life" in the early 1950s.[1] Half-lives are very often used to describe quantities undergoing exponential decay—for example radioactive decay—where the half-life is constant over the whole life of the decay, and is a characteristic unit (a natural unit of scale) for the exponential decay equation. However, a half-life can also be defined for non-exponential decay processes, although in these cases the half-life varies throughout the decay process. For a general introduction and description of exponential decay, see the article exponential decay. For a general introduction and description of non-exponential decay, see the article rate law.

Click here for more information.

reply to post by Kailassa


What you're talking about is called "transmutation". Not half-life.

I'm not engaging you any more; you're not worth my time. Have a nice day, sweetheart.

Originally posted by 00nunya00
reply to post by Kailassa

 

What you're talking about is called "transmutation". Not half-life.

I'm not engaging you any more; you're not worth my time. Have a nice day, sweetheart.

Wow, more rude and stupid ignorance.

You still think half-life involves a substance disappearing???
And you're querying other people's educational background?

Any child with a basic understanding of science knows matter and energy do not just disappear.
The half-life of any substance is the time in which half of that substance transmutes into another substance.
This may be a different element, a different isotope of the same element, or the ground form of the element.
The energy given off by the decay into a daughter substance is the energy that is radiation.

Half-life is the time it takes for such transmutation to occur.

Half Life and Radioactive DecayHalf Life and Radioactive Decay

Transmutation describes a process by which the nucleus of a radioactive atom undergoes decay into an atom with a different number of protons, until such time as a stable nucleus is produced.

An alpha particle (i.e., a helium nucleus) is released during alpha decay of a radioactive substance. An element with a lower mass is formed. Mass is not conserved. Atomic mass number (or nucleon number, or baryon number) is conserved.

Beta decay (beta negative decay) occurs when a beta (negative) particle is released from the nucleus (i.e., electron). Mass is also not conserved in beta decay. Nucleon number is conserved. In beta decay, the beta particle released originated in the nucleus of the atom, not in the electron orbital. A neutron is lost, and in its place a proton and an electron are formed.

Gamma decay is the release of excess stored energy from the nucleus. No transmutation occurs. However, gamma decay often accompanies alpha and beta negative decay in a decay series. (The series of steps in the transmutations occurring until a stable nucleus results, is called a decay series.) Gamma decay occurs when an excited nucleus (excited by photon or particle bombardment, or it may be a decay product in an excited state) returns to the ground state. An excited nucleus is heavier than the ground state, by a mass equal to the mass/energy equivalent of the energy of the emitted gamma ray.

Each radioactive nuclide emits radioactivity at its characteristic rate, different from that of other nuclides. The rate of radioactive decay is related to the energy change that accompanies the transformation, but it is not a direct relationship. The rate of radioactive emissions of a radioactive nuclide is directly proportional to the amount of radioactive material present. The rate of decay of a radioactive nuclide is measured by its half-life. Half-life is the time required for one half of the atoms in any starting sample of a radioisotope to decay.

Get that yet?

"Half-life is the time required for one half of the atoms in any starting sample of a radioisotope to decay."
Transformation describes that decay.

Sooooo moving on.... has anyone found out if the claim that 'it' is 72,000 times Hiroshima true or rubbish? I saw something pop up on RT as I walked past the TV on their scroller that said China was reporting severely high radiation.. haven't had a chance to look it up yet though.

Originally posted by yzzyUK
Sooooo moving on.... has anyone found out if the claim that 'it' is 72,000 times Hiroshima true or rubbish? I saw something pop up on RT as I walked past the TV on their scroller that said China was reporting severely high radiation.. haven't had a chance to look it up yet though.

Any simple quantification of a comparison of complex events is rubbish. There are many different factors to consider.

On the one hand, we don't have ~100.000 people being suddenly blasted to death from Fukushima.
On the other hand, the Hiroshima bomb was an air blast which supposedly, (I'm sceptical,) did not drop nuclear fall-out over Hiroshima.

The Fukushima reactors each have a storage pool above them, right there in the same building, containing hundreds of spent fuel assemblies. Spent fuel from a reactor is even more deadly than fresh fuel as the fission process creates plutonium from uranium, so each spent uranium rod contains ~1% plutonium. Plutonium is thousands times more dangerous than uranium. To make things worse, at least one plant, No. 3, had MOX rods, made with 5-6% weapons-grade plutonium from decommissioned weapons, mixed in with the uranium during manufacture. There was no plutonium in the Hiroshima bomb.

With the external containment structures blown open, the spent rods are open to the atmosphere, and there have been fires burning over them, releasing huge amounts of radioactive particles into the environment. There also appear to be containment leaks in the cores. Prevailing winds from Fukushima have tended include Tokyo in their curved sweep out over the ocean, thus Tokyo may be experiencing fall-out on a scale Hiroshima did not.

Statistically, this is going to cause an increased cancer/death rate, the only question is how much. I'm still hoping the long-term effects in Tokyo won't be too serious.

The core of Little Boy contained 64 kg of uranium,

According to the latest TEPCO report, on the Dai-Ichi site there was 577 tons of fuel in reactors
+ 1840 tons in storage =
= 2417 tons

Therefore there is 37765 times more radioactive fuel, by weight, on the Fukushima Dai-Ichi plant as there was in the Hiroshima bomb. It would not be a stretch to say the addition of plutonium makes this at least twice as deadly as uranium. So that gets you close to the OP's figure of 72,000, except for the fact that much of this fuel will not be released into the environment.

The dangers from this disaster are great, and terrible harm has already been done to the surrounding area. However a general comparison to a tragedy like Hiroshima is not helpful, as they are completely different situations.

For a good article on the dangers of the spent fuel: Greater Danger Lies in Spent Fuel Than in Reactors

Originally posted by 00nunya00
reply to post by Kailassa

 

And since you're dependent on Wikipedia, here

Half-life is the period of time it takes for a substance undergoing decay to decrease by half.

A kind Mod helped me get back the important part of my deleted post:

As your quote says, Half-life is the period of time it takes for a substance undergoing decay to decrease by half.
The substance decreases by half because half of it changes to another substance!
Did you think matter or energy simply disappear?

Nothing just disappears in this world. Things can move, things can change, but matter+energy is a constant, as any basic physics text will tell you. Half life is not about substances disappearing. It's about entropy causing a substance in a higher energy state to change into a substance in a lower energy state. This is done by releasing energy, and that energy is radiation. After the energy is released, what's left of the substance the energy was released from is a new substance. It can be a new element, a new isotope or the ground state of the original isotope, depending on what the initial substance was.

For example, carbon-14 atom (the "parent") emits radiation (a beta particle, antineutrino, and a gamma ray) and transforms to a nitrogen-14 atom (the "daughter"). Technetium-99m decays by the emission of a gamma ray, to an atom of technetium-99.

Just as I illustrated by talking of the half-life of oranges leaving half, over that period of time, turning into lemons, the half lives of the various plutonium isotopes mean that in that time half turns into uranium or americium isotopes, depending on the initial isotope of plutonium.
Decay modes of plutonium isotopes

Strontium 90, a product of nuclear fission, has a half life of 28.8 years. 90Sr undergoes β− decay with decay energy of 0.546 MeV to an electron and the yttrium isotope 90Y, which in turn undergoes β− decay with half life of 64 hours and decay energy 2.28 MeV for beta particles to an electron and 90Zr (zirconium), which is stable.

If you can't understand that carbon-14 is a different substance to nitrogen-14, that plutonium is a different substance to uranium, or that strontium 90 is a different substance to zirconium, I guess no physics book is going to help you.