[Heiwa]

Excellent introduction to the Forum. Allow me to add some basic physical facts:

Uranium is a metal with density 18 950 kg/m3 when solid at 20°C and 17 907 kg/m3, when melting at 1132.4°C. It means, e.g. that a sphere of solid uranium at 20°C with diameter 0.1 m and volume 5.23E-4 m3 weighs 9.92 kg and with diameter 0.15 m weighs 33.49 kg. When heated the uranium sphere shrinks.

The relative atomic mass of uranium is about 238, which means that 238 gram of uranium is per definition one mole of uranium. Every mole of uranium contains about 6E23 atoms of uranium, we are told.
From above we can conclude that a solid sphere with diameter 10 cm contains about 41.68 mole of uranium or 2.5E25 atoms of uranium, i.e. plenty of uranium atoms.

Reason why so many uranium atoms can be pressed into a diameter 10 cm uranium sphere is that the atoms are very small.
It would appear that the volume of one uranium atom is of the order 5.23E-4/2.5E25 or 2.092E-29 m3 and that the radius of a uranium atom is about 1.7E-10 m or 3.2 times bigger than the Niels Bohr radius of a hydrogen atom, i.e. the distance of one electron from the proton core of a hydrogen atom. That radius is then >1000 times bigger than the radius of the atom proton core itself, which means that an atom volume is mostly vacuum or empty. Imagine that.

Why a uranium atom should be so much bigger in diameter as a hydrogen atom, is beyond my understanding. Maybe the electrons spin around a uranium atom core in layers at larger distances? One thing is certain—there are plenty uranium atoms in a 10 kg sphere of uranium.

We are furthermore told by historians that at about 8.15 hrs am on August 6 1945, an atomic bomb of uranium was dropped on Hiroshima, Japan, and exploded above the town at say 1 000 m height producing a lot of sudden damage. The bomb may have consisted of about 10 kg of uranium 235 that USA had managed to isolate. In order to explode the atomic uranium bomb, i.e. starting the chain reaction (sic), one uranium 235 atom core (there are 235 protons and neutrons in that core) was split into two parts (of say A and B protons/neutrons (A+B=235 minus the neutrons released) by one neutron and released two or three neutrons in the process. These two or three free neutrons then managed to collide with two or three other uranium protons cores (each consisting of 235 protons/neutrons) splitting them into more A and B atoms and releasing more free neutrons. Thus the chain reaction (sic) had started and in a few nanoseconds all 25 000 000 000 000 000 000 000 000 atoms in the 10 kg uranium 235 bomb had been split into A and B atoms + plenty of free neutrons releasing pure energy equivalent of 10 000 tons of TNT, we are told. In nanoseconds a diameter 6-7 kilometer Ground Zero (28-38 square kilometer) was created and everything there was blown away. The free energy released heated and compressed the air to millions of °C and atmospheric pressures and the heat/pressure wave destroyed everything in its way.

Niels Bohr tried to explain how a uranium 235 atom could be split into A and B atoms releasing neutrons and pure energy but the explanation—the 235 atom assembly of protons and neutrons starts to vibrate and splits into two (??)—is not convincing. In 1942 Niels Bohr stayed overnight at my mother’s house outside Stockholm on his way to USA. She forgot to ask him if a chain reaction was really possible. Niels forgot a piece of luggage at my mother's place.

A friend of mine, C C-B, arrived at Yokohama, Japan in September 1945 and tried to visit Hiroshima but the area was forbidden to enter. I arrived at Yokohama in 1971 and visited both Nagasaki and Hiroshima. Little evidence of atomic destruction there, I have to say.

It would appear that Hiroshima was simply saturation bombed by 600 B29s using napalm in the night 5/6 August (as Hiroshima in the night 8/9 August). Later, after total napalm destructions burning down the towns, maybe a magnesium bomb was ignited in the morning to produce a FLASH that witnesses could tell about. Why pure energy of an impossible chain reaction would produce a dirty mushroom cloud is also not possible. The whole show was a psy-op to force Japan to quickly surrender and allow USA to occupy Japan (in lieu of USSR that attacked on August 10). Carpet bombing towns had been learnt and practiced over Dresden, Saxony, in February 1945 and Tokyo and Yokohama in March 1945 (and other Japanese towns).
That a chain reaction producing an atomic bomb is not possible is easy to understand. As soon as one uranium atom in a 10 kg sphere of uranium 235 is split into A and B and releases neutrons and free energy, the sphere simply melts and drops through the container that holds it. The free neutrons just fly away and miss most of the other uranium atoms in the liquid. To keep a nuclear reaction going you have to do it in a nuclear power station (and cool the uranium all the time to avoid a Fukushima accident). That all 25 000 000 000 000 000 000 000 000 atoms in a 10 kg uranium 235 bomb can be split during a few nanoseconds is just a stupid fairy tale.

[rerevisionist]

Heiwa, welcome! You must presumably be Swedish - thanks for the anecdotes; you must also be rather elderly!

I wonder if you'd care to translate, summarise, edit or write anew, in Swedish, some of the points made in this site? Add them to the new section at the end. And suggest a title - maybe 'nuke lies' in Swedish.
____________
I hope you don't mind being moved from the Introduction, which I'm pleased you liked, to this section, where it's more likely you'll be findable.

NB on the physics, I'd be happier if you gave some consideration of the mean path that neutrons would have to travel, and the time it would take. I can see that a defender of the theory could say that melting takes a finite time, so the uranium could split up in such a short time that it wouldn't have time to physically change shape. It could be a bit like a balloon, containing water, that is popped - for a short time the water remains in a ball.

[Heiwa]

Hallo rere! After spending 1971/76 in Japan I moved to southern France in 1978 where I remain until today. Only my mother remains up in the cold. The house where Niels Bohr slept a few nights in 1942 belongs nowadays to my cousin.

We are told that the diameter of one neutron or proton is of the order 1.6E-15 m, so a uranium atom core with 238 or 235 protons/neutrons held together by various forces in some sphere or ball shaped configuration must have a much greater diameter, say of the order 1.4E-14 m. Assuming that the radius of a uranium atom is 1.7E-10 m, i.e. the distance between core protons/neutrons and outermost electrons, then the distance between two uranium atom cores is minimum 3.4E-10 m or about 25 000 times the diameter of the core.

When a uranium atom core of 235 protons/neutrons is split into two parts A and B (in a bomb to start a thermonuclear war!) and releases two or three free neutrons (the number of neutrons/protons of A and B plus the two or three free neutrons always adding up to 235 in this awful case) and energy, the free neutrons must displace the distance 3.4E-10 m or 212 000 times their own diameters to contact the nearest intact uranium atom core. It is relatively speaking a long path or way. As the velocity of the neutron is not known, we do not know the time it takes to move from the first split uranium core to the nearest intact uranium core.

The probability that a free neutron (with diameter 1.6E-15 m) shall hit the nearest uranium core 3.4E-10 m away is very small due to the fact that the neutron has very small diameter and that the nearest intact uranium atom core is 212 000 neutron diameters away. Of course there are plenty of intact uranium atom cores in a 10 kg ball of uranium (2.5E25 to be exact) so it seems one free neutron will actually collide with another intact uranium atom core somewhere and split it one way or another and release more neutrons and energy. But that path may be another 100 000 times longer than the shortest path.

Therefore, that all 2.5E25 uranium 235 cores in the 10 kg uranium ball will split in some nanoseconds seem impossible.

The energy (J) released when splitting one uranium atom core apart into A and B atoms is apparently the force (N) that holds A and B together forming the uranium atom times the distance (m) it takes to move A and B apart. What shape that energy takes is not clear to me but I assume it will finally heat up our 10 kg uranium ball and melt it.

This is what happens in nuclear power plants all the time except that nothing melts - only the cooling media is heated.

[FirstClassSkeptic]

It would appear that Hiroshima was simply saturation bombed by 600 B29s using napalm in the night 5/6 August (as Hiroshima in the night 8/9 August). Later, after total napalm destructions burning down the towns, maybe a magnesium bomb was ignited in the morning to produce a FLASH that witnesses could tell about.

Interesting. Hadn't thought that maybe Hiroshima was bombed at night. I can't think of anything I have ever read that told about what happened the night before. They talk about people getting up in the morning like it was a usual day.

There's a thread somewhere on here about photoflash bombs.

[Ranb]

Excellent introduction to the Forum. Allow me to add some basic physical facts:

Thus the chain reaction (sic) had started and in a few nanoseconds all 25 000 000 000 000 000 000 000 000 atoms in the 10 kg uranium 235 bomb had been split into A and B atoms + plenty of free neutrons releasing pure energy equivalent of 10 000 tons of TNT, we are told. In nanoseconds a diameter 6-7 kilometer Ground Zero (28-38 square kilometer) was created and everything there was blown away. The free energy released heated and compressed the air to millions of °C and atmospheric pressures and the heat/pressure wave destroyed everything in its way.

That a chain reaction producing an atomic bomb is not possible is easy to understand. As soon as one uranium atom in a 10 kg sphere of uranium 235 is split into A and B and releases neutrons and free energy, the sphere simply melts and drops through the container that holds it.

That all 25 000 000 000 000 000 000 000 000 atoms in a 10 kg uranium 235 bomb can be split during a few nanoseconds is just a stupid fairy tale.

I was not aware that any of the early nuclear bombs were so efficient as to split every uranium atom in the core. What is your source for this information? As far as I know less than 1 kg of the 64 kg uranium load actually fission. The gun barrel type of uranium fission bomb was not very efficient.

So how much energy does the fission of one uranium atom generate? Is this enough to melt a 140 pound block of metal? Of course not. Care to show us the math you used to come up with claim?

I do agree that anyone claiming 100% fission in a gun barrel type fission bomb is telling a fairy tale. Most of the rest of your post I do not agree with at all either.

Ranb

[Heiwa]

AA. I was not aware that any of the early nuclear bombs were so efficient as to split every uranium atom in the core. What is your source for this information? As far as I know less than 1 kg of the 64 kg uranium load actually fission. The gun barrel type of uranium fission bomb was not very efficient.

BB. So how much energy does the fission of one uranium atom generate?

CC.Is this enough to melt a 140 pound block of metal? Of course not.

DD. Care to show us the math you used to come up with claim?

I do agree that anyone claiming 100% fission in a gun barrel type fission bomb is telling a fairy tale. Most of the rest of your post I do not agree with at all either.

Ranb

AA. So 2.5E24 uranium atoms (1 kg) in a 64 kg bomb fission. What is your source for that info?

BB. When one uranium atom is split into two smaller atoms A and B by a colliding neutron, the energy (J or Nm) released is the force (N) holding A and B together times the distance (m) required to do the split.

CC. Maybe that energy becomes a FLASH and flies away and melts nothing. Melting steel,silver and gold ... and uranium is otherwise quite easy. Just heat them up!

DD. 1+1=2

[Ranb]

There is info all over the internet on atomic bomb specs. Try here. http://nuclearweaponarchive.org/Nwfaq/N ... #nfaq8.1.3

What did you mean by this statement?

As soon as one uranium atom in a 10 kg sphere of uranium 235 is split into A and B and releases neutrons and free energy, the sphere simply melts and drops through the container that holds it.

Are you claiming that uranium can melt and drop down faster than neutrons can interact with it at prompt speeds?

Instead of 1+1=2, maybe you should be calculating the increase in binding energy of the fission fragments to determine how much energy is released from fission and how many fissions are required to melt a 64 kg piece or uranium.

Ranb

[Heiwa]

There is info all over the internet on atomic bomb specs. Try here. http://nuclearweaponarchive.org/Nwfaq/N ... #nfaq8.1.3

What did you mean by this statement?

As soon as one uranium atom in a 10 kg sphere of uranium 235 is split into A and B and releases neutrons and free energy, the sphere simply melts and drops through the container that holds it.

Are you claiming that uranium can melt and drop down faster than neutrons can interact with it at prompt speeds?

Instead of 1+1=2, maybe you should be calculating the increase in binding energy of the fission fragments to determine how much energy is released from fission and how many fissions are required to melt a 64 kg piece or uranium.

Ranb

If the uranium (actually uranium oxide) elements in a power plant are not cooled at fission, they melt and drop throught the bottom of the power plant, cfr Fukushima. Same should happen in an atomic bomb! Luckily no atomic bombs exist! They are as real as Father Christmas and the Tooth Fairy.

[Ranb]

So you are claiming that fission neutrons and the other nuclear processes in fission are so slow that the bomb core will have time to melt and drop down? How do you come up with this stuff?

Do you understand the difference between prompt and delayed neutrons? While a bomb can supply enough prompt neurons to fission very quickly, a power plant reactor depends on delayed neutrons to stay critical. This limits how fast power changes and enables manual control of power either by rod position or steam flow depending on the power level.

Ranb

[Heiwa]

AA. So you are claiming that fission neutrons and the other nuclear processes in fission are so slow that the bomb core will have time to melt and drop down? How do you come up with this stuff?

BB. Do you understand the difference between prompt and delayed neutrons? While a bomb can supply enough prompt neurons to fission very quickly, a power plant reactor depends on delayed neutrons to stay critical. This limits how fast power changes and enables manual control of power either by rod position or steam flow depending on the power level.

Ranb

AA. Yes, that's why an atomic bomb doesn't work. Only atomic power plants work, e.g. in nuclear submarines.
BB. No, pls tell me the difference between prompt and delayed neutrons ... and their velocities. I thought there was only one type of neutron in e.g. an uranium atom.

[Ranb]

Prompt neutrons are emitted as a result of fission. Delayed neutrons are typically from beta decay and appear milliseconds or several seconds later. A delayed neutron has about 400 keV of energy.

What do you mean by type of neutron? I have previously explained that neutrons differ by energy level and source, what are you getting at?

Ranb

[Heiwa]

Prompt neutrons are emitted as a result of fission. Delayed neutrons are typically from beta decay and appear milliseconds or several seconds later. A delayed neutron has about 400 keV of energy.

What do you mean by type of neutron? I have previously explained that neutrons differ by energy level and source, what are you getting at?

Ranb

??? No neutrons are released by beta decay. Only electrons or similar. Another mistake?