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Whilst the commonly cited figure at Wikipedia is 64 Kg (141 lbs), the actual figure is 56 kilograms of 80% enriched Uranium 235, as cited in "The Last Mission, The Secret History of World War Two's Final Mission," published 2002 by Jim Smith and Malcolm McConnell giving the story of B-29 missions in the final days of WW2.
In contrast with:
http://en.wikipedia.org/wiki/Little_boy
The Quantity used was to ensure achieving natural critical mass, which falls in a range from 52 kilograms to 64 kilograms.
Various factors affect what determines natural critical mass such as:
Warhead temperature (cooler the better)
Density of fissile material
Geometry of the Warhead (spherical is smallest mass)
Isotope Purity
Neutron Flux & Uniformity
Use of Reflectors (ie containment of stray neutrons)
Of the 56 kilogram warhead of Little Boy which exploded over Hiroshima, only 780 grams or so exploded at the very heart of the Uranium sphere, or about 1-2% of the mass. That is because Neutron flux only attained criticality at the very heart of the sphere and not at the extremities where the Uranium 235 was wasted. When you increase efficiency of the Neutron Flux you require less fissile material. This is the key to shrinking a nuclear warhead.
In terms of the Hiroshima bomb however, 640 kilograms of un-enriched Uranium Oxide needed to be enriched to 80% 235U for a single weapon.
Uranium 235 is almost never used for nuclear weapons now. Pakistan still uses Uranium for it's warheads. Almost everywhere else now Plutonium is favoured for it's fail safe features.
Plutonium is harvested in a nuclear reactor by the radioactive bombardment of fuel which is enriched to 20% Uranium 235. The remaining Uranium 238 is converted to Neptunium 239 and then decays to Plutonium 239. The Plutonium is harvested by chemical separation from nuclear waste.
Only about 40 kilograms of un-enriched Uranium Oxide is required to obtain enough Plutonium via a heavy water nuclear reactor for a Plutonium weapon.
Wiki User
∙ 12y ago
Wiki User
∙ 13y agoIf you mean explosive yield, the Little Boy bomb detonated over Shima Surgical Clinic in Hiroshima with the force of 13 to 18 thousand tons of TNT.
The Fat Man bomb detonated over Nagasaki with the force of 21 thousand tons of TNT.
Wiki User
∙ 12y agoRoughly 1% to 2% of the amount used. Assuming a yield of 15KTons (the usual figure published), 787 grams fissioned. The bomb contained from 39.3 Kg to 78.7 Kg of Uranium. It was a very inefficient bomb. It was only about 80% enriched Uranium-235. If it had been an implosion bomb instead of a gun bomb, it would have been about 10% efficient and only needed 7.87 Kg of Uranium for the same yield.
Wiki User
∙ 11y agoLittle Boy had about 100 pounds of uranium, but only about 1 pound of that fissioned. The other 99 pounds were just vaporized and on cooling combined with oxygen to make uranium oxide dust in the fallout.
Wiki User
∙ 14y agoLittle Boy, the bomb dropped on Hiroshima, used 64.1 kgs of enriched uranium.
Wiki User
∙ 13y agoFor the first atomic bomb (Little boy, 1945) - 64 kg uranium.
Wiki User
∙ 14y ago64 kg uranium, highly enriched in U-235
Wiki User
∙ 14y agoOnly 64 kg of highly enriched uranium
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How much did the bomb Enola Gay weight?
The Enola Gay, the plane that dropped the atomic bomb on Hiroshima in World War II, weighed around 65,000 pounds (29,500 kilograms) when it dropped the bomb.
How much powerful is the thermonuclear bomb than the first atomic bomb named little boy?
This was an 11 mega ton weapon compared to the 16 kilo ton weapon used in Hiroshima.
How much money was wasted on the atomic bomb dropped in japan?
It cost $20,000,000,000 to build the 4,680 bombs in 1945. Two of them were the ones dropped over Hiroshima and Nagasaki.
What was the name of the atomic bombs?
Nobody. They were called Fatman (the Plutonium implosion MK-III bomb) and Little Boy (the Uranium gun MK-I bomb) because of their shapes. There is some mythology that the codenames Little Boy was named after FDR and Fatman was named after Winston Churchill to mislead spies into thinking that the "Silverplate" modified B-29s were being modified to transport those leaders, not a new type of bomb. But this is contradicted by the codename Thin Man (the Plutonium gun MK-II bomb) whose design was canceled before beginning work on the Fatman design. Thin Man would have fit FDR much better than Little Boy did and Little Boy could not have been named for Winston Churchill.
How much people die from an atomic bomb in a minute?
Probably nil. There have only been two atomic bomb launches on actual cities (in WWII, on Hiroshima and Nagasaki) that killed millions of people BACK THEN. But now, the radiation probably faded away, and thus causes no more deaths.
Did the radiation improve in Hiroshima and Nagasaki after the atomic bomb?
Yes, the radiation was much more abundant after the atomic bomb.
Atomic bomb in hiroshima?
ya because of atomic so much of people and childs could be died.And country spoiled
What was japan like after the atomic bomb?
Very much the same as before, except in Hiroshima & Nagasaki where the two bombs were dropped.
How much did the bomb Enola Gay weight?
The Enola Gay, the plane that dropped the atomic bomb on Hiroshima in World War II, weighed around 65,000 pounds (29,500 kilograms) when it dropped the bomb.
How much metal was in the Hiroshima bomb?
About 10,000 pounds. However, only 141 lbs of that was Uranium 235. Only about 1% if the U-235 underwent a chain reaction.
The first atomic bomb leveled approximately square miles.?
the first atomic bomb leveled nothing. That was exploded at the Trinity test site. The first bomb used in war was at Hiroshima Japan, and pretty much destroyed everything in a 3 mile radius. That is just over 7 square miles.
How much is a leaflet worth warning of atomic bomb being dropped on japan?
It is worthless because it is a fake. There were no leaflets warnings of the atomic bomb drops. After the bomb was dropped, Truman was quoted on a leaflet as saying that the USA had atomic bombs. I repeat, "AFTER." There were bomb warning leaflets that mentioned cities that might be bombed, but Hiroshima and Nagasaki were never mentioned and the atomic bomb was still such a secret that its name was never even whispered.
Where were the first nuclear bombs dropped?
A nuclear bomb has never been dropped. It was an atomic bomb that was dropped on the Japanese cities Hiroshima ans Nagasaki. An atomic bomb is a nuclear weapon. Nuclear bombs have much more impact than atomic bombs, and could potentially end the World if a nuclear war was started.
How much powerful is the thermonuclear bomb than the first atomic bomb named little boy?
This was an 11 mega ton weapon compared to the 16 kilo ton weapon used in Hiroshima.
Why is the atomic bomb called Fat Man and Little Boy?
The difference was little boy was droped on Hiroshima in world war 2, it is much smaller than the fat man used on Nagasaki and the little boy uses uranium to compress it. The fat man uses plutonium to detonate.
How much money was wasted on the atomic bomb dropped in japan?
It cost $20,000,000,000 to build the 4,680 bombs in 1945. Two of them were the ones dropped over Hiroshima and Nagasaki.
How many kilograms of Uranium-238 did the bombs dropped on Hiroshima and Nagasaki each contain?
None. The first atomic bomb was made with enriched uranium. Note: There is a "slight technicality" with this one. Here's the deal. Any time that a small quantity (or a slightly larger quantity) of uranium is found, either in nature or in the physics lab, there will be a tiny bit of plutonium in the sample. Only the tiniest bit, but it will be there. Uranium's isotopes are all unstable, and they will decay by spontaneous fission or alpha emission. Within that decay environment, a few atoms of uranium are transformed into atoms of plutonium. As stated, it's a "technicality" as such, but it's a fact.
