Should the atomic bombs have been dropped on Hiroshima and Nagasaki?

World War II General WWII Discussion
#341

I’m strongly doubt that the dust that was out of fireboll was not charged after the explosions. And i think the neitrons could easy irradiate the dust ( if even the neitron stream reached the suface in the radius of kilometer.)
Besides you foget that alstout the magiority of dust was sucket up in to the sky - nevereless LATER it fall down - charging the territory around the city.

To be precise the amount of material in that cloud is almost exactly equal to the amount of material in the weapon. A few tonnes spread out over several thousand square miles does not a health hazard make. The overwhelming majority of fallout risks come from ground-bursting hydrogen bombs, where up to 100,000 tonnes of earth could potentially be contained within the fireball. THAT is a health hazard.

It’s strange by the hudrogen bomb even more “clear” in some aspects.
For instance the U-235 bomb that was droppend in Japane was very uneffective ( only 1,8% of Uranium were participated in Reactin- the rest 92% simply fallout).

The difference is that it is possible to show by calculation that very few people will have suffered from radiation sickness due to Neutron/Gamma bombardment from the nuclear blast. Fallout is known to have been negligible (unless you accept the rather strange argument that one black and white photograph invalidates a decade of properly instrumented test data). That only leaves long term effects of the initial radiation (cancer, etc.) - and we simply don’t have any very good way of telling what the casualties from that are. As an example, back in the 1950s there was a major fire in the British nuclear reactor at Windscale, used to produce plutonium for the British nuclear weapons project. Estimates for the long term deaths from that event vary between zero and 20,000. It should be noted at this point that last I heard one of the men who climbed inside the reactor to fight the fire was still alive and healthy in his 80s last I head.

Well i’m too still do not see the confirmationof the “low radiation fallout” except the “manies testing in Navada”.
Do you really want to say the readoation level in the Hirosima was quite normal after the Bombing?
And all of the over 200 000 of victims died from Mostly the neitron/gamma irradiation?

If not, post a link to or otherwise identify the paper when they made this claim. Numbers like that do not fit with my knowledge of nuclear engineering or with the textbooks to which I have access. I note also that you STILL haven’t posted any information about where you got those numbers from. When you get implausible and unsourced figures cropping up, they have to be treated as suspect.

It’s strange pdf do you really think i will spread a noncence about Hirosima?
http://www.nuclearno.ru/text.asp?9990

Monument to the victims of Hiroshima - gray concrete tent. Inside the monument - lime plate, under it - casket with the names of the victims of bombardment - Khibakyshi In 2003 in it almost 227 thousand people was registered.
About 140 thousand of them perished during the explosion or into first yr after it, and in the beginning of June 2004 this list supplemented two American soldiers - 19-year Norman brissett from the state of Massachusetts and 20-year Dzhulius Of molnar from Michigan, find in the Japanese captivity. The first died in two weeks, and the fate of the second so remained unknown. Until now in the number of officially mentioned victims of bombing was registered only three soldiers OF THE USA. In 2004 to the foot of monument to the victims of tragedy lay the list with the names of 5.142 additional people, who, according to the official statistics, died in the past year of the diseases, connected with the consequences of bombardment. Thus, the total number of victims of the tragedy in Hiroshima of steel of 237 062 people

And this is ONLY in Horosima in 2005 . today this figure is more over 6 - 8 000 of peoples.
[/quote]
So again, you’re assuming without anything beyond anecdotal evidence that a properly conducted study is wrong. There are one hell of a lot of causes of cancer and related diseases, but with incidents like Chernobyl people will always take the opportunity to blame the incident for their illness. The human mind does not like attributing suffering they experience to random chance - it is always easier to blame someone else.[/QUOTE]
wHen did i say it was a incident of her ilness?
As i’ve showed you the Ukrain datas - about 18 000 of peoples - who died fom the consequences of Chernobul.
However there is a great figure of people( About 30 000) who still alive but ill by the cancer and ets.

#342

Purely and simply because it amused me to do so. There are far too many people out there for whom radiation = instant death, and it’s always fun to provide examples like that to wind them up.
(Yes of course I know anecdotal evidence means nothing, but it does occasionally bring home a point in a way statistics don’t for some people.)

To be exact it falls down out of the sky downwind. And about the only thing downwind from Hiroshima and Nagasaki is the Pacific Ocean…

Umm… you’ve got that the wrong way around. U-235 metal is actually very safe apart from some slight heavy metal toxicity - it’s a low-level alpha emitter with a half life of 700 million years. That means that there is a 50% probability that any given U-235 nucleus will emit an alpha particle in any given 700 million year time slot.
Very little of the Uranium which participates in the reaction however is destroyed. When Uranium fissions, the mass is reduced slightly (releasing energy - the equation E=mc^2 comes in here). An average of 2.5 neutrons is also released, and the remaining mass of the U-235 atom splits roughly in two. This gives a range of elements with mass numbers of around 100-150. However, because they have the wrong number of neutrons within them, they are also highly radioactive. This stuff is what the nuclear waste from reactors is composed of, and in large quantities it’s pretty nasty. Most sources agree that the total mass of material which underwent fission in the two bombs was less than 1kg. Hence, there would be around 1.5kg of highly radioactive material from the two weapons spread out over thousands of square miles (most of it ocean). It would pretty much be diluted into insignificance.

#343

Ummm… that site only states the number of names on a memorial. Quite frankly I suspect that before very long it will contain the names of just about everyone who was in Hiroshima at the time. That is NOT evidence that the bombing had anything to do with their death.

Ummm… you provided an article which said one ministry in the Ukraine had the figure of 18,000 or so and that the UN figure (actually IAEA - not quite the same thing) was around 4,000. The rest of the article went on to describe how environmental pressure groups were trying to inflate the figure as much as possible to support their campaign against new nuclear power stations. That is NOT the same thing as evidence.

#344

Waging wars of aggression appears to have been more widely accepted in the 1800s than in the 1900s. Perhaps Japan would be veiwed differently had it been rampaging in the 19th century rather than the 20th century due to many other countries behaving in similar manner. The imperialist conquests of the European nations during this period seem like a good example.

#345

To be exact - you absolutly could no know where the most of radioactive fallout goes in Horosima. True the most of LIGHT charged dust coudl migrated far from adistance of the handreds kilometres , charging the territory.
However this is not right for the HEAVY fallout ( like the products of the explosions and the pieces of lands that were lifted up in initial momen.
This fallout fall near the place of bombing.

Umm… you’ve got that the wrong way around. U-235 metal is actually very safe apart from some slight heavy metal toxicity - it’s a low-level alpha emitter with a half life of 700 million years. That means that there is a 50% probability that any given U-235 nucleus will emit an alpha particle in any given 700 million year time slot.
Very little of the Uranium which participates in the reaction however is destroyed. When Uranium fissions, the mass is reduced slightly (releasing energy - the equation E=mc^2 comes in here). An average of 2.5 neutrons is also released, and the remaining mass of the U-235 atom splits roughly in two. This gives a range of elements with mass numbers of around 100-150. However, because they have the wrong number of neutrons within them, they are also highly radioactive. This stuff is what the nuclear waste from reactors is composed of, and in large quantities it’s pretty nasty. Most sources agree that the total mass of material which underwent fission in the two bombs was less than 1kg. Hence, there would be around 1.5kg of highly radioactive material from the two weapons spread out over thousands of square miles (most of it ocean). It would pretty much be diluted into insignificance.

Well i did not want to repeat the Nuclear Phisycs , but it seems i have to .:slight_smile:
Really ONLY 1,5 kg of higly Radioactime material was realised formt two bombs?
Well read the wiki

http://en.wikipedia.org/wiki/Little_Boy
The Mk I “Little Boy” was 10 feet (3 m) in length, 28 inches (71 cm) in diameter and weighed 8,900 lb (4000 kg). The design used the gun method to explosively force a hollow sub-critical mass of uranium-235 and a solid target spike together into a super-critical mass, initiating a nuclear chain reaction. This was accomplished by simply shooting one piece of the uranium onto the other by means of chemical explosives. It contained 64 kg of uranium, of which 0.7 kg underwent nuclear fission, and of this mass only 0.6 g became energy.

i.e from the 64 kg uranium-235 desintegrated ONLY 700 gramms.
So the overal mass of fassion is close to the 1 killogram.
AND WHERE dissapeared the REST 63 kg of Uranium-235 - convert to the sugar;)
No this is FALLOUT and highly radiioactive;)
Being the very heavy metal the Uran-235 simply unable to fly far with the other fallout and fall IN THE NEARES areas of the Nuclear explosions.
Thus the territory about few square kilometred covered of the 63 kg of Uran-235 - very high dose that coude cause the sicknees of the peoples who has visited the AREA of bombing through the long time ( as you 've already mentioned the half-life of U-235 is 700 millions years).
Therefore as it was proved by the statistical datas in Hirosima- the many peoples who works in the liqudatation and rebuildings in there after the war has got the doses of radiation and as resault - ray’s sickness.
So using the scientic methods do not forget about other factors;)

Cheers.

#346

<bangs head against a wall> I’m getting flashbacks of Ironman here Chevan.

U-235 is NOT highly radioactive. Frankly, provided that it didn’t get turned to dust or reach critical mass (and my floor was strong enough) I would be quite happy to use it as furniture. It’s an alpha emitter with a half life of 700 million years (and remember, alpha particles can be stopped by a sheet of paper - so this stuff is only capable of causing harm if inhaled).

The highly radioactive stuff is the fission products from the chain reaction. Quoting from your wiki again:

Where exactly did you think the 0.7kg which underwent fission (and so was no longer Uranium) went? Only 0.6g was turned into energy, the rest is in the Neutrons and decay products released. These decay products are HIGHLY radioactive, and some of them like Iodine 131 are preferentially absorbed into the Thyroid for example. Hence after a nuclear accident about the first thing handed out are Iodine tablets - this tops the thyroid up with the maximum amount of Iodine it can take so the Iodine-131 isn’t absorbed.

#347

Really the U-235 is so safe as you try to tell?
And what is the criteriy of radioactivity?
Could you show the comparition for us the U-235 with for instance Thorum-231?

Frankly, provided that it didn’t get turned to dust or reach critical mass (and my floor was strong enough) I would be quite happy to use it as furniture.

Ha Ha u-235 as furniture;)
Well good luck to use.
Just remember that we will misses for you in here;)

#348

Chevan, a half life of 700 million years means that it is really not very radioactive at all. As a comparison, carbon 14 (of which there is plenty in your body) is 122164 times as radioactive, with its half life of 5730 years.

If you think that a half life of 700 million years means that a substance is highly radioactive, then you do not understand basic physics.

#349

Yep. U-238 has a half life of 4,500 million years while U-235 has a half life of 700 million years, so U-238 is perhaps 6 times more radioactive. We were using a lump of U-238 as a doorstop in my old engineering department for 20 years before anybody noticed. And the only way they found out was to weigh it and work out it’s density - unless experiencing neutron bombardment Uranium does not give out easily measured levels of radioactivity - indeed the chances are the levels given out are at or below background radiation in most cases.

Thorium-231 has a half life of 25.5 hours. Hence, Thorium-231 is 240,470,000,000 times more radioactive than U-235 (yes, that’s right, 240 billion). Furthermore, it is a beta emitter which means the radiation it emits is marginally more penetrating than that emitted by U-235.
Half life is defined as the time it takes for half of the particles present to decay and give off a radioactive particle (alpha, beta, gamma or neutron). Thorium-231 has a half life of 25.5 hours so is in radioactive terms red hot - I wouldn’t want to handle the stuff at all in any quantity without using a glove box and manipulator arms. U-235 has a half life of 700 million years so provided critical mass isn’t reached the biggest hazard is dropping it on your toes (seriously - Uranium is an extremely dense metal).

Provided you don’t have a criticality accident it’s totally safe. U-238 as mentioned above has a very similar half life but doesn’t have the criticality risk. With furniture made from that the only danger is it going through the floorboards.

#350

Well lets struding the Nuclear phisycs together with pdf guys;)

The fission reaction in U-235 produces fission products such as Ba, Kr, Sr, Cs, I and Xe with atomic masses distributed around 95 and 135. Examples may be given of typical reaction products, such as:

U-235 + n ===> Ba-144 + Kr-90 + 2n + energy

U-235 + n ===> Ba-141 + Kr-92 + 3n + 170 MeV

U-235 + n ===> Te-139 + Zr-94 + 3n + 197 MeV

All the elements Ba, Kr,Sr Cs, I and Xe are highly radioactive as told us the our friend pdf.
But those elements have the GREAT mass- they much MORE heavy then the Lead-82.
Thus MOST of those element fall out to the surface NOT FAR fron the Centre of Explosion.
Coz in differ form the easy dust - this couln not travel for the thousands of kilometres.
Besides there is no the essential wind in Hiroshima at that day - thus MOST of the 600 grams of extremay danger Rdioactive products fall down in the area NO MORE the several squear kilometres.
But not the THOUSANDS SQUARE MILES as our pdf think;)
The fact of danger radiation near the epicenter aslo was comfirmed the many of tesimoties and statistical datas of death-cases
For instance:

After the explosion in Hiroshima 250 militiamen, who arrived from the adjacent village, and worked on clearing of obstructions in 600 meters from the epicentre.
Not it was them in the city at the moment of explosion, but they all obtained lethal radiation dose. The fact is that besides that isolating first seconds of the flow of gamma-rays, fatal danger created the induced radiation, radiated by the products of explosion and by the infected soil.

“Hirosima: 40 year after.” Yerish A.I. 1970.

So as we could say from the documental evidences - EVEN IN DISTANCE of 600 metres from epicentre the RADIATION level was still MORTAL for the peoples.

P.S.May be someone else want to prove us that the Little boy bomb was so “safe” for the Japs and the radiation background was TOO unsignificant after the bombing ?

#351

yes yes you right sure.
U-235 is much more stable than the others.
The main reason of hight radiation background was the soil irradiated by the power stream of neutrons during the explosion.
Not U-235, my mistake.
But does it meain this absolutly safe?

#352

At work now so don’t have my references to hand, and off with the Army tonight. I’ll try and crunch some numbers to see if the ground was subjected to enough of a neutron flux to do that later in the week (maybe wednesday night), but I rather suspect it won’t have been. Certainly I have yet to see any particularly believable data to suggest that the background radiation in either city has increased due to the bombings.

One thing to remember is that Japan is a very volcanic country, so has a lot of granite rock about. Granite contains a fair amount of Uranium-238, and one of the decay products of Uranium is Radon gas. Radon has a short half life (just under 4 days) and what is worse can easily be breathed in. Some granite rock structures have cracks in them, and if a poorly ventilated house is built on these then the inhabitants can effectively be living in a cloud of Radon gas. This in turn will knock the background radiation level way, way up.

I would be totally relaxed about living and working with Uranium in small enough quantities that a criticality accident is not a risk. While there is no such thing as absolutely safe, the risks involved are too small to measure accurately. The biggest risk is IMHO Writer’s Cramp (the muscles in your hand being tired out) from dealing with all the paperwork involved in having anything “nuclear” in your possession.

#353

May i ask a question pdf?
How could we calculate the going out the neitron’s quantity that fly to the land under the fireboll?

#354

Best answer is to get a suitable textbook. The one I’ve got is called The Effects of Nuclear Weapons published by the US Department of Defence and the US Atomic Energy Commission in the 1960s. Some of them also have a Nuclear Weapon Effects Calculator in the back (my copy does).
From this, you’ll find the correct formula to calculate the number of neutrons given out by a particular size of bomb (won’t be exact for obvious reasons, but probably close enough).

As Neutrons travel in a straight line until they hit something, and air isn’t really dense enough to do anything to them then we can assume that for any given spherical surface centred on the bomb the same number of neutrons will be passing through it. Hence the number of neutrons going through any size of target will vary with (distance from the bomb)^3, and it is relatively easy to calculate the number of neutrons hitting any particular object.

Working out exactly what effect they will have on a target isn’t all that simple - not all neutrons will transmute what they hit into something else, and not everything transmuted will be radioactive. Again, this is something that you’ll have to get from the textbooks.

#355

Well now you agree that to calculate the real ( or at least rought ) strength of Neitrons strean i.e it very hadr to calculate theretically the level of irradiation of the objects> thus we could n’t know for sure this backgroung in Hiroshima, right.
But the neitrions is not only the particles that coudl charge the objects.
What’s about gamma-rays that charged the obgects as well as the neitrons?

#356

Not by calculation, but it is relatively easy to measure background levels out on the ground.

Neutrons are the only particles that can transmute one element into another. Alpha, Beta and Gamma radiation can ionise particles (knock electrons out of them causing them to become charged - this is why they cause biological damage) but they cannot change one element into another.

#357

So have the any realible datas of the experimental measuring of the nuclear testing of simular devices like the Little Boy.
In different distance from epicentre?

Neutrons are the only particles that can transmute one element into another. Alpha, Beta and Gamma radiation can ionise particles (knock electrons out of them causing them to become charged - this is why they cause biological damage) but they cannot change one element into another.

Well ok thanks pdf;)
The question about Gamma rays closed.

#358

I’ll check when I get back to my book (at work now, busy tonight).

#359

Excuse me if this has been mentioned already, but didn’t the US drop the bomb simply because they were becoming ‘war-weary’ it was very expensive in lives and money and they just wanted to bring an end to it with a weapon that had had a lot of money spent on it and, therefore, might as well be used to save further spending of lives and dollars and get on with building a better world?

#360

i think that if the two bombs weren’t dropped the war would continue for much time . the Japs were so fanatic that they would keep going with the fighting until the us infantry man captured tokyo or kill every single on jap (what was absolutelly impossible)