Trinity bomb test yields 0.5 kT

Hi!

Consider the following POD. During the countdown to the detonation of the Trinity device, a wire breaks or suffers some kind of damage after all the circuits are tested. This causes the device's yield to drop from OTL's 20 kT to 0.5 kT.

The scientist flip the switch and there's a big boom much larger than that of any bomb exploded before. Clearly, a yield like this could never have been reached without splitting the atom. The Manhattan Project has paid off.

Or has it?

Think about it from the perspective of one of the scientists on the site. The physicists are guessing that the device will yield 20 kT. However, it actually yielded only 500 T. No one has ever detonated a device like this before, so are no other tests or bomb designs to compare this against. The scientist therefore has no way to tell if the yield was lower because (a) the physicists messed something up in their calculation and you're supposed to get 500 T, or (b) the device malfunctioned and fizzled. The device has been completely destroyed in the blast, so there is no way to look at the evidence.

If the authorities start assuming the former, things get interesting. The government spent so much money on the Manhattan Project that they'll be very pissed if they only get 500 T out of their new weapon. What use is splitting the atom if it only gets you roughly the same yield as a typical bombing run? In a situation like this, putting all of your yield in one device could be a recipe for disaster if the aircraft carrying the bomb is shot down or the device malfunctions. The government concludes that nuclear devices are only worth it if you get 10 kT or more out of them. And since we only got 500 T despite all of the assurances of the scientists...

Here is what I foresee happening. The people at Alamogordo have only two more devices left. They can't risk detonating another one to double check physics for several reasons:
(a) if the yield is still 500 T they've not only seemed to confirm the theory that the physicists were wrong but they've lost a potentially powerful bomb to boot (albeit one which is not as powerful as they hoped),
(b) even if they get a 20 kT blast that only leaves one device to drop on the Japanese, something the enemy could conclude was a one-shot deal, and
(c) the greater the possibility that a Japanese spy or someone like that can see the blast and warn the Japanese that the Americans have a new weapon -- to the point where a Japanese defender may be willing to fire on a single aircraft if he thinks the aircraft is carrying a WMD (imagine what would have happened had antiaircraft fire taken out either Enola Gay or that bomb parachuting down).

I can imagine the deployment of the two remaining bombs delayed long enough to force the Americans to start invading the Japanese islands (Olympic, was it?). With American troops on the islands, the risk of using WMD's to destroy things risks hundreds, if not thousands, of friendly fire casualties. Considering that Olympic would probably been VERY unpopular anyway (given the possibility of a stalemate and high casualties on both sides), large friendly fire casualty totals would get the populace even angrier at the government and lead to people complaining that the government is wasting their time on big bombs.

Now what happens to nuclear technology after the war? If the Americans don't detonate any bombs during the war, the Russians may be the first to detonate a 20 kT weapon (if the Russians still believe that 500 T blast was in fact a fizzle). Perhaps the Russians will take the lead in the Cold War (or win it). Perhaps nuclear technology doesn't go anywhere at all (at least for weaponry purposes). What would a Cold War without nukes have been like? Turned hot in Europe again with no major deterrents?

Any thoughts?

ACG
 
Consider the following POD.


ACGoldis,

Your POD is unworkable on every level. Not the least of it's many problems are that you seem to be unaware of what type of bomb was tested at Trinity, what type of bomb was used at Hiroshima, how both those types work, and how implausible it would be for a "broken wire" or other mechanical failure to cause a subcritical detonation in the Trinity device.

Trinity was a test of a fission "implosion" device that used plutonium. Hiroshima was a fission "gun" device that used an uranium. The physics of both bombs were unquestionable. The mechanics of the Hiroshima device was also unquestionable, so much so that the design didn't even need to be tested and the drop over Hiroshima was it's first (and ever) use.

The theory behind the mechanics of the Trinity (and Nagasaki) device did need to be tested however. Whether the complicated implosion sequence could be successfully implemented needed to be determined. If that implosion was even tens of thousandths of a second off in some manner, the device would not detonate, even in the less powerful detonation your POD presumes.

May I suggest you check Richard Rhode's The Making of the Atomic Bomb or Dark Sun? Both books contain an accessible recounting of the fission and fusion bomb programs with the fusion book, with the fusion focused Dark Sun recapping the fission program. The books neatly explain the various physics and engineering problems associated with each program in a manner understandable to the lay person.


Bill
 
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Even if the scenario was plausible (which I doubt it is), it would largely be a case of so what - the biggest difference - it might be a few weeks before Japan gets nuked (BTW that might give time for the Russians to get land perhaps in Northern Japan which could be an interesting political consequence).

They had 2 types of bombs in 1945, and they'd test the other type as well, especially if the first type didn't perform as expected.

Sooner or latter, they'd also test the same type again.

It's unlikely all of these would fail in the same strange way.
 
Didn't I see somewhere that the US had a 3rd bomb ready to go a few days after Nagasaki?(sp) But the Japanese surrendered before it could be dropped?
docfl
 
Didn't I see somewhere that the US had a 3rd bomb ready to go a few days after Nagasaki?(sp) But the Japanese surrendered before it could be dropped?
docfl

They had a third bomb ready to go for the third week of August, three more in production for September and another three more for October.

Even if by some magic ASB handwave the Trinity bomb fizzles, all that happens is that the nuclear attacks on Japan get delayed for a few weeks.

And that's worse case scenario.
 
Didn't I see somewhere that the US had a 3rd bomb ready to go a few days after Nagasaki?(sp) But the Japanese surrendered before it could be dropped?


Docfl,

Not exactly.

There was a third weapon on Tinian and others in the production pipeline, but Truman withdrew authorization to use the weapons after the Nagasaki bombing. It wasn't a matter of Japan surrendering before it could be used, it was a matter of it's use not being authorized.

To further expand on what SunilTanna wrote, the US had two bomb designs. One used uranium in a certain fashion and the other used plutonium in a different fashion.

The uranium bomb called "Little Boy" was used on Hiroshima and it contained something over 95% of the pure U-235 on the planet. The "Little Boy" design was so "simple" that its physics didn't need to be tested. The mechanical design for "Little Boy" was such a no-brainer that it wasn't even fully tested either.

The lack of U-235 and the great difficulties in producing it meant that plutonium was quickly selected for the other bombs because it could be produced in breeder reactors relatively easier and faster than U-235. The "Fat Man" plutonium design was tested at Trinity and not because the physics were somehow suspect. The physics for "Fat Man" were as much a given as those for "Little Boy". What needed to be tested was the "implosion" created by the electro-mechanical detonation system. That test was successful, so a "Fat Man" device was dropped on Nagasaki.

The weapon waiting on Tinian and the others in the production pipeline were all plutonium "Fat Man" type bombs too. Refining enough U-235 was such a bottleneck that the US would only build 3 or 4 more "Little Boy" type bombs and then only well after the war.

If the Trinity device had failed due to a wiring or design flaw as the OP suggested, the result would have not been a "smaller" explosion or even a sub-critical detonation. A Trinity failure would have simply meant that the firing circuit design would have been re-examined and re-designed. A failure at Trinity wouldn't have even delayed the Hiroshima bombing.

Bill
 
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ACGoldis,

Your POD is unworkable on every level.


Bill

In some respects, I agree with you. The idea of the Trinity device failing in this manner stretches credibility. However, the Mahattan Project scientists were in disgareement over what the actual yield of the weapon would be. So lets say that the fault is found and fixed and another bomb is tested with similar results. I think that when the government learns that dropping 10 or 20 of them in the same place is the same as dropping 5,000 to 10,000 tons of conventional explosives, I think they will still call the Manhattan Project as success. Just to put things in perspective, during Operation Millennium, Bomber Command dropped roughly 1,500 tons of ordnance on Cologne.
 
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However, the Mahattan Project scientists were in disgareement over what the actual yield of the weapon would be.


Mike,

Those "disagreements" were quibbles. The physics weren't in question, they weren't in disagreement over whether fission on a large scale would occur. What they had questions about was how much fission could occur before the same process separated the materials enough. Most of the estimates they argued about varied by less than an order of magnitude.

So lets say that the fault is found and fixed and another bomb is tested with similar results.

For that to occur, the physical laws of the universe would have to change.


Bill
 
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Michael Busch

Concur with Bill and Dr. What.

While it would be possible for the Trinity test to have slight timing errors in the detonator circuits that stopped the shockwaves from the C4 lenses from properly converging, this is first unlikely to get past the testing of the detonator itself (separate from the bomb), second would have been rapidly diagnosed and corrected, and third would not have stopped the bombing of Hiroshima.
 
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