Flights grounded in Pittsburgh after two small planes violate airspace near nuclear power plant

KDKA radio Pittsburgh | 10/31/01

[El Gato]

Correct. Both were designed to withstand the direct impact of a 747.

Isn't that what they said about the WTC, too

Not quite. It was designed to survive the impact of a 707 class aircraft. Both towers survived the impact of the larger 767 aircraft. What they did not survive, was the fire caused by all that jet fuel. That weakened the steel structure to the point where it buckled. Then the weight of the floors above the buckle point came crashing down on the floor below, causing it to fail and fall onto the one below it, and so forth. A containment vessel doesn't have floors and the steel is inside the concrete. Be kind of hard on the building(s) outside the containment structure, but the reactor would be fine. I have a feeling that the video of the WTC towers pancaking will be shown to generations of engineering students, just as the film of the first Tacoma Narrows bridge ripping itself up has been shown to several generations of them since that event in 1940, as an object lesson in being very careful about ones design and analysis assumptions.

[Snerdley]

It probably would add to the ammount of radioactive fallout, but I suspect the quantity of material in a reactor wouldn't add more than a few percent more.

There really isn't any way whatsoever that it would result in a greater yield. For that to happen, they'd have to get the first stage to compress all the reactor fule to a critical mass before it's totally vaporized. That's the problem. Nuclear bombs aren't really explosions like dynamite, they are huge Heat Bomb. They release a tremendus amount of energy in heat, vaporizing everything inside a certain radius. The expanding mass of vapor and heat generates a shock wave, which can blast down buildings and such, but it won't compress any mass to a central point. In our bombs, this happens in the core of the bomb, with all the explosive power directed inward on the nuclear fuel, creating a critical mass that starts the reaction above.

Also, the fule in our reactors are pellets or rod shaped. The fuel in a bomb is spherical. How do you just happen to get all the explosive forces just right to compress a rod into such a critical mass? Especially if you have to blow down 10 foot thick re-enforced concrete containment walls.

Basicaly, you can't make a bigger bomb by hitting a Nuke plant. You may get a little more fallout, but probably not as much as how the detonation is done (Airburst vs. Surface vs. Underground). The psyological impact of a nuclear plant disaster (if a nuclear bomb wasn't enough?!?) might be one of thier goals though. And the disruption of power production (probably pretty minimal unless you take out a bunch of plants).

-Snerdley

"Never start a fight, but by God, ALWAYS FINISH IT!"
-Captn John Sheridan
Earth Space Station Babylon 5

[chimera]

The explosion would breach the containment wall and reactor and vaporize most of the reactor core.

The studies I have seen indicate such would occur with a warhead in the 0.1 MT and above range if it were placed in contact with the containment. In the 10 to 100 KT range you'd probably have a breech with some damage to internals, but no vaporization of the pressure vessel. In the 1 to 10 KT range, probably cracking of the containment walls but little or no internal damage. Below about 1 KT, you'd have some spalling of the concrete and cosmetic damage, but no large-scale cracking or breach.

Would this additional material that is fissionable and in a tremendous quantity add to the energy released? If it was to far away and less densly packed than a warhead to add energy than would all this material be thrown up into the atmostsphere and add to the horrendous amount of radioactive fallout. Fusion bombs are two and three stage tritium, but densely packed around the core of the fission central core. What happens when a nuke goes off near a large commerciol reactor with 20 tons of fissionable uranium in its core?

You seem to be alluding to some kind of boosted yield weapon design and the possibility of a reactor core acting in such a way. While fast fissions in U-238 add to the total weapon yield, a major effect they have in a staged device is adding to the neutron total to enhance the production of tritium from the lithium deuteride matrix, as well as increasing the fission reaction rate in the plutonium. The system is carefully designed to achieve this through placement of the materials and direction of the radiation. An outward-travelling explosive wave would likely just disrupt the uranium assembly, not compress it or otherwise cause it to behave in the way the components of a weapon do.

As far as adding to fallout inventory, it would probably be more than if the weapon were denotaed in isolation, but remember, fallout production yields from weapons effects are measured in the gigacurie range, while the activity inventory in fuel assemblies with high burnup and freshly "burned" are in the megacurie range. So the added amounts would be on the order of tens of percent. Not insignificant, but also hard to call a "horrendous" increase.

[chimera]

Sheesh I always hate when these threads turn into flame threads over semantics.

Oh well anyway, Beaver Valley 1&2 will always be known to me as the Shippingport nuclear power plant and probably also to 90% of the people who live in the Pittsburgh metro area.

I guess that is the cost of living in the "boonies".

Fair enough. I'll have to keep that in mind. No flames intended, believe me. Just an attempt to explain the basis of my misunderstanding. To the extent that I shot from the hip and misunderstood the meaning of the initial post, I will take the blame for that.

[Chuck_101]

You are on the right track with your explanation.

Virtually every small plane today is equipped with a mode C transponder, and they are set on one frequency for normal flight....1200...the key is, that to an air traffic controller, each transponder looks the same on their screens...so in order to eliminate clutter, and enable ATC to spot a potential intruder, general aviation must stay outside the TFR (temporary flight restriction) zone through November 7.

A humble private pilot, at your service.