Why can't a nuclear reactor cause a thermonuclear explosion.?

Answer 1

okay. well, in a nuclear reactor, uranium or plutonium is bombarded with neutrons in order to force it to split and release huge amounts of energy. elements with 92 protons and up will nearly always absorb a neutron and split without hesitating.

in a nuclear reactor, the uranium is highly enriched, which means it contains certain uranium isotopes that are less stable than others, therefore making it easier to split (and it IS weapon grade). it is kept at what's called the critical mass level. subcritcal mass wont sustain a chain reaction, and supercritical mass will cause a runaway chain reaction, like in an atomic bomb. the control rods in the reactor can be pushed in and out of the core, which contains the uranium (U) or plutonium (Pu). when the rods are all the way in, the reaction comes to a halt, when they are all the way out (they never are) the reaction reaches supercritical levels and escapes control. (this happened at chernobyl). there are other ways for a reactor to reach the supercritical level, the control rod material plays a part, the coolant, and of course those controlling the reaction. control rod material is very important, because if the material the rods are made of do not absorb enough neutrons, they will allow the reaction to continue (this happened at chernobyl, the material actually caused an increase in reaction speed and power). the coolant must have a very low void coefficient, (the void coefficient tells how much of the liquid is gas pockets at any given time. water has a high void coefficient) or else the gas pockets will allow extra heat to build up, therefore allowing the reaction to escape control, and possibly melt the core, as what happened at Three Mile Island.

in short, a nuclear reactor cannot cause a thermonuclear explosion, because all current nuclear reactors are fission reactors, and thermonukes are fusion. however, the fission reactors in operation CAN cause an explosion (and it IS a nuclear explosion. nuclear particles and waste material are ejected from the reactor when it explodes. this can cause acute radiation poisoning in surrounding area), if they are not very carefully, precisely, and intelligently monitored.

Answer 2

First of all, a thermonuclear explosion is one that uses fusion, not just fission. A nuclear reactor uses fission. The main reason that a reactor can't cause a nuclear explosion is that the fuel is not as pure as that in a bomb and there are also controlling rods which slow the neutrons. It is possible for the reactor core to heat up enough to melt and that can cause chemical explosions if the water around it decomposes, but the run-away reaction needed for a nuclear explosion can't happen.

Answer 3

It comes down to purity. The fuel in the reactor is about 5% pure. What causes the runaway reaction that is a nuclear explosion is a series of collisions by neutrons with atomic nuclei. Say a neutron hits a Nuclei, it splits it and releases ten more, because refined plutonium is very dense and pure then two of the neutrons then hit nuclei which then produce twenty neutrons which spit four more atoms which release forty and so on.

This cascade depends on neutrons hitting the right kind of nuclei, if the material is say 98% pure then it is much more likely to cause a chain reaction, if it is less pure more neutrons are caught by stable atoms that just change into isotopes by absorbing the neutrons. However this process creates heat which is the source of power for Nuclear Reactors.

If that heat becomes too great it simply melts the reactor, making it useless but not making it explode because again it never reaches the purity needed for an explosion.

What creates the danger of explosion for a reactor is the water used to cool it stops flowing it can be sublimated into hydrogen and oxygen gas which will explode and of course increase in steam pressure.

Answer 4

In order for there to be a thermonuclear explosion...either fission or fusion has to occur. preferable with high grade plutonium. In a nuclear power plant there are no means for this to happen. The worst case scenario in a nuclear power plant is a "china syndrome" or melting of the radio active rods with a massive release of radioactive material or "cloud".

Answer 5

Solar flares don't really have any effect on small things (like a building). You need to get very long things (like miles of power lines) to get induced currents that can damage equipment. So you could knock out the power lines around the power plant, but the flare wouldn't affect the plant itself. An EMP would be more serious. Unless the electronics in the plant were specifically hardened, they could be damaged or destroyed. Any reactor would have multiple backup methods for shutdown that could be used manually. So an EMP could take the power plant offline and prevent it from producing useful power, but it shouldn't cause any type of failure of the fuel itself.

Answer 6

actually it does cause them, a lot of small controled ones

Answer 7

The premise of your question is not correct.