If a nuclear missile was targeted at a nuclear reactor, would/could the reactor’s resident radioactive materials become involved in the chain reaction, massively increasing the power of such an explosion?

Question
Mudassir Ali 9 months 1 Answer 132 views

Answer ( 1 )

  1. No, a nuclear reactor would not enhance the explosion of a nuclear bomb except to add a lot of fallout.

    The reason is that nuclear fuel in a nuclear warhead is incredibly enriched uranium-235 (90%+ enrichment) and/or weapons-grade plutonium-239 (with as little plutonium-240 as possible). The nuclear “pit” of the fission primary has almost nothing but that pure fuel configured to be imploded to greatly increased density (over 400%). When you consider that Earth’s core has the density of its material increased about 25–50% by the entire weight of Earth, then you’ll note that a nuclear weapon’s stunt of achieving 400% compression is rather epic.

    Further, it is at the moment of implosion that a nuclear weapon throws a lot of neutron-making efforts at the core. Little neutron generators spew streams of neutrons into the core. Tritium gas is injected into the hollow core. And so on.

    Nuclear weapons also include features like tampers (to slow the core’s initial explosion, giving neutrons more time to split fuel) and neutron reflectors (to give escaping neutrons a second chance to go back and split some fuel.)

    Meanwhile, the nuclear fuel in nuclear reactors is typically about 3–5% enriched uranium. But it’s not pure metallic uranium. It’s uranium oxide, usually, so every two out of three atoms in a fuel pellet are oxygen, not uranium. Further, the uranium oxide pellets are usually filled with fission waste like cesium that is not fissile, or actively absorbs neutrons (like xenon-135). Further, the pellets sit in stainless steel tubes (for corrosion protection) with some sodium (for heat transfer). Further, the stainless steel fuel assemblies are in spaced bundles designed to allow water to flow around, carrying away heat. At that point, less than 1 in 1,000 atoms in a given volume of a reactor is a fissile uranium-235 atom.

    Compare that to a nuclear weapon, which compresses very rich nuclear fuels into a densified lump.

    But in a further difference from nuclear weapons, most nuclear reactors add key features that absolutely squelch and cripple nuclear explosions: moderators and control rods. While both the USSR and US experimented with moderated nuclear weapons, they failed utterly. (The US’s “Ruth” test failed to destroy the tower it was mounted on.)

    Adding in neutron-absorbing control rods and the reactor’s heavy radiation shielding means the atom-splitting fast neutrons from a nuclear weapon aren’t going to stimulate any nuclear explosion out of the diffuse, low-enrichment fuel in a reactor.

    A nuclear weapon could, however, utterly scatter the contents of a reactor in the ultimate “dirty bomb.”

Leave an answer