PROLIFERATION TO IRAQ

In March, a sting operation led to the apprehension of an Iraqi gang, including diplomats in Britain, who were smuggling com-ponents for triggering nuclear bombs from the US to Iraq. The components were said to be krytrons, which seems unlikely; con-ceivably, and I am only guessing here, this story was put out by Western intelligence services to mask their knowledge of more advanced Iraqi projects.

The trigger for a nuclear bomb is made of plutonium, which (like U 235) explodes when sufficient neutrons from one atom hit other atoms to liberate more neutrons and keep the chain reaction going. In a small piece of the metal this cannot happen because most neutrons escape harmlessly through the surface, and a sphere with a sufficiently great volume-to surface ratio (i.e., with a critical mass) must be formed from subcritical components almost instantly and with sufficient force to hold them together against the force of the nuclear explosion until all of the fuel is consumed. Otherwise the explosion will fizzle or not set in at all.

The most primitive way of achieving this, last used in 1945, is to implode many subcritical masses of plutonium, each exactly timed and with its own chemical explosive, into a central sphere. Activa-tion is achieved by a device called krytron, essentially an electronic switch, but its glass envelope filled with radioactive krypton to pro-vide the initial neutrons starting the chain reaction.

If that is what the Iraqis hope to use, it is comparatively good news, because the mechanism is bulky, heavy, unreliable, and generally 45 years behind the times. At least two more modern ways are public knowledge now. One guides and times the shock waves of the initial (chemical) explosion round the circumference and through the plutonium trigger in a way that assures simul-taneity; the other has the plutonium trigger assembled as a ring surrounded by a layer of lithium deuteride, a layer of explosive, and a plastic container with sufficient inertia to contain the begin-ning of the explosion. The plutonium parts are compressed and the chain reaction is started by the neutrons from the lithium.

These modern triggers require no high-tech electronic com-ponents, which makes the krytron story a little quaint, though there can be no doubt that the Iraqis have both the capability to make nuclear bombs and the will to use them. This was clear in 1981, when the Osirak research reactor was ready to breed plutonium the way India did: by &st irradiation of U 238. At the time, the Israelis bombed it to bits in what to this day remains the only act of successful non-proliferation since nuclear bombs were invented.

This was followed by the entire world's heartrending whines about Israel's vicious aggression, notwithstanding the fact that Iraq was (and still is) legally at war with Israel. The International Atomic Energy Commission in Vienna, an excellent body for tech-nical information, but otherwise the same type of servant to tyran-nical regimes as the UNO of which it is a part, published a report by two observers whitewashing the reactor by implausible and ir-relevant arguments, without ever trying to explain what many (pos-sibly 200) tons of depleted uranium were doing on the reactor grounds (as pointed out in [AtE Aug 81]. Depleted uranium is the tailings of yellow cake (U 238 plus U 235) after enrichment; the enriched part has more of the fissionable U 235 and is used for power fuel, the tailing is depleted of it and has virtually no other uses than to breed it into more fuel or bombs. (The conservation-minded US has 200,000 tons of it in tanks at Oak Ridge doing nothing while the Earth Day rites on April 22 will call for stringent energy conservation measures.)