How the neutron bomb works

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LAST Thursday in London, the skies went black at noon and the heavens opened.

At this point, I realised with a sense of shock that it was Hiroshima day, the 36th anniversary of the first use of an atomic bomb against an unsuspecting and unprotected civilian population.

If I had been superstitious or religious instead of scientific socialist. might have read an omen into those amazing thunderstorms. Anyway, this week's column is about nuclear war (information from the Guardian, New Scientist, and Science for People .

President Raygun. is busily upping the stakes in the nuclear war game, firstly with his decision to produce and stockpile the 'enhanced radiation weapon' (ERW) or neutron bomb. which can only result in the Russian bureaucrats following suit, and secondly with his decision to use spent nuclear fuel from commercial nuclear reactors as a source of weapons-grade plutonium, using top-secret laser isotope separation technology to remove Inev to remove unwanted contaminants.

The US government thinks this is necessary, as several reactors which usually produce plutonium for bombs have been closed down recently, while 'demand' for bombs is rising.

The particularly nasty thing about the ERW is that it is supposed to select.ively kill people without damaging property thence its nickname, 'the capitalist bomb' They are also supposed to be usable in 'theatre wars (where the war is contined to a relatively small area, rather than the whole world. The relatively small area designated by the Americans at present is Europe!.

How is all this supposed to be achieved?

The typical A-bomb, which works through the breakdown or fission of uranium or plutonium, releases its energy as blast 150%c), heat (35%), fallout (10%), and immediate radiation neutrons and gamma rays: 5%).

A pure fusion bomb (where two types of hydrogen are joined together to make helium in the same way as the s energy) would produce its energy mainly as immediate radiation (80%), with only 20% as blast and heat, and little as fall-out.

All existing fusion bombs (H-bombs) have a smalier fission bomb as a trigger, and this makes them more 'dirty' than a pure fusion bomb. The ERW is 'cleaner than most, but would release only 30-40% of its energy as immediate radiation. The rest would be blast. heat, and fallout.

So it's far from being the 'clean' weapon that is sometimes claimed.

It is also intended to be a smaller sort of bomb than the usual ones found in the military stockpiles. This is supposed to be so that it can be used to knock out the enemy's troops while avoiding damage to civilians who are quite a way from the field of battle HEMI (but if the field of battle is all Europe, that's not very reassuring!)

To this end, a typical ERW has an explosive yield of 1000 tons of TNT (1 kiloton), while the Hiroshima and Nagasaki bombs had yields of about 13,000 tons of TNT.

Of this yield, about -350 tons would be given out as radiation (fast, penetrating neutrons) while the other 650 tons worth would be heat and blast. This is equivalent to about 30 blockbusters (the largest conventional bombs used in World War 2).

But the ERW would not do what is claimed even if it produced all its energy as