Wednesday, 19 September 2012


I’m going to get a bit in depth this week and take a look at the effects of nuclear weapons. What does it say about us as a species that we created, or even conceived, such things?

More to the point, what would it actually be like to experience a nuclear attack? This a question that tickles the human interest in the macabre. On detonation, a nuclear weapon produces what is known as a “thermal pulse”, a wall of heat that travels out from ground zero at the speed of light, instantly setting fire to any flammable material within line of sight. Houses, trees, grass, rubbish in bins and human beings would burst into flames. Jonathan Schell, in his fascinating book “the Fate of the Earth”, cites that after the detonation of a twenty megaton weapon (with the equivalent power of 20 million tons of TNT) “people caught in the open twenty three miles from ground zero would be burnt to death”. In concentric circles further away from the point of detonation, people would receive burns that would later prove fatal, and many miles further out would be blinded if they happened to be looking in the wrong direction.

After the thermal pulse comes the blast wave. This is the air displaced by the energy of the detonation, pushed away at hundreds of miles an hour, much faster than a hurricane. Buildings made of anything less substantial than re-enforced concrete don’t stand a chance. Anyone who managed to evade the thermal pulse in the open would be picked up and bodily hurled with lethal force. Those who had taken shelter indoors would either be crushed as their houses crumpled like paper cups, or in more sturdy structures be eviscerated as windows erupted into razor sharp fragments. Cars, buses and train carriages would fly hundreds of metres. Although the blast would extinguish the initial fires started by the thermal pulse, others would reignite in its wake as ruptured gas mains spilled out into every street and petrol tanks under garages burst open.

Next is the firestorm. When enough material within a certain area is on fire, the volume of inrushing air feeding the fire becomes so great that it enters a positive feedback cycle, only putting itself out when all flammable matter has been exhausted. Those who had survived the thermal pulse and blast wave would have to escape quickly or be sucked into the firestorm, as again winds reached hundreds of miles an hour, but this time in the opposite direction.

Finally comes the fallout. Fallout is any material, generally buildings and earth, which is vapourized and sucked up by the initial explosion and thus made extremely radioactive. It then falls back to earth with the prevailing winds and can render wherever it lands uninhabitable for weeks, hence the need for “fallout shelters”. So, anyone who had somehow survived the previous three effects and sought refuge downwind of the blast would be subjected to potentially lethal radiation. It must also be remembered that even if the area you are in did not receive a direct hit, depending on the winds fallout can travel many hundreds of miles, so that in a large scale attack there would be very few places unaffected. Thus there can be no outside help, because every city is just as burnt, blasted and irradiated as any other.

There are many, many less immediate effects of nuclear weapons, the most important of which are the social effects. All the comforts of modern life would evaporate. There would be no electricity, no gas, no running water, no working toilets, no rubbish collection, no petrol left in the pumps. There was mass panic buying in the UK recently at the threat of petrol shortages. Imagine the scenario of millions of terrified, hungry people trying to take to roads to find some modicum of safety. Petrol would become worth its weight in gold, and people would easily kill for it.

Food supplies would be drastically cut, as modern farming depends on petrol driven machinery and artificial fertilizers. Regaining even a subsistence level of farming would be difficult, as traditional non-mechanised methods have essentially been forgotten. What few doctors survived the attack would find their hospitals in ruins, their supplies buried in the rubble, each one overwhelmed by hundreds of horrendously wounded patients. It’s very unlikely that any new supplies would reach them. They would soon find themselves trying to treat people without clean bandages, antibiotics or drugs. Not only this, but millions of human and animal corpses would lie rotting in the streets and fields, spreading disease amongst a catastrophically weakened population.

Whilst all of this was going on, the ecosystem itself would very probably be dying, as what trees and plants weren’t irradiated would be denied sunlight by the billions of tons of smoke and soot filling the atmosphere. Day would become twilight, and ash from millions of incinerated trees would settle on everything like snow. Respiratory ailments could become endemic for years afterwards. So, as Schell points out, both manmade and natural systems would breakdown irrevocably.

As President Jimmy Carter put it in his farewell speech, “the survivors, if any, would live in despair amid the poisoned ruins of a civilization that had committed suicide”. Not only might we kill civilization, but our race and our planet as well. Pretty bleak stuff really, isn’t it?

Tuesday, 11 September 2012

Space probes, light houses and pacemakers

Bit of a lengthy post this week folks, but bare with me, it’s going somewhere…

You might think of nuclear energy as being used in only two ways; in a nuclear reactor in a power plant helping you boil the kettle, or in the core of a nuclear weapon. However, it turns out nuclear energy can be used, and produced, in some more unusual ways.

Not only do radioactive isotopes constantly give off radiation at a known, steady rate, but they also give off heat, sometimes for many years. Some of them are warm to the touch, and plutonium 238 will actually begin to glow red hot if you cover it with an insulating material (as seen in the picture above). This property is exploited in devices known as radioisotope thermoelectric generators (or RTG’s), which convert this heat into electricity for powering systems that must function for long periods of time without maintenance, such as space probes.

As with many other areas of nuclear history however, the deeper you look, the more peculiar it becomes. It turns out that plutonium batteries were used, in a very limited number of cases, to power pace makers. Its pretty hard to think of an element more hostile to life than plutonium; massively radioactive and poisonous, and a key component of most nuclear weapons, yet here it is playing a role in preserving life.

RTG’s were utilised for one more unlikely task; powering lighthouses in remote regions of the Soviet Union. It was a bit much to ask someone to man a conventional lighthouse on the vast, icy wastes of the north Russian coast, so they were instead fitted with RTG’s that would require no maintenance over their lifetime.

This though gives rise to a very frightening possibility. Because the RTG’s are in such remote locations, someone could nick a cheeky bit of radioactive material and nobody may ever notice. What’s the big deal you say? Surely no one can make a nuclear bomb out of that? Well, not strictly speaking, but they could make a crude, so-called “dirty bomb”. This is a conventional explosive strapped onto a quantity of a radioactive isotope, which spreads it over a given area and renders it uninhabitable. Imagine what would happen to the UK economy if one of those went off in the city of London’s “square mile”…

Indeed, the whole of nuclear history is fraught with fears of weapons or nuclear materials going missing. The fact remains that it’s actually pretty easy to mislay a nuclear weapon. The US alone has 5113 of the things, so they’re bound to drop one behind the sofa occasionally. It is believed that they have lost eleven, often in tragically comic circumstances, such as when a jet armed with a 1 megaton bomb rolled off the deck of an aircraft carrier in 1965, immediately sinking to the bottom of the ocean and taking its pilot and its lethal cargo with it.

Perhaps even more sinister than the possibility of these weapons getting into the wrong hands is the possibility of computer error in missile warning systems. The most chilling example is the so called “Norwegian rocket incident’ of 1995. American scientists had informed the international community they would be launching a research rocket that would follow a trajectory similar to that used by nuclear missiles, but apparently not all parts of the Russian military had been told. The appearance of the rocket on radar screens caused a mass panic, and the briefcase containing Nuclear launch codes was presented to then president Boris Yeltsin, who had seconds to make a decision. Blind luck prevailed as Yeltsin decided not to launch. I leave you with the cheerful thought that this situation could recur at any time, and not end quite so well…