From a little bang to a huge blockbuster is not that difficult
The Age, 12 0ctober, 2006
The spread of nuclear power makes weapons proliferation easier, writes Alan Roberts.
WHEN North Korea exploded its nuclear bomb on Monday, seismographs throughout the world registered the way the earth shook. In a different way, it came as a shock to most of us.
Unhappily, North Korea may be only the first in a long series of recruits to the “Nuclear Weapons Club”. Why? Two reasons:
First: more people are starting to see as the greatest threat facing humanity the way we are changing Earth’s climate — the “global warming” due to the billions of tonnes of carbon dioxide with which we go on polluting the atmosphere. And in appreciating this threat, they are, I believe, quite right.
Second: some of these people look to nuclear power as a solution, at least partially, to the frightening prospect of a world damaged beyond recovery. This view is not confined to nuclear industry spokesmen and some politicians, who have their own reasons for pushing nuclear power. It is shared by well-intentioned people who believe nuclear power can make a major and usefulc ontribution to averting this catastrophe.
Everyone knows about the tremendous store of energy locked up in the nucleus of an atom. At least on first glance, there is something very attractive about the prospect of letting it trickle out in a controlled and useful way. At the opposite extreme is the case in which all that contained energy is released suddenly in one gigantic burst: the nuclear bomb.
An obvious and unavoidable question is: given a reactor designed and operated to keep the energy coming out in a trickle, how easy is it to reshape it into the “burst” mode, to make a bomb?
There has been a lot of argument on this question over the years. The plutonium produced in reactors is certainly the material used in bombs. But, it can be said, maybe so, but it’s mixed with a lot of other stuff that lowers its explosive power. To which others retort, yes, but you can run the reactor in away that gives less of that unwanted stuff and so on. What is the truth?
Prominent people are now urging the revival of nuclear power after its many decades of stagnation, a revival that could see reactors operating in countries that never knew them before. So this question is pretty important: given a reactor, how easy is it to make a bomb?
Perhaps the most authoritative answer has been given by Victor Gilinsky, in his chapter on the topic in a book published on the internet in June, Taming the Next Set of Strategic Weapons Threats. Gilinsky was reappointed under three US presidents to serve on the Nuclear Regulatory Commission.
He treats in considerable detail the ways of getting a bomb from the fuel used in the most common reactor type, the light water reactor. His conclusions are summed up in his final sub-heading: “Light water reactors are less proliferation-resistant than usually assumed in policy discussions and are dangerous in the wrong hands.”
This moderate statement hardly does justice to the detailed case he presents. He gives references, for instance, to documents describing how to build a “quick-and-dirty” plant for extracting the plutonium from used fuel elements. Time required: four to six months with an area required of about 39 metres long and much less wide. A production rate of about a bomb a day, meaning “dozens of bombs before the IAEA (International Atomic EnergyAgency) could count on detecting it”.
He includes a table giving the likely explosive yields, in TNT equivalents,of bombs made in this way. To grasp it, we should recall the 10-tonne bombs used in WWII, known as blockbusters for their power to destroy a whole city block. If the early reports of the size of the North Korea test explosion are true, it amounted to “only” about 100 blockbusters or a bit less. He indicates that, with better technique, or more luck, it could have got into the range of 600 to 4,000 blockbusters.
The advocates of nuclear power on climatic grounds may be right or wrong. (I happen to be strongly of the view that they are wrong.) But in any case, they need to reckon with Gilinsky’s analysis, showing that any country with the(common) light water reactor is only a few months from having atomic bombs if it wants them. Are we entering a future in which disputes will not uncommonly reach the nuclear level, and threaten death to whole cities?
Alan Roberts is a physicist and former member of the nuclear safety committee of the Australian Radiation Protection and Nuclear Safety Agency.