Nuclear power is developed in a society in the belief that it will provide a relatively cheap energy source and reduce dependency on external energy sources. This form of energy, however, presents grave risks not only from reactor accidents and the storage of waste products, but also from the release of radioactive material by terrorist sabotage or conventional warfare. Short of converting to a garrison state, societies cannot effectively protect the nuclear fuel cycle against sabotage; this is a problem which will only increase as nuclear reactors proliferate. The diversion of plutonium by terrorists for conversion to atomic or radiological weapons presents additional risks, since unidentified or unlocated terrorists cannot be deterred by threat of retaliation.
In any future war, electricity-generating power stations are likely to be primary targets of attack, because their destruction could paralyse the whole war effort of a country. The trend towards ever larger power stations, arising from economy of scale, makes each such station a highly attractive target. These installations will no doubt be strongly defended, but the greatly improved performance of modern missiles - in terms of (even non-nuclear) explosive power, range, payload and accuracy - ensures a high degree of success in such attacks. All this applies especially to nuclear power stations which contain reactors of very high output - sometimes two or more in one station - and which may provide a significant proportion of the energy needs of a country. Putting them out of action could have a devastating effect on the economy, particularly in countries which plan to obtain most of their electricity from nuclear reactors, quite apart from the huge material loss, since reactors represent a very large concentration of capital investment.
There may be another important reason for making a nuclear power station a primary target, namely the release into the biosphere of an immense quantity of radioactivity. Such a release, with the consequent contamination of a large area and the panic that this would cause among the population, might indeed be the main purpose of the attack.