Nuclear decommissioning is an expensive business. It is estimated that the decommissioning of existing sites in the UK will cost in the region of 70 billion GBP, but this is not taking the timescale of such operations into account. As the process happens in stages, the true cost is hard to determine.

In the UK the Nuclear Decommissioning Authority (NDA) is the body responsible for sourcing contractors to carry out nuclear site cleanup. It aims to provide cost effective decommissioning of existing sites and implementation of long term management of sites while they are being dismantled. It is not just power plants that require decommissioning; although concern about the safety of such nuclear establishments are at the forefront of public concern, there are also a number of other industries that require the same treatment when it comes to shutting down.

Particle accelerators, such as the much publicised Large Hadron Collider (LHC), uranium mines and isotope production plants all require the services of a safe decommissioning contractor. The official stance on the process is to return the buildings and the site itself to a safe and decontaminated state so that it can be dismantled or reused with no risk of nuclear contamination.

Due to the increase in demand for energy, the mid 1900s saw the introduction of nuclear power facilities; and it is these facilities that are coming to the end of a lifetime of service. The need for economic and safe treatment of such plants has reached a crescendo as the new generation of reactors are ready to take their place. There could be as many as 10 new-style reactors required to meet the energy needs in the UK and although the new designs mean that less fuel will be used and will last longer, there is a chance that existing decommissioning and waste storage techniques will not be adequate.

The crux lies in the fact that the new rods have a higher burn-up rate, which in turn creates a much more radioactive substance when it comes to disposal. The increased radioactivity of the uranium generates more heat, which becomes a problem during storage after use in a reactor. Being able to consider a flexible approach to the storage of nuclear waste requires an open minded appreciation of the route the development of nuclear power facilities could take. Keeping the estimated and real costs of decommissioning down becomes more difficult if the fuel is more radioactive. In addition, if more repositories are required to enable the safe storage of super heated rods, the costs are going to increase in the reclamation of sites post-nuclear use.

According to NDA, the radioactivity of the new type of uranium rod from the proposed reactors will be twice the level of our existing radioactive waste today. Although the disposal of the waste and the decommissioning of the sites will not be carried out until 2080, leaving the problem for the next 70 years is not an option. Far too often the industry is accused of leaving the safe handling of nuclear waste, fuel and facilities for future generations to work out, and at a time when we are currently paying a high price for safe nuclear decommissioning, we should appreciate the implications this may have on the future decommissioning contractors.

In one of this most important publications , Einstein has described the process of stimulated emission of radiation. This means that a photon hitting some atom may not only supply energy to this atom in an absorption process, but also send an already excited atom back to a state with lower energy. In the lattter case, an additional photon is emitted. A crucial aspect is Einstein’s insight that the additional photon should move in the same direction as the incoming photon. We thus have a process of light amplification: we get two photons out of one, or transform some light beam into a more energetic one. Furthermore, Einstein has realized that a net gain of optical power in some ensemble of atoms can occur only if there is a so-called population inversion: the upper energy level must be more strongly populated than the lower one, so that the effect of stimulated emission can exceed the one by absorption of atoms in the lower state. This state is often achieved by “optical pumping” e.g. of a laser crystal – an invention attributed to Alfred Kastler.

For a laser, one more thing is required: a “resonator”, in which a light beam can circulate, and an amplifying medium can at least compensate for the power losses in each round trip. This principle was first demonstrated with microwaves, and by the ground-breaking work of Schawlow, Townes and Maiman around 1960 it could also be applied to light.

As the work between 1917 and 1960 has certainly brought more than only the clarification of some minor details, it would be rather far-fetched to call Einstein the inventor of the laser. However, he has indeed realized the most important physical basis of the laser – the process of stimulated emission. This, by the way, was done not by observing physical phenomena, but via theoretical reasoning. After that, there was still a far way to the laser.

there is a similarity to the story of the nuclear bomb. According to the equation E=mc2, a huge amount of energy should be released when just a few grams of matter are converted to energy. Without doubt, this is a very important finding. Nevertheless, it is still another thing to identify a way to do this conversion. Such a way was found via the discovery of nuclear fission by the team of Lise Meitner, Otto Hahn and Fritz Strassmann in 1938, and the realization of the possibility of a nuclear chain reaction soon after. In this sense, Einstein is related to the atomic bomb perhaps more via his famous letter to president Roosevelt than by the mentioned equation. And Max Planck could present an equation , but no letter, and is not considered to be the father of the laser, but at most a father of the photon, which was later named so by Gilbert N. Lewis.