One of the greatest challenges facing the U.K. nuclear industry is the disposal of nuclear waste. Many tons of spent nuclear fuel is piling up at reactor sites and will have to be stored onsite because there are no national geological repository. Some spent fuel is reprocesses to recover fissionable materials to make new fuel but that only accounts for a small part of the total waste. In addition, components of the nuclear reactors are contaminated with radioactivity that will make decommissioning and disposal difficult. Nuclear weapons manufacture generates its own type of radioactive waste.
While various solutions to the disposal of spent nuclear fuel, nuclear weapons waste and old reactor components are being discussed, research continues at U.K. universities and laboratories on the exact nature of different types of nuclear contamination in the hope that a better understanding of such contamination will aid in the decommissioning of shuttered nuclear power plants.
Scientists at the Dalton Nuclear Institute of the University of Manchester, the National Nuclear Laboratory and Diamond Light Source, the synchrotron science facility for the U.K., have just finished a research project on irradiated materials to further understanding of how to improve future decommissioning projects for the U.K. reactors that will have to be closed down in the near future.
A cylinder of concrete referred to as a "core" was removed from a nuclear fuel cooling pond at the closed Hunterston A, Magnox nuclear power station at Ayrshire. The core was coated with multiple layers of paint. It was contaminated with strontium and cesium from sixty years of operation of the reactor. The core was brought to Diamond Light for examination and testing.
It was discovered that the strontium which is a highly radioactive fission product was chemically bonded with the titanium oxide in the white paint that coated the core. The cesium, on the other hand, was bound to the clays and iron oxides that made up part of the rock fragments in the concrete. This discovery was a valuable finding because knowing exactly where the radioactive materials were located in the core will make future research easier and may ultimately save millions of dollars in decommissioning costs.
It was also found that the layers of paint and rubberized coating materials had successfully functioned as a sealant and remained intact despite being in the reactor for sixty years. Even if the contaminated water from the cooling pond had penetrated the coating on the core, the strontium and the cesium were unlikely to be leached out of the concrete.
The head of the Dalton Nuclear Institute said, "This work shows the power of the techniques available at the Diamond synchrotron to meet the challenge of cleaning up our nuclear legacy and the University is working very closely with Diamond to develop facilities to support research across the whole of the nuclear industry".
The Chief Technologist for Waste Management and Decommissioning at the National Nuclear Laboratory remarked, "This research project has demonstrated that collaboration with academia, industry and Diamond scientists, utilizing the national scientific infrastructure delivers high-quality research with industrial relevance and impact."
The CEO of Diamond Light Source said, "Diamond is very pleased to have facilitated this decommissioning-related research and one major component of our future development plans is to help the UK address the complex and varied challenges of the nuclear industry."
