Research on Nuclear Data measurements and evaluations for nuclear fission energy.

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Nuclear fission is one of the most effective energy production methods available today. It provides a virtually carbon free, powerful and steady energy source capable of producing base load electricity and current research is serving to improve the safety, waste management and completeness of this energy source. Underlying all aspects of the nuclear fuel cycle is an understanding of the physics governing the many processes involved throughout. Many of these physical processes require accurate nuclear data, that is physical numbers to model and predict to a very high level the workings on a fundamental scale. The goal of research in the field of nuclear data is to provide data which can describe these nuclear processes as accurately as possible.Neutron cross sections describe the interaction probability of a neutron with a specific nuclide as a function of the incoming neutron's energy and are used within many nuclear data applications. These complex interactions cannot be predicted and therefore accurate cross sections must be found through experiment. Commonly, a source of neutrons with a wide range of energies is used to perform cross section measurements using the time-of-flight technique, where the energy of the neutron is determined by the time it takes to travel down a set flight path. This research will be mostly based at the neutron time-of-flight facility, n_TOF, at CERN, where high precision cross section measurements will be performed, allowing the nuclear data users (the nuclear industry) to more accurately model and understand the many processes throughout the fuel cycle.One aspect of this research will be to accurately measure the radiative capture cross section of C-13, an isotope found in 1.1% of natural carbon. The C-13(n,gamma)C-14 production rate is poorly known, yet determines the amount of radioactive C-14 within irradiated graphite, of which the UK has approximately 96,000 metric tonnes. New detection techniques, sample availability and experimental facilities will allow this quantity to be measured to a higher level of accuracy than previously, aiding future waste disposal and decommissioning of the UK's graphite moderated reactor fleet.This research will also aid in planned measurements with the Spectrometer for Exotic Fission Fragments (STEFF) at the n_TOF facility, where STEFF will measure the energy and multiplicity of the gamma-rays emitted during the nuclear fission process. These gamma-rays are responsible for significant (10%) heat production in the nuclear reactor and currently the data available is of a relatively low quality. STEFF will utilise the new, second experimental area at n_TOF where it will be placed in a relatively high flux neutron beam. This shall allow many aspects of the neutron fission process to be investigated as a function of neutron energy, particularly at high (MeV) neutron energies. Finally, the research will allow specific UK requirements to be addressed in the field of nuclear data by collaborating with industry and the UK Nuclear Science Forum (UKNSF).