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

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).

This fellowship will have a far reaching impact both nationally and internationally. The main beneficiaries of this research will be industry, academia, future generations and the wider public.

Industry: The nuclear industry comprises of the largest user of nuclear data and thus new data sets originating from this research will be used throughout the nuclear industry internationally. Industrial users of nuclear data will have access to the data sets resulting from this fellowship through the evaluated libraries such as JEFF within the NEA data bank but also directly through the pathways between the University of Manchester and industries already in place. The research will have impact on on-going projects such as the decommissioning and waste disposal of the AGR and Magnox reactors and future projects such as advanced reactors (Generation IV) and Accelerator Driven Systems. The nuclear industry will benefit as a whole from this research however specific companies such as the National Nuclear Laboratory will benefit from for example work performed on 241-Am. Industry will benefit from strengthened ties with academia which will further research into not just the field of nuclear data but also other topics that are of shared interest to academia and industry.

Academia: This research will impact the academic community in a variety of ways. Firstly, many of the proposed experiments use novel techniques in the field of cross section measurements, such as the 13-C capture cross section measurement. The possible experimental setups will impact upon many other areas of academia where scintillators are used to detect radiation from a sample in high background areas. Further experimental techniques developed at the n_TOF facility such as the use of a calorimeter to detect capture cascades and a MicroMegas detector to detect fission fragments are of interest to the other academic groups within the UK studying nuclear reactions, such as those at the University of York and the University of Surrey. The data to be taken with the Spectrometer for Exotic Fission Fragments (STEFF) offers insight into the spin de-excitation process of fission fragments, impacting upon theoretical work in the field of nuclear fission.

Future generations: This fellowship aims to recruit a PhD student from another scheme, such as a Centre for Doctoral Training who will be trained to be an expert in the field of nuclear data measurements. The UK has very little expertise remaining in this field, and any knowledge transfer is extremely important and the many different aspects of this research will allow a new student to gain knowledge on a wide variety of crucial topics. This drive has been endorsed by the Nuclear Innovation and Research Advisory Board (NIRAB) to re-establish nuclear experts in the UK. This fellowship will also have impact on a wider pool of future scientists who are interested in research benefiting the nuclear energy industry. The four PhD students currently working on the n_TOF facility within the applied nuclear physics group at the University of Manchester will be supported through this fellowship.

Wider public: Nuclear fission is a field which can have a huge impact on the wider public, as it is an area that can often divide opinion. All ages, genders and social communities will be impacted through this fellowship through outreach events. Finally, this research will lead to the continuation of clean, carbon free energy production from nuclear fission with an even higher knowledge of the nuclear data driving the fundamental processes involved in this field. This has a global impact as carbon free energy sources become increasingly important.