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

核裂变是当今最有效的能源生产方法之一。它提供了一种几乎无碳、强大和稳定的能源，能够产生基本负荷电力，目前的研究正在改善这种能源的安全性、废物管理和完整性。核燃料循环所有方面的基础是对整个过程中涉及的许多过程的物理规律的理解。许多这些物理过程需要精确的核数据，即物理数字来模拟和预测基本尺度上非常高水平的工作。核数据领域的研究目标是提供能够尽可能准确地描述这些核过程的数据。中子截面描述了中子与特定核素的相互作用概率，作为入射中子能量的函数，在许多核数据应用中使用。这些复杂的相互作用是无法预测的，因此必须通过实验找到准确的截面。通常，使用飞行时间技术，使用具有广泛能量范围的中子源来执行横截面测量，其中中子的能量由它沿着设定的飞行路径行进所需的时间决定。这项研究将主要以欧洲核子研究中心的中子飞行时间设施（n_TOF）为基础，在那里将进行高精度的截面测量，使核数据用户（核工业）能够更准确地模拟和了解整个燃料循环的许多过程。这项研究的一个方面是精确测量C-13的辐射捕获截面，C-13是天然碳的1.1%的同位素。C-13(n, γ)C-14的生产速率鲜为人知，但它决定了辐照石墨中放射性C-14的数量，英国约有96,000公吨。新的检测技术、样品可用性和实验设施将使这一数量的测量达到比以前更高的精度，有助于未来的废物处理和英国石墨慢化反应堆的退役。这项研究还将有助于n_TOF设施的外来裂变碎片光谱仪（STEFF）的计划测量，STEFF将测量核裂变过程中发射的伽马射线的能量和多样性。这些伽马射线是核反应堆产生大量热量（10%）的原因，目前可获得的数据质量相对较低。STEFF将利用n_TOF新的第二个实验区，在那里它将被放置在一个相对高通量的中子束中。这将允许将中子裂变过程的许多方面作为中子能量的函数来研究，特别是在高（MeV）中子能量下。最后，该研究将允许通过与工业界和英国核科学论坛（UKNSF）合作，解决英国在核数据领域的具体要求。

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).