Modelling the electron anti-neutrino flux from nuclear reactors

模拟核反应堆的电子反中微子通量

• 批准号: 2435526
• 金额: --
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2435526
• 关键词: Modelling; electron; anti; neutrino; flux

Since the first experimental detection of the neutrino, with the Cowan-Reines experiment in the 1950s,nuclear test reactors have played a central role within the field of neutrino physics as a source of electronanti-neutrinos. These electron anti-neutrinos can be detected through an inverse beta decay reaction:[1] and arise from the beta decay of neutron rich nuclei formed by the fission of majoractinides within the core. As a result, this electron anti-neutrino flux is inherently tied to the operation ofa reactor, and related to the power of the reactor and the fissile inventory of its core [2].Given the dependence on the operational parameters and fissile inventory of a reactor, the concept of utilisingneutrinos to monitor reactors has existed for some time, but it is only recently that the understanding of thehas made such prospects feasible [3]. In contrast to current IAEA procedures, anti-neutrino based safeguardsallow for bulk accountancy of nuclear fuel, yielding an estimate of the masses of fissile material producedwithout necessitating assumptions regarding the mass of items. Additionally, anti-neutrino methods arenon-invasive, being carried out through use of a detector at a standoff distance from the reactor and allowfor real time measurement of the core.In the near future, the most reasonable expectation for the utilisation of this technology is through thedeployment of tonne-scale portable anti-neutrino detectors at a standoff distance of the order of 10 metres.At these distances, neutrino oscillation experiments have demonstrated the vastly reduced effects of neutrinodisappearance on the flux compared to detectors operating at far greater standoff distances, such as in theKamland experiment [4] [5]. Whilst far field monitoring of nuclear reactors through neutrino detection is adesirable prospect, the contributions of neutrino mixing and the increased background of the spectra greatlyincrease the complexity of modelling required.Use of the electron anti-neutrino spectra for the purposes of reactor monitoring is reliant on deviationsfrom an expected flux and energy spectra. Thus, models of an expected flux and energy spectra are neededin comparison with the measured rate, where through statistical methods, a threshold for a significant deviationfrom the model, and the time frame needed to detect this deviation, can be established [6].This anti-neutrino modelling is likely to form the main underpinning of a thesis in anti-neutrino physics.This will include generation of anti-neutrino source terms for reactors based on operational data providedfrom nuclear reactors, such as Hartlepool, along with spent fuel inventories. These source terms will bequantified to include to provide an estimation of the flux incident to a detector at varying distances, consid-1ering phenomena such the neutrino mixing of this flux along with the expected evolution of a nuclear core ona real time basis, something that existing applications, such as geo-neutrinos [7], do not consider and mighttherefore be used to inform such software.Beyond this, several avenues exist for further pursuit. These include phenomena such as the unexpectedexcess of anti-neutrinos detected at around 5 MeV with an unknown cause, speculated by some to be due topossibilities such as neutrino induced deuteron disintegration or coherent elastic neutrino-nucleus scattering[8]. Another, further, anomaly that may lend itself to investigation is that of the drop in expected reactoranti-neutrino events in short baseline experiments [9].2 References[1] Cowan, C., Reines, F., Harrison, F., Kruse, H. and McGuire, A., 1956. Detection of the Free Neutrino:a Confirmation. Science, 124(3212), pp.103- 104.[2]Bemporad, C., Gratta, G. and Vogel, P., 2002. Reactor-based neutrino oscillation experiments. Reviewsof Modern Physics, 74(2), pp.297-328.[3] Bowden, N., 2008. Reactor monitori

自从中微子的第一个实验检测以来，随着1950年代的Cowan-Reines实验，核试验反应器在中微子物理学领域起着核心作用，作为电子中微子的来源。可以通过β衰减反应检测到这些电子抗中神经，[1]，是由核心内酯在核心内裂变形成的富含中子核的β衰变。结果，这种电子抗神经通量与A反应器的运行固有相关，并且与反应堆的功能和其核心的果实库存有关[2]。赋予对反应器的操作参数的依赖性和对反应器的裂变库存的依赖，最近才能监控反应器的概念，但仅在某些时间内就已经存在了某些时间，但它的理解是在某些时期的理解。 [3]。与当前的IAEA程序相比，基于反中文的核燃料的抗抑郁措施允许对核燃料的批量核算，从而估算了对物品质量的假设产生的大量裂变材料的估计。另外，通过在与反应器的秒距离内使用检测器并允许对核心的实时测量进行抗抑郁方法，这是通过核心的实时测量。实验表明，与在较大的隔离距离（例如在thekamland实验中[4] [5]）相比，中性衰减对通量的影响大大降低了通量的影响。虽然通过中微子检测对核反应堆进行远面的现场监测是令人难以置信的前景，但中微子混合的贡献和频谱的增加的贡献极大地粘酶供应建模的复杂性。用于反应器监测的电子抗中性光谱的复杂性是依赖于偏离的预期通量和能量光谱。因此，需要与测得的速率进行比较，通过统计方法，模型从模型的明显偏差以及检测到这种偏差所需的时间范围进行比较，需要建立抗神经模型的阈值[6]。运营数据由Hartlepool等核反应堆以及耗资燃料库存提供。这些来源术语将​​征用，包括在不同的距离时向探测器提供通量事件的估算，即以一定的方式考虑了这种通量的中微子混合以及实时的核心核心的预期演变，即现有应用程序（例如Geo-neutrinos [7]）的现有应用程序[7]，因此不考虑ave and avery。这些现象包括在5 MeV处检测到的抗中性菌的意外现象，其原因是未知的原因，某些原因是由于中微子诱导的Deuteron崩解或相干性弹性弹性中性核核腐蚀性，例如某些原因是由于某些造成的托架。此外，另一种可能对研究的异常是，在短基线实验中预期的反应抗反应型中的事件下降[9] .2参考文献[1] Cowan，C。，Reines，F.，Harrison，F.，Harrison，F.，Kruse，H。and McGuire，H。和McGuire，A.，1956年，1956年。检测免费中子：确认：一个确认。科学，124（3212），第103-104页。[2] Bemporad，C.，Gratta，G。和Vogel，P.，2002。基于反应堆的中微子振荡实验。现代物理学的评论，74（2），第297-328页。[3]鲍登（N.