Monitoring Reactors for Nuclear Safeguards with T2K Technology

利用 T2K 技术监测反应堆的核保障

• 批准号: ST/M000168/1
• 负责人: Jonathon Coleman
• 金额: $ 15.19万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FM000168%2F1
• 关键词: Monitoring; Reactors; Nuclear; Safeguards; T2K

Over the last 6-7 years STFC has lead an academic consortium that has developed a large neutrino detector as part of an international experiment in Japan called T2K. The Liverpool group believe that the technology developed for this international work can be adapted to make a small footprint, highly reliable, detector to characterise the anti-neutrinos that are emitted from the core of operational nuclear fission reactors. Measuring the quantity and energy level of anti-neutrino emissions from a power station when correlated to the reactor power output is a very effective way of detecting undeclared shut-downs and whether or not high grade nuclear material has been covertly removed from the process, and so an ideal way for the IAEA to detect malpractice.The detector built for the T2K experiment is a sampling Electromagnetic Calorimeter (ECal) surrounding the neutrino target detector sub-systems of the near detector. It is based on layers of extruded plastic scintillator bars with Lead sheets sandwiched between them. It provides near-hermetic coverage for all particles exiting or coming into the near detector. This highly segmented system's function is to image tracks and energy deposition from particles produced in neutrino interactions. The detection of energy deposition from charged particles down to ~ 200 keV has been demonstrated with the system. Large light yield at 1 m away from the end of the bar has been achieved by threading the centres of the bars wavelength shifting fibres to collect the light produced and transport it to solid state, photon detecting devices called MPPCs. MPPCs give very good reproducibility of performance to better than 10% across the whole system and operation over long period of time (a few years) and are incredibly reliable and tough with few dead channels in the whole detector (~50 dead out of 20,000). For the project the design and calorimetric capabilities have already been proven in the T2K project, the recent earthquake in Japan (2011) is testament to the robustness of the detector. The project reuses many of the spares electronics components from T2K. For the reactor monitor detector, the ECal design has been reconfigured for anti-neutrino detection by replacing the lead with the gadolinium. The gadolinium is used to capture the neutrons produced in anti-neutrino interactions. When a neutron is captured by a gadolinium nucleus a large shower (~8 MeV) of photons it created leaving a unique signal in the detector. By correlating this unique neutron signal with an earlier positron signal we can efficiently select anti-neutrino interactions. The device has been testing in the laboratories at the University of Liverpool using various radio-active sources. In order to test the device in realistic conditions and advance the project, we propose to deploy the detector at a commercial nuclear reactor. Deployment of the detector has been negotiated with the aid of The UK Safeguards Support programme to the IAEA and the Department of Energy and Climate Control. Upon the successful outcome of the group will seek to start field tests with the IAEA. If the field tests are successful reactor monitoring detectors will be deployed at reactors around the world as part of the IAEA's efforts to ensure peaceful use of nuclear material.

在过去的 6-7 年里，STFC 领导了一个学术联盟，该联盟开发了一种大型中微子探测器，作为日本 T2K 国际实验的一部分。利物浦小组相信，为这项国际工作开发的技术可以用来制造占地面积小、高度可靠的探测器，以表征从运行的核裂变反应堆核心发射的反中微子。当与反应堆功率输出相关时，测量发电厂的反中微子排放量和能量水平是检测未宣布的关闭以及高级核材料是否已从过程中秘密移除的非常有效的方法，以及这是国际原子能机构检测不当行为的理想方式。为T2K实验建造的探测器是一个采样电磁热量计（ECal），围绕着近探测器的中微子目标探测器子系统。它基于多层挤压塑料闪烁体棒，其间夹有铅片。它为所有离开或进入近距离探测器的颗粒提供近乎密封的覆盖。这个高度分段的系统的功能是对中微子相互作用中产生的粒子的轨迹和能量沉积进行成像。该系统已证明可以检测低至约 200 keV 的带电粒子的能量沉积。通过在距离棒末端 1 m 处穿入波长移动光纤来收集产生的光并将其传输到称为 MPPC 的固态光子检测装置，可以实现距离棒末端 1 m 处的大光输出。 MPPC 在整个系统和长时间（几年）运行中提供了非常好的性能再现性，优于 10%，并且非常可靠和坚固，整个探测器中几乎没有死通道（20,000 个中大约有 50 个死通道） 。对于该项目，设计和量热能力已在 T2K 项目中得到验证，最近日本发生的地震（2011 年）证明了探测器的稳健性。该项目重复利用了 T2K 的许多备用电子元件。对于反应堆监测探测器，ECal 设计已重新配置，用于反中微子探测，用钆代替铅。钆用于捕获反中微子相互作用中产生的中子。当中子被钆核捕获时，它会产生大量光子（约 8 MeV），并在探测器中留下独特的信号。通过将这种独特的中子信号与早期的正电子信号相关联，我们可以有效地选择反中微子相互作用。该设备已在利物浦大学的实验室中使用各种放射源进行了测试。为了在现实条件下测试该装置并推进项目，我们建议将探测器部署在商用核反应堆上。在英国向国际原子能机构和能源与气候控制部提供保障支持计划的帮助下，已就探测器的部署进行了谈判。一旦取得成功，该小组将寻求与国际原子能机构一起开始现场测试。如果现场测试成功，反应堆监测探测器将部署在世界各地的反应堆上，作为国际原子能机构确保和平利用核材料努力的一部分。