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，该联盟开发了一个大型中微子探测器，作为日本T2 K国际实验的一部分。利物浦小组认为，为这项国际工作开发的技术可以用来制造一个占地面积小、高度可靠的探测器，以探测从运行中的核裂变反应堆堆芯发射的反中微子。当与反应堆功率输出相关时，测量来自发电站的反中微子排放的数量和能量水平是检测未宣布的关闭以及高等级核材料是否已被秘密地从过程中移除的非常有效的方法，为T2 K实验建造的探测器是一个采样电磁热量计（ECal），围绕近探测器的中微子目标探测器子系统。它是基于层挤压塑料闪烁体棒与铅片夹在他们之间。它为所有离开或进入近探测器的粒子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道和能量沉积进行成像。该系统已证明了从带电粒子到~ 200 keV的能量沉积的检测。在距离棒的末端1米处的大的光产量已经通过将棒的波长转移纤维的中心穿线来实现，以收集产生的光并将其传输到称为MPPC的固态光子检测设备。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，超过10%，并且在整个检测器中几乎没有死通道（20，000个中约有50个死通道），非常可靠和坚韧。该项目的设计和量热能力已经在T2 K项目中得到了证明，最近的日本地震（2011年）证明了探测器的鲁棒性。该项目重复使用了T2 K的许多备用电子元件。对于反应堆监测器探测器，ECal设计已被重新配置为反中微子探测，用钆取代铅。钆被用来捕获在反中微子相互作用中产生的中子。当一个中子被钆原子核捕获时，它会产生一个大的光子簇射（~8 MeV），在探测器中留下一个独特的信号。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。该装置已在利物浦大学的实验室中使用各种放射源进行测试。为了在现实条件下测试该设备并推进该项目，我们建议将探测器部署在商业核反应堆上。在联合王国向原子能机构和能源与气候控制部提供的保障监督支助方案的帮助下，就探测器的部署进行了谈判。一旦取得成功，该小组将寻求与原子能机构一起开始实地试验。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，作为原子能机构确保和平利用核材料努力的一部分。