A new concept for compact radiation shielding: Reactive sintered tungsten borocarbides

紧凑型辐射屏蔽的新概念：反应性烧结硼碳化钨

• 批准号: EP/T033592/1
• 负责人: Jessica Marshall
• 金额: $ 142.46万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT033592%2F1
• 关键词: new; concept; compact; radiation; shielding

There has been no greater existential threat to humanity to date from anthropogenic climate change as a result of CO2 emissions. The effects are already apparent in terms of more extreme weather, loss of polar ice and rising sea levels. Power generation contributes to much of the CO2 emissions from fossil fuel burning as the worldwide demand for power continues to outstrip supply. Renewable energy (wind, solar, hydro) is limited by weather dependency, with associated issues such as energy storage and land use. Nuclear fusion has a significant role in decarbonizing global power generation but radiation shielding is a limiting factor. Creating miniature Suns is one part, but materials must exist that can withstand fusion conditions for practical fusion reactors. W-based alloys and other refractory metals are current solutions in fusion reactors, but the engineering requirements for power-generating fusion reactors exceed those in current materials. The goal of this fellowship will demonstrate the feasibility of radiation shielding based on the Cemented Tungsten Carbides and Reactive Sintered Borides (cWC-RSB) concept in Compact Spherical Tokamaks (cSTs). cWC-RSBs can bridge the gap between current materials and the engineering requirements for a power-generating cST. cWCs-RSBs have excellent radiation absorption properties by combining heavy (W) and light elements (C, B) with the strength and toughness by combining WC with a ductile metal binder. However, cWCs have never been used in nuclear reactors to date since the use of Co (and Ni) metal as a binder alloy prevented the use of cWCs as radiation due to Co and Ni being activation hazards. In 2014, I discovered that non-activating FeCr alloys are suitable as cWC binder alloys, with RSB development following on investigating boron additions in cWCs. Combined cWC-RSB shields have greater radiation attenuation overall, compared to cWCs alone. The first objective evaluates the thermo-mechanical properties and the safety case for shielding candidates, including high-temperature oxidization and thermal shock to in terms of worst-case scenarios, such as exposure of hot shielding to air. Experimental data on Si-coated cWCs showed that Si-coating retarded oxidization rate by 4 orders of magnitude relative to tungsten in the temperature range 900C-1200C. I will evaluate the properties of cWC-RSBs over cryogenic to failure (> 1200C) temperatures predicted for power-generating fusion reactors. While considerable data on the thermo-mechanical properties exist for cWCs since the 1930s, there is little on RSBs, given their novelty and it is crucial that thermo-mechanical properties of RSBs are well-known prior to industrialization.The novelty of RSBs means that very little is known about their chemistry and routes to fabrication. Current processing methods are not fully optimized for dense, crack-free RSBs. The second objective aims to fill these gaps using the calculation of phase diagram method (CALPHAD) for predicting the most suitable compositions and design of experiment (DoE) methodology for the most efficient processing trials. This research demonstrates how new solutions can be derived from existing materials and techniques when a critical gap in current solutions is apparent. Recent simulations of the neutron and gamma attenuation of WC- and RSB-based shielding concepts show considerable promise. However, there is little data on the radiation response of cWCs and none on RSBs to date. For this third objective, I intend to build on current research using simulated cSTs to inform radiation experiments and experimental work simulating the range of conditions inside a cST, including ion bombardment, charged particles, and secondary radiation. Data from cWC-RSB shields in a simulated fusion reactor alongside demonstrated oxidization resistance indicates that cWC-RSB materials exceed current radiation shielding candidates in terms of radiation attenuation and safety.

由于二氧化碳排放量，由于人为气候变化，对人类的存在威胁没有更大的威胁。从更美好的天气，极地冰的丧失和海平面上升的海平面上，这种影响已经显而易见。随着全球对电力的需求持续超过供应，发电量导致化石燃料燃烧的大部分二氧化碳排放量。可再生能源（风，太阳能，水力）受到天气依赖性的限制，以及诸如储能和土地使用之类的相关问题。核融合在全球发电中具有重要作用，但辐射屏蔽是一个限制因素。创建微型太阳是一个部分，但是必须存在可以承受实用融合反应器的融合条件的材料。基于W的合金和其他难治性金属是融合反应器中的当前溶液，但是发电融合反应器的工程要求超过了当前材料中的融合反应器。该团契的目的将证明基于紧凑的球形tokamaks（CSTS）中的胶结碳化碳纤维和反应性烧结的硼化物（CWC-RSB）概念的可行性。 CWC-RSB可以弥合当前材料与发电CST的工程要求之间的差距。 CWCS-RSB具有出色的辐射吸收特性，通过将重元素（W）和光元素（C，B）与强度和韧性相结合，通过将WC与延性金属粘合剂结合在一起。但是，由于使用CO（和Ni）金属作为粘合剂合金，因此CWC从未在核反应堆中使用，这阻止了由于CO和Ni而导致的CWC作为辐射，因此CO和NI是激活危害。 2014年，我发现非激活的FECR合金适合作为CWC粘合剂合金，随后，RSB的开发在研究CWC中的硼添加。与仅CWC相比，CWC-RSB组合屏蔽总体上的辐射衰减更大。第一个目标评估了屏蔽候选者的热机械特性和安全案例，包括高温氧化和热冲击，以在最坏情况下（例如，将热屏蔽到空气暴露在内）。 SI涂层CWC的实验数据表明，相对于钨在900C-1200C的钨中，SI涂层延迟氧化速率相对于钨的数量级4个数量级。我将评估CWC-RSB的特性，而不是低温到衰竭（> 1200C）的温度，预测了发电的融合反应器。虽然自1930年代以来，CWC存在有关CWC的热机械性能的大量数据，但鉴于它们的新颖性，RSB几乎没有，并且至关重要的是，RSB的热机械特性在工业化之前是众所周知的。RSB的新颖性意味着对它们的化学和制造途径知之甚少。当前的处理方法未针对密集，无裂纹的RSB进行完全优化。第二个目标旨在使用相图法（Calphad）的计算来填补这些空白，以预测最有效的处理试验的实验（DOE）方法的最合适组成和设计。这项研究表明，当当前解决方案中的关键差距显而易见时，如何从现有材料和技术中得出新的解决方案。对基于WC和RSB的屏蔽概念的中子和伽马衰减的最新模拟显示出巨大的希望。但是，迄今为止，关于CWC的辐射响应的数据很少。对于第三个目标，我打算使用模拟的CST进行当前的研究，以告知辐射实验和实验工作，以模拟CST内部的条件范围，包括离子轰击，带电的颗粒和二次辐射。在模拟融合反应器中与CWC-RSB盾牌一起的数据表明，在辐射衰减和安全性方面，CWC-RSB材料超过电流辐射屏蔽候选者。

项目成果

Tungsten carbide for radiation shielding: A comprehensive review

用于辐射屏蔽的碳化钨：全面审查

• DOI: 10.59499/ep235765427
• 发表时间: 2023
• 作者: Srinivasan S

Proton and gamma irradiation of novel tungsten boride and carbide candidate shielding materials

• DOI: 10.1016/j.fusengdes.2023.113667
• 发表时间: 2023-03-23
• 期刊: FUSION ENGINEERING AND DESIGN
• 影响因子: 1.7
• 作者: Marshall, J. M.

Multi-Scale microscopy of Reactive sintered boride (RSB) neutron shielding materials

反应烧结硼化物 (RSB) 中子屏蔽材料的多尺度显微镜

• DOI: 10.1016/j.nme.2022.101285
• 发表时间: 2022
• 期刊: Nuclear Materials and Energy
• 影响因子: 2.6
• 作者: Marshall J

Synthesis studies of radiation dense Reactive Sintered Borides (RSB) nuclear shielding materials

辐射致密反应烧结硼化物（RSB）核屏蔽材料的合成研究

• DOI: 10.1016/j.mtcomm.2023.106765
• 发表时间: 2023
• 期刊: Materials Today Communications
• 影响因子: 3.8
• 作者: Marshall J