NANODOT2: NANOMATERIALS FOR THE RADIOMETRIC DETECTION OF TRITIUM

该项目NANODOT2(用于氚辐射检测的纳米材料)旨在利用纳米材料制造方面的最新进展，开发一种新型原型仪器，用于分析和表征运行中核设施和退役核设施周围陆地和海洋环境中的放射性氚。NANODOT2完全属于NERC的职权范围，NANODOT2是一个由NERC资助的早期博士学位的12个月后续项目，是兰开斯特大学和混合仪器公司的合作项目，混合仪器公司是一家专门制造和销售先进辐射仪器的中小企业。氚(T)是在核反应堆的常规操作中制造的氢的放射性同位素。这可能会在乏燃料冷却池和废燃料处理和废物处理设施中产生水中氚--所有这些都是泄漏到地面和其他地方的潜在来源。水中的T以氚水HTO的形式最常见地存在于地下水中。由于T是H的同位素，HTO的行为与H2O没有区别，因此在环境中具有很强的流动性，由于HTO/H2O的当量，其运移速率与地下水的速度相同。这也使得HTO在人体组织中高度流动，并伴随着相关的健康风险--世界卫生组织饮用水中T的限值为&lt；10kBq/L。此外，尽管由于人为活动而存在的氚数量往往极低，而且很容易扩散，但氚是许多行业的关切，即海洋渔业经常需要进行广泛的清理，即使在低于可接受的法定限度的情况下也是如此。因此，迫切需要在核设施周围的陆地和海洋环境以及核设施运营/退役产生的废物中对T进行快速、准确和精确的分析。兰开斯特和混合已经合作了4年来满足这些需求。氚的衰变与软贝塔发射使得在该领域的快速辐射检测非常困难。然而，在兰开斯特与HYDER进行的非常成功的NERC/RSC ACTF博士生项目(获奖NE/H025650/1，以下简称NANODOT1)的数据提供了原理证据，即通过电解，T可以被HTO中的纳米孔钯(Pd)层选择性且可逆地隔离，然后很容易通过液体闪烁计数检测到预浓缩的T。随后由创新英国/核退役管理局资助的可行性研究(奖项131756，翠贝卡，电化学辅助放射计量学的氚检测)，也是由兰开斯特和混合公司进行的，展示了将纳米孔钯层直接耦合到固体闪烁体的可能性。这提供了一种在基于PMT的固体闪烁计数分析之前将T预先集中在闪烁体表面的方法，潜在地产生了一种用于T检测的新型辐射仪器，提供了快速、无干扰、原位检测和监测。翠贝卡还展示了这种氚传感器及其支撑技术的市场，并导致了英国专利申请GB2523732“氚测量”。NANODOT1将这项技术提升到(技术准备级别)TRL3(可行性)，而Tribeca进一步将其提升到TRL5(部件开发)。NANODOT2的目标是将这项技术带到TRL6(演示)。具体地说，我们的目标是建立一个原型仪器，该仪器基于用于贝塔辐射检测的新型钯纳米材料修饰的固体闪烁体，提供：-比当前技术更便宜、更快、更灵敏和更可靠的T检测；以及-快速、准确和精确地测量水中T，用于环境分析和核废料/工艺/流出物的表征。关键词：氚检测；环境放射性；分析科学；环境监测；纳米材料；持有者：兰开斯特大学，混合仪器

This project, NANODOT2 (NANOmaterials for the radiometric Detection Of TriTium) aims to exploit recent advances in nanomaterials fabrication to develop a novel, prototype instrument for the analysis and characterisation of radioactive tritium in the terrestrial and marine environments around both operational nuclear facilities and those in decommissioning. Falling squarely within NERC's remit, NANODOT2 is a 12 month follow project from an earlier NERC-funded PhD and is a collaboration between Lancaster University and Hybrid Instruments, an SME specialising in the manufacture and marketing of advanced radiometric instrumentation.Tritium (T) is a radioactive isotope of hydrogen made during the routine operation of nuclear reactors. This can give rise to waterborne tritium in, inter alia, spent fuel (SF) cooling ponds and SF processing & waste treatment facilities - all potential sources of leakage to ground and beyond. Waterborne T is most commonly present in groundwater in the form of tritiated water, HTO. As T is an isotope of H, HTO behaves indistinguishably from H2O and so is highly mobile in the environment, its migration rate being identical to the velocity of groundwater due to the HTO/H2O equivalency. This also makes HTO highly mobile in human tissue, with associated health risks - the WHO limit for T in drinking water is <10 kBq/L. Additionally, despite often being present in extremely low quantity as a result of anthropogenic activities and easily dispersed, tritium is a concern to many industries i.e. sea fisheries often commanding extensive clean-up even where it is present at less than accepted statutory limits.Thus there are pressing health & safety and economic needs for fast, accurate & precise analysis of T in the terrestrial and marine environments around nuclear sites and in the wastes arising from their operation/decommissioning. Lancaster and Hybrid have been working in collaboration for >4 years to address these needs.Tritium decays with a soft beta emission making rapid radiometric detection in the field very difficult. However, data from a very successful NERC/RSC ACTF PhD studentship (award NE/H025650/1, hereafter NANODOT1) conducted at Lancaster with Hybrid, provide PROOF OF PRINCIPLE that, by electrolysis, T can be selectively & reversibly sequestered by nanoporous palladium (Pd) layers from HTO, the pre-concentrated T then being easily detected by liquid scintillation counting. A subsequent InnovateUK/Nuclear Decommissioning Authority funded feasibility study (award 131756, TRIBECA, TRItium detection By Electro-Chemically Assisted radiometrics), again conducted by Lancaster & Hybrid, demonstrated the possibility of coupling nanoporous Pd layers directly to solid scintillators. This provided a means by which T could be pre-concentrated at a scintillator surface prior to analysis by PMT-based solid scintillation counting, potentially yielding a novel radiometric instrument for T detection offering fast, interference free, in situ detection & monitoring. TRIBECA also demonstrated the market for such a tritium sensor and its underpinning technology, and led to a UK patent application GB2523732 "Tritium Measurement".NANODOT1 took this technology to (Technology Readiness Level) TRL3 (feasibility) whilst TRIBECA further advanced it to TRL5 (component development). NANODOT2 aims to take the technology to TRL6 (demonstration). Specifically, we aim to build a prototype instrument that, based on a novel Pd nanomaterial-modified solid scintillator for beta radiation detection, offers:-cheaper, faster, more sensitive & more reliable T detection than current technology; and -fast, accurate & precise measurement of waterborne T for environmental analysis and nuclear waste/process/effluent stream characterisation. Keywords: Tritium Detection; Environmental Radioactivity; Analytical Science; Environmental Monitoring; NanomaterialsStakeholders: Lancaster University, Hybrid Instruments