The impact of polyacrylamide radiolytic and microbial degradation products on the interim and long term storage on radwaste

聚丙烯酰胺已被认为是一种潜在的沉降助剂，可以通过絮凝塞拉菲尔德现场的一系列遗留燃料材料来改善污泥沉降操作。微生物将聚合物材料分解成可能被产甲烷菌消耗的基质，产生甲烷和二氧化碳。聚丙烯酰胺预计将增加微生物数量并增加此类气体的产生，同时还提供放射分解和生物降解途径以生产可以螯合和移动被判处长期地质处置的放射性核素的材料。了解辐射分解和微生物降解产物和动力学将为工程设计能力提供信息，并告知退役和处置利益相关者如何在核退役操作中应用此类试剂并管理风险。这个跨学科研究项目将结合地球微生物学、微生物基因组学、有机化学、放射化学和辐射科学，并将使用最先进的技术，包括微生物和 DNA 测序分析、光学和电子显微镜、XRF、XAS、共聚焦显微镜、ESEM 和 TEM，研究批量实验室孵化中聚丙烯酰胺的（生物）降解。成功的申请者将加入由 40 名跨学科研究人员组成的欢迎队伍，他们在地球与环境科学系最近翻新且位于同一地点的两个中心工作，由 PI 和联合导师（Lloyd、Morris、van Dongen 和 Shaw）共同领导。学生将可以使用威廉姆森分子环境科学研究中心（WRC；由劳埃德领导）内的大型专用实验室，该实验室拥有最先进的分子环境研究设备，并与由莫里斯领导的价值 400 万英镑的新 NNUF RADER 实验室 (https://www.nnuf.ac.uk/rader) 毗邻，为处理和分析核环境系统中的放射性核素提供了独特的补充设施。学生还将受益于与道尔顿坎布里亚设施 (DCF) 进行聚丙烯酰胺辐照研究的联系。

Polyacrylamide has been identified as a potential settling aid which can improve sludge settling operations by flocculating a range of legacy fuel materials on the Sellafield site. Microbes break down polymeric material into substrates which may potentially be consumed by methanogens, producing methane and carbon dioxide. Polyacrylamide is expected to increase the microbial population and increase the generation of such gases, while also providing radiolytic and biological degradation paths to produce material which could chelate and mobilse radionuclides sentenced to a long-term geological disposal. Understanding the radiolytic and microbial degradation products and kinetics will inform engineering design capability, and inform decommissioning and disposal stakeholders how to apply and manage risk regarding the application of such reagents in nuclear decommissioning operations. This interdisciplinary research project will combine geomicrobiology, microbial genomics, organic chemistry, radiochemistry, and radiation science, and will study polyacrylamide (bio)degradation in batch laboratory incubations using state of the art techniques including microbial and DNA sequencing analysis, light and electron microscopy, XRF, XAS, confocal microscopy, ESEM, and TEM. The successful applicant will join a welcoming cohort of 40+ interdisciplinary researchers working in two recently refurbished and co-located centres in the Dept of Earth and Environmental Sciences, co-directed by the PI and co-supervisors (Lloyd, Morris, van Dongen and Shaw). The student will have access to a large suite of dedicated laboratories within the Williamson Research Centre for Molecular Environmental Sciences (WRC; directed by Lloyd), which houses state of the art equipment for molecular environmental studies and sits alongside the new £4M NNUF RADER labs (https://www.nnuf.ac.uk/rader) directed by Morris, offering unique complementary facilities for handling and analysing radionuclides in nuclear environmental systems. The student will also benefit from links to the Dalton Cumbrian Facility (DCF) for irradiation studies on polyacrylamide.