The Safe Storage of Plutonium Oxide

钚材料的安全和可靠储存是一个国际关注的问题，全世界储存了约250吨分离钚。其中一半以上来自约50年的民用核燃料后处理，长期储存在联合王国，而政府正在考虑其最终处理和处置的选择。这种钚以煅烧过的PuO2粉末的形式储存在嵌套的密封钢储存罐中。在某些情况下，可能会发生气体生成，随之而来的是储存包装加压。在实践中，这是很少看到的，经验得出的标准用于保持安全的储存条件。尽管如此，这是一种在实践中必须避免的潜在情况-因此，必须了解可能导致增压的基本机制。提出了5条主要途径：（i）α衰变的氦积累;（ii）高分子填充材料的分解;（iii）吸湿的PuO_2由于自加热而脱附H_2O产生的蒸汽;（iv）吸附水的辐解;并且，在本发明中，（v）通过PuO2与H2O的化学反应产生H2。（Transformative Science & Engineering for Nuclear Decommissiong）联合会（www.example.com）。该项目是兰开斯特大学、国家核实验室（NNL）和塞拉菲尔德有限公司之间的合作，旨在了解这些机制中的第一种机制，即α衰变产生的氦，可能在加压中发挥的作用。创新的样品制备和热/重量分析方法的研究将首先在大学开发，然后部署在真实的样品在NNL。生成的数据和知识将通过NNL传输到塞拉菲尔德有限公司，并用于更好地支持钚储存安全案例。该奖学金是作为"增长核能可靠经济能源技能"（GREEN）博士培训中心（https：//www.nuclear-energy-cdt.manchester. ac. uk/）的一部分提供的，该中心是兰开斯特、曼彻斯特、利物浦、利兹和谢菲尔德大学之间的合作项目。GREEN旨在开发和提供解决整个燃料循环核能领域关键挑战所需的研究和技能。

The safe and secure storage of plutonium (Pu) materials is a matter of international concern with ~250 tonnes of separated Pu stockpiled worldwide. Over half of this, resulting from ~50 years civil nuclear fuel reprocessing, is in long term storage in the UK whilst the Government considers options for its final treatment and disposition. This Pu is stored as calcined PuO2 powder in nested, sealed steel storage cans. Under certain circumstances, gas generation may occur with consequent storage package pressurisation. In practice, this is rarely seen and empirically derived criteria are used to maintain safe storage conditions. Nonetheless, this is a potential scenario that must be avoided in practice - thus the fundamental mechanisms that could lead to pressurisation must be understood. 5 main routes have been suggested:(i) Helium accumulation from alpha decay;(ii) Decomposition of polymeric packing material;(iii) Steam produced by H2O desorption from hygroscopic PuO2 due to self-heating;(iv) Radiolysis of adsorbed water; and,(v) Generation of H2 by chemical reaction of PuO2 with H2O.The last 4 mechanisms are being studied as part of the work of the EPSRC TRANSCEND (TRANSformative SCience & Engineering for Nuclear Decommissiong) consortium (www.transcendconsortium.org). This project, a collaboration between the University of Lancaster, the National Nuclear Laboratory (NNL) and Sellafield Ltd, seeks to understand the role that the first of these mechanisms, helium from alpha decay, might play in pressurisation. Innovative sample preparation and thermal / gravimetric analysis methods for the study of this will first be developed at the university and then deployed on real samples at NNL. Data & knowledge generated will be transferred to Sellafield Ltd via the NNL and used in better underpinning of the Pu storage safety cases.This studentship is offered as part of the "Growing skills for Reliable Economic Energy from Nuclear" (GREEN) Centre for Doctoral Training (https://www.nuclear-energy-cdt.manchester.ac.uk/), a collaboration between the Universities of Lancaster, Manchester, Liverpool, Leeds and Sheffield. GREEN aims to develop and deliver the research and skills required to address key challenges in the field of nuclear energy across the entire fuel cycle.