CHaracterisation, Imaging and MaPping of fuel debris for safe retrieval (CHIMP)

用于安全检索的燃料碎片的表征、成像和绘图 (CHIMP)

基本信息

批准号：
EP/R01924X/1
负责人：
Claire Louise Corkhill
金额：
$ 32.27万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR01924X%2F1
关键词：
CHaracterisation Imaging MaPping fuel debris

项目摘要

This research is a joint UK and Japan effort to support ongoing clean-up operations at the Fukushima Daiichi Nuclear Power Plant (NPP). On March 11 2011, the tsunami that engulfed the Fukushima Daiichi NPP resulted in a loss of coolant accident and the partial meltdown of boiling water reactor Units 1 - 3. Immediately after the meltdown, seawater was injected into the high-temperature reactor cores for emergency cooling, however this was not sufficient and temperatures rose in excess of 2000C, causing pellets of UO2 nuclear fuel to melt and react with steam-oxidised zircaloy fuel cladding. The resulting material is highly hazardous and comprises a mixture of UO2 fuel, zirconium from the cladding and other melted reactor components, such as concrete and steel from the fuel pressure containment vessel. These materials are known as fuel debris and corium and are highly radioactive since they also incorporate fission products and minor actinides (e.g. plutonium) from the fission of the fuel. Since the accident, water has been continuously injected to the reactor, which has successfully cooled the fuel debris and corium. In this so-called "stable cold shutdown condition", analysis of coolant water effluent has been shown to contain plutonium, which indicates that the fuel debris is being dissolved. This has prompted significant efforts to retrieve the fuel debris and corium from the reactors, but before any plans for retrieval can be made, and technologies selected to safely undertake the retrieval operations, it is necessary to understand: 1) the chemical and physical properties of the fuel debris and corium; and 2) where the fuel debris and corium reside within the reactor.Because this material is not found in 'normal' nuclear decommissioning operations, and because it is not possible to enter the reactor to take samples, or to locate its position due to the extreme radiation field, other solutions are required. In this research project, we will make surrogate fuel debris and corium materials using UO2 doped with "cold" fission product analogues (e.g. stable isotopes), melted together with zirconium cladding and other reactor component materials (e.g. concrete and steel). In comparison with real fuel debris and corium, these will be safe to handle in the laboratory. By analysis of these materials, which will be the most realistic fuel debris and corium simulants created to date, we will build an understanding of their properties, which will support the choice of decommissioning methodologies (e.g. which type of robot and cutting tool) and how to handle the materials once they have been retrieved from the reactor. These materials will also be used to validate two important techniques currently under development by our Japanese project partners to retrieve fuel debris and corium from the reactors. The first is an on-site remote 3D imaging technique, capable of identifying the type of radioactive elements in any given piece of fuel debris or corium within the reactor, without direct contact. It is proposed to test this method during our project at the Fukushima Daiichi NPP. The second is a statistical mapping model, which will use input from the characterisation of our simulant fuel debris and corium materials, combined with data from the gamma radiation emission from the fuel debris within the Fukushima Daiichi NPP, to make a predictive map of where the fuel debris and corium reside within the reactor. This model, our materials and the collaboration between UK and Japan partners in this project, will strongly support the planning and implementation of safe fuel debris retrieval operations, which are due to begin in 2021.

这项研究是英国和日本共同努力的结果，旨在支持福岛第一核电站 (NPP) 正在进行的清理作业。 2011年3月11日，席卷福岛第一核电站的海啸导致冷却剂流失事故，沸水堆1-3号机组部分熔毁。熔毁后，立即向高温堆堆芯注入海水进行应急处理。冷却，但这还不够，温度上升超过 2000°C，导致 UO2 核燃料颗粒熔化并与蒸汽氧化反应锆合金燃料包壳。产生的材料具有高度危险性，由二氧化铀燃料、包壳中的锆和其他熔化的反应堆组件（例如燃料压力安全壳中的混凝土和钢材）组成。这些材料被称为燃料碎片和真皮，具有高放射性，因为它们还包含来自燃料裂变的裂变产物和次锕系元素（例如钚）。事故发生以来，不断向反应堆注入水，成功冷却了燃料碎片和真皮。在这种所谓的“稳定冷停机条件”下，对冷却水流出物的分析表明含有钚，这表明燃料碎片正在溶解。这促使人们付出巨大努力从反应堆中回收燃料碎片和真皮，但在制定任何回收计划以及选择安全进行回收操作的技术之前，有必要了解：1）燃料碎片和真皮； 2) 燃料碎片和真皮存在于反应堆内。因为这种材料在“正常”核退役操作中不会被发现，而且由于无法进入反应堆取样或定位其位置，极端辐射场，需要其他解决方案。在这个研究项目中，我们将使用掺有“冷”裂变产物类似物（例如稳定同位素）的二氧化铀来制造替代燃料碎片和真皮材料，并与锆包壳和其他反应堆组件材料（例如混凝土和钢）熔化在一起。与真实的燃料碎片和真皮相比，这些在实验室中处理是安全的。通过对这些材料的分析（它们将是迄今为止创建的最真实的燃料碎片和真皮模拟物），我们将了解它们的特性，这将支持退役方法的选择（例如哪种类型的机器人和切削工具）以及如何从反应堆中取出材料后对其进行处理。这些材料还将用于验证我们的日本项目合作伙伴目前正在开发的两项重要技术，以从反应堆中回收燃料碎片和真皮。第一种是现场远程 3D 成像技术，能够识别反应堆内任何给定燃料碎片或真皮中的放射性元素类型，而无需直接接触。建议在福岛第一核电站的项目期间测试该方法。第二个是统计测绘模型，该模型将使用模拟燃料碎片和真皮材料的特征输入，结合福岛第一核电站内燃料碎片的伽马辐射发射数据，绘制预测图，显示燃料碎片和真皮存在于反应堆内。该模型、我们的材料以及英国和日本合作伙伴在该项目中的合作，将有力支持安全燃料碎片回收行动的规划和实施，该行动将于 2021 年开始。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Chemical state mapping of simulant Chernobyl lava-like fuel containing material using micro-focused synchrotron X-ray spectroscopy.

DOI：
10.1107/s1600577521007748
发表时间：
2021-11-01
期刊：
Journal of synchrotron radiation
影响因子：
2.5
作者：
Ding H;Dixon Wilkins MC;Mottram LM;Blackburn LR;Grolimund D;Tappero R;Nicholas SL;Sun S;Corkhill CL;Hyatt NC
通讯作者：
Hyatt NC

Synthesis, characterisation and preliminary corrosion behaviour assessment of simulant Fukushima nuclear accident fuel debris

模拟福岛核事故燃料碎片的合成、表征及初步腐蚀行为评估