2017-12 - Combined SMR Systems GFA Final

There seems a clear need for a methodology for evaluating the claims of ‘new’ reactor systems at a strategic level, to ensure that the claims of ‘good’ for the systems are considered alongside the ‘bad’ and the ‘ugly’. This should extend to examining which are the energy futures which will extract value from any given system’s characteristics, and which futures will reduce or remove a system’s attributes as drivers for deployment. The common method of comparing complex systems is to use Multi-Attribute Decision Analysis (MADA). In this method a group of attributes are defined to cover the main parameters of the systems, and scores are allocated depending on how well or badly a system performs. Not all parameters will be deemed to carry the same importance, so the ‘scores’ which have been compiled are ‘weighted’ by a set of ‘weighting values’, and the ‘weighted scores’ added to provide an overall ‘consolidated score’ for the particular system. In 2012-2013, the National Nuclear Laboratory developed a MADA system to examine nuclear power systems, based on 42 metrics derived from those used by the Generation IV International Forum. These were subsequently divided into seven groups (Cost, PRPP, Safety, Strategic, Deployability, Sustainability, Waste) and used to assess advanced reactor systems. The approach suffered from two main disadvantages: 1. The use of a MADA with a large number of metrics makes the result very difficult to communicate meaningfully, even to committed stakeholders – there is often a shared understanding by ‘those that were in the room for the analysis’, which fails to be transferable to others. 2. The suitability of a reactor system depends very strongly on ‘the world in which it must operate’. For example, high scores for uranium economy (e.g. fast reactors) should be highly weighted in a ‘uranium scarce’ future, but will not feature in a ‘uranium plentiful and cheap’ future. Subsequently, joint working by the Dalton Nuclear Institute, IDM and NNL addressed the weaknesses of the MADA approach to evolve the Generic Feasibility Assessment technique. The key change was the recognition that, in the UK and other states with well-established nuclear programmes, safety, environmental and proliferation/security attributes are all covered by well-developed regulatory regimes – so that reactor system deployment is not about “how safe, secure, and environmentally benign” a system is – but rather how much time and effort must be expended to allow the system to conform with this tried and tested regulatory framework. Generic Feasibility Assessment has been applied to several advanced reactor systems (see Nuclear System Assessment). GFA was also used on the assessment of Small and Modular Reactors using Emerging Technologies which was carried out for the Department of Energy and Climate Change by the National Nuclear Laboratory, Integrated Decision Management Ltd and Dalton in 2015/16 (see Techno-Economic Assessment).当前亟需一套可在战略层面评估新型反应堆系统各项宣称的方法论，以确保在评判该类系统时，能兼顾其“优势”、“劣势”与“隐忧”。该方法论还应覆盖两类能源未来场景的研判：一类是能依托特定反应堆系统特性实现价值提取的场景，另一类是会削弱或消除该系统作为部署动因之属性的场景。 当前对比复杂系统的通用方法为多属性决策分析（Multi-Attribute Decision Analysis, MADA）。该方法会先定义一组覆盖系统核心参数的属性维度，再根据系统的性能表现分配对应分值。由于并非所有参数的重要程度均一致，因此需通过一组权重值对已汇总的分值进行加权处理，最后将加权分值相加，即可得到该特定系统的综合总分。 2012至2013年间，国家核实验室（National Nuclear Laboratory, NNL）基于第四代国际论坛（Generation IV International Forum）所采用的42项指标，开发了一套用于评估核电系统的多属性决策分析系统。后续该系统被划分为七个类别：成本（Cost）、PRPP、安全（Safety）、战略（Strategic）、部署性（Deployability）、可持续性（Sustainability）以及废物（Waste），并被用于先进反应堆系统的评估工作。但该方法存在两大主要缺陷： 1. 采用包含大量指标的多属性决策分析体系，导致评估结果难以实现有效传播，即便对积极参与的利益相关方亦是如此——通常仅参与本次分析的人员能达成共识，该共识无法向其他群体迁移推广。 2. 反应堆系统的适配性高度依赖其运行所处的外部环境。例如，铀经济性（如快中子反应堆）的高评分，在“铀资源稀缺”的未来场景中应被赋予极高权重，但在“铀资源充足且廉价”的场景中则无需考量。 随后，道尔顿核研究所（Dalton Nuclear Institute）、集成决策管理有限公司（Integrated Decision Management Ltd, IDM）与国家核实验室（National Nuclear Laboratory, NNL）开展联合研究，针对多属性决策分析方法的缺陷进行改进，衍生出通用可行性评估（Generic Feasibility Assessment, GFA）技术。本次改进的核心认知在于：在英国及其他拥有成熟核电规划的国家，安全、环境以及防扩散/安保属性均已由完善的监管体系覆盖，因此反应堆系统的部署核心并非评判“该系统有多安全、多可靠、多环境友好”，而是核算系统为符合这套久经考验的监管框架所需投入的时间与人力成本。 通用可行性评估技术已被应用于多款先进反应堆系统的评估（详见《核系统评估》）。 2015至2016年间，国家核实验室、集成决策管理有限公司与道尔顿核研究所受能源与气候变化部委托，开展了针对采用新兴技术的小型模块化反应堆（Small and Modular Reactors）的评估工作，本次评估亦采用了通用可行性评估技术（详见《技术经济评估》）。