微堆用于微电网

 编译：镜清

2020-08-26

为什么核技术最终可与社区规模的能源系统相匹配？

我们都知道，缓解气候变化是个巨大的挑战，可能让人认为需要大规模的解决方案。但今年早些时候发表在《科学》(Science)杂志上的一篇论文，探讨了“颗粒”技术可能更适合应对全球脱碳的挑战。

这里，颗粒技术的定义为物理尺寸和成本都较小、模块化且构建速度快的技术。作者从成本、快速部署、摆脱技术困境和社会合法性等10个指标，对能源技术进行了评级，发现颗粒技术总体表现更好。值得注意的是，传统核能是“块状”技术的典型代表，与颗粒相反，非常巨大、昂贵，并且建造耗时长达10年。但是，新的、小于10 MWe级的核反应堆，即所谓的微(型反应)堆，可能会打开新的市场(和新的思维方式)。

微堆不仅是小型、模块化的反应堆(SMR)，还代表核能历史上部署方式的“阶跃”。拟建微堆的独特属性包括：集成式的汽轮机、反应堆运动部件最少、可通过铁路或卡车运输、堆芯寿命较长、运行自动化或人员配备最少。最重要的是，微堆可以在中心设施生产，然后运到最终安装地点，无需在现场装卸燃料。这就为这种“即插即用”技术的融资和业主身份开辟了新范式。

美国“桑迪”飓风和加州野火等事件，促使许多社区在与主电网保持连接的同时，发展微电网。2019年微电网安装创纪录。目标是提高社区电力系统的可靠性，大电网出现故障时能与它“隔离”。然而，因为最关注可靠性，几乎90%的微电网都由化石燃料电厂供电。在将来，小型核反应堆可能成为最适合当地、可靠、低碳微电网的最佳选择，而且这项技术的准备，很可能比想象的更快。

今年3月，欧克陆公司（Oklo） 向美国核管理委员会提交1.5 MWe的奥罗拉核电站(Aurora)建造与运行联合许可证申请。西屋电气公司也对微堆设计的预申请活动大为赞赏。在加拿大，两个不同的微堆开发商正在进行“取照前”的供应商设计审查。需要多长时间还不确定，但由于规模相当小，有可能在五年内开工建设。由于成本高，首批商业建造的微堆可能不申请接入大电网。

大多数微堆开发商都在寻找客户支付高额电费的“机会”市场：没有接通电网、依赖柴油发电的社区。加拿大政府2011年进行的研究发现，290多个没有接通电网的社区，人口总数近20万。这些社区的化石燃料发电的装机容量平均只有1.8 MW。澳大利亚能源委员会2015年的一份报告发现，1000多个岛屿的供电系统和微电网，为45万人口提供服务。与加拿大类似，几乎所有的社区都依赖化石燃料（特别是柴油）发电。澳大利亚的远离电网的社区，看到可再生能源日益普及，但间歇性的可再生能源在保持电网稳定性和可靠性方面，存在重大的挑战。（沿海与近海岛屿，太阳能发电设施腐蚀也降低了使用寿命。）

微堆的另一个明显、潜在的“机会”市场是军事设施，包括国内基地和作战前沿阵地。美国《2010年国防授权法案》指示能源部长进行研究，评估为军事设施部署核能的可行性。今年3月，美国国防部批准三份合同(价值$1200-1400万)，开发“移动式”微堆设计。虽然军方过去一直是技术创新的推动力量，但也有人怀疑这种模式是否适用于微堆。

有很多原因使民用微堆的发展与军事应用脱钩，但最初可能是价值观和优先级不同。军事基地和小型社区对小型核反应堆的要求可能非常不同。民用核技术的开发应该在潜在客户的持续参与下进行，不试图让一项军事技术适应商业市场。最重要的是，微堆的许可和首次示范，需要高度透明，使公众信任这项新技术。与其指望通过慷慨的国防合同，快速实现微堆商业化，不如耐心对待一个开放和民主的技术开发和示范过程。

附：原文

Good Energy Collective

Microreactors for Microgrids?

by Jessica Lovering

August 5, 2020

Why nuclear technology might finally be a match for community-scale energy systems。

We all know that mitigating climate exchange is going to be a huge challenge, and that may lead people to think we need large-scale solutions. But a paper published in Science earlier this year looked at how “granular” technologies might be more appropriate to meet the challenge of global decarbonization.

Here granular is defined as technologies that are small in both physical size and cost, that are modular and fast to build. The authors rated energy technologies across 10 metrics of cost, rapid deployment, escaping technological lock-in, and social legitimacy, and they found that granular technologies generally performed better. Notably, traditional nuclear power was a prime example of a “lumpy” technology—the opposite of granular—very large, expensive, and taking up to a decade to build. But a new class of nuclear reactors less than 10MWe, so-called microreactors, could open up new markets (and new ways of thinking).

Microreactors are not simply tiny Small Modular Reactors (SMRs), but represent a step-change in the way nuclear power has been deployed historically. Unique attributes of proposed microreactors include integrated steam turbine, minimal moving parts in reactor, transportable by rail or truck, long core lifetimes, and autonomous operation or minimal staffing. Most importantly, microreactors can be manufactured at a central facility and shipped to the final location ready to install, with no need for on-site fuel handling. This could open up new models for financing and ownership for such a “plug-and-play” technology.

Events like Hurricane Sandy and wildfires in California have motivated many communities to develop microgrids, while remaining connected to the main power grid. In the United States, 2019 was a record year for microgrid installations. The goal is better reliability and the ability to isolate the community’s power system if the larger grid goes down. Yet because of this focus on reliability, almost 90% these microgrids are powered by fossil fuels. In the future, small nuclear reactors could be a perfect fit for local, reliable, low-carbon microgrids, but when will the technology be ready? Sooner than you may think.

In March of this year, Oklo Inc. submitted a combined license application to the US Nuclear Regulatory Commission for their 1.5MWe Aurora powerhouse. Westinghouse has commended pre-application activities with the NRC for their microreactor design. In Canada, two different microreactor developers are in the process of pre-licensing vendor design review. It’s uncertain how long the licensing process will take in either country, but because of their relatively small size, it’s not unreasonable that we might see construction start within five years. But these first commercial builds of these microreactors likely won’t be for on-grid applications, due to high costs.

Most microreactors developers are seeking niche markets where customers are paying high rates for electricity: off-grid, diesel-dependent communities. A 2011 study conducted by the Canadian Government found over 290 off-grid communities, with a collective population of almost 200,000. The average fossil-fueled powered generator capacity of these communities was just 1.8MW.  A 2015 report commissioned by the Australian Energy Council found over 1000 islanded electricity systems and microgrids across Australia, serving a population of 450,000. Similar to Canada, almost all of these communities are dependent on fossil fuels for their electricity. Australia’s off-grid communities are seeing growing penetrations of renewables, but there are significant challenges in maintaining grid stability and reliability with intermittent renewables.

Another obvious potential niche market for microreactors is military installations, both domestic bases and forward operating bases. The 2010 National Defense Authorization Act directed the Secretary of Energy to conduct a study evaluating the feasibility of deploying nuclear power for military installations. In March of this year, the US Department of Defense awarded three contracts (ranging from $12 million to $14 million each) to develop a mobile microreactor design. And while the military has been a driving force in innovating new technologies in the past, we should question this model for microreactors.

There are many reasons to decouple civilian microreactor development from military applications, but the first may be a difference of values and priorities. Military bases and small communities likely want very different attributes from a small nuclear reactor. Rather than trying to make a military technology fit into commercial markets, civilian nuclear technologies should be developed with continuous engagement from potential customers. Most importantly, the licensing and first demonstrations of microreactors will need to be completed with the highest level of transparency for the public to trust this new technology. Rather than hope to fast-track commercialization of microreactors through a generous defense contract, we should be patient with an open and democratic process of technological development and demonstration.