Source: Power Magazine | Sonal Patel | November 1, 2018

As the hubbub of interest and activity surrounds development of small modular reactors (SMRs) hovering between 60 MW and 300 MW, and medium-sized nuclear reactors of under 700 MW, several nuclear technology vendors have quietly been developing micro-reactors—which are of 10 MW or less. According to the Nuclear Energy Institute (NEI), it’s highly possible that a first-of-its-kind micro-reactor could be successfully deployed at a domestic U.S. defense installation by the end of 2027.

Figure 1_Sanmen_SNPTC

1. First AP1000 starts operation. On October 11, Westinghouse Electric Co., and its customers China State Nuclear Power Technology Corp. (SNPTC) and CNNC Sanmen Nuclear Power Co. announced the world’s first AP1000 plant in Sanmen, Zhejiang Province, China, is fully operational. Sanmen 1 is one of six nuclear units featuring AP1000 reactor technology that are progressing through construction, testing, and startup. The others are Sanmen 2; two units in Haiyang, in China’s Shandong Province; and Plant Vogtle Units 3 and 4 in the U.S., which recently received partner approval to continue construction despite cost overruns. Courtesy: SNPTC

Since the 1950s, when nuclear power generation became established, the size of reactor units has evolved from 60 MW to more than 1,600 MW. In June, China General Nuclear Power Corp., for example, grid-connected Taishan 1, the world’s first EPR, a 1,600-MW third-generation pressurized water reactor (PWR) developed by French companies EDF and Framatome. On October 11, Westinghouse and China State Nuclear Power Technology Corp. also launched commercial operation of Sanmen 1 (Figure 1), the first 1,000-MW AP1000 reactor, which is also a third-generation two-loop PWR.

But interest in smaller power reactors has also grown in recent decades, due partly to high capital costs associated with large power reactors and the need to serve smaller grids. According to the World Nuclear Association (WNA), only three small reactors currently operate around the world today: a 300-MW CNP-300 in Pakistan; a 220-MW PHWR-220 in India; and an 11-MW EGP-6 at the Bilibino cogeneration plant in Siberia.

Among small reactor designs under construction are the 35-MW KLT-40S and 50-MW RITM-200 in Russia; the 27-MW CAREM-25 in Argentina; and two 250-MW HTR-PM units and the 60-MW ACPR50S in China. Development is well-advanced for 10 other reactor designs, including NuScale’s 60-MW SMR, Holtec’s 160-MW SMR-160, and Terrestrial Energy’s 192-MW molten salt reactor. Despite the simplicity of their designs, however, commercialization of SMRs has been slow, mainly due to licensing challenges, noted the WNA. “Design certification, construction and operation [license] costs are not necessarily less than for large reactors, placing a major burden on developers and proponents,” it said.

Over the last decade, the nuclear power sector is also facing a significant disruption as power consumption patterns shift. As more distributed energy resources (DERs) are added to the grid, they have empowered end-users to produce energy locally—signifying a break away from a historic top-down supply structure, and forcing many large and medium-sized baseload power generators to seek flexible operations. The proliferation of physical threats—both natural and manmade—and cybersecurity concerns are also afflicting larger grids, prompting concerns about resiliency and reliability.

For these reasons, and to ensure market viability, nuclear technology vendors are pouring time and funding to development of very small reactor designs of 10 MW or less. Some of the companies involved in projects follow.