A Closer Look at Two Operational Small Modular Reactor Designs

There are literally dozens of small modular reactor (SMR) and microreactor designs being developed by different companies around the world, and some of the work has been going on for decades. Yet, only two designs have actually been built and put into commercial operation. POWER takes a closer look at both of them.

Power, by Aaron Larson 1 May 24

Many nuclear power supporters have long thought small modular reactors (SMRs) would revolutionize the industry. Advocates expect SMRs to shorten construction schedules and bring costs down through modularization and factory construction. They often cite numerous other benefits that make SMRs seem like no-brainers, and yet, only two SMR designs have ever been built and placed in commercial operation.

The International Atomic Energy Agency (IAEA) publishes booklets biennially on the status of SMR technology. In the IAEA’s most recent booklet, it notes 25 land-based water-cooled SMRs and another eight marine-based water-cooled designs are under development globally. It also lists 17 high-temperature gas-cooled SMRs, eight liquid-metal-cooled fast-neutron-spectrum SMRs, 13 molten-salt SMRs, and 12 microreactors. If you do the math, that’s 83 SMR designs under development, but only the KLT-40S and HTR-PM are actually operational.

KLT-40S

The KLT-40S is a pressurized water reactor (PWR) that was developed in Russia. It is an advanced version of the KLT-40 reactor, which has been used in nuclear-powered icebreakers. The first KLT-40S units, and, to date, the only two of these units to enter commercial operation, were deployed in the Akademik Lomonosov—the world’s first purpose-built floating nuclear power plant (FNPP, Figure 1 on original).

Main Design Features.………………………………………………………………………………………………………….

Deployment Details.…………………………….

Construction and testing of the FPU was completed in 2017 at the Baltic shipyard. In May 2018, the vessel was towed 4,000 kilometers (km), around Finland and Sweden, to Murmansk, completing the first leg of its journey to Pevek. Fuel loading was completed in Murmansk in October 2018. First criticality was achieved in November 2018, then in August 2019, the vessel embarked on the second leg of its journey—a distance of 4,700 km—towed by two tugboats to the Arctic port town of Pevek, where it was connected to the grid on Dec. 19, 2019. Akademik Lomonosov was fully commissioned on May 22, 2020, and it currently provides heat to the town of Pevek and supplies electricity to the regional Chaun-Bilibino power system.

HTR-PM

On Dec. 6, 2023, China National Nuclear Corp. announced it had commenced commercial operation of the high-temperature gas-cooled modular pebble bed (HTR-PM) reactor demonstrator. The HTR-PM project was constructed at a site in Rongcheng, Shandong Province, roughly midway between Beijing and Shanghai in eastern China…………………………………

Main Design Features.…………………………………………………………………………………………………..

Deployment Details.……………………………………………………………………. The civil work for the nuclear island buildings was completed in 2016 with the first of two reactor pressure vessels installed in March that year. The fuel plant reached its expected production capacity in 2017. Startup commissioning and testing of the primary circuit were finished by the end of 2020. The HTR-PM achieved first criticality in September 2021, and was ultimately grid connected on Dec. 20, 2021.

Spotty Results at Best

While it is laudable that these SMRs—the KLT-40S and HTR-PM—have been placed in commercial operation, their performance since entering service has come under fire. In The World Nuclear Industry Status Report 2023 (WNISR), a Mycle Schneider Consulting Project, co-funded by the German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety, and Consumer Protection, it says both designs have operated at low capacity factors recently.

Concerning the Chinese HTR-PM, the WNISR says, “Between January and December 2022, the reactors operated for only 27 hours out of a possible maximum of 8,760 hours. In the subsequent three months, they seem to have operated at a load factor of around 10 percent.” The Russian units’ performance has been nearly as dismal. “The operating records of the two KLT-40S reactors have been quite poor. According to the IAEA’s PRIS [Power Reactor Information System] database, the two reactors had load factors of just 26.4 and 30.5 percent respectively in 2022, and lifetime load factors of just 34 and 22.4 percent. The reasons for the mediocre power-generation performance remain unclear,” the report says.

Meanwhile, the promises of shortened timelines and lower costs were not borne out by these projects. “The experience so far in constructing these two SMRs as well as estimates for reactor designs like NuScale’s SMR show that these designs are also subject to the historical pattern of cost escalations and time overruns. Those cost escalations do make it even less likely that SMRs will become commercialized, as the collapse of the Carbon Free Power Project involving NuScale reactors in the United States illustrated,” the WNISR says………….. https://www.powermag.com/a-closer-look-at-two-operational-small-modular-reactor-designs/

May 4, 2024 - Posted by Christina Macpherson | China, Russia, Small Modular Nuclear Reactors