China’s Molten Salt Nuclear Reactors

China is completing a 2 megawatt molten salt reactor this month (August) and will start tests next month. Professor Yan Rui of the Shanghai Institute of Applied Physics, was a lead researcher on the TMSR (molten salt reactor). He wrote in a paper published in the Chinese journal Nuclear Techniques. The commercial reactor (100 MW due to be started in 2030) designed by Yan and his colleagues would be only 3 meters tall and 2.5 meters wide, but could produce enough electricity to power town of 100,000 inhabitants.

Weilong ZHOU,Rui YAN,Bo ZHOU. Radioactive product analysis of a small molten-salt reactor in primary loop[J].Nuclear Techniques, 2021, 44(7): 76-82

Based on the research of molten salt reactor (MSR), a conceptual design of small MSR core with thermal power of 100 MWt is proposed to meet the power supply demand of small area. By adjusting the initial fuel load of the reactor core, the reactor can operate at full power for 1 250 days without refueling, and then batch process fuel at the end of its life.

This study aims to analyze the yield and source of radionuclides in the main loop during such a small MSR operation by providing the constitutions, main components, and parameters according to the burnup characteristics and fuel salt characteristics of the long refueling cycle.

The calculation software KENOVI for three-dimensional Monte Carlo transportation program and burnup analysis module Origen-S were employed to analyze the fuel consumption analysis module, the storage of radioactive products in the main loop and the neutron energy spectrum and other neutron parameters.

The computation results show that the radioactivity at the end-of-life this small MSR is about 7.36×10^18 Bq, and the radioactivity of fission products in the end-of-life primary loop is about 5.89×1018 Bq, of which the inert gases, iodine isotopes and the volatile fission metal account for 7.35×10^17 Bq, 9.56×10^17 Bq, 8.17×1017 Bq respectively. The total radioactivity of actinide nuclides is about 1.47×10^18 Bq, of which the 239Np accounts for 98%.

This study provides a reference for radiation protection design and fuel reprocessing scheme of molten salt reactor.

Nextbigfuture had coverage last month on global molten salt and thorium reactor work.

SINAP aims for a 2 MWt pilot plant (TMSR-LF1) initially, then a 10 MWt experimental reactor (TMSR-LF2) by 2025, and a 100 MWt demonstration plant (TMSR-LF3) with full electrometallurgical reprocessing by about 2035, followed by 1 a GW demonstration plant. The TMSR-LF timeline is about ten years behind the SF one.

A TMSFR-LF fast reactor optimized for burning minor actinides is to follow.

The TMSR-SF0 is one-third scale and has a 370 kW electric heat source with FLiNaK primary coolant at 650°C and FLiNaK secondary coolant.

The 10 MWt TMSR-SF1 has 17% enriched TRISO fuel in 60mm pebbles, similar to HTR-PM fuel, and coolant at 630°C and low pressure. Primary coolant is FLiBe (with 99.99% Li-7) and secondary coolant is FLiNaK. Core height is 3 m, diameter 2.85 m, in a 7.8 m high and 3 m diameter pressure vessel. Residual heat removal is passive, by cavity cooling. A 20-year operating life was envisaged but the project is discontinued.

The 2 MWt TMSR-LF1 is under construction at Wu Wei in Gansu in a $3.3 billion program. It will use fuel enriched to under 20% U-235, have a thorium inventory of about 50 kg and a conversion ratio of about 0.1. FLiBe with 99.95% Li-7 would be used, and fuel as UF4. The project would start on a batch basis with some online refueling and removal of gaseous fission products, but discharging all fuel salt after 5-8 years for reprocessing and separation of fission products and minor actinides for storage. It would proceed to a continuous process of recycling salt, uranium and thorium, with online separation of fission products and minor actinides. It would work up from about 20% thorium fission to about 80%.

Beyond these, a 373 MWt/168 MWe liquid-fuel MSR small modular reactor is planned, with supercritical CO2 cycle in a tertiary loop at 23 MPa using Brayton cycle, after a radioactive isolation secondary loop. Various applications, as well as electricity generation, are envisaged. It would be loaded with 15.7 tonnes of thorium and 2.1 tonnes of uranium (19.75% enriched), with one kilogram of uranium added daily, and have 330 GWd/t burn-up with 30% of energy from thorium. Online refueling would enable eight years of operation before shutdown, with the graphite moderator needing attention.

There was a 2019 presentation on the SINAP molten salt project and the long-term plans through 2050 for China’s molten salt reactors. They would be six times more efficient with nuclear fuel, would need no water cooling and would be able to desalinate seawater.

32 thoughts on “China’s Molten Salt Nuclear Reactors”

  1. Ah, finally a bit more detail on the dry cooling setup. Looks like a direct secondary loop salt coolant to air heat exchanger, at least initially, with some consideration for using buffering tiertiary loops for supplying downstream services. Brayton supercritical Co2 seems like a good design philosophy for the power cycle but air brayton isn't horrific, since it could use COTS gas turbine powerplant hardware as is. Though the FLiNaK secondary loop to air heat exchange does give a little pause…

  2. We don't mind, the US has very safe nuclear energy, they will license small modular reactors such as NuScale,an IMSR fromTerrestrial Energy,as well as fast reactors from Bill Gates TerraPower.
    Canada has the best nuclear regulation. they are based on safety while US is based on rules.

  3. Quite a few do,BillGates has developed the Natrium system,and billionaires are behind OKLO,as well as General Fusion,NuScale is backed by a big engineering company with investors from diverse sources.

  4. China, obviously, doesn't have that issue. Molten salt reactors won't be adopted here in the US until we solve that problem ourselves.

  5. Every single MSR sited anywhere will require it's own individual permission in the west just like a big LWR, which will then be fought and appealed and end up taking upwards of a decade to recieve; while the applicant is forced to pay all the cost of having their application reviewed, re-reviewed and re-re-reviewed. There is a "bootleggers and baptists"-alliance of degrowth-greentards and fossil fuel interests which will oppose any and all simplification of the rules for small modular reactors.

    The cost of a regular LWR has very little to do with the fuel. The "golden goose" is at best a "golden quail".

  6. Molten salt reactors work at low pressures and would not release a lot of volatile compounds. They are in principle safer than water reactors. And they are already very safe.

  7. "There are better approaches with a much better risk/reward outcome."
    What did you have in mind?
    I am surprised that they don't try to build a Chloride salt fast reactors they seem to be simpler and don't need a graphite moderator, with spent nuclear fuel piling up in China and in many countries they would have lots of fuel available and also get paid for taking it of other countries.

  8. I want them to succeed. Then we can steal technology from China for a change…

    Also, did anyone else notice the placement of the reactor? 1200 miles away from the population centers along the eastern seaboard? That way if things blow up, only poor 'ole Mongolia gets hit with the radioactive cloud…

  9. Except that you're dealing with one of those people who still take the car to a garage to replace the filter.

    Even small scale, continuous, reprocessing of nuclear fuel sparks all the same regulatory restrictions that makes the large scale core changes so expensive.

  10. The technical, safety/licensing, and operational issues associated with the approach are significant and that equates to expensive. The touted benefits remain uncertain in terms of competitiveness.
    Fundamentally, is the investment really viable relative to the risks/problems that must be overcome?
    I think the fundamental are too uncertain to financially justify pursuing using a liquid fuel reactor. There are better approaches with a much better risk/reward outcome. However, the Chinese are certainly free to explore moving the approach forward.

  11. I wish more governments would spend money competing with every short sighted small business owners in every market that matters. We can't all get what we want.

  12. Mostly this is a test reactor to validate components and to do testing with radioactive salts that have trans Uranic elements.

    It validates metallurgy, pumps, heat removal, etc in preparation to making a larger reactor.

  13. You know, this is kind of a deliberate design choice for MSRs: Instead of waiting until the fuel is unusably contaminated with neutron poisons, (Isotopes which absorb neutrons without contributing to the chain reaction.) you continuously reprocess a bit of it at a time, maintaining good fuel quality.

    They're just proposing to batch process here as a testing procedure, a production reactor would just have a side loop continuously reprocessing a small portion of the fuel.

    Like continuously running your engine oil through a filter, instead of waiting until it turns to sludge and having a garage tear down your engine and clean it.

  14. It's a good thing that Brian blocked all the people that criticize msrs. So here you have an experiment in China where they're going to batch reprocess the fuel after 250 days and they say they're going to scale that up by 2030 like every other dream.

  15. Mars certainly had the water, I'm not so sure about the chemistry. I think we'll actually have to start digging around to be sure.

  16. Mars has a relatively low thorium concentration, and uranium is lower by about a factor of 3. Neither are in minable concentrations. For that you need water and chemistry to concentrate it in places, like we have on Earth.

  17. NASA is in fact working on "surface nuclear power" for space missions. The initial version will be up to 10 kW electric + 30 kW thermal. The units are modular, so if you need more power, just bring more of them. The thermal power is handy for things like keeping warm during the lunar night, or melting ice from one of the polar craters.

  18. When I was born, the Air Force was trying to develop a Molten Salt reactor for an atomic powered bomber. That was a long time ago.

  19. It is a different business model. Uranium reactors were like the old Kodak cameras where you had to buy Kodak film forever. Govt controls pretty much locked anyone else out from cutting your costs. So, you had a revenue stream forever.

    Molten Salt reactors use bulk chemicals. You can buy those from the cheapest quality producer. There is no golden goose to keep laying eggs.

  20. This is one of those areas where governments don't let you compete with them. Something to do with not wanting private companies to have nuclear arsenals, or some such bs.

    You'd think that Mars would have untapped fissile ores aplenty, but there's some concern that our ore beds only formed as a consequence of having had an oxidizing atmosphere, which Mars might not have had at the right period in planetary development.

    It will be interesting to see how Martian geology differs from Earth's in that regard. Who knows, maybe you still get usable hydrothermal ores under Martian conditions, only different ones?

  21. Governments don't like competition. Governments have decided that when it comes to nuclear energy nothing gets done anywhere without their detailed approval on every detail.

  22. Initial impression sounds like China is advancing on US nuclear tech re commercialization of new plants, but a shitload of nuclear waste on turnover/EOL ( (which is sooner than traditional plants?)

  23. I wish more bored Billionaires would spend money competing with governments on MSRs.

    Rockets are cool and all. But they'll need something to power the Mars base, right?


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