700 nuclear engineers in China made good progress on detailed Molten salt nuclear reactor designs

Oak Ridge National Labs had a Workshop on Molten Salt Reactor Technologies. It was held on the 50th anniversary of the startup of the Molten Salt Reactor Experiment.

Molten-salt reactors use liquid, rather than solid fuel rods, as the fuel to produce the nuclear reactions that heat water to make steam and, in turn, electricity. They have several advantages over conventional light-water reactors in terms of safety, anti-proliferation, and economics, and are enjoying a renaissance as the world searches for sources of low-cost, low-carbon energy.

The workshop included presentations from reactor developers including TerraPower, Flibe Energy, Moltex Energy, and Terrestrial Energy.

Xu Hongjie, the director of the molten-salt reactor program at the Shanghai Institute of Applied Physics also presented. The Chinese Academy of Sciences, SINAP is collaborating with Oak Ridge to advance research on both salt-cooled reactors (which use molten salts to transfer heat and to cool the reactor) and salt-fueled reactors (in which the fuel, where the energy-producing nuclear reactions occur, is dissolved within the salt coolant.

Xu outlined a roadmap that shows that China is further along than any other advanced reactor R and D program in the world. China, which still gets nearly three-quarters of its electricity from burning coal, is racing to develop low-carbon energy sources, including both conventional nuclear plants and advanced systems such as molten-salt reactors.

Xu detailed a multi-stage plan to build demonstration reactors in the next five years and deploy them commercially beginning around 2030. The institute plans to build a 10-megawatt prototype reactor, using solid fuel, by 2020, along with a two-megawatt liquid-fuel machine that will demonstrate the thorium-uranium fuel cycle. (Thorium, which is not fissile, is converted inside a reactor into a fissile isotope of uranium that produces energy and sustains the nuclear reaction.)

In all, there are 700 nuclear engineers working on the molten-salt reactor at SINAP, Xu said, a number that dwarfs other advanced-reactor research programs around the world. The team has a preliminary design for a 10-megawatt thorium-based molten-salt reactor, and has mastered some of the technical challenges involved in building and running such reactors, such as the preparation of high-purity molten salts and the control of tritium, a dangerous isotope of hydrogen that can be used in the making of nuclear weapons. Limiting the production of tritium is a key research goal for the development of molten-salt reactors.

Most of the audience at Oak Ridge was familiar with the outlines of the Chinese program, the level of sophistication and the progress to date were startling to many listeners.

“It’s very surprising how far they’ve come in four years,” said John Kutsch, the vice president for business development at Terrestrial Energy, which is developing its own version of a molten-salt reactor. “That shows you what throwing hundreds of researchers at a project will do to speed progress.”

This is a slide from a prior presentation