TRISO Particles: The Most Robust Nuclear Fuel on Earth (2024)

FAQs

What are the particles in TRISO fuel? ›

TRISO particles have a fuel kernel made up of uranium dioxide or uranium oxycarbide that is then coated with four layers. Each particle acts as its own containment system thanks to its coated layers. This allows them to retain fission products under all reactor conditions.

As a participant in the U.S. Office of Nuclear Energy's Next Generation Nuclear Plant (NGNP) program for more than 15 years, BWXT has developed the expertise to manufacture TRi-structural ISOtropic (TRISO) coated kernels for this unique application.

The TRISO-coated particle is a spherical, layered composite. The layers that comprise a TRISO particle are the kernel, buffer, inner pyrolytic carbon (IPyC), SiC, and outer pyrolytic carbon (OPyC).

Tristructural isotropic (TRISO)-coated particle fuel is foundational for many high-temperature reactor (HTR) designs, including high-temperature gas-cooled reactors (HTGRs) and fluoride salt-cooled high-temperature reactors (FHRs).

TRISO + SiC Matrix. Fully Ceramic Microencapsulated (FCM®) Fuel is a new approach to inherent reactor safety by providing an ultimately safe fuel.

TRISO-X fuel is crucial in ensuring the safety and reliability of advanced nuclear reactors. Its ability to withstand high temperatures without melting provides safety benefits and contributes to the overall performance of the reactor.

Since low-activity graphite is generated in huge amounts, it is important to separate the high-activity fuel from moderate-activity graphite in the context of the volume reduction of the waste from HTGR. Then, the separated TRISO fuel could be reprocessed or be destined for disposal in a deep geological repository.

TRISO fuel particles were originally developed in the United Kingdom as part of the Dragon reactor project. The inclusion of the SiC as diffusion barrier was first suggested by D. T. Livey. The first nuclear reactor to use TRISO fuels was the Dragon reactor and the first powerplant was the THTR-300.

The TRIGA reactor uses uranium zirconium hydride (UZrH) fuel, which has a large, prompt negative fuel temperature coefficient of reactivity, meaning that as the temperature of the core increases, the reactivity rapidly decreases.

Nuclear power plants primarily use a specific type of uranium (U-235) for nuclear fission because its atoms are easily split apart. Although uranium is about 100 times more common than silver, U-235 is relatively rare, at just over 0.7% of natural uranium.

Who makes the most nuclear reactors? ›

Nuclear power plants operate in 32 countries and generate about a tenth of the world's electricity. Most are in Europe, North America and East Asia. The United States is the largest producer of nuclear power, while France has the largest share of electricity generated by nuclear power, at about 70%.

TRISO fuel particle design, as it manifests today, consists of an inner fuel bearing kernel surrounded by four ceramic coating layers, all of which are produced via fluidized-bed chemical vapor deposition (FBCVD).

Chernobyl fuel particles were essentially high burn-up uranium oxide fuel with a composition similar to that of the fuel in the reactor core but with some depletion of the radioisotopes of the more volatile chemical elements Iodine, Ruthenium and Caesium. Some particles were spherical, others were angular shards [2-4].

Used nuclear fuel is a complex mixture of the fission products, uranium, plutonium, and the transplutonium metals. In fuel which has been used at high temperature in power reactors it is common for the fuel to be heterogeneous; often the fuel will contain nanoparticles of platinum group metals such as palladium.