Selecting the right structural materials for fusion reactors

Two promising structural materials are in contact with liquid metal fuel breeders. The answer has been found by researchers of Tokyo Institute of Technology, National Institute for Quantum Science and Technology, and Yokohama National University. The success of a fusion reactor design depends on the high-temperature compatibility of reactor structural materials with the liquid breeder.

Several potential designs are being explored for a fusion reactor that could be a powerful means of generating clean electricity. The fusion of two nuclei releases a lot of energy. This energy is trapped as heat in abreeding blanket, which is a liquid lithium alloy surrounding the reactor core. This heat is used to run a turbine. The closed fuel cycle created by theBB is an essential function of fusion fuel breeding.

The attractive function of producing hydrogen from water, which is a promising technology for realizing a carbon-neutral society, is served by the operation of aBB at extremely high temperatures. The fusion reaction can cause theBB to heat up to over 1173 K. The safety and stability of the reactor can be compromised by the risk of structural materials in contact with theBB becoming corroded. It is necessary to find structural materials that are compatible with theBB material at these temperatures.

The liquid metal is being explored. Liquid LiPb alloy is a promising candidate. There are some structural materials that are compatible with liquid LiPb that are being explored. There is no information on this compatibility beyond 973 K.

A team of scientists from Tokyo Tech, QST and YNU, Japan, led by Professor Masatoshi Kondo, have demonstrated compatibility at much higher temperatures. Their findings are published in a journal.

The team first synthesised high-purity LiPb by melting and mixing the Li and Pb in an apparatus. The alloy was heated to those temperatures and liquified. The samples were placed in the liquid LiPb for 250 hours. An interesting finding is that oxidation pre-treatment to form an Al 2 O 3 layer did not provide any resistance beyond 1023 K.

The cross-sections of the retrieved samples showed that CVD-SiC reacted with the LiPb alloy to form a layer of oxides, which provided it with resistance to oxidation. The oxide LiAlO 2 formed after the reaction with LiPb and acted as an anti-corrosion barrier. In the case of the pre-treated FeCrAl, the Al 2 O 3 surface layer provided resistance at 873 K but was transformed into LiAlO 2 at 1173 K.

More information: Masatoshi Kondo et al, Corrosion-resistant materials for liquid LiPb fusion blanket in elevated temperature operation, Corrosion Science (2021). DOI: 10.1016/j.corsci.2021.110070 Citation: Selecting the right structural materials for fusion reactors (2022, March 3) retrieved 3 March 2022 from https://phys.org/news/2022-03-materials-fusion-reactors.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.