High-Temperature Reactors for Green Hydrogen

Subject – Environment

Context –

Concept –

High temperature nuclear reactors (HTRs) represent a novel way to produce hydrogen at large scale with high efficiency and less carbon footprint.
High Temperature Reactor (HTR) technology has been developed from the late 1940s in US and Germany.
The present Very High Temperature Reactor (VHTR), operating at >7500 C, has over the years, evolved into a new reactor concept, designed to be a very efficient and safe system.
It is a helium-gas cooled, graphite-moderated, thermal neutron spectrum reactor, which can provide electricity and process heat for wide-ranging applications, including hydrogen production.
Hydrogen production through fossil fuels entails CO2 emissions. Therefore splitting of water to produce hydrogen is a better alternative.
There are several methods to extract hydrogen from water and two of the highly used processes are
- High Temperature Electrolysis (HTE) and
- Thermo-chemical cycles.

Both these processes require very high temperatures, which can be provided by the VHTRs.

Indian HTR

Indian HTR development programme has two elements:
- a 100 kW (thermal), 1,000 degrees C portable ‘compact high-temperature reactor’ (CHTR) for technology demonstration;
- a 600 MW (thermal), 1,000 degrees C ‘Indian high-temperature reactor hydrogen’, or IHTR-H.
These two reactors would be powered by ‘TRISO-coated particle’ fuel. TRISO — ‘tristructural isotropic’ — comprises uranium, carbon and oxygen, all of which India can make.
The IHTR-H is designed to produce about 7,000 kg of hydrogen, 18 MWhr (thermal) of energy per hour and 9 million litres of water a day.