Frequently asked
questions

Qark One is a thorium-fuelled reactor of about 300 MWe (920 MWth) that Qark Energy is designing for India. It is a pressure-tube design based on published data for the AHWR-300 LEU, developed by India’s Bhabha Atomic Research Centre (BARC).

Small modular reactors are usually defined as reactors of up to about 300 MWe whose major components can be made in factories. Qark One sits at the top of that range and is designed around components that Indian industry can fabricate.

Fuel sits in 452 vertical pressure tubes that pass through a tank of heavy water, which slows the neutrons. Ordinary water boils as it flows up through the tubes, and the steam–water mix rises to four steam drums. The steam goes to the turbine and the water falls back to the core. Gravity and the density difference keep this loop moving, so there are no primary pumps.

No. A fuelling machine on the reactor deck changes fuel from the top while the reactor keeps running.

Qark One is at concept stage. Our general-arrangement drawing, QE-GA-001 (rev A), sets out the reactor block, the core lattice and the principal data. It is indicative and not for construction.

Thorium is a naturally occurring metal, about three times as abundant as uranium in the Earth’s crust. Thorium-232 cannot sustain a chain reaction on its own, but when it absorbs a neutron it becomes, after a short decay chain, uranium-233, which can.

India holds one of the world’s largest thorium reserves, much of it in the monazite sands along its coast. Since the 1950s, India’s three-stage nuclear programme has aimed to make thorium its main fuel.

High-assay low-enriched uranium (HALEU) is uranium enriched to between 5 and 20 percent uranium-235. Because thorium cannot start a chain reaction by itself, Qark One mixes it with HALEU, which drives the reaction while the thorium breeds uranium-233 that is burned where it forms.

India follows a closed fuel cycle, in which spent fuel is reprocessed to recover useful material, and Qark One’s spent fuel would be managed within that national framework. A thorium fuel cycle also produces far less plutonium and other long-lived heavy elements than a uranium one.

Qark One is designed to stay safe without power, pumps or operators. Natural circulation keeps water moving through the core, and isolation condensers in a gravity-driven water pool of about 8,000 m³ carry decay heat away. The design gives a grace period of 72 hours with no operator action.

By either of two independent systems. SDS-1 drops shut-off rods into the core; SDS-2 injects a liquid neutron poison into the moderator. Each can shut the reactor down on its own.

The Atomic Energy Regulatory Board (AERB) regulates the safety of nuclear facilities in India. We plan to engage with it early, well before applying to build a first unit.

We have not announced a site. Retiring thermal power stations, industrial clusters and coastal sites are all good fits for Qark One, and we would like to hear from potential hosts.

Buy power or steam, partner with us on engineering and manufacturing, invest, or join the team. The contact page routes each of these to the right people.