SAFARI-1 uses exclusively LEU (low-enriched uranium) fuel, and more than 75% of all medical radioisotopes produced by SAFARI-1 and processed by NTP are made using LEU target plates.

The SAFARI-1 research reactor was originally designed to operate using what is known as highly enriched uranium or HEU. As international nuclear safety protocols and preferences have changed, HEU has gradually been removed as a reactor fuel – in order to reduce the risk of theft of HEU – and replaced with LEU or low-enriched uranium (uranium enrichment below 20%). In the mid-2000s, Necsa and NTP undertook this conversion process, from HEU to LEU, as encouraged by the Global Threat Reduction Initiative (GTRI) of the USA’s National Nuclear Security Administration (NNSA).

The core of SAFARI-1 has been fuelled using exclusively LEU since June 2009. This was accompanied by a staggered conversion of HEU target plates (from which radioisotopes such as Mo-99 and I-131 are extracted) to LEU. NTP’s first shipment of all-LEU-based isotopes, where both the fuel and target plates were made of LEU, was made to a customer in the US in late 2010, making South Africa the first country in the world to successfully implement commercial scale all-LEU Mo-99 and I-131 production.

Today, more than 75% of all isotope production at SAFARI-1 is made using LEU target plates, making NTP one of the leading suppliers of all-LEU Mo-99 and I-131 in the world.