Quick questions on ANSTO OPAL research reactor: HSC Investigating Science Module 6

OPAL is a 20 MW reactor that uses low-enriched uranium fuel (less than 20 per cent U-235, well below weapons-grade) cooled by light water. It replaced the older HIFAR reactor in 2007 and is one of about 50 research reactors operating worldwide. Importantly, OPAL is not a power reactor: it does not generate electricity. Its purpose is to produce neutrons.

Neutrons are neutral subatomic particles produced in the reactor's core. Two main uses:

OPAL is the only Australian source of medical radioisotopes.

Silicon transmutation doping. Pure silicon ingots are irradiated to convert a small fraction to phosphorus, producing semiconductor-grade silicon used in high-voltage electronics for solar arrays and electric vehicles. OPAL is one of the world's largest commercial doping services.

About 700 visiting scientists from Australian and international universities use OPAL's beam instruments each year. Output includes:

:::worked Worked example Why can't OPAL's medical isotopes be replaced by chemistry?

Pure silicon ingots are irradiated to convert a small fraction to phosphorus, producing semiconductor-grade silicon used in high-voltage electronics for solar arrays and electric vehicles. OPAL is one of the world's largest commercial doping services.

Trace elements can be detected at parts-per-billion sensitivity by activating samples and measuring the gamma rays emitted. Used for forensic science, archaeology and environmental monitoring.

Researchers have used OPAL's neutron techniques to study Aboriginal ochre samples and stone tools, identifying trade routes and pigment sources across the continent.

CT uses X-rays for structural imaging; nuclear medicine uses radioisotopes for functional imaging.

ANSTO is a federal government statutory authority. Its work is publicly funded and regulated.

Neutron beam research is just as important as isotope production for the case study. :::