Radioactive waste: Technology makes waste storage safer

Queensland University of Technology (QUT) researchers have developed new technology capable of removing radioactive material from contaminated water and aiding clean-up efforts following nuclear disasters.

The innovation could also solve the problem of how to clean up millions of tonnes of water contaminated by dangerous radioactive material and safely store the concentrated waste.

Professor Huai-Yong Zhu from QUT Chemistry said the world-first intelligent absorbent, which uses titanate nanofibre and nanotube technology, differed from current clean-up methods, such as layered clays and zeolites, because it could efficiently lock in deadly radioactive material from contaminated water.

The used absorbents can then be safely disposed without the risk of leakage, even if the material became wet.

“One gram of the nanofibres can effectively purify at least one tonne of polluted water,” Professor Zhu said.

“This saves large amounts of dangerous water needing to be stored somewhere and also prevents the risk of contaminated products leaking into the soil.”

The technology, which was developed in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and Pennsylvania State University in America, works by running the contaminated water through the fine nanotubes and fibres, which trap the radioactive Cesium (Cs+) ions through a structural change.

“Every year we hear of at least one nuclear accident. Not only is there a risk of contamination where human error is concerned, but there is also a risk from natural disasters such as what we saw in Japan this year,” he said.

Professor Zhu and his research team believed the technology would also benefit industries as diverse as mining and medicine.

By adding silver oxide nanocrystals to the outer surface, the nanostructures are able to capture and immobilise radioactive iodine (I-) ions used in treatments for thyroid cancer, in probes and markers for medical diagnosis, as well as found in leaks of nuclear accidents.

“It is our view that just taking the radioactive material in the adsorbents isn’t good enough. We should make it safe before disposing it,” he said.

“The same goes for Australian sites where we mine nuclear products. We need a solution before we have a problem, rather than looking for fixes when it could be too late.”

With a growing need to find alternatives to meet global energy needs, Professor Zhu said now was the time to put safeguards in place.

ESA: Green’ satellite fuel designed to make space safer

On the day running up to launch when a spacecraft is fuelled, ground personnel look more like astronauts than engineers, putting on spacesuit-like protective gear.

This is an essential precaution when dealing with the current hydrazine fuel, but a new development could make satellite fuelling no more dangerous than filling up a car.

First used in rocket engines by the German Luftwaffe during World War Two, hydrazine remains the main propellant of choice for a satellite’s onboard thrusters, used for orbit correction or stationkeeping during its working life.

It is a high-performing storable propellant that is also ‘hypergolic’ – meaning it ignites spontaneously on contact with oxidiser or by itself with a catalyst, which makes a spacecraft designer’s job a lot easier.

Unfortunately hydrazine is also highly corrosive and extremely toxic. When leaked into the environment, it degrades in a few days but has the potential to harm plants and marine life, while exposure is considered harmful to people at just 50 parts per million.

Seeking an alternative, ESA has been working with a Swedish company called ECAPS, part of the Swedish Space Corporation Group, to build and test a thruster that runs on a safer, more environmentally friendly fuel.

ECAPS informs us that the development of High Performance Green Propulsion (HPGP) was initiated with the goal of meeting the requirements for future satellite missions. After more than 10 years of R&D, the HPGP technology is emerging as an enabling technology for improved performance, enhanced volumetric efficiency, reduction of propellant handling hazards and safer launch operations.

The HPGP technology developed by ECAPS, includes a storable monopropellant blend based on Ammonium DiNitramide (ADN) and thrusters with high-temperature resistant thrust chamber and catalyst.

For more information you can download ECAPS HPGP brochure here