Heather on her visit to OPAL. The steel cage that is intended to protect the reactor from aircraft impacts, is visible in the background.
Credit: Katynna Gill
I was trying to get to the heart of neutron science and that meant travelling to the site of Australia's newest and most technologically advanced nuclear research reactor. But like the tricks of a stage magician, I found that sometimes fission can be as hard to see as it is to understand.
Nuclear technology is firmly entrenched in intriguing controversy. But on my first visit to the reactor, I found myself drawn towards the mystery of fission for its own sake.
I'd spent weeks researching everything nuclear for a 16-page supplement in the latest print edition of Cosmos magazine, and now I was driving 50 km across Sydney in the rain and it was making me feel a little edgy. I was crossing the city from the northern suburbs to Lucas Heights, a comfortable scenic expanse in the far south, and home of the Australian Nuclear Science and Technology Organisation (ANSTO).
The visit – to tour ANSTO's new reactor, OPAL - felt a little like coming face to face with someone I'd met remotely over the Internet. The trip was the culmination of six weeks research into nuclear research reactors – what they did (create radioisotopes for diagnosing and treating cancer and components for semiconductors) and what they had the potential to do (understand the structure and nuances of an astounding range of materials in great detail).
Shiny silver pipes
Media interest was building about the opening of OPAL, the replacement of 1950s reactor HIFAR (High Flux Australian Reactor), described by some scientists as a Model T to OPAL's Porsche.
For the last six weeks I had eaten, slept and breathed nuclear science as I attempted to grasp for Cosmos how this A$360 million nuclear reactor worked, as well as everything associated with building a reactor in Australia.
I had many questions. How does the reactor - touted as one of the top three research reactors in the world - affect Australian science? Why are we making radioactive isotopes and carting them across the country? What does the world think of OPAL? And what are those several pieces of technology attached to shiny silver pipes which feed out of the nuclear reactor's core (such as the 'high-resolution powder diffractometer', or the 'thermal 3-axis spectrometer')?
More than anything, I was looking forward to seeing radiation. I'd discovered that once the magic of fission begins, the core is suffused in the eerie blue glow of Cherenkov radiation. This is a side-effect of charged particles passing through an insulator - in this case demineralised water - at speeds faster than the speed of light in that medium.
It sounds like science fiction, which is why I was looking forward to seeing it.
Kick-starting fission
Fission in a reactor core is kick-started by dropping a radioactive element into the core - a box full of aluminium-clad uranium 235 fuel rods - causing the uranium atoms to split and release neutrons. Neutrons are the mass-bearing, chargeless associates of protons within the atomic nucleus.
Once the neutrons are liberated they can be directed along the mirrored surfaces of long tubes called neutron guides. Here they are subjected to a range of adjustments, such as being cooled to about -250°C, being slowed, or being fed into 'neutron scattering' instruments.
These instruments were causing a buzz locally and internationally. I'd heard how they could be used to understand a whole range of questions, from building better hydrogen fuel cells to understanding protein interactions. These in turn, could redefine the way we understand disease pathogens such as the AIDS virus or the bacteria responsible for Legionnaire's disease and meningitis. I'd also heard neutron scattering techniques described as a "fast track" to Nobel Prize-winning science.
Lost at first sight
I arrived at the reactor site to find myself surrounded by a scene not unlike some of the more remote stretches of Tasmania. Stepping out into the heath-filled landscape I noticed tiny flowers and a cavalcade of insects. Surely there were endangered species thriving in this untouched island, marooned in the vastness of Sydney southern suburbia.
ANSTO describe the radiation produced by the reactor's airborne emissions as 0.004 milliseverts per year (recommended international safety standards are less than one millisevert annually). Whatever the dosage, I certainly wasn't getting any closer to the kind of radiation I was seeking here.
Entering the facility itself was a lot like visiting a maximum security prison, except that the staff is better dressed. Cameras and phones are kept in lockers at reception. There's also a lot of police around; the Australian Federal Police have a station at the site. Barring security, the site could also be compared to a well endowed university campus, with café, athletic centre (with a pool), and manicured grounds.
I met with ANSTO science communicator Katynna Gill and she let me down gently. Sadly, the core wasn't running at full power, so no blue glow.
Twinkle-eyed children
Despite this disappointment, I was keen to get as close to the core as possible and she was happy to comply. We then embarked on an in-depth tour of the reactor building, guide hall and offices, stopping only to play with the models outside the reactor building and various devices developed for school education.
Interacting with the community is a big interest of ANSTO and several times during the tour we threaded our way through groups of twinkle-eyed children and grandparents. Their guides, Gill explained, were often ex-staff members who would continue to be involved with the organisation by taking interested people around the site. School groups came daily, but I was surprised by just how many members of the public thought a trip to the reactor would be just the thing to do on a rainy Wednesday.
From the outside, the reactor building looks like a squat, geometrical modern mansion that some architect has decided would look great beneath a steel cage.
In fact, INVAP S.E., the Argentinean company that built the reactor, had a good reason for adding this feature. The building was commissioned in 2000 but work did not begin until after the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) issued a licence to construct the reactor in April 2002, seven months after U.S. airliners were hijacked and flown into buildings on September 11, 2001. The cage is intended to protect against a full-scale impact by aircraft.
Glimpse of the core
Finally inside, I toured the area in company with OPAL reactor manager Tony Irwin. The microwave-sized core is housed in a 14-metre-deep cylindrical pool of pure water, which acts to absorb neutrons escaping from fission.
Like the rain, circumstances were again against me, with work being carried out in the room directly surrounding the core. I could see the suited men in action through the window, but I couldn't get close enough to peer into the pool and see for myself the process that has the potential for everything from revolutionising medicine to generating energy.
Taking pity, Irwin introduced me to a camera viewing system that zooms into the deep reactor pool. I may have only seen de-mineralised water, or the paint on the concrete sides of the reactor pool, but finally I had my glimpse under the magician's table at the core of a nuclear reactor, sitting innocuously in a circular steel well that shed a faint blue light.
It wasn't even close to peering into the spectacular furnace of nuclear energy of an atomic bomb, nor was it like stepping firmly to one side of the nuclear debate. But coming close to the core of a nuclear reactor is still an experience engraved in my memory – even if, like an elusive comet or the feeling you get after Christmas, it didn't burn quite as brightly as I'd hoped.
Read the full story about OPAL in the April/May print issue of Cosmos available in stores now – or alternatively subscribe here.
Heather Catchpole is a Sydney-based science writer.
