Nuclear waste. Two words capable of sparking immediate fear.
But is there really anything to fear from the government's plan to build a disposal and storage facility for the nation's radioactive waste in South Australia?
What kind of waste will it hold and how potent is it?
How will the facility protect human and environmental health so far into the future that it's difficult to imagine what society will be like?
And why is it needed at all, given Australia produces a relatively small amount of waste from a single nuclear reactor that supports medical, research and industrial applications?
Tony Irwin is a lecturer in nuclear science at the Australian National University and used to manage the country's sole reactor in the Sydney suburb of Lucas Heights.
He came to Australia with years of experience in the nuclear industry overseas, including commissioning and operating eight power reactors in the UK, and helping Russian engineers improve the safety of theirs after the Chernobyl disaster.
He's very familiar with the waste Australia produces and believes the facility planned at Napandee on the Eyre Peninsula is a sound plan to manage it safely and responsibly.
"This is not a dump," Assoc Prof Irwin tells AAP. "It's an engineered facility. The word dump has this connotation that you just sort of throw it in a hole in the ground and forget about it.
"This is quite a sophisticated engineered facility we're talking about."
It's important to understand the dual roles Napandee will have, he adds.
First and foremost it will be a disposal facility - a final resting place - for thousands of barrels of what's called low-level waste. Typically it's items such as plastic, gloves, clothing, and filters that have small amounts of radioactivity.
This is material that will need to be managed for 300 years, Irwin says, at which point its radioactivity will have degraded to safe levels.
Because of its relatively low levels of radiation, it is safe to dispose of in near-surface, multi-barrier facilities - managed and monitored compounds that are slightly above or below ground level.
Napandee's second role will be a temporary storage site for intermediate-level waste - the reprocessed remains of spent nuclear fuel rods that powered Australia's first reactor before it was decommissioned and replaced at Lucas Heights.
Intermediate-level waste is much longer lived and must be stored at greater depths to isolate it from humans and the environment for thousands of years.
Australia has committed to developing a separate disposal option for intermediate-level waste but what form that will take won't be known for some time.
As an interim solution, the government intends to move intermediate-level waste held at Lucas Heights to South Australia.
At this stage, a possible option is bore-hole technology, which is being investigated by the CSIRO, and by the Australian Nuclear Science and Technology Organisation (ANSTO) that operates the Lucas Heights reactor.
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Broadly, it would involve drilling a deep hole at a yet-to-be determined location and lowering in individual canisters around 30cm diameter that contain the intermediate-level waste before sealing the hole.
Assoc Prof Irwin says it's commonsense and best practice to co-locate low-level radioactive waste of the kind that's currently held at about 100 sites across Australia at one purpose-built facility.
He says the vast majority of countries that produce radioactive waste already have facilities like the one proposed at Napandee, and Australia is behind the eight ball after an exhaustive and contentious 40-year battle to identify a site.
"It's the safest way to do it because it's then in an engineered facility, with multiple barriers, passive safety and it's properly monitored to international best practice," he says.
There is nothing unsafe about the current situation at Lucas Heights, where some 7000 drums of low-level waste are neatly stacked and stored in a building, Assoc Porf Irwin says.
Nor, he adds, is there anything unsafe about keeping intermediate level waste there.
But neither of those situations is a final solution, and there must be one, Irwin says.
David Osborn is the general manager for safety and technical matters at the Australian Radioactive Waste Agency, the government agency set up to establish the Napandee facility.
Detailed designs for the site are in development but an artist's impression exists, showing the structures that will house disposal vaults and a centre for curious visitors.
Mr Osborn says only waste that's appropriately packaged and conditioned, and satisfies strict acceptance criteria, will be taken in at the South Australian site.
He says low-level waste will be disposed of in rows of disposal cells - reinforced concrete vaults constructed at or partially below existing ground level, depending on engineering requirements.
Each cell will have a reinforced concrete base and sides, and will have a temporary roof over it while it's progressively filled.
"Once each vault is filled, it will be sealed off with a reinforced concrete lid, its temporary roof removed, and capped with a long-term engineered cover of earthworks," Mr Osborn says.
"This capping will comprise carefully designed mounds of geological material, impermeable membranes and soil, such that each vault will resemble a small hill. This will protect the vaults and help protect the environment."
Once the facility reaches "post-closure phase" there will be ongoing environmental monitoring, Mr Osborn says.
As for casks of intermediate-level waste, they'll be temporarily stored while a final disposal path is developed "for a different type of facility in a different location".
Currently there's only one in Australia. It's stored at Lucas Heights, and contains 20 tonnes of Australian nuclear waste that was sent to France for reprocessing and returned in 2015.
A second one that will be only partially filled with two tonnes of waste is due to arrive from the UK some time next year.
"The design of the intermediate-level waste storage facility will reflect strict licensing requirements, and it will retain access to the waste so that it can be moved to its final disposal site in the future," Mr Osborn says.
"As with the low-level waste, all intermediate level waste will be appropriately conditioned and packaged in accordance with strict waste acceptance criteria before being received at the facility."
Hefin Griffiths is the chief nuclear officer at ANTSO and says Australia is trying to satisfy the International Atomic Energy Agency (IAEA) - the nuclear watchdog of the United Nations.
"This meets the requirements of the IAEA in looking for a final disposal pathway rather than ongoing disparate storage," he says.
"And it allows the philosophy that the IAEA put in place which is that the generation that has benefited from nuclear science and technology should be the generation that actually finds that solution, rather than leaving it for future generations to manage."
He says that relatively speaking, low-level waste is easier to find a final pathway for given it only needs to be isolated for 300 years, vastly less than the thousands of years required for intermediate-level material.
Even so, 300 years is a long time. It's worth remembering that the first industrial evolution that transformed every aspect of human society began 260 years ago.
Mr Griffiths is confident there's enough shared knowledge out there to make sure Napandee can do its job, for low-level waste, for the amount of time required.
Beyond that, when time frames of thousands of years come into play for intermediate-level waste, things get a bit "dystopian".
"We don't know what society is going to be like," he says.
"You don't want somebody coming along and accidentally digging this material up at a time when they might not understand what the radioactive trefoil (symbol) means.
"Those are the sorts of considerations that are very long term and a bit dystopian. But we've got to ensure that the disposal options really account for a future that we can't predict."
And that's why the bore-hole idea being investigated by the CSIRO and ANSTO, using holes that could be up to two kilometres deep, is appealing.
Mr Griffiths says Australia, as a small-scale producer of radioactive waste, needs its own solution to long-life radioactive waste.
He says that if Australia pursued the kind of mined geological facilities used by nuclear powered countries that have vastly more, and more potent, waste to deal with, disposal costs for Australia's material would be astronomical.
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"If we were to replicate that model we would have by far and away the most expensive, per-unit disposal cost of waste, because our volumes are so small," Mr Griffiths says.
"So for us, a bore-hole disposal option still provides exactly the same multi-barrier approach, still relies on a geological barrier, but can be delivered in a way that is a lot more cost effective and in my opinion could be realised a lot quicker."
Australian Conservation Foundation campaigner Dave Sweeney accepts there is a need for final solution for all the radioactive waste the nation produces, but he has grave concerns about the current approach.
He says the federal government recently handed ANSTO tens of millions of dollars to expand storage options at Lucas Heights and there's no imperative to relocate waste from there any time soon.
He particularly objects to what he calls the unnecessary double handling of the worst nuclear waste Australia has.
"The plan is that a future federal government, sometime in the next 100 years, would relocate this material for deep burial at another currently undecided location via an undisclosed and unfunded process," he says.
He points to evidence given to a parliamentary committee last year by Carl-Magnus Larsson, CEO of Australia's nuclear regulator.
When asked why the majority of Australia's waste stored at Lucas Heights could not simply stay there, Dr Larsson replied: "There is no such thing as indefinite storage. That equals disposal."
"Waste can be safely stored at Lucas Heights for decades to come, but we need to talk long-term and even beyond the existence of ANSTO and the current facilities at ANSTO."
Mr Sweeney says there's never been a discussion in Australia that starts by asking "what's the best way to manage this material, or what is the full scope of ways that we could mange this material and which do we think is the least worst".
"We've heard that it can stay at Lucas Heights for decades to come. How about we use one of those decades to do what we've never done."
Earlier this week, traditional owners of the Napandee site launched Federal Court action to try to stop the waste facility from proceeding.
The Barngarla Determination Aboriginal Corporation has accused the government of excluding traditional owners from a community ballot that ultimately supported the facility.
- Australian Associated Press
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