This is a 3-part series written by Geni.Energy Director Virpi Barrett and Sunshine
Hydro CTO Chris Baker. You can read the previous parts for the facts behind the nuclear debate and about how nuclear fits into Australian renewable energy grid.
I've been gobsmacked by a glaring omission in the Australian nuclear discussion: storing highly radioactive nuclear waste.
The enormity of the challenge and the time scale is simply beyond human comprehension. Nuclear waste neutralises in 100,000 years.
Imagine if Neanderthals had left a legacy like that for us to guard.
While we've been happy to create this waste for over 60 years so far, the world's very first permanent repository Onkalo ("cavity" in Finnish) is only starting operations later this year.
As a Finn myself, I'm immensely proud of the global leadership my home country is taking to manage the risk.
However, we have to accept the reality: even if we successfully store the waste throughout our lifetime, and the life of our children and grandchildren, we are still only about 0.1% through the timeline.
Nuclear fuel and waste
While a nuclear fuel rod is safe to touch before use, once the reaction has started in a nuclear reactor, the radiation can’t be stopped and proximity to the used rods is fatal. The spent fuel slowly neutralises and becomes harmless, but the half-life can be up to 24,000 years.
This means half of the radioactivity has decayed after 24,000 years.
After the half-life has lapsed twice, a quarter of it is left, and so on.
The spent fuel is typically first stored in a deep pool within the nuclear power plant. The water acts as a radiation shield to keep employees safe. However, there are debates over the safety of these pools in case of incidents like earthquakes or terrorist attacks.
There are also storages to house all the contaminated rubbish created by a nuclear power plant over its lifetime – everything from replaced pumps to the rubber gloves that some-one wore inside the control zone of the nuclear power plant. These storages are typically underground.
Radiation and contamination control
I’ve seen this first-hand when I worked as a radiation controller on control zone borders of a nuclear power plant. Most of the year there was nothing much to do, but when the plant shut down for refuelling and maintenance, our team grew about six fold to manage the rush of hundreds of contractors working in three shifts.
We ensured no-one walked past the border without putting on or taking off their shoe covers – green, orange or red indicating the expected contamination level of each zone.
We measured the contamination level of every passing tool and rubbish bag, sending the active ones to be cleaned or stored underground.
Employees crossing the border also got measured and sent back to change clothes or to shower as needed.
We also monitored the radiation exposure to each employee and made sure that if their personal cumulative dosage got too high, they moved to working on something else, in less active areas.
To prevent high exposure to any staff member or contractor who had to carry out maintenance work in highly active areas, we sent out a team to build radiation shields made of lead to reduce the radiation level on their work site.
This naturally increased the exposure to the radiation protection team, but it was
necessary to keep everybody’s personal exposures below the limit.
Because you can’t see or feel radiation, everyone kept a beeping monitor in the chest pocket of their uniform.
It would make a sound every now and then, more frequently if the radiation
level was high. I distinctly remember the monitor screaming when I crawled inside a steamer, alerting me to hurry up and get away – as if the incredible residual heat and moisture weren't deterrent enough.
Permanent waste repositories
After news of the Kyshtym disaster at the Mayak nuclear fuel reprocessing plant in Soviet Union was made public, the Finnish parliament decided to ban the export of nuclear waste to ensure it didn't end up being used in nuclear weapons.
This led to a decision that the human generation which benefits from the nuclear power, must also deal with the permanent storage of the radioactive waste.
The Finnish government set a timeline for building the facilities and stipulated that they were built to last 100 000 years.
With this in mind, I find it almost amusing when people ask whether the cost of storing nuclear waste is fully included in the price of the nuclear electricity!
The permanent repository Onkalo (Finnish for 'cavity') is built 450 meters down into the bedrock.
Robot tractors will transfer the spent fuel rods that will be sealed in huge copper cylinders, packed in bentonite and entombed behind vast concrete plugs.
The repository is designed to last a million years, but the company operating the repository will seal it and hand it back to the state after 100 years.
However, the planning goes well beyond that.
The location of Onkalo was chosen for its boringly common geological make-up. There are no valuable minerals to be mined or even anything rare that might become valuable at some later
point in time - that might give reason for someone to disturb the site in the future.
The bedrock has been sitting still for 1,900 million years – so it’s certainly not an active earthquake region.
Not all countries with nuclear energy have such ideal locations.
Warning signs
Some people think the site should be left totally unmarked, while others think such sites should have warning signs. There is no international consensus on this, but the Finnish legislation goes as far as mandating that the information about the repository must be translated into 40 languages and kept up-to-date as information technologies develop.
Anyone who has salvaged the family videos from the VCR era or read original Shakespeare’s original text will have a feel for the speed of change in IT and language.
The markings may go beyond language though. There are proposals to use art as an expression of danger and despair, trying to instil the emotion not to enter.
The U.S. is considering a repository at Yucca Mountain in Nevada, with a proposal to plant genetically-modified yucca cacti turned cobalt blue across the entire Yucca Mountain site.
However, over thousands of years, we can expect the rise and demise of whole civilisations.
There may be calamities that wipe out large parts or all of humanity and who knows who – or what – survives or comes after, and what level of intellect and ability they may possess.
Regardless of that, radiation is likely to be dangerous to them.
There’s no denying we have taken a risk that is simply not ours to take.
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