Since 2005, Finland has been constructing the largest nuclear reactor in Europe alongside

a facility that could solve the problem of what to do with spent nuclear fuel.

When you think nuclear, the Nordic nation doesn't immediately jump to mind, but if

all of its planned projects come to fruition then, by the end of the decade, the country

will be second only to France in terms of the percentage of energy drawn from nuclear

systems.

After more than a decade of delays and cost overruns, 2022 will see the world's happiest

country switch on one of the planet's most advanced reactors, potentially kick-starting

a new age of nuclear power.

Finland actually has a long history with nuclear power. Its first reactor came online in 1977

and by 1980, three more were operational providing a third of Finland's total energy needs.

While these reactors are among the most efficient in the world – running at 95% capacity factor

for the past decade and continually being up-rated over their lifecycle – growing

demand and the seasonal fluctuations of other renewable sources like hydro and solar has

left the country relying on imports from Russia and Sweden to make up the balance of its energy

needs.

To lessen its reliance on foreign energy and to help meet its goal of carbon-neutrality

by 2035 the Finnish government approved the construction of what was meant to be the world's

first third-generation pressurised water reactor (ERP) at its Olkiluoto Nuclear Plant, known

as OL3, in 2005.

With an initial cost of USD $3.9BN, OL3 was to nearly double the plant's existing output

and provide 14% of Finland's energy needs when it became operational by 2010.

But while OL3 was the first EPR to begin construction - ahead of other next-generation reactors

in France, China and the UK - complexities surrounding the design, defects in safety

systems and contractual disputes led to over a decade of delays and in 2018 China's Taishan

1 became the first EPR reactor in the world to start operating.

Despite these delays and the cost swelling to over USD $10.25BN, OL3 was granted an operating

licence by Finland's Radiation and Nuclear Safety Authority (STUK) in 2019 - and in March

2021, 116 tonnes of uranium began to be loaded into the reactor ahead of its final testing

phase.

Once it's connected to the grid and the reactor begins commercial production in early

2022, the countdown will be on until OL3 begins adding to Finland's spent fuel stockpile.

Nuclear power is an incredibly clean way to produce energy, but it does create a by-product,

and it's the one problem we have yet to truly solve.

After 3-6 years, irradiated material is no longer able to sustain a reaction as a viable

fuel source and new material must be bought in to maintain the reactor's efficiency.

But while it's unable to generate electricity, spent fuel remains highly radioactive and

needs to be isolated for hundreds of thousands of years to prevent it from causing harm to

people or the surrounding environment.

Although spent fuel can be re-enriched and re-enter the fuel cycle the main way in

which we currently deal with radioactive waste is to simply store it in pools or sealed dry

storage facilities while it slowly decays.

While these methods keep spent fuel contained, it's not a viable long-term solution as

the system is heavily reliant on mechanical and human intervention and even under the

strictest conditions, it can be vulnerable to acts of terrorism or natural disasters

- the kind that led to the events at Fukushima in 2011.

With an estimated 250,000 tonnes of high-level waste already in storage around the world

and with no long-term strategy for dealing with it, many countries have chosen to completely

rule out nuclear power when it comes to meeting their growing energy needs.

In an attempt to solve this, since 2005, Posiva - a joint venture between Finland's two nuclear power

providers - has been constructing the world's first deep geological repository for spent

fuel in the billion-year-old bedrock not far from OL3.

Funded by charges collected from consumers through electricity sales, the USD $1BN project

that's due to complete in 2023 will see a series of tunnels extend half a kilometre

below ground creating a permanent disposal facility for spent fuel.

Now while burying nuclear waste might sound alarming and to cause concern to environmental groups,

the process at Onkalo is so much more than simply burying the problem.

Based on a Swedish disposal method known as KBS-3, irradiated material is placed into

boron steel canisters and enclosed within corrosion-resistant copper capsules before

being buried in individual holes and backfilled with bentonite clay - entombing it forever.

Once buried, no further mechanical or human intervention is required to contain the radioactive

payload, essentially eliminating one of the biggest barriers many countries have when

it comes to adopting nuclear power.

With the capacity to accommodate the last 50 years' worth of Finland's accumulated

spent fuel and the needs of its existing reactors until at least 2120 – at which time the

facility will be permanently sealed - Onlako appears to provide a viable long-term solution

to dealing with nuclear waste.

Described as a “game-changer” for the industry by the Director of the International

Atomic Energy Agency (IAEA), the lessons learned at Onkalo are being shared with other countries

and regions with suitable geological characteristics are being considered for similar disposal

sites.

Having seemingly solved the biggest drawback of nuclear power and with a sixth reactor

already planned to begin construction next year, Finland looks set to play a leading

role in the widespread adoption of nuclear technology as the world continues to transition

away from fossil fuels.

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