Nuclear does not mean reliable power for Australia – by Peter Farley

In this, the first in an occasional series about nuclear power in Australia, Peter Farley says the claim of nuclear reliability is vastly overstated.

“No amount of experimentation can ever prove me right; a single experiment can prove me wrong,” – Albert Einstein.

As a student in the late 60’s I watched a training film which assured us that nuclear power was available every hour of every day and it would soon be ‘too cheap to meter’ (Chairman of US Atomic Energy Commission 1954).

In the seventies the nuclear story began to unravel – nuclear plants were nowhere near as reliable as claimed.

Nuclear plants must be shut down for maintenance and refuelling which takes 4-6 weeks every 1-3 years.

An additional complication is that due to the huge thermal mass and the risk of fuel containment failing with rapid operating changes, a nominal two-hour repair of a simple wiring fault requires a 48–72-hour power down/power up process.

Consequently, in the seventies and eighties nuclear availability was in the 70-80% range, not the claimed 95%.

Later it was realised that an emergency shutdown due to an external issue such as a turbine fault, loss of transmission etc., xenon gas was generated within the reactor and stopped the nuclear reaction.

Xenon, which itself is radioactive, must be carefully and thoroughly extracted from the reactor before restart.

After the Great Northeast blackout in the US in 1965 some reactors took two weeks to return to service.

Then it became clear that the benefits of a common design had their downsides.

In Canada in 1998 it was discovered that their design led to premature failure of cooling tubes, so 8 of 22 reactors were shut down. It took until 2006 for production to fully recover.

Then by 2014 a series of upgrades began with one to three reactors offline for 24-30 months each. 2023 output was still 16% down on 2014. France had a similar experience in 2020 and 2022.

The British Magnox reactors had problems with graphite blocks. There wasn’t a single year where nuclear output in the UK was above 86% of capacity.

In Switzerland in 2015 for a brief period all five reactors were off-line.

In Belgium in 2015, output was down 46% on the 2000-2012 average. Worse, for six weeks late in 2018, four of five reactors were offline and for the whole second half of 2018 nuclear output was 61% down on historical levels.

Fortunately for Belgium, they burned a lot of cheap gas. More significantly, they imported an average of 24% and up to 44% of their electricity for the half.

Before turning to the big producers, France and the US, let’s check the latest nuclear champion, Finland.

In winter 23/24 nuclear power ran faultlessly but load varies, so its contribution varied between 23% and 48% of the load.

But by March for long periods, imports were larger than nuclear power output. In May, nuclear output was 40% down on January.

While France is a nuclear success story, it is not without significant problems. Nuclear output peaked in France in 2005 at 450 TWh, 79% share of generation and 81% capacity factor.

By 2016-17 problems began to appear and nuclear output dropped below 400 TWh, then by 2020 around 350 TWh and 67.5% market share.

Then in 2022 disaster struck. A new form of stress corrosion was discovered in Civaux-1 which was only 20 years old.

Further, a record drought meant cooling water was restricted at another six reactors halving power output there, even after a temporary suspension of environmental regulations.

Soon half of France’s reactors were offline. The result was that in the midst of the global gas crisis, France’s 2022 nuclear output was 182 TWh below 2005.

That is the equivalent to 520 Snowy 2.0s. Relative to the NEM, the reduction is equivalent to quadrupling our 2022 gas output and completely draining seventy Snowy 2.0.

The NEM was in near crisis when coal output fell by 4.8% between winter 2021 and winter 2022. In July to September 2022 French nuclear output was down 43% from historical levels so instead of exporting 14% of its electricity for those months it imported 10%. Who will we import from?

While the US nuclear system is more productive with 93% Capacity Factor, it also has 870 GW of fossil fuels and hydro/pumped hydro and import capacity to back up the 97 GW of nuclear.

That is equivalent to increasing our existing coal, gas and hydro capacity by 50% to back up 7 GW of nuclear.

Alternatively, US nuclear power works because it only supplies 18% of US grid electricity from 91 reactors.

If we only want 20% of grid supply from nuclear, that means just four or five conventional reactors.

With 43 coal generators we still have problems when there are clusters of outages. If a large number of reactors is required so that the loss of three to five at once, as has happened in Belgium, Switzerland, Sweden, and Canada is not a problem, we need a number about where the US is now, meaning roughly a hundred 80-120 MW reactors.

But even then, it is no guarantee – in April 2023 nuclear output in the US was down 20% on January

In conclusion, a feasible number of nuclear reactors in Australia would not guarantee reliability, regardless of cost.

Peter Farley holds an engineering degree and is a manufacturing leader who built pioneering CNC machine tools for export winning many export and engineering awards. Peter has been studying the electricity sector since his 2012 Election to the Victorian Committee of Engineers Australia.

Picture: Peter Farley