Corrosion Problem Shutters Half of France’s Nuclear Reactors

Just when France, and the rest of Europe, needed the country’s 56 nuclear reactors to be pumping out electricity at maximum power to counter the shortfall of energy supplies caused by the war in Ukraine, half of them have had to shut down.

An unexpected corrosion problem on pipes vital to the safety of one reactor discovered in January has led to a series of inspections that have so far closed 12 reactors for further investigation or repair.

The fault seems common to a whole series of France’s reactors. The shutdowns affect four of the largest N4 reactors of 1,500 megawatts, five 1,300-MW, reactors of similar design, and three 900-MW units. This, on top of a series of outages at 18 other reactors for repairs, updating, or regular safety checks, has left France with the lowest nuclear output in decades.

Some of these routine outages had been delayed because of the COVID-19 crisis, so this summer was set aside for a catch-up program. And adding to the industry’s woes is a European heat wave. This has made some river water, which a number of the remaining operational reactors rely on for cooling, too warm to allow full output under environmental regulations designed to protect fish life. It has also boosted demand for power to run air conditioning.

Bernard Doroszczuk, President of France’s Autorité de Sûreté Nucléaire (ASN), told a parliamentary hearing that the “discovery of unexpected stress corrosion” was the cause of the problem. Because of the discovery of the corrosion on one reactor and the subsequent inspection of more than 100 welds on others, he said he was confident the reactors were being made safe, but would have to stay shut offline until they were repaired. That work could take several years to complete.

Rather surprisingly, the stress corrosion seems to be as much a design fault as one of ageing: France’s older reactors which are edging towards retirement seem unaffected, and it is the newer, larger reactors that are in trouble.

This has meant France, which normally relies on nuclear for 70% of its electricity—currently down to 59%—is importing power from other European countries rather than exporting it as is normally the case. This may be costing the state-controlled EDF Group’s finances as much as €18 billion (US$19 billion) in lost revenue.

This is a blow to a company already €43 billion ($45 billion) in debt and needing to spend billions more in repairing reactors before it can get more revenue. It means the company may need massive state intervention to keep it afloat. Compounding the problem is an aging work force, with many of the technical experts who’ve maintained France’s 1980s nuclear fleet reaching retirement.

“There’s a whole series of problems that have led to an absolutely unprecedented level of difficulties and shutdowns in France’s nuclear industry,” said Yves Marignac, a nuclear energy specialist at think tank négaWatt.

The corrosion issues capped a 10-year decline in the performance of the nuclear fleet, he said.

EDF’s woes could have a knock-on effect on the UK’s nuclear ambitions. The company, in partnership with the Chinese, is building two 1,300 mw reactors at Hinkley Point in Somerset. They’re due to come on line in 2027, already over budget and years late. The company is anxiously awaiting UK government approval, due in July, to build two more reactors in south east England at Sizewell in Essex.

The company accepts it does not have the money to finance that project and the UK government has passed special legislation to allow a surcharge on electricity bills to pay for the construction, a subsidy dubbed a nuclear tax by opponents. It is likely to be unpopular at a time of soaring energy bills.

The problems of financing the UK’s nuclear ambitions and how EDF will resolve its reactor corrosion and ever-increasing debt problems are clearly now for the governments of Britain and France to resolve. It is tricky politically, coming at the same time Europe faces soaring energy prices and a winter supply crisis caused by the war in Ukraine and Russia’s stranglehold on gas supplies.

Comments 1

Edouard Prisse says:
8 months ago
The French nuclear reactor rust problem amounts to sloppy oversight at the time of construction of the more recent reactors in France. As repair will take two to three years, the consequence is huge. If sloppiness is at all to be elimiated from habit when constsruction continues, France now needs the men that were bosses and under-bosses at the time of construction to be puniushed severely. And better punish one too many than one too little. This is totally anacceptable, not least as well for France’s reputation as a reliable builder of nuclear reactors. The punishments need to be known publicly and to reverberate.