Exclusive-EDF contractors relax radiation exposure limits to speed up reactor repairs

By Benjamin Mallet

PARIS (Reuters) – Some contractors helping French power giant EDF to inspect and repair its corrosion-hit nuclear reactors are planning to relax their rules on radiation exposure limits so that their workers can spend more time on the job, EDF told Reuters.

The company, which is rushing to get its fleet of nuclear powerstations ready for the winter, said the new threshold was in line with its own standards and remained well below French legal limits.

“We have been informed by some of our partners that they expect to increase the radiation exposure limit for some of their staff,” EDF said in emailed comments on Friday, responding to a Reuters query.

“The activities currently underway at our plants lead to a higher number of hours worked in the nuclear part of our sites. This additional activity had not been foreseen by our partners when they set their radiation limits,” the company said.

Two sources with direct knowledge of the repair works told Reuters that at least one EDF contractor, French company Monteiro, had already increased the maximum exposure its workers could be subject to, adding this posed no health risk.

A Monteiro spokeswoman had no immediate comment.

The sources said the changes to the safety guidance illustrated how EDF was racing against the clock to restart 15 reactors taken offline last winter after the emergence of stress corrosion at some plants.

A further 14 reactors are also off grid for regular maintenance and to save on fuel before the winter, meaning 54% of France’s nuclear fleet – the world’s biggest after the United States – is offline.

The unprecedented number of outages – which come as Europe scrambles to find alternative supplies to Russian gas – has worsened a continent-wide energy crunch and helped to push power prices to record highs.

French nuclear output is at a 30-year low. EDF said on Thursday it expected lower production to shave 29 billion euros off its 2022 core earnings — its fifth profit warning of the year.

The company has blamed a shortage of skilled professionals and radiation risks for a maintenance schedule that has left France, long Europe’s biggest electricity exporter, importing power from neighbours even before temperatures fall.

Workers checking and repairing the plants are required to operate in a part of the reactor where radiation is high, so they can only spend a limited amount of time in it, EDF Chief Executive Jean-Bernard Levy said last month.

EDF has said it expects to meet its schedule to restart the 29 reactors currently offline by Feb. 18, though some analysts say that is too optimistic.

Below legal limit

To help EDF stick to the schedule, Monteiro – which supplies welders to EDF – raised the annual radiation exposure limit for its workers to 14 millisievert from 12 previously, the two sources said. This was still comfortably below the French legal limit for workers in the nuclear sector of 20 millisievert, they added.

“We try to respect our principles and it is not because we are in a crisis that we are going to let people burn,” said one of the two sources, who both work in the nuclear industry.

Millisievert is a unit measuring the radiation dose accumulated over a certain period of time by an individual.

On top of Monteiro, Reuters contacted five other French contractors employed by EDF. Three of those did not reply to a request for comment, one declined to comment and one was not immediately available for comment.

An adviser to the energy ministry, who asked not to be named, said France’s agency for nuclear safety ASN acted in a “strictly independent manner” to ensure the protection of workers in the sector, adding that an exposure of 14 millisievert was the equivalent of two chest scans.

EDF said 14 millisievert was the existing maximum radiation exposure the company allowed for its staff and the reference for its contractors, although some had opted for lower limits.

One of the sources who spoke to Reuters said it was rare for EDF employees to reach an exposure level of more than 9 millisievert. EDF did not comment.

Below risky levels

According to the United Nations scientific committee on the effects of atomic radiation, exposure below 200 millisievert is considered weak and below 20 millisievert is very weak.

Klervi Leuraud, a radiation expert at the French institute for radio-protection and nuclear safety IRSN, said the threshold of 14 millisievert remained well beneath levels considered as posing a health risk.

One of the sources who spoke to Reuters said workers fixing the reactors operated in challenging conditions.

“People are working in a constrained area, repairing pipes that are 3 centimetres wide in sites that aren’t bigger than a Paris studio apartment. We try to make the job safe and finish the works on time but there are plenty of hazards,” the source said.

“Staff need to be rotated in and out and the problem is that this is an extremely specialised job, and the number of people with the required skills is limited.”

EDF has drafted in hundreds of specialised workers, including welders and pipe-fitters from six French contractors, U.S. nuclear plant maker Westinghouse Electric Company and another U.S. firm, the sources said.

One of the reasons for hiring Westinghouse is that it makes robots that carry out some of the welding and do not have radiation exposure limits, one of the sources said.

EDF also bought replacement pipes from neighbouring Italy. But the sources said that unexpected glitches — some of the pipes sent in by the Italian suppliers were of the wrong size – and complex quality-control procedures slow down the repairs.

Each pipe welding can take up to three days and hundreds of paperwork signings, they said. EDF told Reuters it was normal to have to re-adjust replacement components, as they never came in the right size.

Government ministers have publicly urged EDF to stick to its maintenance schedule. The utility forecasts enough reactors will come back online by December-January to guarantee nuclear production levels in line with last year.

However, one of the sources said expectations that weldings at EDF’s Civaux 1 reactor – one of EDF’s most powerful, with a capacity of 1,450 megawatts – be completed in the next six weeks “appear unrealistic”.

The source said only six weldings out of 30 had been completed so far at the reactor. A seventh welding completed this week was faulty and needs to be redone, the source said.

In its comments to Reuters, EDF said the maintenance and repairs schedule took into account current and future works: “As far as Civaux is concerned, the works are progressing according to plan.”

(Additional reporting by Elizabeth Pineau, Forrest Crellin and Matthieu Protard. Writing by Silvia Aloisi; Editing by Daniel Flynn)