Artère du Rhône: update on pipeline repairs

In 2025, two leaks occurred on the pipeline connecting Fos-sur-Mer (Bouches-du-Rhône) and Tersanne (Drôme), resulting in pipeline ruptures (in Saint-Martin-de-Crau on 13 June and in Saint-Rémy-de-Provence on 26 September).

Since then, NaTran has engaged its teams to ensure the pipeline is back in service by the end of August 2026, prioritising the safety of people, property and the environment in the vicinity of the pipeline.

In line with the procedure established with the authorities, NaTran:

• (i) Sent a smart pig through the pipeline using EMAT technology[1],
• and (ii) Will proceed, as required, with the scheduled repair operations based on the inspection results.

Restrictions on gas transit can only be lifted following this inspection using a smart pig and any related repair work, to ensure that operations can safely resume.

(i) Phase 1: pigging run on 200-km pipeline between Fos and St Avit

To prepare the pigging run, preliminary operations have been carried out since December 2025:

• the refurbishment of pipeline sections at Saint-Martin-de-Crau, Noves and Saint-Rémy-de-Provence, to guarantee pipeline continuity;
• the modification of the receiving station at Fos-sur-Mer, to enable the introduction of the pig into the pipeline;
• installation of a pre-expansion station at La Fossette (Bouches-du-Rhône) to ensure optimal pig running;
• pipeline cleaning operations prior to the pig running.

(ii) Phase 2: verification of inspection results and repairs if necessary

In mid-April, the quality of the data collected during the pig running was validated by NaTran’s service provider responsible for the pipeline inspection.  An in-depth analysis of this data is currently underway; it will define the nature and precise location of any repair work required to lift the restrictions on gas transit, scheduled by 31 August 2026.

To meet this timeline, NaTran is anticipating possible repair scenarios that may soon be carried out on the pipeline connecting Fos-sur-Mer to Tersanne, depending on the results.  Discussions are therefore underway with local residents and authorities concerned, survey teams are conducting field measurements, and steel pipes have been procured to be readily available if required.  Any potential repair work may last several months.
 

Simultaneously, investigations into the origin of these leaks are ongoing, conducted by NaTran and an independent expert, under the supervision of the relevant authorities.  While the final conclusions of these investigations remain pending, current assessments indicate that the cause is likely a particular form of stress corrosion cracking, arising from a combination of factors, including the pipeline’s material properties, the mechanical stresses involved and the specific conditions of its installation environment.

NaTran will incorporate the findings of these investigations into its industrial practices and implement appropriate measures across the rest of its network, particularly those regarding inspection and oversight.

Safety in the vicinity of our facilities remains NaTran’s top priority, a fundamental requirement for the effective fulfilment of the company’s public service mission. 

[1] EMAT: an acronym standing for Electro-Magnetic Acoustic Transducer, within the smart pig category. It utilises a specialised inspection technique combining ultrasonic waves and electromagnetism to deliver a thorough and precise evaluation of the pipeline under examination.