Completing first-of a-kind intervention: Blayais nuclear reactor’s primary elbow replacement in France

As part of the long-term operation program of the French nuclear fleet (“Grand Carénage”), Tractebel is supporting EDF in replacing components of the primary loop . In this framework, this first-of-a-kind, highly technical intervention is the result of nearly seven years of preparation and combined effort between the ALTRAD ENDEL and Tractebel teams.

Success at Blayais nuclear power plant

The replacement of Blayais 3’s C elbow, weighing three tonnes and measuring 90 cm in diameter, was performed during an outage by the ALTRAD ENDEL team with our support. Tractebel was on site all summer to:

• control the clamping systems to maintain the steam generators in place during cutting, move them to the docking position and release them during welding
• pilot various robotized non-destructive testing operations after welding
• support the project management

In the back office, our experts were also mobilized to calculate residual stresses in the post-intervention loop, line displacements for hot shimming, and support the field teams with civil engineering expertise.

Preparing for the intervention

Preparation began in September 2017, with the call for tenders. The preliminary design was finished in April 2019. The year 2020 was marked by design studies and necessary developments. To prepare for the intervention, ALTRAD ENDEL and Tractebel engineers performed the operation on a full-scale model to qualify the operations.

In 2020 and 2021, the 1:1 scale model of the primary loop, including the steam generator and primary pump casemates, was designed by Tractebel and manufactured and installed by ALTRAD ENDEL in Rognac, France. The model enabled testing, developments, qualifications, and training sessions for the operators.

Multidisciplinary expertise key to project success

Our experts are responsible for the loop calculations, civil calculations, and mechanical expertise crucial to the elbow replacement project. Tractebel’s competences in structural integrity and civil and mechanical engineering were key to helping the French nuclear operator carry out this project.

	“This first maintenance operation of the elbow replacement project at Blayais was highly technical. Our experts contributed to completing it successfully in the shortest possible time. I congratulate our engineers and the ENDEL team for this achievement. I also thank EDF for the constructive collaboration with our experts that led to this success.”
Augustin de la Motte, Tractebel

	“A great success for the steam generator project and the Replacement of Primary Circuit Components package. Well done to the ALTRAD ENDEL and Tractebel teams for rising to this challenge, alongside the DIPDE (Nuclear Fleet and Environment Engineering Division) teams in a spirit of collaboration.”
Arnaud Martin, EDF

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