Design of pressurized enclosures

Pressurized water reactor (PWR) equipment and circuits are first and foremost pressure vessels. Their specific features primarily concern the integrity guarantees that must be provided, given their importance for nuclear reactor safety. Emphasis is therefore placed on the exhaustive prevention of in-service degradation risks, and on the safety scenarios considered, without fundamentally calling into question the calculation bases for pressure vessels, which also apply to non-nuclear equipment.

The second specificity of using these enclosures in nuclear reactor circuits is the possibility of activation of products resulting from wear or corrosion as they pass through the core. This second aspect is reflected in certain restrictions on the choice of materials used, and in the application of a lining to the internal walls of the primary circuit's major equipment, which may itself generate special construction and analysis precautions.

The purpose of this document is to describe the general approach adopted for the design of pressure vessels for PWR fluid circuits, focusing in particular on the nuclear specificities of this equipment. The approaches shared with non-nuclear equipment are covered by reference to the [A 843] document. The rules applicable to high-temperature equipment (fast breeder reactors) are also discussed.

The [BN 3 282] file completes the present file by covering the concepts of stress classification, the general approach to design and analysis, regulatory tests and equivalence between industrial construction codes.

In the Pour en Savoir Plus section [Doc. BN 3 280] , readers will find all the regulatory texts and codes cited in this dossier.