Introduction
When environmental constraints evolve and regulatory acoustic requirements become stricter, an out-of-specification exhaust system can block commissioning of the plant and expose the operator to major documentary non-compliance.
Groupe Boët intervened to deal precisely with this situation, without compromising nuclear qualification requirements.
The emergency diesel unit: a critical piece of equipment
The diesel emergency power unit in a nuclear power plant is not subject to the same rules as standard industrial equipment. Its exhaust system must simultaneously meet strict acoustic requirements, mechanical integrity criteria under accident conditions and a rigorous qualification documentation framework, defined by the operator’s specifications and the obligations of ISO 19443.
Any modification to this network involves the entire qualification chain: aeraulic analyses, mechanical strength checks, acoustic justifications and complete documentary traceability.
In this context, noise control cannot be dissociated from nuclear safety requirements. These two dimensions must be addressed jointly, right from the design phase.
Non-compliant exhaust systems: operational consequences
Changes in the environmental constraints applicable to the site had rendered the existing exhaust system non-compliant with the new acoustic requirements. This exceedance of permissible thresholds exposed the operator to the risk of blocking commissioning of the standby unit, with direct consequences for plant availability and regulatory compliance.
Groupe Boët’s challenge was therefore to completely modify the existing network, integrating a new engine silencer engine muffler. The work had to be carried out in a real nuclear environment, without prolonged interruption of the unit’s availability, and with a complete qualification file that could be traced and used against the operator.
Solution: industrial silencers designed and qualified in-house
Groupe Boët took charge of the entire project, from constraints analysis to manufacturing, without subcontracting critical phases.
Diagnosis and qualification of needs
The first step was to analyze the new environmental constraints and define the acoustic and mechanical performance objectives to be achieved. This diagnostic phase led to the drafting of a qualification note covering aeraulic aspects, mechanical integrity andnoise attenuation performance, integrating applicable normative developments and the customer’s specific requirements.
Engine exhaust silencers manufacture
On this basis, Groupe Boët has designed, qualified and manufactured an Engine exhaust silencers adapted to the diesel emergency power unit, complying with customer specifications and ISO 19443 requirements. The design was dimensioned to ensure the silencer’s mechanical strength under accident conditions, as defined by the nuclear environment – a decisive criterion for qualification of this type of equipment. The entire design-manufacturing chain was internalized, guaranteeing total control over quality and documentary traceability.
Certifications
Groupe Boët is ISO 9001 and ISO 19443 certified, and masters the main international construction codes applicable in the nuclear environment: EN 13480, EN 13445, ASME, RCC-M, CODAP and CODETI.
Results: Documentary compliance and validated performance
The silencer integrated into the exhaust system meets all the requirements defined during the qualification phase. The acoustic performance achieved complies with the new regulatory thresholds applicable to the site. Mechanical strength under accident conditions has been justified in the qualification file, in accordance with the obligations imposed by the nuclear environment. Compliance was achieved without prolonged immobilization of the diesel backup unit, thus preserving the plant’s operational availability.
The qualification file delivered to the operator is complete, traceable and enforceable: it covers all the technical justifications required for this type of acoustic protection equipment in nuclear power plants.
Industrial acoustics in a nuclear environment: mastered expertise
This project illustrates Groupe Boët’s ability to work on applications where acoustic, mechanical and documentation requirements are inseparable. Complete mastery of the design-qualification-manufacturing chain is a sine qua non for intervention in nuclear safety. For all your needs in industrial silencers or noise treatment for critical equipment, contact Groupe Boët for a technical analysis tailored to your regulatory and safety constraints.