Classification & Function
System boundary, credited function, safety significance, equipment interfaces and applicable owner, regulatory and code requirements.
Nuclear Island · Turbine Island · SMR
Nuclear Power Plant Insulation Systems
ERATHERM develops project-specific insulation solutions for nuclear new-build, retrofit, outage and SMR programmes—coordinating thermal performance, plant classification, environmental conditions, accident interfaces, mechanical retention, maintainability and nuclear-quality documentation within one controlled scope.
Engineering review, thermal calculations, qualified material procurement, removable and metallic systems, fabrication, installation, QA/QC, outage reinstatement and as-built close-out.
Design-Basis Integration
RMI & Removable Systems
Supply & Fabrication
QA & Traceability
Conceptual Engineering Visual
15,000+ MWPower-Generation Field Experience
1,000,000+ m²Industrial Insulation Application Experience
PWR · BWR · SMRPlant-Specific Engineering Readiness
One Integrated ScopeEngineering, Supply, Installation and QA/QC
Thermal Performance Within the Plant Safety Basis
Why Nuclear Insulation Is More Than Heat-Loss Control
Depending on its location and credited function, an insulation system can influence equipment temperature, personnel protection, fire loading, inspection access, outage dose, seismic behaviour and accident-generated debris.
Nuclear service does not create one universal insulation specification. Requirements change between containment, the nuclear island, turbine island, auxiliary buildings and balance-of-plant systems—and they also change between PWR, BWR, SMR and advanced-reactor designs.
ERATHERM therefore develops the insulation package against the plant licensing basis, owner requirements, EPC and OEM data, equipment classification, operating and accident conditions, maintenance strategy and the contractually flowed-down quality programme.
01 · Plant and Scope Boundaries
One Plant, Several Insulation Design Environments
The package is divided by system function, location, classification and exposure before any material or construction detail is selected.
Nuclear island and containment
Turbine island and steam cycle
Safety and safety-support systems
HVAC and controlled environments
Emergency power and auxiliary systems
Balance-of-plant utilities
New-build and modular construction
Brownfield replacement and uprates
Planned outages and reinstatement
Decommissioning and controlled removal
PWR- or BWR-specific equipment
SMR and advanced-reactor interfaces
Plant-specific scope: Equipment such as steam generators and pressurizers is not common to every reactor design. Final asset lists follow the selected technology, OEM configuration and plant system boundaries.
02 · Nuclear Design Basis
Five Interdependent Reviews Define the System
The required depth is established by the owner or design authority according to safety significance, location and the plant licensing basis.
Normal & Transient Duty
Operating temperatures, start-up, shutdown, cycling, heat retention, safe surfaces, condensation and process stability.
Accident Environment
Applicable LOCA or HELB conditions, jet impingement, pressure and temperature transients, spray chemistry, flooding and post-accident function.
Qualification & Retention
Integrated dose, ageing, fire, seismic loading, supports, fasteners, foreign-material control and debris-generation characteristics.
Lifecycle & Outage
Inspection access, ALARA-informed work planning, removable zones, identification, repeatable reinstatement, spares and configuration control.
Controlled engineering chain
Plant Classification→Design Conditions→Qualification Basis→System Definition→Verified Configuration
03 · Nuclear-Specific Performance Engineering
Thermal Design Must Be Coordinated with Safety and Plant Interfaces
Thermal calculations establish normal performance; separate project analyses determine qualification, accident and structural acceptance where required.
Heat Flow & Surface Temperature
Heat loss or gain, personnel-contact criteria and equipment heat balance under defined operating and ambient cases.
Layer & Interface Temperatures
Temperature profile through insulation, metallic foils, encapsulation, fasteners, coatings and adjacent components.
Transient Thermal Response
Start-up, shutdown, cooldown or heat-up response when required by equipment operation or safety analysis inputs.
Thermal Bridges & Penetrations
Supports, straps, cassette frames, instrument openings and other three-dimensional heat-flow paths.
Mechanical & Seismic Interfaces
Retention concept, clearances, differential movement and load paths coordinated with the responsible structural and equipment disciplines.
Accident & Debris Inputs
Insulation inventory, location, destruction characteristics and debris data prepared for the licensee's LOCA, HELB, sump or strainer assessment.
04 · Nuclear Insulation Architectures
System Selection by Location, Function and Qualification Route
All-Metal, Removable Thermal Architecture
- Stainless-steel shells and separated reflective foils
- Reusable cassettes for defined equipment geometries
- Reduced fibrous inventory where project analysis requires it
- Qualified supports, closures and accident-debris data
Maintainable Cassettes and Insulation Jackets
- Stainless outer skin with project-qualified insulation core
- Tagged modules for valves, flanges and complex equipment
- Controlled seams, fasteners, penetrations and inspection ports
- Repeatable dismantling, storage and reinstatement process
Turbine Island and Balance-of-Plant Systems
- Steam piping, turbines, feedwater and auxiliary equipment
- Mineral, calcium-silicate, aerogel or cellular systems as approved
- Weatherproofing, drainage and CUI control
- Outage-ready removable areas and inspection access
Condensation, Vapour and Cleanliness Control
- Chilled-water and low-temperature utility systems
- Continuous vapour-control and sealed support interfaces
- Cleanable finishes for controlled plant locations
- Fire, smoke and contamination requirements by area
RMI is not spacecraft MLI.
Reflective metallic insulation used on nuclear plant equipment operates without a space-type vacuum blanket. Its thermal performance, cassette construction, retention, testing and accident-debris behaviour require a plant-specific engineering and qualification basis.
05 · Complete Assembly Definition
Every Interface Must Remain Controlled Through the Plant Lifecycle
The build-up changes by plant area, but the review follows the complete assembly from equipment surface to identification and as-built records.
- 1Equipment Surface & Coating
Surface condition, coating compatibility, cleanliness, stainless-steel chemistry and corrosion-control basis.
- 2Thermal Core or Reflective Pack
Approved product, layer geometry, design properties, ageing basis and joints.
- 3Encapsulation & Boundary Control
Metal shells, liners, foils, membranes, seams, penetrations and contamination-control requirements.
- 4Supports, Restraints & Clearances
Load transfer, seismic retention, differential movement, equipment access and pressure-boundary interfaces.
- 5Removable Modules & Access
Cassette segmentation, closures, lifting, inspection windows, dismantling sequence and storage.
- 6Identification & Configuration
Unique tags, material lots, drawing status, location control, hold points and post-maintenance verification.
06 · Material and System Qualification
“Nuclear Grade” Is a Documented Project Status—not a Generic Product Label
Candidate systems are evaluated against the approved specification, plant environment, qualification programme and procurement quality requirements.
Thermal & Ageing
- Design conductivity at relevant temperature
- Service and transient temperature limits
- Thermal cycling and long-term ageing
- Radiation dose and combined-environment data
Chemistry & Corrosion
- Water-leachable chloride and fluoride
- Silicate and sodium chemistry where specified
- Stainless-steel stress-corrosion evaluation
- Coating, sealant and decontamination compatibility
Fire & Environment
- Combustible loading and flame/smoke criteria
- Humidity, spray, flooding and chemical exposure
- Cleanability and contamination control
- Post-event condition and recovery requirements
Mechanical & Debris
- Seismic and vibration retention
- Jet-impingement or ZOI response where applicable
- Debris size, transport and chemical-effects inputs
- Foreign-material and fibre-release control
Why no universal material table?
Mineral fibre, calcium silicate, aerogel, cellular glass, ceramic fibre or metallic systems are not automatically acceptable for every nuclear location. Product formulation, total integrated dose, accident environment, leachable chemistry, fire performance, mechanical retention, debris characteristics and procurement controls must be verified for the defined application.
07 · Nuclear Project Workflow
A Traceable Path from Classification to Verified Reinstatement
- 01
Classification & Input Review
Plant area, system function, equipment status, licensing basis, specifications, QA level and missing data.
- 02
Design-Basis Definition
Normal, transient, accident, radiation, seismic, fire, chemistry, maintenance and access requirements.
- 03
Engineering & Analysis
Thermal calculations, interfaces, materials, segmentation, retention and maintainability.
- 04
Qualification Evidence
Applicable tests, calculations, similarity evidence, limitations, supplier data and acceptance route.
- 05
Procurement & Fabrication
Approved suppliers, material lots, drawings, BOM, traveller records, inspections and release status.
- 06
Installation & QA/QC
Cleanliness, FME, hold points, fit-up, fastening, identification, NCR control and turnover records.
- 07
Outage & As-Built Control
Dismantling, controlled storage, reinstatement, condition checks, revisions and configuration close-out.
08 · Nuclear Insulation Deliverables
Coordinated Records for Design, Procurement, Installation and Operation
The package is scaled to the project's safety significance, contractual QA level, design stage and owner document-control procedure.
Design-Basis & Classification Register
Plant boundaries, functions, applicable conditions, requirements, assumptions, interfaces and approval authorities.
Thermal Calculation Report
Property basis, operating cases, heat flow, surface and layer temperatures, interfaces and sensitivities.
Material Qualification Matrix
Approved products, test evidence, environmental limits, chemistry, ageing data and documented restrictions.
Accident-Debris Data Package
Insulation inventory, location, construction, potential debris characteristics and inputs for owner safety analysis.
Drawings, Segmentation & BOM
Equipment-specific layouts, cassette numbering, supports, closures, access features, quantities and spares.
Procurement & Fabrication Records
Supplier approvals, certificates, lot traceability, traveller records, inspections, deviations and release notes.
ITP and Installation Dossier
Hold points, method statements, FME controls, fit-up checks, photographs, NCRs and turnover records.
Outage and As-Built Package
Dismantling maps, storage controls, reinstatement records, final configuration, revisions and maintenance guidance.
Need fabrication-ready cassette and cladding drawings?
Explore Insulation Shop Drawing Preparation →
The approved nuclear design basis can be converted into project-specific shop drawings, segment maps, component tags, cutting lists and drawing-linked BOM/MTO.
09 · Nuclear Technical Framework
Codes and Standards Applied Within Their Actual Scope
The licensing basis, jurisdiction, owner specifications, contract edition and document hierarchy govern. None of the references below is a universal stand-alone nuclear insulation code.
IAEA SSR-2/1 (Rev. 1)
High-level safety requirements for nuclear power plant design, including classification, environmental conditions, ageing and maintainability principles.
ASME NQA-1Nuclear quality-assurance requirements when invoked by contract, regulation or the owner's approved QA programme.
ISO 19443:2018Quality-management requirements for nuclear supply-chain products and services important to nuclear safety, with applicable amendments.
ASME BPVC Section IIIConstruction rules for nuclear facility components and supports—not a blanket classification for external thermal insulation.
RCC-MDesign and construction rules for mechanical components of PWR nuclear islands where contractually applicable.
NRC RG 1.82 Rev. 5 / GL 2004-02US regulatory framework addressing accident-generated debris and emergency-recirculation performance in applicable light-water reactors.
ASTM C795 / C692 / C871Non-metallic insulation chemistry and stress-corrosion evaluation for contact with austenitic stainless steel.
Plant Licensing Basis
Owner, regulator, EPC and OEM requirements determine classification, qualification, fire, seismic, radiation, debris, procurement and acceptance criteria.
10 · Nuclear Plant Applications
Project-Specific Systems Across the Plant
Reactor Vessel External Insulation
Steam Generator & Pressurizer
Primary-System and Main-Steam Piping
ECCS, RHR and Safety-Support Systems
Valves, Flanges and Inspection Points
Containment Penetrations and Interfaces
Steam Turbines and Feedwater Systems
HVAC, Chilled Water and Controlled Areas
Emergency Power and Exhaust Systems
SMR Modules and Thermal Barriers
The ERATHERM Delivery Model
Nuclear-Project Discipline Supported by Power-Generation Field Experience
Design-Authority Awareness
Classification, credited functions and final acceptance remain aligned with the owner, licensee, EPC, OEM and responsible engineering disciplines.
Field-Ready Engineering
More than 1,000,000 m² of industrial application experience informs access, tolerances, segmentation, installation and outage reinstatement.
Integrated Delivery
Engineering, calculation, qualified sourcing, fabrication, installation, inspection, training and close-out can be coordinated under one scope.
Traceability by Requirement
QA controls are established at contract award; material, drawing, inspection and as-built records follow the approved project programme.
Quality-status statement
References to NQA-1, ISO 19443, ASME Section III or RCC-M describe possible project frameworks. They do not state that ERATHERM or every supplied insulation product holds a particular nuclear certificate. Required certification, supplier qualification, audits and QA programme flow-down must be confirmed for each contract.
Frequently Asked Questions
Nuclear Power Plant Insulation Systems
What makes nuclear power plant insulation different from conventional power plant insulation?
Depending on location and function, nuclear insulation may require controlled safety classification, radiation and ageing data, seismic retention, fire and chemical compatibility, LOCA or HELB debris inputs, foreign-material control, nuclear-quality procurement and configuration-managed maintenance records in addition to thermal performance.
Is insulation installed on ASME Section III equipment automatically Class 1, 2 or 3?
No. ASME Section III defines rules for nuclear facility components and supports. The owner or design authority determines whether an insulation assembly, its support or an attachment has a code or safety classification and identifies the applicable design, procurement, inspection and documentation requirements.
How is ASME NQA-1 applied to an insulation project?
NQA-1 applies when it is invoked by regulation, contract or the owner's approved quality programme. The flowed-down scope can include design control, procurement, supplier qualification, document control, inspections, test-equipment control, nonconformance management, records and audits. A reference to NQA-1 does not by itself prove certification.
What is reflective metallic insulation in a nuclear plant?
Reflective metallic insulation, or RMI, is an all-metal assembly that reduces heat transfer through separated reflective foils inside removable metal cassettes. It is different from vacuum MLI used in spacecraft and cryogenic vessels and requires project-specific thermal, mechanical, retention and accident-debris evaluation.
How are LOCA and HELB insulation-debris risks addressed?
The applicable plant analysis can require insulation inventory, location, zone-of-influence assumptions, destruction characteristics, debris size distribution, transport behaviour and chemical-effects inputs. ERATHERM can develop the insulation data package, while the licensee or appointed design authority retains the integrated safety analysis.
Are mineral wool, calcium silicate, aerogel or cellular glass automatically nuclear qualified?
No. Acceptance is product- and application-specific. The approved basis may need thermal and ageing data, total integrated dose, leachable chemistry, stainless-steel compatibility, fire behaviour, mechanical retention, accident-environment response, debris characteristics and qualified supplier records.
Can ERATHERM support both nuclear-island and turbine-island insulation?
Yes. The scope can cover nuclear-island, containment, turbine-island, HVAC, emergency-power and balance-of-plant applications. Each area is separated by classification, qualification, cleanliness, fire, environmental and documentation requirements.
How do removable insulation systems support planned outages?
Project-specific cassettes or jackets can be segmented, tagged and documented for controlled dismantling, storage, inspection and repeatable reinstatement. The design must maintain required thermal performance, access, fastener control, cleanliness, FME and configuration records through repeated cycles.
How is corrosion under insulation controlled in a nuclear facility?
The design coordinates substrate coating, insulation chemistry, water-entry paths, drainage, cladding seams, removable inspection zones and plant environmental conditions. ASTM C795, C692 and C871 may support stainless-steel material evaluation, but they do not replace the plant corrosion and ageing-management programme.
Can ERATHERM provide engineering, materials, fabrication, installation and QA/QC?
Yes. ERATHERM can coordinate design review, calculations, material and supplier evaluation, shop drawings, BOM/MTO, procurement, cassette or cladding fabrication, installation, inspection, outage reinstatement, training and as-built close-out. Final classification and nuclear qualification remain subject to the owner-approved project framework.
Start with Classification and Design Conditions
Request a Nuclear Power Plant Insulation Review
Share the plant technology, system and equipment list, project phase, operating and accident conditions, drawings, classification, owner specifications and applicable QA requirements. ERATHERM will define the engineering, qualification-support and delivery scope.