SIST EN IEC 62397:2026

Overview

SIST EN IEC 62397:2026, titled Nuclear power plants - Instrumentation and control important to safety - Resistance temperature detectors (IEC 62397:2022), sets forth comprehensive requirements for resistance temperature detectors (RTDs) used in the instrumentation and control (I&C) systems of nuclear power plants (NPPs). These RTDs play a critical role in both safety and non-safety related instrumentation systems, directly impacting the reliability and security of nuclear operations. The standard addresses the entire lifecycle of RTDs, including design, material selection, manufacturing, calibration, procurement, and inspection, ensuring their suitability for demanding nuclear environments.

This standard supersedes previous editions and incorporates technical updates and terminology refinements to align with advancements in the field and regulatory expectations. Both direct-immersed and thermowell-mounted RTDs as well as certain special design RTDs fall under its scope.

Key Topics

SIST EN IEC 62397:2026 covers the following key areas relevant to RTDs in nuclear power facilities:

• Design Requirements

  • Considerations for mechanical, electrical, and environmental robustness
  • Selection of suitable resistance element materials, such as platinum
  • General and application-specific construction recommendations

• Material Selection

  • Requirements for resistance to radiation, fast neutron damage, and environmental stressors
  • Compatibility with nuclear plant operation temperatures and chemical exposures

• Manufacturing and Quality Assurance

  • Processes ensuring long-term reliability and repeatability
  • Traceable manufacturing controls and documentation procedures

• Testing and Calibration

  • Benchmarks and procedures for initial calibration and ongoing verification
  • In-situ testing requirements for functional performance under operating conditions
  • Performance criteria such as response time, accuracy, electrical insulation, and repeatability

• Inspection and Procurement

  • Required tests upon receipt and prior to installation
  • Supplier qualification and documentation needs

• Categorization of RTDs

  • Coverage of both direct-immersed and thermowell-mounted designs
  • General requirements for other specialized RTD applications

Applications

RTDs covered by this standard are vital for:

• Safety-critical temperature monitoring

  • Monitoring reactor core, coolant, containment and other vital systems
  • Ensuring timely detection of abnormal temperatures or component degradation

• Process control and operational monitoring

  • Supporting both safety and process I&C systems, providing primary temperature feedback in steam and water circuits

• Qualification for harsh environments

  • Ensuring continued performance under extreme thermal, vibrational, and radiation conditions typical of nuclear facilities

• Regulatory compliance

  • Supporting nuclear licensees in meeting national and international safety directives and enabling reliable plant operation

Related Standards

SIST EN IEC 62397:2026 references and complements several other key standards for nuclear I&C and equipment qualification:

• IEC 60068-2-6: Environmental testing - Vibration tests
• IEC 60068-2-30: Environmental testing - Damp heat, cyclic
• IEC 60751: Industrial platinum resistance thermometers and platinum temperature sensors
• IEC/IEEE 60780-323: Electrical equipment important to safety - Qualification
• IEC/IEEE 60980-344: Equipment important to safety - Seismic qualification
• IEC 61513: General requirements for I&C systems important to safety
• Relevant IAEA safety guides: On system classification and electrical/I&C design for NPPs

SIST EN IEC 62397:2026 is aligned with international safety directives (such as the Nuclear Safety Directive 2009/71/EURATOM) and supports harmonization across European nuclear power organizations, promoting reliability, traceability, and excellence in safety instrumentation.

Keywords: SIST EN IEC 62397:2026, IEC 62397:2022, nuclear power plant RTD standard, resistance temperature detector, nuclear safety instrumentation, I&C systems, RTD qualification, RTD calibration, nuclear instrumentation standards, nuclear facility RTDs, thermowell-mounted RTDs, direct-immersed RTDs, safety compliance in nuclear power plants.