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Irradiation by fast neutrons has a significant effect on the microstructure of the reactor pressure vessel (RPV) material in the RPV beltline region resulting in material property changes. The strength of the material increases and fracture toughness decreases. Neutron-induced embrittlement of vessel materials is characterized by determining the increase of the nil-ductility-transition reference temperature (RTNDT). This is verified by AREVA NP’s Irradiation Assessment Program.

The Reactor Pressure Vessel Irradiation Assessment provides: 

  • Consultation, planning, coordination, execution including mitigation measures
  • Baseline testing, manufacturing of specimens and capsules, delivery to the nuclear power plant (NPP)
  • Withdrawal of capsules from the RPV and transport to the hot cells test lab
  • Dismantling and post-examination of irradiation capsules
  • Specimen testing, examination of temperature and flux monitors in hot cells
  • Flux calculations, safety assessment and documentation of the entire project.

Your benefits

Monitoring of irradiation behavior of RPV and other nuclear components allows safe and economic operation of nuclear reactors and licensing for long-term operation (LTO).


AREVA NP’s Irradiation Assessment has been conducted in over 32 plants worldwide.

Interested in Reactor Pressure Vessel Irradiation Assessment Program?

Download product sheet

Part of the Forward Alliance Catalog. Category: Aging management by component – Reactor pressure vessel (RPV).


CARINA – a programme for experimental investigation of the irridation behaviour of German reactor pressure vessel materials

AREVA NP Germany