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The Reactor Pressure Vessel (RPV) material of Nuclear Power Plants (NPP) is exposed to neutron irradiation during its operation. Such exposure is generally inducing a degradation of the mechanical and physical properties of the materials: e.g. an increase of the ductile to brittle, DBTT, transition temperature and a decrease of the upper shelf energy.

The different response of materials to neutron irradiation, even if many factors are also playing a significant role, is mainly due, for a given exposure, to the chemical composition of the materials. In particular, for the RPV steel, elements like phosphorus, P, copper, Cu, and nickel, Ni, are playing a key role.

The effect of fluence rate on irradiation embrittlement of RPV materials is also a key issue for the correct interpretation of accelerated data and surveillance data in view of reactor pressure vessel life assessment of nuclear reactors. Such correct interpretation is important for the plant lifetime assessment and decisions on life extension by means of mitigation methods like annealing. The issue is quite complex and one of the major difficulties is to compare data obtained at different fluence rates combined with large variations of other field parameter, including spectrum, fluence, temperature, gradients, etc. Much effort was done in the last decades to tackle such issue and quite contradictory results have been obtained. ed.

Additional information

Authors: DEBARBERIS L, EC-JRC, Institute for Advance Materials, JRC-IAM, Petten (NL);SEVINI F, EC-JRC, Institute for Advance Materials, JRC-IAM, Petten (NL);ACOSTA B, EC-JRC, Institute for Advance Materials, JRC-IAM, Petten (NL);KRYUKOV A, RRC-KI, Moscow (RU)
Bibliographic Reference: An oral report given at: IAEA Experts Meeting . Sponsored by: IAEA. Held in: Gloucester, 14-17 May 2001
Record Number: 200013611 / Last updated on: 2001-07-30
Original language: en
Available languages: en