Ductile-to-brittle Transition Temperature of Thermally Segregated WWER-1000 Base Metal

A series of thermal treatments on typical WWER-1000 reactor pressure vessel base metal have been carried out in order to induce large phosphorus segregation. In particular, two conditions have been achieved with significantly different ductile-to-brittle transition temperatures, when compared to un-treated metal, and measured by means of standard Charpy impact tests. Tensile properties, hardness and other non-destructive techniques have also been investigated and when possible correlations established. This study confirms that when phosphorus segregation leads embrittlement, which is directly detected by Charpy testing, due to the non-hardening nature of the embrittlement mechanism neither hardness nor the other applied non-destructive testing (thermoelectric, magnetic Barkhausen and positron annihilation) provides substantial indication of material degradation. The results obtained are an important source of information to understand the behaviour of materials prone to phosphorus segregation; in particular for what regards their sensitivity to fracture.

ACOSTA IBORRA Beatriz;  DEBARBERIS Luigi;  MORETTO Pietro;  ZEMAN Andrej;  PIRFO Soraia;  CHERNOBAEVA Anna;  NIKOLAEV Y.; 

2007-08-20

Inderscience

JRC33520

https://publications.jrc.ec.europa.eu/repository/handle/JRC33520,