METHOD TO ASSESS EXTENT OF EMBRITTLEMENT OF MATERIALS OF VVER-1000 REACTOR VESSELS CAUSED BY THERMAL AGEING Russian patent published in 2014 - IPC G01N25/00 

FIELD: power engineering.

SUBSTANCE: reactor vessel steel samples are heated to temperature from 300°C, their further ageing is carried out at this temperature within certain time, subsequent tests of samples are carried out for impact bending, and test results are analysed to determine the value of the shift of critical brittleness temperature, at the same time samples of reactor vessel steel in process of ageing at the temperature of reactor vessel operation of 300-320°C are additionally exposed to neutron radiation with flux of 10¹¹-10¹³ n/cm²·sec for 10³ hours, after that they perform baking at the temperature of 400-450°C with duration of at least 30 hours, and assessment of extent of steel embrittlement is determined using the value of shift of critical brittleness temperature ΔT_k(t) as a result of thermal ageing for the time making more than 5·10⁵ hours, in accordance with a certain mathematical expression.

EFFECT: increased accuracy of assessment of extent of embrittlement of VVER-1000 reactor vessel embrittlement as a result of thermal ageing.

3 tbl