Influence of the Depth Position on the Neutron Embrittlement of the VVERReactor Pressure Vessel Steel 15Cr2MoV(A) - Consequences for the Assessment of Reactor Safety


Influence of the Depth Position on the Neutron Embrittlement of the VVERReactor Pressure Vessel Steel 15Cr2MoV(A) - Consequences for the Assessment of Reactor Safety

Böhmert, J.; Bergner, F.; Große, M.; Viehrig, H.-W.

The dependence of the mechanical properties on the depth position in unirra- diated state and after irradiation up to neutron fluences of approximately. 5 x 1018 and 70 x 1018 cm-2 (E > 0.5 MeV) is tested on a forging made of VVER 440 reactor pressure vessel steel 15CrMoV. Specimens taken from a sub-surface region shows a higher strength and a lower transition temperature than ones from 1/4 - 3/4 of the wall thickness. Increased irradiation reduces these differences. The testing of specimes from the 1/4 depth position within the surveillance programme, as normally demanded by monitoring rules for nuclear power plants, results in a conservative safety assessment against brittle fracture even in the case of EOL fluence. By taking into account fluence attenuation, the flux effect etc., the toughness increases over the wall thickness from the inside to the outside after a longer operating time of the RPV.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 1993, Köln, 25. - 27. Mai 1993

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Publ.-Id: 1860