Neutron embrittlement mechanisms include: Neutron irradiation embrittlement limits the service life of reactor-pressure vessels (RPV) in nuclear power plants due to the degradation of reactor materials.
To achieve sufficient safety, the design of the reactor assumes large cracks and extreme loading conditions.
Under such conditions, a probable failure mode is rapid, catastrophic fracture if the vessel steel is brittle.
Over the past few decades, RPV embrittlement has been addressed by the use of tougher steels with lower trace impurity contents, the decrease of neutron flux that the vessel is subject to, and the elimination of beltline welds.
To counteract this, many PWRs have a specific core design that reduces the number of neutrons hitting the vessel wall.