Embrittlement of nuclear reactor pressure vessels

Neutron irradiation embrittlement could limit the service lift of some of t he reactor-pressure vessels in existing commercial nuclear-power plants. Im proved understanding the of the underlying causes of embrittlement has prov ided regulators and power-plant operators better estimates of vessel-operat ing margins. This article presents an overview, of embrittlement, emphasizi ng the status of mechanistic understanding and models, and their role in in creasing the reliability of vessel-integrity assessments. Finally, a number of outstanding issues and significant opportunities, including new, fractu re-toughness master-curve method, are briefly described.