Resolution of Generic Safety Issues: Item A-11: Reactor Vessel Materials Toughness (Rev. 2) ( NUREG-0933, Main Report with Supplements 1–35 )
DESCRIPTION
Because of the remote possibility of failure of nuclear reactor pressure vessels designed to the ASME Boiler and Pressure Vessel Code, the design of nuclear facilities does not provide protection against reactor vessel failure. Prevention of reactor vessel failure depends primarily on maintaining the reactor vessel material fracture toughness at levels that will resist brittle fracture during plant operation. At service times and operating conditions typical of existing operating plants, reactor vessel fracture toughness properties provide adequate margins of safety against vessel failure; however, as plants accumulate more and more service time, neutron irradiation reduces the material fracture toughness and initial safety margins. This item was originally identified in NUREG-03712 and was later declared a USI in NUREG-0510.186
CONCLUSION
This USI was RESOLVED with the issuance of NUREG-0744, 743 Revision 1, which was later transmitted to all licensees with Generic Letter 82-26. 744
REFERENCES
|