Evaluation of Commercial Production A533-B Steel Plates and Weld Deposits with Extra-Low Copper Content for Radiation Resistance.

摘要

A cooperative research program by the U.S. Nuclear Regulatory Commission (NRC),Combustion Engineering,Inc., (CE),and the Naval Research Laboratory (NRL) has explored trends in radiation effects for commercially produced ASTM A533-B steel plates,weld deposits,and weld heat-affected zones,depicting three levels of control over impurity copper content. The primary objective was to establish the trend of improved 288 C (550 F) radiation resistance with progressive reductions in allowable copper content. An overall objective was to develop information assisting the formulation of special specifications for steels for nuclear service and the delineation of associated embrittlement trends for reactor vessel design and operation. This report describes investigations on Series 3materials,which represent optimum steel-making practice,and a limitation on copper content of 0.06% Cu maximum. Previous investigations on Series 1materials (=or > 0.15% cu) typical of nonimproved steel production (pre-1971) and Series 2materials (0.10% Cu,max) representative of improved steel production (current practice) are also summarized. Radiation resistance was assessed from Charpy-V (Cv) notch ductility changes with fluences of approx. 5to 7 x 10to the 19th power n/sq cm > 1MeV. All Series 3materials exhibited high resistance to radiation in terms of both transition temperature elevation and upper shelf degradation. Typically,the postirradiation Cv 41 J(30ft-lb) transition-temperature elevation was less than 56 C (100 F).