tailieunhanh - Nuclear Power Control, Reliability and Human Factors Part 9

Tham khảo tài liệu 'nuclear power control, reliability and human factors part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Degradation Due to Neutron Embrittlement of Nuclear Vessel Steels A Critical Review about the Current Experimental and Analytical Techniques. 229 Guthrie 1984 and Odette et al. 1984 . Both contributions used surveillance data from commercial power reactors. The bases for their regression correlations were different in that Odette made greater use of physical models of radiation embrittlement. The two papers contain similar recommendations 1 separate correlation functions should be used for weld and base metal 2 the function should be the product of a chemistry factor and a fluence factor 3 the parameters in the chemistry factor should be the elements copper and nickel and 4 the fluence factor should provide a trend curve slope of about to on log-log paper at 1019 n cm2 E 1 MeV steeper at low fluences and flatter at high fluences. ARTndT CF f f 7 CF F in equation 7 is the chemistry factor a function of copper and nickel content. CF is tabulated in RG 2 1988 for welds and base metal plates and forgings . Linear interpolation is permitted. If there is no information available copper and nickel should be assumed. The neutron fluence at any depth x in the vessel wall f x 1019 n cm2 E 1 MeV is determined following equation 8 f x fSUi ỉ e 8 where fsurf 1019 n cm2 E 1 MeV is the calculated value of the neutron fluence at the inner surface of the vessel and x in inches is the depth in the vessel wall measured from the vessel inner surface. Alternatively if dpa calculations are made as part of the fluence analysis the ratio of dpa at the depth in question to dpa at the inner surface may be substituted for the exponential attenuation factor in equation 8 . The third term in 6 M is the quantity F that is to be added to obtain conservative upperbound values of the adjusted reference temperature. M is obtained through equation 9 . M 2 V U ơỉ 9 Here Ou is the standard deviation for the initial RTndt. If a measured value of initial RTndt .