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Influence of Neutron Energy Spectrum on Primary Damage Formation

Conference ·
OSTI ID:621552
Displacement cascade formation in iron has been investigated by the method of molecular dynamics (MD) for cascade energies up to 40 keV. The results of these simulations have been used to obtain effective, energy-dependent cross sections for two measures of primary damage production: (1) the number of surviving point defects expressed as a fraction of the those predicted by the standard secondary displacement model by Norgett, Robinson, and Torrens (NRT),and (2) the fraction of the surviving interstitials contained in clusters that formed during the cascade event. The primary knockon atom spectra for iron obtained from the SPECTER code have been used to weight these MD-based damage production cross sections in order to obtain spectrally-averaged values for several locations in commercial fission reactors, materials test reactors, a DT fusion reactor first wall, and a pulsed spallation neutron source. An evaluation of these results indicates that neutron energy spectrum differences between the various environments do not lead to significant differences between the average primary damage formation parameters. This conclusion implies that the displacement damage component of radiation damage produced in a high energy spallation neutron source should be well simulated by irradiation in a fission reactor neutron spectrum, and that differences in nuclear transmutation production may be a greater source of uncertainty in the prediction of material performance in the planned National Spallation Neutron Source.
Research Organization:
Oak Ridge National Lab., TN (United States)
Sponsoring Organization:
USDOE Office of Energy Research, Washington, DC (United States); Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC05-96OR22464
OSTI ID:
621552
Report Number(s):
CONF-970201--32; ON: DE97009376; BR: KC0201040; 4181098L1; AT6020000; CNN: Contract DE-AC05-96OR22464
Country of Publication:
United States
Language:
English