A study by internal friction measurements has been made on high purity copper of the effects of 1 MeV electron irradiation on the rate of addition of point defects to dislocations in the temp erature range 78IK to 4OOIK. A distinct minimum in the point defect pinning rate is observed at about 160'K. It is also observed that a peak in the decrement as a function of irradiation time occurs, having a peak position time dependence which reflects the rate at which point defects arrive at dislocations. The above observations are discussed and taken as direct experimental evidence in support of the thermal conversion model. The maximum in internal friction and the minimum in the pinning rate are accounted for in a model of damping due to the dragging of points defects by dislocations. * Work supported by the Metallurgy and Materials Program of the Division of Research, U. S. Atomic Energy Commission, Contract AT(11-1)-1800. LEGAL NOTICE J This report was prepared as an account of work ' sponsored by• the United States Government. Neither the United States nor the United States Atomic Energy Commission, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.
Experimental results from six recent Power Burst Facility (PBF) reactivity initiated accident (RIA) tests are compared with data from previous Special Power Excursion Reactor Test (SPERT), and Japanese Nuclear Safety Research Reactor (NSRR) tests. The RIA fuel behavior experimental program recently started in the PBF is being conducted with coolant conditions typical of hot-startup conditions in a conmercial boiling water reactor. The SPERT and NSRR test programs investigated the behavior of single or small clusters of light water reactor (LWR) type fuel rods under approximate room temperature and atmospheric pressure conditions in capsules containing stagnant water. As observed in the SPERT-and NSRR tests, energy deposition, and consequent enthalpy increase in the PBF test fuel, appears to be the single most important variable. However, the consequences of failure at boiling water hot-startup system conditions appear to be more severe than previously observed in either the stagnant capsuls SPERT or NSRR tests. Metal 1ographic examination of both previously unirradiated and irradiated PBF fuel rod cross sections revealed extensive variation in cladding wall thicknesses (involving considerable plastic flow) and fuel shattering along grain boundaries in both restructured and unrestructured-tu&\-cesLJons. Oxidation of the cladding resulted in fracture at the location of cladding thinning and disintegration of the rods during quench. In addition, swelling of the gaseous and potentially volatile fission products in previously irradiated fuel resulted in volume increases of up to 180% and blockage of the coolant channels within the flow shrouds surrounding the fuel rods.
A study by internal friction measurements has been made on high purity copper of the effects of 1 MeV electron irradiation on the rate of addition of point defects to dislocations in the temp erature range 78IK to 4OOIK. A distinct minimum in the point defect pinning rate is observed at about 160'K. It is also observed that a peak in the decrement as a function of irradiation time occurs, having a peak position time dependence which reflects the rate at which point defects arrive at dislocations.The above observations are discussed and taken as direct experimental evidence in support of the thermal conversion model. The
• 23. Overall view of the posttest Test PCM-2 fuel Rods UTA-0008 and UTA-0009 showing macrophotographic outlays of the metallographic samples examined and their sectioning locations along the fuel rods. .. .. . 24. Overall view of the posttest Test PCM-2 fuel Rods UTA-0010 and A-0014 showing macrophotographic outlays of the metallographic samples examined and their sectioning locations along the fuel rods. .. .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.