Fuel rod mechanical deformation during the PBF/LOFT lead rod loss-of-coolant experiments

Results of four PBF/LOFT Lead Rod (LLR) sequential blowdown tests conducted in the Power Burst Facility (PBF) are presented. Each test employed four separately shrouded fuel rods. The primary objective of the test series was to evaluate the extent of mechanical deformation that would be expected to occur to low pressure (0.1 MPa), light water reactor design fuel rods when subjected to a series of double ended cold leg break loss-of-coolant accident (LOCA) tests, and to determine whether subjecting these deformed fuel rods to subsequent testing would result in rod failure. The extent of mechanical deformation (buckling, collapse, or waisting of the cladding) was evaluated by comparison of cladding temperature and system pressure measurements with out-of-pile experimental data, and by posttest visual examinations and cladding diametral measurements

Thermal-hydraulics of the PFB/LOFT lead rod loss-of-coolant experiments. [PWR]

Results of the four PBF/LOFT Lead Rod sequential blowdown tests conducted in the Power Burst Facility (PBF) are presented. The primary objective of the test series was to evaluate the extent of mechanical deformation that would be expected to occur to low pressure (0.1 MPa), light water reactor design fuel rods subjected to a series of nuclear blowdown tests, and to determine if subjecting deformed fuel rods to subsequent testing would result in rod failure. The extent of mechanical deformation (buckling, collapse, or waisting of the cladding) was evaluated by comparison of cladding temperature versus system pressure response with out-of-pile experimental data, and by posttest visual examinations and cladding diametral measurements. Tests LLR-3, LLR-5, LLR-4, and LLR-4A were performed at system conditions of 595/sup 0/K coolant inlet temperature, 15.5 MPa system pressure, and 41, 46, 57 and 56 kW/m test rod peak linear powers, respectively, at initiation of blowdown. Cladding temperatures during the tests ranged from 870 to 1260/sup 0/K

An SDE study of twin-wire electric arc sprayed nickel-aluminum coatings

An analytical and experimental study of the twin-wire electric arc spraying of nickel-aluminum coatings has been performed to demonstrate the suitability of the wire system as a bond coat material for ceramic overcoats in thermal barrier applications, and for spraying a single coat for part refurbishment. Experiments were conducted using a Box-type full-factorial design parametric study. Operating parameters were varied around the typical process parameters (i.e., current, primary and secondary pressure, spray distance) in a systematic design of experiments (SDE) in order to display the range of processing conditions and their effect on the resultant coating. The coatings were characterized by hardness tests and optical metallography. Coating properties were quantified for hardness, porosity, deposition efficiency, and microstructure. The features of the coatings are correlated with the changes in operating parameters. Analytical calculations of the gas and droplet dynamics are presented, which includes molten metal entrainment and droplet breakup models

A Taguchi experimental design study of twin-wire electric arc sprayed aluminum coatings

An experimental study was conducted on the twin-wire electric arc spraying of aluminum coatings. This aluminum wire system is being used to fabricate heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic experiments. Experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical process parameters in a systematic design of experiments in order to display the range of processing conditions and their effect on the resultant coating. The coatings were characterized by hardness tests, optical metallography, and image analysis. The paper discusses coating qualities with respect to hardness, roughness, deposition efficiency, and microstructure. The study attempts to correlate the features of the coatings with the changes in operating parameters. A numerical model of the process is presented including gas, droplet, and coating dynamics