THERMAL STRESS TESTING OF SM-2 FUEL ELEMENTS. Interim Technical Report for January 1, 1959 to January 1, 1960

Thermal stress testing was performed on two fuel plates, one cut from a brazed SM-1 dummy fuel element and the other from a TIG Welded SM-2 reference element. The test specimens were subjected to transverse temperature differences of up to 200 deg F, and distortion and strain at various locations were measured. The effect of the thermal stress was to increase the amplitude of original distortions. Adddtional distortions due to thermal stress were proportional to temperature differential and to ripple length. Tensile stresses in the side plate sections were measured as approximately 10,000 psi at maximum reactor temperature difference. Individual weld loadings in shear were measured as 38 lb per weld. Results of the tests were considered inconclusive because of unrepresentative initial plate distortion. (M.C.G.