Description: Experimemts using Cl/sup 36/ in a steam test loop were conducted to study the deposition behavior of chlorides on BONUS superheater fuel assembly materials. The moisture content of the steam was varied between 0 and 0.5 wt%, and superheat was added up to 15 deg F before the steam passed over the test cartridge heater. The effects of vaiiables on the chloride deposition on the heater were studied in detail. Chloride deposition from moist steam was found to result in heavy, adherent deposits which are conducive to severe chloride stress corrosion of austenitic steels, while removal of all moisture from the incoming steam reduces the chloride deposition and minimizes the chloride stress corrosion. The heater surface condition was found to be a very important variable; deposition is increased by surface defects and pits. Neither the temperature of steam or heater nor the amount of superheat had an appreciable effect on the deposition, when no moisture existed in the steam. However, low steam velocities and spacer protoberances increase the deposition. Different clad materials (Inconel and Type 304 and 347 stainless steel) with similar surface conditions did not affect the deposition, although subsequent corrosion effects do modify the deposition behavior. Recommendations are given for the control of chloride deposition in nuclear superheater reactor systems. (D.L.C.)
Date: October 18, 1963
Creator: Bevilacqua, F. & Brown, G.M.
Partner: UNT Libraries Government Documents Department