Preliminary results of NWT crevice flushing program

The tests performed by NWT were considerably different from those performed by Westinghouse. NWT used a flat plate annulus scaled to be similar to a tube sheet crevice. The flat plate simulator was used because of its simple fabrication, ease of preloading and ease of analysis of the crevice contents following a test. The device and the simulator crevice loading is described. Basically, it was loaded with a mixture of magnetite plus 20% sodium chloride or 14% sodium hydroxide having a toothpaste consistency. The TSCF simulations were performed using either pure water, boric acid, a surfactant or a surfactant and boric acid. An outline of the test procedure is presented and a schematic of the test facility is shown. A summary of the crevice flushing results is given