When water is used as a coolant in any heat-producing process, the purity of the cooling water is of considerable importance, both from the standpoint of build-up of deposited solids inside the cooling tubes, and as an indication of corrosion of the tubes or any other materials with which the water comes in contact. The first problem has long been recognized, and is generally solved by pretreatment of the water. Efficient treatment can reduce the total solids content to less than 0.1 ppm, and the concentration of individual elements to the order of 0.01 ppm. If water of this purity is used, the analysis of the input and output stresses can result in some useful information. The input stream analysis, of course, is direct measure of the quality of the original cooling water, and frequent analysis by a reasonably fast method can be used to keep pretreatment under control. But of even greater significance is the difference in the impurity content of input and output streams. In a simple, straight-through system the difference generally will be negligible. If a closed, recirculating system is considered, however, with the coolant water circulating through the process to be cooled and then through a …

Twelve uranium-magnesium fuel material samples have been irradiated in the MTR at the request of the Pile metallurgy Unit. These samples were 0.40 inch in diameter by 1.5 inches long and were canned in Zircalloy-2 capsules. The uranium used in these specimens was in the form of chips which packs about 50 volume percent. Six of the samples contained a matrix of pure magnesium and the other six contained an alloy matrix of magnesium - 1.4 weight percent silicon. Two specimens of each matrix material were irradiated to 1000 MWD/T and a like number to 5000 MWD/T. Bend tests were performed on the samples and on unirradiated control samples to secure a measure of the effect of radiation exposure on the physical properties of the material.