Ammonium Nitrate Fuel Blocks

The object of the work described in this report was to determine whether the physical variables inherent in the procedure for loading AN-M7 smoke-pot fuel blocks had any noticeable effect on the observed tendency of the blocks to swell during storage. No relationship was found between consolidation pressure, ram dwell time, or the presence of a cellulose-nitrate disk seal, and the tendency of fuel blocks to swell. There was a correlation between slight swelling and 1 the addition of 2 water to the fuel mixtures prior to consolidation and 2 consolidation of the fuel mixture in one increment instead of two. It was also found that the starter mixture showed signs of swelling, that blocks having a concave top surface swelled, and that fast MIL-STD-545 fuel mixtures showed considerably greater swelling than pure ammonium nitrate blocks. All the minimum fuel blocks used in the experiments swelled after storage. No change in the physical variables inherent in the loading procedure of fuel blocks is capable of completely eliminating the tendency of ammonium nitrate fuel blocks to swell.