The purpose of this investigation was to determine the effects of mild pressures and hydrogen concentrations on the formation of ammonia by slow neutron irradiation of gaseous hydrogen-nitrogen systems. A secondary purpose of this investigation was to determine the effects of neutron irradiation on ammonia synthesis. Apparatus consisted of two parallel reaction tubes identical except that one was under an average neutron flux of 700 neutrons per square centimeter-second in a paraffin howitzer. The reaction tubes were of pyrex with inside diameter of two inches and length of four feet. Ammonia produced was absorbed in ten-milliliter portions of very dilute hydrochloric acid, and the rinsings from the tube walls were added to the sample. Analyses of the samples were made with Nessler’s reagent and a colorimeter. Tests were performed at pressures of 3.0, 4.0, and 5.0 atmospheres and at hydrogen-nitrogen molar ratios of 3.0 and 6.0. Reaction time was 24 hours, and average total flux was 6.05 x 10⁷ neutrons per square centimeter. It was found that the amount of ammonia formed in the irradiated reaction tube was from 4 percent to 73 percent greater than the amount formed without irradiation, the results for testing the effects of ratio of reactants and of pressure were too scattered to permit any valid conclusions, and that ammonia synthesis under neutron irradiation is worthy of further study as a possible industrial process. / Master of Science