Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na{sub 2}SO{sub 4}/H{sub 2}SO{sub 4} anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. …

The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor. This effort will consist of a series of up to 20 parametric tests in a 20 MMBtu/hr slagging, air cooled, cyclone combustor. During the present reporting period, this combustor was in the final stages of re-installation in a new facility in Philadelphia, PA following its relocation from a test facility in Williamsport, PA. Initial shakedown test on this new combustor facility began in December 1995, at the end of the present quarterly reporting period. The shakedown tests will continue through the next quarterly reporting period in the first three months of calendar year 1996. SO{sub 2} is controlled by injecting calcium oxide based sorbents into the combustor to react with sulfur emitted during combustion. The spent sorbent is dissolved in the slag and removed with it, thereby encapsulating the sulfur in slag. Part of the sorbent exits the combustor with the combustion products into the boiler where it can react with the sulfur. The primary objective of the present tests is to maximize the degree of sulfur retention in the slag. All spent sorbent not reporting …