A exploratory study was made of a polarographic technique in which an alternating sine or square-wave potential is superimposed upon the applied d.c. potential of the polarographic scan. Recording of the a.c. component of the polarographic current results in derivative-type waves. It was shown that the technique yields greater sensitivity and greater selectivity than normal polarographic technique.

Gradual corrosion and mechanical wear of equipment over a period of years has affected the seals and gasketing of the electric pot calcining equipment in the 224-U Building Cell E to such an extent that the desirable vacuum cannot be maintained in the pots. Air contamination has been gradually increasing, and this, together with a lowering of the mask working limits, has made it necessary to require personnel to wear assault masks continuously. Indications are that, with the increased production now required, the level of air contamination will continue to rise unless measures are taken to prevent it. The Manufacturing Department has requested that a project be established to reduce the contamination level. Several items of improvement are listed for consideration including, in general, the electric pot agitation and sealing, semi-automatic pot unloaders, cell ventilation and air locks, and the nitric acid off-gas system and stacks. Because of the urgency of improving the conditions, the project, at first, is to provide for immediate improvements for the electrical pot agitation, the pot cover leakage, and the nitric acid off-gas system and stack. Additional study will be required to determine the extent of the ventilation and semi-automatic unloading improvements required.

This twenty-fifth quarterly report of the research and development activities of the Radiological Sciences Department, Hanford Atomic Products operation, as before, includes some items charged to control but included for general interest. The previous report of this series was numbered: HW-39624, October 11, 1955. Progress is reported in the following studies: a radiobiological-ecological survey of the Columbia River; the toxic effects of continuous low-level exposure to I¹³¹ in pigs; Pu metabolism in miniature pigs and rats; the tissue distribution and retention of Ru¹⁰⁶ and Cs in rats and mice; the radiosensitivity of the intestine of rats; the pulmonary absorption of radioactive particles and the pathological effects of such particles in the lungs of mice; the uptake of I¹³¹ and other fission products from the soil and from air by plants; determinations of the relative biological effectiveness for yeast cells of Po²¹⁰ alpha particles and P³² beta particles; the development of chemical and radiological monitoring methods; the separation of fission products from waste streams; and improvements in instruments for monitoring and low-level radiation counting. The status of the research programs of the department is reviewed.

Limitations on the maximum temperature of the pile moderator have been imposed to prevent or control the gasification reaction of the graphite stack with the pile gas atmosphere. An uncontrolled reaction would cause a loss of structural strength, density, and thermal conductivity and would thus result in an unnecessary shortening of the effective operating life of the HAPO piles. Numerous studies have been made to define the rates of reaction of the pile stack with various components of the pile gas and the influence on these rates of various pile operating conditions. Based on these studies, maximum graphite temperature has been so restricted that after 10 years of pile operation the graphic stack has sustained less than 1% oxidation (based on recent experimental data). As pile power levels increased, the maximum graphite temperature has also increased and will increase still more as present and future power level programs are completed. In order to evaluate the effect on the graphite stack of the present programs, and to some extent determine the feasibility of future programs, a more realistic approach to the question of structural integrity and oxidation versus pile life is necessary. It is the purpose of this report to summarize …