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Decomposition of Water at High Temperatures and Pressures Under Reactor Irradiation.

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The investigation of the high temperature and pressure dissociation of water under irradiation was undertaken by the Power Pile Division of Oak Ridge National Laboratory in an effort to determine the degree of importance of the phenomenon with respect to the design of a high temperature water cooled power reactor. Theory and past experimentation indicate that net steady state dissociation is determined by the rates of the dissociation and recombination reactions under the imposed conditions, the dissociation rate being essentially a function of flux and the recombination rate essentially a function of temperature. A static electrically heated autoclave and associated temperature controlling, pressure recording, filling, purging and sampling apparatus was constructed and the autoclave installed in a test hole of the X-10 reactor under an approximate thermal flux of 5 x 10exp 11 neutroncm2 - sec. Two data runs were made, one at 3500 F and one at 4500 F, on water with a gas phase of saturated steam. Neither run showed any significant increase in pressure throughout, and analyses of the water phase indicated very slight gas formation easily attributed to autoclave corrosion. The conclusion was reached that, under the conditions of flux and temperature of these experiments, the recombination rate is considerably higher than the dissociation rate. Several attempts were made to determine whether or not gaseous hydrogen and oxygen added to the gas phase would dissolve and enter into the recombination reaction, but inconsistent leaks in the system valving developed, rendering the data worthless. At present the valving is being rebuilt, and these experiments will be repeated.

Subject Categories:

  • Inorganic Chemistry
  • Fission Reactor Materials

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