1. ANL should evaluate the potential impact of the higher salt content of the Mark-V HTER product on the performance of the cathode processor.

  2. ANL should evaluate the effects of cathode surface roughness on the adhesion of the uranium deposit; other materials or metallic coatings that might reduce adhesion of uranium on the ACM cathode should be considered.

Cathode Processor and Casting Furnace Unit

Efforts continued at ANL-W to evaluate the performance of both the cathode processor and the casting furnace unit processes. Reduction of the pressure in the cathode processor to about 1 torr reduced the operating temperature from 1225 °C to about 800 °C. This lower pressure also resulted in more efficient distillation of fission products from the uranium.

ANL-W is working with an outside vendor to produce larger beryllia crucibles, which are required because of the marginal performance of the baseline material in the crucible when uranium, process salt, and cadmium are present simultaneously in the cathode processor.

As of October 1998, 30 batches of uranium and 7 batches of cladding hulls had been processed through the cathode processor from irradiated EBR-II fuel.


Metal Waste Form Testing and Plans

ANL's metal waste form (MWF) test plan calls for a total of 856 tests. The MWF test plan consists of attribute tests, characterization tests, accelerated tests, and service condition tests. A large number of the samples that will be tested differ only very slightly in minor alloying elements.

Metal Waste Form Release Rate

The object of this work is to develop a model of the radioisotope release rate for the stainless steel MWF. A number of potential degradation mechanisms were discussed in the committee's meetings at ANL-W and ANL-E.

  1. Since no corrosive attack on the MWF has been observed in the immersion tests conducted thus far, it is unlikely that tests under mild conditions will yield any additional information. A general observation has been the lack of information from these tests under mild conditions. As a result, it is questionable whether the large number of MWF tests (856) is necessary.

  2. The proposed study of crevice corrosion requires careful design of an artificial crevice with consideration of the proposed application of the alloys used in the MWF.

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