The fixation of aqueous radioactive wastes in a stable solid media by means of calcination has been the subject of considerable research and development effort. Several methods of doing this on a continuous basis have been devised and a few have been demonstrated to be feasible for the handling of non-radioactive or low activity simulated wastes. Currently an investigation of calcination by means of radiant-heat spray drying is being carried on by the Chemical Research Operation of the Hanford Laboratories Operation. The process consists of atomizing the liquid to be treated into the top of a cylindrical column, the walls of which are maintained at a high temperature. The resultant suspension of droplets in the water vapor formed by evaporation passes through successive zones of drying, calcination, possible chemical reaction or melting, and partial cooling as it proceeds down the tower. Separation of the resultant solids, steams, and uncondensable gas is made by conventional methods.

Previously, W. S. Figg and T. W. Ambrose (HW-51767 Rev) have investigated the problem of flow decay following electrical power loss to the PRTR primary coolant pumps. However, since the time of their study many reactor piping changes have been made in the design; therefore, it has become advisable to re-examine the problem incorporating these changes.

PuO2-UO2 Irradiation Capsules. Four capsules of Zircaloy-clad, sintered PuO2-UO2 mixed crystal oxides in a UO2 matrix are awaiting irradiation in the NTR.

Whenever fissile materials are handled in significant quantities such as in fuel element fabrication, separation processes, or in exponential and/or critical experiments a potential criticality hazard exists. The usual procedure which is followed by those persons conducting critical mass experiments is to either place the potential reactor in a heavily shielded cell or to conduct the experiments remotely in which case distance provides a measure of safety in the event of an unscheduled radiation outburst. In considering potential critically incidents, especially for the personnel not specifically engaged in critical mass studies, it is very likely that at the time of the incident neither the conditions of shielding nor distance will prevail for the personnel involved.

It is anticipated that neptunium will be recovered in the Purex process by solvent extraction or ion exchange methods as a nitric acid solution of greater than 0.1 g. Np/1 and containing varying amounts of fission products, plutonium, uranium, and thorium, including Th234 (UX1). At the present time this solution is thermally concentrated in the Purex L-cell package to several grams of neptunium per liter. In this operation the solution is contaminated rather badly with plutonium and stainless steel corrosion products. The present specifications are for the neptunium final product to contain less than 0.1 weight percent plutonium, to be relatively free of gross metallic contaminates, and to be low enough in fission product game activity and Th234-Pa234 (UX1-UX2) beta activity to be handled without resorting to remote techniques.

In solvent extraction purification processes such as are used at Hanford, the fuel elements or "slugs" from the reactor containing uranium, plutonium, and fission products are dissolved in nitric acid, adjusted to the required feed composition, and pumped to the solvent extraction columns. Figure 1 in a schematic diagram of such a solvent extraction process. In the A column, the uranium and the plutonium are extracted into an organic phase while the bulk of the fission products remain in the aqueous phase and leave as waste with the column raffinate.

Nuclear safety in the dissolution of irradiated 0.95 U235 enriched fuel has been investigated. In particular, critical conditions of fuel of this enrichment in a 52-inch diameter dissolver crib were studied. Since a crib this size is not safe by geometry, dissolution procedures as well as maximum safe batch sizes were analyzed. Uranium-water lattices are normally studied in systems in which rods are uniformly dispersed in the moderator. The results of such a study for 1.34-inch diameter solid rods as well as I. and E. fuel having a 1.37-inch O.D. by a 0.48-inch I.D. have already reported.

Examination of Al- 1.65w/o Pu and Al- 12 w/o Si- 1.65 w/o Pu capsules irradiated 55- 60% burnout of the plutonium atoms revealed a 1.4% volume increase and no apparent microstructural changes. A four rod cluster containing Al-8 w/o Pu and Al-12 w/o Si-8 w/o Pu alloy cores is currently under irradiation in Loop 3 of KE Reactor at a water temperature of approximately 230C. A second cluster has been fabricated an is scheduled for charging late in 1958. Two seven-rod clusters for irradiation in KER are also being fabricated.

The purpose of this procedure is to present a detailed, chronological presentation of the preliminary decontamination and post decontamination steps necessary to fulfill the requirements of the Production Test Authorization IP-239-N. The procedure attempts to present the required operation in sufficient detail to successfully accomplish the intent of the test. Certain procedures involve operations of a standard nature and have not been elaborated upon to any great extent, as it is expected that the reactor operations and radiation monitoring personnel will implement these instructions according to standard operating procedures.

The monocarbide and the mononitride of uranium are potentially useful ceramic nuclear fuel materials. This paper reports the results of exploratory investigations of the reactions of uranium monocarbide and uranium mononitride with boiling water. Uranium dioxide, chemically stable in deoxygenated boiling water, was used as a control.

Judging scratch depth or surface roughness by unaided visual inspection under controlled conditions, while rapid and popular, is not quantitative. Comparison methods improve reproducibility but are generally not applicable to evaluation of depths of single widely spaced scratches. Stylus-type contour recorders yield valuable scratch contour data but may themselves plow through soft materials and fine details. Depth measuring microscopes are particularly applicable to measurement of pinhole depth but do not graphically reveal profiles and provide only a small field of view. The comparatively large field of view and graphic display of contour provided by profile microscopes make them particularly suitable for evaluation scratch depth as well as surface roughness. A HAPO-constructed instrument has demonstrated an accuracy of +/- 50 micro inches in the range of 50 to 15,000 micro-inches scratch depth. It is a pocket-sized, portable, and can be used on horizontal and vertical surfaces by untrained persons with only brief instruction.