Water treatment systems for preparing and maintaining high purity water in out-of-reactor or in-reactor test oops are becoming increasingly important. In out0of-reactor experiments the presence of ionic impurities in the water has a marked influence on film formation and corrosion rates. It is therefore , imperative that these impurities be maintained at the lower practical concentration.

Ceramic insulated, stainless steel sheathed thermocouples have been used to monitor temperatures of encapsulated uranium specimens, both in-reactor and out-of-reactor. No operational difficulties are encountered at low temperatures, but at a temperature of 700 C or greater, a eutectic is formed between uranium and iron. This reaction destroys protective sheath and results in thermocouple failure. A typical example of the phenomenon has been reported by J.W. Geffard of the Fuels Development Operation. Hanford Laboratories. Tantalum was suggested as a barrier between these metals and an evaluation of this system was made at 500 C.

A study of the nuclear safety in the storage and transportation of PRTR fuel elements has been made. This study was based on 7-rod clusters of plutonium-aluminum allow fuel elements containing 1.8 per cent Pu by weight. Each cluster is 7 feet 4 inches in length and contains 270 grams plutonium. Drawings of the "New Fuel Storage Pit" (H-3-11030) have been reviewed for nuclear safety. Nuclear safety criteria for the design of a lead shielded fuel transfer cask as well as criteria for the storage of these fuel elements outside the facilities mentioned in the above drawings have also been reviewed. For water moderated systems, a homogeneous model of plutonium, aluminum, and water was used t evaluate the critical parameters. These results should be conservative. At the conclusion of an experimental program to determine criticality parameters of PU-Al alloys in light water, a theoretical approach will be developed to calculate such criticality parameters.

Two water quality control labs are being provided for the the NPR. One, a "cold" lab, is located in the183 Building adjacent to the control room. Its primary purpose is to provide facilities for quality control of the output of the filter plant and the demineralizer plant. The other, a "hot" lab, is located in the 190 Building. Its primary purpose is to provide facilities for the quality control of the primary and secondary coolants, and the moderator coolant.

Through the years, considerable effort has been expended in studies of the explosive reactions sometimes observed in the dissolution of uranium-zirconium alloys in nitric acid. It has been shown (1) that such reactions result from the rapid oxidation of finely dived solids released by the preferential dissolution of the metallic matrix. The explosive portion of such solids has been identifies (1) as an intermetallic compound with the approximate composition UZr2. This compound, referred to as the epsilon phase in previous work, has more recently (2) been termed the delta phase. The latter designation will be employed here.

Design Test Request PR-20 Calandria Characteristics, outlined the need for experimental data concerning the performance of the calandria under transient conditions. Test data was required to confirm that the moderator dump system would drop the level the required 24 inches in less than one second. The original calandria dump chamber design was modified until the criteria was met. This information is recorded in HW-58333, Interim Report, Design Test PR-20, Calandria Characteristics, which lists the drop for the first 24 inches only.

The majority of two-phase flow problems involving equations of state are solved by use of point-wise utilization steam table values. In this manner, problems involving the use of the various flow equations of continuity, momentum and energy are generally forced into iterative solutions. Considerable effort towards the development of an analytical expression for the state equation seems indicated so as to simplify the analysis of two-phase problems, particularly apparent in the analysis of systems undergoing phase transformation as demonstrated by the significant difference between simple theory and experimental critical flow determinations. The assumption of homogeneous, equilibrium mixture is indicated as a first attack upon the problem.

This is the sixth in a series of interim reports describing various phases of the study of fuel element rupture kinetics and mechanisms. Previous reports issued are: No. 1- Experimental Methods and Procedures, HW-61378, No. 2- Coextruded Rod Elements with Pinhole Defects, HW-61379, No. 3 - Mechanism of the Uranium-Water Reaction, HW - 61799, No. 4 Coextruded Tube Elements with Pinhole Defects and Various Annular Spacings, HW- 62348, No. 5- Comparison of In-Reactor and Ex-Reactor Ruptures, HW-62766. This work is being done in cooperation with the Fuel Element Design Operation of the Hanford Laboratories Operation. J. W. Goffard has been particularly helpful in supplying samples and useful discussions of the results.