Second and third tests were conducted on an expansion bellows and Zircaloy-stainless steel transition joint assembly, duplicating that used in the core-pressure vessel assembly of the HRT. The assembly was exposed for 1140 hours in the second test and and 167 hours in the third to a solution containing 0.04m UO2SO4, 0.02m H2SO4, and 0.005m CuSO4 in a 100A dynamic corrosion loop under conditions simulating reactor startup, shutdown, and steady-state operation. Results indicated that the transition joint assembly as tested was mechanically sound and leak-tight. Pit-type corrosion continued on the expansion bellows where the upper retaining tangent contacts the bellows. Results are included of specimens exposed to the circulation solution during transition joint and bellows test.

Data are presented for all toroid runs which circulated aqueous thorium oxide slurries between Aug, 1054, and October, 1956. In addition, a tabulation of the properties of numerous thoria preparations is presented.

The distillation method (Argonne Sampler) for the analysis of sodium oxide in NaK was used to calibrate a plug indicator. The description of the equipment, procedure, and experiences with the Argonne Samplers are presented in great detail to aid future users of this method. Although this method is not very precise, it has been thoroughly checked out and is recommended as a standard means for sampling and analysis for oxide in liquid metal systems. (auth)

The assembly of a second thorium oxide slurry corrosion test facility, loop BS, has been completed and 2010 hr of operation on slurry have been logged. This second test loop has proved satisfactory from an .operational standpoint. Corrosion data and operational observations are given for six thorium oxide slurry runs made at 300 C in 100A pump loops BS and CS. A new development model of the rotator for an in-pile slurry toroid is described.

In conjunction with Gas-Cooled Reactor heat-transfer studies, local and mean heat-transfer factors are predicted from the heat transfer-mass transfer analogy using subliming naphthalene in air. Experimentation was conducted on 1-in.-dis septafoil rods in a 4-in. -dis flow channel with rod center-to center spacings of 1.10, 1.25, and 1.40 in. at a Reynolds modulus of approximately 60,000. Ratios of local mass transfer to mean mass transfer for a given rod vary as much as from 0.7 to 1.3 (outer rod, 1.10-in. spacings). Mean values of the mass-transfer factor are, in general, above that predicted by the correlation j-0.023 NRe^-0.2; as much as 46% got the outer rod t 1.25-in. spacing. The data indicate that for maximum mass transfer and minimum variation of the mass-transfer factor, an optimum rod spacing exists; the best observes is at 1.40-in.

An approximation is derived for the time constant which characterizes the rate of energy loss of fast ions moving through a plasma. Using particle and energy-balance equations a simple approximate criterion is derived for the estimation of the importance of energy degradation during plasma buildup in a DCX type machine. Next, there is derived the steady-state ion energy distribution for a case in which energy losses are to electrons at a given temperature and particle losses are by charge exchange. The distribution function is used to compute loss rate, upper critical current, ionization rate, and other functions of interest. Quantitative application is made to DCX-2 under various conditions of operation of carbon and deuterium arcs.

The development of nuclear reactors and other nuclear particle sources has given the analyst a new analysis method which can be successfully applied to the determination of microgram and submicrogram quantities of many elements. Known as "radioactivation analysis", this method is one in which an "activation" by some type of nuclear reaction is used to produce a radioactive isotope of the element to be determined. Since this radioisotope decays with its own characteristic radiations and half-life, it is possible to make radioactivation analysis a very specific analysis. Chemical separations of the radioisotope are employed whenever necessary and its radioactivity measured by some type of radiation counter.

The steady-state radial and axial temperature profiles of an E. G. C. R. 5 1/2" O. D. through tube are determined for the test condition of an attemperated fuel assembly operating at 1500 KW in the loop. The profiles are determined for the case of the central control rod fully inserted and bank insertion to 62 inches (Δk = 0.025). The data are presented in the form of tables and curves.

The pneumatic temperature probe (PIM) is a device for measuring gas temperatures by utilizing the dependency of the flow of gases through a restriction on the temperature and pressure conditions. The determination is made by measuring critical mass flow across a restrictive element such as a nozzle and by knowing the upstream pressure and other variables pertinent to the critical flow equation, computing the temperature at the entrance to the restrictive element. In practice it has been found useful to use two critical flow nozzles in series and measure the ratio of the pressures at the nozzle inlets, together with the temperature at the downstream nozzle. The limitations of present thermocouple materials for long term use at elevated temperatures makes resort to this device attractive on many installations.