The three isomeric (5-phenyl-2-oxazolyl)pyridines have been shown to be sensitive fluorescent pH indicators which show a pronounced change to increased visible fluorescence as the pH is lowered. Absorption and fluorescence spectral data and pK values are given. Selective excitation of fluorescence from the conjugate acid in the presence of the free base was found possible. The sensitivity of the 4-isomer was demonstrated to be adequate for determining the small amounts of acid produced in certain chemical dosimeter systems. (auth)

A calculation was made, using the Monte Carlo method, to determine the transmission of neutrons through blocks of deuterium oxide at cryogenic temperatures. Coinputations were made for cylinders of D/sub 2/O ice at four degrees absolute, 60 and 75 centimeters long, and 45 centimeters in diameter. The incident neutrons impinged uniformly over one flat surface with an incident intensity proportional to the cosine of the angle between the direction of motion of the particles and the normal to the surface. Their energy distribution was a Maxwellian at a temperature of 300 deg absolute. In the initial trials of this calculation, it was fouad that more than 90% of the incident neutrons were reflected out of the surface of the block at which they had entered. Since in actual use the block will be placed against the thermal column of a reactor, it was clear that the treatment or the incident face as a free surface was not realistic. Such a highly reflecting system would have a marked effect on the flux in the source region, and the material of the thermal column, further, would reflect most of these neutrons back into the D/sub 2/O ice. In order to more adequately …

The ultimate achievement of a research and development program at Sandia. Corporation, as at any other AFX or DOD project, is the physical design of a component or weapon system of high reliability. The design accomplishment is initially established when the basic drawings and specifications are released for production. These drawings and specifications are often based on engineering evaluations of bread- .board and early so-called & quot;gold plated prototypes. However, the design accomplishment is not completed until the item is manufactured by production tools and performs satisfactorily, meeting all the requirements specified in the engineering and manufacturing information. It is only at this stage that we have initial assurance that we may proceed with quantity production. This transition from essentially handmade prototypes to a production-tooled reliable product is a crucial one in any design development program, but it is especially as when the end product is complex and extremely high reliability is required.

Tbe true stress--true strain curves and modulus of elasticity were determined on a uranium--10 wt. % molybdenum alloy at room temperature and at 250, 500, were conducted in a liquid bath to minimize oxidation effects. The test results indicated that the strength properties and modulus of elasticity of the uranium-10 wt. % molybdenum alloy decreased with increasing temperature from room temperature to 1250 d F. Up to 500 d F, the true stress values increased with increasing true strain from the start of loading until the specimens failed. At higher temperatures, however, the true stress reached a maximum at an intermediate strain value before rupture, probably because of a tendency of the alloy to creep at a faster rate than the applied rate of strain. (auth)

Creep properties of 15% cold-worked Zircaloy-2 at elevated temperatures sre presented. Work has continued on extrusion claddings flat plates utilizing the right-angle tooling. Study of uranium oxide structures has continued with emphasis being placed on determinng residule contents in UO/sub 2/. Four melting experiments were made using pure uranium dingot stock to meassure the total quantity of gas evolution occuring at various controlled temperature levels in the 2000 to presented in the Zr-1 wt. % uranium hydride system. Corrosion test results ane presented for gamma-phase urranium alloys. A program is presented that has the objective of obtaining fatigue information on Inconel along with variables of temperature, stress, strain, time, and cyclic frequency. Several experiments were performed to attempt to produce dense and homogoeneous bodies of UO/sub 2/ and La/sub 2/O/sub 3/. The electrical properties of UO/sub 2/-metal oxide systems sne given A study of phase relationships existing between the intermetallic phases of the U-Zr and U-Mo alloys is presented A solidstate study of the ternary system U-N-C is presented. (For preeeding periodd see BMI-1238.) (W.L.H.)

Thermal-conductivity and electrical-resistivity measurements were made on U-1.5 wt,% Zr, encapsulated in Zircaloy-2 with a NaK thermal bond. Data are presented on thermal conductivity measurements made on UO/sub2/ specimens. A method of sink-float measurement to identify factors affecting irradiation- induced volume changes in graphite was continued. The stress-rupture and creep properties of 15% cold-worked Zircaloy-2 are being investigated in the 290 to 400 deg C temperature range in vacuum. High-purity single crystals of Mo are being prepared for irradiation-damage studies. A feasibility study of the neutron- activation method for the elemental analysis of portland cement was completed and preliminary experiments were initiated. The chemical analyses of irradiated and nonirradiated cetane, stearic acid, and the corresponding urea complexes were continued. A study of the mechanisms by which U solidifies in a cylindrical mold is being made. Coatings of Mo compounds on Croloy 2 1/4 were studied as potential protective coatings against liquid Bi. Work on the study of valence effects of oxide additions to UO/sub 2/ indicates that additions of Y/sub 6/O/sub 3/ are better stabilizers than La/sub 2/O/sub 3/ in 3000 deg F air. Measurements of hydrogen-absorption isotherms for the Zr-25 wt.% U alloy were made. An investigation was made …

The creep properties of 16% cold-worked Zircaloy-2 are being evaluated over the 232 to 299 deg C temperature range. helium density measurements were made on samples of UO/sub 2/, and the results are tabulated. Phase boundaries in the Zr--1 wt.% U alloy system were studied. Results of 168-hr corrosion testing of U--Nb and U--Mo alloys in 680 deg F water are given. The reaction between U and water or water vapor is being studied at temperatures ranging up to 200 deg C. Data are given on the hardness and fabricability of some new Nb alloys along with oxdiation data for Nb and Nb alloys in dry air at 1000 to 1200 deg C. The ternary system uranium --nitrogen --carbon is being studied to determine the stability of solid-solution phases of uranium carbides and nitrides, and to investigate the possible existence of ternary phases. Creep data are given for tantalum during exposure to high-temperature sodium. (W.L.H.)

A preliminary study of the volatility behavior of molybdenum indicated that MoF/sub 5/ was converted to MoF/sub 6/ by F/sub 2/; MoF/sub 6/ and Tc fluoride are absorbed on NaF at 100; technetium fluoride is more strongly held than molybdenum fluoride on NaF; MoF/sub 6/ may not be completely trapped by a dry ice trap. The behavior of volatile fission product fluorides was such that (a) Ru and Nb fluorides were volatile from fused salts during fluorination, (b) Mo and technetium were not volatile during hydrofluorination but were in excess F/ sub 2/> 100 deg C(auth).

The combined attack of HNO/sub 3/ and HNO/sub 2/ on TBP-kerosene solvents used in the Purex Process produces degradation products that cause abnormal quantities of zirconium to be extracted along with the plutonium and uranium and thus limits the decontamination. (auth)

Results are given from studies on: mechanical properties of Zircaloy-2; preparation of Al--U alloys; effects of N, Ca, Zr, and Mo on electrical properties of UO/sub 2/; effect of chloride, fluoride, and sulfate contamination on corrosion of type 304ELC stainless steel in boiling HNO/sub 3/; density of Mallinckrodt slag and MgF/sub 2/-base materials; development of gamma-phase U alloys; preparation of U--Nb alloys; oxidation of Nb and Nb alloys in dry air at 1000 and 1200 deg C; thermal expansion of UBe/sub 13/ and UC; phases and compositions in C --N--U system; creep of arc-cast Ta during exposure to high- temperature Nas pressure bonding of PWR fuel platess evaluation of UC as reactor fuels and fabrication of UO/sub 2/ fuel pellets for NMSR loop tests. (For preceding period see BMI-1259.) (T.R.H.)

Measurements of thermal conductivity and electrical resistivity were continued on irradiated specimens of UO/sub 2/-clad in Zircaloy-2 with NaK as the heat-transfer medium. The creep strength of 0.15% cold-worked Zircaloy-2 is being determined at elevated temperatures. Work continued on the development of highstrength corrosion-resistant Zr alloys. Research to develop a method of sink- float density measarements to identify factors affecting irradiation-induced volume changes in graphite was continued. Single crystals of high-purity Mo are being prepared for irradiation damage studies. Casting methods are presented for Al--U alloys. Time-temperature relationships are being studied during the solidification of small cylindrical U castings to improve the quality of fabricated U fuel slugs. Methods for preparing a thin protective coating of Mo on Croloy are being investigated. Research indicates that in a binary system of UO/sub 2/-- La/sub 2/O/sub 3/ 60 wt.% La/sub 2/O/sub 3/ is required to form a stoichiometric structure after oxidation. Investigations of the hydrides of U- Zr alloy for possible use in gas-cooled reactors were continued. An irradiation- damage program on type 347 stainless steel was undertaken to study the changes in physical properties that are caused by continued exposure to a fast-neutron flux up to 3 x 10/sup 15/ nvt …

Data are given on: creep propenties of 15% coldworked Zircaloy-2; the liquidus in Al-U; effect of chloride on corrosion of type 304 ELC stainless steel; corrosion testing of stainless steels, Ti 75A lead, and rigid PVC as container materials for HNO/sub 3/-recovery process; viscosities of MgF/sub 2/ and MgF/sub 2/-MgO slags; phase boundaries in the U-Zr-H system; oxidation of Nb, Nb-W, and Nb-V alloys in dry air at 1000 and 1200 deg C; nonoxidizing properties of UO/sub 2/- La/sub 2/O/sub 3/ and UO/sub 2/-Sc/sub 2/O/sub 3/; study of bounding fuedamentals; hydrogen adsorotion by Nb; diffusion of H in ZrH/sub 4/; reflector controlled heterogeneous boiling reactor; pressure bonding of Zircaloy- 2-clad compartmented UO/sub 2/ fuel plates for PWR; and evaluation of UC as reactor fuel. (For preceding period see BMI-1247.) (T.R.H.)