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Angular distribution and kinetic-energy spectra of fragments, and cross sections for fission of gold with 68- to 124-Mev C{sup 12} ions have been obtained by observation of the fragments in two types of detectors, gas scintillation chambers and silicon p-n junctions. From the parameters used to fit the angular distributions to the theoretical curves of Halpern and Strutinski, we have obtained the average excitation energy of the fissioning nucleus at the time of fission. This quantity is approximately 25 Mev, which is nearly independent of bombarding energy, suggesting that fission is preceded by the emission of several particles from the compound nucleus. The fission cross section increases from a value of 100 mb at 68 Mev to 1.28 b. at 124 Mev. Over this range of bombarding energies, the total fragment kinetic-energy release rises from 142 {+-} 6 to 146 {+-} 6 Mev. At all bombarding energies, the variation of laboratory-system kinetic energy of the fragments with laboratory-system angle indicates full momentum transfer by the bombarding particle to the fissioning system.

Failure of reactor rear face connectors is a problem at the reactors. The vibration has been studied at H and F Reactors to assist in the development of a permanent replacement for these connectors. Vibration data were otained from rear nozzles, connectors, and crossheaders within the process tube pattern for the following operating conditions: full cold water flow prior to reactor startup, normal operating power level, and during transition from shutdown to normal operating power level. The vibration patterns at 105-F and 105-H were similar in magnitude. Oscillograph data are presented.

A design was developed for leading thermocouples from a high-temperature, pressurized water reactor-coolant system of such integrity that no reactor shutdowns were caused by its use. Using this design, measurements of the fuel-element-cladding temperature and its variation with time were made in three tests on elements clad in type X-8001 aluminum alloy. The following conclusions were reached from the test results: (1) the cladding temperature of a fuel element operated at low heat flux in high bulk-outlet temperature water did not increase with time and was slightly lower than predicted by the Sieder-Tate equation; (2) cladding temperatures of fuel elements operated at high heat flux in either high bulk-inlet or outlet temperature water increased 40 C higher than predicted by the Sieder-Tate equation with initial temperatures equal to the predicted temperatures; and (3) the rate of temperature increase appeared dependent only on fuel-element heat flux and location with respect to the front and rear faces of the reactor.

This report discusses activities from the fuels processing department. Activities described include personnel statistics concerning injuries and accidents; operating plans concerning the N loading activities, 305 test reactor, projection fuel elements; process fuel element testing, and general engineering operations from the department.

Nickel plating on the coolant contacting surfaces of aluminum-jacketed fuel elements is highly attractive for increasing resistance. Potential benefits include a highly corrosion-resistant coating for severe localized conditions, reduction of mechanical damage to fuel element jackets, improved fuel element alignment (by reducing friction between fuel element and process tube ribs) and probably lower overfall surface temperatures to reduction in corrosion product film with improved corrosion resistance, neutron economy might also be realized. For example, substitution of a 0.5 mil thick nickel plate for 15-mils thickness of aluminum jacket would result in no reactivity loss and permit a concomitant increase in uranium volume, or in coolant flow annulus. Attendant problems include providing an adherent continuous plate of uniform thickness and possibly contamination of reactor effluent by radio-nickel-cobalt, and phosphorous and it was found that gross sloughing of the nickel plate had occurred. Development and testing work was carried out to determine the cause and a solution to the Greece problem. Studies were limited to the behavior of chemically-deposited nickel because of the unique capability of the process to deposit a coating of uniform thickness in the 0.1 - 0.2 mils thick range, regardless of the geometry of the plated piece. Based …

In reviewing the data on hydrogen content in the canning baths, the solubility limit of H{sub 2} in Al-Si, and the U-H{sub 2} relationship as was suggested earlier, it appears that the surface H{sub 2} on the core should be less than 0.4 ppm to be below the H{sub 2} concentration level routinely found in the canning baths. What effect low surface H{sub 2} of about 0.4 ppm would have on braze porosity after canning is unknown. However, several years ago (about 1955) some solid cores were vacuum outgassed at MAPO to about 0.5 ppm total H{sub 2} and very little braze porosity resulted.

Preparation of about 1200 g of uranium nitride powder is reported. Experiments indicated that synthesis of mononitride by decomposition of higher nitrides required pro longed heating at high temperature. Chemical analysis of uranium nitride for nitrogen was found to be difficult. Data from analysis of these compounds are tabulated for comparison with calculated composition. Sintering studies of uranium mononitride continued during the report period. Work on uranium silicide formation from the elements without quenching was continued, and effects of crucible material on the synthesis of the material were investigated. (For preceding period see ORC-254.) (J.R.D.)

High-energy studies of the (p, 2p) reaction in Zn{sup 68} and Fe{sup 57} are being carried out. The excitation functions for the reactions, Zn{sup 68}(p, 2p)Cu{sup 67} and Fe{sup 57} (p, 2p)Mn{sup 56} are being measured from 400 Mev to 6.2 Bev. Preliminary results are shown in Table 1. The cross sections are calculated on the basis of a 10.7-mb cross section for the Al{sup 27} (p, 3pn)Na{sup 24} reaction used to monitor the proton beam. The yield of Mn{sup 52} from proton bombardments of natural iron is found to be approximately constant at 7 mb over the energy region 400 Mev to 4.0 Bev. Similarly, the yields of Cu{sup 61} and Cu{sup 64} from proton bombardment of natural zinc are constant at 17 mb and 13 mb, respectively, over the same energy region. Experiments are being carried out in an attempt to measure the cross section for the reaction Zn{sup 68} ({pi}{sup +}, {pi}{sup +}p)Cu{sup 67}, using 310-Mev {pi}{sup +} produced at the 184-inch cyclotron. The meson beam, which is produced by 720-Mev protons incident on copper, has an intensity of about 10{sup 6} {pi}{sup +} per min over a 3-in.-diameter circle. The total induced activity of Cu{sup 67} …

As a result of repeated epidemic losses of brazed cathodes at GEXF, the engineering work necessary to determine the best brazing cycle and the controls necessary to insure reproducibility and high yields in the future was carried out by means of EN-297. Included are the procedures used and the tests made to verify the conclusions drawn and the recommendations made.