Structural evaluations of the upper head of the EGCR pressure vessel were made. The configuration throughout the cluster region in the vessel was found to be structurally adequate. The primary and primary-plus-secondary stress intensities for the burst-slug detection and gas outlet nozzles were found to be within the allowable limits. However, the complete design evaluations of these units cannot be made until the temperature distributions are known. (auth)

BS> The use of titanium getter pumping for large vacuum systems is described. Techniques were developed which give sorption rates approaching the maximum theoretically possible for many of the chemically active gases. A simple method of determining sticking fractions is descrnkbed. Sticking fractions for hydrogen, deuterium, oxygen, nitrogen, carbon nknonoxnkde, carbon dioxide, and methane are given for various films. The capacity and sorption characteristics for these films are shown. Simple and reliable resistance-heated titanium evapdorators are described. lt was demonstrated that the pumping methods described provide outstanding performance and are both reliable and practical. (auth)

A dissolver design was demonstrated on a laboratory scale for the electrolytic dissolution of nuclear fuels. Simplified electrodes are used which need not touch the fuel pieces, thus avoiding the usual problems of achieving adequate electrical contact between the fuel and the anode basket. Because a series of electrolytic cells are formed along the length of the dissolver, current efficiency is enormously increased; this technique allows for the use of higher voltage and much lower current than is presently considered essential in plant-scale electrolytic dissolution. (auth)

At the end of September l961, construction of the Heavy Water Components Test Reactor was about 90% complete. Thirty-two compacted tubes of crushed, fused uranium oxide in Zircaloy sheaths were fabricated for irradiation tests and destructive evaluation. lrradiation tests of the tubes were started in the Vallecitos Boiling Water Reactor and at Savannah River. The fabrication process for the tubes included steps designed to exclude hydrogenous material from the oxide cores, thereby eliminating the probable cause of sheath failures in previous irradiations. Additional experimental data on heat transfer burnout of tubes in subcooled water at pressures of about 100 to 1000 psi showed that the burnout heat flux is not affected significantiy by pressure in this range. The data were correlated in terms of water velocity and subcooling. (auth)

Some of the factors affecting the counting rate achieved by a neutron chopper spectrometer are investigated. It is shown that in a chopper of optimum design the counting rate per channel at any given energy is proportional both to the slit width and to the square of the resolution in mu sec/m, as well as to the cutoff velocity vc of the rotor; this last is because a larger number of bursts per second become possible as vc is increased. For an idealized cutoff function, it is shown that the total running time for measuring a spectrum is minimum when the ratio of cutoff velocity to peripheral velocity of the rotor is such that approximately 1.67 runs per energy decade are required; this means that the chopper speed and the time-channel width are changed by a factor of two from one run to the next. (auth)

The Idaho Chemical Processing Plant did not operate on fuel recovery during this period, due to extensive renovation and modiflcation of facilities. Potasslum fluoride was found to be an undesirable additive to the barium precipitating agent used in formation of barium fluozirconate, because of precipitation and loss of uranium, although essentially complete precipitation of zirconium was achieved. Addition of hydrofluoric acid with barium precipitant, to achieve a fluoride/zirconium mole ratio of 5.5, was found to give a total zirconium recovery of 05%, including approximately 10% recovered after concentration of the supernate from the original precipitation. Removal of 97% of the zirconium and fluoride from zirconium -uranium dissolver solutions was achieved by precipitation with two moles of sodium formate per mole of zirconium. Uranium was readily recovered from the concentrated filtrate and wash solution by TBP extraction. The preparation and characterization of zirconium nitrate dibutylphosphate are described, and the solubility in Amsco was found to be similar to that of the uranlum dibutylphosphate complex (2 to 4 x 10/sup -5/ M). Stability studies indicated very little, if any, oxidation of ferrous to ferric iron ln a normal raffinate environment, and ferrous iron has a very low molar extinction coefficsent (0.8) compared …

An investigation is reported of the effect of several oxide additives on the densification of UO/sub 2/-ThO/sub 2/ compositions in which U/sub 3/O/sub 6/ is the initial uranium oxide. Also determined were the effects on densification of variation of the compaction pressure and of the pretreatment of the oxide powders. The validity of results was checked by two forming techniques, dry pressing and extrusion. The results are indicated as follows: additives had an increasing effect on densification with decreasing ThO/sub 2/ content; oxides of transition elements were most effective as additives for im i proving the densification; varying the forming pressure had little effect on densification; precalcination of the initial powders was effective in improving densification; and similar results as above can be achieved with extruded as well as dry-pressed specimens. (auth)

The computer codes CROCK and SHOCK, written to aid power system designers in selecting the minimum weight point for space power plant radiators, are described. CROCK can be used to select the minimum weight design for a system in which the waste cycle heat is radiated directly to space from the condenser, while SHOCK can be used for systems in which the sensible heat lost from a single-phase fluid is radiated. (J.R.D.)

Analogy with optical instruments is used to develop formulas for estimating the counting rate achieved by a neutron time-of-flight system. lnput data consist of the flux at the spectrometer entrance and some of the physical characteristics of the spectrometer. Convenient relations for the comparison of different systems are presented. (auth)

A study was initiated to determine the precision with which surface temperature measurements could be made in irradiation capsules containing ceramic fuel. A thermocouple was considered to be positioned in a longitudinal groove prepared in the uranium oxide and metallurgically bonded to the inside surface of the stainless steel clad. A fuel capsule having a 3/4 inch outside diameter, designed as a segment of the EGCR fuel element, and operating with a heat generation rating of 27,500 Btu/hr/lineal foot was assumed. The finite difference approximation was employed to study both the grounded and the ungrounded types of thermocouple junctions. It was found that when a short dummy lead is positioned axially adjacent to the thermocouple junction deviations of about 118 deg F and 101 deg F are obtained for the grounded and ungrounded junction, respectively; in both cases the indicated temperatures are in excess of the undisturbed clad surface temperatures. (auth)

Under the influence of radiation, the coolant-moderator in an organic moderated reactor slowly decomposes to form high molecular weight polymers (high boilers) and a mixture of gases and light hydrocarbons as waste products. Work carried out on the improvement and subsequent operation of a prototype waste- polymer combustion process is described. Operation of the improved unit employing a vortex'' burner confirmed the feasibility of combustion as a disposal method. It was determined that fuel temperatures of 400 deg F and combustion air temperatures of 300 deg F were required for successful operation. The quantity of ash resulting from the combustion was established to be less than 0.5 wt% of the original polymer. It was determined that the efficiency of the primary dust collector varied from approximately 90 to 99%, and that there was no detectable particulate matter in the gas leaving the absolute filter. Attempted activity-balance calculations proved unsuccessful due to extreme difficulties in measurement of the low-level activty of the stack gas. In an effort to further improve and simplify the process system, preliminary evaluation of another burner was carried out. A cost estimate of the combustion process using the Vortex'' burner was prepared, based on data obtained from …

It is noted that a uniform flat-top beam spill-out cannot be obtained in the Cosmotron by manual control. A servo system is proposed which will control this spill-out by sensing the external beam intensity, and correcting the magnet voltage to keep this intensity constant. This servo must operate through the transfer function of the main ignitron system and the flat-top filter. An analysis of these special transfer functions is presented. (J.R.D.)

Theoretical and experimental studies indicated that the effective permeability coefficient for graphite is lowered by a helium stream in-sweeping through the graphite pores. This phenomenon was considered in the design of HTGR fuel elements. A portion of the helium gas which is drawn into each fuel element as a purge stream may enter through porous wall sections, supplementing the purge gas entering at the top of each fuel element. The purge stream leaves each fuel element through a header system which carries the purge gas to an external fission product trap. The flow rate through the trapping system determines the upper limit of the average in-leakage through the fuel element walls. In the case of the HTGR, a graphite having a helium permeability of 1.1 cm/sup 2//sec at 350 psia and 700 deg F (approximately 0.1 cm/sup 2//sec at 14.7 psia, 70 deg F) would result in 100% of the purge flow entering through the wall sections of the fuel element. A lower permeability graphite, with most of the purge flow entering at the top of the fuel element appeared to be more desirable for maintaining optimum purge flow conditions. (auth)

The addition of alloying elements to base alloys of Th containing 5 and 10 wt% U was investigated with regard to alloy structures and elevated- temperature mechanical properties. The alloys developed possess elevatedtemperature tensile and stress-rupture strengths of essentially twice those associated with binary Th-5 and 10 wt% U alloys at 60O to 800 deg C. The greater strength of these alloys should resuit in improved resistance to radiationinduced swelling at high temperatures. Noticeable improvement in elevated-temperature mechanical properties resulted from the addition of 2 and 5 wt% Zr to the Th-5 and Th-10 wt% U base alloys. Zr was found to be the most effective additive in improving elevated-temperature mechanical properties, although significant improvement was noted with additions of Nb, Mo, C, Al, and Be. Both solidsolution strengthening and dispersion strengthening of the Th --U base alloys were encountered. It was found that a fine intragranular distribution of the secondary U phase improved the mechanical properties of the alloys studied. Structures with optimum properties were produced by careful control of the arc-melting procedure and by solution heat treating at 1350 deg C followed by aging at 850 deg C. Preliminary testing was performed to determine the elevatedtemperature mechanical properties …

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Events in nuclear technology in 1961 are reviewed. The SL-1 incident, operation of the Yankee plant, restarting of the Dresden plant, contributions to the state of water reactor technology, transitions to private industry, dry criticality in EBR-II, startup of Los Alamos Molten Plutonium Reactor Experiment (LAMPRE), successful Tory tests, performance of SNAP reactor tests, and use of radioisotope-powered electric source in Transit IV A are discussed. (M.C.G.)

Boiling and condensing experiments under zero gravity conditions were conducted to investigate the operation of a mercury Rankine cycle power system similar to SNAP I and SNAP II designs. A detailed analysis of the phenomena involved in condensing under various gravity conditions is included. Empirical correlations based on mercury condenser pressure drop data were developed and further interfacial stability tests were made. (J.R.D.)

It is requested that a design be initiated for the primary piping static test. This test is necessary to provide information as to the reliability of the pipe subjected to reactor operating conditions. The test conditions are as follows: temperature - 2000 F (isothermal), pressure effective - 42 psi, and test time - 10,000 hours. It will be necessary to test two sizes of pipe as shown on the preliminary piping layout (2.250-inch O.D. x .095-inch wall and 3 1/2 SCH. 10 pipe). The test specimens shall be jacketed in an inconel containment vessel. The test rig should be similar to the design of the 4-inch pressure vessels (T-1030244). In addition an outer containment vessel constructed of stainless steel must be provided around the clam shell heaters and the inconel containment vessel. This is to provide an inert atmosphere for the inconel vessel. Provisions should be made in the design for a 1/4-inch clad thermocouple. It is planned to use the pipe test as a vehicle for studying experimental Tc's (Cb-Mo and W-W.26% Re).

It is requested that the design be completed for a full-scale fuel element soak test. The test assembly must be designed to permit the fuel element test specimen to be submerged in a lithium bath under a pressure of 60 psi. The maximum temperature of the lithium is to be 2000 F. A total of four test units will be required to complete the test program. Two specimens will be exposed to a thermal cycle between 2000 F and 1400 F with the remaining two specimens being exposed to a thermal cycle between 2000 F and 1000 F. Heating will be done at the rate of 200 F/hour preceded by a 150 hour soak at 2000 F. Heat will be supplied by clam-shell type heaters. The test specimen - lithium system will be contained by a Cb-lZr vessel which will be surrounded by a 310 steel container. The heating units will be mounted on the outside of this 310 S.S. container. A bottom fill line is requested in order to insure a lithium system free from gas pockets. A slow lithium fill will be made up through the specimen to a level indicated by a probe in the expansion tank.

Cross sections for neutron-evaporation reactions from compound nuclei produced by bombardment of gold with carbon ions and of platinum with nitrogen ions have been determined. The magnitudes of the cross sections are considerably lower than would be predicted on the assumption that neutron emission is the only important mode of decay of the intermediate nuclei. This observation is explained on the basis of fission competition with neutron emission. To a much lesser extent, charged-particle evaporation is also a competing mode of decay. The arguments presented indicate that fission occurs either with comparable magnitudes in several nuclei in the neutron-evaporation chain, or preferentially in one or two nuclei near the end of the chain, rather than predominantly in the initial compound nucleus. Problems arising from the possible existence of isomers in the odd-odd astatine nuclides are discussed.

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