The problem of the separation or enrichment of isotopes is as old as the knowledge of the existence of isotopes of stable elements. The article focuses on the mass-dependent property of atoms continuing to be investigated in laboratories to test its usefulness for new solutions to this problem.

With discussion under way concerning power production by chain reacting piles, it becomes pertinent to consider the ration of the temperature of the hottest spot in the pile to the average exit temperature of the cooling stream. This is important because the temperature of the hottest spot in the pile is one of the limiting factors in determining the maximum power at which a pile can be operated. However, the higher the temperature of the emerging cooling stream, the more efficient can be the thermal engine operated by it. Thus the ideal situation is to have the average exit temperature of the cooling stream as near as possible to the hottest temperature of the hottest spot in the pile.

Abstract. Some idealized calculations (CP-807) relating to the design of heat exchangers for minimum holdup of pile liquid are presented in compact form to facilitate quick estimates. Their use is illustrated by application to a falling film type exchanger.

Technical report with short reports from the (1) Experimental Nuclear Physics Group; (2) Theoretical Physics Group ; (3) Lattice Design Group; (4) Pile Design Group; (5) Exponential Experimental Group; (6) Radiation Group; and (7) Shielding Group.

The present report is concerned with the electronic relay which, upon the reaching of a pre-determined value of ionization current in the associated chamber, actuates the safety rod release mechanism. The are here proposed two independent suggestions: (1) An improved trip circuit of such sensitivity and stability as to allow it to be actuated by a signal directly from the chamber without the necessity of interposing intermediate amplifier stages. The value of chamber current at which tripping occurs is stable to +- 0.4%. (2) A triple-wound relay to prevent shut-downs of the pile which would otherwise be caused by development of defects in the safety circuits.

Calculations were made to determine the temperature at various points of a thick disc and cap, on the assumptions that the heat production rate is uniform throughout the slug and that the slug is in perfect thermal contact with the cap. Results obtained by different methods of computation are compared with each other and with results obtained by Drew on the Paschkis electrical network computer at Columbia University.

Technical report with short reports on (1) Effect of radiation on organic compounds; (2) Effect of radiation on separation processes; (3) Effect of radiation on water and aqueous systems; and (4) Effect of neutrons on graphite.

Technical report with short reports on (1) P-9 recovery from UO2F2 solution; (2) Correlation of theories on action of radiation on matter; (3) Literature surveys on organic compounds and on chemistry of UO2F2; (4) effect of radiation on organic compounds; and (5) Effect of radiation on 100 area construction materials.

The thermal decomposition of the higher oxides of praseodymium and americium have been investigated.

This report describes observations of a sample of Carbon-14, or radiocarbon, made using the method of mass spectrometry.

This report discusses the field of nucleonics in the wake of the development of the atomic bomb, ruminating on the training and curriculum necessary for the next generation of chemical and nuclear engineers.

From abstract: "A pile will run steadily at an arbitrary level if it is just critical. For a pile not at equilibrium, equations of motion can be set up that contain as variables the pile power, the number of delayed neutron emitters and, in case it is of importance, also the pile temperature. The coefficients will depend on the average lifetime of the neutrons in the pile, the fractions and periods of delayed neutrons, temperature coefficients of resistivity and similar quantities. For a definite 'excess resistivity', which may be positive or negative, the power level will change exponentially with time with periods determined by the so-called 'labour' relation. For control and safety problems the transient behavior of the pile under reactivity changes has to be investigated. A number of limiting cases can be solved explicitly. A general method for the solution of the pile equations is available for small deviations from a steady state. In this case a pile impedance can be defined in close analogy to electric circuit theory."

Positive and negative mesons produced in a common target in the cyclotron are received in two photographic plates. In the magnetic field of the cyclotron, negatives are deflected to one plate, positives to the other. The mesons must pass through an absorber before entering the plates in order to be observable.

This report details events of importance reported by the Hanford Operations Office for the week ending January 12, 1949.

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Failure of a vertical safety rod thimble at 105-B has led to consideration of a stainless steel (SS) thimble as replacement. 1/16 in. SS would result in 4% loss in control power of that safety rod. If all thimbles were replaced by 1/16 in. SS, there would be a reactivity loss of 790 ih.

It was agreed during a meeting on July 10, 1945, investigation should be made to determine how fast and in what fashion the temperature of the effluent water from the 100 Areas is dissipated in the Columbia River. A preliminary report on these investigation was issued March 1, 1946: it discussed the testing techniques developed and the results of a survey made at the 100-B Area. Following a review of the data and tentative conclusions resented therein, it was agreed to extend the survey using similar technique: to the D and F Areas, and to determine if the tentative conclusions were substantiated.

This report describes a test performed on April 2, 1947 to determine the reactivity power coefficients and the graphite relaxation period of the F Pile in accordance with the procedure described by this Production Test.

This barely legible document contains information on slug testing results and autoclave performance. Reactor physics, corrosion, chemistry and instrument development are also discussed.

On July 14, 1949, and office memorandum was written about operations of a reprocessing building on the Hanford Site being suspended due to the mishandling of some plutonium powder. The letter describes the process of decontamination of the building surfaces, and the ventilation of the rooms of that building. It also describes the problem with the ventilation fans due to increased temperature and pressures.

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Due to a forecasted increase in pile area production as well as a possible decrease in batch size of the separations process, an increase in the capacities of the separations plants is indicated. It is the purpose of this report to review this relationship in the light of existing data and to determine how this additional capacity can best be attained through the use of either the proposed semiparallel or complete parallel methods of operation. Emphasis will necessarily be given to consideration of cost, timing, use of minimum buildings and equipment, and the obtaining of optimum production time cycles.

This trip was to provide an answer to these questions: Are Hanford meteorological instrumentation, methods, and records adequate? Do they conform to generally recognized practice? Are they effectively utilized? What is the percentage frequency of wind classified according to conditions normal, least favorable and most favorable for dilution? What is the habitability of the Wahluke Slope north and northeast of the Columbia River, considering stack gases, various stack heights, any pertinent meteorological features? What is the habitability if the only contaminating sources are the piles? In preparation for and in the event of a major catastrophe with attendant relief and evacuation operations, which additional observation should be taken: What weather data should be assembled from the general vicinity of Hanford: What sampling program should take place immediately after the event. To these may be added a question raised by Dr. Parker in connection with the high level of contamination at the ground in the vicinity of the separations. areas.

The total power output of a unit may be represented by the power output of the most productive tube or tubes multiplied by a quantity designated as the ``number of effective tubes.`` The number of effective tubes observed at 105-D under two different arrangements of poisoned columns has been compared with values of this quantity calculated from theory. It was found that in each case the observed number of effective tubes was about 5% less than the ideal number obtainable by an optimum arrangement of the poison. In the case in which two poisoned columns in the pile took up 110 ih it was found that the loss consisted of 2% due to the necessary presence of a control rod in the pile and 3% due to the fact that the actual arrangement of the poison was not the optimum one. In the case in which a single, off center, poison column took up 60 ih, it was found that very little of the loss was due to the presence of the control rod and almost all of it was due to the eccentric position of the P-column. As a further result of this study, it was found that, apart …