This paper addresses the reported problem of insufficient air flow through the Fiberglas filters for the air inlets in P-10 production hoods. Since it appears that the replacement of the contemplated filters with either louvers or grilles will not impose any forseen difficulties and will definitely assist in the ventilation design, this substitution has been accepted. Air flow through the grilles or louvers is to be designed to attain a minimum lineal velocity of 200 fpm through the openings.

This report consists of an outline for a program for testing the air-supplied face masks currently being used as protection against P-10 atmospheres at HAPO. The test procedures which follow are intended to determine circumstances under which the mask ceases to offer protection to the wearer. To keep the scope of the test program to a minimum and also to facilitate interpretation of the findings in the light of P-10 atmospheres, the test conditions chosen were those which would be most unfavorable for the mask from a protection standpoint.

In November, 1949, an industrial hygiene study was made of the operations conducted in the Bio-Assay Laboratory, 706 Building, 700 Area. This study was conducted by W.E. Gill and reported in HW-15654. One of the potential health hazards investigated was the use of benzol in laboratory procedures. An evaluation of this problem where the solvent was employed for cleaning glassware indicated that the solvent vapor was present in the workers` breathing zone in concentrations occasionally as high as 170 ppM. Five samples collected at this washing operation showed an average concentration of over 100 ppM; all samples being over the maximum allowable concentration (MAC) of 35 ppM. As a result of the findings of this study several recommendations were made, one of which was the advisability of instituting a program for urine sulfate determinations for the laboratory personnel exposed to benzol. It was felt that this test would demonstrate more precisely than air sampling the actual inhalation and absorption of solvent vapors experienced by the operators and exemplifying such factors as variations in individual respiratory rates and care in the use of solvent during washing.

This HAPO report discusses the toxic effects of methyl isobutyl ketone, known commercially as hexone. Explosive limits are discussed, in addition to animal experimentation results.

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Two new positron active isotopes, B{sup 8} and Na{sup 20}, have been found to decay to excited states of Be{sup 8} and Ne{sup 20}, which in turn decay 'instantaneously' by alpha emission. Their half-lives are 0.65 {+-} 0.1 sec. and 1/4 sec. respectively. N{sup 12} is also found to have a low energy positron group which leads to an {alpha}-unstable excited state in C{sup 12}. The masses of B{sup 8} and Na{sup 20} are 8.027 and 20.015 respectively. B{sup 8} decays by a 13.7 {+-} 0.3 Mev positron, through the same excited state of Be{sup 8} as does Li{sup 8}. Estimates of the energies of the excited state in C{sup 12} and Ne{sup 20} are made.

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Six subjects received a few millicuries Of tritium by inhalation of isotopically labeled hydrogen gas. The concentration of H{sup 3} in the urine of these individuals has been followed for a period of some 15 days. The rate of excretion of the tritium was found to be constant for a given subject but to vary considerably, among individuals. Data on five individuals arbitrarily normalized to coincide at zero time showed a range in biological half-life from about 9 days to nearly 13 days. These values are to be compared with the value calculated for the Chalk River ``Standard Man`` of 13.5 days, assuming the tritim to be confined to the body water.

This general report on radium summarizes the research work conducted by seven AEC contractors since 1943. The costs to concentrate and purify radium from refinery ore residues are discussed. Desriptions and flow sheets of several commercial processes are included to provide background information.

A comparison of the rates of fixation of Carbon 14 dioxide in algae for the processes of photosynthesis, photoreduction and the hydrogen-oxygen-carbon dioxide dark reaction has been made. For the same series of experiments, rates of incorporation of tracer carbon into the separate soluble components using the radiogram method have been determined. The mechanism of carbon dioxide uptake has been shown to occur via two distinct paths. In all cases studied, essentially the same compounds appear radioactive. The distribution with time, however, differs markedly.

This paper presents the requirements of a nuclear amplifier of short resolving time, designed to accept pulses of widely varying amplitudes. Data are given which show that a proportional ionization chamber loaded with a 1,000-ohm resistor develops pulses of 0.5 microsecond duration and several volts amplitude. Results indicate that seven basic requirements are imposed on the amplifier when counting soft beta and gamma radiation in the presence of alpha particles, without absorbers. It should, (1) have a fast recovery time, (2) have a relatively good low frequency response, (3) accept pulses of widely varying heights without developing spurious pulsed, (4) have a limiting output stage, (5) preserve the inherently short rise time of the chamber, (6) minimize pulse integration, and (7) have sufficient gain to detect the weak pulses well below the chamber voltage at which continuous discharge takes place. The results obtained with an amplifier which meets these requirements is described. A formula is derived which indicates that redesign of the proportional ionization chamber might eliminate the need for an amplifier. This may be possible if the radioactive particles are collimated parallel to the collecting electrode.

The relative stopping powers for 300 Mev protons of H, Li, Be, C, Al, Fe, Cu, Ag, Sn, W, Pb, and U have been measured. The results are shown in Table I. The energy spent per ion-pair production in the gases H{sub 2}, He, N{sub 2}, O{sub 2}, and A at 340 Mev proton energy has also been measured. The results are shown in Table II.

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A solution of Pu was prepared for use in a re-investigation of the present 49 titration method. Three 500 microliter portions of the sample were dried and ignited to PuO{sub 2}. From the weight of the residue and the impurity analysis, the concentration, in g/l, of the solution was found to be 222.2, 221.5, and 222.5; average of 222.0. The six samples submitted to the control laboratory in Bldg. 231 were reported as: 219.3, 223.6, 221.5, 220.9, 222.3, and 228.2 (re-run 229.3); average of 222.6 g/l. The 234-5 Laboratory reported: 228.2, 233.3, 220.2, 236.1, 225.2 (re-run 220.6), and 227.9; average of 227.3 g/l. Since the standardization was carried out on April 13, the 231 Lab received its samples on May 11, and the 234-5 Lab received their samples on May 23, a correction for increase in concentration due to decomposition of the water by alpha particles and evaporation was calculated. It was determined that the results reported by the 231 Lab were very consistent (except for one determination) and that the average value agreed with the gravimetric determination. The average results from the 234-5 Lab are 2% higher than the gravimetric results. Further studies are being made on the chemical …

Malonate has been found to inhibit the formation of malic acid during short periods of photosynthesis with radioactive carbon dioxide. This result, together with studies which show the photosynthetic cycle to be operating normally at the same time, indicates that malic acid is not an intermediate in photosynthesis but is probably closely related to some intermediate of the cycle. Absence of labeled succinic and fumaric acids in these experiments, in addition to the failure of malonate to inhibit photosynthesis, precludes the participation of these acids as intermediates in photosynthesis.

The fission reaction has been observed with high energy accelerator projectiles for elements as light as tantalum but has not been reported for medium weight elements. The present note presents evidence for the occurrence of reactions which are probably most properly described by the term 'fission' and which seem to occur with very small yield throughout the region where this type of reaction is only slightly exoergic or even endoergic with respect to mass balance. In the course of detailed investigation of the spallation of copper and the variation of the product yields with energy of the bombarding particle the threshold for formation of radioactive Cl{sup 38} (38-minute half-life) from elemental studied. The energetically most economical way in which Cl{sup 38} might be spallation reactions is by emission from the bombarded copper nucleus of nucleons in groups such as alpha-particles instead of single nucleons 0 The energetic requirements for the reaction Cu{sup 63}(p,pn6a)Cl{sup 38}, in which the maximum number of alpha-particles are emitted, include (1) the mass difference between the reactants and the products and (2) the excitation energy which the alpha-particles must have in order to pass over the coulombic barrier, Since the reaction is endoergic with respect to …

It is desired at this time to present in summary form a factual history of the Building 234-5 operations, encompassing not only the immediate pre-start-up period from April to July, 1949, but including the major obstacles encountered in the succeeding interval to the end of 1949. This report is intended to serve not only as a review of 234-5 operations during this period but also as a documentary evidence of the difficulties experienced and the manner in which they impeded the start-up. This report presupposes a certain familiarity with the background of the 234-5 Building. To one unacquainted with the scope of this project, or for those desiring a background review, reference should be made to Document HM-253, ``234-5 Building Program Review``, by D.D. Streid, dated April 22, 1949. It must be realized that any attempt to discuss in detail all the circumstances and difficulties contributing to the start-up period would be disconcerting to the reader, and would very likely be repetitive. Therefore, although it is far from the writer`s intent that a cursory review will suffice, the presentation will be as nearly as practicable, chronological and comparative. For the sake of clarity it will be necessary to present several …

Since the end of the war when the long-lived isotope of carbon, C{sup 14} became available a new tool has been applied in the study of photosynthesis. Because of the interest evoked by the tracer method, research in all areas of photosynthesis has expanded. There have been reviews on various aspects of photosynthesis such as the primary photochemical reaction, quantum efficiency products, and comparative biochemistry, many discussions of which were included in the monograph of The American Society of Plant Physiologists, ''Photosynthesis in Plants''.

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The maximum nuclear accident which could occur in a Na-cooled, Be moderated, Pu and power producing reactor is estimated theoretically. (T.R.H.) 2O82 Results of nuclear calculations for a variety of compositions of fast, heterogeneous, sodium-cooled, U-235-fueled, plutonium- and power-producing reactors are reported. Core compositions typical of plate-, pin-, or wire-type fuel elements and with uranium as metal, alloy, and oxide were considered. These compositions included atom ratios in the following range: U-23B to U-235 from 2 to 8; sodium to U-235 from 1.5 to 12; iron to U-235 from 5 to 18; and vanadium to U-235 from 11 to 33. Calculations were performed to determine the effect of lead and iron reflectors between the core and blanket. Both natural and depleted uranium were evaluated as the blanket fertile material. Reactors were compared on a basis of conversion ratio, specific power, and the product of both. The calculated results are in general agreement with the experimental results from fast reactor assemblies. An analysis of the effect of new cross-section values as they became available is included. (auth)

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