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This memorandum discusses the roflanging of the corroded rear Van Stone flanges at the B Pile after cutting 3/8-inch off the rear gun barrel which should place the B Pile in a condition as good as, or better than that of the D or F Piles.

The face to face expansion of the graphite packing of the pile reduces the gun barrel sum-clearance and if continued will strain the aluminum tubes with ultimate rupture of the Van Stone joints. The graphite expansion may be determined while an aluminum process tube is out of the unit. The distance from the graphite at the inner end of one gun barrel to the corresponding point at the opposite face is measured and compared to a similar measurement that was made during construction of the pile. The replacement of the two scored aluminum tubes at F Pile provided an opportunity to make these measurements. A corresponding measurements made during construction indicates an expansion of 28/32in. at Tube 2174-F and 23/32in. at 2284-F on November 5, 1946, after a total pile exposure of 132,896 MWD. Measurements of gun barrel sum-clearance and aluminum tube length before replacement indicated a graphite expansion of 25/32in. at Tube 2174-F and 24/32in. at 2284-F, which is in reasonable agreement with the above graphite measurements.

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All errors due to diffraction effects in a neutron attenuation experiment are computed. Also a special experiment to measure the forward intensity of diffracted neutrons from lead and copper is described, and the results given. These agree with the theoretical values.

This report summarizes physics experiments carried out in different parts of the 100 area at Hanford during December, 1946. This included work on the D pile, F pile, and experiments aimed at studying the irradiation properties of graphite and metal samples exposed to different radiation environments. Pile tests included reactivity tests, calibrations of control rods, and power coefficient tests.

Four routine shutdowns were experienced during the month. A measurable amount of the excess reactivity held in the control rods at the first of the month has been lost in the decrease in the average accumulated exposure of all the metal in the pile. The vertical safety rod guides have been measured for vertical alignment by the Maintenance Dept. A definite pattern has been found in the misalignment of the guides. The horizontal rod thimbles were borrowed on January 2, 1947 to see if any leaks were present. No leaks were observed but No. 2 Rod and No. 8 Rod had heavy gouge marks along the longitudinal axes. Several thimbles contained white corrosion. During the month two new bismuth tubes were established, 2871-D and 2877-D. This now gives the desired pattern of ten bismuth tubes.

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The two-electrode vacuum tube, or diode, consists of an electron-emitting cathode surrounded by a positive anode (plate). A plot of plate current (i{sub b}) vs plate voltage (e{sub b}) is shown. At low anode voltages, the anode current is limited by the repelling effect that the negative electrons already in the space have on the electrons just being emitted (space-charge effect). When a full space charge is present, the plate current depends upon the plate voltage according to Childs law: i{sub b} {approx} e{sub b}{sup 3/2}. Increasing the plate voltage eventually results in an electron flow equal to total cathode emission, after which further increases in anode voltage will produce practically no additional current (voltage saturation). However, for high field stresses, additional electrons are pulled out of the cathode (field emission), increasing the current even further.

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In order to further understand the nature of changes which occur in the fingers of persons occupationally exposed to radiation a series of experiments were performed on human subjects generally using x-rays at 130 KV potential, 20 ma and at a distance of 10 cm. Doses ranged from 200-600 r. Fourteen subjects were patients being treated by x-rays or radium for other purposes. The other subject was a staff member who occasionally prepared radium plaques containing 130 mgm of radium. Counts were made of the number of vessels in the terminal row of a measured area of the nail fold. In no case was there any detectable change in the nail fold area within 15 minutes of treatment. Observations were continued for up to 56 days and changes observed included hyperemia, pigmentation, erythemia, and some transitory changes in vascular structure of the affected area. A recommendation for continued studies is made.

A group of radiologists were studied for evidences of radiation damage to the skin of their hands. The technics used were the same as those used for routine hand studies of Argonne National Laboratory personnel and consist of examination of wax impressions of the finger ridges and examination of photographs of the vessels and Papillae in the nail fold. Of the 323 radiologists examined by the first method 48% were found to have ridge abnormalities. The incidence of abnormality increased with years of exposure to radiation up to 100% after 35 years. The irregular use of lead gloves does not give adequate protection against damage of the ridges by radiations. Photographs of the nail fold of 152 radiologists were studied and compared to similar photographs of 101 laboratory workers and of 41 persons over 63 years of age. Some of the abnormalities occurred in all 3 groups. All of the changes which were found among the radiologists were found also in the aged. The incidence of abnormality among the radiologists increased with years of exposure to radiation and exceeded the incidence of abnormality in the aged. No radiologist had normal findings after 30 years of exposure. It is concluded that …

A 1,000 Mev synchrotron is under construction. The magnet will be a ring magnet containing about 900 tons of steel. The plates are of 1.2 inch steel with a 0.1 percent carbon content. A diagram of the cross section of this magnet is given in Figure 1. The design of the vacuum chmnber presents some difficulties since the space behind the gap is not large enough to permit easy access to the windings and to the vacuum space behind the gap. The field strength at the gap is 15,000 gauss with a 1 sec. rise time. A d.c. generator of 1,000 v and 10,000 amps and a flywheel will be used to energize the magnet and store the energy. Plans for the vacuum system are not complete, but probably a porcelain system will be used. This will reduce the gap quite considerably. It is planned to inject at 3,000 volts. The energy added to be about 200 ev per revolution. The frequency range is 250 kc/sec to 10 mc/sec; the power required is 10 Kw. A diagrammatic view of the electrical arrangement of the r.f. system is given.The variable inductance is a coil tipped at variable pitch into a pool …

It was desired to determine the distribution of boron in the various steps of the processing of domestic ore concentrates containing high percentages of boron. The experiments described in this report were directed toward that end. Summary of this report are: (1) a black oxide containing 0.6 ppm of boron was prepared from material containing 350 ppm; (2) less than 0.02% of the boron in the original material appeared in the black oxide; (3) the iron step did not remove appreciable amounts of boron; (4) the bulk of the extracted boron was removed in the soda salt precipitation; and (5) some of the boron was removed in the acid leach and calcination steps.

It was desired to establish the adaptability of iron box sludge, a residue recovered in the initial concentration of domestic ores, as a raw material from the production of high purity U{sub 3}O{sub 8}. This report summarizes the experimental work on the extraction of uranium from iron box sludge and that on the removal of V{sub 2}O{sub 5} and P{sub 2}O{sub 5} from the solutions.

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The object of this project is to reduce the impurities and raise the density of rejected slugs and briquetted turnings from these slugs by recasting the material. Summary and conclusions are (1) slugs and briquettes made from turnings produced when these slugs were machined can be recast with great improvement in quality; (2) casting this material is quite hard on graphite crucibles, but a long-range program might point the way to better graphite usage; (3) this metal run alone gives fair yields (88.8% to 94.8%) if heated to 2500 F and then cooled to 2400 F before pouring. Mixing with virgin metal improves the final quality, but does not materially increase the yield; (4) briquettes should not be mixed with magnesium before recasting.

Recent discussions in the group have given rise to the problem of determining whether the beta contamination found in the Columbia River is carried by the algae which are found in the retention basin. The algae accumulate in the basin and apparently remain there longer than the retained water, and thus may be contaminated to a greater extent than the water itself.

This report provides the monthly radiation monitoring sampling surveys for 1947.

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