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Six determinations have been made of the half life of polonium with four different steady-state, resistance-bridge calorimeters and five different samples of polonium. These six values of the half life have been weighted and combined to give a grand-mean value of the half life of 138.4005 + - 0.0051 days.

This document from Savannah River Plant reports progress in January 1953. Heavy water studies include corrosion inhibitors and sulfide deposition. Reactor materials studies include uranium fuel elements and aluminium sheaths and special materials to include thorium and bismuth. Reactor technology studies include control systems, tritium production, CMX, moderator purification, concrete shield heating. Separations technology studies include Purex process, 221 building equipment, and fuel element handling.

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This report covers the examination of nine process tubes, five tubes from B Pile and four from H Pile. Four of the tubes from B File were removed because they were leaking and the fifth was removed because it contained a stuck ruptured slug. Tube 2681-H was removed for graphite mining, tube 2852-H was removed under PT 313-105-14M ``In-Pile Evaluation of 63-S Aluminum Process Tubes,`` and two tubes were removed from channel 0961-H under PT 105-506-E, ``Recirculation of Pile Cooling Water.`` Visual inspection was made of the inside and outside surfaces of the tubes before and after cleaning with cold 10 per cent nitric acid. Samples varying from one to four inches in length were taken from each section and transferred to the 108-B Metallurgical Laboratory for close examination to determine depth of pitting, 72-S cladding thickness, and wall thickness. These determinations were made at specific points in each section on what appeared to be the area of severest attack. It is indicated on six of the tubes where the sample was taken on the circumference of the tube.

A list of studies approved at the meeting is given with programs outlined in the appendix. The following topics were discussed: (1) safety; (2) security violations; (3) arrangements made for interviewees with physics training to visit Building 777; (4) procedures written for handling various fissionable materials on a large scale in the fabrication laboratory; (5) backlog of orders at the Laboratory shop; (6) that the limited number of applications do not justify the use of depleted uranium in the Laboratory; (7) that Savannah River Plant can follow Hanford requirements as to the average and variation of U-235 content in sidestream materials; (8) that Laboratory is to supply the various dimensions and tolerances that probably will be required for tubes with spiral ribs; (9) shipping of various dies and aluminium shapes now being held by aluminium fabricators; (10) obtaining proper hydraulic performance of fuel assemblies; (11) preliminary scopes of work covering process requirements for producing natural uranium elements in plate and tubular form; and (12) arrangements to be made to review the Nuclear Metals Program.

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S>Of primary interest in a military reactor is the desirability of quick and easy maintenance of as much of the system as possibie throughout the lifetime of the power plant. It is therefore desirable that no serious amounts of long- lived activity build up in equipment outside the core. An investigation was made to determine the activity due to small amounts of cobalt and tantalum in the stainless steel core of the APPR-1. The investigation indicates that equal weight percentages of Ta and Co would build up about equal activities in the core after 1.5 years of operation. The use of 347 stainless steel containing a nominal 0.2 wt.% Co would therefore produce a more serious activation problem than is now being experienced wlth the present 304L core. A desire to reduce the production of long-lived activities would then require specifying a low tantalum as well as a low cobalt content if 347 stainless steel were used for the second APPR-1 core. Fabrication of a low cobalt 304L core is therefore an attempt to reduce and to simplify the activation problemn (A.C.)

A 1585 hr run was completed on the 400A-1 pump with a 0.4 m UC/sub 2/SO/ sub 4/ fuel solution as the pumped fluid, during which it was attempted to operate with gas bubbles in the solution. The gas content ranged from 0.56 ml/gm of solution to 1.189 mi/gm of solution and the gas other than CO/sub 2/, which was assumed to he nitrogen, varied from 0.39 ml/gm of solution to 0.966 ml/gm of solution. Because of uncertainties in the CO/sub 2/ solubility it cannot be stated conclusively that the liquid was or was not saturated. However, the loss of metal at a number of places due to corrosion and/or gas bubble erosion makes it advisable not to operate a pump of this exact design at or near gas saturation. The 1585 hr above are the last of 13185 hrs maintenance free operation. A general examination of the pump dlsclosed severe corrosion and softening of the Stellite 12 overlay on the 347 stainless steel thrust bearing shoes. The thermal barrier seal weld had cracked and there was noticeable corrosion in the region betwoeen the thermaI barrier gasket and metallic O'' ring seal. (auth)

The reaction between uranium dioxide and aluminum has been studied at 600 deg C and below. At 600 deg C the visible reaction occurred within a few hours, while, for example, at 500 deg C and below, the specimens had to be at temperature for several days in order to show signs of any reaction. The method of manufacture of uranium dioxide had a pronounced effect on its compatibility. Granulated and high-fired oxides showed lowest, and the steam-treated oxide showed maximum, reactivity. The fact that finer oxide powder partlcles react faster than coarse ones was according to expectations. Mallinckrodt U/sub 3/O/ sub 8/ powder of very fine particle size reacted severely with aluminum during a 1 1/2-hr test at 610 deg C. (auth)

A stress analysis is presented of a spherical shell subjected to a line load acting along a latitude circle in a direction normal to the plane of that circle. (auth)

It was demonstrated that neptunium(IV) can be readily absorbed onto anion exchange resins from 6 M HNOsub 3/ containing ferrous sulfamate and hydrazine or semicarbazide, separated from plutonium, uranium, and common metallic impurities by washing the resin at 25 deg C with 6 M HNO/sub 3/ containing ferrous sulfamate and hydrazine or semicarbazide, separated from fission products and thorium by washing the resin at 60 deg C with S M HNO/sub 3/- 0.01 M HF containing hydrazine or semicarbazide, and eluted at concentrations greater than 40 g Np/l with 0.35 M HNO/sub 3/ at 25 deg C. Decontamination factors of greater than 10,000 from uranium, plutonium, and common metallic contammants, greater than 25,000 for fission products normally expected in the feed (mainly Zr-Nb with some Ru-Rh), and greater than 1000 for thoriuin are obtainable under proper operating conditions. Because of the low processing rates, the necessity for carrying out the absorption cycle at 25 deg C and the absence of radiation daraage problems, Dowex 1, X-4 (50-100 mesh) or Dowex 21K (50-100 mesh) resins are considered the best choices for this application. Gassing occurs with the use of ferrous sulfamate - semicarbazide reductant but is not a serious problem and …

The check valve for the Hallam Power Reactor uses a knife-edge bearing for the flapper in place of the usual journal-type bearing. Mechanical cycling in sodium at 600 deg F was used to check operation of this bearing. A total of 309 mechanical cycles was completed with no apparent malfunctioning of the valve. Measured leskage rates were 0.46 gpm at 0.93 psig, 0.73 gpm at 3.4 psig. and 0.32 gpm at 5.9 psig. (M.C.G.)

A prototype of the two-coolant-region pump shaft freezeseals intended for application to the Hallam Power Reactor sodium pumps was fabricated. Tests under simulated reactor service conditions revealed satisfactory operation only when the lower of the two regions received heat from the circulating fluid (tetralin in the tests). With the inlet temperature of tetralin to the upper region of the seal maintained at 95 deg F and that to the lower region held in the range 240 to 285 deg F the sealfunctioned satisfactorily for 1100 hr. When 95 deg F coolant was circulated through both sections of the seal excessive cooling occurred, resulting in either improper formation of the seal or in seizure of the shaft when rotative speed was low. In this case, the cooling load on the seal varied directly with both shaft speed and bulk sodium temperature. A maximum cooling load of 2.56 kw occurred at a shaft speed of 840 rpm and with a bulk sodium temperature of 1000 deg F. (C.J.G.)

This letter is for the purpose of supplying the information that you requested at the meeting of the sub-committee on Project Vela. It is divided into three parts: (1) Radiations from nuclear weapons; (2) Backgrounds for Vela Signal Detectors; (3) Discussion of the NASA program.

Cavitational flow has been known to exist in-rear crossheader ``Parker`` fittings at B, D, and F Reactors for the last five or six years. Calculations showing initiation of cavitational flow as a result of high flow rates in the present fittings were verified by experimental data in 1954. A study is currently being conducted to determine the required plant modifications to obtain flow increases on the order of fifty percent above existing flows. This study and the results of preliminary tests that show nominal flow increases may be obtained by reaming rear crossheader fittings has focused attention on the condition of existing rear face piping. To obtain an estimate of the effect of cavitation in rear crossheader fittings resulting from past and current operating conditions, twenty one fittings were examined during the period October 6, 1959 to November 30, 1959. This document reports the inspection results.

Albino rats were exposed to a In/sub 2/O/sub 3/ dust aerosol of mean concentration 64 mg/m) for 3 months. The retention of In in the tissues and the mobilization of In from the lungs and tracheobronchlal lymph nodes were determined. The results indicate chemical toxicity. (D.L.C.)

A block-loading of striped columns and tubes simulating a blanket loading were analyzed for product (Pu, tritium, E-metal) after irradiation in IP-255-A-9-FP. Results are rationalized to full-pile values; pile conversion ratios and pile gains are given.

Discussion is given on the welding fabrication of tungsten, molybdenum, niobium, and tantalum. Properties which make the four refractory metals important are tabulatcd along with titanium which is given for comparison. Extensive evaluation was conducted using the gas, tungsten arc welding process employing both manual and machine welding. Design data were obtained exclusively from machine welded sheet materials. Flash welding, resistance spot welding and brazing, electron beam welding, and high frequency resistance welding processes were also applied to molybdenum alloys. The oxidation of molybdenum, tantalum, and niobium in flowing air at 2000 deg F is also given. (P.C.H.)

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During this period, continued effort has been placed on the fabrication of high burnup irradiation test specimens, on additional UO2-PuO2 and PuO2 sintering, on oxygen diffusion and thermal expansivity measurements using UO2-PuO2, and on the preparation of reproducible PuO2 powder.