A capillary-drop method of producing spherical shapes of brittle materials less than 0.l00 inch in diameter was developed. It appears to be a feasible means for producing large numbers of pebble-tyne fuel element cores. Coating of pebble-type fuel element cores by the coating-pan technique, though not adequately developed, showed promise. (auth)

ON NUCLEAR PHYSICS LABORATORY AT CANEL. The critical experiment facility at CANEL is described. Information of the mature of experimental assemblies and operations is included. Safety features of the building, equipment, and operations are pointed out. Possible accidents and the resulting hazards to surrounding areas are analyzed. The make-up of the surrounding area is described. (M.C.G.)

Optical microscopic examination of air- and rain-borne dust shows most of the particles to be less than one micron in diameter. Electron microscopic examination of the same dust shows predominantly clusters of particles whose individual diameters are in the range 200 to 1000 A. The residue obtained by filtering rain water through a millipore filter is found to be slightly radioactive in more than half the cases observed.

During an experiment involving alpha phase annealing (at 610 to 655 deg C for 5 and 10 min) of beta-quenched uranium, it was determined that the relatively coarse, irregular shaped grains (0.08 to 0.150 mm in diameter) in the beta-quenched structure, were replaced by fine equiaxed grains (0.04 to 0.09 mm in diameter). (auth)

In the most general sense, an accelerator is any device designed to give kinetic energy to ions or electrons. According to this definition the earliest cathode ray and canal ray tubes, made before the turn of the century were accelerators, the same principle is used in the x-ray tube, the cathode ray oscilloscope, the mass spectrograph, the electron microscope, and many other modern devices. However, we shall limit this discussion to those accelerators made for the particular purpose of inducing nuclear reactions, and to a few others that may be of interest in this connection, although they were originally designed for other purposes, such as high-voltage x-ray tubes intended for deep therapy or the radiography of metals. Although much work related to accelerators is thus omitted, it must not be forgotten that the principles learned and the practical experience gained by this work were of great importance in the development of the machiens now used in nuclear physics.

An instrument was developed to measure nondestructively the lithium content of target slugs for the SRP reactors. The slugs consist of cylindrical pieces of Li-Al alloy, approximately 0.8 inches in diameter and 12 inches in length, clad with aluminum. The instrument utilizes neutron transmission to determine the Li content in the range 3% to 7% Li.

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Tests have been made to study the effects of lowering process water pH from pH 7.7 to the range pH 6.2--7.3; of reducing the amount of sodium dichromate inhibitor added to the water; and of eliminating the filtration step in the water treatment process. The results on the pH testing showed that reducing the pH of the cooling water would reduce aluminum corrosion rates. The plant specification has been changed to lower process water pH from 7.7 to 7.3 and plant scale testing of pH 7.0 water is in progress. Reducing the dichromate concentration in the water from 2 to 0.2 ppm had no deleterious effects on the aluminium pile components but might cause pitting of the carbon steel pile effluent lines. The use of unfiltered water is technically feasible from the stand-points of corrosion and film formation but probably would cause a sizable increase in the radioactivity of the pile effluent water. 6 figs., 5 tabs.

A desirable radio-iodine emission goal for all HAPO has recently been set at one curie per day maximum. At the same time it was suggested that a more relaxed limit of ten curries per week with no more than three in any one day, would probably be satisfactory. To assure the achievement of these goal figures in the separations plants it was deemed necessary to either cool'' the irradiated material a greater length of time than is presently done before processing, or provide more efficient, iodine retention facilities. Increased power levels, higher production rates, and an increase in the awareness of radio-iodine emissions, have all coupled together to make present facilities generally inadequate when processing material aged less than about 100 days. Several alternate methods of providing additional iodine retention facilities for Redox were preliminarily scoped and presented for consideration. The purpose of this report is to present a scope design for improving iodine emission control at Redox.

This is the thirty-sixth progress report of the Laboratory for Nuclear Science at the Massachusetts Institute of Technology. Progress during the period of November 30, 1954 through February 28, 1955 is reported.

This report summarizes work completed during the Redox Plant shutdown in January 1955. An analysis of major difficulties encountered, improvements made during the shutdown, and building design deficiencies brought to light by the shutdown are discussed. (JL)

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In the light of Redox Plant performance since the start-up on 2-3-55, coupled with a review of the technological factors involved in the current flowsheet, a departure from the process program outlined in HW-34882 is herewith presented as an addendum to that document which will also serve to detail the corresponding items in the latest Redox Test Program, HW-35069. The purposes of this document are to: (1) Discuss the need for modifications of the program given in HW-34882, and (2) Present the details of the proposed revisions.

In view of contamination difficulties within the Redox operation, number of items are being considered to improve this situation. It is the objective of this document to list and describe seven times which it is felt would contribute most toward improvement. It is also an objective to present for RDS-D-12 Group consideration the recommendations of representatives from Manufacturing, Technical, and Design in these matters with the expectation that a project proposal written in general terms for overall contamination improvement would be prepared.

The new KW reactor was placed in operation on January 4, 1955, and had been running at relatively low power levels for only 17 hours when it was shut down because of a process tube water leak which appeared to be associated with a slug rupture. After several days of unrewarding effort to remove the slugs and tube by customary methods, it developed that considerable melting of the tube and slugs had taken place. It was then evident that removal of the stuck mass and repairs to the damaged tube channel would require unusual measures that were certain to extend the reactor outage for several weeks. This report documents the work and findings of the Committee which investigated the KW reactor incident. Its content represents unanimous agreement among the three Committee members.

A knowledge of the mechanical and physical properties of uranium is important in understanding its pile behavior. The effects of irradiation on the properties of uranium will be dealt with in another chapter. However, it is important to know and understand the pre-irradiation properties of uranium prior to investigating the effects of irradiation. This chapter discusses the mechanical and physical properties of uranium.

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.

Production rates of the Hanford reactors can be increased in proportion to the quantity of process cooling water which can be supplied to them. This water must be of such a quality that slug and tube corrosion rates are acceptable, the gross activity of the effluent water must not be excessive, the concentration of specific radioactive isotopes constituting a radiological hazard must be minimized, and the film formation rates should be as low as possible. In the Hanford water treatment process, the filter plants are the controlling factor in determining the quality of the water, and one of the elements limiting the quality of water. A major development effort was therefore undertaken to develop methods of increasing the capacity of the existing filter plants. This report presents the result of this development work from its inception in 1951 to its conclusion in 1954.

The purpose of this course is two-fold. It should serve as a review for the metallurgist of the classical metallurgical concepts applied to such metals as uranium, thorium, plutonium, and zirconium. These metals are relatively unfamiliar to the metallurgist, but the concepts are still the same ones applied to familiar metals. The second purpose is to acquaint the non-metallurgist with the reasons for selection, advantages, and disadvantages of the various fuels and structural materials used in a reactor. Thus, there are two purposes: the first is conceptual, and the second is explanatory. A blending of the two must inevitably result in an over-simplification of the metallurgical concepts and an assumption of certain background material which, actually, may not be available to the non-metallurgist. The present lecture is an introduction to the material to be covered. This lecture will have two purposes. The material to be presented in the remaining lectures will be outlined briefly, and the various concepts to be covered in this course will be discussed.

This report discusses two methods which have been considered to reduce the rear face activity. The first involves the use of a solids purge to scour out the activity, and the second employs the use of a chromic acid purge to put the activity into solution. Solids purging is found to be ineffective in reducing rear face activity levels. A chromic acid purge conducted at 60 C for 1/2 hour can be expected to reduce the Zn{sup 65} activity level about five fold without injuring the reactor or causing any harmful aftereffects.

This document provides tables which give the computed acid, silicate, and silica requirements which will be necessary after completion of the water treatment plant expansion programs.

This report discusses a system which has been conceived whereby additional flexible reactivity control in the production reactors can be achieved by introducing neutron absorbers contained in thin flexible metal strips between the slugs and the process tube wall. These splines are potentially attractive in that it is possible they could be used to provide additional flexible control during operation as well as temporary control during outages.

It is the purpose of this document to review and up-date the previously presented scope basis for the activated silica installations in light of the existence of the Phase I portion and the present expected water flow requirements of Project CG-558. It is the further purpose to outline the recommended scope bases for the sulfuric acid addition system for pH correction at all areas.