Description of Purex plant process for irradiated uranium for the separation and decontamination of plutonium and uranium from each other and from fission products.

From objective: "The objective of this work was to design, develop, assemble, and test and automatic analyzing monitor for recording the prominent isotopes in reactor effluent cooling water."

The spatial distribution of thermal neutrons in a reactor lattices cell is of fundamental importance for many reasons. First of all, this information allows the determination of the relative absorption rates in each component of the cell which in turn enables a determination of the thermal utilization, and the diffusion length of the lattice. In addition, the observed spatial distributions of thermal neutrons in the lattice cell is of major interest in testing various approximations to the solution of the transport equation such as the P1 and P3 solutions.

During the period when the writer mixing fuel element was being evaluated, a small Litton glass lathe and a General Electric Fillerarc welder were used to weld the mixing spool to the fuel element. Due to the condition of these units and to the numerous difficulties encountered with them, it was deemed necessary to design and procure a semi automatic welding unit which could weld in excess of three hundred fuel elements per day.

Hastelloy F is a prime contender as a material of construction for plant dissolvers in the power fuel reprocessing program. Consequently, the fabrication and installation of dissolver was undertaken to delineate any unknown problems associated with the use of Hastelloy F; and, at the same time, to provide a vessel for development studies on the Niflex or the Sulfex processes. The purpose of this report is to describe the actual basis for design as well as to present the problems encountered during the fabrication of the vessels.

In HAPO solvent extraction processes there are two independent aspects of nitrous acid chemistry. One concern the decomposition of the solvent through nitration reactions and the attendant problems. These reactions are autocatalytic in the presence of nitric acid and have threshold values for both temperature and nitric acid concentration for a given solvent below which nitrous acid disappears and above which it is generated with continuous destruction of the solvent. These reactions are identical to those found in the prior study of the hexone system.

A number of the questions which have been posed to us in the subject references are commented upon below. These have been reviewed by personanel of the Research and Engineering Operation and the Facilities Engineering Operation, Chemical Processing Department, and of the Chemical Research and Development Operation, Hanford Laboratories Operation. Particular acknowledment is given G. J Alkire, J. P. Duckworth, J. B. Fecht, R. G. Geier, E. R. Irish, H. M. Jones, G. C. Oberg, A. M. Platt, W. H. Reas, W. C. Schmidt, R. J. Sloat, W. H. Swift, M. T. Walling and L. L. Zahn of these organizations for assistance given assembling this information.

In early July, 1958, it appeared that Columbia River temperature at HAPO would be near 24.5ºC by the end of August. River temperature were averaging 4º to 5º above 1957 figures and were 3º to 4º above the ten year highs. It seemed desirable to examine the problem to determine if any corrective measure could be taken, since it was apparent that production losses were imminent.

The HAPO Critical Incident Alarm, Model I, is an instrument designed to give an audible and visual alarm signal in the event of a critical incident to which it is exposed. There will be thirty-one (31) of these instruments installed and several spares located in the various manufacturing buildings in the Chemical Processing Department where there exists any possibility of a critical incident occurring. The instrument is intended as a post or after-the-fact warning device. It will offer no protection prior or leading up to, nor prevent, a critical incident. They are intended to be operated from the 115 V. A.C., 60 C.P.S. emergency line power. The instrument is self-contained, including the radiation detector, and will be calibrated to alarm at 500 mr/hour in a gamma field.

Nearly all nuclear reactors being designed and built today- whether for research, power, or productions of fissionable materials- use recirculating fluids for cooling. However, a number of production reactors are still operating with single-pass cooling by treated natural water. The Hanford Atomic Products Operation of the General Electric Company presently operates production reactors for the AEC at Richland, Washington. The first reactors were built during World War II, and utilized a standard water treatment which was designed to provide large quantities of settled, filtered Columbia River water for once-through cooling.

Because of the excessive vertical fragility and high replacement costs of mice-window G-M tubes used in vertical and horizontal lead-pig shelf counters, it was requested that a simple system of conversions to reliable scintillation detection be accomplished.

The final percentage of xenon created by fission in uranium and plutonium is a function of the neutron flux intensity. The flux dependence results because axenon 133 and 135 can be converted to a a stable xenon isotope by neutron capture instead of decaying into cesium.

The Interim Power Fuels Reprocessing Program, as established by the Atomic Energy Commission, provides the service of recovering uranium, thorium, plutonium, etc., from irradiated fuels discharged from non-production reactors of both public and private ownership. To provide this service on an interim basis and at minimum capital investment, the Commission has assigned the processing responsibility for the various fuel types to several AEC sites. The sites are to be assigned fuel types most similar to their normal production. As a result, HAPO has been assigned the responsibility for processing the low enrichment uranium and uranium oxide type fuels with isotopic content up to 5% uranium-235. In addition, some plutonium base fuels will be processed at Hanford.

In considering the problems associated with the measurement of SSNM content of Non-Production Fuels, two distinct problems are apparent. The first is the technical problem of obtaining highly accurate measurements in a complicated chemical and physical system. The second is the administrative problem of choosing a measurement system which provides a basic of financial settlement acceptable to both the seller (reactor operator) and the buyer (Commission).

The major portion of transfers and inventory in the Chemical Processing Department are dependent on volume measurement. Good volume measurements are therefore essential to good SS material control. Considerable attention has been given to the volume problem especially on primary transfer points. Document HW-57888 discusses the biasing effect pf temperature on manometer oil. HW- 57866 given the procedure for vessel calibration. Other undocumented correspondence has discussed recent calibrations and certain aspects of temperature considerations in the volume determinations. However, there is a need to document for future reference the consideration given temperature and provide at the same time information which covers the temperature angle on all volume methods used in the Chemical Processing Department.