Memorandum from A. W. Waltner to Dr. Clifford K.Beck

%MurNBuranium000053; ]> Memorandum from A. W. Waltner to Dr. Clifford K.Beck Machine readable transcription Waltner, A. W. Creation of machine-readable version: Russell S. Koonts Creation of digital images: Russell S. Koonts Conversion to TEI.2-conformant markup: Russell S. Koonts ca. 9 kilobytes NCSU Libraries Raleigh, NC Modern English, MurNBuranium000053

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15 November, 2000

Nuclear Reactor Digitization Project

Raymond L. Murray Reactor Project Notebook

Illustrations have been included from the print version. Scanned by Russell Koonts with Photoshop 5.0 software. Memorandum from A. W. Waltner to Dr. Clifford K.Beck A. W. Waltner

1 p. Manuscript copy consulted UA 105.16

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Library of Congress Subject Headings 1953 English LCSH manuscript 24-bit color: 400 dpi Memorandum from A. W. Waltner to Dr. Clifford K.Beck Typescript 1 p. 1953 MurNBuranium000053

TO: Dr. Clifford K. Beck FROM: A. W. Waltner CC: Reactor Committee SUBJECT: Preparation of Uranium Foils

"Rossi and Staub" suggest the following procedure in preparing U235 foils for spiral fission:

Preparation of Foils

"Uranyl nitrate is dissolved in a minimum quantity of alcohol. A solution of 1 or 2 per cent of Zapon lacquer in Zapon thinner is prepared and added to the first solution until the concentration of uranyl nitrate is about 50 mg/cu cm. The nitrate concentration may be much lower, but the value mentioned should not be greatly exceeded.

This solution is applied to an aluminum foil in a thin layer by means of a soft brush. The brush should not touch again any portion of the foil from which the solvent has evaporated. The foil is then baked for three for four minutes at about 550°C to burn off the Zapon lacquer and to convert the uranyl nitrate to U3O8. If platinum foil is used, the baking temperature may be 800 or 900°C. The higher temperature will result in more nearly complete elimination of Zapon and quanti- tative conversion of uranyl nitrate into U3O8.

When the foil has cooled, it is rolled flat between sheets of paper and the coated side is rubbed smooth with a soft tissue. Initially, the coated surface will exert considerable frictional drag on the tissue but this rapidly diminishes, without apparent removal of oxide, and a smooth lustrous surface is produced.

A single layer of U3O8 applied by this method is, and apparently must be, quite thin. However, the procedure may be repeated until the desired surface density is reached. The coating is very tenacious and will withstand sharp bending of the foil.

If the foil is to be coated on both sides, as it must be for the preparation of spirals, it is advisable to paint alternately on the two sides rather than to complete to coating on one side before beginning the other

Small areas of foil are conveniently painted, on a flat surface, by hand. Larger areas can be more easily handled if the foil is wrapped around an aluminum drum, which is rotated against the brush.

The aluminum foil that has been used in most of the spirals, is prepared for coating by lightly etching the surfaces in a dilute sodium hydroxide solution. It is carefully cleaned with water and alcohol and thoroughly dried before the painting is begun.

Rossi and Staub--Ionization Chambers and Counters--McGraw-Hill (1949)