POWER REACTOR PROGRAM. Progress Report to Savannah River Operations Office, AEC for the Period November 1, 1960 through November 30, 1960

Technical Report · Fri Jan 20 04:00:00 EST 1961

OSTI ID:4048911

isserow, S; White, A M; Sawyer, H F; Jordan, E F; Larson, W L; Richmond, W J; Green, H M; Smoot, P R; Donaldson, A D; Gilman, A R; Tuffin, W B

Processing of the five outer tubes of the demonstration set and two earlier tubes was completed. It was noted that bowing is a more serious problem for these thin-walled tubes than for thick-walled tubes and is related to the slight non-uniformity of wall thickness. Considerable effort was expended in comparing cladding thickness measurements as determined by autoradiography with those obtained by eddy currert measurements. While not completely reconcilable, the two methods are not far apart. On several of the tubes, the thinnest cladding was not associated with the core end shape. Billets for a demonstratfon set of six inner tubes were assembled for extrusion. The billet design was similar to that used for satisfactory Tubes 103, 104 and 105 except that the core length was increased slightly. Autoradiography results for unalloyed Vallecitos Tube No. 114 caused some doubt as to the adequacy of the cladding thickness at some locations. Tube 114 was fully processed and will be re-autoradiographed in about two months to resolve whether the apparent thin spots were caused by radioactive decay products. Additional bend tests, conducted while recording the load-deformation curves, indicated that the shapes of the curves are not influenced by the mode of fracture. It appeared that the mode of fracture of U-- 2 wt.% Zr specimens is not entirely similar to that of U--1 wt.% Si but characterized also by some of the features of the failure mechanism of U--1.5 wt.% Mo specimens. A brittle core, even with a ductile interface (as for beta treated U--1 wt.% Si specimens), caused the most brittle failures. A brittle diffusion zone (as for diffusion heat treated U--2 wt.% Zr specimens) caused less loss of ductility. For the preparation of capsule specimens of various compositions, a satisfactory coextrusion was made with a low-carbon U--1 wt.% Si core, a satisfactory core was prepared and a billet assembled for coextrusion of specimens with unalloyed dingot uranium cores, and progress was made in determining the heat treatments for U--0.3 wt.% Al--0.5 wt.% Si alloy and U--0.3 wt.% Cr-0.3 wt.% Mo alloys. In addition, a Zircaloy-4 tube was extruded for subsequent machining into end caps and the preparation of braze alloy is under way. After experimenting with various techniques, 24 magnesiumZircaloy-4 diffusion couples were prepared by melting magnesium around the Zircaloy-4. Subsequent solid state diffu sion at 300, 400, 500, and 600 deg C for various times will be determined by measuring the additional penetration. Attempts are being made to produce a casting of Mg--0.4 wt.% Si for use in making comparable diffusion couples. Significant progress was made in the construction of an apparatus for transient zone melting of tabular fuel elements. Laboratory experiments and examination of new tubular and rod extrusions have shed no additional light on the cause of irregularities at the interface on the outside surfaces of extruded stainless steel-Zircaloy joints. (For preceding period see NMI-7233.) (M.C.G.)

• Research Organization: Nuclear Metals, Inc., Concord, Mass.
• NSA Number: NSA-15-015289
• OSTI ID: 4048911
• Report Number(s): NMI-7234
• Country of Publication: United States
• Language: English

Related Subjects

ALUMINUM ALLOYS
BRITTLENESS
CANNING
CHROMIUM ALLOYS
DEFORMATION
DIFFUSION
DUCTILITY
EXTRUSION
FABRICATION
FUEL CANS
FUEL ELEMENTS
HIGH TEMPERATURE
JOINTS
MAGNESIUM
MEASURED VALUES
MELTING
MOLYBDENUM ALLOYS
RADIOGRAPHY
REACTOR TECHNOLOGY
REACTORS
SILICON
STAINLESS STEELS
THICKNESS
TUBES
URANIUM ALLOYS
ZIRCALOY
ZIRCONIUM ALLOYS