POWER REACTOR PROGRAM. Progress Report to Savannah River Operations Office, United States Atomic Energy Commission for the Period April 1, 1962-April 30, 1962
Two outer HWCTR tubes containing U-1 wt% Si and U1.5 wt % Mo cores were extruded. The U-1 wt % Si tube will be processed as a full length tube with integral end seals. The U-1.5 wt% Mo tube will be used to obtain short irradiation specimens with brazed end seals. Studies of several dilute U alloys were continued in the program to develop a fuel with improved irradiation behavior at high temperatures. A suitable heat treatment of billet-sized sections of U-0.3 wi% Al-0.18 wt% Si has yet to be developed. Additional stability tests of U-0.08 wt% Si in the beta-quenched condition show that the room temperature hardness is not sensitive to aging at 600 deg C, but the elevated temperature hardnesses are markedly reduced within 8 hours. The softening is consistent with changes in the microstructure. Uranium containing 350 ppm Fe, 1000 ppm Al, and 700 ppm C was included in this program, in light of the British observation that such an alloy in the cast condition has improved resistance to swelling. Experimental extrusions of this alloy have demonstrated that a process resembling she upset-extrude sequence has to be used to ensure smooth core-cladding interfaces. The alloy content does not raise the extrusion constant significantly at 1100 deg F. Beta quenching of the extruded alloy produces fine grain size, and a fine precipitate is formed uniformly through the matrix; apparently oil quenching does not suppress the precipitation of the alloy content. Hot hardness testing of extruded specimens of the U-- Fe-Al alloy that was beta quenched and then aged at 60O deg C for 1, 24, and 100 hours shows that the maximum elevated temperature hardness is obtained in the beta-quenched condition. Aging at 600 deg C causes significant decreases in hardnesses; the maximum reduction of hardness has already occurred after only 24 hours. Evaluation of extruded tube sections of ingot and dingot U containing additions of Fe, Si, and/or Al to 100--150 ppm showed that these additions markedly affect the properties of U. The hardness of U in the beta-quenched condition is increased as much as 50% in the 200 to 600 deg C range; however, annealing at 600 deg C completely erases this effect. It is believed that this hardness behavior results from dispersion hardening rather than solution hardening. The dispersed phase may be related to the delta phase'' that is used for control of grain size. The very dilute alloy additions also retard recrystallization in both the ingot and dingot U. The effects of subtle differences in composition and heat treatment (such as beta treatment) may be related to the reported differences in irradiation behavior of unalloyed U.'' (auth)
- Research Organization:
- Nuclear Metals, Inc., Concord, Mass.
- DOE Contract Number:
- AT(30-1)-1565
- NSA Number:
- NSA-16-030086
- OSTI ID:
- 4771904
- Report Number(s):
- NMI-7250
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- United States
- Language:
- English
Similar Records
POWER REACTOR PROGRAM. Progress Report to Savannah River Operations Office, United States Atomic Energy Commission for the Period August 1, 1962-August 31, 1962
POWER REACTOR PROGRAM. Progress Report to Savannah River Operations Office, United States Atomic Energy Commission for the Period October 1, 1962 through October 31, 1962
Related Subjects
ALUMINUM
ALUMINUM ALLOYS
ANNEALING
BRAZING
CARBON
DEFORMATION
DISPERSIONS
EXTRUSION
FABRICATION
FUEL ELEMENTS
GRAIN SIZE
HARDNESS
HEAT TREATMENTS
HEAVY WATER MODERATOR
HIGH TEMPERATURE
HWCTR
IMPURITIES
IRON
IRON ALLOYS
IRRADIATION
LATTICES
MATERIALS TESTING
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
PERFORMANCE
PHASE DIAGRAMS
POWER PLANTS
PRECIPITATION
QUANTITY RATIO
REACTORS
RECRYSTALLIZATION
SEALS
SILICIDES
STABILITY
TUBES
URANIUM ALLOYS