ALPHA PHASE VACUUM OUTGASSING OF DINGOT URANIUM
Technical Report
·
OSTI ID:4842808
A detailed description is given of the theory and practice that was developed for the control of hydrogen in dingot uranium metal by vacuum outgassing of fuel core blanks at an intermediate alpha phase temperature. Vacuum extraction procedures for hydrogen analysis are reported, with evidence of maximum precision in the use of Toepler pumps and a palladium membrane. Determinations of hydrogen diffusion rates have shown that the diffusion coefficient for the gamma phase is uninfluenced by carbon and hydrogen contents, that in the beta and alpha phases the true diffusivity can be measured only at low carbon and hydrogen levels. Apparent diffusion coefficients, materially lower than true diffusivities, are observed in outgassing high-hydrogen dingot metal or highcarbon ingot uranium. The dependence of apparent diffusivity on outgassing temperature and initial hydrogen content of dingot metal is expressed mathematically for use in calculating plant outgassing furnce cycles. The estimation of necessary time at the outgassing temperature is illustrated for a number of conditions of core black geometry and degree of desired hydrogen removal. A maxium permissible outgassing temperature of 950 deg F is defined by evidence of metallographic grain coarsening in core blanks beta treated after vacuum outgassing at higher alpha phase temperatures. Studies of outgassing after beta treatment are also presented, giving the temperature ranges to be used, depending on whether recrystallization by annealing is to be sought or avoided. The experience in Plant outgassing operations is quoted with the aid of histograms. Effective outgassing is shown to be favored when an accurate knowledge of apparent diffusivity is available and when the cross section of the core blanks is small, as in hollow shapes. (auth)
- Research Organization:
- Mallinckrodt Chemical Works. Uranium Div., Weldon Spring, Mo.
- NSA Number:
- NSA-15-029627
- OSTI ID:
- 4842808
- Report Number(s):
- MCW-1467
- Country of Publication:
- United States
- Language:
- English
Similar Records
PROCESS DEVELOPMENT QUARTERLY PROGRESS REPORT, OCTOBER-DECEMBER 1960
RECRYSTALLIZATION OF BETA-HEAT-TREATED DINGOT-URANIUM CORES. Topical Report
Status of alloyed dingot program, January 1963
Technical Report
·
Tue Jan 31 23:00:00 EST 1961
·
OSTI ID:4061331
RECRYSTALLIZATION OF BETA-HEAT-TREATED DINGOT-URANIUM CORES. Topical Report
Technical Report
·
Fri Aug 24 00:00:00 EDT 1962
·
OSTI ID:4792031
Status of alloyed dingot program, January 1963
Technical Report
·
Thu Jan 10 23:00:00 EST 1963
·
OSTI ID:10175105