MOLTEN-SALT REACTOR PROGRAM QUARTERLY PROGRESS REPORT FOR PERIODS ENDING JANUARY 31 AND APRIL 30, 1960
Engineering and Component Development. Tests of molten-salt-lubricated hydrodynamic bearings continued in bearing-test rigs and in the sump type centrifugal pumps. The small frozen-lead-sealed centrifugal pump has circulated molten salt continuously at 1200 deg F for 16,500 hr. Molten salt was circulated at 1200 deg F in the Remotemaintenance Development Facility. Twenty-five forcedcirculation corrosion loops were placed in operation in the MSR corrosion program. A frozen-salt-sealed graphite-tometal joint was tested. The enthalpy of the BULT-14 mixture (LiF--BeF/sub 2/-- UF/sub 4/--ThF/sub 4/) was determined for the temperature range 100 to 800 deg C. The thermal conductivity for an INOR- 8 rod specimen was experimentally established up to a temperature of 900 deg F. The surface tension of a NaF--ReF/sub 2/ mixture was measured for the range 600 to 800 deg C. Additional data were obtained for heat transfer to BULT-14 flowing within heated Inconel and INOR-8 tubes. Materials Studies. Examinations of ninc INOR-8 thermalconvection loops, which operated with fused fluoride mixtures for one year, were completed. Seven Inconel thermalconvection loops were also examined, all of which showed attack in the form of intergranular voids to depths ranging from 4 to 15 mils. Examinations of four Inconel forcedconvection loops, which operated for different periods with fluoride salt of the LiF--BeF-- UF/sub 4/ system, revealed heavy subsurface-void formation in regions where loop wall temperatures exceeded 1200 deg F. Metallographic examinations were completed on three INOR-8 forced-convection loops which operated with fluoride mixtures for periods of 1 year or longer; with the exception of one loop, negligible attack was found. Chemical and metallographic examinations were carried out to investigate the thin corrosion film which has appeared in a majority of the long- term INOR-8 corrosion loops. The 48% Ti--48% Zr--4% Be alloy was used to braze an assembly of graphite tubes to an INOR-8 header in order to demonstrate the feasibility of fabricating such an assembly. Alloys in the Au--Ni--Ta and Au--Ni- -Mo ternary systems, which are resistant to corrosion by molten fluorides and which may be useful in certain applications, are under study for brazing graphiteto-graphite and graphite-to-molybdenum joints. Thinty-one different grades of graphite were tested for their resistance to permeation by molten fluorides in 100-hr screening tests at 1300 deg F and pressures of 150 psig. Two tests were conducted to remove from graphite the oxygen contamination that causes a portion of the uraaium of LiF--BeF/sub 2/--UF/sub 4/ (fuel 130) to precipitate as UO/sub 2/ when this fuel is exposed to the graphite at 1300 deg F in a vacuum. INOR-8 was carburized to a depth of 14 mils while in direct contact for 3400 hr with grade TSF graphite at 1000 psi in NaF--ZrF/sub 4/-UF/sub 4/ (fuel 30) at 1300 deg F. Three nickel-base brazing alloys showed good corrosion resistance to fuel 130 at 1300 deg F during a 10,000-hr thermal-convection loop test of INOR-8 joints. According to preliminary checks on phase behavior, the substiiution or addition of ZrF/sub 4/ in LiF--BeF/sub 2/ fuels containing UF/sub 4/ and ThF/sub 4/ appears to provide a feasible route to potential improvements in corrosion behavior and perhaps oxide tolerance while at the same time retaining favorable inventories and physical properties. Selective precipitation of oxides continues to appear promising as a means of processing breeder fuels to remove protactinium and uranium from fiuoride melts. Solutions of NO/sub 2/ in liquid anhydrous hydrogen fluoride appear attractive as an alternative to HF--H/sub 2/O solutions for processing MSR fuel salt containing little or no thorium. In a single experiment no protactinium was removed from MSR blanket salt by fluorination at 650 deg C. (For preceding period see ORNL2890.) (W.L.H.)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-14-025862
- OSTI ID:
- 4142523
- Report Number(s):
- ORNL-2973
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- United States
- Language:
- English
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MOLTEN-SALT REACTOR PROGRAM QUARTERLY PROGRESS REPORT FOR PERIOD ENDING JULY 31, 1959
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