IN-PILE LOOP INVESTIGATIONS OF CORROSION OF ZIRCALOY-2 AND OTHER POSSIBLE REACTOR MATERIALS IN 0.04m UO$sub 2$SO$sub 4$ AT 280 C

Technical Report · Tue May 01 00:00:00 EDT 1962

OSTI ID:4842060

Jenks, G H; Baker, J E

6 9 4 9 ; 3 L-2-1O was one of a series de signed to test the radiation corrosion of Zircaloy-2 and other possible reactor construction materials in UO/sub 2/SO/sub 4/ solutions under various radiation intensities, temperatures, solution compositions, and velocities of flow past specimens. The solution employed was 0.04 M UO/sub 2/SO/sub 4/, 0.0075 M CuSO/sub 4/, and 0.02 M H/sub 2/SO/sub 4/ in H/sub 2/O. Radiation exposure was carried out in the LITR HB-2 facility, at a main-stream temperature of 280 deg C. Construction material for the loop was type 347 stainless steel. Specimens of Zircaloy-2, Ti55A, platinum, and types 347 and 309 SCb stainless steel were tested. The power density at core specimens ranged from a maximum of 4.2 to a minimum of 0.8 w/mi. The total time of high-temperature operation with UO/sub 2/SO/sub 4/ solutions was 1872 hr, of which 1672 hr was with enriched UO/sub 2/SO/sub 4/. In-pile circulation time for this experiment (following the initial reactor startup) was 1456 hr, and the reactor energy was 3765 Mwhr, with most of the energy accumulated at the 3-Mw power level. The over-all corrosion rate of steel in the loop decreased slightly with time of exposure. The average over-all steel rate based on oxygen data and radiation time was 0.47 mpy (mils per year). The average rate based on nickel data was less than 0.3 mpy, but the nickel results are believed to be low because of sorption of this material on corrosion product oxides. The average and maximum rates for type 347 stainless steel channel specimens outside the core were 0.18 and 0.45 mpy, based on weight loss data, exposedarea attack, and radiation time. The comparably determined minimum and maximum rates for channel specimens in the core ranged from 0.1 to 2.8 mpy, with the rate increasing in an apparently regular fashion with increasing power density above about 2 w/ml. Below this power, the rates were about the same as those observed in-line. There was no apparent effect of varying solution velocities in the range 10 to 40 fps on either the core channel or in-line channel specimens. Specimens of types 347 and 309 SCb stainless steel exposed on one assembly in the core annulus region corroded at much higher rates than core channel specimens, but annulus steel specimens on another similar array corroded at somewhat lower rates than the channel specimens. The explanation for this difference is unknown. Differences in galvanic action between the specimens located on each of the assemblies is considered the most likely explanation, but no detailed mechanism is suggested. Zircaioy-2 corrosion results from this loop are discussed and correIated elsewhere in terms of the 280 deg C relationship between corrosion rate R (mpy), power density P (w/nfl), and uranium sorption factor alpha : I/R = 2.23/P alpha + 1/40. The data from this experiment obey this relationship. The value of alpha for core annulus specimens, which were exposed to a velocity of about 0.8 fps, was 6.9. For the exposed surfaces of those channel specimens located in the convergent section of the channel and exposed to average velocities of 19 and 33 fps, the best estimates of alpha are in the range l to 1.8. Specimens located in the divergent section of the channel exhibited higher alpha values. Results for Ti-55A specimens indicated that in- pile titanium corrosion was affected by some uniform change in the solution under radiation to a greater extent than by fission recoil irradiation of specimen surfaces or by the fissioning taking place in the solution immediately adjacent to specimens. However, the result obtained with one core specimen exposed to the highest average solution velocity (35 fps) suggested that the susceptibility of this material to adverse velocity effects is increased by exposure to fissioning solution. With the exception of this one specimen, the average rate (based on radiation time and total area) for core channel speci

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-16-017982
• OSTI ID: 4842060
• Report Number(s): ORNL-2962
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: United States
• Language: English

Related Subjects

METALS, CERAMICS, AND OTHER MATERIALS
ADSORPTION
COPPER SULFATES
CORROSION
IN PILE LOOPS
MATERIALS TESTING
NICKEL ALLOYS
NIOBIUM ALLOYS
OXYGEN
PLATINUM
RADIATIONS
REACTION KINETICS
SOLUTIONS
STAINLESS STEELS
SULFATES
SULFURIC ACID
TEMPERATURE
TITANIUM ALLOYS
URANIUM
URANYL COMPOUNDS
VELOCITY
WATER
ZIRCALOY