Tritium permeability and pressure dependence of 304l stainless steel in the temperature range 723 to 1023 k
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Tritium Permeability and Pressure Dependence of 304L Stainless Steel in theTemperature Range 723 to 1023 K MASAO MATSUYAMA and J. D. REDMAN
Fig. 7--Stereographic projection for the Pitsch orientation relationship showing great circles of possible diffraction spots from the phase when observed on (001) fcc zones.
The author acknowledges the help of D. Miracle of this laboratory in the chemical identification of particles by EPMA. REFERENCES 1. Z. Nishiyama: Scien. Rep., Tokohu University, 1934, vol. 23, p. 638. 2. G. Wasserman: Arch. fur das Eisenhiitt, 1933, vol. 16, p. 347. 3. W. Pitsch: Phil. Mag., 1959, vol. 4, p. 577. 4. M.G. Hall, H.I. Aaronson, and K. R. Kinsman: Surface Sci., 1972, vol. 31, p. 257.
Knowledge of tritium permeability is important to the development of the nuclear fission and the thermonuclear reactor systems. Numerous investigations concerning the permeability and diffusivity of hydrogen isotopes for various metals and alloys have been reported. ~-* In recent papers, it has been reported that oxide layers formed on the surfaces of alloys markedly affected the permeation of tritium, 5'6 and also that both the permeability constant and the activation energy for tritium permeation were different for nonoxidized austenitic steels and ferritic steels. 7 Tritium permeation through 304L stainless steel, which has one of the lowest nickel and carbon contents of the austenitic steels, had not been measured and was the subject of the present study. The characteristics of the 304L specimen used are given in Table I. The experimental apparatus and techniques were described elsewhere, s and only a brief description follows. In an all-metal apparatus, initially, purified normal hydrogen is flowed over both the outside and inside surfaces of the tubular specimen which is enclosed in a chamber that is heated by a tube furnace. The surfaces of the specimen had been cleaned by electropolishing and then coated on both sides with a 7.62/xm cladding of nickel by an electroplating method. Since permeation rates are controlled by diffusion rates through the bulk material, this thin nickel coating should cause no observable effect on the permeation rate for this sample. The specimen is contacted with the flowing hydrogen at approximately 423 K for four days to remove sorbed water. During permeation measurements, the hydrogen stream flowing along the outer surface also contained MASAO MATSUYAMA is with Tritium Research Center, Toyama University, Gofuku 3190, Toyama 930, Japan. J.D. REDMAN is on the Research Staff, Chemistry Division, Oak Ridge National Laboratory, R O. Box X, Oak Ridge, TN 37830. Manuscript submitted July 19, 1982.
498--VOLUME 14A, MARCH 1983
ISSN 0360-2133/83/0311-0498500.75/0 9 1983AMERICANSOCIETYFOR METALSAND THE METALLURGICALSOCIETYOF AIME
METALLURGICALTRANSACTIONSA
PRESSURE (Torr)
Table I. Characteristics of the 304L Stainless Steel Specimen Used in the Present Study
3 x 10-~4 5 x I0 -~I
t
Length: 25.4 cm I. D.: 1.27 cm; O. D.: 1.90 cm Thickness: 0.318 cm Mean Area: 126 cm2 Compositio
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