The rate of hydrogen release out of clean metallic surfaces

Ali-Khan, I.; Dietz, K.J.; Waelbroeck, F.; Wienhold, P.

doi:10.1016/0022-3115(78)90167-8

Cited by 162 publications

(43 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…At the completion of these tests, however, it was not known if the effect was real. Though a transition from diffusion-limited to surfacelimited permeation is known to occur in metals at low partial pressures [20][21][22][23][24][25] and might explain the lower values, there was some uncertainty about the measurements. Neither the primary loop tritium concentration nor the residual hydrogen concentrations were measured.…”

Section: Discussionmentioning

confidence: 95%

“…(cf. [20][21][22][23][24][25]). To investigate this, for FY-12 testing the system was modified to allow improved monitoring of both primary and secondary loops.…”

Section: Methodsmentioning

confidence: 99%

“…Provided that the secondary pressure of all isotopes in the secondary is small, the surface-limited regime is realizable, and the transition from surface-limited to diffusion-limited behavior is governed by a dimensionless number W. For a single isotope (say, hydrogen), W is given by [21] …”

Section: General Permeation Analysismentioning

confidence: 99%

See 2 more Smart Citations

Tritium Permeability of Incoloy 800H and Inconel 617

Winston¹,

Calderoni²,

Humrickhouse³

2012

View full text Add to dashboard Cite

Design of the Next Generation Nuclear Plant (NGNP) reactor and its hightemperature components requires information regarding the permeation of fission generated tritium and hydrogen product through candidate heat exchanger alloys. Release of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system represent safety basis and product contamination issues. Of the three potential candidates for high-temperature components of the NGNP reactor design, only permeability for Incoloy 800H has been well documented.To support engineering design of the NGNP reactor components, tritium permeability values for Inconel 617 and Incoloy 800H were determined in Fiscal Year 2011 using a measurement system designed and fabricated at Idaho National Laboratory. The measured tritium permeability of Incoloy 800H and Inconel 617 deviated substantially from the values measured for hydrogen. The experiments were repeated in FY-12 with Incoloy 800H using reconfigured tritium detection and in-process hydrogen measurement to reduce uncertainties from the first series of tests. The tritium permeability of Incoloy 800H was measured in the temperature range 700 to 950°C and at primary concentrations of 0.5 to 125 (atom) parts per million tritium in helium (partial pressures of 10 -7 atm) -four orders of magnitude lower partial pressure than used in the hydrogen permeation testing. The new data provide some evidence that permeation has become surface-limited, as expected for sufficiently low pressures. In this case, the resultant tritium flux is linearly related to the pressure, unlike the diffusionlimited (high pressure) regime, in which it is proportional to the square root of pressure. In the surface-limited regime, the proportionality constant is not the permeability K, but the dissociation rate constant K d . Since the present measurements appear to span at least a part of the transition region between these two extremes, a quantitative estimate of K d could not be obtained, but the theory and experimental requirements for doing so are outlined. vi vii

show abstract

Section: Discussionmentioning

confidence: 95%

“…(cf. [20][21][22][23][24][25]). To investigate this, for FY-12 testing the system was modified to allow improved monitoring of both primary and secondary loops.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Tritium Permeability of Incoloy 800H and Inconel 617

Winston¹,

Calderoni²,

Humrickhouse³

2012

View full text Add to dashboard Cite

show abstract

“…The rate of evolution of hydrogen from a surface is dependent on the first power of the concentration if diffusion in the wall to the surface,is rate controlling [3] If recombination is rate controlling, q . = o K c 2 [3], where a is a surface roughness factor and K r is the recombination coefficient.…”

Section: Data Inmentioning

confidence: 99%

“…Although the general nature of recycling has been modeled [1,2] and much experimental information exists concerning the various physical processes involved [3,4], there continues to be a need to determine which processes are most important, i.e., rate controlling in a particular circumstance. We [5,6] and others [7] have shown that surface composition and temperature are very important parameters for technical surfaces.…”

Section: Introductionmentioning

confidence: 99%

Studies of mechanisms of hydrogen recycle using a plasma-wall interaction experiment

Clausing

Emerson

Heatherly

1980

Journal of Nuclear Materials

View full text Add to dashboard Cite

It is shown that for type 304L stainless steel at room temperature and ion energies of 100 eV a large part of the recycling occurs with hydrogen residence times in the wall of about 100 ms. The use of wall temperatures from 80 to 500 K permits differentiation between thermally activated processes and ion bombardment-induced phenomena. For low energy ions (100 eV) onto 300 K stainless steel walls recycling increases to more than 90% in a few tenths of a second at 3 * 10 16 ions cm" 2 s" 1 . For ions up to 300 eV at this flux there is little energy dependence. Both thermally and ion induced processes can be important at room temperature, but under the conditions of this study thermal processes greatly enhance the recycle rates at 300 and 500 K. Preliminary results indicate that recombination of atomic hydrogen to molecular hydrogen can be rate controlling in some practical regimes.

show abstract