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Latest News
What’s the most difficult question you’ve been asked as a maintenance instructor?
Blye Widmar
"Where are the prints?!"
This was the final question in an onslaught of verbal feedback, comments, and critiques I received from my students back in 2019. I had two years of instructor experience and was teaching a class that had been meticulously rehearsed in preparation for an accreditation visit. I knew the training material well and transferred that knowledge effectively enough for all the students to pass the class. As we wrapped up, I asked the students how they felt about my first big system-level class, and they did not hold back.
“Why was the exam from memory when we don’t work from memory in the plant?” “Why didn’t we refer to the vendor documents?” “Why didn’t we practice more on the mock-up?” And so on.
G. A Esteban, F. Legarda, A. Perujo
Fusion Science and Technology | Volume 48 | Number 1 | July-August 2005 | Pages 617-620
Technical Paper | Tritium Science and Technology - Materials Interaction and Permeation | doi.org/10.13182/FST05-A1001
Articles are hosted by Taylor and Francis Online.
A time-dependent gas-phase absorption-desorption technique has been used to evaluate the isotope effect on the diffusive transport parameters of hydrogen isotopes in polycrystalline tungsten and the reduced activation ferritic-martensitic steel OPTIFER-IVb.Experiments have been run with both protium and deuterium obtaining their respective transport parameters of diffusivity (D), Sieverts' constant (Ks), the trap site density (Nt) and the trapping activation energy (Et). Isotope effects on these transport parameters are analysed and modelled. Because the classical isotope relation for diffusivity has not been fulfilled, quantum-statistical vibration theory has been applied to model the isotopic relation. The hydrogen vibration properties description in a metallic-host lattice allows deriving more accurate tritium transport parameters. A congruent isotopic variation of diffusion parameters related to the type of crystal structure, bcc, has been confirmed.
