High Hydrogen Concentrations Detected In The Underground Vaults For RH-TRU Waste At INEEL Compared With Calculated Values Using The INEEL-Developed Computer Code
About 700 remote-handled transuranic (RH-TRU) waste drums are stored in about 144 underground vaults at the Intermediate-Level Transuranic Storage Facility at the Idaho National Environmental and Engineering Laboratory’s (INEEL’s) Radioactive Waste Management Complex (RWMC). These drums were shipped to the INEEL from 1976 through 1996. During recent monitoring, concentrations of hydrogen were found to be in excess of lower explosive limits. The hydrogen concentration in one vault was detected to be as high as 18% (by volume). This condition required evaluation of the safety basis for the facility. The INEEL has developed a computer program to estimate the hydrogen gas generation as a function of time and diffusion through a series of layers (volumes), with a maximum five layers plus a sink/environment. The program solves the first-order diffusion equations as a function of time. The current version of the code is more flexible in terms of user input. The program allows the user to estimate hydrogen concentrations in the different layers of a configuration and then change the configuration after a given time; e.g.; installation of a filter on an unvented drum or placed in a vault or in a shipping cask. The code has been used to predict vault concentrations and to identify potential problems during retrieval and aboveground storage. The code has generally predicted higher hydrogen concentrations than the measured values, particularly for the drums older than 20 year, which could be due to uncertainty and conservative assumptions in drum age, heat generation rate, hydrogen generation rate, Geff, and diffusion rates through the layers.
- Research Organization:
- Idaho Completion Project (ICP)
- Sponsoring Organization:
- DOE - EM
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 911045
- Report Number(s):
- ICP/CON-04-00563; TRN: US0704359
- Resource Relation:
- Conference: Waste Management Symposium 05,Tuscon, Arizona,02/27/2005,03/03/2005
- Country of Publication:
- United States
- Language:
- English
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