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Title: Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns

Abstract

Through radiolytic and thermolytic reactions, Hanford tank wastes generate and retain a variety of gases, including hydrogen, nitrous oxide, methane (and other hydrocarbons), ammonia, and nitrogen. This gas generation can be expected to continue during processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The generation rates in the WTP will change from those for the in-situ tank waste because of different process temperatures, different dose rates produced by in-process changes in the proportions of solid and liquid, and dilution of the waste liquid. The flammability of the generated gas that is continuously released, and of any retained gas that might be released into a vessel headspace in quantity due to a spontaneous release, depends on the concentrations not only of the fuel gases—primarily hydrogen (H2), methane, other hydrocarbons, and ammonia—but of the oxidizer nitrous oxide (N2O). As a result of high concentrations of N2O, some gas mixtures are “self-flammable” (i.e., ignition can occur when no air is present because N2O provides the only oxidizer needed). Self-flammability could potentially reduce the effectiveness of using a nitrogen (N2) purge in the headspace as a flammability control, if its effects are not accounted for. A given amount of inertant gasmore » (N2) can accommodate only a certain amount of a generated self-flammable gas before the mixture with inertant gas becomes flammable.« less

Authors:
 [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1349993
Report Number(s):
PNNL-24194 Rev. 1
830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES

Citation Formats

Mahoney, Lenna A. Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns. United States: N. p., 2015. Web. doi:10.2172/1349993.
Mahoney, Lenna A. Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns. United States. https://doi.org/10.2172/1349993
Mahoney, Lenna A. 2015. "Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns". United States. https://doi.org/10.2172/1349993. https://www.osti.gov/servlets/purl/1349993.
@article{osti_1349993,
title = {Self-Flammability of Gases Generated by Hanford Tank Waste and the Potential of Nitrogen Inerting to Eliminate Flammability Safety Concerns},
author = {Mahoney, Lenna A.},
abstractNote = {Through radiolytic and thermolytic reactions, Hanford tank wastes generate and retain a variety of gases, including hydrogen, nitrous oxide, methane (and other hydrocarbons), ammonia, and nitrogen. This gas generation can be expected to continue during processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The generation rates in the WTP will change from those for the in-situ tank waste because of different process temperatures, different dose rates produced by in-process changes in the proportions of solid and liquid, and dilution of the waste liquid. The flammability of the generated gas that is continuously released, and of any retained gas that might be released into a vessel headspace in quantity due to a spontaneous release, depends on the concentrations not only of the fuel gases—primarily hydrogen (H2), methane, other hydrocarbons, and ammonia—but of the oxidizer nitrous oxide (N2O). As a result of high concentrations of N2O, some gas mixtures are “self-flammable” (i.e., ignition can occur when no air is present because N2O provides the only oxidizer needed). Self-flammability could potentially reduce the effectiveness of using a nitrogen (N2) purge in the headspace as a flammability control, if its effects are not accounted for. A given amount of inertant gas (N2) can accommodate only a certain amount of a generated self-flammable gas before the mixture with inertant gas becomes flammable.},
doi = {10.2172/1349993},
url = {https://www.osti.gov/biblio/1349993}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 12 00:00:00 EDT 2015},
month = {Mon Oct 12 00:00:00 EDT 2015}
}