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Title: Feasibility of gas-phase decontamination of gaseous diffusion equipment

Abstract

The five buildings at the K-25 Site formerly involved in the gaseous diffusion process contain 5000 gaseous diffusion stages as well as support facilities that are internally contaminated with uranium deposits. The gaseous diffusion facilities located at the Portsmouth Gaseous Diffusion Plant and the Paducah Gaseous Diffusion Plant also contain similar equipment and will eventually close. The decontamination of these facilities will require the most cost-effective technology consistent with the criticality, health physics, industrial hygiene, and environmental concerns; the technology must keep exposures to hazardous substances to levels as low as reasonably achievable (ALARA). This report documents recent laboratory experiments that were conducted to determine the feasibility of gas-phase decontamination of the internal surfaces of the gaseous diffusion equipment that is contaminated with uranium deposits. A gaseous fluorinating agent is used to fluorinate the solid uranium deposits to gaseous uranium hexafluoride (UF{sub 6}), which can be recovered by chemical trapping or freezing. The lab results regarding the feasibility of the gas-phase process are encouraging. These results especially showed promise for a novel decontamination approach called the long-term, low-temperature (LTLT) process. In the LTLT process: The equipment is rendered leak tight, evacuated, leak tested, and pretreated, charged with chlorine trifluoride (ClF{submore » 3}) to subatmospheric pressure, left for an extended period, possibly > 4 months, while processing other items. Then the UF{sub 6} and other gases are evacuated. The UF{sub 6} is recovered by chemical trapping. The lab results demonstrated that ClF{sub 3} gas at subatmospheric pressure and at {approx} 75{degree}F is capable of volatilizing heavy deposits of uranyl fluoride from copper metal surfaces sufficiently that the remaining radioactive emissions are below limits.« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge Gaseous Diffusion Plant, TN (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10139310
Report Number(s):
K/TCD-1048
ON: DE93009793
DOE Contract Number:  
AC05-84OT21400
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Feb 1993
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; GASEOUS DIFFUSION PLANTS; DECOMMISSIONING; URANIUM HEXAFLUORIDE; MATERIALS RECOVERY; EQUIPMENT; DECONTAMINATION; PORTSMOUTH GASEOUS DIFFUSION PLANT; PADUCAH PLANT; URANYL FLUORIDES; COPPER; COMPRESSORS; VALVES; PUMPS; PIPES; URANIUM; FEASIBILITY STUDIES; GASES; ORGDP; REMEDIAL ACTION; 050500; 054000; URANIUM ENRICHMENT; HEALTH AND SAFETY

Citation Formats

Munday, E B, and Simmons, D W. Feasibility of gas-phase decontamination of gaseous diffusion equipment. United States: N. p., 1993. Web. doi:10.2172/10139310.
Munday, E B, & Simmons, D W. Feasibility of gas-phase decontamination of gaseous diffusion equipment. United States. https://doi.org/10.2172/10139310
Munday, E B, and Simmons, D W. 1993. "Feasibility of gas-phase decontamination of gaseous diffusion equipment". United States. https://doi.org/10.2172/10139310. https://www.osti.gov/servlets/purl/10139310.
@article{osti_10139310,
title = {Feasibility of gas-phase decontamination of gaseous diffusion equipment},
author = {Munday, E B and Simmons, D W},
abstractNote = {The five buildings at the K-25 Site formerly involved in the gaseous diffusion process contain 5000 gaseous diffusion stages as well as support facilities that are internally contaminated with uranium deposits. The gaseous diffusion facilities located at the Portsmouth Gaseous Diffusion Plant and the Paducah Gaseous Diffusion Plant also contain similar equipment and will eventually close. The decontamination of these facilities will require the most cost-effective technology consistent with the criticality, health physics, industrial hygiene, and environmental concerns; the technology must keep exposures to hazardous substances to levels as low as reasonably achievable (ALARA). This report documents recent laboratory experiments that were conducted to determine the feasibility of gas-phase decontamination of the internal surfaces of the gaseous diffusion equipment that is contaminated with uranium deposits. A gaseous fluorinating agent is used to fluorinate the solid uranium deposits to gaseous uranium hexafluoride (UF{sub 6}), which can be recovered by chemical trapping or freezing. The lab results regarding the feasibility of the gas-phase process are encouraging. These results especially showed promise for a novel decontamination approach called the long-term, low-temperature (LTLT) process. In the LTLT process: The equipment is rendered leak tight, evacuated, leak tested, and pretreated, charged with chlorine trifluoride (ClF{sub 3}) to subatmospheric pressure, left for an extended period, possibly > 4 months, while processing other items. Then the UF{sub 6} and other gases are evacuated. The UF{sub 6} is recovered by chemical trapping. The lab results demonstrated that ClF{sub 3} gas at subatmospheric pressure and at {approx} 75{degree}F is capable of volatilizing heavy deposits of uranyl fluoride from copper metal surfaces sufficiently that the remaining radioactive emissions are below limits.},
doi = {10.2172/10139310},
url = {https://www.osti.gov/biblio/10139310}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 01 00:00:00 EST 1993},
month = {Mon Feb 01 00:00:00 EST 1993}
}