Feasibility of gas-phase decontamination of gaseous diffusion equipment

Technical Report · Mon Feb 01 04:00:00 EST 1993

OSTI ID:6645855

Munday, E B; Simmons, D W

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.

• Research Organization: Oak Ridge Gaseous Diffusion Plant, TN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OT21400
• OSTI ID: 6645855
• Report Number(s): K/TCD-1048; ON: DE93009793
• Country of Publication: United States
• Language: English

Related Subjects

050500* -- Nuclear Fuels-- Uranium Enrichment
054000 -- Nuclear Fuels-- Health & Safety
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ACTINIDE COMPOUNDS
ACTINIDES
CLEANING
COMPRESSORS
CONTROL EQUIPMENT
COPPER
DECOMMISSIONING
DECONTAMINATION
ELEMENTS
EQUIPMENT
FEASIBILITY STUDIES
FLOW REGULATORS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASEOUS DIFFUSION PLANTS
GASES
HALIDES
HALOGEN COMPOUNDS
INDUSTRIAL PLANTS
ISOTOPE SEPARATION PLANTS
MANAGEMENT
MATERIALS RECOVERY
METALS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
ORGDP
PADUCAH PLANT
PIPES
PORTSMOUTH GASEOUS DIFFUSION PLANT
PROCESSING
PUMPS
REMEDIAL ACTION
TRANSITION ELEMENTS
URANIUM
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM HEXAFLUORIDE
URANYL COMPOUNDS
URANYL FLUORIDES
US AEC
US DOE
US ERDA
US ORGANIZATIONS
VALVES
WASTE MANAGEMENT
WASTE PROCESSING