# Effect of vacuum core boundary conditions on separation in the gas centrifuge

## Abstract

A vacuum exists in the central region of the cylindrical rotor of a high-speed countercurrent gas centrifuge when operated with UF/sub 6/ for the enrichment of uranium. Since solutions of the Navier-Stokes equation are used to determine the isotopic distribution in the rotor, the location of the vacuum core boundary has a direct effect on the predicted separative work of the gas centrifuge. Because criteria for terminating the continuum region based on the Knudsen number are somewhat arbitrary, an approximate model developed by Onsager, which yields an analytical solution, has been used to evaluate the location of the boundary of the vacuum core more correctly. The results show that the location of this ''top of the atmosphere,'' in density scale heights, changes with the peripheral speed of the centrifuge. Using this location in the calculation of separation performance parameters of the gas centrifuge reduces, at the higher peripheral speeds, the contribution of axial diffusion to the effective stage length of a theoretical stage in the centrifuge. The correction due to imposing the top of the atmosphere limitation on axial diffusion becomes significant at high speeds and low countercurrent circulation rates.

- Authors:

- Publication Date:

- Research Org.:
- Oak Ridge Gaseous Diffusion Plant, Union Carbide Corporation, Nuclear Division, Oak Ridge, Tennessee 37830

- OSTI Identifier:
- 5165810

- DOE Contract Number:
- AC05-82OR20900; W-7405-ENG-26

- Resource Type:
- Journal Article

- Journal Name:
- Nucl. Technol.; (United States)

- Additional Journal Information:
- Journal Volume: 62:3

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; GAS CENTRIFUGES; BOUNDARY CONDITIONS; PERFORMANCE; GAS CENTRIFUGATION; NAVIER-STOKES EQUATIONS; ROTORS; URANIUM 235; URANIUM HEXAFLUORIDE; ACTINIDE COMPOUNDS; ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALPHA DECAY RADIOISOTOPES; CENTRIFUGATION; CENTRIFUGES; CONCENTRATORS; DIFFERENTIAL EQUATIONS; EQUATIONS; EVEN-ODD NUCLEI; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; HEAVY NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPE SEPARATION; ISOTOPES; MINUTES LIVING RADIOISOTOPES; NUCLEI; PARTIAL DIFFERENTIAL EQUATIONS; RADIOISOTOPES; SEPARATION PROCESSES; URANIUM COMPOUNDS; URANIUM FLUORIDES; URANIUM ISOTOPES; YEARS LIVING RADIOISOTOPES; 050502* - Nuclear Fuels- Uranium Enrichment- Centrifugation- (-1989)

### Citation Formats

```
Halle, E, Lowry, R A, and Wood, H G.
```*Effect of vacuum core boundary conditions on separation in the gas centrifuge*. United States: N. p., 1983.
Web.

```
Halle, E, Lowry, R A, & Wood, H G.
```*Effect of vacuum core boundary conditions on separation in the gas centrifuge*. United States.

```
Halle, E, Lowry, R A, and Wood, H G. Thu .
"Effect of vacuum core boundary conditions on separation in the gas centrifuge". United States.
```

```
@article{osti_5165810,
```

title = {Effect of vacuum core boundary conditions on separation in the gas centrifuge},

author = {Halle, E and Lowry, R A and Wood, H G},

abstractNote = {A vacuum exists in the central region of the cylindrical rotor of a high-speed countercurrent gas centrifuge when operated with UF/sub 6/ for the enrichment of uranium. Since solutions of the Navier-Stokes equation are used to determine the isotopic distribution in the rotor, the location of the vacuum core boundary has a direct effect on the predicted separative work of the gas centrifuge. Because criteria for terminating the continuum region based on the Knudsen number are somewhat arbitrary, an approximate model developed by Onsager, which yields an analytical solution, has been used to evaluate the location of the boundary of the vacuum core more correctly. The results show that the location of this ''top of the atmosphere,'' in density scale heights, changes with the peripheral speed of the centrifuge. Using this location in the calculation of separation performance parameters of the gas centrifuge reduces, at the higher peripheral speeds, the contribution of axial diffusion to the effective stage length of a theoretical stage in the centrifuge. The correction due to imposing the top of the atmosphere limitation on axial diffusion becomes significant at high speeds and low countercurrent circulation rates.},

doi = {},

journal = {Nucl. Technol.; (United States)},

number = ,

volume = 62:3,

place = {United States},

year = {1983},

month = {9}

}