Computer Programs

NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROGRAM OR FUNCTION, METHODS, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, CPU, FEATURES, AUXILIARIES, STATUS, REFERENCES, REQUIREMENTS, LANGUAGE, SOFTWARE REQUIREMENTS, OTHER RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
---|---|---|---|

GRTUNCL-3D/R-THETA-Z | NEA-1690/01 | Arrived | 18-MAY-2005 |

Machines used:

Package ID | Orig. computer | Test computer |
---|---|---|

NEA-1690/01 | HP W.S.,SUN W.S. |

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3. DESCRIPTION OF PROGRAM OR FUNCTION

The existing two-dimensional GRTUNCL code was converted to compute the uncollided fluence at each spatial in an R-theta-Z grid and to generate the associated distributed first-collision source moments for use as a distributed source in the TORT three-dimensional discrete ordinates computed code. Because there is very little information on the GRTUNCL code, reviews of the essential elements underlying the methods were made and the changes performed to convert the exiting code into R-theta-Z version compatible with the TORT distributed source input option.

The existing two-dimensional GRTUNCL code was converted to compute the uncollided fluence at each spatial in an R-theta-Z grid and to generate the associated distributed first-collision source moments for use as a distributed source in the TORT three-dimensional discrete ordinates computed code. Because there is very little information on the GRTUNCL code, reviews of the essential elements underlying the methods were made and the changes performed to convert the exiting code into R-theta-Z version compatible with the TORT distributed source input option.

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4. METHODS

The representation of the scattering source in discrete ordinates methods stems from the representation of the collisional transfer differential cross section in terms of Legendre expansions. The scattering transfer integral of the equation can be further simplified by using the Legendre Additional Theorem. So the scattering transfer source for a transport problem can be and generally is mathematically represented. This type of representation of the scattering transfer term is standard in most deterministic transport codes although it is generally used in multigroup form with a truncated spherical harmonics expansion of a specified degree. A source in TORT at a spatial mesh in a discrete direction is presented by an expansion of spherical harmonic type with the source moments which the GRTUNCL 3D code needs to calculate. The values of the source moments for the first-collision source are the quantities produced by the extension of GRTUNCL code to 3D for input into TORT. Since the code works only for a point source, the uncollided flux in each spatial mesh is a delta function in direction. As a result, the moments of the flux expansion can be obtained by multiplying the uncollided fluence by the coefficients for the spherical harmonic expansion described above. The first collision source moments are then computed group by group using the group-to-group transfer Legendre expansion coefficients taken from an appropriate multigroup cross section set. This quantity is the desired quantity from running the GRTUNCL code.

The representation of the scattering source in discrete ordinates methods stems from the representation of the collisional transfer differential cross section in terms of Legendre expansions. The scattering transfer integral of the equation can be further simplified by using the Legendre Additional Theorem. So the scattering transfer source for a transport problem can be and generally is mathematically represented. This type of representation of the scattering transfer term is standard in most deterministic transport codes although it is generally used in multigroup form with a truncated spherical harmonics expansion of a specified degree. A source in TORT at a spatial mesh in a discrete direction is presented by an expansion of spherical harmonic type with the source moments which the GRTUNCL 3D code needs to calculate. The values of the source moments for the first-collision source are the quantities produced by the extension of GRTUNCL code to 3D for input into TORT. Since the code works only for a point source, the uncollided flux in each spatial mesh is a delta function in direction. As a result, the moments of the flux expansion can be obtained by multiplying the uncollided fluence by the coefficients for the spherical harmonic expansion described above. The first collision source moments are then computed group by group using the group-to-group transfer Legendre expansion coefficients taken from an appropriate multigroup cross section set. This quantity is the desired quantity from running the GRTUNCL code.

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NEA-1690/01, included references:

- F. Masukawa, et al.:GRTUNCL 3D: An Extension of the GRTUNCL Code to Compute R-Theta-Z First

Collision Source Moments

INS/S99-05(M) Institute of Nuclear Safety Code Manual (March 2000)

- F. MASUKAWA, et al.:

GRTUNCL-3D: An Extension of the GRTUNCL Code to Compute R-Theta-Z First

Collision Source Moments

Proc. of ICRS9, J. of NUCL. SCI. & TECHNOL. Suppl. 1, p.471-474 (March 2000)

- Appendix A Section 3.0 of the MASH 1.0 User's Manual

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NEA-1690/01

documentation in PDF

CAFDATS.pdf

GRTUNCL3D_appendix.pdf

GRTUNCL3D_doc.pdf

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- G. Radiological Safety, Hazard and Accident Analysis
- J. Gamma Heating and Shield Design

Keywords: cylindrical geometry, discrete ordinate method, first collision, gamma ray, multigroup, neutron, three-dimensional, two-dimensional.