**1. NAME AND TITLE**

DTF-TRACA: One-Dimensional Multigroup Neutron Transport Discrete Ordinates Code System.

DTF-TRACA is a modification of the CCC-42/DTF-IV code system.

**2. CONTRIBUTOR**

Junta de Energia Nuclear, Madrid, Spain, through the OECD NEA Data Bank, Gif-sur-Yvette, France.

**3. CODING LANGUAGE AND COMPUTER**

Fortran; UNIVAC 1100.

**4. NATURE OF PROBLEM SOLVED**

DTF-TRACA performs the original DTF-IV calculations of independent source, effective multiplication factor by fission, time absorption and criticality searches on material concentrations, zone widths, and total dimensions of the system. In addition, the new version performs two new eigenvalue calculations.

**5. METHOD OF SOLUTION**

DTF-IV solves, by the methods of discrete ordinates (Carlson SN), the multigroup, one-dimensional (plane, cylinder, sphere) Boltzmann transport equation. Anisotropic scattering is represented by Legendre polynomial expansion of the differential scattering cross-section. A complete energy-transfer scattering matrix is allowed for each Legendre component of scattering cross-section matrices.

Energy dependence is treated by the multigroup approximation and angular dependence by a general discrete ordinates approximation. Anisotropic scattering is approximated by a truncated spherical harmonics expansion of the scattering kernel. Within-group scattering and up-scattering (if any) iteration processes are accelerated by system-wide renormalization procedures.

DTF-TRACA does two eigenvalue calculations, the effective multiplication factor per collision and the criticality search on the buckling value. Also, it permits the input of density factors by interval and buckling by zone and group and calculates and writes on tape the sets of collapsed cross sections weighted with the calculated fluxes, in the structure of zones and groups asked by the user.

**6. RESTRICTIONS AND LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for DTF-TRACA.

**8. COMPUTER HARDWARE REQUIREMENTS**

DTF-TRACA is operable on the UNIVAC 1100 computer.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCE**

C. Ahnert, *The Neutron Transport Code DTF-TRACA User's Manual and Input
Data*, J.E.N.448 (1979).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and a reel of magnetic tape which contains the source code and printed output written in EBCDIC card images; total records 2704.

**12. DATE OF ABSTRACT**

February 1982; revised February 1983.

**KEYWORDS: ** NEUTRON; GAMMA-RAY; DISCRETE ORDINATES; ONE-
DIMENSION; MULTIGROUP; CROSS SECTION PROCESSING