CCC-0293 TRIDENT.

1. NAME OR DESIGNATION OF PROGRAM:  TRIDENT.
Two-Dimensional Multigroup Discrete Ordinates Transport Code for (X,Y) and (R,Z) Geometries.

3. DESCRIPTION OF PROBLEM OR FUNCTION

TRIDENT solves the two- dimensional-multigroup-transport equations in rectangular (x-y) and  cylindrical (r-z) geometries using a regular triangular mesh.
Regular and adjoint, inhomogeneous and homogeneous (K-eff and eigenvalue searches) problems subject to vacuum, reflective, white,  or source boundary conditions are solved. General anisotropic scattering is allowed and anisotropic-distributed sources are permitted.

4. METHOD OF SOLUTION

The discrete-ordinates approximation is used for the neutron directional variables. An option is included to append a fictitious source to the discrete-ordinates equations that  is defined such that spherical-harmonics solutions (in x-y geometry) or spherical-harmonics-like solutions (in r-z geometry) are obtained. This option is useful for cases in which ray-effect distortions are severe. A spatial-finite-element method is used in which the angular flux is expressed as a linear polynomial in each triangle that is discontinuous at triangle boundaries. Both inner (within-group) and outer iteration cycles are accelerated by either  whole-system or fine-mesh rebalance.
Provision is made for creation of standard interface output files for Sn constants, angle-integrated (scalar) fluxes, and angular fluxes. Standard interface input files for Sn constants, inhomogeneous sources, cross sections, and the scalar flux may be read. Subroutines DRED and DRIT perform information transfers between LCM and random disk. Data transfer between large and small core are performed by CRED and CRIT. Sequential binary operations are performed by SEEK, REED, and RITE. Flexible edit options as well as a dump and restart capability are provided.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Variable
dimensioning is used so that any combination of problem parameters leading to a container array less than MAXLEN can be accommodated. On CDC Machines MAXLEN can be about 40 000 words of Small Core Memory (SCM) and Large Core Memory (LCM) is used for most group- dependent data. On IBM machines, TRIDENT executes in double precision (8 bytes per Word) so that MAXLEN can be on the order of 100 000 or more. Although most problems can be fast core contained on the IBM machine and SCM and LCM contained on the CDC machine, an  option exists to automatically overflow the storage of selected large arrays to random disk if necessary.

6. TYPICAL RUNNING TIME

A six group, S2, 1700 triangle, K-eff calculation of an EBR-II core modeled in x-y geometry requires approximately 4.4 min of CDC-7600 time. This is approximately the same as the TRIPLET running time. Running times vary almost linearly with the total number of unknowns. When the ray-effect correction option is used, the running time is increased by a factor of approximately two, depending upon the problem.

NEA-DB executed the test case included in the package on CDC 7600 in 192 seconds of CPU time.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- R. Douglas O'Dell and Raymond E. Alcouffe:
  Transport Calculations for Nuclear Analyses: Theory and
  Guidelines for Effective Use of Transport Codes
  LA-10983-MS and UC-32 (September 1987)

- T.J. Seed, W.F. Miller, F.W. Brinkley:
"TRIDENT; A Two-Dimensional, Multigroup, Triangular Mesh
Discrete Ordinates, Explicit Neutron Transport Code"
LA-6735-M, (March 1977)
- Daniel Carson:
"Core to Core Conversion by Daniel Carson"
ANL-K250S-1 (Revision, February 1970)
- T.J. Seed, W.F. Miller, F.W. Brinkley:
"TRIDENT; A Two-Dimensional, Multigroup, Triangular Mesh
Discrete Ordinates, Explicit Neutron Transport Code"
LA-6735-M, (March 1977)
- Daniel Carson:
"Core to Core Conversion by Daniel Carson"
ANL-K250S-1 (Revision, February 1970)

11. MACHINE REQUIREMENTS

A maximum of three interface units, open at once, and three system input/output units are required. One random-  disk unit is required if the automatic-data-overflow option is used. A large bulk memory is assumed by the code such as the CDC-7600 LCM. This function may, however, be replaced by a portion of fast-core memory with IBM 360 machines or by disk, drum, or tape storage.

To run the test case on CDC 7600, main storage require- ments are: 62000 octal words of SCM; 241000 octal words of LCM.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:

7000 SCOPE 2.1 LVL 533-A0.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by: Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.
Developed by:   Los Alamos National Laboratory, Los Alamos, New Mexico, USA

File name	File description	Records
CCC0293_01.003	TRIDENT INFORMATION FILE	49
CCC0293_01.004	TRIDENT SOURCE PROGRAM (FORTRAN-4)	11561
CCC0293_01.005	SYSTEM SUBROUTINES (FORTRAN-4)	315
CCC0293_01.006	ECRDWR SUBROUTINE	12
CCC0293_01.007	TRIDENT TEST CASE INPUT DATA	571
CCC0293_01.008	TRIDENT JCL	20
CCC0293_01.009	TRIDENT TEST CASE PRINTED OUTPUT	13815

File name	File description	Records
CCC0293_02.001	SOURCE PROGRAM (F4,EBCDIC)	11972
CCC0293_02.002	SOURCE PROGRAM (ASSEMBLER,EBCDIC)	694
CCC0293_02.003	DD CARDS FOR THE EXECUTION	28
CCC0293_02.004	OVERLAY CARDS	30
CCC0293_02.005	SAMPLE PROBLEM INPUT DATA	571
CCC0293_02.006	SAMPLE PROBLEM PRINTED OUTPUT	17445