NEA-1086 TRISTAN.

1. NAME OR DESIGNATION OF PROGRAM:  TRISTAN (Three-Dimensional Transport Analysis).
A multigroup three-dimensional discrete ordinates radiation transport code on the basis of the method of direct integration.

3. DESCRIPTION OF PROGRAM OR FUNCTION

The TRISTAN code solves three-dimensional Boltzmann transport equation for neutrons or gamma rays in rectangular geometry. The code can solve an adjoint problem as well as an usual transport problem. It can not be applied to the criticality problem because the source must be fixed. The TRISTAN is a suitable tool to analyze such radiation shielding problems as the streaming problems and the deep penetration problems.

4. METHODS

The solution technique is the method of direct integration which is a kind of the method of characteristics based on analytical integration along the radiation trajectories in several directions. This method, originated by K. Takeuchi, is suitable for the radiation shielding problems because of its exactness in the treatment of the streaming term of the transport equation.

The TRISTAN code was developed to solve the Boltzmann transport equation in the group theory in (x,y,z) coordinates. A numerical integration of double-differential cross section is applied to represent precisely the anisotropic scattering instead of using the Legendre polynomial expansion. TRISTAN includes several techniques such as a separation of the flux into the scattered and unscattered components and a conservation of radiation flux restored by a balance equation. The principal feature that enhance the applicability of TRISTAN is the utilization of a stratification of angular mesh and an adjoint solution to reduce the required computational time.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

TRISTAN does not use variable (flexible) dimensioning to facilitate efficient core data storage allocation yet. Therefore each user must reset each array size according to the spatial and angular mesh sizes he wants to use by changing the parameter statements in TRISTAN.

6. TYPICAL RUNNING TIME

The sample problem with 252 spatial meshes, 168 angular meshes and 5 neutron groups, included in the code package, required about 6 minutes by a HITAC M-280. Several hours of CPU time will be required for a practical shielding analysis, although the CPU time required depends on the problem size and the numerical option.

8. RELATED OR AUXILIARY PROGRAMS

AUXILIARY DATA LIBRARIES:
1- NDX42
42-group neutron cross section set for the nuclides listed in table 1. Its group structure is the same as GICX40 cross section set and is shown in table 2-(a)

2- NDX50
50-group neutron cross section set for the nuclides listed in table 1. Its group structure has 0.1 lethargy energy width and is shown in table 2-(b)

- T. Ida, S. Kondo, Y. Togo and Y. Oka:
  Development of Radiation Transport Code in Three-Dimensional
  (X,Y,Z) for Shielding Analysis by Direct Integration Method.
  Reprint from "Journal of Nuclear Science and Technology",
  24[3]  (March 1987), pp. 181-193.
- T. Ida, Y. Oka, S. Kondo and Y. Togo:
TRISTAN, A Three dimensional radiation transport calculation code by the direct
integration method
UTNL-R-204 (March 1987)

11. HARDWARE REQUIREMENTS

- HITAC M-200H, M-280
- It will be easy to make TRISTAN operable on an IBM machine
- Auxiliary storage requirement excluding the standard input and output devices
- No channel dependent
- A printer

13. SOFTWARE REQUIREMENTS

A system subroutine CLOCK is called to sample CPU time. This routine should be substituted for the appropriate system subroutine in the other systems.

15. NAME AND ESTABLISHMENT OF AUTHORS

Toshio Ida
Mitsubishi Atomic Power Industries, Inc.
Tokyo, Japan

Shuji Ohno, Makoto Yokozama, Yoshiaki Oka and Yasumasa Togo
Dept. of Nuclear Engineering
University of Tokyo
7-3-1, Hongo, Bunkyo-ku,
TOKYO 113-8656
Japan

Shunsuke Kondo
Nuclear Energy Research Laboratory
University of Tokyo
7-3-1, Hongo, Bunkyo-ku,
TOKYO 113-8656
Japan

CROSS SECTION DATA FILE
TRISTAN INPUT DATA
TRISTAN JCL
RES3 lNPUT DATA
RES6 INPUT DATA
TRISTAN SOURCE (PS)
SAMPLE INPUT OF JRR-4 GEOMETRY
JOB CONTROL FILE (HITAC VO63)
SAMPLE OUTPUT WRITTEN AS UNIT 3
SAMPLE OUTPUT WRITTEN AS UNIT 6
JW220_TRIISTAN.PDF Electronic documentation
JW220_TRIISTAN.TXT Content of files
NEA_1086_1_V2.PDF Electronic documentation