NESC0184 BRT1

1. NAME OR DESIGNATION OF PROGRAM:  BRT1

3. DESCRIPTION OF PROBLEM OR FUNCTION

BRT1, like the original THERMOS code developed by H. Honeck of Brookhaven National Laboratory, computes the scalar thermal neutron spectrum as a function of position in a lattice by solving the integral transport equation with isotropic scattering. One-dimensional slab or cylindrical geometry may be used. As output the code supplies flux-averaged values of sigma a, sigma f, nu sigma f, sigma s, and d for the cell  composition and the values of sigma a, sigma f, nu sigma f, sigma s, and sigma tr for the isotopic constituents.

4. METHOD OF SOLUTION

The method used in solving the transport integral equation is the power iteration method. To accelerate convergence the code uses a combination of Gauss iteration, renormalization, over-relaxation, and extrapolation procedures.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   30 speed groups
   30 space points
   30 isotopes in mixture
   30 isotopes in the edit
    8 mixtures

6. TYPICAL RUNNING TIME

The sample problem is a 2-region slab and is  solved using 10 space points and 30 speed groups. There are two mixtures used. Five materials are used in the cell and one in the edit. The time in general is a function of the number of space points and energy groups used by the problem.
Typical running time for BRT1 with the random access library is one minute with a reflecting boundary condition and 30 seconds with a white boundary condition. Succeeding cases require approximately 15 seconds each.

7. UNUSUAL FEATURES OF THE PROGRAM

In BRT1 options include the white  boundary condition, current calculation, transverse buckling, linear anisotropic scattering correction, and smeared cell punched output for use as region input to a succeeding case. Random access library  data can be stored on drum or disk.

8. RELATED AND AUXILIARY PROGRAMS

RLITHE updates and/or prints the BRT data tape or random access data.

10. REFERENCES

- H.C. Honeck:
  A Thermalization Transport Theory Code for Reactor Lattice
  Calculations
  BNL-5826 (September 1961).
- H.C. Honeck:
  The Distribution of Thermal Neutrons in Space and Energy in
  Reactor Lattices Part 1 - Theory
  Nuclear Science and Engineering, p. 193 (1960).
- D.R. Skeen and L.J. Page:
  THERMOS/Battelle..The Battelle Version of the THERMOS Code
  BNWL-516 (June 1967).

- C.L. Bennett and W.L. Purcell:
  BRT-I Battelle Revised THERMOS
  BNWL-1434 (June 1970).
- THERMOS: A Thermalization Transport Theory Code for Reactor
Lattice Calculations (BNL-5826
- B.J. Toppel and I. Baksys:
The Argonne-Revised THERMOS Code
ANL-7023 (March 1965)
- O. Fetzmann:
Beschreibung der Aenderungen in den Programmen
THERMOS, GAKER und LIBP (TM-PH-377) 26/1/1971

11. MACHINE REQUIREMENTS

64K memory, input, output, program, library,  and punch units plus 3 scratch units or equivalent drum storage.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   CSCX.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

                 C. L. Bennett and W. L. Purcell
                 Reactor Physics Department
                 Pacific Northwest Laboratories
                 Battelle
                 P. O. Box 999
                 Richland, Washington  99352

source program   mag tape                                           SRCTP
test-case data   mag tape                                           DATTP
test-case output mag tape                                           OUTTP
aux program      mag tape                                           AUXTP
report                                                              REPPT
user's guide                                                        WRKPT

File name	File description	Records
NESC0184_01.001	RLITHE SOURCE PROGRAMME	494
NESC0184_01.002	RLITHE LIBRARY INPUT DATA	7450
NESC0184_01.003	BRT-1 SOURCE PROGRAMME	2571
NESC0184_01.004	BRT-1 JCL+OVERLAY CARDS+SAMPLE INPUT	39
NESC0184_01.005	RLITHE PRINT OUT OF THE LIBRARY	4968
NESC0184_01.006	BRT-1 SAMPLE OUTPUT	547