NEA-0387 TIMOC-72.

1. NAME OR DESIGNATION OF PROGRAM:  TIMOC-72.

3. NATURE OF PHYSICAL PROBLEM SOLVED

TIMOC solves the energy and time  dependent (or stationary) homogeneous or inhomogeneous neutron transport equation in three-dimensional geometries. The program can  treat all commonly used scattering kernels, such as absorption, fission, isotropic and anisotropic elastic scattering, level excitation, the evaporation model, and the energy transfer matrix model, which includes (n,2n) reactions. The exchangeable geometry routines consist at present of (a) periodical multilayer slab, spherical and cylindrical lattices, (b) an elaborate three-dimensional cylindrical geometry which allows all kinds of subdivisions, (c) the very flexible O5R geometry routine which is able to describe any body combinations with surfaces of second order. The program samples the stationary or time-energy-region dependent fluxes as well as the transmission ratios between geometrical regions and the following integral quantities or eigenvalues, the leakage rate, the slowing down density, the production to source ratio, the multiplication factor based on flux  and collision estimator, the mean production time, the mean destruction time, time distribution of production and destruction, the fission rates, the energy dependent absorption rates, the energy deposition due to elastic scattering for the different geometrical regions.

4. METHOD OF SOLUTION

TIMOC is a Monte Carlo program and uses several, partially optional variance reducing techniques, such as the method  of expected values (weight factor), Russian roulette, the method of  fractional generated neutrons, double sampling, semi-systematic sampling and the method of expected leakage probability. Within the  neutron lifetime a discrete energy value is given after each collision process. The nuclear data input is however done by group averaged cross sections. The program can generate the neutron fluxes either resulting from an external source or in the form of fundamental mode distributions by a special source iteration procedure. In this latter case, the sampling of eigenvalues is based on the life cycle.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Number of energy groups - 50
number of isotopes - 20
number of isotope mixtures - 20

7. UNUSUAL FEATURES OF THE PROGRAM

A special option allows the calculation of geometrical perturbation effects. In such calculations, the differential effect does not depend on the total variance of the considered quantity. The sampling of these differential effects is based on the method of similar flight paths.

8. RELATED AND AUXILIARY PROGRAMS

The program can be linked to the ENDF/B data file via the CODAC-2 program. CODAC-2 generates for any desired group structure the nuclear parameters and group averaged cross sections needed by TIMOC.

- R. Jaarsma and H. Rief:
  TIMOC 72 Code Manual
  EUR 5016 e (1973)
- Modification of TIMOC 72
- H. Kschwendt and H. Rief:
  TIMOC - A General Purpose Monte Carlo Code for Stationary and Time
  Neutron Transport
  EUR 4519 e (1970)
- R.J. Jaarsma and H. Kschwendt:
  Geometry Routines for Use in the TIMOC Code
- Note from INGENIEROS on TIMOC-72/J2
  UNIVAC Implementation (30 May 1978)
- F.Beonio-Brocchieri and C.Daolio
CODAC 2 : A New Version of the CODAC Code Which Accepts
ENDF/B Version II Data for the Production of a Few Group Library
for TIMOC.
EUR/C-IS/816 72.e (March 1972)
- H.Krainer
CODAC, A FORTRAN IV Program to Process a TIMOC Library
From the ENDF/B File.
EUR-4512.e (1970)
- R. Jaarsma and H. Rief:
  TIMOC 72 Code Manual
  EUR 5016 e (1973)
- Modification of TIMOC 72
- H. Kschwendt and H. Rief:
  TIMOC - A General Purpose Monte Carlo Code for Stationary and Time
  Neutron Transport
  EUR 4519 e (1970)
- R.J. Jaarsma and H. Kschwendt:
  Geometry Routines for Use in the TIMOC Code

11. HARDWARE REQUIREMENTS: MACHINE REQUIREMENTS

13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED:  IBM370 O.S.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

15. NAME AND ESTABLISHMENT OF AUTHOR

R. Jaarsma and H. Rief
J.R.C. EURATOM
Ispra Establishment, Italy.

File name	File description	Records
NEA0387_01.001	SOURCE PROGRAM (F4)	4586
NEA0387_01.002	ASSEMBLER ROUTINE	49
NEA0387_01.003	SAMPLE PROBLEM DATA	203
NEA0387_01.004	SAMPLE PROBLEM PRINTED OUTPUT	315

File name	File description	Records
NEA0387_02.001	INFORMATION	3
NEA0387_02.002	FORTRAN SOURCE PROGRAMMES (MAIN -PACKAGE)	33
NEA0387_02.003	FORTRAN SOURCE PROGRAMMES (NDP -PACKAGE)	885
NEA0387_02.004	FORTRAN SOURCE PROGRAMMES (RWS -PACKAGE)	2130
NEA0387_02.005	FORTRAN SOURCE PROGRAMMES (GEOM -PACKAGE)	1417
NEA0387_02.006	ASSEMBLER PROGRAMMES (LOC -PACKAGE)	8
NEA0387_02.007	ASSEMBLER PROGRAMMES (RANDOM-PACKAGE)	549
NEA0387_02.008	INPUT DATA FOR SAMPLE PROBLEM NO.1	203
NEA0387_02.009	PRINTED OUTPUT OF SAMPLE PROBLEM NO.1	339
NEA0387_02.010	INPUT DATA FOR SAMPLE PROBLEM NO.2	184
NEA0387_02.011	PRINTED OUTPUT OF SAMPLE PROBLEM NO.2	720
NEA0387_02.012	FORTRAN SOURCE PROGRAMME OF PLOTGEOM	1054
NEA0387_02.013	SAMPLE PROBLEM FOR PLOTGEOM	79
NEA0387_02.014	SAMPLE OUTPUT OF PLOTGEOM	193
NEA0387_02.015	SPECIAL VERSIONS OF SUB. STRDIR AND NDFIS	375