NEA-0933 MULTI-KENO.

1. NAME OR DESIGNATION OF PROGRAM:  MULTI-KENO.

3. DESCRIPTION OF PROBLEM OR FUNCTION

MULTI-KENO has been developed from the criticality safety analysis code KENO-4. KENO-4 was extended so that a system is divided into many subsystem superboxes, where the size of box types in each superbox can be selected independently.

4. METHOD OF SOLUTION

MULTI-KENO solves the Boltzmann neutron transport equation under the assumptions that the media are isotropic and the cross sections are independent of time.
The scattering treatment used in MULTI-KENO assumes that the differential neutron scattering cross section can be represented by  a P1 Legendre polynomial. No neutron absorption is allowed in MULTI-KENO. Instead, at each collision point of a neutron tracking history the weight of the neutron is reduced by the absorption probability. When the neutron weight has been reduced below a specified value for the region in which the collision occurs, Russian roulette is played to determine whether the neutron history  has to be terminated or whether the neutron should survive with an increased weight. Splitting of high-weight neutrons is allowed in order to minimize the variance in keff for systems with regions of widely varying average weight.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

MULTI-KENO is flexibly dimensioned so that the allowed size of a problem is limited only by the total data storage available.

6. TYPICAL RUNNING TIME

Running times are highly problem dependent. Typical problems run between 2 and 50 minutes on a FACOM-M200 depending on the number of histories requested, the statistical weighting used, the presence or absence of reflectors, the complexity of the geometry, the number of energy groups and the type of materials in the problem. An infinite cylinder of highly enriched 235U-H2O was executed on a FACOM-M380 in 11.08 minutes; neutron histories were 30,000, and the number of energy groups was 137.

This version contains corrections to NEA 0933/02. No attempt was made by NEA-DB to implement the package again. The following information therefore pertains to the previous version /02, which had been implemented by NEA-DB but is now superseded by the present version: NEA-DB ran the two test cases included in this  package on an IBM 3090 computer. Dual central processing systems SY1 and SY2 were used. The computation speed of SY2 is nearly twice that of SY1. When comparing the following CPU times, this fact has to be  taken into account:
test case 1 (SY1): 22 min 19 seconds
test case 2 (SY2): 13 min 16 seconds.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

MAIL - A code to process effective macroscopic cross sections.

10. REFERENCES

- L.M. Peirie, N.F. Cross:
  KENO IV: An Improved Monte Carlo Criticality Program
  ORNL-4938 (November 1975)

- Y. Naito, M. Yokota and K. Nakano:
  MULTI-KENO: A Monte Carlo Code for Criticality Safety Analysis.
  JAERI-M 83-049  (March 1983)
- Y. Komuro:
  MULTI-KENO-2: A Modified Version of MULTI-KENO.
  Supplement to Report JAERI-M 83-049 (Draft, July 1985)

11. MACHINE REQUIREMENTS

(A) CALCOMP Plotter.
(B) Output file for graphics processing.
NEA 0933/03: This version contains corrections to NEA 0933/02. No attempt was made by NEA-DB to implement the package again. The following information therefore pertains to the previous version /02, which had been implemented by NEA-DB but is now superseded by the present version: To run the test cases included in this package  on an IBM 3090 computer, 3228K bytes of main storage are required.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  MVS-SP (IBM3081).

This version contains corrections to NEA 0933/02. No attempt was made by NEA-DB to implement the package again. The following information therefore pertains to the previous version /02, which had been implemented by NEA-DB but is now superseded by the present version: MVS (IBM 3090).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by:
                Japan Atomic Energy Research Institute
                Tokai Research Establishment
                Tokai-mura, Naka-gun, Ibaraki-ken
                Japan

File name	File description	Records
NEA0933_03.001	MULTI-KENO-2 Information file	416
NEA0933_03.002	MULTI-KENO-2 Source Code (FORTRAN-H-EXT)	14370
NEA0933_03.003	MULTI-KENO-2 Source Code (for IEBUPDTE)	14483
NEA0933_03.004	SETB99 Source Code (ASSEMBLER)	100
NEA0933_03.005	Bit Manipulation source code (FORTRAN)	107
NEA0933_03.006	MULTI-KENO-2 Overlay Cards	48
NEA0933_03.007	MULTI-KENO-2 Job Control File	131
NEA0933_03.008	MULTI-KENO-2 Test Case 1 Input File	129
NEA0933_03.009	MULTI-KENO-2 Test Case 2 Input File	157
NEA0933_03.010	MULTI-KENO-2 Library Data for test case 1	65886
NEA0933_03.011	MULTI-KENO-2 Library Data for test case 2	8263
NEA0933_03.012	MULTI-KENO-2 Printed Output for test case 1	11232
NEA0933_03.013	MULTI-KENO-2 Printed Output for test case 2	2949
NEA0933_03.014	Data Libraries Processing (JCL and source)	310