1. NAME AND TITLE

SANDOR: Isotope Generation and Depletion Code Matrix Exponential Method.

This code was developed specifically for Control Data Corporation computers from the original Oak Ridge National Laboratory ORIGEN code.

2. CONTRIBUTOR

Sandia Laboratories, Albuquerque, New Mexico.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC-7600 (C00364C760001).

4. NATURE OF PROBLEM SOLVED

SANDOR is a point code (no spatial dependence) which calculates detailed isotopic compositions for a wide range of problems involving nuclear reactor fuel irradiation, neutron activation, and radioactive decay.

5. METHOD OF SOLUTION

The code solves the inhomogeneous system of coupled nonlinear, first-order differential equations which describe the allowable transitions between the various isotopes. Fission, neutron activation, and radioactive decay reactions are considered.

The solution technique consists of a linearization of the system of equations over discrete time steps and an update of appropriate coefficients between time steps. The coefficients of these equations are designated in this report as the transition matrix. Problems of extreme ratios of radioactive decay rates (which produce stiff differential equations) are dealt with by suitable approximations.

A nuclear data file listing 1,063 isotopes (254 structural materials, 101 actinides, and 708 fission products) contains the nuclear parameters, neutron cross sections and gamma-ray photon production data for four reactor types: high-temperature, gas-cooled reactor (HTGR), light water reactor (LWR), liquid-metal, fast-breeder reactor (LMFBR), and molten-salt breeder reactor (MSBR).

6. RESTRICTIONS OR LIMITATIONS

To conserve central memory space, the various subroutines used by the main program, ORIGEN, are arranged into five overlays. The use of the overlay loader requires that the initial routine in each overlay be a program and not a subroutine. This requirement means that data communication between different overlays must be through common blocks or mass storage.

The zero-level overlay is always resident in the computer. Each of the five first-level overlays is loaded as called by the resident program. This process completely overwrites the previously loaded overlay. Any information to be saved by an overlay must be incorporated permanently into the overlay, be in a common block, or be resident on the mass storage device. No second-level overlays are used.

7. TYPICAL RUNNING TIME

SANDOR can usually be executed in 30 seconds to 1 minute on the CDC 7600.

8. COMPUTER HARDWARE REQUIREMENTS

SANDOR is operable on the CDC 7600 computer. It uses 19 separate records on the mass storage device, with a total of about 56,200 words. The use of overlays saves about 3,350 words of central memory storage.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required under the SCOPE operating system.

10. REFERENCES

a) Included in documentation:

RSICC, "Readme.txt" (August 2000).

D. E. Bennett, "Revisions for NUREG/CR-0987" (1980).

D. E. Bennett, "SANDIA-ORIGEN User's Manual," NUREG/CR-0987, SAND 79-0299 (October 1979).

b) Background reference:

M. J. Bell, "ORIGENThe ORNL Isotope Generation and Depletion Code," ORNL-4628 (May 1973).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents in (10.a) with output from the sample problem written on microfiche, plus one DS/HD DOS diskette which contains the source codes, nuclear data library and sample problem input.

12. DATE OF ABSTRACT

February 1982, revised August 2000.

KEYWORDS: ISOTOPE INVENTORY; FISSION PRODUCT INVENTORY; MULTIGROUP; NEUTRON; GAMMA-RAY SOURCE; ACTINIDES