1. NAME AND TITLE

SPECTER-ANL: Neutron Damage Calculations for Materials Irradiations.

AUXILIARY ROUTINE:

SPECOMP: Neutron Damage Calculations for Compounds.

DATA LIBRARIES:

GAS157: ENDF/B-V gas production file.

MACKLIB: Kerma or Rads total damage library from ENDF/B-IV.

PKAMIN: Primary knock-on atom data.

SIGD: Displacements-per-atom data.

2. CONTRIBUTOR

Argonne National Laboratory, Argonne, Illinois.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; VAX.

4. NATURE OF PROBLEM SOLVED

SPECTER calculates spectral-averaged displacements, recoil spectra, gas production, and total damage energy (Kerma) for 41 pure elements using ENDF/B-V derived cross sections. The user need only specify a neutron energy spectrum. Because SPECTER does not handle compounds, SPECOMP was developed to determine displacement damage for alloys, insulators, and breeder materials.

5. METHOD OF SOLUTION

In SPECTER elastic scattering is treated exactly including angular distributions from ENDF/B-V. Inelastic scattering calculations consider both discrete and continuous nuclear level distributions. 24HMultiple (n,xn) reactions use a Monte Carlo technique to derive the recoil distributions. The (n,d) and (n,t) reactions are treated as (n,p) and (n,³He) as (n,⁴He). The neutron-gamma reaction and subsequent beta-decay are also included, using a new treatment of gamma-gamma coincidences, angular correlations, beta-neutrino correlations and the incident neutron energy. The Lindhard model was used to compute the energy available for nuclear displacement at each recoil energy. SPECOMP reads the required files from SPECTER, computes secondary displacement functions for each combination of recoil and matrix atom, and then integrates over recoil energy to find the net displacement cross section at each neutron energy. Damage due to neutron, gamma-ray and beta decay events is then added in and the results are summed to obtain the total dpa cross section.

6. RESTRICTIONS OR LIMITATIONS

The DISCS computer code was used to process ENDF/B-V data for 41 pure elements for use with SPECTER-ANL. SPECOMP can use any combination of four elements in a single run.

7. TYPICAL RUNNING TIME

SPECTER used about 13 minutes of wall clock time on the VAX 8650 under VAX/VMS 4.5 operating system using the sample data provided. SPECOMP took about 2 minutes of wall clock time to execute.

8. COMPUTER HARDWARE REQUIREMENTS

SPECTER-ANL and SPECOMP run on the VAX. Versions have also run on Cray and IBM computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The VAX Fortran 4.6 compiler was used.

10. REFERENCES

L. R. Greenwood and R. K. Smither, "SPECTER: Neutron Damage Calculations For Materials Irradiations," ANL/FPP/TM-197 (January 1985).

L. R. Greenwood, "Compound Displacement Damage Calculations with SPECOMP," Informal Notes, Argonne National Laboratory, (February 1988).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source codes plus sample problem input and output.

12. DATE OF ABSTRACT

April 1988.