1. NAME AND TITLE

ISO-PC 2.1: Kernel Integration Code System for General Purpose Isotope Shielding Analyses.

DATA LIBRARIES

Photon & electron production data

Mass attenuation coefficients

Buildup factors

2. CONTRIBUTOR

Flour Daniel Northwest (formerly Westinghouse Hanford Company), Richland, Washington.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC (C00636/IBMPC/01).

4. NATURE OF PROBLEM SOLVED

ISO-PC is a revision to the CCC-079/ ISOSHLD-II program. It calculates dose rates from the decay of radionuclides at the exterior of simple geometric shapes. The dose rates from X-rays, gamma-rays and bremsstrahlung radiation are computed. The portion of the program which computes fission product inventories (RIBD) has been removed. The ISO-PC program is strictly a shielding code for simple arrangements of source and shields.

Version 2.1, which replaced Version 1.98 in November 1996, contains several changes and improvements:

1) three new geometries were added for hollow cylinders

2) maximum number of shield regions increased from 5 to 6

3) the DELR parameter is now computed internally.

4) several nuclides were added to the library

5) the definition of ICONC was expanded to include mass concentrations

6) new NAMELIST variables were added to allow input in SI units with standard prefix multipliers.

SOURCE AND SHIELD GEOMETRIES

1. Point source with slab shields

2. Line source with slab shields

3. Sphere with spherical or slab shields

4. Truncated cone with slab shields

5. Infinite slab or infinite plane with infinite slab shields

6. Flat disc with slab shields

7. Cylinder with cylindrical or slab shields or a combination of one cylindrical shield with two slab shields and the region between

8. End of a cylinder with slab shields

9. Rectangular solid with slab shields

10. Cylindrical shell sources with cylindrical and slab shields

SHIELD MATERIALS

1. At most 6 shield regions, including the source

2. At most 45 shield materials may be specified for each region

3. User must specify which region to use for buildup factors

SOURCE REGION

1. Specify source strength as the total in the source region or a uniform concentration

2. Specify source strength using library of 535 nuclides or give photons/sec at specific energies

MISCELLANEOUS FEATURES

1. 30 energy groups for photons from 10 keV to 10 MeV

2. Final dose rate as exposure rate or dose equivalent rate

3. Use up to 40 dose points (different distances from source) in a single case

4. Each run may have multiple cases

5. Use SI or traditional units for activity or dose rate.

5. METHOD OF SOLUTION

The photon spectrum for the source region is computed for a fixed energy mesh from the library of photon data. Bremsstrahlung is computed from the library of electron data using tables of bremsstrahlung emission at selected atomic numbers and energies.

The point source attenuation "kernel" (buildup factor times attenuation factor times geometry factor) is integrated over the source region for as many as 30 energy groups. Low energy (less than 100 keV) buildup factors are computed from a table of values stored in the data library. Higher energy buildup is computed from Taylor coefficients.

6. RESTRICTIONS OR LIMITATIONS

The bremsstrahlung calculation does not distinguish between internal conversion electrons, beta decay, or positron emission. All the electron data is treated as (allowed) beta decay.

The attenuation and buildup calculation does not use the recent data found in ANSI/ANS-6.4.3-1991. The differences are small for all materials except water. For water, the newer data predicts much smaller buildup.

7. TYPICAL RUNNING TIME

The first test case which is run during the automated installation computes dose rates for several cases. There is a total of about 15,000 integration points. This run requires 21 seconds on a 486/33 CPU.

8. COMPUTER HARDWARE REQUIREMENTS

The standard executable requires at least an 80386 CPU with the 80387 numeric data processor and 200 kbytes free RAM. The entire collection of files distributed with the program requires less than 5 Mbyte of disk storage space. Input and output files created by the user will require additional disk space.

9. COMPUTER SOFTWARE REQUIREMENTS

Both ISO-PC 2.1 and ISO-PC 1.98 are included in this distribution. The Lahey F77 version 5.01 compiler was used to create the ISO-PC executables included in the package. ISO-PC requires DOS version 3 or higher. Version 2.1 runs in a DOS window of Win95. For version 1.98 the ANSI.SYS driver is optional for running ISO-PC, since it only affects the appearance of the screen output. However, without this driver, the odd looking characters that control colors and clear the screen will be visible at the beginning of some lines.

10. REFERENCES

P. D. Rittmann, "Notes for Users of ISO-PC Version 2.1" (February 1996).

P. D. Rittmann, "Summary of Changes to ISO-PC Version 2.1" (1996).

P. D. Rittmann, "ISO-PC Version 2.1 Summary" (1996).

P. D. Rittmann, "ISO-PC Version 1.98 - User's Guide," WHC-SD-WM-UM-030 Rev. 0 (1995).

G. L. Simmons, J. J. Regimbal, J. Greenborg, E. L. Kelly, Jr., and H. H. Van Tuyl, "ISOSHLD-II: Code Revision to Include Calculation of Dose Rate from Shielded Bremsstrahlung Sources," BNWL-236-SUP1 (1967) .

R. L. Engle, J. Greenborg, and N. M. Hendrickson, "ISOSHLD - A Computer Code for General Purpose Isotope Shielding Analysis," BNWL-236 (1966).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and a DOS diskette containing a self-extracting compressed DOS file which contains the executables, user's guide, batch files, source code, and sample input and output files.

12. DATE OF ABSTRACT

July 1995, revised November 1996.