1. NAME AND TITLE

POLLA: A Fortran Program to convert R-MATRIX-Type Multilevel Resonance Parameters for Fissile Nuclei into Equivalent KAPUR-PEIERLS-Type Parameters.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 3033.

4. NATURE OF PROBLEM SOLVED

POLLA converts a set of R-matrix resonance parameters for fissile nuclei into an equivalent set of Kapur-Pierls parameters. The program utilizes the multilevel formalism developed by Reich and Moore and avoids the diagonalization of the level matrix, hence it is particularly useful where many levels and few fission channels are involved.

5. METHOD OF SOLUTION

The program is designed to convert R-matrix parameters into equivalent Kapur-Peierls parameters. The program obtains the Kapur-Peierls parameters by the direct partial fraction expansion of the Reich and Moore expression of the collision matrix. This direct approach appears simpler and faster when the number of fission channels is known and small. (The program is coded for a maximum of four fission channels.) The method, like the Reich and Moore formalism, is particularly useful when a large number of levels must be considered because it does not require the diagonalization of a large level matrix.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

To compile and execute the sample problem using the OS/VS2 operating system on the IBM 3033 computer required 22 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

Input/Output units are required. The storage requirement is 366 K and 200 K for execution of the sample problems.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCE

G. de Saussure, R. B. Perez, "POLLA, A Fortran Program to Convert R-MATRIX-TYPE," ORNL-TM-2599 (June 1969).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and sample problems and output.

12. DATE OF ABSTRACT

October 1984.