1. NAME AND TITLE
PEPIN: Methodology for Computing Concentrations, Activities, Gamma-Ray Spectra, and
Residual Heat from Fission Products.
Independent Yields Library: 8 independent yields for 235U, 238U, 239Pu, 232Th, 233U.
Chain Library: Precursor chain file for 635 nuclides.
Gamma-Ray Energies Library: Average beta and gamma-ray energies in increasing order.
CEA Centre d'Etudes Nucleaires de Saclay, France.
3. CODING LANGUAGE AND COMPUTER
FORTRAN IV; IBM 360/370.
4. NATURE OF PROBLEM SOLVED
The concentrations, activities, gamma-ray spectra, and residual heat from fission products can
be calculated as a function of time for instantaneous fission or for one or more irradiation steps.
5. METHOD OF SOLUTION
Using the basic data in the libraries, the PEPIN code solves the differential equations satisfied
by the fission product concentrations.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
The sample problem ran in less than 30 seconds on the IBM 360/91 computer.
8. COMPUTER HARDWARE REQUIREMENTS
PEPIN was designed for an IBM 360 computer. It requires approximately 270 K storage.
9. COMPUTER SOFTWARE REQUIREMENTS
A FORTRAN IV compiler is required.
"Description of the Pepin Library," Informal notes.
"Pepin Input Data," Informal notes.
11. CONTENTS OF CODE PACKAGE
Included are the referenced documents and one (1.2MB) DOS diskette which contains the
source codes, data libraries, overlay cards, and input and output from the sample problem.
12. DATE OF ABSTRACT
KEYWORD: FISSION PRODUCT INVENTORY