NEA-1339 PEPIN.

1. NAME OR DESIGNATION OF PROGRAM:  PEPIN : Methodology for Computing Concentrations, Activities, Gamma-Ray Spectra, and Residual heat from Fission Products.

3. DESCRIPTION OF PROGRAM OR FUNCTION

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.

4. METHODS

Using the basic data in the libraries, the PEPIN code solves the differential equations satisfied by the fission product concentrations.
Data Libraries :
Independent Yields Library: 8 independent yields for 235U, 238U,
239U, 232U, 233U.
Chain library: Precursor chain file for 635 nuclides.
Gamma-Ray Energies Library: Average beta and gamma-ray energies in increasing order.

The number of nuclides must not exceed 650.
The number of Gamma-Rays must not exceed 8500.
The number of decay times must not exceed 59.
The number of irradiation steps must not exceed 40.

A few seconds on an Intel Pentium II 450MHz.

- B. Duchemin and C. Nordborg:
  Decay Heat Calculation - An International Nuclear Code Comparison
  NEACRP-319 "L", NEANDC-275 "U" (April 1990).
- "Description of the Pepin Library" Informal notes.
- "Pepin Input Data" Informal notes.

15. NAME AND ESTABLISHMENT OF AUTHORS: , CEA,, Saclay, France

PEPIN.EXE compressed file containing the list below:
F01 INDEPENDENT YIELDS LIBRARY
F02 CHAIN LIBRARY
F03 GAMMA-RAY ENERGIES LIBRARY
F04 PEPIN JCL
F05 PEPIN FORTRAN IV SOURCE
F06 PEPIN OVERLAY CARDS
F07 PEPIN DD CARDS
F08 PEPIN SAMPLE INPUT
F09 EDIT JCL
F10 EDIT FORTRAN IV SOURCE
F11 EDIT DD CARDS
F12 PEPIN SAMPLE OUTPUT
F13 EDIT SAMPLE OUTPUT