5.1.1. Acknowledgements

Development and maintenance of ORIGEN and related codes and methods have been sponsored by many organizations including the US Nuclear Regulatory Commission (NRC), the US Department of Energy (DOE), and nuclear power and research institutions.

5.1.2. Version Information

The ORIGEN (Oak Ridge Isotope Generation) code [ORIGEN-Bel73] was developed at Oak Ridge National Laboratory (ORNL) to calculate nuclide compositions and radioactivity of fission products, activation products, and products of heavy metal transmutation. Since 1991, ORIGEN has been developed as the depletion/decay module in SCALE with support from the NRC. ORIGEN in SCALE is the only version supported at ORNL, and it supersedes all earlier versions. The following is a brief description of the major enhancements in each version. Data are described in the ORIGEN Data Resources chapter. Version 6.3 (2021)

Code Responsible(s): W. A. Wieselquist

Contributors: W. Wieselquist, S. Hart, K. Bledsoe, S. Skutnik, K. Bekar

Continued modernization focused on incorporating the capabilities of COUPLE into the ORIGEN sequence, improved data formats, and interoperation with ENDF-formatted data. The main new feature is a nuclear data sensitivity capability. Version 6.2 (2016)

Code Responsible(s): W. A. Wieselquist

Contributors: W. Wieselquist, S. Hart, A. Isotalo 1, F. Havlůj 2, S. Skutnik, R. Lefebvre, I. Gauld, D. Wiarda, J. Lefebvre, G. Hu 4, N. Sly 3, and D. Lago 5

A major modernization effort for ORIGEN was initiated by I. Gauld in 2011 and has resulted in approximately 5 person-years of effort refactoring the ORIGEN and related codes to be more efficient and easily testable. The major enhancements and responsible parties are listed below.

  • Extensive refactor and modernization of Fortran 77 to Fortran 90+ performed by F. Havlůj, including substantial extension of the output capability

  • Implementation of an alpha and beta spectrum calculation by F. Havlůj and I. Gauld

  • Introduction of C++ core data structures with Fortran bindings, implemented by S. Skutnik using R. Lefebvre’s C++/C/Fortran binding generator created for this purpose

  • Testing suite developed by S. Skutnik, W. Wieselquist, D. Lago, and N. Sly

  • Standardization of codebase while developing application programming interface (API) for high-performance depletion in the Consortium for Advanced Simulation of Light Water Reactors (CASL) and Nuclear Energy Advanced Modeling and Simulation (NEAMS) projects performed by W. Wieselquist

  • Unification of readers/writers for ORIGEN data files developed by W. Wieselquist

  • Improvement of binary formats for the ORIGEN library (f33) and ORIGEN concentration file (f71) by J. Lefebvre, R. Lefebvre, and W. Wieselquist

  • Implementation of Chebyshev Rational Approximation Method (CRAM) solver by A. Isotalo

  • Development of new input format (ORIGEN sequence only) by S. Hart and W. Wieselquist using the SCALE Object Notation (SON) syntax developed by R. Lefebvre

  • Improvement of cubic spline interpolation scheme for ARP by S. Skutnik and W. Wieselquist with monotonicity fix-up determined by G. Hu

  • Major revision of manuals by W. Wieselquist, combining ORIGEN, ARP, COUPLE, and OPUS into a single manual

Additional guidance provided by D. Wiarda and I. Gauld with testing by J. W. Hu. Version 6.1 (2011)

The following section acknowledgements appeared in the SCALE 6.1 manual. ORIGEN

Code Responsible(s): I. C. Gauld

The ORIGEN code was first developed by M. J. Bell with contributions from J. P. Nichols and other members of the Chemical Technology Division at ORNL. Development of the ORIGEN code as a depletion module of the SCALE code system was performed by O. W. Hermann with contributions from R. M. Westfall, supported by the NRC. COUPLE

Code Responsible(s): D. Wiarda and I. C. Gauld

The COUPLE code was originally developed by O. W. Hermann with guidance from staff members including L. M. Petrie, N. M. Greene, W. E. Ford III, and R. M. Westfall, who contributed greatly to formulation of the methods, design of the data library interface with other modules, and testing. Many valuable suggestions concerning code applications were received from J. C. Ryman, J. R. Knight, and E. J. Allen. ARP

Code Responsible(s): I. C. Gauld, S. M. Bowman, and J. E. Horwedel

The authors thank S. B. Ludwig for his support in earlier stages of this work. The authors are grateful for the technical advice received from B. L. Broadhead, M. D. DeHart, N. M. Greene, O. W. Hermann, C. V. Parks, L. M. Petrie, and J. C. Ryman. The authors thank Germina Ilas and Georgeta Radulescu for reviewing the manual and Willena Carter for preparation of the manuscript. OPUS

Code Responsible(s): I. C. Gauld and J. E. Horwedel

The work of O. W. Hermann in developing the PLORIGEN program, from which OPUS was later developed, and the work of D. L. Barnett in developing the original version of PlotOPUS, are acknowledged. Appreciation is extended to J. C. Ryman for his review and testing of the program. Finally the authors thank S. J. Poarch for formatting the manuscript.


Aalto University, Finland


ÚJV Řež, a. s., Czech Republic


University of Tennessee, Knoxville


University of Illinois, Urbana-Champaign


Georgia Tech