RSICC CODE PACKAGE CCC-670
1. NAME AND TITLE
VSOP94: Very Superior Old Programs - Computer Code System for Reactor Physics and Fuel Cycle Simulation.
Juelich Research Center, Juelich, Federal Republic of Germany Through the NEADB, France
3. CODING LANGUAGE AND COMPUTER
Fortran 77; VAX/VMS, IBM RISC 6000, DEC Alpha (C00670MNYWS00)
4. NATURE OF PROBLEM SOLVED
VSOP94 (Very Superior Old Programs) is a system of codes linked together for the simulation of reactor life histories. It comprises neutron cross section libraries and processing routines, repeated neutron spectrum evaluation, 2-D diffusion calculation based on neutron flux synthesis with depletion and shut-down features, in-core and out-of-pile fuel management, fuel cycle cost analysis, and thermal hydraulics (at present restricted to Pebble Bed HTRs). Various techniques have been employed to accelerate the iterative processes and to optimize the internal data transfer.
The code system has been used extensively for comparison studies of reactors, their fuel cycles, and related detailed features. In addition to its use in research and development work for the High Temperature Reactor, the system has been applied successfully to Light Water and Heavy Water Reactors.
5. METHOD OF SOLUTION
The nuclear data of 160 isotopes are contained in two libraries. Fast and epithermal data in a 68 group GAM-I structure have been prepared from ENDF/B, BNL-325, and, in special cases, from other sources. Resonance cross section data are given as input. The data currently used are the ones published by J. J. Schmidt and ENDF/B IV. Thermal data in a 30 group THERMOS structure have been collapsed from a 96 group GATHER library by a typical HTR neutron energy spectrum generated by the GATHER code. Graphite scattering matrices are based on the Young phonon spectrum in graphite.
The auxiliary codes DATA-2 and DATA-3 are specifically developed for HTRs. They prepare the input data for the nuclear part of the code from the basic geometric design figures for the fuel elements and reactor core, respectively.
The neutron spectrum is calculated by a combination of the GAM and THERMOS codes. They can simultaneously be employed for the many core regions differing in temperature, burn-up, and fuel element lay-out. The thermal cell code THERMOS has been extended to treat the grain structure of the coated particles inside the fuel elements, and the epithermal GAM code uses modified cross-sections for the resonance absorbers prepared from double heterogeneous ZUT-DGL calculations.
A two-dimensional neutron flux map is synthesized from a fast one-dimensional diffusion code in four energy groups by means of r-z iterations. This is used for the burnup calculation of up to 200 different compositions in the core. The basic scheme has been developed from the FEVER code. The build-up history of 40 fission product nuclides in these compositions is followed explicitly. The diffusion part of the program system will be repeated at many short burn-up stages, and the spectrum module will be reiterated at some larger time steps, when some significant change in the spectrum is expected.
The fuel management and cost module performs the fuel shuffling and general evaluations of the reactor and fuel element life history. The fuel management simulates the currently known shuffling and out of pile routes for various reactors. It has further been extended to include the typical features of the pebble bed reactor as burnup dependent optional reloading of elements, separated treatment of different fuel streams, and recycling in new fuel element types according to a consistent mass balance and timing.
Optionally, four different types of data files can be set up with characteristic data of the reactor life. These are used for more detailed investigations and display programs. The restart option allows the study of special phases of the reactor life, e.g., changes of the fueling scheme, of the burn-up, of the power output, of the coolant temperature, and of the corresponding KPD code. Two dimensional thermal hydraulics studies for operating and emergency conditions can be performed with the recently developed TIK-THERMIX code. A 2-dimensional display of incore characteristics is given by the LSD being coupled with TIK. LSD also given the averaged temperature of the different spectrum zones in the core.
6. RESTRICTIONS OR LIMITATIONS
The thermal hydraulics part of this system is presently restricted to Pebble Bed HTRs.
7. TYPICAL RUNNING TIME
Sample Run time on Dec Alpha (in seconds)
Sample Run time on IBM RISC (in seconds)
8. COMPUTER HARDWARE REQUIREMENTS
VSOP94 is operable on the VAX/VMS, IBM RISC 6000 under AIX 4.2.1, DEC Alpha under UNIX 4.0D. It was difficult to verify the test case results as the original VAX output was not supplied; however, the DEC and IBM RS/6000 output closely match.
9. COMPUTER SOFTWARE REQUIREMENTS
A Fortran 77 compiler is required. Operating systems on which VSOP was tested include VAX/VMS, IBM AIX 4.2.1 and DEC UNIX 4.0D.
B. L. Kirk, "README" (April 1999).
E. Teuchert, U. Hansen, K. A. Haas, H. J. Rutten, H. Brockmann, H. Gerwin, U. Ohlig, W. Scherer, "V.S.O.P. - Computer Code System for Reactor Physics and Fuel Cycle Simulation" - Input Manual and Comments (April 1994).
11. CONTENTS OF CODE PACKAGE
Included are the referenced document and a CD-ROM which contains the source files, scripts, data library and a test case. Machine specific tar files are included for each computer (VAX, DEC, IBM). The VAX files are also included in a self-extracting compressed DOS file.
12. DATE OF ABSTRACT
KEYWORDS: NEUTRON; ENDF FORMAT; FLUX or DOSE PLOTTING