GAMSOR: Gamma Source Preparation and DIF3D Flux Solution (Rev. 2)

Abstract

DOE) reports produced after 1991 and a growing number of pre-1991 documents are available free at OSTI.GOV (http://www.osti.gov/), a service of the US Dept. of Energy's Office of Scientific and Technical Information.

Gamma Source Verification for GAMSRC and GAMSOR

“…Given the difficulty involved in preparing the data for Excel, it should be clear that accidentally obtaining results that match GAMSRC is unlikely. With this work done successfully on all three cases with differing geometry, the GAMSRC calculation of the gamma source is correct and consistent with the procedure stated to be used in the manual [1].…”

“…The GAMSOR [1] program is a modified version of DIF3D [2] used to obtain the coupled neutron gamma flux distributions for a given reactor system. GAMSOR was first developed in the 1980s and its work has progressed in parallel with DIF3D throughout its various development phases.…”

“…While GAMSOR is compatible with DIF3D-FD and DIF3D-Nodal, DIF3D-VARIANT [3] is most commonly used today and will be the focus of the present verification effort. As covered in the methodology manual [1], GAMSOR [4] was built to provide more accurate heating distributions by explicitly solving for both the gamma and neutron heating distributions. Without this consideration, gamma heat is normally assumed to be deposited locally at the site of gamma production.…”

Software Verification of VARPOW

“…The Superenergy-2 software was designed to take a user power distribution as input along with basic assembly geometry details and assembly flow specifications. The SE2ANL software is effectively a wrapper around Superenergy-2 which handles the interface with DIF3D (as part of GAMSOR [7]) to obtain the pin power details that Superenergy-2 needs as input. There is no such wrapper with DASSH.…”

“…The PMATRX file stores the neutron and gamma heating cross section data and the GHFLUX file stores the gamma flux moments, while the ISOTXS file stores just the neutron cross section data and a energy conversion factor. The reader is referred to reference [7] for further details on the cross section data setup and differences between these approaches. The preferred approach for defining the power for DASSH and SE2ANL is to use GAMSOR as it properly distributes the gamma heating throughout the modeled domain.…”