National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Fuel Cycle Methods: First-Order Spherical Harmonics Formulations Capable of Treating Low Density Regions.

DE2004821070

Publication Date	2003
Personal Author	Smith, M. A.; Palmiotti, G.; Lewis, E. E.
Page Count	56
Abstract	In this report we present an approach to deal with a problem encountered in different type of systems and specific configurations: the treatment of low density regions. This is the case of gas cooled reactors, voided configurations (evaluations of associated reactivity coefficients), beam region of external source driven systems, etc. The approach is to form the nodal response matrix using the first-order form of the transport equation, for then the cross section no longer appears in the denominator, as in the case of the standard formulation of the VARIANT code. Two different formulations are presented: the differential and integral ones. After applications to different difficult benchmark problems, it was concluded that the new formulations can treat low density regions.
Keywords	Fuel cycle Cross sections Transport Benchmarks Low density regions
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Northwestern Univ., Evanston, IL. Dept. of Mechanical Engineering.; Argonne National Lab., IL.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Argonne National Lab., IL. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200413

Fuel Cycle Methods: First-Order Spherical Harmonics Formulations Capable of Treating Low Density Regions.

Fuel Cycle Methods: First-Order Spherical Harmonics Formulations Capable of Treating Low Density Regions.
DE2004821070

Publication Date	2003
Personal Author	Smith, M. A.; Palmiotti, G.; Lewis, E. E.
Page Count	56
Abstract	In this report we present an approach to deal with a problem encountered in different type of systems and specific configurations: the treatment of low density regions. This is the case of gas cooled reactors, voided configurations (evaluations of associated reactivity coefficients), beam region of external source driven systems, etc. The approach is to form the nodal response matrix using the first-order form of the transport equation, for then the cross section no longer appears in the denominator, as in the case of the standard formulation of the VARIANT code. Two different formulations are presented: the differential and integral ones. After applications to different difficult benchmark problems, it was concluded that the new formulations can treat low density regions.
Keywords	Fuel cycle Cross sections Transport Benchmarks Low density regions
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Northwestern Univ., Evanston, IL. Dept. of Mechanical Engineering.; Argonne National Lab., IL.; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Argonne National Lab., IL. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200413