CRX - A CODE FOR RECTANGULAR AND HEXAGONAL LATTICES BASED ON THE METHOD OF CHARACTERISTICS

Authors
Citation
Sg. Hong et Nz. Cho, CRX - A CODE FOR RECTANGULAR AND HEXAGONAL LATTICES BASED ON THE METHOD OF CHARACTERISTICS, Annals of nuclear energy, 25(8), 1998, pp. 547-565
Citations number
18
Categorie Soggetti
Nuclear Sciences & Tecnology
Journal title
ISSN journal
03064549
Volume
25
Issue
8
Year of publication
1998
Pages
547 - 565
Database
ISI
SICI code
0306-4549(1998)25:8<547:C-ACFR>2.0.ZU;2-4
Abstract
A transport theory code CRX based on the method of characteristics wit h a general geometric tracking routine for rectangular and hexagonal g eometrical problems is developed and tested for heterogeneous cell and assembly calculations. Since the method of characteristics uses the c haracteristic form of the Bolzmann transport equation, CRX has no prac tical limitations placed on the geometry of the problem and gives accu rate solutions in strongly absorbing media. To relax the constraints o f the existing charateristic transport calculation codes, a new, treat ment of the reflective condition is introduced. In this treatment, the external reflective boundary is discretized into small segments and t he angular fluxes for rays along a segment are assumed to be uniform. Also, a new calculational procedure for condensation is devised to obt ain an accurate energy spectrum of absorber cells. after the character istic cell calculation, an S-N transport calculation is performed for the assembly comprised of homogenized cells. The result is used to cal culate group and angular octant dependent albedos on absorber cell bou ndaries. Then, the two-dimensional characteristic transport calculatio n with the albedo boundary conditions is performed again for absorber cells. Using the condensed group macroscopic cross sections, a two-dim ensional characteristic transport calculation is performed for the het erogeneous assembly. To test the code, it is applied to several benchm ark problems which consist of complex meshes and compared with other c odes. The results show that the CRX code is very accurate. (C) 1998 El sevier Science Ltd.