ATTILA: A three-dimensional, unstructured tetrahedral mesh discrete ordinates transport code
- Los Alamos National Lab., NM (United States)
Many applications of radiation transport require the accurate modeling of complex three-dimensional geometries. Historically, Monte Carlo codes have been used for such applications. Existing deterministic transport codes were not applied to such problems because of the difficulties of modeling complex three-dimensional geometries with rectangular meshes. The authors have developed a three-dimensional discrete ordinates (S{sub n}) code, ATTILA, which uses linear-discontinuous finite element spatial differencing in conjunction with diffusion-synthetic acceleration (DSA) on an unstructured tetrahedral mesh. This tetrahedral mesh capability enables the authors to efficiently model complex three-dimensional geometries. One interesting and challenging application of neutron and/or gamma-ray transport is nuclear well-logging applications. Nuclear well-logging problems usually involve a complex geometry with fixed sources and one or more detectors. Detector responses must generally be accurate to within {approx}1%. The combination of complex three-dimensional geometries and high accuracy requirements makes it difficult to perform logging problems with traditional S{sub n} differencing schemes and rectangular meshes. Hence, it is not surprising that deterministic S{sub n} codes have seen limited use in nuclear well-logging applications. The geometric modeling capabilities and the advanced spatial differencing of ATTILA give it a significant advantage, relative to traditional S{sub n} codes, for performing nuclear well-logging calculations.
- OSTI ID:
- 426394
- Report Number(s):
- CONF-961103--
- Journal Information:
- Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 75; ISSN TANSAO; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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