Directional {theta}-weighted differencing scheme for pressure vessel fluence calculations

Journal Article · Sun Dec 31 04:00:00 EST 1995 · Transactions of the American Nuclear Society

OSTI ID:411741

Petrovic, B; Haghighat, A ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States)

To ensure the reactor pressure vessel integrity it is necessary to accurately determine/predict the fast neutron fluence (E > 0. 1 MeV) within the pressure vessel. The standard methodology consists of two-dimensional/one-dimensional multigroup S{sub N} calculations, three-dimensional flux synthesis, and consolidation of calculated and measured results. The DORT code is used for the S{sub N} calculations. Extensive sensitivity studies have been performed to assess the accuracy and uncertainties of this methodology; they have revealed inherent numerical difficulties and anomalies in the S{sub N} solutions. The consequence of these anomalies is an additional uncertainty in the S{sub N} results, which is higher than all the other {open_quotes}regular{close_quotes} S{sub N} uncertainties combined, and which is relevant for practical fluence considerations. It has been shown that these numerical difficulties are caused by the multigroup differencing schemes and a new directional {theta}-weighted differencing scheme (DTW) has been developed to alleviate them. This paper examines the application of the DTW scheme to the pressure vessel fluence calculations.

• OSTI ID: 411741
• Report Number(s): CONF-951006--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 73; ISSN TANSAO; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
66 PHYSICS
ACCURACY
CALCULATION METHODS
D CODES
DISCRETE ORDINATE METHOD
FLUX SYNTHESIS
NEUTRON FLUENCE
PRESSURE VESSELS