Analysis of the Chernobyl accident

Conference · Wed Dec 31 23:00:00 EST 1986 · Trans. Am. Nucl. Soc.; (United States)

OSTI ID:5534923

Heck, C L; Hochreiter, L E; Huang, P; Stolmar, A

The unfortunate accident at Chernobyl Unit 4 has indicated the strong feedback effects that coupled neutronics and thermal-hydraulics core have for some reactor designs. To better understand the accident and to provide an independent assessment of the accident scenario given by Soviet scientists, Westinghouse has attempted to model the Chernobyl RBMK reactor using its safety analysis system computer codes. Before the RBMK reactor could be modeled, a coarse, three-dimensional reactor kinetics model (FASTAR), which was under development at Westinghouse, was integrated into the Westinghouse small-break loss-of-coolant accident code, NOTRUMP. The FASTAR neutronic model uses a single neutron energy and six neutron precursor groups and includes reactivity feedback from the graphite moderator, fuel rods, and the coolant in both the fuel assemblies and the control channels. FASTAR was coupled directly to the NOTRUMP thermal-hydraulics calculation to provide the calculated core power history as a function of the reactor coolant conditions. The NOTRUMP code uses a five-equation two-phase flow thermal-hydraulic model with thermal nonequilibrium and a drift flux formulation. The analysis presented does support the Soviet explanation of the Chernobyl accident scenario as a plausible cause and shows the extreme coupling of the core neutronics and hydraulics for this reactor design.

• OSTI ID: 5534923
• Report Number(s): CONF-870601-
• Journal Information: Trans. Am. Nucl. Soc.; (United States), Journal Name: Trans. Am. Nucl. Soc.; (United States) Vol. 54; ISSN TANSA
• Country of Publication: United States
• Language: English

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