Hydrodynamic Characteristics of Coolant Flow in Bundles of Ribbed Fuel Rods Located with Increased Pitch of Spacing

The numerical simulation offluid flow in 7- and 37-rod fuel assemblies is carried out. Fuel rods are spaced by two-rib wrap with different fin steps and distance between rods. The rod constructions of this type are offered to use in cores of fast fission reactors with lead coolant. Information about the flow structure in bundles, mass transfer characteristics is obtained and generalized. It is shown, that the mass transfer in bundles is determined by the Froude number while a pressure drop coefficient of the bundles depends on the Reynolds number and Froude number. It is found that a periodic change in the passage area of fuel assemblies results in uneven distributions of the static pressure over the surfaces of rods. This pressure unevenness increases as the fin step decreases.

References

[1] Dragunov Yu.G., Lemekhov V.V., Smirnov V.S., Chernetsov N.G. Technical solutions and development stages for the BREST-0D-300 reactor unit. At. Energy, 2012, vol. 113, no. 1, pp. 70-77. doi: 10.1007/s10512-012-9597-3

[2] Adamov E.O., Dragunov Y.G., Orlov V.V. Mechanical engineering for nuclear technology, Book 1. In: Mashinostroenie. Entsiklopediya. Tom 4 [Mechanical engineering. Encyclopedia. Vol. 4]. Moscow, Mashinostroenie Publ., 2005, pp. 667672 (in Russ.).

[3] Kirillov P.L., Yur’ev Yu.S., Bobkov V.P. Spravochnik po teplogidravlicheskim raschetam (Yadernye reaktory, teploobmenniki, parogeneratory) [Handbook on thermal-hydraulic calculations (Nuclear reactors, heat exchangers, steam generators)]. Moscow, Energoatomizdat Publ., 1984. 296 p.

[4] Belov I.A., Isaev S.A. Modelirovanie turbulentnykh techeniy [Simulation of turbulent flows]. St. Petersburg, Balt. Gos. Tekh. Univ. Publ., 2001. 108 p.

[5] STAR-CCM+, version 7.04. User Guide, CD-adapco Group, 2012.

[6] Getya S.I., Krapivtse V.G., Markov P.V., Solonin V.I., Tsirin S.I. Modeling temperature nonuniformities in a fuel-element bundle of a VVER-1000 fuel-assembly. At. Energy, 2013, vol. 114, no. 1, pp. 69-72. doi: 10.1007/s10512-013-9673-3

[7] Patankar S.V. Numerical heat transfer and fluid flow. Hemisphere Publ., 1980. 197 p. (Russ. ed.: Patankar S. Chislennye metody resheniya zadach teploobmena i dinamiki zhidkosti. Moscow, Energoatomizdat Publ., 1984. 152 p.).

[8] Davydov Yu.I., Dzyubenko B.V., Dreytser G.A. Teploobmen i gidrodinamika v kanalakh slozhnoy formy [Heat transfer and hydrodynamics in channels of complex shape]. Moscow, Mashinostroenie Publ., 1986. 200 p.