Hydrodynamic characteristics of an experimental model of the target in the MK-1 liquid-metal target system

In this report, the dynamic response of a liquid metal target container for pulsed spallation neutron sources have been simulated using both a commercial code and a self-developed program. The main features and differences of both programs are presented. A transient thermal analysis was first examined with coupled and uncoupled heat equations. Temperature distribution results showed that the coupling effect between two pulses can be neglected. Stress waves due to direct pulsing have been calculated on the target container, investigating the effects of loading rate and structure thickness. Results from the transient thermal-structural analysis showed that, due to inertia effects, the dynamic stress in the target container is contributed mainly from direct heating in the initial time stage, and later from the pressure wave in the target liquid as it reaches the container wall.

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REGULARITIES OF FORMATION OF FLOW OF COOLANT BEHIND THE TVS-KVADRAT MIXING SPACING GRID OF THE PWR-TYPE REACTOR

ENERGETIKA Proceedings of CIS higher education institutions and power engineering associations ◽

10.21122/1029-7448-2019-61-3-258-268 ◽

2018 ◽

Vol 61 (3) ◽

pp. 258-268

Author(s):

S. M. Dmitriev ◽

D. V. Doronkov ◽

M. A. Legchanov ◽

V. D. Sorokin ◽

A. E. Khrobostov

Keyword(s):

Fuel Assembly ◽

Experimental Model ◽

Experimental Studies ◽

Coolant Flow ◽

Hydrodynamic Characteristics ◽

Experimental Investigations ◽

Thermal Reliability ◽

Flow Rates ◽

Type Reactor ◽

Active Zones

Tgratinghis paper presents the results of experimental investigations of the influence of mixing spacer gratings with different types of deflectors on the coolant flow in the TVSKvadrat fuel assembly of the PWR-type reactor. Experimental model of the TVS-Kvadrat of the PWR reactor was made in complete geometric similarity with the full-scale cassettes. Studies were carried out by modeling the flow of coolant in the core with the use of an experimental stand; the latter was an aerodynamic open loop through which air is pumped. To measure the local hydrodynamic characteristics of the coolant flow, special pneumatic sensors were used that were able to measure the full velocity vector at the point by its three components. During the studies of the local fluid dynamics of the coolant, the transverse flow rates were measured; also, the coolant flow rates were measured by cells of the TVS-Kvadrat experimental model. The analysis of the spatial distribution of the projections of the absolute flow velocity made it possible to detail the pattern of the coolant flow behind the mixing spacing gratings with different variants of the deflector design, as well as to choose the deflector of the optimal design. Accumulated data base on the flow of the coolant in the TVS-Kvadrat fuel assembly formed the basis of the engineering justification of the structures of the active zones of PWR reactors. Guidelines for choosing optimal designs mixing spacing grids have been considered by designers of the “Afrikantov OKBM” JSC when they created implementations of the latest TVS-Kvadrat assemblies. The results of experimental studies are used to verify CFD-codes of both foreign and domestic origin, as well as the programs for detailed cell-by-cell calculation of active zones in order to reduce conservatism in the justification of thermal reliability.

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