Experimental study of the axial velocity of lead coolant flow in a ring-shaped gap with different oxidizing potential

Abstract

The objective of the present work was to investigate experimentally the flow velocity of lead coolant in a ring-shaped gap on horizontal and vertical experimental sections during monitoring and regulation of the thermodynamic activity of oxygen. The experiments were motivated by an interest in validating the concept of the BREST-OD-300 fast reactor, in which a lead melt is to be used.The experiments were performed on an experimental stand. The stand contained experimental sections -horizontal and vertical with sensors for measuring the local velocity in the ring-shaped channel (Fig. 1). The low rate of the liquid metal was monitored with a magnetic flowmeter and by the volume method -calibration flow container; the thermodynamic activity of oxygen in the lead was monitored by sensors placed in flow and buffer containers. The equipment and pipelines were made of 08Kh18N10T steel and are electrically heated and possess thermal insulation.The sensors for measuring the flow velocity of the lead coolant were placed in two experimental sections: vertical and horizontal.The vertical section consisted of two coaxially arranged pipes (d 2 /d 1 = 4.2). The outer pipe, 45 mm in diameter, 2.5 mm thick, and 1570 mm long, was made of 12Kh18N10T austenitic steel. The inner pipe consists of a 2100 mm long tubular electric heater with a regular BREST-OD-300 fuel-element cladding made of 16Kh12MVSFBAR-Sh ferrite-martensite steel and a 1600 mm long active part. The flow direction in the ring-shaped gap is bottom to top.The horizontal section tilts at an angle of 3°along the direction of motion of the lead in the form of two coaxially positions pipes (d 2 /d 1 = 2.35). The outer tube is 1348 mm long, 45 mm in diameter, and 2.5 mm thick and consists of 12Kh18N10T austenitic steel. The inner pipe is 2095 mm long, 17 mm in diameter, and 3 mm thick; this pipe is a regular tube of a steam generator in the BREST-OD-300 reactor and is made of 10Kh9NSMFB ferrite-martensite steel.The sensor makes it possible to measure the potential and full head of the liquid-metal flow. The local velocity is calculated from the difference of these heads. The full head was measured with a capillary (tube with inner diameter 1 mm and wall thickness 0.25 mm), whose free end was directed opposite to the coolant flow. The coolant flows through the capillary and the system of pipes into the tank used to measure the full head. The potential head was measured through an opening in the wall of the experimental section. The free end of the capillary and the opening, for measuring the head, in the wall are located in the same transverse section of the tube. The lead flows through the measuring opening and through the system of pipes into the tank for determining the potential head.Using nuts, the entrance end of the capillary is moved in the radial direction over the cross section of the channel by means of a spacing plate. The plate is connected with a tie rod, whose other end is secured to a probe with the open end of the capillary.

Experimental Studies of Heat Transfer Characteristics and Properties of the Cross-Flow Pipe Flow Melt Lead

“…At the present time, specialists in the Russian Federation are engaged in designing fast neutron reactor installations cooled by lead and lead-bismuth coolants (heavy liquid-metal coolants); developments of such reactor installations are also under way in other countries. Previously, the NNSTU conducted research of heat-exchange characteristics in heavy liquid-metal coolants under conditions of longitudinal flow of heat-transfer tubes [1]- [3].…”

“…The equipment and pipelines coming in contact with lead and lead-bismuth coolants are made of steel of 08Х18Н10Т type, are electrically heated and heat-insulated. The volume of the lead coolant in the loop is approximately 0.12 m 3 , and the volume of the lead-bismuth coolant in the loop is approximately 0.6 m 3 . The lead and lead-bismuth flow rates are controlled by magnetic flow meters periodically calibrated by the gage tanks.…”

“…The experimental research of heat-exchange characteristics as well as temperature and velocity fields in a heavy liquid-metal coolant flow was carried out under the following operating parameters: lead coolant temperature Т = 450˚C -500˚C; controlled and regulated content of thermodynamically active oxygen impurity in alloy a = 10 −5 -10 0 ; lead flow through test section Q = 3 -6 m 3 -Experimental determination of velocity and temperature fields in the lead coolant flow.…”