The internal components of the RPV, figure 2, are the core, the HL riser, the Upper Plenum (UP), the Pressurizer (PRZ), the SG primary side, the Cold Leg (CL) downcomer and the Lower Plenum (LP). The RPV shell is covered by Thermo-12 hydrous calcium silicate insulation.

The core is modelled with 56 cylindrical heater rods distributed in a 1.86 cm pitch square array with a 1.33 pitch to diameter ratio. The nominal power of each heater rod is 7.1 kW resulting in a maximum core power of 398 kW. The diameter of the core rod is 1.59 cm.

A lower core flow plate, figure 3, contains 76 auxiliary flow holes of 0.635 cm of diameter, arranged at 1.86 cm pitch square array, and 57 core rod flow holes. In order to create a flow annulus between the flow plate and the core rod, the holes of the rodded lower core flow plate are oversized at 1.72 cm.

The core is shrouded, figure 4, to ensure all flow enters the core via the bottom and travels the entire heated length. The shroud is shaped to partially block the primary coolant flow through the outermost auxiliary flow holes in order to ensure that each heated rod receives approximately equal axial coolant flow. The amount of blockage is dependent on the number and location of heated rods adjacent to each auxiliary flow hole. At mid elevation a core grid wires is considered in order to maintain the radial alignment of the core rods. Four thermocouples for measuring the core inlet temperatures are located at the bottom CL entering the core. The core heater rod temperatures are measured. Six thermocouples vertically spaced every 15.24 cm measuring water temperatures, are located in the center of core thermocouple rod. The pressure loss in the core is measured; the power to the core heater rod bundles is measured.

The HL riser, figure 2, consists of a lower region, an upper region and a transition region. The lower region consists of a pipe with an outside diameter of 20.32 cm, an inside diameter of 19.71 cm and a wall thickness of 0.305 cm. The upper region consists of a pipe with an outside diameter of 11.43 cm, an inside diameter of 10.23 cm, and a wall thickness of 0.602 cm. The transition region consists of a cone with a 0.305 cm thickness and an half angle of 20.61°. The pressure loss between core top and riser cone, the pressure loss in the riser cone and the pressure loss in the chimney, from the exit of the transition cone to the UP, are measured. Along the riser a thermocouple measures the water temperature inside chimney below SG coil and another one measures the water temperature at top of chimney. The flow rate within the HL chimney is measured with a differential pressure cell used to measure flow. The primary containment water level is measured as well.

06.35mm flow holes

Equally spaced on 18.59mn

Square Pitch (76)

017.20mm Hecrter Rod Flow Hole (56)

017,20mm Thermocouple Rod Flow Hole (1)

18.59ПП

The UP is separated from the heated upper PRZ section by a thick baffle plate having eight 2.54 cm holes, spaced uniformly around the baffle plate periphery, which allow free communication of the PRZ to the remainder of the RPV during normal operation and for volume surges into and/or out of the PRZ due to transients.

The PRZ is integrated in the RPV and is located in its upper part. In the PRZ are located three heater elements, each 4 kW, that are modulated by the test facility control system to maintain nominal primary system pressure at the desired value. The PRZ steam temperature and pressure are measured. The PRZ level is measured as well.

The CL downcomer region, figure 2, is an annular region bounded by the RPV wall on the outside and the HL riser on the inside, and the flow area reduces at the HL riser cone. In the SG primary side section is inserted the SG helical coil bundle. Thermocouples are located in the CL downcomer region to measure water down flow temperatures after SG coils. The primary side pressure loss across SG and the pressure loss in the annulus below SG are measured.

The SG of the facility is a once through heat exchanger and is located within the RPV in the annular space between the HL riser and the inside surface of the RPV. The tube bundle, is a helical coil consisting of fourteen tubes with a total heated length of 86 m. There are three separate parallel coils of stainless steel tubes. The outer and middle coils consist of five tubes each while the inner coil consists of four tubes. The value of the degree of the steam superheat is changed in order to control the facility. A thermocouple is located at the exit of each helical coil. The main steam pressure and temperature are measured. The main steam mass flow rate is measured with a vortex flow meter. The FW supply in the SG outer, middle and inner coil mass flow rate are measured with flow Coriolis meters. The related pressures are measured. The FW temperature is measured as well.