About the HELCZA facility

HELCZA is an experimental facility designed

for cyclic high-heat-flux loading

The device is equipped with an electron beam gun with a maximum output power of 800 kW. At the maximum acceleration voltage of 55 kV the electron current exceeds 14 A. HELCZA is primarily intended for

full-size testing of the ITER FW modules, divertor inner vertical targets and ICRF antenna screens with a surface area up to 2.2 m2 and with

a power deposition density up to 20 MW/m2 for unlimited cycles.

The potential maximum surface which can be thermally loaded

in HELCZA exceeds 4 m2 depending on the test specimen geometry.

A beam scanning frequency of 20 kHz in horizontal and vertical direction with the primary deflection angle of up to 40° from the gun axis provides very uniformity of the surface heating.

HELCZA is equipped with a 3D kinematic system for FW panel tilt and rotation allowing the incidence angle of the beam relative to the tested surface to be adjusted. A mock-up holder with connections for cooling of the modules allows automatic programmable positioning of the mock-ups with a weight of up to one ton during the testing. The handling of the mock-ups is performed by a manipulation system of the mock-up on the rail transporter and the gantry crane. The vacuum vessel has a volume of 13 m3. Testing is carried out in high vacuum in the range from 10−3 Pa to 10−1 Pa.

High vacuum is obtained by a set of mechanical and cryogenic pumps, constant pressure is maintained by regulated influx of a working gas (N2). Maximal operational parameters of the cooling water that the HELCZA facility is able to provide are temperature of up to 320 °C, pressure of up to 15 MPa and flow rate of up to 40 m3/h. The standard operational parameters are temperature up to 150 °C and pressure up to 5 MPa. For example, the cooling parameters for ITER first-wall modules testing are inlet temperature of 70 °C, pressure of 3.16 MPa and flow rate of 21 m3/h.

Diagnostics and management

All technological devices are monitored and controlled by a central diagnostic and control system. The key monitored parameters

of samples are the surface temperature, the calorimetric measurement of absorbed heat flux and other test sample parameters (e.g. flatness

of the applied heat flux) and device protection related parameters

(e.g. sudden vacuum level increase, cooling pressure loss, vacuum chamber overheating etc.). The diagnostics of HELCZA facility consist of infrared cameras, High-res cameras, X-ray camera, one and two-colours pyrometers, thermocouples, flow meters and manometers.

The infrared cameras are of two kinds. Medium wavelength infrared cameras (MWIR) monitor the surface temperature distribution

in a spectral range of 3–5 µm within the range from 0 °C up to 2,000 °C

at a full resolution of 1024 × 1024 pixels.

Long wavelength infrared cameras (LWIR) for surface temperature monitoring measure in a spectral range 7.5–14 µm within the temperature range from 0 °C up to 2,000 °C at a full resolution

of 1024 × 768 pixels. The one-colour pyrometer monitors

in a temperature range from 0 °C to 1,000 °C. The first two-colour pyrometer monitors surface temperatures from 500 °C to 1,400 °C,

and the second two-colour pyrometer records temperatures from

750 °C to 2,400 °C. X-ray camera ensures the precise localization

of the electron beam impact onto the surface where bremsstrahlung

is triggered. The X-ray camera is used as primary diagnostic for heat flux uniformity monitoring. High-resolution cameras observing the test area in a visible range is able to record at a full resolution of 2560 × 2160 pixels.

Controled area

Chemical controlled area is a complex of inter-connected rooms. These rooms were designed to prevent migration of toxic dust particles between them and in particular to prevent contamination of environment. High power HVAC system put in place differential pressure system, which aims to capture the main contamination in the centre of controlled area which especially includes the vacuum vessel area. This complex indicates that it is fully compliant for handling with carcinogenic beryllium dust which is generated during high heat flux loading of ITER-like first wall panels.