UWB Subsurface Radar With Antenna Array for Imaging Of Internal Structure Of Concrete Structural Elements
The basic design principals implemented in the advanced UWB radar with time-domain operation and with the 100 - 900 MHz effective band are considered including real synthetic array and full-polarimetric schema. The radar is installing on a moveable platform for remote operation on the territories with radioactive pollution. This probing system should be employed near the nuclear power plant block No. 4 of the Chernobyl nuclear power plant near Kyiv. Ukraine, damaged in 1986. The key task is searching and localisation of the nuclear-fuel contained materials (NFCM) inside the Cascade Wall around nuclear reactor. The testing of the presented UWB radar is in progress now.
Basically the problem to locate NFCM inside the concrete Cascade Wall can be solved by nonstandard ground penetrating radar (GPR) technique rather than by commercially available radars. The challenger features of the treated problem involve:
- sounding medium is thick up 10 meters and more layered concrete medium:
- this medium has strong signal attenuation depended on internal water/ionic content:
- it is inhomogeneous medium due to chaotic internal filling with a large variety of different objects including elements of the destroyed reactor dispersed by explosion:
- NFCM should be detected can be as solidified masses of molted concrete with patches of radioactive substances:
- it is expected that in some cases those patches may have a cylindrical shape as original fuel-assemblies:
- searching areas on the horizontal plane of the Cascade Wall have rectangular shape where edge regions near vertical walls will cause strong diffraction interference (figure 1):
- only completely automatic radar operation can be possible due to radioactive pollution of searching areas.