The visual inspection of a package can give information both on the structural integrity and on the contamination level of the package. It can be carried out either directly or indirectly. Direct visual inspection is simply viewing the package through a shielded window filled with oil. The thickness of such window is approximately 1.2m . The indirect visual inspection consists of use of different types of cameras and robotics. The most common methods are the following:
‘Fixed CCTV cameras’
‘Endoscope with built in camera’
‘Master/Slave Manipulator (MSM) held CCTV’
‘Crawler camera’ is a camera mounted on radio controlled robotic crawler that moves around the ‘inspection’ cell, sending images to a remote monitor . ‘Fixed CCTV cameras’ are cameras fixed inside the inspection cell at the base, mid-height, and above a package inspection area. The ‘Endoscope with built in camera’ is based on the same principles as the ‘Fixed CCTV cameras’ but the camera is routed from the ‘cold’ to ‘hot’ side through the Inspection Cell wall .
‘Master/Slave Manipulators held CCTV camera’ are mechanical arms that reach into the ‘hot’ area holding a CCTV camera. Workers on the ‘cold’ side will operate these MSMs and they will be able to observe the package. They are already used with great success at the current waste retrieval facility at Nirex UK .
Figure 2: Schematic of Endoscope [Error: Reference source not found]
Measuring the corrosion levels is a direct way of checking each package for possible corrosion, uniform or localised. Corrosion sensors are already used in industry to measure corrosion levels in pipes or other structures made out of metals. The sensors are mounted n straps which are strapped in the suspicious areas of the package [Waste Package Monitoring Technical Report (Section 1.1)].
Figure 3: Typical corrosion sensor used in a decaying pipe [Waste Package Monitoring Technical Report (Section 1.1)]. CHLORIDE SENSORS
Chloride is a form of chlorine and is found in most natural water. It is the primary contaminant of concern which results in different types of localised corrosion 
Although chloride levels are expected to be controlled within the vaults, measurements on individual packages will indicate the likelihood of corrosion for the specific package. If high chloride levels are observed this may indicate that the corresponding area of the vault may also contain high levels and require further investigation.
Chloride levels can be measured in many ways such as wet-chemistry (titration), correlation with electrical conductivity measurement, colorimeters,  and chloride Ion-Selective Electrodes (ISE).
Figure 4: Measure of chloride levels using ISE .