I spy with my little satellite something starting with N
Thermal Identification
The above discussion was more features oriented for identification of sites and a bit less scientific, but we have set a reasonable ground of site identification from the above example. Adding to the discussion, it will be very important to monitor the status of military reprocessing plants that were shutdown under Fissile Material Cut-off Treaty (FMCT).
For understanding such scenarios more reliable results are required, that can be achieved using thermal infrared sensors operating in infrared wavelength region (8-14 micrometers in atmospheric window) to reveal heat signatures (as absence of ice in previous example) (Fig. 3).
Fig 3. Atmospheric Transmission at various Wavelengths
Fig 4. 1m resolution IKONOS satellite image (captured Feb 2000) of heavy water production facilities near Khushab reactor site, Pakistan. (credit: spaceimaging.com)
If the reprocessing plant is closed the activity level must be very low but a very small scale reprocessing plant again requires TIR imaging. So removal of heat from reactor core is essential for shutdown, that is, no vaporization is occurring (no water-vapor plume visible as in UK's site). As already discussed if reactor has cooling pond TIR can still indicate the change in temperature. If the reactor is using water of river through ports, the temperature variance of water from input stream to discharge stream is a clear indicator (Fig. 5).
Fig 5. Four Calderhall Magnox reactors at Sellafield, United Kingdom. The four reactors made a significant contribution to the UK's plutonium for weapons.Source: http://www.fas.org/nuke/guide/uk/facilit
