A dry cask storage system (DCSS) structured to contain therein an amount of spent nuclear fuel, the DCSS comprising: a vessel having a wall that is formed of a metallic material and that is formed to have a first interior region, the first interior region being structured to receive therein the SNF; a overpack that is formed of a cementitious material and that is formed to have a second interior region, the vessel being received in the second interior region; a detection apparatus that is cooperable with an electronic processing apparatus that is situated outside of the DCSS, the detection apparatus comprising a transmitter, an electrical circuit apparatus, and a receiver; the transmitter being positioned inside the second interior region and outside the vessel and being structured to generate an excitation pulse and to transmit the excitation pulse through the wall and into the first interior region; the electrical circuit apparatus having a resonant electrical circuit that is situated within the first interior region and that is structured to generate a response pulse in response to the excitation pulse and to transmit the response pulse in the form of a magnetic field signal that is structured to travel from the first interior region and through the wall; the resonant electrical circuit comprising a plurality of circuit components, at least one circuit component of the plurality of circuit components having a property which is structured to vary in response to a condition within the first interior region and which, responsive to a change in the condition, is structured to cause the property and the response pulse to vary with the change in the condition and to be indicative of the condition; and the receiver being situated inside the second interior region and outside the vessel, the receiver being structured to receive the response pulse and to communicate to the electronic processing apparatus an output responsive to the response pulse. a vessel having a wall that is formed of a metallic material and that is formed to have a first interior region, the first interior region being structured to receive therein the SNF; a overpack that is formed of a cementitious material and that is formed to have a second interior region, the vessel being received in the second interior region; a detection apparatus that is cooperable with an electronic processing apparatus that is situated outside of the DCSS, the detection apparatus comprising a transmitter, an electrical circuit apparatus, and a receiver; the transmitter being positioned inside the second interior region and outside the vessel and being structured to generate an excitation pulse and to transmit the excitation pulse through the wall and into the first interior region; the electrical circuit apparatus having a resonant electrical circuit that is situated within the first interior region and that is structured to generate a response pulse in response to the excitation pulse and to transmit the response pulse in the form of a magnetic field signal that is structured to travel from the first interior region and through the wall; the resonant electrical circuit comprising a plurality of circuit components, at least one circuit component of the plurality of circuit components having a property which is structured to vary in response to a condition within the first interior region and which, responsive to a change in the condition, is structured to cause the property and the response pulse to vary with the change in the condition and to be indicative of the condition; and the receiver being situated inside the second interior region and outside the vessel, the receiver being structured to receive the response pulse and to communicate to the electronic processing apparatus an output responsive to the response pulse.