Detection apparatus comprising a resonant electrical circuit located within a nuclear fuel rod

A fuel rod for use in a nuclear reactor, the fuel rod comprising:

• a cladding defining an interior region;
• fuel pellets housed in the interior region;
• a pressure transmission apparatus configured to measure pressure within the fuel rod;
• and
• a resonant electrical circuit within the interior region of the cladding,
• wherein the resonant electrical circuit is configured to generate a pulse structured to travel wirelessly from the interior region through the cladding,
• wherein a frequency of the pulse varies based on pressure within the fuel rod measured by the pressure transmission apparatus, and
• wherein the frequency of the pulse is indicative of the pressure within the fuel rod.