Example embodiments are directed to tiered tie plates and fuel bundles that use tiered tie plates. When the total of said operations reaches a fixed value, the security circuit is prevented from operating until it is re-initialized again. The frame carries deck portions extending substantially between the lower end and the upper end. A control signal selects one of the amplified primary channel signal, the non-amplified primary channel signal, the amplified diversity channel signal or the non-amplified diversity channel signal. Each diode mount is adapted to retain a respective diode in a thermally conductive manner.