Abstract: One or more devices and/or methods provided herein relate to a method for fabricating a filtering electronic device having a co-integrated impedance modification element and signal transmission line. An electronic structure can comprise a circuit board, and a first plate and a second plate retaining the circuit board therebetween, wherein the first plate and the second plate each have a cryogenic thermal contraction rate that is lower than a cryogenic thermal contraction rate of the circuit board. In one or more embodiments, a silicon chip can be physically coupled to the circuit board by a plurality of solder bumps and disposed between the first plate and the second plate.

Abstract: In a gas cooled nuclear reactor, cesium metal release into the coolant gas is dependent on the coolant channel surface temperature in the core. The present invention relates to a filter for removing cesium from the coolant gas before it passes to the heat exchanger. The filter comprises a block or blocks of graphite having holes therein with a hydraulic diameter between 1 mm and 6 mm and a ratio of length to equivalent hydraulic diameter between 170 and 1000. This filter is arranged at one end of the reactor core so that the gases pass straight from the core into the filter block.