Aluminum nitride based in-core power monitor

This paper provides an overview and current status of an on-going International Nuclear Energy Research Initiative Project to develop a solid-state flux monitor. Since uncertainty in the local power peaking is likely to be operationally limiting to the fuel performance of high temperature reactors, the new sensor is intended to be deployed in-core, at power. The sensor essentially consists of polycrystalline aluminum nitride ceramic compact configured as a flux sensitive resistor. Neutrons interact through the ¹⁴N(n,p) ¹⁴C producing free electrical carriers as the daughter particles slow down within the sensor. The ceramic compact is a small (3 mm ² by ∼0.5 mm) high electrical resistance chip with direct bonded copper contacts on opposing sides, resembling a parallel plate capacitor. Bias voltage is applied to sweep the free carriers through the compact resulting in a current proportional to the dose deposited in the sensor body. Sensors have now been demonstrated in radiation fields.