The Phase I program successfully demonstrated that heat exchanger relevant structures could be uniformly coated using Atomic Layer Deposition and that the these coatings could address corrosion issues with stainless steel and superalloy materials in SC-CO2 environments. Tests at the University of Wisconsin demonstrated that ALD-coated SS316 exhibited better corrosion resistance than Inconel 625, suggesting that lower cost ferritic materials can be substituted for superalloys in many applications. Preliminary thermomechanical analysis indicated that these coating can survive the static and cyclic stresses incurred in high pressure, high temperature systems, resulting in robust, long-term operation. More extensive analysis and testing will be required to confirm these results. More information.
The Phase I program successfully updated the design of CCR loads to meet the current ITER specifications. Rotating ferromagnetic and non-metal vacuum seals were eliminate, as were all brazed vacuum joints, and the design does not use corrosive materials in the coolant system. Detailed thermal analysis indicates the new design can safely absorb the incoming RF power without exceeding allowable material stresses. The electronic control system was redesigned to incorporate the latest technology for system monitoring and control. Analysis indicates the load can provide the same, highly reliable performance as CCR’s previous loads. To obtain further information, click on these links: Inner Cylinder Cooling, Inner Cylinder Stresses, Heating of the Cone, Wobble Load Life Test.
Corrosion Mitigation for RF Sources and Components
CCR is teamed with N.C. State University (NCSU) to develop corrosion mitigation coatings for RF sources and components used by the U.S. Navy. Issues with water quality in the fleet are causing increased corrosion and serious lifetime reduction of critical defense systems. CCR and NCSU are using Atomic Layer Deposition (ALD) to coat interior coolant surfaces with a thin layer of ceramic to separate the base metal from the coolant, thereby reducing corrosion and erosion. The effectiveness of this technique has been confirmed using accelerated life testing. SEM photographs of ceramic coatings can be found here.