Heating the chamber and valve would get rid of the loose water. New water is formed continuously with every shot as the oxygen from the tungsten oxide is released and combines with the deuterium fuel. Tungsten oxide is a surprisingly complex material. The color and temperature of the tungsten oxide reveals its oxygen content. Temperatures above 550 degrees C in a hydrogen atmosphere can remove the surface oxide layer. See the references here and here.
The reinforcing structure can’t take those temperatures. So coating the electrode surfaces with silver seems to be a reasonable solution.
