Erosion/corrosion of machinable Tungsten in water

It was recently discovered that significant erosion/corrosion occurs with machinable tungsten when exposed to water, particularly when the water has dissolved oxygen present. The problem was first discovered about 1 1/2 years ago when extensive corrosion was found inside the cooling channels of the L5-80 white-beam slits located in sector 3-ID-A. Figure 1 and Figure 2 show cut-away sections of the tungsten slit; the water passages are severely corroded from the cooling water used to cool the slit. The problem was brought to the attention of the world's two largest manufacturers of machinable tungsten, Mi-Tech Metals from Indianapolis, IN and Kulite Tungsten Corp. from East Rutherford, NJ. Neither company had any experience with this problem and were unaware that water could cause such significant corrosion, apparently the APS was the first customer to ever use the material in this fashion