Tapping the hot plume would not penetrate the magma chamber. They would drill down and created a number of holes turned horizontally in the hot rock zone above

Tapping the hot plume would not penetrate the magma chamber. They would drill down and created a number of holes turned horizontally in the hot rock zone above it. They would then drill a number of holes horizontally - which they would fracture(frack) and inject cold water - in one set and get steam from another. The steam used in turbines and then returned. Minerals and ions would make this water very corrosive and the pipe alloys would be chosen for long life(?). As to whether or not they can reduce volcano risk = accurate models and assessment of the existing heat flux that now makes Yellowstone bubble might give some ideal of any hope for success. In any event, they should at least create and study these models and assess in the rate of migration of the hop spot - since it is a slowly changing steady state, it may be that removing enough heat can change when the next eruption occurs. The actual magma may be too hot for pipes to carry water in as the metal may be so close to the melting point that they will explode from the flash steam. An intermediate heat transfer fluid could be used(such as melted sodium) to get closer to the hotter zones with a lower risk of pressure explosions. The other aspect is what % of the heat could be extracted this way - if it is 0.1% - it might not be worthwhile. The Icelandic ongoing work in this area is worth looking into.