I have just found out that you can't shut down the reactor. More specifically, you can shut down the preheaters and the reactor will eventually cool down and generate no more power, and then you can safely shut down the solenoid and the toroid VDGs, but - and Reika confirmed this - there is no way to flush the remaining fusion plasma from the containment pipes so that you can shut down the VDGs powering the pipes without getting a lava lake. I can't see how anyone can NOT see this as a critical design flaw. I have no intention of working on a system with the constant threat of drowning in lava when I point my pickaxe the wrong way hanging over my head. Unfortunately, the pipes are also the most distributed subsystem, so it's basically impossible to make its power failsafe and the only other method - breaking the pipes - is also unfeasible because of the wide distribution and the fact that some pipes are within multiblock structures. I've thought of ending the project because of this. However, I just succeeded in building the main component, it would be sad to let it go now, so instead, I will being doing this: I will revert to a pre-startup backup and revise my cheating policy. With any new feature I add, I will revert to a pre-startup backup after I've successfully built it and tested it if necessary, and for anything that requires a power level where I'd need the reactor to have run, I will cheat. I already spent several hours filling an auroral battery twice, and testing power-down conditions also took hours since it takes so long for the preheaters to cool down, and inevitably all my power-down tests ended in lava. I will not be doing that again. No more progress for today since I have RL obligations... One good thing though: apart from having a functional reactor, I think I have so far succeeeded in integrating the reactor site into the landscape in an aesthetically pleasing way.