i) You're correct in that venting the steam won't solve the cooling issues. Venting the steam is being considered in order to reduce the steam pressure in the p

i) You're correct in that venting the steam won't solve the cooling issues. Venting the steam is being considered in order to reduce the steam pressure in the primary system. If the pressure gets too high, then the primary system could rupture, resulting in an uncontrolled release of radiation. ii) I falsely conflated uncontrolled fission with meltdown in my explanation. Meltdown is when the core reaches a temperature at which the control rod cladding (which is probably stainless steel, though I can't confirm that) melts. Uncontrolled fission will result in a spectacular meltdown, as happened at Chernobyl. So, being shutdown is not a guarantee against melting down. However, as long as the core stays submerged, then it should stay cool enough to avoid melting down. I haven't read any reports that the operators are concerned about water level in the core, so a meltdown is unlikely. Worst case, you could open up a valve on the primary and stick a hose in it.