When this occurs there is a rapid rise in temperature and pressure within the reactor causing emergency vent valves to open in {HEAD ~ order} to reduce {TAIL ~ the pressure} within the reactor and vent the reactor contents 
to reduce
When this occurs there is a rapid rise in temperature and pressure within the reactor causing emergency vent valves to open in { HEAD ~ order } to reduce { TAIL ~ the pressure } within the reactor and vent the reactor contents
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH