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