Three Mile Island Nuclear Power Plant Essay

INTRODUCTION On March 28, 1979 the Three Mile Island Nuclear power plant owned by General Public Utilities, experienced at partial meltdown of its reactor core, after the initial failure of a pilot-operated relief valve (PORV) at the top of the pressurizer above its reactor core. Resulting in the evacuation of the citizens within a 10-mile radius of the plant. The sheer number of instruments and alarms in the control room and the inability of the operators to identify the priority of the alarms, then interrupt the meanings of those alarms, contributed to the incorrect conclusion to shut off the cooling system to the reactor. Thus, creating a situation in which the reactor was no longer being cooled, resulting in the partial melting of its

This in turn gives a false reading to the operators because of past issues of the same pumps turning on for no reason to shut them down in fear of flooding the pressurizer, the very thing the operators were trained to prevent. When the operators in the control shut down the pumps several things happen almost simultaneously, the reactor continues to generate heat, the “fail safe” safety mechanism of the control rods being inserted is activated, and fission left over from months of running the reactor still generates enough heat which continues to boil away the remaining coolant in the reactor. The coolant boiling away is in turn then turned into a vapor and released out through the stuck PORV valve at the top of the reactor. So, what is actually occurring in the reactor is the opposite of what the operators think is going on. Instead of the reactor being cooled by the water remaining in the pressurizer it is in fact boiling away and becoming less and less exposing more of the reactor, creating more and more of a hazard. From 4:05am until 6:00am “The operators disbelieve the various indications of serious trouble (including rising levels of radiation in the reactor buildings). Lacking any direct indicator of the water level in the reactor, they fail to grasp what is happening: the uranium fuel, intensely hot, is reacting