TMI 25 Years Later: The Three Mile Island Nuclear Power Plant Accident and Its Impact

1. The main feedwater system that supplies water to the steam generator malfunctioned and shutoff flow. "Water must be fed continually to the steam generators to make up for the flow of steam from the steam generators to the turbine. 2. Maintenance was being performed on the condensate polishing system. The polishing system is used to purify water in the feedwater system. 3. Alarms went off. An auxiliary feedwater system should have started automatically but it did not. The auxiliary system was to provide emergency source of cooling water to the steam generators, however, critical valves in the system were left closed. Without this critical water supply, the boiling water in the steam generators would boil away completely. A rapid rise in temperature and pressure occurred in the reactor's cooling system. 4. The turbine shutdown automatically. 5. Within seconds, the reactors control system shut down the reactor by dropping the control rods which insulate the neutrons generated from the U235 from striking other U235 atoms in adjacent fuel rods. The fission process stopped. 6. As temperatures and pressures rose water flowed into the pressurizer. The pressurizer is normal half full providing a cushion for expansion from the reactor. A power-operated relief valve also help control pressure during abnormal events. 7. A pressure-regulating valve opened to reduce pressure in the reactor and associated reactor systems. 8. Steam began flowing from the valve through piping into a collecting tank in the basement of the reactor containment building. The water was containinated with radioactive material. The flow caused the pressure to decrease. 9. The pressure regulating valve should have closed but it didn't. The operators had no way of monitoring the valve and therefore did not know it remained open. 10. Vital cooling water was flowing from the reactor out through the valve to the basement collecting tank. The tank overflowed spilling water on the basement floor and was pumped to storage tan in the adjacent building outside the containment building. 11. The emergency core cooling system started automatically. 12. The water level and volume in the reactor system was not measured directly. The operators relied on a measurement of the water level in the system's pressurizer. The operators thought there was adequate water inventory in the primary cooling system. Fearing the system might go solid (rupture from the reactor being 100 filled with water), they turned off the emergency core cooling system. 13. Pressure dropped from the escaping core water. By 5:30 am, the pressures had dropped so low that the large reactor coolant pumps used to circulate the water through the reactor and primary system began to vibrate. 14. The operators began shutting down the pumps to reduce damage. 15. Water began pouring onto the floor of the auxiliary building and radioactive gases found their way from the cooling water through the auxiliary building

I have read extensively on the Three Mile Island accident and believe that this book is probably the best introduction to the accident I have yet seen. The book is accurate and is scrupulously unbiased, which is a rarity in any book dealing with nuclear power. The first 32 pages of the book provide the best and most concise general overview of the accident I have read, and anyone wanting to understand the accident should start here. The book is accessible to non-specialists, but does not make inaccurate generalizations simply for ease of explanation. There is information presented on the basic concepts of nuclear energy, which makes the book extremely valuable to someone just beginning to read on the issue. More knowledgeable readers, industry professionals, and policymakers benefit from this book as well, as it has chapters on the health effects of the accident (including recent data on ongoing longitudinal studies), environmental effects of the accident, policy effects of the accidents, and perhaps most usefully, excellent appendices which include a useful glossary, an accident timeline, and a list of common misconceptions about the TMI accident. The authors have done an admirable job of writing a book that is useful to both professionals and the general public. It is extremely well documented, non-political, unbiased, and scrupulously accurate. I highly recommend this book to anyone interested in nuclear power.

"Objective knowledge will help provide guidance for the decisions that will need to be made as we go forward into the next quarter-century." So ends the book TMI 25 Years Later, an objective, inclusive compilation of information regarding the March 28, 1979 Loss-of-Coolant Accident in Reactor 2 of the Three Mile Island Nuclear Plant near Middletown, PA. The book, written by three Penn State University staffers, offers a balanced, condensed history of the events of the accident and the years of follow-up that have occurred. Sections cover all aspects of the accident, including rather extensive review and analysis of the role played by the media in the event. Other topics covered include short- and long-term physical and psychological health effects, industry regulatory and financial impacts, and environmental consequences, along with current and future power requirements in the United States and the options for meeting those requirements. In order to properly understand exactly what caused the accident and what it's effects meant to the local population, a rudimentary understanding of nuclear processes and power generation are needed. Complex nuclear concepts are presented in an illustrated, easy-to-understand manner, and an in-depth minute-by-minute timeline of the accident is presented along with causes, effects, and notes that only the luxury of extensive investigation and hind-sight can provide. An excellent book for anyone interested in nuclear power generation, the TMI accident or the local populace of the plant, TMI 25 Years Later provides condensed information in an easy-to-read format. The information is not watered down (the book is well cited), but instead provided in a format that allows anyone to understand what happened on that fateful Wednesday morning, and more importantly what it means to our future.