Environmental Science, 10th Edition (Cunningham)

Chapter 19: Conventional Energy

GE Exercise: Three Mile Island Nuclear Power Plant

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An overview manual is available by clicking here... Google Earth Overview (342.0K)

To continue:
- Make sure you have the Google Earth software installed and running.
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- Hit "Enter" for Google Earth to take you to the specified coordinates, then come back here and read the following overview.

Latitude/Longitude: 40.1536, -76.7231

Overview: Three Mile Island Nuclear Power Plant, p. 440

In 1979, Unit 2 of the Three Mile Island nuclear power plant near Harrisburg, PA, suffered the most serious accident in U.S. commercial nuclear power history. The accident began about 4 AM on March 28, 1979, when feedwater pumps necessary for cooling steam generators failed. This prevented the steam generator from removing heat from the reactor core. As a consequence, the reactor began to overheat. As heat and pressure in the reactor increased, a pressure valve within the containment building opened. It should have closed when pressure dropped as the reactor shut down, but it didn't. Operators couldn't tell how much coolant remained in the reactor core. They thought the coolant levels were sufficient to prevent overheating, but they were wrong. They made matters worse by reducing the flow of coolant through the radioactive core. As a result, the nuclear fuel overheated and a partial meltdown occurred. About half the metal clad fuel pellets ruptured and melted. Fortunately, the molten fuel didn't breach the containment building (as happened seven years later at the Chernobyl Reactor in Ukraine).

A large-scale evacuation was ordered for nearby residents. A small amount of radiation escaped but health officials estimated that the average dose received by local residents averaged only about 1 millirem. To put this in context, a full set of chest x-rays results in about 6 millirems. Epidemiologists report that the effect on this large population would be statistically impossible to detect. Nevertheless, this accident played a powerful role in alerting the American public to the dangers of nuclear power. It brought about sweeping changes in emergency planning, reactor operator training, human factors engineering, radiation protection, and many other aspects of nuclear power. It marked the end of rapid expansion of this energy source in the United States.

You can find a more detailed history of Three Mile Island along with a plant diagram at the U.S. Nuclear Regulatory Commission (NRC) web page. In the Google Earth view, the large, hollow, cylindrical structures (note their shadow) are cooling towers. The twin nuclear reactors are shorter cylinders with domed tops. The buildings around the reactors are control rooms and sites for electrical generation.

1
What river runs around Three Mile Island?
A)Three Mile River
B)Susquehanna River
C)Pennsylvania River
D)Middleton River
E)China Syndrome River
2
How many nuclear reactors are at this facility?
A)One
B)Two
C)Three
D)Four
E)Five
3
Why is it advantageous for the nuclear plant to be located near a river or coastline?
A)It can supply potable water for the labor force.
B)Employees tend to live near rivers and coastlines.
C)Recreational access is a powerful employee motivator.
D)The climate is more temperate.
E)Water is needed for cooling nuclear reactors
4
How far is it from Three Mile Island to Philadelphia?
A)Close to 3 miles
B)About 10 miles
C)About 50 km
D)A little over 100 km
E)Almost 200 km
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