Three mile island NUCLEAR MELTDOWN 1979

1. Three mile islandNUCLEAR MELTDOWN 1979 Rachael Naeger Melissa Elliott Jenna Clack Alyssa Bryant

2. Introduction • Middletown, Pennsylvania • May 1968 Three Mile Island (TMI) Unit 1 Construction began • November 1969 TMI Unit 2 Construction began • Unit 1 began operation in September 1974 • Unit 2 started up in December 1978 • Within 90 days, on March 28, 1979, a nuclear meltdown occurred in TMI 2 • A non-nuclear failure led to a nuclear meltdown • Worst accident at a nuclear power plant in the history of U.S. commercial power plants

3. Nuclear reactor Main Components • Fuel Source: Uranium • Moderator to slow the release of neutrons of the Uranium • Typically water • Control rods to absorb neutrons and control the rate of reaction • Coolant to transfer heat from the reactor core • Steam generator that is part of the coolant system • Containment to protect outside from radiation and core from foreign particles

4. Process description • Reactor splits atoms of elements to release heat • Splits the Uranium atoms • Moderator slows the release of neutrons and control rods absorb neutrons • Heat is captured in gas or water (the coolant) • Transfer from the reactor to steam generator • This is used to create steam • The steam is used to drive a turbine and create electricity

5. TMI Unit 2 Diagram

6. Timeline • Video • 4:00 AM March 28, 1979 • Initial Problem - Secondary cooling circuit stopped flowing • Valves closed due to water leak into air line • Secondary pipes boiled dry • Prevented primary coolant from removing heat from core • Automatic shutdown occurred • Relief valve in primary loop failed to close • Two valves manually closed two weeks prior for maintenance so water unable to flow • Loss of coolant occurred and relief valve opened • Plant experienced: uncovered core, hydrogen gas generation, radioactive primary coolant on reactant-building floor

7. Timeline (continued) • Pressure in primary unit was high • Operators over-rode emergency core-coolant systemand shut off pumps • Valves closed for cleaning were opened to move cooling water into boiling region, but water turned to steam • Pumps began to vibrate • Operators shut down pumps and ended forced cleaning to prevent damage to pumps • Temperatures failed to decrease due to gas and hydrogen pockets in system • Operators had gas transferred to hold-up tanks in another building • Pipe transferring gas leaked to atmosphere • Sudden build-up in pressure indicated hydrogen burn occurred • Operators periodically opened vent in the reactor to cool slowly (one month) • Cooled by natural movement of water, no mechanical movement

8. Evacuation • Inadequate evacuation plans in place • At first, no evacuation was called for • Public confusion • On Friday, March 30, Governor called for a limited evacuation

9. Ultimate Results • No fatalities or injuries • Radiation exposure ~ 0.3 - 0.6 rem • No conclusive evidence for an increase in cancer cases • Unit 2 not allowed to resume operation • Unit 1 not allowed to resume operations until 1985 • General Public Utilities paid $82 million as compensation • Negative media coverage • Property values dropped • Mistrust of Nuclear Industry • Loss of income for surrounding farms

10. Clean-UP • Lasted 14 years • Vented 44,000 curies of radioactive gases • Water decontamination • Removal of solid waste • Cost ~ $1 billion

11. Lessons Learned • New Regulations • Inherently Safer Design and Operation • Emphasis on Training and Transparency • Creation of INPO • Expect the Unexpected

12. Summary • Worst Nuclear Industry accident in U.S. history • No injuries or fatalities • Major changes to the industry • New research into what causes a core meltdown • Fed public mistrust of nuclear industry

13. References • 1Kemeny, John G. The Accident at Three Mile Island. Rep. Washington D.C., 1979. The Accident at Three Mile Island. Web. 23 Feb. 2012. <http://www.threemileisland.org/downloads/191.pdf>. • 2 "Backgrounder on the Three Mile Island Accident." NRC:. Web. 23 Feb. 2012. <http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html> • 3 "Three Mile Island Accident." Three Mile Island. Web. 01 Mar. 2012. <http://world-nuclear.org/info/inf36.html>. • 4 Del, Tredici Robert. The People of Three Mile Island. San Francisco: Sierra Club, 1980. • 5 Flynn, Cynthia B. The Social and Economic Effects of the Accident at Three Mile Island. Rep. no. NUREG/CR-1215. Print. • 6Osif, Bonnie A., Anthony John Baratta, and Thomas W. Conkling. TMI 25 Years Later: The Three Mile Island Nuclear Power Plant Accident and Its Impact. University Park, PA: Pennsylvania State UP, 2004. • 7 "Backgrounder on the Three Mile Island Accident." NRC:. Web. 01 Mar. 2012. <http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html>. • 8 King, Lester J., and James H. Opelka. "Three Mile Island Cleanup: Experiences, Waste Disposal, and Environmental Impact." 213.78 (1982). • 9 Walker, J. Samuel. Three Mile Island: A Nuclear Crisis in Historical Perspective. Berkeley: University of California, 2004. Print. • 10 "News." Three Mile Island: 30 Years of What If ... Web. 01 Mar. 2012. <http://www.pittsburghlive.com/x/pittsburghtrib/news/multimedia/s_617234.html>. • 11Toth, L. M. The Three Mile Island Accident: Diagnosis and Prognosis : Developed from a Symposium Sponsored by the Division of Nuclear Chemistry and Technology at the 189th Meeting of the American Chemical Society, Miami Beach, Florida, April 28-May 3, 1985. Washington, D.C.: American Chemical Society, 1986. Print. • 12 Hargreaves, Steve. "First New Nuclear Reactors OK'd in over 30 Years." CNNMoney. Cable News Network, 09 Feb. 2012. Web. 01 Mar. 2012. <http://money.cnn.com/2012/02/09/news/economy/nuclear_reactors/index.htm>. • 13Greenwire, PETER BEHR,. "Three Mile Island Still Haunts U.S. Nuclear Industry." The New York Times. The New York Times, 27 Mar. 2009. Web. 01 Mar. 2012. <http://www.nytimes.com/gwire/2009/03/27/27greenwire-three-mile-island-still-haunts-us-reactor-indu-10327.html?pagewanted=all>.

14. Questions?