Report Of The President's Commission On
The Accident At Three Mile Island           > TMI-2 > Kemeny

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Account of the Accident


The accident at Three Mile Island did not end with the breaking up of the bubble, nor did the threat to the health and safety of the workers and the community suddenly disappear. A small bubble remained, gases still existed within TMI-2's cooling water, and the reactor itself was badly damaged. Periodic releases of low-level radiation continued, and some feared a major release of radioactive iodine-131 might yet occur. Schools remained closed. The Governor's recommendation that pregnant women and preschool children stay more than 5 miles from the plant continued.

Saturday, March 31, the Department of Health, Education, and Welfare had arranged for the rapid manufacture of nearly a quarter million bottles of potassium iodide.122 That same day, the Pennsylvania Bureau of Radiation Protection -- which had originally accepted HEW's offer to obtain the drug -- transferred responsibility for handling the radioactive iodine blocker to the state's Department of Health. Gordon MacLeod, who headed the health department, put the drug shipments in a warehouse as they began arriving Sunday. During the weekend, Thomas Gerusky, director of the Bureau of Radiation Protection, requested that his people at TMI be issued potassium iodide; Gerusky wanted BRP personnel to have the thyroid-blocking agent available should a release of radioactive iodine occur. MacLeod refused. He argued that if the public learned that any of the drug had been issued, a demand for its public distribution would result.

MacLeod had the backing of the Governor's office and Harold Denton in his decision not to issue the potassium iodide. The decision did not find agreement in Washington, however. On Monday, Jack Watson asked HEW to prepare recommendations for the drug's distribution and use. These were developed by a group headed by Donald Frederickson, director of the National Institutes of Health. The recommendation included: administering potassium iodide immediately to all workers on the Island; providing the drug to all people who would have less than 30 minutes' warning of a radioactive iodine release (roughly those within 10 miles of the plant); and that local authorities assess these recommendations in light of their first-hand knowledge of the situation.

Governor Thornburgh received the recommendations in a White House letter on Tuesday, although some Pennsylvania officials had learned of them Monday. MacLeod strongly opposed distributing the drug to the public. Among his reasons: radioiodine levels were far below what was indicated for protective action, and the likelihood of a high-level release from TMI-2 was diminishing; distributing the drug would increase public anxiety and people might take it without being told to do so; and the possibility of adverse side-effects presented a potential public health problem in itself. MacLeod chose not to accept the federal recommendations. The potassium iodide remained in a warehouse under armed guard throughout the emergency. In midsummer, the FDA moved the drug to Little Rock, Arkansas, for storage.                           '


Tuesday, April 3, General Public Utilities, Met Ed's parent company, established its TMI-2 recovery organization to oversee and direct the long process of cleaning up TMI-2. Robert Arnold, a vice president of another subsidiary, the GPU Service Corporation, was named to head the recovery operation.123

Wednesday, April 4, schools outside the 5-mile area surrounding TMI reopened. All curfews were lifted. But schools within 5 miles of the Island remained closed and the Governor's advisory remained in effect for pregnant women and preschool children.

Some sense of normalcy was gradually returning to the TMI area. Governor Thornburgh asked Denton repeatedly if the advisory could be lifted, allowing pregnant women and preschool children to return home. But the NRC wanted some specific event as a symbol to announce the crisis had ended. At first, the NRC looked to reaching "cold shutdown" the point at which the temperature of TMI-2's reactor coolant fell below the boiling point of water. When it became obvious that cold shutdown was days away, agreement was reached between Pennsylvania's Bureau of Radiation Protection and the NRC on ending the advisory. On Saturday, April 7, Kevin Molloy, at the request of the Governor's office, read a press release announcing the closing of the evacuation shelter at the Hershey Park Arena. Not until 2 days later, however, did Governor Thornburgh officially withdraw the advisory.124


The accident at TMI did not end with cold shutdown, nor will it end for some time. More than a million gallons of radioactive water remain inside the containment building or stored in auxiliary building tanks. The containment building also holds radioactive gases and the badly damaged and highly radioactive reactor core. Radioactive elements contaminate the walls, floors, and equipment of several buildings. Ahead lies a decontamination effort unprecedented in the history of the nation's nuclear power industry a cleanup whose total cost is estimated at $80 to $200 million and which will take several years to complete.125

The initial cleanup began in April. Using a system called EPICOR-I, Met Ed began decontaminating pre-accident water stored in the TMI-1 auxiliary building, which contains low levels of radioactivity (less than one microcurie per milliliter). Efforts to decontaminate the TMI-2 diesel generation building began in April and work on the auxiliary and fuel handling buildings got under way in May. This involves mostly dry and wet vacuuming, mopping, and wiping of radioactive areas to remove the contamination ~- a task that requires special clothing and respirators to protect workers.

The accident and its subsequent cleanup already have produced a variety of solid, slightly radioactive wastes, such as clothing, rags, ion-exchange resins, swipes, and contaminated air filters. To date, 12 truckloads of these wastes have been hauled to Richland, Washington, and buried at a commercial disposal site.

But the more difficult aspects of decontamination -- both technically and politically -- lie ahead. Met Ed has asked the NRC for permission to release the krypton-85 in the air of the containment building into the atmosphere in controlled bursts. The releases would come over a 2-month period to ensure that off-site radiation does not exceed the NRC's limits for routine operation of a nuclear power plant.

Much of the contaminated water left from the accident -- some 600,000 gallons pooled in the containment building and about 90,000 gallons in the reactor coolant system -- contains high levels of radioactivity (in excess of 100 microcuries per milliliter). Met Ed had stored 380,000 gallons of water containing intermediate levels of radioactivity (1 to 100 microcuries per milliliter) in several TMI-2 auxiliary building tanks. Over the summer, the utility installed a system called EPICOR-II to treat this water. NRC approved its use, provided that the resins used to remove radioactive materials from the water were solidified before shipment from the Island to a disposal site. Met Ed began decontaminating the intermediate water in mid-October.

Until radioactive gases are removed from the containment building, no human entry into the sealed structure can be made. Meanwhile, detailed plans for entry and assessing conditions inside the building are being developed. Because no one knows the exact condition of the reactor vessel or its core, no detailed plans have been made for handling and removing its damaged core.

Thus, the accident at Three Mile Island, in a very real sense, continues and will continue until the years-long cleanup of TMI-2 is completed. Workers will receive additional radiation doses until the decontamination process is completed; five workers in late August, for example, received doses in excess of the NRC's quarterly limits for exposure to the skin or the extremities. And there still remains some risk to the general public that released radiation could escape from the Island.