Milestones: March 28, 2024
NUCLEAR ACCIDENT— THE THREE MILE ISLAND NUCLEAR POWER PLANT, BUILT IN 1974 NEAR HARRISBURG, PENNSYLVANIA, SUFFERED ONE OF THE NATION’S WORST ACCIDENTS OF THE INDUSTRY WHEN, AT 4 A.M. on March 28, 1979, a pressure valve in the Unit 2 Reactor failed to close. This set off a sequence of events, complicated by human error, that threatened an entire community with fatal radiation. However, that worst-case scenario was averted. After the pressure valve failure, cooling water with radiation contamination drained into adjoining buildings, causing the core to overheat, and cooling pumps were activated. The staff, confused by contradictory sensor readings, erroneously shut off the emergency water system while heat was still being released, thus causing an almost complete meltdown before they rectified that situation. However, the crisis was not over, and a bubble of highly flammable hydrogen gas that had formed was discovered two days later within the reactor building. A panic ensued.
President Jimmy Carter, who was trained in nuclear engineering while in the U.S. Navy, visited the plant on April 1, and ascertained that the bubble was not in danger of exploding. Preventive steps were taken, but the crisis caused the public to lose trust in nuclear energy.
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