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The 5 Biggest Nuclear Weapons Tests (from All 6 Nuclear Powers)

These days, the phrase nuclear test is almost synonymous with North Korea. After all, Pyongyang has conducted six nuclear tests since its first one in 2006. No other country has conducted a single test this century.

In the grand scheme of things, however, North Korea is barely a blimp on the map. Between America’s first nuclear test in 1945 and North Korea’s last denotation in September of last year, the world has witnessed at least 2,056 nuclear tests. Nearly 85 percent of these were conducted by the United States and the Soviet Union, but the three other recognized nuclear powers (the United Kingdom, France and China) have also conducted a significant amount of their own. Israel has never officially tested a nuclear weapon, although there is strong evidence that it secretly tested some in South Africa in 1979. India conducted a “peaceful” nuclear explosion in 1974, followed by a series of five nuclear blasts in May 1998. Later that same month, Pakistan responded with six nuclear tests on two seperate days.

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Not all nuclear tests are created equal though. Some blasts produce yields of tens or hundreds of tons of TNT equivalent, while others have measured in the tens of megatons (a megaton is equal to a million of tons). Variance is greatest among the two Cold War superpowers, but the United Kingdom, France, China and North Korea have also had some significantly different yields in their nuclear tests. With that in mind, let’s look at the biggest nuclear blasts of each of these countries.

The United States

The United States has the distinction of both conducting the first and most nuclear weapons tests in history. Washington memorably conducted its first nuclear test, the Trinity, in the New Mexico desert on July 16, 1945. Upon witnessing the blast, which measured in at twenty kilotons (20,000 tons of TNT equivalent), Dr. J. Robert Oppenheimer famously declared, “Now I am become death, destroyer of worlds.”

America was just getting started. Between the 1945 and 1992, the United States conducted 1,030 nuclear tests, nearly half of the world’s total. Its largest one came just nine years after the Trinity test on March 1, 1954 at the Bikini Atoll in the Marshall Islands. The Castle Bravo design used was intended to be the first deliverable thermonuclear weapon after the United States had first tested a hydrogen bomb in 1952.

Castle Bravo turned into a major catastrophe. While the designers were expecting a yield in the range of 5–6 megatons, the resulting blast was an incredible fifteen megatons. That is roughly 1,000 times more powerful than the bombs used against Japan in World War II. The resulting fallout quickly turned into an international disaster for the United States, as the radiation spread out over roughly 7,000 square miles, according to some sources. Perhaps most notably, a Japanese fishing boat, Lucky Dragon No. 5, happened to be in the area and twenty-three of its crew members would die in short order due to radiation poisoning.

The test also brought the danger of the nuclear era into sharp relief for United States and other world policymakers. After the test, President Dwight D. Eisenhower’s science advisers superimposed the fallout patterns of the Castle Bravo test on a map with Washington, DC as ground zero. The results were shocking. As Annie Jacobsen recounts in her fantastic book on the history of DARPA:

If ground zero had been Washington, D.C…. every resident of the greater Washington-Baltimore area would now be dead…. Even in Philadelphia, 150 miles away, the majority of inhabitants would have been exposed to radiation levels that would have killed them within the hour. In New York City, 225 miles north, half of the population would have died by nightfall. All the way to the Canadian border, inhabitants would have been exposed to 100 roentgens or more, their suffering similar to what the fisherman on the Lucky Dragon had endured.

Soviet Union

The Soviet Union didn’t conduct the first or the most nuclear tests. In total, the Soviet Union oversaw 715 tests compared to America's 1,030. Where Moscow did outdo Washington was in the size of its tests. In fact, of the five largest nuclear blasts in history, all were conducted by the Soviet Union.

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