Roger Hanson: New Zealand well aware of nuclear fallout from pacific testing

Thursday, 26 October 2017

No matter where a bomb is detonated, nuclear fallout is an issue, the closer to the detonation site the more concentrated and therefore dangerous the fallout.

Opinion: Veteran Pacific correspondent Mike Field, speaking on Radio New Zealand's Nine to Noon programme, was somewhat bemused by the US ambassador, Scott Brown's comments; he said that New Zealanders fail to realise the risk of nuclear weapons in the Pacific and think they are too far away to be affected if Kim Jong Un decides to drop a hydrogen bomb in the Pacific. Mike Field pointed out that after 67 US, nine British and 193 French tests in the Pacific, New Zealanders are fully aware of the consequences of nuclear tests.

**READ MORE:

A Mark IV 'Fat Man' nuclear bomb, of the type lost by a US Air Force B-36 bomber on a training mission off the coast of British Colombia, Canada

* Roger Hanson: How the first nuclear weapons were developed

* Roger Hanson: The haunting question about North Korea's missiles**

There are two ways to generate the explosive energy of a nuclear reaction; atomic fission and atomic fusion. A fission bomb derives its explosive power from the huge energy released when atoms of uranium or plutonium are split. On the other hand a fusion bomb derives its power from the energy released when atoms, usually hydrogen, are combined (fused). Fusion bombs are up to 1000 times more powerful than fission bombs. The fusion process requires enormous temperatures to detonate the reaction and this is usually provided by a fission explosion. Hydrogen fusion bombs are called thermonuclear bombs.

In various locations across the globe between 1945 and 1996, more than 2000 fission and fusion nuclear bomb tests were conducted by several countries including the United States, the Soviet Union, China, the UK, France and India. About 500 of these were atmospheric tests, usually from towers or balloons or dropped from aircraft and detonated at altitudes below 15 kilometres. The rest were either underground tests to depths of up to 2400 metres or underwater to depths of 600m. There have been about 20 high altitude tests from 40km and as high as low space at 540km. One of these, Starfish Prime, in 1962 was exploded 400km above and south west of Hawaii. The accompanying electromagnetic pulse surged through the atmosphere, knocking out electronic and electrical systems in New Zealand. The explosion ionized the atmosphere over a wide area and created an artificial Aurora Borealis which was witnessed over New Zealand.

Not all Pacific nuclear tests went to plan. In 1954 the US tested its Castle Bravo atmospheric hydrogen bomb on Bikini Atoll in the Marshall Islands. The blast delivered 2.5 times more energy than expected along with substantially more radioactive fallout. The residents of Rongelap and Utirik Atolls 120km away were subjected to dangerous high energy electromagnetic radiation from the blast and, for years afterwards, they suffered the effects of the high concentration of radioactive chemical elements deposited by the fallout from the bomb. This resulted in high, early mortality rates and was a salutary warning to the international community on the dangers of atmospheric testing. It wasn't until 1963 that the Partial Test Ban Treaty was signed. This prohibits the testing of all nuclear weapons except for those underground. Many countries have not signed the treaty, most notably France, China and North Korea.

In 1996 the Comprehensive Nuclear Test Ban Treaty was prepared which banned all nuclear explosions for both civilian and military purposes. Many nations, including China, North Korea and the United States have not ratified the treaty, which is not yet enforceable. Efforts continue to persuade all countries to sign this treaty and to go one step further by disarming nuclear weapons completely. One of the key promoters is the International Campaign to Abolish Nuclear Weapons, winner of the 2017 Nobel Peace Prize.

No matter where a bomb is detonated, nuclear fallout is an issue, the closer to the detonation site the more concentrated and therefore dangerous the fallout. Potentially dangerous nuclear isotopes can enter the atmosphere, the sea and the food chain. Of course if the missile strays from the target and hits land or water near a populated area, then the consequences would be devastating. Even if the threatened North Korean test impact zone is far from populated areas, there is a danger that launching an armed nuclear missile and detonating it over the Pacific could be regarded as hostile enough to trigger major military responses from South Korea, Japan and of greatest concern, the United States. That could drag China into the conflict leading to a serious confrontation between the two super powers.