On March 11, 2011, three reactors were online when a massive earthquake disrupted their power supply, drowned the auxiliary diesel generators in the basements, and submerged pumps supplying each with 3.79 million litres of cooling water a minute. Within hours, the intensely hot radioactive cores in units 1, 2 and 3 had started to melt while the zirconium metal cladding on the uranium fuel rods reacted with water generating hydrogen which forcefully exploded in buildings of 1, 2, 3 and 4, releasing huge amounts of radioactive elements into the air. And 400 tonnes of highly radioactive water – a total of 245,000 tonnes – has been leaking into the Pacific daily since the accident. Three molten cores, each weighing more than 100 tonnes melted their way through 15 centimetres of steel in the reactor vessels, now rest on concrete floors of the severely cracked containment buildings. Each core contains as much radiation as that released by 1000 Hiroshima-sized bombs with more than 200 different radioactive elements, lasting seconds to millions of years. Each of these deadly radioactive poisons has its own specific pathway in the food chain and the human body. Radioactive elements are tasteless, odourless and invisible. It takes many years for cancers and other radiation-related diseases to manifest – from five to 80 years. Children are 10 to 20 times more radio-sensitive than adults, and foetuses thousands of times more so. Females are more sensitive than males. Radiation is cumulative. There is no safe dose. Each dose adds to the risk of developing cancer.

Radiation of the reproductive organs induces genetic mutations in the sperm and eggs, increasing the incidence of genetic diseases over future generations such as diabetes, cystic fibrosis, haemochromatosis and 6000 others. Sea water beside Fukushima is highly contaminated with tritium, the highest level recorded. Tritium causes birth defects, cancers of various organs including brain and ovaries, testicular atrophy and mental retardation. Tritium concentrates in food and fish and remains radioactive for 120 years . Cesium, a potassium mimicker, concentrates in heart, endocrine organs and muscles where it induces cardiac irregularities, heart attacks, diabetes, hypothyroidism, thyroid cancer and rhabdomyosarcoma, a muscle cancer. Cesium is radioactive for 300 years and concentrates in the food chain. Strontium 90, poisonous for 300 years, is analogous to calcium, concentrating in grass and milk, then in bones, teeth and breast milk where it can cause bone cancer, leukaemia or breast cancer. Plutonium lasts 240,000 years and is one of the most potent carcinogens – a millionth of a gram can cause cancer.

Plutonium resembles iron so it can induce cancers in the lung, liver, bone, testicle and ovary. It crosses the placenta, causing severe birth deformities. Each reactor core contains 150 kilograms of plutonium, and five kilograms is sufficient to make an atomic bomb. So nuclear power plants are essentially timeless bomb factories. Iodine 131, radioactive for 100 days, is a potent carcinogen. Already 44 childhood thyroid cancers are suspected in Fukushima. Thyroid cancer is extremely rare in young children. More than 350,000 children still live in highly radioactive areas. Leukaemia and solid cancers of various organs will increase for the next 70 to 80 years in this generation. About 2 million people in Japan live in highly contaminated areas. Food in the contaminated zone will be radioactive for hundreds of years as it concentrates radiation. So cancer will devastate many future Japanese generations.

Japanese doctors are reporting that they have been ordered not to tell patients that their problems are radiation related. The levels of radiation in buildings 1, 2 and 3 are now so high humans cannot enter or get close to the molten cores. It will be impossible to remove these cores for hundreds of years – if ever. Should one of these buildings collapse during another earthquake, the targeted flow of cooling water to the pools and cores would cease and the cores would become red hot, releasing massive amounts of radiation into the air and water. Fuel in five cooling pools could also ignite. Building 4 is severely damaged. A vulnerable cooling pool situated on the roof contains 250 tonnes of very hot fuel rods which were removed from the reactor just before the earthquake struck. Although the rods and their holding racks are still intact, they are geometrically deformed due to the force of the hydrogen explosion and will be dangerous to remove. A large earthquake disrupting the integrity of the building could cause it to collapse, taking down the pool. Zirconium cladding the rods would burn, releasing the equivalent of 14,000 Hiroshima-sized bombs and 10 times more cesium than Chernobyl, polluting much of Japan and the northern hemisphere.

While atmospheric radiation will largely remain in the north, radioactive water and polluted fish will continue to migrate across the Pacific, affecting Hawaii, North America, South America and, eventually, Australia Dr Helen Caldicott is a paediatrician and the founding president of Physicians for Social Responsibility