and 8 days they have now decayed, leaving the more long-lived 137Cs (with a half-life of 30.07 years) and 90Sr (with a half-life of 28.78 years) as main dangers. In March 2011, an earthquake and tsunami caused damage that led to explosions and partial meltdowns at the Fukushima I Nuclear Power Plant in Japan. Significant release of radioactive material took place following hydrogen explosions at three reactors, as technicians tried to pump in seawater to keep the uranium fuel rods cool, and bled radioactive gas from the reactors in order to make room for the seawater. Concerns about the large-scale release of radioactivity resulted in 20 km exclusion zone being set up around the power plant and people within the 20–30 km zone being advised to stay indoors. On March 24, 2011, Japanese officials announced that "radioactive iodine-131 exceeding safety limits for infants had been detected at 18 water-purification plants in Tokyo and five other prefectures". Also in Japan was the Tokaimura nuclear accidents of 1997 and 1999. The 1997 accident was far less fatal than the 1999 accident. The 1999 nuclear accident was caused by two faulty technicians who, in their desire to speed up the process of converting uranium hexafluoride to enriched uranium dioxide, resulted in a critical mass that resulted in technicians Hisashi Ouchi being dosed with approximately 17 sieverts of radiation and Masato Shinohara to be does with 10 sieverts of radiation, which resulted in their deaths. The two's supervisor, Yutaka Yokokawa, who was sitting in a desk far from the tank where the uranium hexafluoride was being poured into, was dosed with 3 sieverts and survived, but was charged with negligence in October 2000. In 2003, in autopsies performed on six dead children in the polluted area near Chernobyl where they also reported a higher incidence of pancreatic tumors, Bandazhevsky found a concentration of 137-Cs of 40-45 times higher than in their liver, thus demonstrating that pancreatic tissue is a strong accumulator of radioactive cesium. In 2020, Zrielykh reported a high and statistically significant incidence of pancreatic cancer in Ukraine for a period of 10 year, there have been cases of morbidity also in children in 2013 compared with 2003. Other serious radiation accidents include the Kyshtym disaster (estimated 49 to 55 cancer deaths), and the Windscale fire (an estimated 33 cancer deaths). The satellite Transit 5BN-3 accident. The satellite had a SNAP-3 radioisotope thermoelectric