Chernobyl disaster other undamaged reactors at the power station, with No. 3 continuing to produce electricity up into 2000. The accident motivated safety upgrades on all remaining Soviet-designed reactors in the RBMK (Chernobyl No. 4) family, of which eleven continued to power electric grids . The disaster began during a systems test on 26 April 1986 at reactor 4 of the Chernobyl plant near Pripyat and in proximity to the administrative border with Belarus and the Dnieper River. There was a sudden and unexpected power surge. When operators attempted an emergency shutdown, a much larger spike in power output occurred. This second
Effects of the Chernobyl disaster can cause a physiological increase in the rate of pregnancy anomalies, but unlike the dominant linear-no threshold model of radiation and cancer rate increases, it was known, by select researchers who were familiar with both the prior human exposure data and animal testing, that the "Malformation of organs appears to be a deterministic effect with a threshold dose" below which, no rate increase is observed. This teratology (birth defects) issue was discussed by Frank Castronovo of the Harvard Medical School in 1999, publishing a detailed review of dose reconstructions and the available pregnancy data following the Chernobyl accident, inclusive of