Other phenomena such as the hydrogen generation and molten fuel contact to the tube wall might have contributed to the tube rupture. The water hammer force is also estimated to have been large enough to break tubes even using conservative assumptions. The results show that assumptions regarding the preaccidnet fuel burnup and flux distributions are major derterminants of the size and shape of the power pulse, especially due to their influence on effective system void reactivity and on the amount, if any, of positive scram reactivity. Abstract - Data presented in the official U.S.S.R. report to the International Atomic Energy Agency on the Chernobyl Atomic Energy Station accidnet are critically assessed. Special attention is given to the derivation of release fractions from fallout measurements, a procedure demonstrated to involve large elements of uncertainty.
Further comments relate to estimates of plume rise and deposition velocity.
A comparison is made with the predictions of previously published theoretical reactor safety studies. These events can be explained quantitatively without conflict with the report submitted by the U.S.S.R. State Committee to the International Atomic Energy Agency Experts' Meeting in August 1986. The anaysis data were prepared based on plant specifications and its operation history obtained from those published literature and accident reports. It was confirmed from these analyses that the main factors causing the accident were the increased enthalpy at the core entrance caused by the test made at low power level and the increased void fraction due to reduced coolant flow rate, in addition to the nuclear characteristics and performance of the control system peculiar to the Chernobyl Nuclear Power Plant.