CC CPSU Politburo Session July 3 1986 Working copy Excerpts Shcherbina B E Let me report the main findings As we know on April 26 at the fourth block of the Chernobyl station a thermal explosion of the reactor took place The building of the reactor was destroyed Part of the fuel in the form of radioactive debris and aerosol was expelled from the reactor The explosion was preceded by an uncontrolled acceleration of the reactor The accident was caused by a very crude violation of technological regulations and procedures by the operational staff and in connection with serious flaws in the design of the reactor However these causes are not equivalent The Commission believes that the key causal point of the accident were the mistakes of the operational staff The accident became possible in the first place due to serious problems in the work of the operational staff of the station because of the state of carelessness that was created there All attention was focused on the production of electric power Here as never before mistaken confidence in the absolute safety of the NPS of its use as a standard for the entire industry developed into a dangerous conviction The accident was preceded by a test of the power supply for the block's own energy needs in conditions of a hypothetical maximum accident situation The program for that testing was drafted negligently and was not coordinated as it is supposed to be with the chief designer the main engineer the science adviser and the State Atomic Oversight Agency The director of the station and the deputy chief engineer for science did not participate in the drafting of the program or in conducting the testing itself The system of emergency protection includes an automatic shutdown of the reactor when stop-valves of the turbines are closed This protection which is supposed to shut down the reactor immediately turned out to be switched off The stop-valves were closed at 1 23 04 From the notes we see that the command to stop the reactor was issued 36 seconds later Several seconds later estimated time 1 23 46 the explosion occurred These developments were preceded by other violations of technological regulations which in essence brought the reactor to an emergency situation On April 25 the emergency cooling system was switched off which is categorically prohibited while the reactor is operating The mistakes of the operational staff were aggravated by flaws in the reactor design They were the reason that the process developed into the maximum hypothetical accident the biggest in the history of the nuclear power industry After Gorbachev's critical statement about the lack of party control Slavsky E P Mikhail Sergeyevich I am struck by your portrayal of us communists who work in Ministry of Medium Machine Building as if we were not under control of the party As far as Chernobyl is concerned I assert that we created a hand-made explosion Shasharin was singing here like a Bolshoi Theater performer But he did not say why a completely senseless experiment was conducted at the NPS Who needed that experiment Plus they blocked the emergency protection system A nuclear reaction proceeds in the reactor just the same way as it does in a bomb but in the reactor it is controlled In this case the explosion was thermal but it was caused by a nuclear reaction Monstrously we threw a huge amount of debris into the atmosphere Firefighters died because of a lack of competence Even after the fire in the fourth block was extinguished they were ordered to stay there just in case And now it looks like the Ministry of Medium Machine-Building was making decisions about how to build the reactor on a whim But we did not make this decision on our own Here is the history of the issue the first reactor that we built was the reactor of the RBMK type We have dozens of them They work well Their designer is Academician Dollezhal--an experienced person Our first reactor has been working for 30 years and nothing has happened The same type of reactor is used on our submarines The RBMK is a durable good reactor But what have they done at Chernobyl Let us ask--who was directing the experiment A regional engineer The chief engineer the station director Kulov's representatives1--they were all asleep A regional engineer who had no right to do it was directing the experiment Besides they were testing a program that nobody needs Let's bring together all chief engineers of all stations and ask them-- what were the causes An initiative of a regional engineer has led to a catastrophe--there should have been 15 rods but there were only 5 As far as the emergency protection system is concerned these questions were discussed at a high scientific and technological level under the leadership of Academician President of the USSR Academy of Sciences Aleksandrov If you operate the reactor as prescribed 1 representatives of the state Atomic Oversight Agency everything will be fine There are many smartypants now who in this situation imagine that they know everything and they make judgments about everything Gorbachev M S But we live in a democratic society and people can express their opinions Slavsky E P Mikhail Sergeyevich I read your speeches I agree with them One should consider different opinions but we also have real scientists who are competent in these issues Legasov V A The RBMK reactor falls short of international and domestic requirements on several levels There is no protection system no dosimetry system and there is no external hood Of course it is our fault that we did not monitor this reactor I am personally to blame for this as well Secondly although it does not satisfy some formal requirements one cannot say that it is a bad machine Its concept was designed a quarter of a century ago Naturally then the requirements were different I was in Finland in March of this year There was a convention of scientists from many countries who evaluated all reactors working in the world by their actual functioning It was concluded that the best station was the Lovitsa NPS in Finland which uses our equipment but all the automated systems in it were replaced with western technology Second place was given to a power station in the United States and third place to the Leningrad NPS The weak spot of the RBMK has been known for 15 years A similar accident occurred in the United States back in 1962 But there they had a less powerful reactor The cause was operator error Translated by Svetlana Savranskaya for the National Security Archive This document is from the holdings of The National Security Archive Suite 701 Gelman Library The George Washington University 2130 H Street NW Washington D C 20037 Phone 202 994-7000 Fax 202 994-7005 nsarchiv@gwu edu