Dyatlov Chernobyl Quotes

Continuing the experiment after falling to such a low power level resulted in the reactor becoming unstable enough to explode, and Dyatlov holds all the blame for this one crucial decision.

Either way, even 30MWt is near-as-makes-no-difference a complete shutdown and not even enough energy to power the water pumps. At such a low power, an atomic process of ‘poisoning’ the reactor begins - a release of the isotope xenon135, which absorbs and seriously inhibits the fission reaction - and the test was over before it began. Had this massive drop in power never happened, the test would have proceeded without incident and the RBMK’s dangerous shortcomings may never have come to light. Crucially, however, the man in charge of the test, 55-year-old Deputy-Chief Engineer Anatoly Dyatlov, did not stop.

Bryukhanov and Fomin, as the highest ranking men at the plant, were each sentenced to ten years in prison, Dyatlov received five, Kovalenko and Rogozhkin: three, and Laushkin: two. Bryukhanov and Dyatlov - who wrote a book telling his side of the story some years afterwards, in which he placed the blame almost squarely on the designers - were released from prison early due to poor health brought on by radiation exposure. Chief Engineer Nikolai Fomin was declared insane in 1990 and transferred to a psychiatric hospital. Astonishingly, after he recovered he was allowed to return to work at the Kalinin Nuclear Power Plant near Moscow.

The explosion tore away water pipes used to supply coolant into the bottom of the core, preventing the reactor from being fed with water by the mangled pumps. Unfortunately, the operators did not realise this - or were in denial, given the horrifying consequences a reactor explosion would entail - and their lack of understanding lead them down the wrong course of action which served only to exacerbate the situation and throw lives away. Instead, Deputy-Chief Engineer Dyatlov became convinced the explosions had been caused by hydrogen in the Safety Control System’s emergency water tank, and that the reactor must still be intact. Even though he had no real basis for this explanation - and if he had looked out of a window he would have seen that he was wrong - he acted on this belief for hours after.

At 01:23:04, turbine 8 was disconnected and began to coast down.114 The operators still had no idea what was about to happen and began a calm discussion, remarking that the reactor’s task was complete and they could start to shut it down.115 Exactly what happened next is not 100% clear. Dyatlov claimed afterwards that the test proceeded as normal with no problems and that Akimov pressed the EPS-5 emergency safety button simply to shut down the reactor at the test’s conclusion as planned. Others said there were shouts and that Akimov pressed it after Toptunov saw readings on his control board that indicated a serious problem. Though reactivity increased slightly as the turbine speed dropped, some reports and simulations have concluded that no strange phenomena occurred prior to pressing the button and that all readings, under the circumstances, were normal.

The main circulating pumps began to cavitate and fill with steam, reducing the flow of valuable cooling water and allowing steam voids (pockets of steam where there should be water) to form in the core. A positive void coefficient was occurring: the absence of cooling water causing an exponential power increase. In simple terms, more steam = less water = more power = more heat = more steam. Because 4 of the 8 water pumps were running off the decelerating turbine, less and less water was supplied to the reactor as power increased. Throughout the building, ‘knocks’ were heard from the direction of the main reactor hall. Akimov’s control board indicated that the rods hadn’t moved far before freezing, only 2.5 meters from their raised position. Thinking quickly, he released the clutch on their servomotors to allow the heavy rods to fall into the core under their own weight, but they didn’t move: jammed. “I thought my eyes were coming out of my sockets. There was no way to explain it,” recalled Dyatlov, six years later. “It was clear that this was not a normal accident, but something much more terrible. It was a catastrophe.”118

Akimov, prevailed upon by Dyatlov that the reactor could be saved, tried to start the diesel generators before witnessing his superior send two young trainees - Viktor Proskuryakov and Aleksandr Kudyavtsev - to the reactor hall with instructions to lower the control rods by hand. He sent them to their deaths. Dyatlov spent the rest of his life regretting the moment. “When they ran out into the corridor, I realized it was a stupid thing to do. If the rods had not come down by electricity or gravity, there would be no way of getting them down manually. I rushed after them, but they had disappeared,” he said a few years before his death.130 The trainees made it to the massive reactor hall, having navigated their way past destroyed rooms and elevators, and only remained in the vicinity for a minute - stunned by what they saw - but that was enough. They died a few weeks later. Returning to the Unit 4 control room, tanned deep brown by the massive dose of radiation they had absorbed, the pair reported that the reactor was simply no longer there. Dyatlov refused to believe them, insisting they were mistaken: the reactor was intact, the explosion had come from an oxygen/hydrogen mix in an emergency tank. Water had to be supplied to the core!

Although Dyatlov, Shift Foreman Akimov, and Senior Reactor Control Engineer Toptunov had violated some operating regulations, they were ignorant of the deadly failing of the RBMK-1000 that meant that insertion of the control rods, instead of shutting down the reactor at the end of the test, could initiate a runaway chain reaction. Every one of the investigators behind the report now agreed that the fatal power surge that destroyed the reactor had begun with the entry of the rods into its core. ‘Thus the Chrnobyl accident comes within the standard pattern of most severe accidents in the world. It begins with an accumulation of small breaches of the regulations. … These produce a set of undesirable properties and occurrences that, when taken separately, do not seem to be particularly dangerous, but finally an initiating event occurs that, in this particular case, was the subjective actions of the personnel that allowed the potentially destructive and dangerous qualities of the reactor to be released.’ IAEA experts revealed at last the true magnitude of the technical cover-up surrounding the causes of the disaster: the long history of previous RBMK accidents, the dangerous design of the reactor, its instability, and the way its operators had been misled about its behavior. In dense scientific detail, it described the inherent problems of the positive void coefficient and the fatal consequences of the control rod ‘tip’ effect. (pp. 347-348)