21.06.2020

Operation "Needle"

How were measurements of radiation levels and temperature in the reactor

 

From the story of Konstantin Pavlovich Checherov.


- In the month of May, I flew more than once over a destroyed reactor with a device. The evidence was stunned. In the afternoon the heat is under +35, the building structures warmed up, and inside the reactor it shows +24! Not that 1000 degrees, could not find a hundred degrees. It was decided to fly in the morning. When the building has finally cooled down and there will be no thermal interference. But alas, the result remained the same. Walls +14, and in the collapse +24! The performance of the device was checked repeatedly, but the result remained the same.


In early May, the temperature inside the destroyed reactor was still holding and sometimes reached 300 degrees. A month later, with the help of an American heat meter, regular measurements were carried out, which showed +24 degrees.


July 19, 1986, a special operation was carried out under the name "Needle". To measure temperatures and radiation levels in the reactor shaft, it was decided to create a special probe in the form of a long 18 meter pipe inside which all kinds of sensors for measurement were located. A 300-meter-long halyard was attached to the upper end of the pipe; inside it was a cable for connecting sensors to measuring equipment.


In order to lower the Igloo into the reactor shaft, it was decided to use helicopter pilots. Using a helicopter, the rod was lowered into the destroyed reactor, and the other end with the cable was dropped outside the unit. As a result, the cable itself did not fall where it was originally planned. In order to get it, academician Yevgeny Velikhov and Vyacheslav Pisemny went into the corridor from which a view of the destroyed reactor through panoramic windows was opened. It was necessary to act as quickly as possible, since the chamber of gamma rays from the reactor was strong enough. The weighing end of the cable was found outside the corridor window. The writing room broke the glass and picked up the cable with a rod with a sensor from the DP-5V dosimeter and pulled it up.


Using the "Needle" data were obtained on +50 degrees and something about 180 x-rays per hour. Then practically it didn’t fit into everyone’s head that in the reactor shaft, where the molten fuel is located, the numbers should be much higher.


In 1989, when the inspection of the central hall began, it was established that the Igla rod did not enter the reactor shaft, but into the empty northern holding pool. It should be noted that lowering such an element as an iron 18 meter pipe from a helicopter and getting to the right point is an extremely difficult task. Helicopter pilots did not make much mistakes. If they took it 5-6 meters to the west, then they would end up in the reactor.
Then in 1986, everyone thought that the “Needle” hit the reactor shaft. When you look from a helicopter, it is difficult to determine where the rod is sticking out. The exposure pool and reactor shaft are very close. Then radiation measurements were taken in the northern exposure pool vertically and received 35 X-rays per hour at the bottom of the pool, and 70 X-rays per hour at the floor level of the central hall, where the blockage was. But this is 89, therefore, in 86, it could well have been 180 X-rays per hour. So the data obtained using the "Needle" were correct. Only data on the situation in the holding pool, and not in the reactor shaft.