In April, 1986 in Chernobyl was planned to carry out a stop of the fourth reactor. The stop of the thermal equipment is a business slow, and power engineering specialists from the Chernobyl NPP on it had no time. What happened further, all know.
Instruction
1. The accelerated reactor stop on the Chernobyl NPP led to explosion. What it is necessary to make that the similar option of succession of events was impossible?
2. Water delay in nuclear reactors should not bring in principle to melting of a cover of the fuel elements (TVEL). They melt at a temperature of 1800 wasps, water will already evaporate by then, reaction, will decay and delay will stop. Also power units in which heat is received on fast neutrons are so safe. RBMK developed in the Soviet Union are most dangerous.
3. Control over nuclear reaction is exercised by means of cores from neytronpogloshchayushchy alloys which are shipped in graphite. Lifting cores, reaction is accelerated, lowering – slow down. Now most nuclear power plants works with cores not from graphite, and from reactor structural steel.
4. The essence of a stop of nuclear reactions in the power unit consists in lowering of graphite cores which actively absorb neutrons in an active zone. If to lower cores too quickly, the number of the absorber increases in the reactor, respectively, reaction begins to disperse very intensively though it would seem, there has to be the return. As the result – the reactor can be warmed so that graphite cores are deformed, will jam them, and their most part just will not get to an active zone. Uncontrollable nuclear reaction and thermal explosion becomes result of such fast warming up.
5. Now it is impossible to pull out at the same time from the reactor dangerous quantity of graphite cores on dangerous distance. Blocking join automatically and they cannot be disconnected from the control panel. For repair the cores are taken only on one. For this reason to stop the reactor it is not necessary now.
6. Emergency automatic equipment in nuclear reactors can be switched-off only as a result of the directed explosion now. But in this case cores will be against the stop shipped in the reactor at once. Even if something is also deformed, to pull out the reactor will not be real.
7. Process of a stop of the reactor lasts from two to five years. When the equipment is transferred to a nuclear safe state, it is dismantled and sent for preservation.