Nuclear Reactors 555 - Safety Systems On Russian Water-Water Energetic Reactors - Part 1 of 2 Parts
Part 1 of 2 Parts
Russia is fully committed to nuclear power for domestic power generation and as a product to export. They have been going around the developing world talking deals with nations trying to expand their economies and to lift their people out of poverty. They will often offer loans to other countries to build Russian reactors for them. They also offer to fuel the reactor, operate the reactor and remove the spent fuel. One concern about such Russian plans is the reality that the Soviet Union and Russia both tried to influence the politics of countries in Eastern Europe by threatening to cut off their gas and/or oil exports to those countries.
Some of the worst nuclear accidents and nuclear pollution in the world occurred in Russia and neighboring countries during the Cold War. The Chernobyl disaster in Ukraine in 1986 had a profound affect on the Russian nuclear industry. They realized that the dangers of poor design and incompetence and have worked ever since to make Russian nuclear reactors extremely safe.
In a nuclear reactor, when the flow of neutrons increases, so do the reactions and the temperature rises along with the amount of steam. Control rods made of a neutron absorbing materials can be inserted into the core to reduce the neutron flow and cool off the reaction and reactor.
In the Fukushima General Electric reactors, the control rods were placed below the core and required electricity to be moved up into the core. When the emergency power failed at Fukushima, the rods could not be inserted, and disaster followed.
First the Soviet Union and then Russia developed a series of pressurized water reactors referred to as Water-Water Energetic Reactors (WWER). Their power output varies from seven hundred megawatts to twelve hundred megawatts and a seventeen hundred-megawatt reactor is under development. Versions of the WWER were installed throughout the countries that made up the Soviet Union. The WWERs were used in, are being used in or are being planned for construction in Armenia, Bangladesh, Belarus, Bulgaria, China, Czech Republic, Egypt, Finland, Germany, Jordan, Hungary, India, Iran, Slovakia, Ukraine, Russia, Turkey and Vietnam.
In the latest version of the WWER, known as the AES-92, as the temperature and the amount of steam in a WWER rises, the steam begins to absorb neutrons and the temperature and steam are reduced. In a WWER, the control rods are positioned above the reactor. If the power fails, the electromagnetic clamps that hold the rods shut off and gravity drags the rods down into the core. The WWER is self-correcting and does not require human intervention to operate stably.
There are additional security measures in Russia WWERs that are dedicated to making the reactors safer. These four safety measures makeup forty percent of the cost of the reactor.
The fuel cells in the reactor are manufactured at one thousand-degree Centrigrade temperatures and are resistant to very high temperatures. There is a zirconium fuel cell matrix that can prevent nuclear fuel from being released into the coolant. There is a two-circuit coolant system (there was only one circuit cooling system in the Fukushima reactors). This would prevent fuel from being dumped outside the containment zone of the reactor.
Please read Part 2