Power for the people

There is a room hidden deep underground in each of the reactor complexes at the Barakah nuclear power plant, that a highly trained group of workers hope they will never need to visit.

This is the last option. When all else has failed, this room is where they can shut down the reactor and prevent a nuclear meltdown and potentially deadly release of radiation.

There is no reason why this should ever happen. Nuclear accidents make headlines – Three Mile Island in 1979, Chernobyl in 1986 and Fukushima in 2011 – but all were preventable and the result of human error. The reality is that there are nearly 500 nuclear power plants in the world, almost all operating without serious incident since the mid-1950s.

Everything at the UAE’s first nuclear power plant has been designed with safety in mind. The site is located more than 300 kilometres from Abu Dhabi city and 70 kilometres from Ruwais, the nearest town.

The site is geologically stable and free of earthquake risk. Although on the coast, the possibility of a tidal wave or tsunami is equally remote (and it is worth noting that Fukushima was caused by a failure to carry out proper risk assessment rather than the wall of water ). The seaside location also provides an inexhaustible supply of water for cooling.

People, though, are what will make Barakah work. All have undergone many months of training, often accompanied by rigorous examinations. Much of this takes place in the Simulator Training Centre, an exact replica of the real control rooms in each reactor building.

A wall of 14 display panels allows every aspect of the plant’s operational status to be seen at a glance. More screens sit in front of the desks reserved for reactor operators and their supervisors, who can diagnose faults with a right click of a mouse that instantly accesses the correct page of the digitised handbooks that would otherwise fill an entire wall.

To the left of the flashing computer display is a smaller series of panels, oddly old fashioned with their dials, knobs and switches. This is an analogue replica of the control system, should the main digital network become inoperable. In a third, smaller room, in a different, secure location, another series of switches has the sole role of shutting the reactor down.

As part of their training, operatives may find themselves suddenly facing a simulated emergency, for example, dealing with broken uranium fuel rods contaminating the water that fills the fuel assembly.

Even though the accident is not real, the process, as one of the instructors admits, “can be a bit stressful. But the more realistic it feels, the more we can anticipate.”

The best view of the Barakah power plant involves riding several floors in a lift and then a brisk climb up several flights of stairs to a door the opens onto the roof of an administrative building.

It is worth the climb, and the blast of July heat and humidity that ends it. Spread out below is the entire site from the turbine rooms to the outlets in the azure sea that fills the horizon. But the view is dominated by a series of enormous domes like an industrialised version of a mosque. Three are complete. The fourth, and farthest from view, is still shrouded in scaffolding.

These are the reactor buildings, the key element in the generation of nuclear power, but also one of the most misunderstood.

For all the complex science that lies behind a nuclear reactor, it produces electricity through a process that would have been familiar to an engineer more than 300 years ago.

Water is heated to produce steam, then released under pressure to drive the blades of turbine, the motion of which produces electricity. All power stations work in this way, whether fueled by coal, gas or oil. To understand the power of this steam, just remove the valve from a heated pressure cooker.

What is different about a nuclear power plant is that the heat that creates the steam is created by nuclear fission rather than fossil fuels. Instead the reactors are powered by uranium, a naturally occurring chemical element, whose unstable nucleus can create a chain reaction that in turn generates heat.

After mining, natural uranium undergoes a number of processes, including conversion into a gas, enrichment and cooling into a powder, before being heated and shaped into pellets.

The enrichment process increases the concentration of the uranium-235 isotope to between three and five percent, the requirement for a nuclear reactor. Nuclear weapons require a uranium-235 concentration of more than 90 percent, so the uranium fuel for power plants cannot be used for this purpose.

The process, of course, is far more complex than that. But the benefits of nuclear power is that it is almost pollution-free. Unlike fossil fuel plants, it does not release any CO2 into the air. On the other hand, it does produce radiation.

The Barakah power plant is designed for all of the benefits while mitigating the risks. It will have four reactors, the first of which is 96 per cent complete. When the final reactor begins operating, planned for 2020, the plant will be capable of generating 5,600 megawatts of electricity. A megawatt is a million watts. A light bulb typically requires no more than 100 watts.

The plant uses pressurised water reactors. Uranium pellets are loading into rods, which are in turn fitted in a group as fuel assemblies (see graphic); 241 in each reactor. Water is pumped around the core under high pressure, heated by the process of nuclear fission.

The heat, or thermal energy, is then transferred to a secondary steam generator, a type of boiler that superheats water so that it acquires the quality of gas. Released into the turbines, it spins the blades of what is essentially a giant dynamo that generates electricity. This then leaves by the rows of pylons surrounding the plant and eventually reaches our homes and businesses. It is as simple as that.

Where it becomes more complicated is what happens next. The fuel in the assemblies is exhausted after around 18 months, depending on demand. Nuclear reactors can produce power night and day without a break, a distinct advantage over conventional fuel plants. And the uranium fuel is environmentally friendly. Unlike fossil fuels it does not release carbon dioxide, a contributor to climate change, into the atmosphere. The C02 savings for Barakah have been calculated at 21 million tonnes a year.

But the fuel at a nuclear power plant does have to be changed. At the end of their useful life, the uranium filled assemblies are removed and replaced with fresh supplies. Disposing of the old fuel is the biggest issue with nuclear power for two reasons. Firstly, because they are radioactive and secondly, because in the wrong hands they can be used as the basis for creating a nuclear weapon, either as part of a so-called “dirty bomb” or recycled to make a conventional atomic warhead.

The UAE has agreed it will neither enrich uranium nor re-process spent fuel. In the first instance, the spent rods will be cooled in steel-lined pools and then moved to dry casks, built of concrete and with another steel lining. Finally, they will be sent overseas for disposal.

These are the issues to come. The cooling process can take up to 10 years, and storage in dry casks can last for 60 years. Nuclear power is not just a commitment for our generation, but for our grandchildren and their grandchildren.