Thursday, 16 May 2013

Small Modular Reactors: Remaining Challenges

Small modular reactors (SMRs) are the subject of increasing interest in recognition of their potential to offer a cheaper, safer and simpler alternative to the large-scale nuclear power plants currently used. The concept of SMRs is based on small reactors that are assembled from factory-fabricated parts or "modules". Each module represents a portion of the finished plant and, in comparison to current large nuclear power plants, SMRs require much less site work to assemble the components into an operational power plant. 

The interest in SMR's technology arises from the fact that SMRs are not only cheaper to construct, run and maintain but can also be built faster than the conventional large nuclear reactors because of their simple design and modular nature. These features make SMRs very attractive to a wide range countries especially those with limited financial capabilities and small (below 10 GW) electricity grids.

Despite these clear advantages, SMRs must overcome a number of challenges before being accepted as a deployable technology in the near future. The main challenge is an institutional one. Current nuclear regulatory bodies lack the human and technical capacities to licenses SMRs, especially the designs that have no performance history or track record such as  the high temperature gas-cooled reactor concept. In addition, the industry lacks a SMR initial project that would prove the point with regards to cost, flexibility and adaptability claims. Such a project would definitely provide many answers and inspire confidence in SMRs. 

While nuclear waste is considered the main problem of the nuclear industry as a whole. SMRs could add an extra complication by being spread out in remote places, as it has been suggested as one of their potential uses. This will make the management of the waste more difficult. A given amount of highly radioactive nuclear waste is easier to manage from one site rather than multiple.  It should be  noted, however,  that fast SMRs have the potential of being able to recycle the waste to breed new fuel while generating power. This will require more R&D in fast SMRs which are less favourable, so far, than thermal (water) SMRs.  Fast SMRs should be given more funding to demonstrate their superior features particularly with regards to recycling actinides (the long-lived part of the nuclear waste) in the fuel as well as incorporating thorium which could prove to be more sustainable than the current uranium- and plutonium-based fuels. 

Wednesday, 8 May 2013

Sustainable energy: redefinition

In his 1865 book, The Coal Question, William Jevons, a British economist, first raised the issue of finite coal reserves and, therefore, limited energy resources as well as the relation between economic growth and energy consumption. Today, and 150 years after Jevons' book was published, we find ourselves in the same position, questioning the availability of resources but with added environmental and ethical concerns. It is no surprise that the world's energy demand is increasing exponentially given the rapidly growing global economy. According to the World Energy Outlook report prepared by the US Energy Information Administration (EIA), the world marketed energy consumption is expected to grow by about  50% from 2007 to 2035. 

The concept of sustainability has evolved over the last few decades. It has shifted from merely representing the availability, efficient use and security of resources to a more ethical notion that considers environmental impact. Although individual countries may still put energy security at the top of their agenda, they now realise the need for a collective global effort to reduce the emission of greenhouse gases, to tackle the problem of climate change.

The consumption of energy to drive the world's economy is not environmentally harmless. Apart from renewable and nuclear energy, all other energy resources contribute, in one way or another, to climate change and air pollution. The undeniable damaging effects of the use of fossil fuel to generate power on the environment have contributed to a shift towards more environmentally friendly plans, especially in Western economies. If the world's reliance on fossil fuel continues to increase, carbon dioxide emissions due to the use of fossil fuel, which comprised about 57% of the total emissions of greenhouse gases in 2004, will increase, too. On the other hand, and according to the International Panel of Climate Change (IPCC), carbon dioxide emissions should be reduced by 50-85% by 2050 to ensure that the global average temperature does not increase more than two degrees.