|Fig. 1: Very High Temperature Reactor. Source: Wikimedia Commons).|
Nuclear energy is an incredibly efficient method of producing and generating electricity that also enables low carbon emissions. Currently, many nuclear power plants use generation III reactors to produce power.  There is much hope for generation IV reactors in terms of sustainability, safety, and price. While Generation III reactors will likely remain popular as the choice technology for new reactors currently being built, Generation IV will be an opportunity to build more sustainable nuclear reactors for the longer term future (by that meaning in the next 20 - 50 years).  The technology is certainly enroute for this timeline, but there are other political, strategic, and economic hurdles that Generation IV prototypes will need to overcome in order to actually become part of the nuclear power infrastructure.  One of the biggest hurdles is the fact that there has been a decrease in funding for Generation IV reactors, especially given the popularity of Generation III reactors.  Though Generation IV shows quite a bit of promise, especially in developing applications outside of current Nuclear Power Plants (NPPs), it is hard to move the current technology past the status quo.  To find a solution to this problem, many large international organizations, such as the GIF, have been working to find synergies with other systems to promote the R&D of Generation IV reactors.  Major areas of R&D for Generation IV reactors have been in sustainability and safety, two key measures that nuclear reactor development is measured against. 
2014 marked a period of important progress in terms of safety design guidelines for Generation IV reactors. There has been an established hierarchy of safety standards, starting with Safety Fundamentals, and moving on to Safety Design Criteria and Guidelines, ending with Technical Codes & Standard.  The safety criteria is also being explored for the variety of different systems that have been prototyped, including VHTR (Very High Temperature Reactor), SFR (Sodium Fast Reactor), SCWR (Super Critical Water Reactor), GFR (Gas Fast Reactor), LFR (Lead Fast Reactor), and MSR (Molten Salt Reactor). [3,4] These six are the main designs being explored, with modifications being made after the Fukushima accident.  The six designs fall under two general categories thermal reactors, and fast reactors.  Main safety designs being explored would allow reactors to avoid pressurized operations, and have automatic reactor shutdowns in the case of emergency.  Many designs also seek to avoid the usage of water to cool the reactor (which would reduce the risks in the situation where water is lost through leaks or heat). 
The main advantages Generation IV seeks to provide is reducing the amount of time the waste remains radioactive for (on the magnitude of ten, reducing from millenias to centuries), improving the energy yield for the nuclear fuel, increasing the variety of fuels that can be used to power the reactor, and allowing for reactors to use already present nuclear waste in its operations.  Many of these goals are encompassed under the umbrella of sustainability, to enable nuclear reactors to become more sustainable and environmentally friendly. 
Generation IV reactors have some very large goals ahead, but they are the ones that we should all be aiming for. Nuclear power has the potential to change the way energy is accessed on this planet, and could provide an alternative that is efficient and sustainable.
© Evelyn Xue. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 "Annual Report 2014," Gen IV International Forum, Nuclear Energy Agency, 2014.
 "A Technology Roadmap for Generation IV Nuclear Energy Systems," U.S. Department of Energy, GIF-002-00, December 2002.
 B. Kallman, "The Very High Temperature Reactor," Physics 241, Stanford University, Winter 2013.
 G. Roberts, "Nuclear Reactor Basics and Designs for the Future," PHysics 241, Winter 2013.
 G. Locatelli, M. Mancini, and N. Todeschini, "Generation IV Nuclear Reactors: Current Status and Future Prospects." Energy Policy 61, 1503 (2013).