September-October 2017 NPJ

Nuclear Plant Journal, September-October 2017 NuclearPlantJournal.com 25 We are in pre-application. We aim at getting that completed as fast and efficiently as possible. Our investors are strongly pushing to achieve commercialization by 2025. We believe we can indeed achieve that, but obviously, will be curtailed by the practicalities of obtaining a nuclear license. Furthermore, we also have attracted funding through the DOE. Two companies were selected, and we were one of them. DOE has targeted 2030 and we believe we can achieve that target. Personally, I would attempt to achieve the 2025 date. In accordance with company line I would have to say that 2031 is the target date. 9. Describe the design and fabrication plan for Xe-100. The interesting fact is that 100% of the Xe-100 components can be manufactured in the United States. Within the US alone, we have already talked to about 10 suppliers for manufacturing of the Xe-100 RPV. Considering the RPV with forgings, core barrel piping, reflector blocks and associated designs we are indeed addressing a formidable industrial renaissance. We follow a very strict and strong systems engineering approach. The phases of design include the pre- conceptual design phase. After a formal review we continued to the conceptual design phase. In concept design, we have several interim phases which all end in gate reviews. According to that, we have a well-defined risk register process to take care of every risk as we define it along the way and also track the progress of issues resolved and how we go about doing that. As published we have several associated companies. One of them is Burns & McDonnell acting as our engineering procurement construction management (EPCM) company, We also have Teledyne Brown, who will design systems or sub- systems requiring special engineering, such as the fuel handling system, a very specialized system. In South Africa, we have built one-to-one systems like that to gain a better understanding of operation and manufacturing. We will involve them on a mutually agreed basis. 10. Which other organizations are involved in Xe-100? We are in discussion with several organizations, such as Joseph Oat for the RPV and related systems. We would like to consider the potential of achieving economies of scale by number, rather than mass. This would entail for example discussing with them RPV, forgings and core barrels for 10 reactors. They should furnish us with a plan and schedule on how to produce these. Similarly we are talking to companies, such as SGL and GRAFTECH for the graphite supply. We would like to mass produce these plants in two years. This will most probably not materialize for the first ones, but we believe that by the eighth of a kind, we would be able to achieve our two year goal. 11. How your plant will benefit developing countries? I believe this is the opportunity for developing countries to not only get access to electricity, but to build out their own infrastructure, train their own specialists and take control of their own energy future. Currently there are 90 companies listed on the Cement Information System (CIS) by the Department of Industrial Policy & Promotion in India. We have been dealing with one such company that had more than 30 cement plants in India. One Xe-100 reactors would be perfectly suitable to provide the energy for two of these cement factories and supporting/surrounding infrastructure. The supporting infrastructure include the surrounding community, providing electricity in distributed form. 12. Who’s helping you with digitization of the plant? We have three parts to the plant control. The first part is the reactor protection system (RPS). A challenge given to our I&C designers is to design the RPS without any software, just observing meters, and act upon that, i.e. fly-by-wire. The second part will be what we consider to be the investment protection system (IPS). I think that can be digitally done with a hard wire back-up. The third part would comprise the operational plant control system (OPS). In the Xe-100 reactor, because it’s continuously fueled, very little excess reactivity exists in the core. If, say digitally something goes awry and all the control rods were to step out due to a spurious signal, the released reactivity of about 1.5%, is low enough when translated into increased fuel temperature, it would not cause fuel damage. Furthermore, we have designed the moderation ratio, i.e. the atomic number density of carbon to the uranium, such that if reactivity is added into the core because of steam ingress, one would be able to cover that with the reactivity control and shutdown system. The Xe-100 is explicitly designed with this in mind. This leaves one with a very interesting problem because the reactor control and shutdown system (RCSS) traditionally has been viewed to be a safety system. In our case, it technically is not, because failure of the RCSS will not lead to fuel damage or radiological release. We are indeed looking forward to discussing this eventuality with the regulator, but we have proven this fact both theoretically and in several tests. A further backup measure is found when defueling roughly 0.5 m 3 of the fuel from the reactor. This will render the reactor core sub-critical. Contact: Melanie White Lyons, X Energy, 7701 Greenbelt Road, Suite 320, Greenbelt, Maryland 20770; telephone: (301) 363-2839, email: mlyons@x- energy.com.