NGNP and gas cooled reactor history
Gas Cooled reactor history
As shown in the figure (following page), gas-cooled reactors have a rich history and a promising future. The earliest commercial gas-cooled reactors were primarily developed and used in the United Kingdom (UK) and France and used CO2 as a coolant. Eighteen of these CO2 gas-cooled reactors are still in operation in the UK. Because of its capacity to produce higher outlet temperatures, helium is the coolant of choice for future gas reactors. Peach Bottom Unit 1 and Fort Saint Vrain (FSV) were two helium-cooled demonstration plants built and operated in the U.S using a graphite block fuel configuration. Peach Bottom Unit 1 was a 110 MWt reactor with an outlet temperature of 794°C and was operational from 1967 – 1974. FSV was a 842 MWt reactor with an outlet temperature of 778°C and was operational from 1976 – 1989. There were numerous successes and problems with FSV which provided valuable insight into the design, construction and operation of gas-cooled reactors. The Germans developed pebble-bed gas reactors and demonstrated them with the Arbeitsgemeinschaft Versuch Reaktor and the Thorium High Temperature Reactor. The People’s Republic of China HTGR program is based on the German pebble bed design. The centerpiece of the Chinese program is the 10 MWt test reactor called HTR-10. The Chinese are also pursuing a modular design called HTR-PM which builds upon their operational test reactor experience. In Japan, the High Temperature Test Reactor (HTTR) is the center-piece of their HTGR program. The 30 MWt HTTR is a prismatic block design with outlet temperatures as high as 950°C. The Republic of South Africa had a gas reactor program that was structured to support the deployment of the Pebble Bed Modular Reactor (PBMR). South Africa was evaluating the configuration and size of a PBMR best suited to their national needs with a potential co-generation cycle for electricity production that would have support near term process heat applications in the 200Mwt size for use in their coal-to-liquids industry that supplies over 40 percent of their liquid petroleum needs.
While not all of the gas reactor demonstrations and deployments satisfied every expectation, the operation of the early reactors and the current test reactors have demonstrated the practicality of the pebble bed and prismatic gas-cooled reactor designs. The Next Generation Nuclear Plant (NGNP) Project is aimed at demonstrating improvements to the gas-cooled reactor technology and supporting its commercial viability for industrial applications in the United States.
NGNP Project History
The Next Generation Nuclear Plant Project found its origins in A Technology Roadmap for Generation IV Nuclear Energy Systems, published in December 2002, by the Department’s Nuclear Energy Research Advisory Committee in cooperation with the Generation IV International Forum (GIF). The Technology Roadmap identified the Very-High Temperature Reactor (VHTR) as a system with potential for economical near-term development that is compatible with advanced electricity and hydrogen production, and high-temperature process-heat applications. VHTRs extend the operating temperature range of HTGRs upwards to 950°C. It should be noted that although the operating temperatures envisioned under the NGNP are less than those of the GIF VHTR concept, a great deal of the research and development activities are mutually supportive and therefore the NGNP Project benefits from this international collaboration.
In FY 2003 and 2004, the Department invested in early program planning and limited research and development activities for VHTR concepts. These investments included an independent assessment of the near-term commercialization potential for VHTR technology options that included prismatic and pebble bed designs and a design using salt as a coolant. These development efforts were the beginnings of the Next Generation Nuclear Plant Project.
In 2005, the Energy Policy Act of 2005 (EPAct 2005) (Public Law 109-58) formally authorized the Next Generation Nuclear Plant. Sections 641 through 645 of EPAct 2005 established requirements for research, development, design, construction, and operation of a prototype nuclear plant that would provide electricity and/or hydrogen. Section 644 established the requirement for the NRC to establish the licensing requirements necessary to support the commercialization of this technology. One of the key expectations was for the creation of a public-private partnership between the Department and industry to share in the cost and risks associated with the commercialization of this technology. Section 988 of EPAct 2005 provides the overall formulation and requirements for cost-sharing.
The provisions of the EPAct 2005 establish two distinct phases for the project. Phase 1 is the phase that covers selecting and validating the appropriate technology, carrying out enabling research, development and demonstration activities, determining whether it is appropriate to combine electricity generation and hydrogen production in a single prototype and carrying out initial design activities for a prototype reactor and plant, including development of design methods and safety analytical methods and studies. Phase 2 is the phase that covers development of a final design for the prototype nuclear reactor and plant through a competitive process, application of licenses to construct and operate the prototype nuclear reactor from the NRC, and construction and start up operations for the prototype nuclear reactor and its associated hydrogen or electricity production facilities. Both phases include research and development and licensing activities.
