ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
March 2026
Nuclear Technology
February 2026
Fusion Science and Technology
April 2026
Latest News
NRC approves TerraPower construction permit
Today, the Nuclear Regulatory Commission announced that it has approved TerraPower’s construction permit application for Kemmerer Unit 1, the company’s first deployment of Natrium, its flagship sodium fast reactor.
This approval is a significant milestone on three fronts. For TerraPower, it represents another step forward in demonstrating its technology. For the Department of Energy, it reflects progress (despite delays) for the Advanced Reactor Demonstration Program (ARDP). For the NRC, it is the first approval granted to a commercial reactor in nearly a decade—and the first approval of a commercial non–light water reactor in more than 40 years.
David D. Lanning
Nuclear Technology | Volume 88 | Number 2 | November 1989 | Pages 139-156
Technical Paper | NSF Workshop on the Research Needs of the Next Generation Nuclear Power Technology / Fission Reactor | doi.org/10.13182/NT89-A34321
Articles are hosted by Taylor and Francis Online.
The modular high-temperature gas-cooled reactor (MHTGR) is modularized primarily to provide the passive safety that will prevent fuel damage over a wide spectrum of accidents. Specifically, this range of safety includes the simultaneous accidental loss of primary coolant flow, depressurization of the coolant system, and failure to trip control mechanisms. The high-temperature capability of the fuel to retain fission products provides a safe margin over this broad spectrum. The passive safety feature of the MHTGR allows elimination of active safety-related cooling components (e.g., pump and valves). The result is a savings in capital cost and an important simplification of management and operator requirements for surveillance of the reactor system. Safety is also less affected by human error. Other advantages of modularization include cost reduction and quality control by factory fabrication and possibilities for stepwise additions to a power plant to follow load growth. A new approach to licensing has been initiated as part of the MHTGR development. This concept includes a system to bridge between the integrated approach to the MHTGR design requirements and the regulatory licensing process. The projected busbar costs (mills per kilowatthour) are estimated to be competitive with coal-fired plants of the same size when two or more MHTGR modules are utilized. Designs with the passive safety features are discussed. Some incentives and impediments for deployment of the MHTGR are examined. In addition, suggestions for university research related to MHTGR are presented.