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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.
Rob P. Rechard
Nuclear Technology | Volume 190 | Number 2 | May 2015 | Pages 127-160
Technical Paper | Reactor Safety | doi.org/10.13182/NT14-41
Articles are hosted by Taylor and Francis Online.
This paper, Part II of two companion papers, demonstrates the concepts for evaluating the criticality scenario class after closure of a geologic repository for spent nuclear fuel (SNF) and high-level radioactive waste. As an example, the low-probability rationale used to exclude consideration of criticality in the performance assessment of the potential Yucca Mountain (YM) repository in southern Nevada is summarized. The Yucca Mountain Project (YMP) presented a quantitative rationale that the probability of criticality inside breached waste containers was <10−4 over 104 yr to show that criticality was not necessary to consider. The dominant probability occurred when neutron absorber material was inadvertently left out for a package disposing of SNF from experimental reactors owned by the U.S. Department of Energy. In addition, this paper develops a quantitative estimate of the low probability of criticality outside the package in either the engineered or geologic barrier to complement the qualitative rationale developed by YMP. Because consequence may also be used as the basis of screening, consequences of criticality at the potential YM repository are roughly estimated, based on results from the literature. The consequences are then combined with the low-probability estimates as a complementary cumulative distribution function to place the corresponding estimated consequences in context and, thereby, provide further perspective on excluding the criticality scenario class.