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Nuclear Science and Engineering
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Delay, cost increase announced for U.K. nuclear project
Perspex screens and reduced seating capacity in the Hinkley Point canteens help protect the workforce during breaks, EDF Energy said. Photo: EDF Energy
The unfortunate effects of the COVID-19 pandemic on nuclear new-build projects haven’t stopped with Vogtle: EDF Energy this morning reported that the expected startup date for Unit 1 at its Hinkley Point C site is being pushed from late 2025 to June 2026.
In addition, the project’s completion costs are now estimated to be in the range of £22 billion to £23 billion (about $30.2 billion to $31.5 billion), some £500 million (about $686 million) more than the 2019 estimate, EDF said, adding the caveat that these revisions assume an ability to begin a return to normal site conditions by the second quarter of 2021.
D. F. Hollenbach
Nuclear Science and Engineering | Volume 179 | Number 3 | March 2015 | Pages 342-351
Technical Note | dx.doi.org/10.13182/NSE13-46
Articles are hosted by Taylor and Francis Online.
More than 50 years ago it was postulated that a naturally occurring nuclear reactor was possible if it started 2 billion years ago. The subsequent discovery of the natural reactor at Oklo confirmed that it is possible for a nuclear fission reactor to naturally form and cycle on and off over extended periods of time. The hypothesis of a naturally occurring reactor was extended to include the possibility of significant quantities of uranium aggregating inside the molten core of Earth due to gravity during its formation. When sufficient quantities of uranium accumulate, a self-sustaining fission reactor could form, which would fluctuate in power as uranium fissions and fission products are produced. Lighter elements would migrate out of the reactor region, and heavier elements would coalesce due to gravity. In this technical note, SCALE, a state-of-the-art nuclear engineering computer code system developed at Oak Ridge National Laboratory, was used to investigate this hypothesis. The analysis indicates that the overall operational parameters of a postulated nuclear fission reactor located in the inner core of Earth must fall within a relatively narrow band in order to still be operating today. If the overall power level were too low, the reactor would not breed sufficient fissile material, and the average enrichment would drop below the level required to form a self-sustained fast reactor. If the power level were too high, the reactor would have burned itself out well before the present day. The objective of this technical note is to provide calculations that support an existing geo-reactor and the operating parameters that would govern a deep-Earth reactor and allow it to still be operating today, 4.5 billion years after Earth was formed. To help bound the possible power range, a simplified, one-dimensional, homogeneous, deep-Earth reactor having a steady-state fission power is simulated over geologic time. Power levels and start times are varied. The simulations show that if the reactor were still operating today, it would have an overall lifetime average operating fission power of <3 TW. Analyses show that both instantaneous and cumulative 3He/4He ratios are a function of fission power, 235U/238U ratio, total uranium mass, and geo-reactor starting time. The calculated 3He/4He ratios are consistent with those observed in nature.