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Latest News
Bipartisan Fusion Energy Act pushes for regulatory clarity
Sen. Alex Padilla (D., Calif.) introduced the Fusion Energy Act (S. 4151) last month with a bipartisan group of cosponsors—John Cornyn (R., Texas), Cory Booker (D., N.J.), Todd Young (R., Ind.), and Patty Murray (D., Wash.). The legislation would codify the Nuclear Regulatory Commission’s regulatory authority over commercial fusion energy systems to streamline the creation of clear federal regulations that will support the development of commercial fusion power plants—and would require a report within one year on a study of risk- and performance-based, design-specific licensing frameworks for “mass-manufactured fusion machines.
“Congress must do everything in its power to ensure continued U.S. leadership in developing commercial fusion energy facilities,” said Padilla as he introduced the bill. “The Fusion Energy Act would provide regulatory certainty for investors as the NRC develops and streamlines frameworks for such facilities.”
Nicolas P. Leclaire, Jacques A. Anno, Gérard Courtois, Pascal Dannus, Gilles Poullot, Veronique Rouyer
Nuclear Technology | Volume 144 | Number 3 | December 2003 | Pages 303-323
Technical Paper | Reactor Safety | doi.org/10.13182/NT03-A3447
Articles are hosted by Taylor and Francis Online.
Up to now, criticality safety experts used density laws fitted on experimental data and applied them outside the measurement range. Depending on the case, such an approach could be wrong for nitrate solutions. Seven components are concerned: UO2(NO3)2, U(NO3)4, Pu(NO3)4, Pu(NO3)3, Th(NO3)4, Am(NO3)3, and HNO3. To obviate this problem, a new methodology based on the thermodynamic concept of mixtures of binary electrolytes solutions (one electrolyte + water) at constant water activity, a so-called "isopiestic" solution, has been developed by the Institute de Radioprotection et de Sûreté Nucléaire (IRSN) to calculate the nitrate solutions density. This paper presents its qualification by using criticality experiments. The theory and the implementation are also given.Qualification results of the uranyl and plutonium nitrate solutions show that the new density law (also called the isopiestic law) is in good agreement with the benchmarks. Thus, no bias is put into evidence for the uranium solutions, and a small negative bias equal to 0.2% is found for the plutonium solutions.Moreover, the isopiestic law corrects the observed 1% overestimation of keff due to the empirical IRSN Leroy and Jouan density law for uranium solutions and the observed 3.4% underestimation of keff due to the ARH-600 density law for plutonium solutions.The isopiestic density law has been implemented in CIGALES V2.0, the graphical user interface of the French criticality safety package CRISTAL that calculates the atom densities of nuclides (and writes the input file for CRISTAL computations).
