Preliminary Evaluation of a Nuclear Scenario Involving Innovative Gas Cooled Reactors

Abstract

In order to guarantee a sustainable supply of future energy demand without compromising the environment, some actions for a substantial reduction of emissions are nowadays deeply analysed. One of them is the improvement of the nuclear energy use. In this framework, innovative gas-cooled reactors (both thermal and fast) seem to be very attractive from the electricity production point of view and for the potential industrial use along the high temperature processes (e.g., production by steam reforming or I-S process). This work focuses on a preliminary (and conservative) evaluation of possible advantages that a symbiotic cycle (EPR-PBMR-GCFR) could entail, with special regard to the reduction of the HLW inventory and the optimization of the exploitation of the fuel resources. The comparison between the symbiotic cycle chosen and the reference one (once-through scenario, i.e., EPR-SNF directly disposed) shows a reduction of the time needed to reach a fixed reference level from 170000 years to 1550 years (comparable with typical human times and for this reason more acceptable by the public opinion). In addition, this cycle enables to have a more efficient use of resources involved: the total electric energy produced becomes equal to 630 TWh/year (instead of only 530 TWh/year using only EPR) without consuming additional raw materials.

Assessment of the Anticipated Environmental Footprint of Future Nuclear Energy Systems. Evidence of the Beneficial Effect of Extensive Recycling

“…This choice does not reflect the diversity of 4th generation reactors and their associated fuel cycle explored worldwide [5] or in the Generation IV International Forum (GIF) [6] but rather illustrates the benefits of FNR in the French nuclear strategy. Although our paper is based on the French strategy and does not aim at reflecting all the potential future reactors systems, it is important to recall that EPRs can be potentially used also for other innovative fuel cycles [7][8][9].…”

Study of an intrinsically safe infrastructure for training and research on nuclear technologies

“…Looking at the table, Cm 244 is substantially the only isotope that undergoes a significant reduction during irradiation (around 8%): considering the well-known toughness in reducing that isotope inside critical reactors [1][2][3], the obtained results appear worthy of further future investigations.…”

“…a core for which the effective neutron multiplication coefficient k eff is less than unity. The fact that k eff < 1 means that at each fission, the number of neutrons that will in turn produce another fission is less 02004-p. 3 than unity, which implies that there is no self-sustained chain reaction. As a consequence, the reactor can be operated in steady state conditions only if additional neutrons are supplied through an external source.…”

“…The total evaluated reactor power with its systematic error is P tot = 199 kW th , i.e. about 0.4 W th /cm 3 , with a maximum uncertainty of about 15%, depending on the libraries used.…”

“…Different solutions have been proposed and minimization of waste has become an important aspect in the development of innovative nuclear energy systems (see, as examples, [1][2][3][4]). One of the possible strategies for waste minimization implies the so-called double-strata approach [5], in which the second stratum is a transuranic (Pu, MA) transmutation scheme based on dedicated fast reactors and Accelerator-Driven Systems (ADS) 1 .…”