Interpolation of nuclear reaction energy distributions

This paper discusses several methods of interpolation of data for tables of energy distributions for particles emitted by nuclear reactions. The methods are also applicable to angular distributions. Our primary interest is in interpolation with respect to the energy of the incident particle. We first examine four interpolation methods currently used in the nuclear data community: direct interpolation, unit-base interpolation, interpolation by averages on equiprobable bins, and interpolation by corresponding energies. Because each of these methods has shortcomings, a modified version of interpolation by corresponding energies is proposed here. We call this new method interpolation by cumulative points.     

Spallation reaction and the probe of nuclear dissipation with excitation energy at scission

We study in the framework of the Langevin model the influence of initial excitation energy （E＊） of Hg compound nuclei （CNs） on the sensitivity of the excitation energy at scission （E~c） to the nuclear friction strength （fl）. It is shown that the sensitivity is enhanced substantially with increasing E＊. Moreover, we find that the significant sensitivity of E＊c to fl at high E＊ is little affected by a marked difference in the neutron-to-proton ratio ofa CN and in its size and fissility. Our findings suggest that, on the experimental side, a measurement of E~c in energetic proton-induced spallation reactions can provide not only a sensitive but also a robust probe of nuclear dissipation in fission of highly excited nuclei. Further development of a suitable approach to spallation reaction is discussed.     

Requirements for nuclear energy in the 21st century nuclear energy as a sustainable energy source

Nuclear energy must compete against other energy technologies in the 21st century. It must be economical and it must be proven that it fulfills the conditions for sutainability. This means that the requirements of — no short term depletion of resources — extremely low emission of noxious or radioactive substances to the environment — extremely low release of radioactivity from a nuclear plant in case of the most severe accidents and — the present very long term problem of high active waste must be transformed into a few hundred years problem through destruction of plutonium, transmutation of the minor actinides and the most important very long lived fission products.     

AMBIDEXTER nuclear energy complex: a practicable approach for rekindling nuclear energy application

Aiming at one of the decisive alternatives for long-term perspectives of the nuclear power, an integral and closed nuclear energy system concept is proposed; namely, the Advanced Molten-salt Break-even Inherently-safe Dual-missioning Experimental and Test Reactor (AMBIDEXTER) nuclear energy complex. This essentially comprises two mutually independent circuits of the radiation/material transport and the heat/energy conversion, centered at the integral reactor assembly, which enables one to utilize maximum benefits of nuclear energy under minimum risks of nuclear radiation. The entire reactor system resides in a thin and large Hastelloy vessel, the internal part of which is divided into a number of equipment compartments with neither connection pipings nor active valves necessary. As the reactor operates at very low FP inventory throughout its designed lifetime and there is no primary heat transport pipings outside the reactor vessel, significant release of radioactive materials due to any equipment failure should be incredible. The nuclear-thermalhydraulic characteristics of the molten ThF₄–²³³UF₄ fuel salt extend the self-sustainability of the AMBIDEXTER fuel cycle to enhance the resource security and safeguard transparency. While maintaining the break-even conversion ratio criterion, a flexible fuel management strategy using a certain choice of denaturants should improve its own proliferation-resistance characteristics. As the core technologies associated with developing the AMBIDEXTER concept are mostly available in commercialized forms at present, investigating the integral performance of the concept should be the prime research topic in ongoing 250 MW_th prototype design studies.     

Challenge of nuclear data for innovative nuclear energy

The article devoted to assessment of present-day demand to nuclear data for transmutation problem, including the discussion of required accuracies, status and perspectives of nuclear data evaluation and development of nuclear models. The effect of nuclear data uncertainties on radiation damage of structural materials is discussed. An analysis of ISTC projects related to nuclear data measurement and evaluation is presented. The recommendations for differential, integral experiments and recommendations on the evaluated data preparation are presented.     

Transport of nuclear heat by means of chemical energy (nuclear long-distance energy)

Nuclear long-distance energy, i.e. the transportation of chemically bound energy, represents a potential application for process heat plants in which the endothermic reaction takes place at the heat source (high temperature reactor) whereas the exothermic back reaction occurs at the region of heat utilization (consumer). Due to the following criteria, i.e. reversibility of the chemical reaction, sufficiently large reaction enthalpy, favourable temperature region for the forward and back reactions, and the available technology, a combination of the methods of endothermic steam reforming of methane and exothermic methanation is chosen. As well as supplying household and industrial consumers with heating, process steam and electrical energy, an interconnected system with synthesis gas consumers (e.g. methanol production and iron ore reduction plants) is possible. It is shown that the amount of reactor heat which is convertible into long-distance energy depends considerably on the helium temperatures in the high temperature reactor and lies between 60 and 73% of the reactor power. Conceivable circuit schemes for the nuclear steam-reforming plants and the methanation plants are described. Finally, it is demonstrated, with the help of a simple model for cost estimations, that the nuclear long-distance energy system can make heating for households available in competition with oil heating and that due to the lower specific transport costs, for distances larger than 50 km it is also more economical than the hot water supply from the thermal power coupling of steam turbine plants using light water reactors (LWRs) or high temperature reactors (HTRs).