In the first years after the discovery of radioactivity it became clear that nuclear physics was, by excellence, the science of small quantum systems. Between the fifties and the eighties nuclear physics and elementary particles physics lived their own lives, without much interaction. During this period the basic concepts were defined. Recently, contrary to the specialization law often observed in science, the overlap between nuclear and elementary particle physics has become somewhat blurred.

This Les Houches Summer School was set up with the aim of fighting off the excessive specialization evident in many international meetings, and return to the roots. The twofold challenge of setting up a fruitful exchange between experimentalists and theorists in the first place, and between nuclear and hadronic matter physicists in the second place was successfully met.

The volume presents high quality, up-to-date reviews starting with an account of the birth and first developments of nuclear physics. Further chapters discuss the description of the nuclear structure, the physics of nuclei at very high spin, the existence of super-heavy nuclei as a consequence of shell structure, liquid-gas transition, including both a description and a review of the experimental situation.

Other topics dealt with include the interactions between moderately relativistic heavy ions, the concept of a nucleon dressed by a cloud of pions, the presence of pions in the nucleus, the subnucleonic phenomena in nuclei and quark-gluons deconfinement transition, both theoretical and experimental aspects. Nuclear physics continues to influence many other fields, such as astrophysics, and is also inspired by these same fields. This cross-fertilisation is illustrated by the treatment of neutron stars in one of the final chapters. The last chapter provides an overview of a recent development in which particle and nuclear physicists have cooperated to revitalize an alternative method for nuclear energy production associating high energy production accelerators and sub-critical neutron multiplying assemblies.

This book describes the basic knowledge in nuclear, neutron, and reactor physics necessary for understanding the principle and implementation of accelerator driven subcritical nuclear reactors (ADSRs), also known as hybrid reactors.
Since hybrid reactors may contribute to future nuclear energy production, the book begins with a discussion of the general energy problem. It proceeds by developing the elementary physics of neutron reactors, including the basic nuclear physics involved. The book then presents computational methods, with special emphasis on Monte Carlo methods. It examines the specifics of ADSR, starting from the neutron spallation source to safety features. A thorough discussion is given on the size of hybrid reactors, which follows very different constraints from that of critical reactors. The possibility to optimize the source importance is examined in detail. The discussion of the fuel evolution follows with its relevance to safety and to the waste production and incineration. The conditions for having a constant reactivity over sufficiently long lapse of time are also discussed. The book also evaluates a number of practical designs that have been proposed. Finally, the last chapter deals with the examination of proposed and possible waste transmutation policies and the role which could be played by ADSR in this context. The potential advantage of the Thorium cycle is discussed as well as different scenarios that could be used to implement it.