A natural nuclear fission reactor with a power output of 3-to 10 Terawatt at the center of the earth has been proposed as the energy source of the earth’s magnetic field. The proposal can be directly tested by a massive liquid scintillation detector that can detect the signature spectrum of antineutrinos from the geo-reactor as well as the direction of the antineutrino source. Such detectors ar...

The studies summarized in this paper aims to predict the steady state operation of a low-enriched uranium fuel ARGUS type aqueous homogeneous reactor for producing 99Mo meet domestic demand Brazil through coupled multi-physics (Neutronics + Thermal-hydraulics) evaluation. evaluation included aspects related neutronic behavior such as fission induced energy deposition profile, medical isotopes p...

Matrix exponential methods have long been utilized for isotopic depletion in nuclear fuel calculations. In this paper we discuss the development of such addition to species transport liquid fueled molten salt reactors (MSRs). Conventional work with fixed assemblies which fission products and fissile material do not throughout core. Liquid a much different way, allowing primary reactor loop. Bec...

This paper describes a methodology to evaluate the radiological risk of postulated accident scenarios during the decommissioning phase of commercial nuclear power plants. The fuel damage scenarios include those initiated while the reactor is permanently shut down and the spent fuel is initially located in the reactor pressure vessel and successively moved in the spent fuel storage pool. This pa...

Practical application of thermionic space nuclear power systems necessitates the investigation of such systems responses to changes in operation and design parameters as well as load-following characteristics. The principle building block in these systems is the thermionic fuel element (TFE). A Thermionic Transient Analysis Model (TUAM) is developed to simulates transient and steady-state opera...

Challenges of managing long-living spent nuclear fuel wastes are to be technically overcome by a partitioning and transmutation system named as PEACER that is an abbreviation of its design goals: Proliferation-resistant, Environment-friendly, Accident-tolerant, Continuable and Economical Reactor. PEACER has been developed to manage spent nuclear fuels by uniquely combining Pb-Bi cooled critical...

Vaporization of fission products and certain other materials is estimated for the extreme environmental conditions projected for severe reactor accidents. Partial pressures of gaseous species are calculated from thermochemical data or estimates. Mounts of vapor transported material are evaluated from projected gas flows during two phases of a hypothetical accident--( a) core dry out phase and (...

This annex summarizes what decommissioning is, alternative decommissioning strategies, the status of decommissioning projects around the world, and the factors that influence choices among decommissioning strategies. After a nuclear power reactor is turned off for the last time, the initial steps toward decommissioning are not unfamiliar. The fuel is moved to the spent fuel storage pond where i...

The principle drawbacks of any kind of solid nuclear fuel are listed and briefly analysed in the first part of the paper. On the basis of this analysis, the liquid fuel concept and its benefits are introduced and briefly described in the following parts of the paper allowing to develop new reactor systems for nuclear incineration of spent fuel from conventional reactors and a new clean source o...

A fast spectrum accelerator-driven system (ADS) may become a very versatile tool in the nuclear industry and allow a number of new applications. Such a system may serve as a means of transmuting large quantities of actinides and long lived fission products into short lived waste. Other possibilities, include the cross-progeny fuel cycle burning Pu in a thorium matrix and generating 233U which c...