Time scales for fission at finite temperature
نویسندگان
چکیده
The concept of the ”transient effect” is examined in respect of a ”mean first passage time”. It is demonstrated that the time the fissioning system stays inside the barrier is much larger than suggested by the transient time, and that no enhancement of emission of neutrons over that given by Kramers’ rate formula ought to be considered.
منابع مشابه
Cooling history and exhumation of the nepheline syenites, NW Iran: constraints from apatite fission track
Thermal history and apatite fission-track ages were determined for the Kaleybar, Razgah and Bozqush alkaline intrusions which display Eocene-Oligocene stratigraphic age. These subduction-related intrusions are located in the Alborz-Azarbaijan magmatic belt which is characterized by a Paleogene magmatic flare-up associated with extensional/transtensional tectonism. The mean of Uranium content an...
متن کاملAnalytical Analysis of The Dual-phase-lag Heat Transfer Equation in a Finite Slab with Periodic Surface Heat Flux (RESEARCH NOTE)
This work uses the dual-phase-lag (DPL) model of heat conduction to demonstrate the effect of temperature gradient relaxation time on the result of non-Fourier hyperbolic conduction in a finite slab subjected to a periodic thermal disturbance. DPL model combines the wave features of hyperbolic conduction with a diffusion-like feature of the evidence not captured by the hyperbolic case. For the ...
متن کاملComparison of multimesh hp-FEM to interpolation and projection methods for spatial coupling of thermal and neutron diffusion calculations
Multiphysics solution challenges are legion within the field of nuclear reactor design and analysis. One major issue concerns the coupling between heat and neutron flow (neutronics) within the reactor assembly. These phenomena are usually very tightly interdependent, as large amounts of heat are quickly produced with an increase in fission events within the fuel, which raises the temperature th...
متن کاملDissociation, Fragmentation and Fission of Simple Metal Clusters *
Dissociation, fragmentation, and fissioning processes underly physical and chemical phenomena in a variety of finite-size systems, characterized by a wide spectrum of energy scales, nature of interactions, and characteristic spatial and temporal scales. These include nuclear fission [1,2], unimolecular decay and reactions in atoms and molecules [3], and more recently dissociation and fragmentat...
متن کاملMean first passage time for fission potentials having structure
A schematic model of over-damped motion is presented which permits one to calculate the mean first passage time for nuclear fission. Its asymptotic value may exceed considerably the lifetime suggested by Kramers rate formula, which applies only to very special, favorable potentials and temperatures. The additional time obtained in the more general case is seen to allow for a considerable increm...
متن کامل