A review is made of the current status of exp 235 U fission cross section data from thermal to 20 MeV neutron energies. The accuracy achieved is compared with the 1 percent accuracy required of a reaction-cross-section standard throughout this range. The ...

The world's first man-made self-sustaining fission reaction was achieved in 1942. Since then fission

Relativistic mean-field theory allowing for triaxial deformations is applied for a systematic study of fission barriers in the actinide region. Different pairing schemes are studied in detail and it is shown that covariant density functional theory is able to describe fission barriers on a level of accuracy comparable with ...

Different types of nuclear fission reactors and fissionable materials are compared. Special emphasis

Calculations were made of neutron-induced fission cross sections on /sup 238/U and /sup 237/Np to compare with new data available up to 100 MeV. This process also produced fission barrier parameters for neptunium and uranium compound systems required for calculation of p + /sup 238/U fission cross sections. To ...

Photo-fission has been proposed for production of neutron-rich radioactive isotopes because potentially attractive absolute fission yields may be achieved with a modest-cost electron accelerator, and because the relative production of the most neutron-rich isotopes should be substantially enhanced in photo-fission ...

After evaluating the properties of uranium oxide coatings prepared by electrodeposition, painting and physical vapor deposition, the vapor deposition method was selected as being preferable for preparing coatings on aluminum electrodes having a total area of 5 m/sup 2/. The electrodes were used in an experimental fission chamber designed at the Oak Ridge National Laboratory ...

A new facility is constructed for measurements of neutron-induced fission cross sections in the 20-180 MeV energy region versus the np scattering cross section, which is adopted as the primary neutron standard. The advantage of the experiment compared to earlier studies is that the fission-fragment detection and the neutron-flux ...

ESECOM has completed a recent assessment of the competitive potential of magnetic fusion energy (MFE) compared to present and future fission energy sources giving particular emphasis to the interaction of environmental, safety, and economic characteristics. By consistently applying a set of economic and safety models to a set of MFE concepts using a wide ...

The Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM) has assessed magnetic fusion energy's prospects for providing energy with economic, environmental, and safety characteristics that would be attractive compared with other energy sources (mainly fission) available in the year 2015 and beyond. ...

The fission fragments yield for photofission of 238U, induced by bremsstrahlung photons with endpoint energies of 25 and 50MeV was evaluated to estimate the possibility of producing the neutron-rich nuclei. The systematics coming from A.C. Wahl's Zp model 1 for charge distribution of fission fragments were used. Results for xenon and krypton isotopes are ...

A review is made of the current status of /sup 235/U fission cross section data from thermal to 20 MeV neutron energies. The accuracy achieved is compared with the 1 percent accuracy required of a reaction-cross-section standard throughout this range. The energy ranges from thermal to 10 keV, 10 keV to 0.8 MeV and 0.8 to 20 MeV are ...

A comparison of the direct capital costs of recent light-water-reactor fission plants and recent magnetic fusion designs indicates that cost reductions by innovation in both the fusion reactor and the fusion balance of the plant (nonreactor part) will be required for fusion direct costs to become competitive. Both future fusion and future fission designs ...

General properties of nuclear fission are reviewed and related to our present knowledge of fission theory. For this purpose the basic reasons for the shape of the fission barriers are discussed and their consequences compared with experimental results on barrier shapes and structures. Special emphasis is ...

The cross section for the fission of uranium by highenergy protons was studied by exposing thick--layered photographic plates with uranium in the emulsion to tabulated. An analysis was made of the light charged particles found in the fission of uranium nuclei by highenergy protons. The data which characterize uranium fission ...

Fission process is considered as a multi-dimensional Brownian motion. The Fokker-Planck equation is solved and the fission probability in the steady state approximation is calculated. The results are compared with Bohr--Wheeler theory. A numerical calculation for the fission of /sup 236/U shows the capability of ...

The fission distribution of fission of thorium with alpha particle of average energy 37.5 Mev has been measured by the chemical method. The distribution found shows that the characteristic dip in the fission yield mass spectrum has been raised to within a factor of two of the peaks compared to a factor of 600 in ...

In recent multi-parameter studies of spontaneous and thermal neutron induced fission, 252Cf(sf) and 235U(nth,f) respectively, the energies and emission angles of fission fragments and light charged particles were measured. Fragments were detected by an energy and angle sensitive twin ionization chamber while the light charged particles were identified by a ...

Rates of atom displacement and helium injection in materials exposed to $sup 252$Cf fission fragments and alpha particles were calculated to establish the potential for use of $sup 252$Cf sources for radiation damage studies. Maximum displacement rates of about 10$sup -6$ dpa/sec at the surface of typical targets exposed to a $sup 252$Cf fission ...

Four representations of the prompt neutron spectrum for the spontaneous fission of /sup 252/Cf are compared with recent differential and integral measurements.

Fission reactors can be used to conduct some of the fusion nuclear engineering tests identified in the FINESSE study. To further define the advantages and disadvantages of fission testing, the technical and programmatic constraints on this type of testing are discussed here. This paper presents and discusses eight key issues affecting ...

The projected cost of electricity (COE) for fusion is compared with that from current and advanced nuclear fission and coal-fired plants. Fusion cost models were adjusted for consistency with advanced fission plants and the calculational methodology and c...

Recent measurements of neutron emission in coincidence with fission fragments indicate a strong enhancement of the neutron multiplicity preceding fission compared with statistical model calculations. This enhancement has enabled the determination of the r...

S>The average power emitted as gamma or beta radiation from U/sup 235/ thermal fission products is calculated as a function of time after fission. Previous work on the subject is surveyed and compared with the present results. (W.D.M.)

It is shown that the fission effect which occurs when thorium is irradiated with slow neutrons is in fact due to fission of Th/sup 232/ by thermal neutrons. The fission cross section is (0.06 plus or minus 0.02) mb. The results obtained are compared with available experimental data relating to ...

The dependence of the driving potential on the orientation of fragments at scission is investigated for the case of cold fission of 252Cf. It is shown that in the case of cold fission the fragments exclusively emerge at scission in the pole-pole configuration. However, quantum fluctuations enable small deviations from this configuration during the ...

For the reactor neutron induced fission of exp 241 Am the fission yields for a total of 35 masses were determined as against exp 235 U fission yields and compared with available data. The shape of the mass distribution curve was well defined by the measur...

The ratio of the yield of fission fragments emitted at angles of 135 and 90 deg during fission of gold nuclei induced by carbon and oxygen ions and also of the products of fission of U/sup 238/ induced by carbon ions was measured. The ranges of the fission products were also measured. The experimental ...

The purpose of this work is to establish the existence of naturally occurring celestial neutrino-driven nucleon fission chain reaction reactors as the first step in the development of controlled nucleon fission reactors on Earth. Celestial nucleon fission reactors provide functioning models that serve as starting points for reactor ...

Recent energy-averaged data (fission, total cross section, scattering and anti nu/sub p/) describing the interaction of fast neutrons with /sup 239/Pu are discussed, with emphasis on neutron energies higher than the inelastic scattering threshold. The linkage between such experimental data and new theoretical calculations is described in context of their influence on a new ...

Recent advancements in laser wakefield accelerators have resulted in the generation of low divergence, hundred MeV, quasimonoenergetic electron beams. The bremsstrahlung produced by these highly energetic electrons in heavy converters includes a large number of MeV {gamma} rays that have been utilized to induce photofission in natural uranium. Analysis of the measured delayed {gamma} emission ...

The double kinetic energy measurement of fission fragments with a double-sided Frisch grid ionization chamber allows a careful determination of the emission angle, which is essential in order to apply appropriate energy-loss corrections. We present a drift-time method, which uses the time that free electrons need to drift from the location of their creation, e.g. by a ...

A gas core fission reactor that utilizes americium in place of uranium is examined for potential utilization as a nuclear rocket for space propulsion. The isomer [sup 242m]Am with a half life of 141 years is obtained from an (n, [gamma]) capture reaction with [sup 241]Am, and has the highest known thermal fission cross section. We consider a 7500 MW ...

Experimental results are presented to demonstrate the feasibility of the subthreshold diagnostics of active media for direct nuclear pumped lasers. The diagnostic approach proposed here is sufficiently universal and may be used for the study of both gas and condensed active media when pumped by nuclear reaction products of any kind. The neutron active materials can be both homogeneous and ...

Synthetic analogues of poor-silicated natural apatites have been doped with uranium. These minerals have been irradiated with a thermal neutron dose in the aim to induce the 235U fission and to obtain a fission track population. Thermal annealing experiments have been performed on the fission track population and allow us to ...

We present a model which allows for the calculation of fragment excitation and kinetic energy in nuclear fission. The model assumes that fission products are excited independently according to an exponential distribution function, which depends on the Q-value of the reaction and the level density parameter in the single fragment. We develop the model ...

The Laser Inertial Fusion-based Energy (LIFE) project at LLNL includes development of hybrid fusion-fission systems for energy generation. These hybrid LIFE engines use high-energy neutrons from laser-based inertial confinement fusion to drive a subcritical blanket of fission fuel that surrounds the fusion chamber. The fission blanket ...

The Time Projection Chamber (TPC), being constructed by the NIFFTE (Neutron Induced Fission Fragment Tracking Experiment) collaboration will be used for high-precision fission cross-section measurements. These measurements will aid in the design of future generations of nuclear power plants. The track reconstruction effort in the NIFFTE experiment consists ...

The use of the fission particles from a 252Cf source in the study of single event effects and latch-up in CMOS memories was studied. Heavy ions from the ALICE cyclotron for cosmic ray simulation were compared with those from the Californium-252 Assessment of Single Event Effects (CASE). The calculated and measured LET distributions obtained for the ...

Probably the single largest advantage of the inertial route to fusion energy (IFE) is the perception that its power plant embodiments could achieve acceptable capacity factors. This is a result of its relative simplicity, the decoupling of the driver and reactor chamber, and the potential to employ thick liquid walls. We examine these issues in terms of the complexity, ...

Reference 1-GWe DT reactors (tokamak TR-1, spherical tokamak ST-1 and helical HR-1 reactors) are designed using physics, engineering and cost (PEC) code, and their plasma behaviours with internal transport barrier operations are analysed using toroidal transport analysis linkage (TOTAL) code, which clarifies the requirement of deep penetration of pellet fuelling to realize steady-state advanced ...

The properties of the heaviest isotopes are discussed using recent results on alpha -energies, halflives, and branchings between the different decay modes. From the data on alpha - and spontaneous fission halflives and absolute masses, fission barriers an...

Fission has been considered for in-space propulsion since the 1940s. Nuclear Thermal Propulsion (NTP) systems underwent extensive development from 1955-1973, completing 20 full power ground tests and achieving specific impulses nearly twice that of the be...

Using a Fokker-Planck equation, we consider induced nuclear fission for large values of the friction constant. Then, the equation simplifies to the Smoluchowski equation which we solve using a method of van Kampen. We find that the fission rate obeys a scaling law. From our numerical results and those obtained previously, we estimate the transient time tau ...

Using a Fokker-Planck equation, we consider induced nuclear fission for large values of the friction constant. Then, the equation simplifies to the Smoluchowski equation which we solve using a method of van Kampen. We find that the fission rate obeys a scaling law. From our numerical results and those obtained previously, we estimate the transient time ? ...

Average recoil ranges were measured for five fission products formed by 23 Mev deuteron reactions with uranium-238. The ranges of products from near symmetric fission (cadmium-115 and silver-111) are longer than for neutron fission of uranium-235, while the ranges of asymmetric products (iodine-131, barium-140, and ...

Fission neutron spectra from neutron induced fission in 235U and 239Pu for energies below that of the neutron inducing fission have been measured. The spectra were obtained for 1.5 MeV and 2.5 MeV incident neutrons. Previous accelerator-based fission neutron spectra measurements have been seriously complicated by ...

We compare the properties of fission induced by protons and pions. Three different methodologies are used to make this comparison. First, it is shown that pion-induced fission cross sections are not much different in magnitude from proton-induced fission cross sections at the same beam kinetic energy. Secondly, ...

Binary fission induced by 140 MeV ? particles has been measured for Agnat, La139, Ho165, and Au197 targets. The measured quantities are the total kinetic energies, fragment masses, and fission cross sections. The results are compared with other data and systematics. A minimum of the fission probability in the ...

Fission properties of the Barcelona�Catania�Paris (BCP) energy density functional are explored by performing constrained mean field Hartree-Fock-Bogoliubov (HFB) calculations along the fission path. These calculations provide us with the quantities required to estimate the spontaneous fission half lives and fragment mass ...

Nuclear fission barriers, mass parameters and spontaneous fission half lives of fermium isotopes calculated in a framework of the Skyrme Hartree-Fock-Bogoliubov model with the SkM* force are discussed. Zero-point energy corrections in the ground state are determined for each nucleus using the Gaussian overlap approximation of the generator coordinate ...

A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to ...

Calculations are made of the fission barriers of pre-actinide nuclei with 73< or =Z< or =85 in the droplet model. The results are compared with the fission barriers obtained in the liquid-drop model and with the experimental data. Use of the droplet model permits rather good description both of the dependence of the macroscopic ...

Mass yields for A = 89 to 140 were measured for U/sup 238/ fissioned by 14.5-Mev neutrons. Comparison is made between the experimental results and those of Thode and Kuroda for spontaneous fission of U/sup 238/. Methods of calculating fission yields are discussed and their results compared with ...

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of ...

A new experimental technique has been developed for the spectroscopic investigation of the neutron-rich products of 252Cf(SF). The charged-particle detector CHICO was coupled to the Ge-detector array GAMMASPHERE and a thin fission source was used allowing the collection of high-statistics, high-fold ?-ray data in kinematic coincidence with the recoiling ...

The Accelerator Transmutation of Waste (ATW) concept has been proposed as a transuranics (TRU) (and long-lived fission product) incinerator for processing the 87,000 metric tonnes of Light Water Reactor used fuel which will have been generated by the time the currently deployed fleet of commercial reactors in the US reach the end of their licensed lifetime. The ATW is proposed ...

Soon after the discovery of fission, Meitner, Bretscher and Cook found differences in the decay of various chemical fractions separated from uranium irradiated with slow neutrons and thorium irradiated with fast neutrons respectively and suggested that a difference existed in the distribution of fission products in the two cases. In 1940, Turner suggested ...

The values of angular anisotropy of fragments in binary and ternary fission of 235U induced by 3 MeV neutrons have been determined with two independent methods. In the first method fission fragments and long range alpha particles were detected with a gridded ionization chamber and a CSI crystal respectively and in the second method semi-conductor detectors ...

This review deals with new trends in nuclear reactors physics. It opens by an easily understood introduction to nuclear fission energy physics, starting with some history, including the achievements of the Kharkov nuclear physics school. Attention has been given to the development of fission theory, the Strutinsky theory, and the ...

The resonance parameters and thermal cross sections of /sup 235/ /sup 238/U and /sup 239/ /sup 240/ /sup 241/ /sup 242/Pu are reevaluated by considering the measurements carried out since 1973. Capture, scattering, fission cross sections as well as resonance integrals are calculated from the parameters and are compared with experimental values with the ...

Although the multiple fission process is important at high neutron energies, most of the evaluations available today do not include these individual fission cross sections or their associated fission spectra. The representations used in the Los Alamos and Livermore libraries are described and calculations compared ...

For isotopically separated secondary beams of 233U delivered by the SIS-FRS facility at the GSI, fission-in-flight induced by electromagnetic excitations in a lead target and by nuclear interactions in a plastic target at beam energies of about 420 . A MeV was observed. The nuclear-charge yields and the total kinetic energies released during the fission ...

Results on light-actinide fission fragments Kr and Xe yields calculated within the framework of a new statistical approach are presented. The proposed statistical method is derived from the equilibrium condition of the ensemble of all possible fission fragments. Using 237Np isotope as an example, we investigate the influence of excitation energy (nuclear ...

A measurement of the angular distributions and yields of fission fragments in the photofission of 234U has been performed between 5.2 and 6.4 MeV. As ?-source, the bremsstrahlung from a microtron was used. For the detection of the fission fragments, solid-state track detectors were used. The present data for 234U have been analysed together with earlier ...

Using the rank annihilation method, recurrence forrmulas for calculating the level matrix elements are given. A multilevel expression of the neutron fission cross section is obtained. The iteration procedure depends on the number of the open fission channels. The /sup 235/U fission cross section for neutron energies less ...

The yields of 27 mass chains in the fission of $sup 235$U and the ratio of fast-neutron to thermal-neutron fission yields of 21 mass chains in the fission of $sup 239$Pu induced by fast neutrons (median energy approximately 180 keV) have been measured in the reactor PROTEUS. The yields were obtained by a comparison method ...

Fission fragment angular distributions have been measured for a Be9 + Th232 system at four different beam energies around the Coulomb barrier. The experimental results on fission fragment anisotropies have been compared with predictions of the standard statistical saddle-point model (SSPM) and the preequilibrium ...

There is a need to develop alternate energy sources in the coming century because fossil fuels will become depleted and their use may lead to global climate change. Inertial fusion can become such an energy source, but significant progress must be made before its promise is realized. The high-density approach to inertial fusion suggested by Nuckolls et al. leads reaction chambers compatible with ...

There is a need to develop alternate energy sources in the coming century because fossil fuels will become depleted and their use may lead to global climate change. Inertial fusion can become such an energy source, but significant progress must be made before its promise is realized. The high-density approach to inertial fusion suggested by Nuckolls, et al., leads to reactors compatible with ...

In this seminal paper, Niels Bohr and John Wheeler give an account of nuclear fission based on the liquid drop model of atomic nuclei. Six months prior to the publication of this paper, Hahn and Strassmann had discovered that neutron bombardment of uranium results in the production of elements of much smaller atomic weight. Meitnerand Frisch gave the name ...

Prompt fission neutrons continue to be examined as a signature for detecting the presence of fissionable material. This technique exploits the neutron energy limitations inherent with photonuclear emissions from non-fissionable material, allowing prompt fission neutrons to be identified and engaged for detecting ...

Three tropics have been considered in the refinement and improvement of our original calculations of prompt fission neutron spectra. These are an improved calculation of the prompt fission neutron spectrum N(E) from the spontaneous fission of /sup 252/Cf, a complete calculation of the prompt fission neutron ...

The 239Pu(117Sn, 118Sn)238Pu reaction at a beam energy of 630 MeV has been used to attempt populating the 0.5 ns fission isomer in 238Pu. The measured cross section for prompt fission of 238Pu populated by neutron transfer is (6+/-2) mb while the cross section for prompt fission of 239Pu excited by inelastic scattering is (1.7+/-1.0) ...

Nucleon-induced fission cross sections determined from a statistical preequilibrium model are used in conjunction with a new scission-point model of fission fragment mass, charge and excitation energy distributions to produce evaporation model calculations of particle and gamma spectra and multiplicities from fission. Comparisons are ...

The fission distribution of thorium with alpha particles of average energy 37.5 MeV was measured by the chemical isolation method. The distribution found shows that the characteristic dip in the fission-yield mass-spectrum has been raised to within a factor of two of the peaks, compared to a factor of 600 in slow neutron ...

The cross sections of {sup 209}Bi nuclear fission induced by secondary beams of {sup 6}He and {sup 4}He are measured under identical conditions. The experimental data are in good agreement with earlier results on the fission cross section of the {sup 4}He + {sup 209}Bi reaction. The measured values of the cross section of {sup 209}Bi ...

Fission excitation functions have been measured for a chain of neighboring compound nuclei from {sup 207}Po to {sup 212}Po. We present a new analysis which provides a determination of the fission barriers and ground state shell effects with nearly spectroscopic accuracy. The accuracy achieved in this analysis may lead to a future ...

In recent years, the microscopic method has been applied to the notoriously difficult problem of nuclear fission with unprecedented success. In this paper, we discuss some of the achievements and promise of the microscopic method, as embodied in the Hartree-Fock method using the Gogny finite-range effective interaction, and beyond-mean-field extensions to ...

Recent advances in the modeling of the nuclear fission process for data evaluation purposes are reviewed. In particular, it is stressed that a more comprehensive approach to fission data is needed if predictive capability is to be achieved. The link between pre- and post-scission data is clarified, and a path forward to evaluate those ...

A new type of decay intermediate between fission and ..cap alpha.. decay is predicted in heavy and superheavy nuclei. Two limiting approaches are presented in which this decay is treated as fission with maximal asymmetry of the fragment masses or as emission of a heavy cluster. It is shown that, if strongly mass-asymmetric two-body fragmentation is treated ...

A measurement of the thermal-neutron fission cross section of Pu/sup 240/ is described. The value obtained, -0.8 plus or minus 0.7 barn, is compared with other measurements. (auth)

The main objective of this study is to investigate whether the amount of long-lived alpha-emitters, fission products and their corresponding hazard in the nuclear waste in the AIROX process recycling scheme is less compared to that in the normally used fu...

The calculated radioactive waste inventories of the Turkey Point pressurized water fission reactor (PWR) and the Starfire conceptual fusion tokamak are compared as a function of time from initial start-up to 10,000 years after decommissioning. Only materi...

Regardless of advances in the theory of fission, the description of mass fragment yields is at a comparatively low level, which in particular manifests itself in the design mass dispersions being essentially less than those observed for neutron induced fi...

A simple approach to the dynamic description of the fission process is proposed. Nuclear viscosity is introduced to link the particle excitation to the classical energy dissipation in a fluid model. The mass-asymmetry ratio is then derived for different nuclear temperatures and compared with experiment. (auth)

In these lectures we present the liquid drop model of fission and compare some of its prediction with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. We then d...

Level schemes of 24 fission product nuclides are compared between JAERI and Petten data collections. When the assignments of spin and parity are different, the reasons for JAERI's are described. In typical cases are the cross section of inelastic scatteri...

A new concept of gettering Ag-110 m and Cs-134 137 in the primary circuit of a High Temperature Reactor (HTR) is presented. It is based upon the known fact that the vapor pressure of metallic fission products in solid or liquid solutions is lower compared...

The self-consistent Hartree-Fock+BCS and Hartree-Fock-Bogoliubov methods are compared at large nuclear deformations. The calculations are carried out for the fission pathway and quadrupole mass parameter of ^{252}Fm.

These proceedings of a specialists' meeting on data for decay heat predictions are based on fission products yields, on delayed neutrons and on comparative evaluations on evaluated and experimental data for thermal and fast fission. Fourteen conferences w...

The behavior of nielsbohrium and niobium--bromine compounds was compared using the frontal thermochromatography technique. The nielsbohrium spontaneous fission isotope was produced by bombarding an americium-243 target with neon-22 ions. The niobium-90 is...

A multigroup theory developed in connection with an investigation of inelastic scattering of fission neutrons was adapted for use in calculations of fast effect in solid iael rods. Theoretical values of both EPSILON and sigma were calculated on this basis and compared with experimental values determined at Hanford and Argorne. (auth)

This report compares the activity and disintegration energy of fission products from metal under two conditions of exposure: 200 Megawatt-days integrated exposure over a period of 180 days, and 400 Megawatt-days integrated exposure over a period of 360 days. (JL)

The adequacy of using smoothly joined parabolic segments to parametrize the multihumped fission barriers has been tested by examining its simultaneous consistency with the three relevant fission observables, namely, the near-barrier fission cross sections, isomeric half-lives, and the ground-state spontaneous ...

The neutron-induced fission cross section for /sup 242m/Am(152y) was measured at the Livermore 100-MeV electron linac in the neutron energy range of 0.01 eV to 20 MeV. Fission fragments were detected using a hemispherical fission chamber. The neutron flux was measured below 10 keV using lithium glass scintillators. Above 10 keV, the ...

This paper presents a preliminary study on neutron physics characteristics of a light water cooled fission blanket for a new type subcritical fusion�fission hybrid reactor aiming at electric power generation with low technical limits of fission fuel. The major objective is to study the fission fuel cycling ...

Recently measured energy dependences of fission cross sections of lead isotopes 204,206-208Pb at incident nucleon energies up to 180 MeV were analyzed. Regularities were established of the fission cross-section variation with the mass number of isotopes pointing to incomplete dumping of shell effects even at nucleon energies 150-180 MeV. The ...

The world's first man-made self-sustaining fission reaction was achieved in 1942. Since then fission has been used to propel submarines, generate tremendous amounts of electricity, produce medical isotopes, and provide numerous other benefits to society. Fission systems operate independently of solar proximity or ...

In order to achieve the high exhaust gas temperatures, which are desirable if the full potential of nuclear fission as an energy source for rocket propulsion is to be realized, it seems essential that the fissionable material be maintained in a gaseous mixture with the propellant. It is then necessary to separate the ...

I define in detail the model used to sample the number of prompt neutrons emitted in fission; this description is based on publications defining the model [1] as well as publications comparing the model to experimental measurements [2]. The model described in these publications is exactly what the TART [3] Monte Carlo transport code uses. Based on ...

Based on stated assumptions. the ratio of potential external energy releases from fission products in local fall-out compared to the Co/sup 60/ that may be produced can vary from a factor of 40. based on an exposure period from 1 hr to 1 month after a detonation. to 0.17 based on an exposure period from the twenty-fourth hour to 35 years. It is ...

Conditioned taste aversion was used to evaluate the behavioral toxicity of exposure to high-energy iron particles (56Fe, 600 MeV/amu) in comparison to that of gamma photons (60 Co), high-energy electrons, or fission neutrons. Exposure to high-energy iron particles (5-500 cGy) produced a dose-dependent taste aversion with a maximal effect achieved with a ...

Conditioned taste aversion was used to evaluate the behavioral toxicity of exposure to high-energy iron particles ({sup 56}Fe, 600 MeV/amu) in comparison to that of gamma photons ({sup 60}Co), high-energy electrons, or fission neutrons. Exposure to high-energy iron particles (5-500 cGy) produced a dose-dependent taste aversion with a maximal effect ...

Severe accident studies for the Savannah River production reactors indicate that if coherent fuel melting and relocation occur in the absence of target melting, in-vessel recriticality may be achieved. In this paper, fuel-melt/target interaction potential is assessed where fission gas-induced fuel foaming and melt attack on target material are evaluated ...

Severe accident studies for the Savannah River production reactors indicate that if coherent fuel melting and relocation occur in the absence of target melting, in-vessel recriticality may be achieved. In this paper, fuel-melt/target interaction potential is assessed, where fission gas-induced fuel foaming and melt attach on target material are evaluated ...

Direct detection of fast neutrons using organic scintillators is one alternative to moderated thermal neutron detectors deployed to detect fission neutrons�a relevant question in light of dwindling 3He supplies. Recent developments in materials science have demonstrated the capability to grow larger crystals in reasonable times. In light of these developments, this study ...

Safety must be ensured during all phases of space fission system design, development, fabrication, launch, operation, and shutdown. One potential space fission system application is fission electric propulsion (FEP), in which fission energy is converted into electricity and used to power high efficiency ...

Fission neutron spectra from neutron induced fission in 235U and 239Pu for energies below that of the neutron inducing fission have been measured. The spectra were obtained for 1.5 MeV and 2.5 MeV incident neutrons. Previous accelerator-based fission neutron spectra measurements have been seriously complicated by ...

A methodology is developed for determining boundaries of spectral zones for pebble bed reactors. A spectral zone is defined as a region made up of a number of nodes whose characteristics are collectively similar and that are assigned the same few-group diffusion constants. The spectral zones are selected in such a manner that the difference (error) between the reference transport solution and the ...

The attractiveness of magnetic fusion as a commercial energy source will depend on its performance, relative to other energy technologies available in the same time frame, with respect to economics, environment, and safety. Although a variety of past and ongoing reviews of fusion's prospects touch different aspects of this issue, the Office of Fusion Energy (OFE) of the US Dept. of Energy ...

The masses of neutron-rich {sup 106-112}Tc, {sup 106-115}Ru, {sup 108-118}Rh, and {sup 112-120}Pd produced in proton-induced fission of uranium were determined using the JYFLTRAP double Penning trap setup. The measured isotopic chains include a number of previously unmeasured nuclei. Typical precisions on the order of 10 keV or better were achieved, ...

The neutron cross sections of 19 selected high-priority nuclei were evaluated in the fast energy region. The calculation was compared with the CSISRS experimental data and the ENDF files. Evaluation procedures included an optical-model parameter search, followed by complete nuclear reaction model calculations with parameters validated against experimental data. A spherical and ...

The neutron cross sections of 19 selected high-priority nuclei were evaluated in the fast energy region. The calculation was compared with the CSISRS experimental data and the ENDF files. Evaluation procedures included an optical-model parameter search, followed by complete nuclear reaction model calculations with parameters validated against experimental data. A spherical and ...

The extraction of uranium(VI) by two amine oxides, 4-(5-nonyl)pyridine oxide and trioctylamine oxide has been studied. The extraction behavior of these two N-oxides is compared. The dependence of extraction on the type of amine oxide and acid, nature of organic diluent, and amine oxide concentration has been investigated. The influence of the concentration of the ...

The LASREF facility is located in the beam stop area at LAMPF. The neutron spectrum is fission-like with the addition of a 3% to 5% component with E > 20 MeV. The present study evaluates the limits on geometry and material selection that will maximize the neutron flux. MCNP and LAHET were used to predict the neutron flux and energy spectrum for a variety of geometries. The ...

The Monte Carlo MVP code system was adopted for the Reaktor TRIGA PUSAPTI (RTP) core calculation. The code was developed by a group of researcher of Japan Atomic Energy Agency (JAEA) first in 1994. MVP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation and able to estimate an accurate simulation problems. The code calculation is based on the continuous energy ...

The Monte Carlo MVP code system was adopted for the Reaktor TRIGA PUSAPTI (RTP) core calculation. The code was developed by a group of researcher of Japan Atomic Energy Agency (JAEA) first in 1994. MVP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation and able to estimate an accurate simulation problems. The code calculation is based on the continuous energy ...

Fission product cross sections of intermediate-energy fission of 238U were used in order to construct the charge and mass yield distributions. Enriched target of 238U was irradiated by proton beam with energy 660 MeV for several hours at the LNP Phasotron, Joint Institute for Nuclear Research (JINR), Dubna, Russia. The charge distribution of the ...

The results of the Laser Fusion Breeder Design Study are given. This information primarily relates to the conceptual design of an inertial confinement fusion (ICF) breeder reactor (or fusion-fission hybrid) based upon the HYLIFE liquid metal wall protection concept developed at Lawrence Livermore National Laboratory. The blanket design for this breeder is optimized to both ...

The first measurement of proton, pion, and kaon associated fission of Bi nuclei has been performed in a photon energy range 1. 45 < E{sub {gamma}}< 1. 55 GeV. The fission probabilities are compared with an inclusive fission probabilities obtained with photons, protons and pions. The ...

Fission properties of proton-induced fission on Th232, Np237, U238, Pu239, and Am241 targets, measured at the Louvain-la-Neuve cyclotron facility at proton energies of 26.5 and 62.9 MeV, are compared with the predictions of the state-of-the-art nuclear reaction code talys. The code couples the multimodal random neck-rupture model with ...

The time scale of the fission process at moderate to high excitation energies is determined by shape-dependent and, most likely, temperature-dependent nuclear dissipation. Most of the present knowledge about the time scale of nuclear fission has been deduced from measurements of multiplicities and the energy spectra of neutrons, light charged particles, ...

Measurements were conducted for the fission neutron yields with fission fragments in the (d,pf) reactions at some excitation energies, where threshold neutrons were discovered. These data on the neutron yields in 233U(d,pfn) and 239Pu(d,pfn) reactions have been compared with the dependence of the average of fission ...

The �Energy plus Transmutation� experimental setup of the Joint Institute for Nuclear Research (JINR), Dubna, Russia, is a lead target surrounded by a natural uranium blanket. A polyethylene plus cadmium shield is placed around the target blanket assembly to modify the spallation and fission neutron spectra in the system. In this work the spatial distribution of natural ...

Fission fragment kinetic energy distributions have been measured separately for two spontaneously fissioning isomers of 237Pu produced by the 237Np(d, 2n)237Pum reaction at 13 MeV. Single fragment peak to valley ratios and heavy and light fragment peak positions were measured for each of the two isomers. Average fragment kinetic energies for each isomer ...

First moments and variances of measured rubidium and cesium isotopic distributions in the fission of /sup 238/U by /sup 11/B(E/sub lab/ = 85 MeV) and /sup 22/Ne (E/sub lab/ = 132 and 162 MeV) are analyzed in the framework of the statistical model for nuclear fission and of evaporation theory. Excellent agreement with the data is obtained for /sup ...

The angular distribution of fission fragments for the 32S+184W reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1 and 144.4 MeV were measured. The experimental fission excitation function is obtained. The fragment angular anisotropy is found by extrapolating the fission angular distributions. The measured ...

Fission cross sections in statistical model of fission are calculated using one of important parameter such as transmission coefficients. This parameter calculated using optical model parameter and level density. There are several models of level density that can be used to predict fission cross section. They are Constant Temperature ...

Fission cross sections in statistical model of fission are calculated using one of important parameter such as transmission coefficients. This parameter calculated using optical model parameter and level density. There are several models of level density that can be used to predict fission cross section. They are Constant Temperature ...

Yields of correlated fragment pairs were obtained in spontaneous fission of {sup 242}Pu. Charge, mass and neutron multiplicity distributions of fragment pairs were determined and compared to available data. The yield of cold fission without neutron emission was determined to about 10{percent} for the set of observed correlated fragment ...

Yields of correlated fragment pairs were obtained in spontaneous fission of {sup 242}Pu. Charge, mass and neutron multiplicity distributions of fragment pairs were determined and compared to available data. The yield of cold fission without neutron emission was determined to about 10% for the set of observed correlated fragment pairs.

A theoretical analysis of the behavior of an electrostatic precipitation wire machine is presented. Curves based on the theoretical predictions and previously published experimental data on the fission products of uranium are compared to enable estimates to be made of the performance or fission product measurement systems. ...

The mass distribution in fission of natural lead induced by 54 Mev protons was studied. The yield mass curve seems nearly symmetric in character around mass number 102. It has a width of about 28 mass units at half the maxi- mum yield. The fission cross section is 13 plus or minus 4 mb, which is the same as for bismuth under ...

In order to study the influence of fluctuations on various phenomena linked to heavy ion collisions, a Langevin equation has been derived from a microscopic model. Parameters entering this equation are completely determined from microscopic quantities characterizing nuclear matter. This equation has been applied to various phenomena at intermediate energies. This paper focuses on large amplitude ...

A method for dating geological samples which uses fission product xenon in a manner similar to the use of radiogenic argon in the $sup 40$Ar--$sup 39$Ar technique has been developed. The results of stepwise heating experiments for a zircon from the Ahaggar region in the Sahara are compared to the geochronology determined by the ...

Half-lives for spontaneous fission of nuclides with even and odd numbers of particles are compared with recent theoretical calculations. A summary of odd particle hindrance factors is given. The most recent measurements of kinetic-energy and mass distributions and neutron emission for spontaneous fission of the heaviest nuclides are ...

The relative biological effectiveness (RBE) values for low doses of fission neutrons compared to 60 Co gamma rays were determined with four separate assessments of genetic damage induced in young hybrid male mice. Both radiations were delivered at low dos...

The range distribution of U/sup 233/ fission fragments (Sr/sup 91-92/, Ce/sup 143/) in various gases is studied. The dependence of the range dispersion on the nature of the gas wse established. From the range dispersion the kineticenergy dispersion due only to fission processes was determined. The results are compared with ...

Fission barriers calculated from the rotating liquid drop model with finite-range corrections based on scaling of the nonrotating finite-range model of Krappe et al. are compared with results explicitly calculated for rotating systems with the finite-range effect included. The scaling method is shown to give excellent agreement with the calculated ...

Recent measurements of neutron emission in coincidence with fission fragments indicate a strong enhancement of the neutron multiplicity preceding fission compared with statistical model calculations. This enhancement has enabled the determination of the reduced nuclear dissipation coefficient ..beta.. which, in turn, indicates that ...

The author measured the radiative capture-fission cross-section ratio ( alpha ) for exp 239 Pu with a resolution delta t/L=0.23 mu sec/m. The experimental method consisted in comparing the scintillation-detector count of gamma quanta and prompt fission ne...

A process is given for determining the neutronic purity of fissionable material by the so-called shotgun test. The effect of a standard neutron absorber of known characteristics and amounts on a neutronic field also of known characteristics is measured and compared with the effect which the impurities derived from a known quantity of ...

In July 1977 the International Intitute for Applied Systems Analysis at Laxenburg, Austria, published a detailed report (hereafter called I), in which fission and fusion reactors were compared. Data of fission reactors were mainly taken from the SNR-300; ...

The interaction of mu /sup -/ mesons at 150 Mev with U/sup 238/ was investigated using nuclear emulsions. The experimental set-up and the development of the emulsion are described. Some 26,975 cases of the stopping of the mesons in the emulsion were investigated, and 59 cases of fission were observed. The fission probability was considered on ...

The statistical model of fission is used to calculate the charge distributions of fission fragments of /sup 236/U* and their dispersion as a function of the excitation energy and angular momentum of the compound nucleus. The potential of the two-center oscillator was chosen as the single-particle potential. The influence of the parameters of the ...

We present the first results on the bremsstrahlung emission of photons accompanying ternary spontaneous fission of the 252Cf nucleus. We also compare our calculations on the basis of quantum model with preliminary experimental data and find a good agreement between theory and experiment for photon energies up to 500 keV, when the ?-particle emission is in ...

Fission products were lumped together either into fast, slow, and non- burning elements or into a non-burning element and samarium-149. These elements were then used in burnup studies of two reactors. The results were compared with similar results obtained by experiment or by different formulations of fission product elements. ...

The neutron-induced fission cross section of U-235 is not only one of the most-frequently used references but is also of direct importance in reactor applications. As a consequence, knowledge of this cross section is required with approx. 1% uncertainty as reflected in corresponding entries in request lists, which have persisted since the last 10 to 15 years. Measurements to ...

A relationship was studied between fission and restoration of body and its individual parts under different experimental conditions in planarians of the Dugesia tigrina asexual race. The body and its fragments were studied morphomterically. After fission, the growth of planarians demonstrated topographic differences. The separated tail fragments and ...

A search was made for Coulomb fission induced by /sup 84/Kr ions on a / sup 238/U target at energies ranging from the interaction barrier down to 37 MeV below (408 to 455 MeV lab). No event attributed to Coulomb fission was detected; it was deduced that the cross section for this reaction is lower than 0.3 mb/sr near the interaction barrier. This ...

A preliminary evaluation of the fission cross-section of /sup 235/U from 100 keV to 20 MeV is described. Variance-covariance matrices for a number of experimental data sets were constructed and used to evaluate the fission cross-section following a Bayesian procedure. The evaluated fission cross-section is compared ...

The Bardeen, Cooper, Schrieffer formalism is applied to a calculation of the mean-square projection K02 of the angular momentum along the symmetry axis of an excited deformed nucleus. The results are compared with empirical values obtained from analysis of recent data on fission-fragment angular distributions. The comparison corroborates qualitatively the ...

Single fragment and total kinetic energy distributions have been measured for fission induced by helium ions and deuterons in Au, Tl, Pb, and Bi targets. The average total kinetic energy release has the same proportionality with Z2A13 found for fission of heavier elements. The widths for the total kinetic energy distributions are ...

Single-fragment and total kinetic energy distributions were measured for fission induced by helium ions and deuterons in Au, Tl, Pb, and Bi targets. The average total kinetic energy release has the same proportionality with Z/sup 2//A/ sup 1/2/ found for fission of heavier elements. The widths for the total kinetic energy distributions are ...

The rationale for developing hybrids depends on real or perceived liabilities of relying on pure fission to do the same job. Quite possibly the main constraint on expanded use of fission will be neither lack of fuel nor high costs, but perceived environmental liabilities - radioactive wastes, reactor safety, and links to nuclear weaponry. The environmental ...

The multiplicities of energetic [gamma] rays have been measured in coincidence with both evaporation residues and fission fragments in the reactions of [sup 19]F on [sup 181]Ta at projectile energies of 90, 100, 110, 120, 130, and 140 MeV. The experimental data have been compared with results of statistical calculations which take into account dynamical ...

The distribution of energies of the fragments from U235 fission produced by slow and by fast neutrons were compared. The energy was determined by using a 10-channel amplitude discriminator to analyze pulses from a Frisch-grid ionization chamber. No difference was found outside the experimental error. The energy distribution of the fragments from thorium ...

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the ...

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the ...

A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the ...

The cross section for {sup 244}Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective ...

The cross section for 244Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective ...

The energy spectrum of the high energy ?-rays in coincidence with the prompt ?-rays has been measured for the spontaneous fission of 252Cf. The nucleus-nucleus coherent bremsstrahlung of the accelerating fission fragments is observed and the result has been substantiated with a theoretical calculation based on the Coulomb acceleration model. The width of ...

Fission fragment mass distribution has been measured from the decay of 246Bk nucleus populating via two entrance channels with slight difference in mass asymmetries but belonging on either side of the Businaro Gallone mass asymmetry parameter. Both the target nuclei were deformed. Near the Coulomb barrier, at similar excitation energies the width of the ...

The fission cross sections and the fragment angular distribution have been measured in bombardment of Ag, In, Sn, and Sm by protons with energies 155 and 200 MeV. Solid-state track detectors in a circular geometry were used to record the fragments. It was found that fission of comparatively light nuclei occurs only in the case of ...

Advances achieved during recent years in model and ab initio descriptions of fission of metal clusters are reviewed. We focus on developments in ab initio treatment of the electronic subsystem within the jellium background model, as well as on applications of potential energy surface analysis to determining the characteristics of the ...

Proof-of-principle measurements are reported demonstrating that multiplicity techniques can be used to identify prompt fission neutrons from photonuclear interrogation under circumstances where the fission neutrons may be accompanied by photodissociated neutrons of an identical energy spectrum, and where the emitted neutrons are naturally bunched in time ...

Fission product release from the reactor core has been predicted by the reference design methods and compared with reactor surveillance measurements and with the results of postirradiation examination (PIE) of spent FSV fuel elements. Overall, the predictive methods have been shown to be conservative: the predicted fission gas release ...

Despite the huge number of fission yield data available in the different evaluated nuclear data libraries, such as JEFF-3.1.1, ENDF/B-VII.0, and JENDL-4.0, more accurate data are still needed both for nuclear energy applications and for our understanding of the fission process itself. It is within the framework of this that measurements on the recoil mass ...

Sodium has been used for nearly all of the terrestrial fast reactors. As compared to NaK, sodium has the advantages of higher specific heat (leading to ...