Absolute exp 239 Pu thermal fission yields are given for the stable and long-lived isotopes of krypton, rubidium, strontium, zirconium, xenon, cesium, barium, cerium, neodymium, and samarium. The principal measurement technique for the fission product iso...

Absolute exp 235 U thermal fission yields are given for the stable and long-lived isotopes of krypton, rubidium, strontium, zirconium, molybdenum, ruthenium, xenon, cesium, barium, lanthanum, cerium, neodymium, and samarium. The principal measurement tech...

A method for the experimental determination of the capture-to-fission ratio (alpha) in low-flux reactors is outlined. The procedure utilizes pile oscillator techniques but does not require an absolute determination of either the reactivity or the reactor power. A spontaneous fission source is used to establish the importance ...

Absolute /sup 239/Pu thermal fission yields are given for the stable and long-lived isotopes of krypton, rubidium, strontium, zirconium, xenon, cesium, barium, cerium, neodymium, and samarium. The principal measurement technique for the fission product isotopes was isotope dilution mass spectrometry. The number of ...

The fission product chains resulting from thermal neutron fission of exp 235 U are given as compiled from the latest tabulated data. Included are the calculated absolute cumulative yields, single particle model states for protons and neutrons and experime...

An examination of the standard methods of determining the fission cross section shows that the principle sources of error are uncertainties in the spectrum of the incident neutrons, the energy dependence of the cross sections of the material being studied, the thickness of the fission foil, and the value of some reference cross section. A new ...

The results of extensive SSTR measurements made at the Pool Critical Assembly (PCA) facility at Oak Ridge National Laboratory have been reported previously. Measurements were made at key locations in PCA which is an idealized mockup of the water gap, thermal shield, pressure vessel geometry of a light water reactor. Recently, additional SSTR fission rate ...

Radiochemically determined mass-yield curves are given for the fission of U/sup 235/ and U/sup 238/ by l4.7-Mev neutrons. Symmetric and to a less extent, very asymmetric modes of fission are more probable at that energy than in thermal fission. Yields of four fission products from ...

An absolute calibration technique for a spontaneously fissioning nuclide (which involves no arbitrary parameters) allows unique determination of the detector efficiency for that nuclide, hence of the fission source strength.

A review is presented of absolute meaurements of anti ..nu.. for the spontaneous fission of /sup 252/Cf and of relative measurements for thermal-neutron-induced fission of /sup 233/,/sup 235/U and /sup 239/,/sup 241/Pu. The discussion includes the consideration of a number of sources of revision that have been ...

Fission cross section measurements for a collection of uranium and plutoninm isotopes are presertly being made at LLL by using the 100-MeV electron linear accelerator as a pulsed source for neutrons. The cross sections are measured as a function of neutron energy from 15 MeV down to thermal energy by using the time-of-flight technique. For ...

We propose an improved equation for calculating the uranium concentration in thick samples based on induced fission-track counts in an external detector that takes into consideration (1) the fission-fragment ranges in the sample and external detector, (2) the etchable track length and (3) the track counting efficiency in the external detector. The values ...

Neutron capture and fission reaction cross sections are usually measured relative to a standard basis. The most common absolute cross sections which are used in the thermal neutron energy region are sup 197 Au and sup 59 Co for capture reactions and sup 2...

The absolute abundances of the isotopes of fissionproduct xenon and krypton in six uranium minerals were determined mass spectrometrically using the isotope dilution technique. The fission products were resolved into a U/sup 238/ spontaneous fission component, a U/sup 235 neutron-induced fission component, ...

Neutron capture and fission reaction cross sections are usually measured relative to a standard basis. The most common absolute cross sections which are used in the thermal neutron energy region are /sup 197/Au and /sup 59/Co for capture reactions and /sup 235/U and /sup 239/Pu for fission reactions. Values for ...

Absolute yields have been determined for 105 gamma rays emitted in the decay of 95 fission products representing 54 mass chains created during thermal-neutron fission of 245Cm. These results include 17 mass chains for which no prior yield data exist. Using a Ge(Li) detector, spectra were obtained of gamma rays ...

... Accession Number : AD0616613. Title : AN ABSOLUTE MEASUREMENT OF THERMAL NEUTRON ALBEDO FOR SEVERAL MATERIALS. ...

The effects of thermal flux peaking in moderator regions near the fuel may be used to build research reactors in which a maximum thermal flux may be produced with minimum reactor power. A succession of cores of annular shape enclosing a central cylindrical thermal column was investigated in order to chart the changes of the ...

A prototype fission chamber was tested and several chambers were built. The design and performance characteristics are presented. (FS)

Absolute cumulative yields have been determined for 49 fission products representing 36 mass chains created during thermal-neutron fission of /sup 239/Pu, including 3 mass chains for which no prior data exist. Using Ge(Li) spectroscopy, spectra were obtained of gamma rays from decay of fission ...

... RADIOACTIVE ISOTOPES, SEPARATION, ION EXCHANGE, FISSION PRODUCT ... PHYSICS RADIOACTIVITY, RADIOACTIVE WASTES & FISSION ...

The part of the FFTF Reactor Characterization Program reported in this paper is a measurement of absolute fission rates of eight major fuel isotopes at two different positions within the reactor. The instruments employed in these tests were fission ioniza...

The procedures and status of the absolute measurement of the neutron capture cross sections for exp 115 In and exp 232 Th are described. Work on the exp 239 Pu fission fragment anisotropy and absolute measurement of the fast neutron fission cross section ...

... FISSION, FISSION PRODUCT ACTIVITY, NUCLEAR ISOBARS, NEUTRON REACTIONS, THERMAL NEUTRONS, RADIOACTIVE ISOTOPES ...

Absolute yields have been determined for 107 gamma rays emitted in the decay of 97 fission products representing 54 mass chains created during thermal-neutron fission of 249Cf. These results include 14 mass chains for which no prior yield data exist. Using a Ge(Li) detector, spectra were obtained of gamma rays ...

Absolute yields have been determined for 47 gamma rays emitted in the decay of 37 fission products representing 25 mass chains created during thermal-neutron fission of 229Th. Using a Ge(Li) detector, spectra were obtained of gamma rays emitted between 15 min and 0.4 yr after very short irradiations by ...

The experimental data given in AERE-R 4173 were reevaluated and the absolute value of alpha /sub O/ for Pu/aup 239/ was found to be 0.356 plus or minus 0.013. A number of alphas for a reactor spectrum and for 2200 m/sec neutrons were re-calculated, and some additional possible systematic errors were considered. (auth)

A method is described for correcting for effect of isotope burn-in in fission neutron dosimeters. Two quantities are measured in order to quantify the "burn-in" contribution, namely P.sub.Z',A', the amount of (Z', A') isotope that is burned-in, and F.sub.Z', A', the fissions per unit volume produced in ...

Fission-track registration characteristics of Lexan plastic track detector immersed in aqueous solution of uranyl nitrate have been studied. An attempt has been made to measure absolute fission yields of some fission products in the 14 MeV induced fission of 238U using track etch-cum-gamma ray ...

The interaction of thermal neutrons with a coin shaped detector is discussed in terms of the reaction rate in an infinite sheet of pure absorber irradiated in a void by an isotropic, Maxwell distribution of thermal neutrons. A coincidence method for the evaluation of the decay rate of the neutron induced activity in gold is examined in detail and ...

... Title : INADEQUACY OF THERMAL INITIATION THEORY IN INTERPRETING RESULTS OF FISSION-FRAGMENT IRRADIATION OF EXPLOSIVES ...

The aim of this paper was the measurement of the integral beta spectrum of the fission products of exp 235 U after thermal fission. (Atomindex citation 13:713181)

... 99. With this ratio and pertinent data from the thermal neutron fission of U-235, the mass chain yield was calculated. The ...

This patent broadly discloses the production of plutonium by the neutron bombardment of uranium to produce neptunium which decays to plutonium, and the fissionability of plutonium by neutrons, both fast and thermal, to produce energy and fission products.

... on gamma-ray exposure rates in fission-product fields, spectra of gamma-rays emitted by fractionated products of thermal neutron fission of 235U ...

... FISSION PRODUCT MIXTURES IV GAMMA IONIZATION CHAMBER MEASUREMENTS FOLLOWING THERMAL NEUTRON FISSION OF PU 239. ...

Fast neutron detection has applications in a number of topic areas, including national security and nuclear fuel cycle safeguards. Ideally, these sensors would have high sensitivity to fission (fast) neutrons but be insensitive to thermal neutrons and gamma rays. This paper describes a study of actinide-loaded glass for fast neutron detection, wherein a ...

A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises ...

The purpose of the project described is to study fission product decay heating rates, with emphasis on short decay times. Isothermal calorimetry is used to perform benchmark experiments for decay times between 20 seconds and 2000 seconds with an absolute accuracy of better than 5 percent. Experiments are being done with $sup 235$U and will be ...

... Title : Absolute Length Changes by Remote Interferometry. ... Descriptors : *Interferometers, *Dilatometers, *Thermal stability, *Change detection ...

Absolute (n, gamma ) cross-sections of some fission products with high yield have been measured. In addition, Fe has been studied to remove some unexplained discrepancies in earlier crosssection measurements. Both the gamma and the neutron detector have been calibrated absolutely, so the values derived are not normalized to ...

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 ...

Values of effects of parity nonconservation in binary and ternary fission of plutonium 239 by polarized thermal neutrons were measured simultaneously. The ratio of asymmetry coefficient (AC) of ternary fission to the AC of binary fission was equal to 0.67...

A least squares analysis of fission neutron standard fields has been performed using the latest dosimetry cross sections. Discrepant nuclear data are identified and adjusted spectra for {sup 252}Cf spontaneous fission and {sup 235}U thermal fission fields are presented.

As part of a study of nuclear charge distribution in the region of symmetric fission, the existence and cumulative fission yield of 117Pd were sought. Palladium was isolated free from silver and cadmium at different times after fission and the quantity of...

Five general areas of application for nuclear cross sections have been identified for benchmark testing by the Cross Section Evaluation Working Group (CSEWG); thermal and fast reactors, shielding, dosimetry and fission product properties. For both thermal and fast reactors, benchmark experiments consist of measurements of ...

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 ...

A source of fission product recoil energy suitable for use in radiation chemistry is reported. The source consists of thermal neutron irradiated glass wool having a diameter of 1 to 5 microns and containing an isotope fissionable by thermal neutrons, such as U/sup 235/.

Beta and gamma fission product decay heat curves are evaluated for the thermal fission of exp 235 U. Experimental data that include beta, gamma, and total measurements are combined with summation calculations based on ENDF/B in a consistent evaluation. Le...

Measurements in AFSR of the changes in some fission ratios which result from the proximity of relatively small quantities of steel and polyethylene are described. The results show that some of the measurements with the Kirn absolute fission chambers in ZPR III are probably in error by several percent. (auth)

Jan 4, 2010 ... Thermal Energy Conversion Branch. Home � News � Radioisotope Power Systems � Fission Surface Power � Thermal � Past Projects � Publications ...

... ROCKET PROPELLANTS, URANIUM COMPOUNDS, FISSION PRODUCTS, NITROGEN, FLUORINE, THERMAL NEUTRONS, AZINES. ...

The first in a series of quarterly progress reports on ERDA budgeted activities subcontracted to Allied Chemical Corporation at the Idaho National Engineering Laboratory is presented. The work is performed by the Technical Division and is divided into three subjects. Fuel cycle research and development includes fluidized-bed calcination and post treatment of commercial nuclear fuel process waste; ...

Time, temperature and the kinetics of reactions are the basic ingredients in this study of thermal history analysis. Unraveling the timing of geological events using absolute dating systems based on radioactive decay is not a trivial task, ages given by most radiometric dating techniques (e.g. fission track analysis) are apparent ages, ...

On the basis of measured yields for 72 gamma rays and known nuclear data, cumulative fission-product yields were deduced for 69 fission products having half-lives between 36 seconds and 65 days representing 41 mass chains created during thermal-neutron fission of 243Cm.

The fission product Ba/sup 140/ is often used as a standard in fission yield determinations. A method is presented for this determination from the thermal neutron fission of U/sup 235/ The fission yield of Ba/sup 140/ was found by this method to be 6,36 plus or minus 0.12%, which ...

Cumulative fission yield of 148 cesium isotopes and some other fission products produced by thermal-neutron fission of 235 uranium is determined by Germanium/Lithium spectroscopic methods. The measuremets were done at Tsing-Hua open pool reactor using 3 t...

This patent relates to nuclear reactors of tbe type utilizing a liquid fuel and designed to convert a non-thermally fissionable isotope to a thermally fissionable isotope by neutron absorption. A tank containing a reactive composition of a thermally fissionable ...

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...

Absolute fission yield data are presented for exp 237 Np irradiated in EBR-II. The measurement technique was isotope dilution mass spectrometry. This is believed to be the first published set of comprehensive exp 237 Np yield data based on mass spectromet...

lute basis by Diven by using the known capture plus fission cross section of U235 ... Cox employed absolute 7-counting and used the U235 fission cross section ...

Strontium-90 and yttrium-90 are two of the important fission products. At present they are applied widely in industry because their half life is longer and their fission yield is higher. The radioactivity of the nuclide is of concern, because strontium-90...

Published radiochemical measurements of yields from the fast fission of U-238 are reviewed, and a complete set of yields between masses 77 and 161 is recommended for use in fission product poisoning calculations. The pseudofission- product treatment is adopted to simplify presentation and handling of the data. The fission ...

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location ...

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location ...

The absolute fission yields of 46 fission products in {sup 238}U (99.9997 at.%), 46 fission products in {sup 237}Np, 27 fission products in {sup 238}Pu (99.21 at.%), 30 fission products in {sup 240}Pu (99.48 at.%), 30 fission products in {sup 243}Am ...

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain Q in DD operating tokamaks. Total neutron yield is measured with (sup 235)U and (sup 238)U fission chambers and (sup...

... TEST REPORT FOR TRANSDUCER-ABSOLUTE PRESSURE STRAIN ... THERMAL SHOCK, THERMAL STABILITY, VIBRATION, ELECTRICAL ...

A new, interferometer-based system for measuring thermal expansion to an absolute accuracy of 20 ppb

A new, interferometer based system for measuring thermal expansion to an absolute accuracy of 20 ppb

... in space nuclear thermal and electric propulsion reactors. In the Uranium Arc Fission Reactor, arcs are ... The arcs operate at 10,000 K, and transfer ...

... C-CI bond fission would not have occurred with thermal excitation since ... 1) in the C-CI bond fission channel suggest that this selective dissociation ...

Nuclear Reactor (core) produces thermal energy via fission of U-235. Fission reaction rate (power) actively and passively controlled by neutron balance ...

... and the largest E. The spectral shape is probably related to the fact that the heavier fissionable isotopes produce fission fragments whose mass ...

The paper presents a preliminary uncertainty analysis related to potential uncertainties on the fission spectrum data. Consistent results are shown for a reference fast reactor design configuration and for experimental thermal configurations. However the ...

Uranium fission fragment damage in thermally unstable crystals is considered. Thin single crystals of silver cyplease delete the above abstract no. 34506===

Oct 16, 2007 ... This project develops the heat pumps, evaporators, and radiators for thermal control of Orion, ... Read the List of Publications by Experiments ... fission reactor on the moon, Fission Surface Power Systems ...

microscopic fission cross section macroscopic absorption cross section, excluding fuel macroscopic absorption cross section of fuel neutron age to thermal ...