ISSN:0550-3043    

DOI:10.13182/NT70-A28758

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

ISSN:0550-3043    

DOI:10.13182/NT70-A28759

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractThis paper examines the neutron-energy spectra of sodium-cooled fast reactors, with primary attention given to the neutron-energy range from 30 keV to 10 MeV, the major source of irradiation damage in a fast reactor. The status of relevant fast neutron cross-section knowledge is examined, and the influence of cross-section uncertainties is included in the comparison of theoretical predictions with experiment. Also examined, are differences among various theoretical methods and problems in determining the spectrum in real systems with interfaces and heterogeneities. The current status of studies of the EBR-II flux and spectrum is summarized, including determination of absolute flux magnitude and two-dimensional estimates of the considerable influence of neighboring subassemblies and experimental heterogeneity on the very high energy spectrum. Finally, the relationship between flux monitor data, knowledge of spectra, and radiation damage is discussed.

ISSN:0550-3043    

DOI:10.13182/NT70-A28760

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractA nondestructive in-place test procedure was developed to measure the efficiency for iodine removal by charcoal filters in the Hanford reactors exhaust gas systems. Tests were performed during the past few months on the C, KE, and KW Hanford single pass production reactor systems. Results from tests conducted on individual reactor confinement cells showed iodine trapping efficiencies of from 94 to 98%. The experimental techniques and procedures used also facilitated the simultaneous measurement of iodine plateout in the reactor exhaust duct systems.

ISSN:0550-3043    

DOI:10.13182/NT70-A28761

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractThe Belgonucleaire-CEN research and development work, performed in the scope of a joint USAEC-EURATOM Program, involves the development of both fabrication techniques and methods of design calculations for plutonium-enriched cores. Based on experience gained since 1963, a specific study of plutonium recycle in the SENA reactor was undertaken in cooperation with EURATOM and the Belgian utilities. This study, confirmed by experiments carried out in the Belgian VENUS critical facility, has led to proposed optimized schemes for the composition and the location of plutonium-enriched fuel rods. For the conditions prevailing around 1973, it appears that, in the case of the SENA reactor, there should be a slight economic advantage in mixing the available plutonium with slightly enriched uranium arising from the reprocessing of the fuel assemblies rather than with natural or depleted uranium.

ISSN:0550-3043    

DOI:10.13182/NT70-A28762

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractBurst tests were conducted at 900°F on specimens prepared from 75% UO2−25% PuO2fuel pins clad with 0.250-in. o.d.×0.016-in. wall Type-304 stainless steel (PNL 1-3 and 1-6) that were irradiated in EBR-II to∼8500 MWd/MTM at 8 to 9 kW/ft. Argon gas was used internally to pressurize the fuel pin sections. The fuel was left intact in order that the effects of the fuel and fission products on the properties of the cladding could be determined.Specimens taken from above the midplane but within the fuel column exhibited brittle, intergranular fracture at drastically lower stresses (∼30 000 psi) than would be expected from Type-304 stainless steel irradiated under similar conditions. The measurable strain in these specimens was<1%.Fueled specimens from below the midplane and specimens from the fission gas plenum exhibited a ductile, transgranular fracture at stresses and strains normally expected of Type-304 stainless steel irradiated under these conditions, i.e.,∼60 000 psi and∼9% strain. Post-test examination of the burst test specimens included diameter measurements, optical metallography, and electron microscopy. Fueled specimens from above the midplane contained M23C6and sigma phase at the grain boundaries of the cladding whereas the cladding of specimens from below the fuel midplane was free of grain boundary precipitates.From the test results and examinations it is concluded that:Sections of irradiated fuel pins may fail at much lower stresses and strains than would be expected from mechanical tests conducted on unfueled cladding materialThe premature failure in certain sections of the pin is associated with grain boundary precipitation in the claddingThe precipitation is believed to promote chemical attack along the cladding boundaries where the chemical specie is either a fission product or a reaction product produced from their interaction with the hot cell environment.

ISSN:0550-3043    

DOI:10.13182/NT70-A28763

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractUranium-plutonium mixed oxide sol-gel fuel is attracting interest as a promising nuclear material for fast reactor fuel subassemblies.However, this material, if employed for commercial fuel production particularly in the fast reactor area, must be extensively tested both inpile and out-of-pile.For this purpose, some irradiation tests have been carried out by CNEN in the RS-1 swimming pool reactor in Italy and in the Halden BHWR in Norway under the Plutonium Program and the Fast Reactor Program.The results obtained show: in-reactor homogenization of plutonium in the UO2matrix, increase of the integral of conductivity after in-pile sintering process has taken place, and cladding attack caused by impurities originally present in the fuel particles.

ISSN:0550-3043    

DOI:10.13182/NT70-A28764

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractVarious alloys with face-centered cubic structures were irradiated to fast fluences of 1.5×1021n/cm2(E>I MeV) and tested in tension at elevated temperatures. The alloys that were investigated included pure nickel (99.999%), Nickel 200, a non-nickel manganese stabilized stainless steel (Tenelon), and two cobalt alloys. One of the cobalt alloys contained 10% nickel (Haynes Stellite-25) while the other was nickel free (UMCo-50). It was found that irradiation caused embrittlement in all of these alloys when they were tested in tension at elevated temperatures.

ISSN:0550-3043    

DOI:10.13182/NT70-A28765

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractTensile and creep-rupture data have been obtained at 700 and 760°C for several experimental heats of lncoloy 800 that were irradiated in the Oak Ridge Research Reactor (ORR) at elevated temperatures or held at control temperatures in the laboratory.Effects of composition, grain size, and stress level (or strain rate) on these strength properties were investigated. Enhanced postirradiation ductility was observed in Incoloy 800 containing∼0.1% Ti in creep-rupture tests. The maximum ductility for this composition was obtained in fine-grained specimens tested at low creep stress levels, and the ductility appeared to be unaffected by carbon content.The ductility of unirradiated material was also increased by decreasing either grain size or strain rate. Significant variations in properties (both control and postirradiation tests) were noted for alloys within the commerciallncoloy 800 specification range. The ductility peak at∼0.1% Ti is not fully understood; it might be best explained by two independent mechanisms, one accounting for the increasing ductility with increasing titanium at levels less than 0.1% and the other explaining the decreasing ductility at higher titanium levels. The grain size effect may be due to differences in the distribution of helium and/or trace elements or to a grain-size dependent variation in stresses necessary for grain boundary fracture. Higher postirradiation ductility at lower stresses could be due to stress relaxation, grain boundary migration, or less pronounced stress-induced growth of helium bubbles present in the grain boundaries.

ISSN:0550-3043    

DOI:10.13182/NT70-A28766

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor

摘要:

AbstractA new reentry protection material has been developed which acts as a thermal switch. It is a composite material, consisting of a ceramic foam uniformly impregnated with a metal which coats the ceramic foam structure. The composite is a thermal conductor [k≅5 Btu/(ft h°F)] below the melting point of the metal impregnant and switches to an insulator [k≅0.1 Btu/(ft h°F)] above its melting point. This switching effect is irreversible.Materials investigated to date are silica, alumina, and zirconia foams with silver and copper as the metal impregnants. These combinations yield a thermal switch which is activated at the melting point of the impregnants, i.e., 1762°F for silver and 1982°F for copper. Other metals can be utilized to increase or decrease the switching temperature.These composite materials have specific application to radioisotope fueled space power systems. For this application, the material selected would be placed around the fuel capsule, allowing the heat to pass through with only a small temperature differential incurred. When exposed to a reentry heat pulse, the material would switch to an insulator, thereby allowing intact and safe reentry of the capsule.Thermal conductivity testing and plasma jet testing have been performed and indicate that the composite material is an effective reentry protection material.

ISSN:0550-3043    

DOI:10.13182/NT70-A28767

出版商:Taylor&Francis    

年代:1970

数据来源: Taylor