Measurement of Particulate Airborne Fission Products at Ground Level

Daily measurements are reported of the concentration of air-borne fission products at ground level in Canada during the period from late 1957 to the end of March 1959. The measurements, conducted at 14 stations throughout Canada, were part of the Canadian program for the International Geophysical Year and International Geophysical Co-operation. The results are given in the form of charts for each of the 14 stations, and monthly averages for each of the stations are tabulated.

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Site Survey of Former Naval Base in Andreyev Bay, Northwest-Russia: Radiation Levels and Radionuclide Concentrations On and Below the Surface Level

11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2007-7148 ◽

2007 ◽

Author(s):

Ole Reistad ◽

Frits Steenhuisen ◽

O̸ystein B. Dick ◽

Gisle Grepstad ◽

Styrkaar Hustveit ◽

...

Keyword(s):

Dose Rate ◽

Spent Nuclear Fuel ◽

Fission Products ◽

Ground Level ◽

Exceptional Case ◽

Activity Levels ◽

Accident Risk ◽

Building Structures ◽

Surface Level ◽

Naval Base

This paper presents the main results of the program to examine radiation levels and radionuclide concentrations on and below the surface level at the former Russian naval base in Andreyev Bay, Murmansk County. Presently, this base represents an exceptional case regarding future remediation and cleanup operations due to the accident risk (∼ max. fuel inventory of 100 submarine cores) and degree of contamination (over 25 years with continuous release — still ongoing — of radionuclides into the terrestrial and marine environment). The first part of the survey consists of about 1030 measurement points established as a grid with 10 m and 5 m mesh size for the measurement of dose rate in two heights above the ground level (0.1 m, 1 m), radionuclide concentrations, drilling of 50 boreholes for further examination of the radionuclide releases on site and the establishment of a 1:500 map of the area. These surveys were completed 2002–04. The results for dose rate measurements taken 1 m above the ground level varies between background levels and 3 mSv/h. Additional measurements were completed around the main building structures at the site and as part of a geological survey of the site. The activity concentration levels for Cs-137 and Sr-90 were measured in 250 points being part of the same measurement grid as above. The results for both isotopes range from normal fallout levels from atmospheric nuclear weapons testing to above 1 MBq/kg. The main conclusion is that continuous releases of fission products from spent nuclear fuel and fuel residues in defect storage pools have, together with inadequate storage facilities for large amounts of solid radioactive waste, led to heavy contamination of fission products in large areas. The 1:500 map is not public accessible. Thus, the second part of the survey was to analyse and document the results in adequate maps. These maps, geo-referenced to the UTM WGS84 system, have been established on the basis of commercial available satellite images from 2004 and show the measurement grid and results for radiation and activity levels in addition to coastline contour and selected infrastructure elements.

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Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

International Astronomical Union Colloquium ◽

10.1017/s0252921100080520 ◽

1976 ◽

Vol 32 ◽

pp. 169-182

Author(s):

B. Kuchowicz

Keyword(s):

Nuclear Physics ◽

Nuclear Reactions ◽

Chemical Elements ◽

Fission Products ◽

Abundance Pattern ◽

Isotopic Shifts ◽

Processed Material ◽

R Process ◽

Ap Stars ◽

Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

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Irradiation behavior of pyrolytic silicon carbide

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074288 ◽

1983 ◽

Vol 41 ◽

pp. 72-73

Author(s):

R. J. Lauf

Keyword(s):

Silicon Carbide ◽

Fission Products ◽

Thermodynamics And Kinetics ◽

Neutron Fluences ◽

Fuel Particles ◽

Sic Coatings ◽

Irradiation Behavior ◽

Kinetics Of ◽

Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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Effects of Vibration on the Preparation of Ultrathin Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007223x ◽

1973 ◽

Vol 31 ◽

pp. 358-359

Author(s):

Joseph M. Blum ◽

Edward P. Gargiulo ◽

J. R. Sawers

Keyword(s):

Cutting Speed ◽

Ground Level ◽

Environmental Vibration ◽

Block Face ◽

Ultrathin Sections ◽

Embedding Medium ◽

Thickness Variations ◽

Building Walls ◽

Cutting Direction ◽

Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

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TEM studies of amorphization processes and amorphous structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104303 ◽

1988 ◽

Vol 46 ◽

pp. 448-449

Author(s):

T. E. Mitchell ◽

R. B. Schwarz

Keyword(s):

Amorphous Materials ◽

Fission Products ◽

Rapid Quenching ◽

Surface Films ◽

List Type ◽

Oxide Glasses ◽

Crystalline Materials ◽

Amorphous Structures ◽

Amorphous Surface ◽

Interfacial Films

Traditional oxide glasses occur naturally as obsidian and can be made easily by suitable cooling histories. In the past 30 years, a variety of techniques have been discovered which amorphize normally crystalline materials such as metals. These include [1-3]:Rapid quenching from the vapor phase.Rapid quenching from the liquid phase.Electrodeposition of certain alloys, e.g. Fe-P.Oxidation of crystals to produce amorphous surface oxide layers.Interdiffusion of two pure crystalline metals.Hydrogen-induced vitrification of an intermetal1ic.Mechanical alloying and ball-milling of intermetal lie compounds.Irradiation processes of all kinds using ions, electrons, neutrons, and fission products.We offer here some general comments on the use of TEM to study these materials and give some particular examples of such studies.Thin specimens can be prepared from bulk homogeneous materials in the usual way. Most often, however, amorphous materials are in the form of surface films or interfacial films with different chemistry from the substrates.

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