Low specific activity material

The term unirradiated thorium in the definition of low specific activity material is intended to exclude any thorium which has been irradiated in a nuclear reactor so as to transform some of the Th-232 into U-233, a fissile material. The definition could have prohibited the presence of any U-233, bnt naturally occurring thorium may contain trace amounts of U-233. The limit of 1(U g of U-233 per gram of Th-232 is intended to clearly prohibit any irradiated thorium while recognizing the presence of trace amounts of U-233 in natural thorium. 

LAUTERBACH, U., Radiation level for low specific activity materials in compact stacks . Packaging and Transportation of Radioactive Materials, PATRAM 80 (Proc. Symp. Berlin, 1980), Bundesanstalt fur Materialprilfung, Berlin (1980). 

Low specific activity materials with unlimited Aj or Aj values... 

If only melting occurs, an explanation for the bell-shaped distribution of specific activity must take into account an incursion of material of low specific activity at the small sizes which still experienced sufficiently high temperatures to melt. 

This study on the immobilization of glucose oxidase and the characterization of its activity has demonstrated that a bioactive interface material may be prepared from derivatized plasma polymerized films. UV/Visible spectrophotometric analysis indicated that washed GOx-PPNVP/PEUU (2.4 cm2) had activity approximately equivalent to that of 13.4 nM GOx in 50 mM sodium acetate with a specific activity of 32.0 U/mg at pH 5.1 and room temperature. A sandwich-type thin-layer electrochemical cell was also used to qualitatively demonstrate the activity of 13.4 nM glucose oxidase under the same conditions. A quantitatively low specific activity value of 4.34 U/mg was obtained for the same enzyme solution by monitoring the hydrogen peroxide oxidation current using cyclic voltammetry. Incorporation of GOx-PPNVP/PEUU into the thin-layer allowed for the detection of immobilized enzyme activity in 0.2 M sodium phosphate (pH 5.2) at room temperature. 

On the other hand, in the case of enzymes with low specific activity, tight packing in crystals may be a useful fixation method when excessive inert carrier material would otherwise preclude reasonable reaction conditions. 

It has been observed and reported in the literature that further purification of low specific activity F-II did not help in increasing the biological activity of the material. At this stage, then the following points were considered ... 

Lowering of enzyme loading is recommended for enzymes with high specific activity which is easily achieved by common fixation methods. Enzyme activity in crystals was diluted by co-crystallization with inactivated enzyme [6]. On the other hand, in the case of enzymes with low specific activity, tight packing in crystals may be a useful fixation method when excessive inert carrier material would otherwise preclude reasonable reaction conditions. 

This estimate is compared to the specific activity of likely sources (upland and marine) in Table XIII. It appears that neither material scoured from the mud-water interface of Long Island Sound nor material eroded from the upland surface is an allowable source, since only material from beneath these surfaces is of sufficiently low activity. It is relatively difficult to effect deep (18-20 cm) erosion of submarine sediment in Long Island Sound, but common for upland soil to erode deeply, especially when land is disturbed by agriculture or construction. This indicates that the source of low-specific-activity inorganic matter is the eroding subsurface material of the watershed. 

A package of low specific activity radioactive material, when being transported in a transport vehicle assigned for the sole use of the consignor under Section 173.392(b),... 

See 173.389 (c) and 173.389 (o), for full-load shipments of radioactive materials meeting the definition of low specific activity when transported pursuant to 173.392 (b). 

Of special importance are Low specific activity (LSA) materials. LSA is radioactive material which by its nature has a hmited specific activity, or radioactive material for which hmits of estimated average specific activity apply. External shielding materials surrounding the LSA material shall not be considered in determining the estimated average specific activity. 

Less dangerous radioactive materials permit less stringent packages. Specifically, Industrial Package Types 7, 2, and 3 are in use for low-specific activity (LSA) materials and surface-contaminated objects (SCO) ... 

Radioactive materials are grouped according to their form and/or characteristics. These include Special Form Low Specific Activity (LSA) Surface Contaminated Object (SCO) Fissile Other Form. A radioactive material may meet the definition of one or more of the above. lATA 10.3.3... 

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