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7. ASSAY OF RADIACTIVE WASTE
Pages 143-158

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From page 143... ... Some major characteristics of the nuclides needed to be analyzed are listed in Table 7-2 Many of these nuclides do not emit measurable gamma rays in their decay and can be measured only through difficult and time-consuming radiochemical and nuclear counting processes, requiring techniques and equipment beyond the capability of most nuclear power plant on-site laboratories. Even in some reputable laboratories, significant differences in the results of some comparative analyses have been reported(2) Read the entire page →
From page 144... ... Practical considerations such as heating effect, external package radiation on shipping, or maximum specific activity determine the maximum concentration for these nuclicles. Read the entire page →
From page 145... ... Variable Mostly alpha Multiple n-capture Fuel * TRU = Transuranic isotopes, excluding beta emitter Pu-241 and shorter-lived Cm-242 7-3 Read the entire page →
From page 146... ... utilize sampling equipment/techniques which do not bias samples, and (3) adopt sampling techniques which approximate random sampling. Read the entire page →
From page 147... ... Concentration units for these nuclides are nCi/g. DAW = clry active waste; concentrations are based on contact dose rates of 10mR/h. Read the entire page →
From page 148... ... c. DAW = d~y active waste; concentrations are basec3 on contact dose rates of 10 mR/h. Read the entire page →
From page 149... ... It is important that the sampling equipment produces the required size and quantity of individual grabs required for compositing a representative sample which can be handled for laboratory analytical evaluations. The sampling process should be performed on the transfer line to the waste container during the period of transfer. Read the entire page →
From page 150... ... Solids dry: weigh ash: weigh total dissolution HE, HNO3, HC1, H3BO3 (residue metathesis if needed) STOCK SOLUTION Usually ON HNO3 Carrier and Tracer free Aliquots for: o Liquids plus Pulp filter ash and dissolve filter reconstitute the sample gross alpha check 0 gross TRU evaluation 0 prime separation for Ni, Sr, Cs, U Read the entire page →
From page 151... ... Generally, a high resolution germanium detector is installed in a heavily shielded collimator, which is positioned properly toward the target waste container or waste transfer line. The direct assay technique generally gives fast and accurate assays of bulk waste with no personnel radiation exposure from sampling. Read the entire page →
From page 153... ... Calibration of the system makes it possible to convert the measured gamma-ray intensities into concentrations of gamma-emitting nuclides contained in the radwaste. The conversion factors should include the correction factors for various collimators, detector configurations and counting geometries, in addition to counting efficiencies as a function of gamma-ray energy. Read the entire page →
From page 154... ... Since the waste is frequently inhomogeneously mixed in the container, it is desirable to scan the entire portion of the container containing the waste. An ideal geometry is with the axis of the detector collimator aligned with the center of the waste, and there is a sufficient space between the detector and the waste container so that the entire container can be scanned. Read the entire page →
From page 155... ... The first area is a change in defective fuel conditions which would give rise to different release rates between nuclides. Detailed discussion on the variation of fission product release rate as a function of fuel failure condition has been presented previously in Section 3. Read the entire page →
From page 156... ... The major activation process involves the deposition of corrosion products on the fuel surfaces followed by their activation and subsequent release and transport to the radwaste system. There are also some important sources of Co-60 and Ni-63 in the core construction materials. Read the entire page →
From page 157... ... The plant and stream specific correlation factors can only be determined for a short operating duration because the correlation may vary from time to time depending on many factors discussed previously. Read the entire page →
From page 158... ... i.E. Cline, et al., "Direct Assay of Drummed Evaporator Bottoms, Dry-Active Waste and Filter Cartridges at the GINNA Nuclear Station", ANS Int. Read the entire page →

From page 143...

... Some major characteristics of the nuclides needed to be analyzed are listed in Table 7-2 Many of these nuclides do not emit measurable gamma rays in their decay and can be measured only through difficult and time-consuming radiochemical and nuclear counting processes, requiring techniques and equipment beyond the capability of most nuclear power plant on-site laboratories. Even in some reputable laboratories, significant differences in the results of some comparative analyses have been reported(2)

7. ASSAY OF RADIACTIVE WASTE Pages 143-158

7. ASSAY OF RADIACTIVE WASTE
Pages 143-158