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[en] With a view to examining the dependence of mass distribution on neutron number for a fixed Z of fissioning nucleus, mass distribution in the neutron induced fission of ²³²U(lightest uranium isotope investigated so far) has been determined for the first time. The low energy neutron fission of the other two uranium isotopes ²³³U and ²³⁵U is known to be predominantly asymmetric. The mass distribution of ²³²U is also asymmetric but with a distinct third peak in the symmetric mass region in contrast to ²³³U and ²³⁵U mass distribution. The appearance of the symmetric peak seems to be a strong function of neutron number of the fissioning nucleus. The characteristics of mass distribution for neutron induced fission of ²³²U have been found to be in conformity with systematics of the outer barrier heights for asymmetric and symmetric saddle point configurations. The results of the radiochemical studies on the mass distribution in the neutron induced fission of ²³²U are discussed. (author)

[en] A relatively rapid, economic and robust procedure is described for the radiometric analysis of uranium in phosphate rock and phosphogypsum. The analysis is performed by alpha spectroscopy after pre-concentration and separation of uranium by liquid-extraction using tributyl-phosphate (30% TBP in dodecan) and finally its electrodeposition on stainless steel discs. The method has been successfully applied to 0.1 g samples of phosphate rock and phosphogypsum resulting in high-quality spectra for measurement times ≥15 h. The main advantage of the procedure is the use of tracer solution (²³²U) that allows reliable measurements and evaluation of the separation procedure. The separation efficiency of the proposed method has been estimated to be (75 ± 20)%. (author)

[en] The post-neutron absolute mass yields of 35 products from 23 mass chains for ²³²U(nsub(th),f) have been determined by γ-ray spectroscopy. The resulting mass distribution for ²³²U is compared with the corresponding existing data on ²³³U and ²³⁵U. (author)

[en] The Radiochemical Processing Plant (RPP) at ORNL has served as the national repository and distribution center for ²³³U for > 20 years. Several hundred kilograms of uranium, containing approximately 90 to 98% ²³³U, are stored there in the form of metal, oxides, and nitrate solutions. All of these uranium materials contain small, but significant, concentrations of ²³²U, ranging from 2 to 225 ppm. Most of the radioactivity associated with the ²³³U comes from the decay daughters of ²³²U (74-year half-life). The ²⁵²Cf Industrial Sales/Loan Program involves loans of ²⁵²Cf neutron sources to agencies of the US Government and sales of ²⁵²Cf as the bulk oxide and as palladium-californium alloy pellets and wires. The program has been operated since 1968 in temporary facilities at the Savannah River Laboratory (SRL). The obsolete hot-cell facilities at SRL are now being decommissioned, and the program activities are being transferred to ORNL's Californium Facility in Bldg. 7930, which is managed by the staff of the Transuranium Processing Plant

[en] A method for as certain the activity by alpha spectroscopy with semiconductor detectors, of a solution of 232U is presented. It consists of the comparison with a 233U solution activity previously measured in a gridded ionization chamber of 2π geometry. The total measurement uncertainty is about + - 0,02. (Author) 9 refs

[en] A single mode pulsed fiber laser was used to remove fixed contamination from stainless steel substrate by ablation. Samples were simulated by electro-deposition technique with "2"3"2U as the test contaminant. Laser power, repetition rate, laser beam scanning speed and number of passes were optimised to obtain the desired ablation depth in the substrate. Ablation depth varying between few microns to few hundreds of microns could be achieved through careful control of these processing parameters. The absence of any activity in laser treated samples provided experimental signature of the efficacy of the laser assisted removal of fixed contamination. (author)

[en] The present paper reports the baseline monitoring data of these workers for U(nat.) using solid extraction chromatography technique. ²³²U Working standard of 21.6 mBq/ml was prepared by diluting NPL standard (103.5± 1.0 Bq/g,) with 3M HNO₃. 1 g UTEVA resin of 100-150 μm particle size was used for separation of U from urine. The urinary excretion rate observed for the individual in the present study can be treated as the existing level of U in urine for TDP workers. The values observed need to be subtracted from subsequent results obtained during future routine monitoring programmes in the facility to identify potential intakes, if any, before assignment of internal dose

[en] The post-neutron absolute mass yields of 35 products from 23 mass chains for /sup 232/U(n/sub th/,f) have been determined by γ-ray spectroscopy. The resulting mass distribution for /sup 232/U is compared with the corresponding existing data on /sup 233/U and /sup 235/U

[en] Internal exposure monitoring for alpha emitting radionuclides is carried out by bioassay samples analysis. For occupational radiation workers handling uranium in reprocessing or fuel fabrication facilities, there exists a possibility of internal exposure and urine assay is the preferred method for monitoring such exposure. Estimation of lower concentration of uranium at mBq level by alpha spectrometry requires preconcentration and its separation from large volume of urine sample. For this purpose, urine samples collected from non radiation workers were spiked with ²³²U tracer at mBq level to estimate the chemical yield. Uranium in urine sample was pre-concentrated by calcium phosphate coprecipitation and separated by extraction chromatography resin U/TEVA. In this resin extractant was DAAP (Diamylamylphosphonate) supported on inert Amberlite XAD-7 support material. After co-precipitation, precipitate was centrifuged and dissolved in 10 ml of 1M Al(NO₃)₃ prepared in 3M HNO₃. The sample thus prepared was loaded on extraction chromatography resin, pre-conditioned with 10 ml of 3M HNO₃. Column was washed with 10 ml of 3M HNO₃. Column was again rinsed with 5 ml of 9M HCl followed by 20 ml of 0.05 M oxalic acid prepared in 5M HCl to remove interference due to Th and Np if present in the sample. Uranium was eluted from U/TEVA column with 15 ml of 0.01M HCl. The eluted uranium fraction was electrodeposited on stainless steel planchet and counted by alpha spectrometry for 360000 sec. Approximate analysis time involved from sample loading to stripping is 2 hours when compared with the time involved of 3.5 hours by conventional ion exchange method. Seven urine samples from non radiation worker were radio chemically analyzed by this technique and the radiochemical yield was found in the range of 69-91 %. Efficacy of this method against conventional anion exchange technique earlier standardized at this laboratory is also being highlighted. Minimum detectable activity (MDA) for uranium estimation for 360000 sec counting time at an average percentage recovery of 78 ± 8 works out to 0.24 mBq/d. This paper presents the analytical results obtained during the standardization of the method using U/TEVA chromatographic resin with special emphasis on chemical recovery and time involved. (author)