Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: W. Boyce x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

This paper describes development work to prepare a method to measure absolute239Pu content and Pu-isotopics by ICP-MS in acidified Hanford DOE-site samples which are very high in90Sr,99Tc, and137Cs radioactivity and which are frequently high in organic carbon content. Samples with very large90Sr and137Cs contents have historically been difficult to analyze for Pu content by each of three alpha-counting techniques in use at SRS, and analysis by ICP-MS in these samples is complicated by the high organics content. We report an ion exchange chemical preparation to obtain fraction of Pu that does not contain any fission product contribution and no interfering organics to allow measure of absolute239Pu and of239Pu through241Pu isotopics by ICP-MS. The method uses a242Pu spike to measure Pu recovery and is demonstrated in this paper with three distinct commercially available resins and with over 300 samples. Measured absolute239Pu contents in sixty-three spiked/unspiked duplicates have agreed within 15% precision. Overall242Pu recoveries were near 90% with 25% precision. Comparisons of absolute239Pu contents measured directly on three samples agreed within the quoted 25% uncertainty.

Restricted access

Abstract  

We have developed a chemical separation technique that allows the radiochemical determination of the californium -decay content in Department of Energy (DOE) high level wastes from the Hanford and Savannah River sites. The chemical separation technique uses a series of column extraction chromatography steps that use Eichrom Industries' lanthanide and actinide +3 oxidation state selective Ln-resin® and the transuranic selective +4 oxidation state TRU-resin® to obtain intermediate product phases in dilute nitric acid. The technique has been demonstrated on three types of authentic DOE high and low level waste samples. We obtain discrimination from Pu -activity by a factor of over 200 and from 244Cm -activity by a factor approaching 1700. Californium recoveries are measured by addition of a 249Cf spike and are in the range of 50% to 90% in the synthetic samples and are in the range of 1.4% to 48% for the authentic DOE waste samples.

Restricted access

Abstract  

We report the first observation of confirmed 79Se activity in Savannah River Site high level fission product waste. 79Se was measured after a seven step chemical treatment to remove interfering activity from 137Cs, 90Sr, and plutonium at levels 105 times higher than the observed 79Se content and to remove 99Tc at levels 300 times higher than observed 79Se. 79Se was measured by liquid scintillation -decay counting after specific tests to eliminate uncertainties from possible contributions from 99Tc, 147Pm, 151Sm, 93Zr, or 241Pu, whose -decay spectra could appear similar to that of 79Se, and whose content would be expected at levels near or greater than 79Se.

Restricted access

Abstract  

Savannah River Site (SRS) is immobilizing the radioactive, high-level waste sludge in Tank 51 into a borosilicate glass for disposal in a geologic repository. A requirement for repository aceeptance is that SRS report the concentrations of certain fission product and actinide radionuclides in the glass. This paper presents measurements of many of these concentrations in both Tank 51 sludge and the final glass. The radionuclides were measured by inductively coupled plasma mass spectrometry and α, β, and γ counting methods. Examples of the radionuclides are90Sr,137Cs,238U and,239Pu. Concentrations in the glass are 3.1 times lower due to dilution of the sludge with a nonradio-active glass forming frit in the vitrification process. Results also indicated that in both the sludge and glass the relative concentrations of the long lived fission products insoluble in caustic are in proportion to their yields from the fission of235U waste in the SRS reactors. This allowed the calculation of a fission yield scaling factor. This factor in addition to the sludge dilution factor can be used to estimate concentrations of waste acceptance radionuclides that cannot be measured in the glass. Examples of these radionuclides are79Se,93Zr, and107Pd.

Restricted access

Abstract  

This paper describes development work to obtain a product phase of 151Sm pure of any other radioactive species so that it can be determined in US Department of Energy high level liquid waste and low level solid waste by liquid scintillation b-spectroscopy. The technique provides separation from mCi/ml levels of 137Cs, Pu a- and 241Pu b-decay activity, and 90Sr/90Y activity. The separation technique is also demonstrated to be useful for the determination of 147Pm.

Restricted access