5.1 Radium is one of the most radiotoxic elements. Its isotope of mass 226 is the most hazardous because of its long half-life. The isotopes 223 and 224, although not as hazardous, are of some concern in appraising the quality of water. 5.2 The alpha-particle-emitting isotopes of radium other than that of mass 226 may be determined by difference if radium-226 is measured separately, such as by Test Method D3454. Note that one finds 226Ra and 223Ra together in variable proportions (5, 6), but 224Ra does not normally occur with them. Thus, 223Ra often may be determined by simply subtracting the 226Ra content from the total: and if 226Ra and 223Ra are low, 224Ra may be determined directly. The determination of a single isotope in a mixture is less precise than if it occurred alone. 1.1 This test method covers the separation of dissolved radium from water for the purpose of measuring its radioactivity. Although all radium isotopes are separated, the test method is limited to alpha-particle-emitting isotopes by choice of radiation detector. The most important of these radioisotopes are 223Ra, 224Ra, and 226Ra. The lower limit of concentration to which this test method is applicable is 3.7 × 10-2 Bq/L (1 pCi/L). 1.2 This test method may be used for absolute measurements by calibrating with a suitable alpha-emitting radioisotope such as 226 Ra, or for relative methods by comparing measurements with each other. Mixtures of radium isotopes may be reported as equivalent 226Ra. Information is also provided from which the relative contributions of radium isotopes may be calculated. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Section 9.

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DOE Order 5480.11 and ANSI N13.30 require that internal dose assessments be made as part of the bioassay program for nuclear facility workers. For indirect bioassay of uranium workers, the uranium isotopes must be measured along with the total uranium in urine samples. The RMDA for each uranium isotope is 0.1 pCi/L. This method is applicable for measuring 235U and 238U at the RMDA. Because of extremely low mass concentration (because of the high specific activity), 234U cannot be measured without additional sample preconcentration. Note 2—Column chromatography separations and concentration of 234U using manual or flow-injection preconcentration followed by ICP-MS isotopic determination are described in Test Methods C1310 and C1345. These methods focus on environmental soil sample analysis, but with some development, may be applicable to digested urine samples. The 234U concentration can be calculated based on an enrichment gradient for workers in uranium enrichment plants, and internal dose assessments can be made. Note 3—Use of high resolution ICP-MS may also be used to obtain lower detection limits. 1.1 This test method covers the determination of the concentration of uranium-235 and uranium-238 in urine using Inductively Coupled Plasma-Mass Spectrometry. This test method can be used to support uranium facility bioassay programs. 1.2 This method detection limits for 235U and 238U are 6 ng/L. To meet the requirements of ANSI N13.30, the minimum detectable activity (MDA) of each radionuclide measured must be at least 0.1 pCi/L (0.0037 Bq/L). The MDA translates to 47 ng/L for 235U and 300 ng/L for 238U. Uranium– 234 cannot be determined at the MDA with this test method because of its low mass concentration level equivalent to 0.1 pCi/L. 1.3 The digestion and anion separation of urine may not be necessary when uranium concentrations of more than 100 ng/L are present. 1.4 Units—The values stated in picoCurie per liter units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1—Warning: The ICP-MS is a source of intense ultraviolet radiation from the radio frequency induced plasma. Protection from radio frequency radiation and UV radiation is provided by the instrument under normal operation.

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5.1 This test method is used to detect possible exposures to uranium isotopes from occupational operations that may result in elimination via the urinary tract.1.1 This test method is applicable to the determination of uranium in urine at levels of detection dependent on sample size, count time, detector background, and tracer yield. It is designed as a screening tool for detection of possible exposure of occupational workers.1.2 This test method is designed for 50 mL of urine. This test method does not address the sampling protocol or sample preservation methods associated with its use.1.3 Test Method C1844 offers an alternative method for the analysis of uranium in urine using ICP-MS detection.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. A specific precautionary statement is given in Section 9.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This standard practice defines a measure of heavy element atom percent fission from which the output of heat during irradiation can be estimated.5.2 This standard practice is restricted in use to samples where accurate pre-irradiation U and Pu isotopic analysis is available. This data should be available from the fuel manufacture.5.3 The contribution of 238U fast fission is not subject to measurement from isotopic analysis. For reactors in which the majority of fissions are caused by thermal neutrons, the contribution may be estimated from the fast fission factors, ε, found in each reactor design document.5.4 In post-irradiation isotopic analysis, take extreme care to avoid environmental uranium contamination of the sample. This is simplified by using sample sizes in which the amount of each uranium isotope is more than 1000 times the levels observed in a blank carried through the complete chemistry and mass spectrometry procedure employed.5.5 Take care to make sure that both the pre-irradiation and the post-irradiation samples analyzed are representative. In the pre-irradiation fuel, the 235U and 236U atom ratio content may vary from lot to lot. 236U is not found in naturally uranium in measurable quantity (<2 ppm of a u basis) but forms during irradiation and increases with each successive pass through the fuel cycle. In the post-irradiation examination of a large fuel element, the atom percent fission normally varies radially and axially. Radial and axial profiles of atom percent fission can be determined by analyzing samples obtained from along the radius or axis of the fuel element. An average value of atom percent fission can be obtained by totally dissolving the fuel to be averaged, and then mixing and analyzing an aliquot of the resultant solution.5.6 The burnup of an irradiated nuclear fuel can be determined from the amount of a fission product formed during irradiation. Among the fission products, 148Nd has the following properties to recommend it as an ideal burnup indicator: (1) It is not volatile. (2) It does not migrate in solid fuels below their recrystallization temperature. (3) It has no volatile precursors. (4) It is nonradioactive and requires no decay corrections. (5) It has a low destruction cross section. (6) Formation of 148Nd from adjacent mass chains can be corrected for. (7) It has adequate emission characteristics for mass analysis. (8) Its fission yield is nearly equivalent for 235U and 239Pu. (9) Its fission yield is essentially independent of neutron energy (11). (10) It has a shielded isotope, 142Nd, which can be used for correcting natural neodymium contamination. (11) It is an atypical constituent of unirradiated fuel.1.1 A sample of spent nuclear fuel is analyzed to determine the quantity and atomic ratios of uranium and plutonium isotopes, neodymium isotopes, and selected gamma-emitting nuclides (137Cs, 134Cs, 154Eu, 106Ru, and 241Am). Fuel burnup is calculated from the 148Nd-to-fuel ratio as described in this method, which uses an effective 148Nd fission yield calculated from the fission yields of 148Nd for each of the fissioning isotopes weighted according to their contribution to fission as obtained from this method. The burnup value determined in this way requires that values be assumed for certain reactor-dependent properties called for in the calculations (1, 2).21.2 Error associated with the calculated burnup values is discussed in the context of contributions from random and potential systematic error sources associated with the measurements and from uncertainty in the assumed reactor-dependent variables. Uncertainties from the needed assumptions are shown to be larger than uncertainties from the isotopic measurements, with the largest effect arising from the value of the fast fission factor. Using this factor will provide the most consistent burnup value between calculated changes in heavy element isotopic composition.1.3 This standard practice contains explanatory notes that are not part of the mandatory portion of the standard.1.4 The values stated in SI units are to be regarded as the standard. Mathematical equivalents are given in parentheses.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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5.1 This test method is used to analyze soil for alpha-emitting uranium isotopes. It can be used to establish baseline uranium levels and to monitor depositions from nuclear facilities.1.1 This test method covers the determination of alpha-emitting uranium isotopes in soil. This test method describes one acceptable approach to the determination of uranium isotopes in soil.21.2 The test method is designed to analyze 10 g of soil. This test method may not be able to completely dissolve all forms of uranium in the soil matrix. Studies have indicated that the use of hydrofluoric acid to dissolve soil has resulted in lower values than results using total dissolution by fusion.1.3 The lower limit of detection is dependent on count time, sample size, detector, background, and tracer yield. The chemical yield averaged 78 % in a single laboratory evaluation, and 66 % in an interlaboratory collaborative study.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 11.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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