5.1 Segmented gamma-ray scanning provides a nondestructive means of measuring the nuclide content of scrap and waste where the specific nature of the matrix and the chemical form and relationship between the nuclide and matrix may be unknown.5.2 The procedure can serve as a diagnostic tool that provides a vertical profile of transmission and nuclide concentration within the item.5.3 Item preparation is generally limited to good waste/scrap segregation practices that produce relatively homogeneous items that are required for any successful waste/inventory management and assay scheme, regardless of the measurement method used. Also, process knowledge should be used, when available, as part of a waste management program to complement information on item parameters, container properties, and the appropriateness of calibration factors.5.4 To obtain the lowest detection levels, a two-pass assay should be used. The two-pass assay also reduces problems related to potential interferences between transmission peaks and assay peaks. For items with higher activities, a single-pass assay may be used to increase throughput.1.1 This test method covers the transmission-corrected nondestructive assay (NDA) of gamma-ray emitting special nuclear materials (SNMs), most commonly 235U, 239Pu, and 241Am, in low-density scrap or waste, packaged in cylindrical containers. The method can also be applied to NDA of other gamma-emitting nuclides including fission products. High-resolution gamma-ray spectroscopy is used to detect and measure the nuclides of interest and to measure and correct for gamma-ray attenuation in a series of horizontal segments (collimated gamma detector views) of the container. Corrections are also made for counting losses occasioned by signal processing limitations (1-3).21.2 There are currently several systems in use or under development for determining the attenuation corrections for NDA of radioisotopic materials (4-8). A related technique, tomographic gamma-ray scanning (TGS), is not included in this test method (9, 10, 11).1.2.1 This test method will cover two implementations of the Segmented Gamma Scanning (SGS) procedure: (1) Isotope Specific (Mass) Calibration, the original SGS procedure, uses standards of known radionuclide masses to determine detector response in a mass versus corrected count rate calibration that applies only to those specific radionuclides for which it is calibrated, and (2) Efficiency Curve Calibration, an alternative method, typically uses non-SNM radionuclide sources to determine system detection efficiency vs. gamma energy and thereby calibrate for all gamma-emitting radionuclides of interest (12).1.2.1.1 Efficiency Curve Calibration, over the energy range for which the efficiency is defined, has the advantage of providing calibration for many gamma-emitting nuclides for which half-life and gamma emission intensity data are available.1.3 The assay technique may be applicable to loadings up to several hundred grams of nuclide in a 208-L [55-gal] drum, with more restricted ranges to be applicable depending on specific packaging and counting equipment considerations.1.4 Measured transmission values must be available for use in calculation of segment-specific attenuation corrections at the energies of analysis.1.5 A related method, SGS with calculated correction factors based on item content and density, is not included in this standard.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.7 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 10.1.8 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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4.1 This practice is useful for preparing extracts from fire debris for later analysis by gas chromatography mass spectrometry.4.2 This is a very sensitive separation procedure, capable of isolating quantities smaller than 1/10 μL of ignitable liquid residue from a sample.1.1 This practice describes the procedure for separation of small quantities of ignitable liquid residues from samples of fire debris using an adsorbent material to extract the residue from the static headspace above the sample, then eluting the adsorbent with a solvent.1.2 While this practice is suitable for successfully extracting ignitable liquid residues over the entire range of concentration, the headspace concentration methods are best used when a high level of sensitivity is required due to a very low concentration of ignitable liquid residues in the sample.1.2.1 Unlike other methods of separation and concentration, this practice is essentially nondestructive.1.3 Alternate separation and concentration procedures are listed in the referenced documents (see Practices E1386, E1388, E1413, and E2154).1.4 This practice does not replace knowledge, skill, ability, experience, education, or training and should be used in conjunction with professional judgment.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 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.1.7 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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This specification describes an approach for testing the fire resistance of concrete tunnel linings, fire-resistive materials, and structural tunnel members. It requires testing of both horizontal and vertical orientations and is limited to concrete mix design and fire-resistive materials, as well as the potential impact of environmental exposures (optional). A minimum of one fire test is required for each assembly, configuration, and orientation. For cases where the concrete mix design is intended to address the fire load independent of fire-resistive materials, the Spalling Test is applicable. For cases where standard or general concrete design mix is intended and protected by fire-resistive materials, the Fire-Resistive Material Test is applicable. For cases where both the concrete design mix and fire-resistive materials are combined to address the fire load, both test criteria are applicable but can be accomplished with one fire test for each assembly, configuration, and orientation. The test methods covered by this specification are used to determine the performance of tunnel construction elements with respect to exposure to a standard time-temperature fire test. The tests include surface burning test, environmental tests (optional: ground water test, road salt test, tunnel interior surface washing, spalling test, fire-resistive material test), and fire-resistive joint test.This specification also covers the requirements for flame spread, control of fire tests for fire resistive materials, test specimen for fire resistive materials, conduct of test, overall conditions of acceptance, report, and precision and bias.1.1 This specification is applicable to the fire resistance of concrete tunnel linings, fire-resistive materials, and structural tunnel members.1.2 Concrete mix design, tunnel linings, and passive fire protection methods are specific to each tunnel project. Therefore results of the spalling test are only valid for the specific materials and systems employed during each test, notwithstanding maximum and minimum limitations.1.3 Tunnels are potentially exposed to ground water, even those passing through elevated terrain, such as mountains, road salt, and maintenance surface washing. Consideration shall be given to potential adverse effects that result, such as material degradation due to these exposures.1.4 Movement joints shall be considered and their impact on the overall fire resistance shall be assessed by testing. Tests shall be conducted as a system.1.5 This specification does not address mechanical attachment methods for equipment due to the vast variety of possible methods and loads. However, consideration shall be given to methods that appreciably affect the concrete temperature during the heating conditions. Consideration shall be given to a second test conducted with the attachment to evaluate the effect. The attachment test shall include the largest diameter anchor, the deepest installed anchor, and the largest load applied to the anchor. This requirement results in a single anchor being tested or multiple anchors being tested. If multiple anchors are required to be tested, then each shall be tested under its maximum load.1.6 This specification requires testing of both horizontal and vertical orientations. For fire-resistive materials, it is generally accepted that the horizontal orientation represents the worst case test scenario.1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.1.8 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not, by itself, incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.1.9 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.1.10 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.1.11 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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4.1 This classification is intended to provide information on currently available commercial seals as a guide in their selection for specific applications. This classification is not intended to inhibit the innovation or development of new types of seals.1.1 This classification covers a specific category of commercially available passive seals.1.2 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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4.1 General—Passive groundwater sampling has increased use since the polyethylene diffusion bag sampler was first introduced (5). As defined above, different types of passive samplers are now available with different functions and usages. The Interstate Technology Regulatory Council (ITRC) has provided several technical and regulatory documents on the use of passive groundwater sampling methods (1, 5-7). Collectively, these documents have provided information and references on the technical basis for their use, comparison of sampling results with more traditional sampling methods, descriptions of their proper use, limitations, and a survey of their acceptance and use by responding state regulators. However, the ITRC documents are older and do not include more recent assessments and publications. This Standard seeks to provide newer information on current practice and implementation of passive groundwater sampling techniques.4.1.1 Because of the large number of passive samplers that have been developed over the years for various types of environmental sampling, it is beyond the scope of this standard to discuss separately each of the methods that could or can be used to sample groundwater. Extensive literature reviews on diffusion- and accumulation-passive samplers can be found in the scientific literature (that is, 3, 8-14). These reviews provide information on a wide variety of passive sampling devices for use in air, soil vapor, and water. A review paper on the use of diffusion and accumulation-type passive samplers specifically for sampling volatile organic compounds (VOCs) in groundwater (15) includes information on other passive samplers that are not included in the ITRC documents (1, 7) and discusses their use with respect to measuring mass flux.4.2 Use—Passive samplers are deployed at a pre-determined depth, or depths, within a well for a minimum or pre-determined period of time. They should remain submerged at the target depth for their entire deployment period. All of the passive technologies described in this document rely on the sampling device being exposed to the groundwater during deployment and the continuous flushing of the open or screened interval of the well by ambient groundwater flow ((4), (5-7), 16) to produce water quality conditions in the well bore that effectively mimic those conditions in the aquifer adjacent to the screen or open interval. For samplers that require the establishment of equilibrium, it is important that the equilibration period be long enough to allow the well to recover from any disturbance caused by placing the sampler in the well and to prevent, or reduce, losses of analytes from the water sample by sampler materials due to sorption. For kinetic accumulation samplers (used as kinetic samplers), it is important that the deployment time is long enough that quantitative uptake can occur but not so long that uptake is no longer in the linear portion of the uptake curve (that is, has become curvilinear).4.2.1 As with all types of groundwater sampling methods, the appropriate use of passive methods assumes that the well has been properly located (laterally and vertically), designed, constructed, and was adequately developed (as described in Guide D5521/D5521M) and maintained (as described in Practices D5092/D5092M and D6725/D6725M, or Guide D6724/D6724M). These measures are necessary so that the well is in hydraulic communication with the aquifer.4.2.2 Each type of passive sampler has its own attributes and limitations, and thus data-quality objectives (DQOs) for the site should be reviewed prior to selecting a device. For wells in low-permeability formations, diffusive flux may become more important than advective flow in maintaining aquifer-quality water in the well.4.3 Advantages—While passive methods are not expected to replace conventional pumped sampling in all situations, they often offer a faster alternative “tool” for sampling groundwater monitoring wells because purging is eliminated from the pre-sampling procedure. Other advantages include that these samplers can be used in most wells and typically have no depth limitation. These samplers are either disposable or dedicated to a well. This eliminates or reduces the need for decontamination. Passive samplers typically reduce the logistics associated with sampling and are especially useful at sites where it is difficult to bring larger equipment (such as pumps and compressors) to the well location.4.3.1 Passive groundwater sampling techniques typically provide a lower “per-sample” cost than conventional pumped sampling methods (17-26). This is primarily because the labor associated with collecting a sample is substantially reduced and waste handling and disposal is substantially reduced. Eliminating handling and disposal of purge water is an environmental benefit and advantage.4.3.2 If there is interest in identifying contaminant stratification within the well, multiple passive samplers can be used to characterize vertical contaminant distribution with depth. Baffles or packers can be used to segregate the sampling zones and often provide better characterization of each zone. Profiling contamination with depth in a well can be informative when trying to decide where to place a single passive sampler within the well screen for long-term monitoring; placing a sampler at the mid-point of the screen may not yield a sample with the highest contaminant concentrations or one that agrees best with previous low-flow concentrations (for example, 26).4.4 Disadvantages—As with any groundwater sampling method, rapid or rigorous deployment of the sampler(s) can increase turbidity in the well. For passive groundwater samplers, this can be reduced or eliminated if the equilibration time is long enough to allow the return of the natural ambient turbidity in the well. In many cases, passive samplers are deployed at the end of a sampling event and left in the well until the next scheduled sampling event; this practice provides more than enough time for equilibration to occur. Some methods require dedicated equipment purchase which may increase the cost for the initial sampling event in order to obtain the overall cost advantage.4.5 Limitations—There are three primary limitations with passive samplers: analyte capability, sample volume, and physical size with respect to well diameter. For the diffusion and accumulation samplers, the membrane and or sorbent, respectively, determine the analyte capability of the sampler. In contrast, passive-grab samplers collect whole water samples and can be used for any analyte, subject to sample volume and physical size limitations.4.5.1 Analyte capability is often unique to individual passive samplers. In the case of diffusion-based passive samplers, the user should verify that the membrane is suitable for the analytes to be tested. ITRC (5-7) describes the analyte capability of diffusion-bases passive samplers. Two or more individual types of passive samplers can be used simultaneously to sample for a broader spectrum of analyte types.4.5.2 Passive-grab and passive-diffusion samplers collect a finite sample volume. Total sampler volume may limit the number and type of analytes that can be practically collected. Additional samplers or larger volume samplers may be available and can be used to meet the volume requirements. Also, because laboratories typically use only a small portion of the sample collected, it may be possible to provide the laboratory with a smaller sample volume. Table X1.1 provides suggested minimum volumes for several analyte classes. The laboratory should be consulted to confirm adequate sample volume during the method selection process.4.5.3 Regarding physical sizes of the sampler(s), the diameter of the sampler or combination of samplers must be able to fit in the well or multi-level sampler.NOTE 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This standard provides guidance and information on passive sampling techniques for collecting groundwater from monitoring wells. Passive groundwater samplers are able to acquire a sample from the screen interval in a well, without the active transport associated with a pump or purge technique (1).2 Passive groundwater sampling is a type of no-purge groundwater sampling method where the samplers are left in the well for a predetermined period of time prior to collecting the sample.1.2 Methods for sampling monitoring wells include low-flow purging and sampling methods, traditional well-volume purging and sampling methods, post-purge grab sampling methods (for example, using a bailer), passive no-purge sampling methods, and active no-purge sampling methods such as using a bailer to collect a sample without purging the well. This guide focuses on passive no-purge sampling methodologies for collecting groundwater samples. These methodologies include the use of diffusion samplers, accumulation samplers, and passive-grab samplers. This guide provides information on the use, advantages, disadvantages, and limitations of each of these passive sampling technologies.1.3 ASTM Standard D653 provides standard terminology relevant to soil, rock, and fluids contained in them. ASTM Standard D4448 provides a standard guide to sampling groundwater wells, and ASTM Standards D5903 and D6089 provide guides for planning and documenting a sampling event. Groundwater samples may require preservation (Guide D6517), filtration (Guide D6564/D6564M), and measures to pack and ship samples (Guide D6911). Standard D7069 provides guidance on the quality control and quality assurance of sampling events. ASTM Standard D5092/D5092M provides standard practice for the design and installation of groundwater monitoring wells, ASTM Standard D5521/D5521M provides a standard guide for developing groundwater monitoring wells in granular aquifers, and D6452 provides a standard guide for purging methods used in groundwater quality investigations. Consult ASTM Standard D6724/D6724M for a guide on the installation of direct-push groundwater monitoring wells and ASTM Standard D6725/D6725M for a guide on the installation of direct-push groundwater monitoring wells with pre-pack screens.1.4 The values stated in SI Units are to be regarded as the standard. Values in inches (such as with well diameters) are given in parentheses, and are provided for information. Use of units other than SI shall not be regarded as nonconforming with this standard.1.5 This guide provides information on passive groundwater sampling in general and also provides a series of considerations when selecting a passive groundwater sampling method. However, it does not recommend a specific course of action, and not all aspects of this guide may be applicable in all field situations. This document cannot replace education or experience and should be used in conjunction with professional judgment. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.6 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.1.7 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 The following methods assist in demonstrating regulatory compliance in such areas as safeguards (Special Nuclear Material), inventory control, criticality control, decontamination and decommissioning, waste disposal, holdup and shipping.5.2 This guide can apply to the assay of radionuclides in containers, whose gamma-ray absorption properties can be measured or estimated, for which representative certified standards are not available. It can be applied to in situ measurements, measurement stations, or to laboratory measurements.5.3 Some of the modeling techniques described in the guide are suitable for the measurement of fall-out or natural radioactivity homogenously distributed in soil.5.4 Source-based efficiency calibrations for laboratory geometries may suffer from inaccuracies due to gamma rays being detected in true coincidence. Modeling can be an advantage since it is unaffected by true coincidence summing effects.1.1 This guide addresses the use of models with passive gamma-ray measurement systems. Mathematical models based on physical principles can be used to assist in calibration of gamma-ray measurement systems and in analysis of measurement data. Some nondestructive assay (NDA) measurement programs involve the assay of a wide variety of item geometries and matrix combinations for which the development of physical standards are not practical. In these situations, modeling may provide a cost-effective means of meeting user’s data quality objectives.1.2 A scientific knowledge of radiation sources and detectors, calibration procedures, geometry and error analysis is needed for users of this standard. This guide assumes that the user has, at a minimum, a basic understanding of these principles and good NDA practices (see Guide C1592/C1592M), as defined for an NDA professional in Guide C1490. The user of this standard must have at least a basic understanding of the software used for modeling. Instructions or further training on the use of such software is beyond the scope of this standard.1.3 The focus of this guide is the use of response models for high-purity germanium (HPGe) detector systems for the passive gamma-ray assay of items. Many of the models described in this guide may also be applied to the use of detectors with different resolutions, such as sodium iodide or lanthanum halide. In such cases, an NDA professional should determine the applicability of sections of this guide to the specific application.1.4 Techniques discussed in this guide are applicable to modeling a variety of radioactive material including contaminated fields, walls, containers and process equipment.1.5 This guide does not purport to discuss modeling for “infinite plane” in situ measurements. This discussion is best covered in ANSI N42.28.1.6 This guide does not purport to address the physical concerns of how to make or set up equipment for in situ measurements but only how to select the model for which the in situ measurement data is analyzed.1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.8 The values stated in inch-pound 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.1.9 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.

定价： 590元 / 折扣价： 502 元 加购物车

1.1 This test method covers personal or area measurements of formaldehyde in indoor air in the range from 0.01 to 17 mg/m (0.008 to 14 ppm v/v). Formaldehyde is collected in a passive diffusion sampler, and analyzed by a colorimetric method using 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH). The recommended sampling time is 15 min to 24 h. 1.2 The lower quantification limit of the MBTH test method is 0.03 [mu]g of formaldehyde per millilitre of absorbing solution used. A formaldehyde concentration of 0.01 mg/m (0.008 ppm v/v) can be determined in indoor air, based on using an aliquot of 5 mL of absorbing solution in the prescribed sampler for a period of 24 h and observing a minimum difference of 0.05 absorbance units from the blank when using spectrophotometer cells of path length 1 cm. 1.3 Water soluble aliphatic aldehydes give a significant positive interference (1, 2) nearly equal to formaldehyde on a molar basis. Further information on estimating potential and actual interferences from aliphatic aldehydes may be found in 6.2 and 10.1.7. Most other compounds which react to produce colored products are not gaseous or water soluble and, consequently, should not interfere. 1.4 The values stated in SI units are to be regarded as the 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. Specific precautionary statements are given in Notes 1 and 2.

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5.1 This test method is useful for determining the plutonium content of scrap and waste in containers ranging from small cans with volumes of the order of a mL to crates and boxes of several thousand liters in volume. A common application would be to 208-L (55-gal) drums. Total Pu content ranges from 10 mg to 6 kg (1). The upper limit may be restricted depending on specific matrix, calibration material, criticality safety, or counting equipment considerations. 5.2 This test method is applicable for U.S. Department of Energy shipper/receiver confirmatory measurements (9), nuclear material diversion detection, and International Atomic Energy Agency attributes measurements (10). 5.3 This test method should be used in conjunction with a scrap and waste management plan that segregates scrap and waste assay items into material categories according to some or all of the following criteria: bulk density, the chemical forms of the plutonium and the matrix, americium to plutonium isotopic ratio, and hydrogen content. Packaging for each category should be uniform with respect to size, shape, and composition of the container. Each material category might require calibration standards and may have different Pu mass limits. 5.4 Bias in passive neutron coincidence measurements is related to item size and density, the homogeneity and composition of the matrix, and the quantity and distribution of the nuclear material. The precision of the measurement results is related to the quantity of nuclear material, the (α,n) reaction rate, and the count time of the measurement. 5.4.1 For both benign matrix and matrix specific measurements, the method assumes the calibration reference materials match the items to be measured with respect to the homogeneity and composition of the matrix, the neutron moderator and absorber content, and the quantity of nuclear material, to the extent they affect the measurement. 5.4.2 Measurements of smaller containers containing scrap and waste are generally more accurate than measurements of larger items. 5.4.3 It is recommended that where feasible measurements be made on items with homogeneous contents. Heterogeneity in the distribution of nuclear material, neutron moderators, and neutron absorbers have the potential to cause biased results. 5.5 The coincident neutron production rates measured by this test method are related to the mass of the even number isotopes of plutonium. If the relative abundances of these isotopes are not accurately known, biases in the total Pu assay value will result. 5.6 Typical count times are in the range of 300 to 3600 s. 5.7 Reliable results from the application of this method require training of the personnel who package the scrap and waste prior to measurement and of personnel who perform the measurements. Training guidance is available from ANSI 15.20, Guides C986, C1009, C1068, and C1490. 1.1 This test method describes the nondestructive assay of scrap or waste for plutonium content using passive thermal-neutron coincidence counting. This test method provides rapid results and can be applied to a variety of carefully sorted materials in containers as large as several thousand liters in volume. The test method applies to measurements of 238Pu,  240Pu, and 242Pu and has been used to assay items whose total plutonium content ranges from 10 mg to 6 kg (1) .2 1.2 This test method requires knowledge of the relative abundances of the Pu isotopes to determine the total Pu mass (Test Method C1030). 1.3 This test method may not be applicable to the assay of scrap or waste containing other spontaneously fissioning nuclides. 1.3.1 This test method may give biased results for measurements of containers that include large amounts of hydrogenous materials. 1.3.2 The techniques described in this test method have been applied to materials other than scrap and waste (2, 3). 1.4 This test method assumes the use of shift-register-based coincidence technology (4). 1.5 Several other techniques that are often encountered in association with passive neutron coincidence counting exist. These include neutron multiplicity counting (5, 6, Test Method C1500), add-a-source analysis for matrix correction (7), flux probes also for matrix compensation, cosmic-ray rejection (8) to improve precision close to the detection limit, and alternative data collection electronics such as list mode data acquisition. Passive neutron coincidence counting may also be combined with certain active interrogation schemes as in Test Methods C1316 and C1493. Discussions of these established techniques are not included in this method. 1.6 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. 1.7 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 test method is useful for quantifying fissile (for example, 233U, 235U,  239Pu and 241Pu) and spontaneously-fissioning nuclei (for example, 238Pu, 240Pu,  242Pu, 244Cm,248Cm, and  252Cf) in waste and scrap drums. Total elemental mass of the radioactive materials can be calculated if the relative abundances of each radionuclide are known.5.1.1 Typically, this test method is used to measure one fissile isotope (for example, 235U or  239Pu).5.2 This test method can be used to segregate low level and transuranic waste at the 100 nCi/g concentration level currently required to meet the DOE Waste Isolation Pilot Plant (WIPP) waste acceptance criterion (5, 8, 9).5.3 This test method can be used for waste characterization to demonstrate compliance with the radioactivity levels specified in waste, disposal, and environmental regulations (See NRC regulatory guides, DOE Order 435.1, 10 CFR Part 71, 40 CFR Part 191, and DOE /WIPP-069).5.3.1 In the active mode, the DDT system can measure the 235U content in the range from <0.02 to >100 g and the 239Pu content, nominally between <0.01 and >20 g.5.3.2 In the passive mode, the DDT system is capable of assaying spontaneously-fissioning nuclei, over a nominal range from 0.05 to 15 g of 240Pu, or equivalent (5, 10, 11, 12, 13).5.4 This test method should be used in conjunction with a waste management plan that segregates the contents of assay items into material categories according to some or all of the following criteria: bulk density of the waste, chemical forms of the plutonium or uranium and matrix, (α, n) neutron intensity, hydrogen (moderator) and absorber content, thickness of fissile mass(es), and the assay item container size and composition. Each matrix may require a different set of calibration standards and may have different mass calibration limits. The effect on the quality of the assay (that is, minimizing precision and bias) can significantly depend on the degree of adherence to this waste management plan.5.5 The bias of the measurement results is related to the fill height, the homogeneity and composition of the matrix, the quantity and distribution of the nuclear material, and the item size. The precision of the measurement results is related to the quantity of the nuclear material, the background, and the count time of the measurement.5.5.1 For both matrix-specific and wide-range calibrations, this test method assumes the calibration material matches the items to be measured with respect to homogeneity and composition of the matrix, the neutron moderator and absorber content, and the quantity, distribution, and form of nuclear material, to the extent they affect the measurement.5.5.2 The algorithms for this test method assume homogeneity. Heterogeneity in the distribution of nuclear material, neutron moderators, and neutron absorbers has the potential to cause biased results (14).5.5.3 This test method assumes that the distribution of the contributing radioisotopes is uniform throughout the container and that lumps of nuclear material are not present.5.6 Reliable results from the application of this test method require waste to be packaged so the conditions of Section 5.5 can be met. In some cases, site-specific requirements will dictate the packaging requirements with possible detrimental effects to the measurement results.5.7 Both the active mode and the passive mode provide assay values for plutonium. During the calibration process, the operator should determine the applicable mass ranges for both modes of operation.1.1 This test method covers a system that performs nondestructive assay (NDA) of uranium or plutonium, or both, using the active, differential die-away technique (DDT), and passive neutron coincidence counting. Results from the active and passive measurements are combined to determine the total amount of fissile and spontaneously-fissioning material in drums of scrap or waste. Corrections are made to the measurements for the effects of neutron moderation and absorption, assuming that the effects are averaged over the volume of the drum and that no significant lumps of nuclear material are present. These systems are most widely used to assay low-level and transuranic waste, but may also be used for the measurement of scrap materials. The examples given within this test method are specific to the second-generation Los Alamos National Laboratory (LANL) passive-active neutron assay system.1.1.1 In the active mode, the system measures fissile isotopes such as 235U and 239Pu. The neutrons from a pulsed, 14-MeV neutron generator are thermalized to induce fission in the assay item. Between generator pulses, the system detects prompt-fission neutrons emitted from the fissile material. The number of detected neutrons between pulses is proportional to the mass of fissile material. This method is called the differential die-away technique.1.1.2 In the passive mode, the system detects time-coincident neutrons emitted from spontaneously fissioning isotopes. The primary isotopes measured are 238Pu, 240 Pu, and 242Pu; however, the system may be adapted for use on other spontaneously-fissioning isotopes as well, such as kilogram quantities of 238U. The number of coincident neutrons detected is proportional to the mass of spontaneously-fissioning material.1.2 The active mode is used to assay fissile material in the following ranges.1.2.1 For uranium-only bearing items, the DDT can measure the 235U content in the range from about 0.02 to over 100 g. Small mass uranium-bearing items are typically measured using the active mode and only large mass items are measured in passive mode.1.2.2 For plutonium-only bearing items, the DDT method measures the 239Pu content in the range between about 0.01 and 20 g.1.3 The passive mode is capable of assaying spontaneously-fissioning nuclei, over a nominal range from 0.05 to 15 g 240Pu equivalent.1.4 This test method requires knowledge of the relative abundances of the plutonium or uranium isotopes to determine the total plutonium or uranium mass.1.5 This test method will give biased results when the waste form does not meet the calibration specifications and the measurement assumptions presented in this test method regarding the requirements for a homogeneous matrix, uniform source distribution, and the absence of nuclear material lumps, to the extent that they effect the measurement.1.6 The complete active and passive assay of a 208 L drum is nominally 10 min or less but either mode can be extended to meet data quality objectives.1.7 Some improvements to this test method have been reported (1, 2, 3, 4).2 Discussions of these improvements are not included in this test method although improvements continue to occur.1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.9 This standard may involve hazardous materials, operations, and equipment. 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 8.1.10 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 test method is useful for determining the plutonium content of items such as impure Pu oxide, mixed Pu/U oxide, oxidized Pu metal, Pu scrap and waste, Pu process residues, and weapons components.5.2 Measurements made with this test method may be suitable for safeguards or waste characterization requirements such as:5.2.1 Nuclear materials accountability,5.2.2 Inventory verification (7),5.2.3 Confirmation of nuclear materials content (8),5.2.4 Resolution of shipper/receiver differences (9),5.2.5 Excess weapons materials inspections (10, 11),5.2.6 Safeguards termination on waste (12, 13),5.2.7 Determination of fissile equivalent content (14).5.3 A significant feature of neutron multiplicity counting is its ability to capture more information than neutron coincidence counting because of the availability of a third measured parameter, leading to reduced measurement bias for most material categories for which suitable precision can be attained. This feature also makes it possible to assay some in-plant materials that are not amenable to conventional coincidence counting, including moist or impure plutonium oxide, oxidized metal, and some categories of scrap, waste, and residues (10).5.4 Calibration for many material types does not require representative standards. Thus, the technique can be used for inventory verification without calibration standards (7), although measurement bias may be lower if representative standards were available.5.4.1 The repeatability of the measurement results due to counting statistics is related to the quantity of nuclear material, interfering neutrons, and the count time of the measurement (15) .5.4.2 For certain materials such as small Pu, items of less than 1 g, some Pu-bearing waste, or very impure Pu process residues where the (α,n) reaction rate overwhelms the triples signal, multiplicity information may not be useful because of the poor counting statistics of the triple coincidences within practical counting times (12).5.5 For pure Pu metal, pure oxide, or other well-characterized materials, the additional multiplicity information is not needed, and conventional coincidence counting will provide better repeatability because the low counting statistics of the triple coincidences are not used. Conventional coincidence information can be obtained either by changing to coincidence analyzer mode, or analyzing the multiplicity data in coincidence mode.5.6 The mathematical analysis of neutron multiplicity data is based on several assumptions that are detailed in Annex A1. The mathematical model considered is a point in space, with assumptions that neutron detection efficiency, die-away time, and multiplication are constant across the entire item (16, 17) . As the measurement deviates from these assumptions, the biases will increase.5.6.1 Bias in passive neutron multiplicity measurements is related to deviations from the “point model” such as variations in detection efficiency, matrix composition, or distribution of nuclear material in the item's interior.5.6.2 Heterogeneity in the distribution of nuclear material, neutron moderators, and neutron absorbers may introduce biases that affect the accuracy of the results. Measurements made on items with homogeneous contents will be more accurate than those made on items with inhomogeneous contents.1.1 This test method describes the nondestructive assay of plutonium in forms such as metal, oxide, scrap, residue, or waste using passive neutron multiplicity counting. This test method provides results that are usually more accurate than conventional neutron coincidence counting. The method can be applied to a large variety of plutonium items in various containers including cans, 208-L drums, or 1900-L Standard Waste Boxes. It has been used to assay items whose plutonium content ranges from 1 g to 1000s of g.1.2 There are several electronics or mathematical approaches available for multiplicity analysis, including the multiplicity shift register, the Euratom Time Correlation Analyzer, and the List Mode Module, as described briefly in Ref. (1).21.3 This test method is primarily intended to address the assay of 240Pu-effective by moments-based multiplicity analysis using shift register electronics (1, 2, 3) and high efficiency neutron counters specifically designed for multiplicity analysis.1.4 This test method requires knowledge of the relative abundances of the plutonium isotopes to determine the total plutonium mass (See Test Method C1030).1.5 This test method may also be applied to modified neutron coincidence counters (4) which were not specifically designed as multiplicity counters (that is, HLNCC, AWCC, etc), with a corresponding degradation of results.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 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 guide assists in satisfying requirements in such areas as safeguards, SNM inventory control, nuclear criticality safety, waste disposal, and decontamination and decommissioning (D&D). This guide can apply to the measurement of holdup in process equipment or discrete items whose neutron production properties may be measured or estimated. These methods may meet target accuracy for items with complex distributions of SNM in the presence of moderators, absorbers, and neutron poisons; however, the results are subject to larger measurement uncertainties than measurements of less complex items.5.2 Quantitative Measurements—These measurements result in quantification of the mass of SNM in the holdup. They include all the corrections and descriptive information, such as isotopic composition, that are available.5.2.1 High-quality results require detailed knowledge of radiation sources and detectors, radiation transport, calibration, facility operations, and error analysis. Consultation with qualified NDA personnel is recommended (Guide C1490).5.2.2 Holdup estimates for a single piece of process equipment or piping often include some compilation of multiple measurements. The holdup estimate must appropriately combine the results of each individual measurement. In addition, uncertainty estimates for each individual measurement must be made and appropriately combined.5.3 Scan—Radiation scanning, typically gamma, may be used to provide a qualitative description of the extent, location, and the relative quantity of holdup. It can be used to plan or supplement the quantitative neutron measurements. Other indicators (for example, visual) may also indicate a need for a holdup measurement.5.4 Nuclide Mapping—To appropriately interpret the neutron data, the specific neutron yield is needed. Isotopic measurements to determine the relative isotopic composition of the holdup at specific locations may be required, depending on the facility.5.5 Spot Check and Verification Measurements—Periodic re-measurement of holdup at a defined point using the same technique and assumptions can be used to detect or track relative changes in the holdup quantity at that point over time. Either a qualitative or quantitative method can be used.5.6 Indirect Measurements—Neutron measurements do not identify the radionuclide that produced the neutron signal. The specific neutron yield shall be determined independently of the neutron measurement.5.7 Modeling—Modeling is recommended as an aid in the evaluation of complex measurement situations. Measurement data are used with a radiation transport model that includes a description of the physical location of equipment and materials. Because of the complexity of neutron transport calculations, models are often developed using a transport code such as MCNP. Geometric models can also be used but, generally, do not account for phenomena such as scattering and estimation of neutron escape fraction.1.1 This guide describes passive neutron measurement methods used to nondestructively estimate the amount of neutron-emitting special nuclear material compounds remaining as holdup in nuclear facilities. Holdup occurs in all facilities in which nuclear material is processed. Material may exist, for example, in process equipment, in exhaust ventilation systems, and in building walls and floors.1.1.1 The most frequent uses of passive neutron holdup techniques are for the measurement of uranium or plutonium deposits in processing facilities.1.2 This guide includes information useful for management, planning, selection of equipment, consideration of interferences, measurement program definition, and the utilization of resources.1.3 Counting modes include both singles (totals) or gross counting and neutron coincidence techniques.1.3.1 Neutron holdup measurements of uranium are typically performed on neutrons emitted during (α, n) reactions and spontaneous fission using singles (totals) or gross counting. While the method does not preclude measurement using coincidence or multiplicity counting for uranium, measurement efficiency is generally not sufficient to permit assays in reasonable counting times.1.3.2 For measurement of plutonium in gloveboxes, installed measurement equipment may provide sufficient efficiency for performing counting using neutron coincidence techniques in reasonable counting times.1.4 The measurement of nuclear material holdup in process equipment requires a scientific knowledge of radiation sources and detectors, radiation transport, modeling methods, calibration, facility operations, and uncertainty analysis. It is subject to the constraints of the facility, management, budget, and schedule, plus health and safety requirements, as well as the laws of physics. This guide does not purport to instruct the NDA practitioner on these principles.1.5 The measurement process includes defining measurement uncertainties and is sensitive to the chemical composition, isotopic composition, distribution of the material, various backgrounds, and interferences. The work includes investigation of material distributions within a facility, which could include potentially large holdup surface areas. Nuclear material held up in pipes, ductwork, gloveboxes, and heavy equipment is usually distributed in a diffuse and irregular manner. It is difficult to define the measurement geometry, identify the form of the material, and measure it.1.6 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.1.7 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.1.8 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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4.1 This practice is suited ideally for screening samples for the presence, relative concentration, and potential class of ignitable liquid residues in fire debris.4.2 This is a very sensitive separation procedure, capable of isolating small quantities of ignitable liquid residues from a sample, that is, a 0.1 μL spike of gasoline on a cellulose wipe inside of a 1-gal can is detectable.4.3 Actual recovery will vary, depending on several factors, including adsorption temperature, container size, competition from the sample matrix, ignitable liquid class and relative ignitable liquid concentration.4.4 Because this separation takes place in a closed container, the sample remains in approximately the same condition in which it was submitted. Repeat and interlaboratory analyses, therefore, may be possible. Since the extraction is nonexhaustive, the technique permits reanalysis of samples.4.5 This practice is intended for use in conjunction with other extraction techniques described in Practices E1386, E1388, E1412, and E1413.4.6 The extract is consumed in the analysis. If a more permanent extract is desired, one of the separation practices described in Practices E1386, E1412, or E1413 should be used.1.1 This practice describes the procedure for removing small quantities of ignitable liquid residues from samples of fire debris. An adsorbent material is used to extract the residue from the static headspace above the sample. Then, analytes are thermally desorbed in the injection port of the gas chromatograph (GC).1.2 This practice is best suited for screening fire debris samples to assess relative ignitable liquid concentration and for extracting ignitable liquid from aqueous samples.1.3 This practice is suitable for extracting ignitable liquid residues when a high level of sensitivity is required due to a very low concentration of ignitable liquid residues in the sample.1.3.1 Unlike other methods of separation and concentration, this method recovers a minimal amount of the ignitable residues present in the evidence, leaving residues that are suitable for subsequent resampling.1.4 Alternate separation and concentration procedures are listed in Section 2.1.5 This standard cannot replace knowledge, skill, or ability acquired through appropriate education, training, and experience and should be used in conjunction with sound professional judgment.1.6 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 provides a quantified measure of the image artifact produced under a standard set of scanning conditions.5.2 This test method applies only to passive implants that have been established to be MR-Safe or MR-Conditional.1.1 This test method characterizes the distortion and signal loss artifacts produced in a magnetic resonance (MR) image by a passive implant (implant that functions without the supply of electrical or external power). Anything not established to be MR-Safe or MR-Conditional is excluded.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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5.1 Passive soil gas samplers are a minimally invasive, easy-to-use technique in the field for identifying VOCs and SVOCs in the vadose zone. Similar to active soil gas and other field screening techniques, the simplicity and low cost of passive samplers enables them to be applied in large numbers, facilitating detailed mapping of contamination across a site, for the purpose of identifying source areas and release locations, focusing subsequent soil and groundwater sampling locations, focusing remediation plans, identifying vapor intrusion pathways, tracking groundwater plumes, and monitoring remediation progress. Data generated from passive soil gas sampling are semi-quantitative and are dependent on numerous factors both within and outside the control of the sampling personnel. Key variables are identified and briefly discussed in the following sections.NOTE 1: Additional non-mandatory information on these factors or variables are covered in the applicable standards referenced in Section 2, and the footnotes and Bibliography presented herewith.5.2 Application—The techniques described in this practice are suitable for sampling soil gas with sorbent samplers in a wide variety of geological settings for subsequent analysis for VOCs and SVOCs. The techniques also may prove useful for species other than VOCs and SVOCs, such as elemental mercury, with specialized sorbent media and analysis.5.2.1 Source Identification and Spatial Variability Assessment—Passive soil gas sampling can be an effective method to identify contaminant source areas in the vadose zone and delineate the extent of contamination. By collecting samples in a grid with fewer data gaps, the method allows for an increase in data density and, therefore, provides a high-resolution depiction of the nature and extent of contamination across the survey area. By comparing the results, as qualitative or quantitative, from one location to another, the relative distribution and spatial variability of the contaminants in the subsurface can be determined, thereby improving the conceptual site model. Areas of the site reporting non-detects can be removed from further investigation, while subsequent sampling and remediation can be focused in areas determined from the PSG survey to be impacted.5.2.2 Monitoring—Passive soil gas samplers are used to monitor changes in site conditions (for example, new releases on-site, an increase in contaminant concentrations in groundwater from onsite or off-site sources, and effectiveness of remedial system performance) as reflected by the changes in soil gas results at fixed locations over time. An initial set of data is collected to establish a baseline and subsequent data sets are collected for comparison. The sampling and analytical procedures should remain as near to constant as possible so significant changes in soil gas results can be attributed to those changes in subsurface contaminant levels at the site that will then warrant further investigation to identify the cause.5.2.3 Vapor Intrusion Evaluation—Passive soil gas sampling can be used to identify vapor migration and intrusion pathways (see Practice E2600), with the data providing a line of evidence on the presence or absence of the compounds in soil vapor, the nature and extent in relation to potential receptors, and whether a vapor pathway is complete. Sorbent samplers can be placed beneath the slab or in close proximity to buildings to collect time-integrated samples targeting VOCs and SVOCs at concentrations often lower than can be achieved with active soil gas sampling methods.5.3 Limitations—Passive soil gas data are reported in mass of individual compounds or compound groups identified per sample location, with the reporting units generally in nanograms (ng) or micrograms (μg) per sampler and not a concentration (see 6.8). Ideally, the data produced using this method will be representative of time-weighted soil gas concentrations, present in the vicinity of the PSG sampler and sorbed on the sampler during the exposure period; however, non-uniformity of sampler design, starvation effects during sample collection, or an insufficient amount of sorbent that results in saturation of the sorbent surface area, or combinations thereof, will affect the relationship between sorbed mass and soil gas concentrations present. The degree to which these data are representative of any larger areas or different times depends on numerous site-specific factors. In general, information obtained from a passive soil gas sampling program alone is not sufficient to support a quantitative determination of soil gas concentrations.5.4 Sampler Design—Passive soil gas is an effective investigatory/monitoring tool if the appropriate quality controls are included in the technology design, which includes uniformity in the construction of the sampler. At a minimum, controls should be in place to ensure that (1) the appropriate sorbents with hydrophobic properties are used to target the compounds of concern (see Practice D6196), (2) materials used to house the sorbents are chemically-inert, non-reactive or corrosive, and will not off-gas compounds or act as competing sorbents (see Guide D5314, paragraph 6.5.3), and (3) the sorbents are housed in suitable containers that protect the sorbents, allow diffusion of the soil gas to the sorbents, and facilitate installation of the sampler to the desired sampling depth.5.4.1 Sampler Conditioning—Before being sent to the field for deployment, the PSG sampler should be conditioned to remove any potential contamination present on or in the sorbent and sampler materials or both encountered during sampler construction or storage prior to use. The conditioning process should be one that does not damage the sorptive capability of the sorbent. Following conditioning, the sampler is then capped/resealed and stored in a container that provides adequate protection against ambient sources of contamination before and after sample collection in the field, including during transport. Preparation blanks from each batch of conditioned samplers should be analyzed to verify that the sorbents were effectively conditioned and do not retain measurable masses of target compounds above reporting limits. Furthermore, when trip blanks, which are included with all shipments to and from the field, report non-detects for the targeted compounds, these QC samples provide additional evidence that the samplers were conditioned to have no measurable mass of target compounds and that the measurements on field samples originate from the site itself.5.5 Sampler Exposure Periods—Guidelines for PSG exposure periods for source identification, spatial variability assessment, and vapor intrusion evaluation should consider the project objectives, target compounds, required detection limits or anticipated soil gas concentrations or both, design of the passive sampler, matrix heterogeneity, soil types (total porosity), soil moisture level (water filled porosity), and depth to expected contaminants. Sites having coarse-grained dry soils, high concentrations, shallow groundwater or soil contamination or both, and volatile compounds typically require shorter exposure periods. Sites with finegrained, clays or moist soils or both, deep contaminant sources, low concentrations, or SVOCs, or combinations thereof, typically require longer exposure periods. Exposure periods typically range from days to weeks but can be as brief as one hour when high concentrations of target compounds are expected in the soil vapor.5.6 Sampler Spacing—Grid designs can consist of regularly spaced sampler locations, random or irregular spaced, and as transects or varying spatial intervals (see Guide D6311). Biased spacing in which smaller sample spacing is used in areas with known or suspected targets (that is, source areas) and large spacing in areas not believed to be impacted are also used. For large area investigations, a staged or phased sampling program can be used. The investigation begins with a widely spaced regular grid design. The initial soil gas results are reviewed and subsequent sampling is conducted at locations where the target compounds were observed. The subsequent survey design consists of more closely spaced samples to resolve the feature of interest in greater detail. Multiple phases of soil gas sampling can be combined to provide one comprehensive image of the soil gas results. Staged or phased investigations require multiple deployments adding costs to the overall investigations. However, areas of the site that have nondetectable values in the soil gas may be removed from further investigation.5.6.1 There is no prescribed or set sampler spacing appropriate for all sites, as sample spacing and survey design are based on project objectives and each site is unique. General recommendations for sampler spacing range from 3 to 30 m, with 7.5- to 15-m spacing when site knowledge is lacking. Infill sampling is recommended in areas having wider sample spacing initially.5.6.2 Site-specific information (investigation area size, groundwater depth, soil type and moisture content, purpose of the investigation, etc.) should be considered along with these guidelines in determining the grid spacing used. The selection of grid cell size (a direct function of the sampler spacing deployed in a grid pattern) is strongly dependent upon the relationship between both project confidence level and budget requirements. The tendency exists for investigators with constrained budgets to use overly large grid cell spacing. This action of “undersampling” normally results in inadequate, over-interpreted data with unsupported conclusions. Care shall be taken to avoid this problem (Guide D5314). In designing an effective soil gas survey to develop a rational conceptual site model, the survey objective balanced by budget should determine the sample spacing.5.7 Sampling Depth—Consideration of project objectives should be taken into account when determining deployment depth. It is ideal, when possible, to deploy samplers at the same depth to ensure data consistency. PSG samplers are generally installed from a depth of 15-cm to 1.0-m BLS; however, holes may be advanced to greater depths when appropriate, and samplers can also be suspended beneath surface flux chambers or in permanent vapor ports.5.8 Soil Types—In general, sandy soils tend to be more porous and permeable and, thus, require shorter exposure times. Conversely, soils with high clay contents tend to be less porous and permeable and typically have lower flux rates (see Practice D2487). Soil types vary in vapor permeability due to the differences in the number and interconnectivity of air-filled pores. The more air-filled, interconnected the pores are, the greater the potential flux of contaminants through the soil to the sampler. Starvation effects resulting in low bias are more likely to occur in low permeability soils where the flux through the soil matrix is limited.5.9 Effects of Soil Moisture—Because diffusion of vapors from subsurface sources to passive samplers relies on interconnected and air-filled pores within the soil column, soil moisture can have a significant effect on the flux of contaminants and, therefore, the mass of the contaminant available for adsorption by the sampling device. The use of hydrophobic sorbents minimizes the effect on sampler sensitivity, but does not change the impact of soil moisture on contaminant soil gas concentrations. As a result, areas of high soil moisture may have significantly lower soil gas results than areas of low soil moisture, even though subsurface concentrations are similar in both areas. Therefore, some knowledge of the soil moisture conditions can help in interpreting soil gas results. This knowledge is also useful for comparing results from subsequent surveys performed at a site.5.10 Effects of Target Compounds—In general, the larger the molecular weight of the compounds being targeted, the lower the vapor pressure and resulting concentrations in the soil gas, and therefore, the longer the required exposure time of the PSG samplers in the vadose zone.5.11 Sealing (Plugging) the Top of the Hole—Once the PSG sampler is inserted in the ground, the top of the hole is plugged with a material that will effectively seal the hole, such as aluminum foil or cork, which can then be covered with soil. For concrete or asphalt surfacing, an approximately 5-mm-thick mortar or quick-setting concrete patch above the plug can be used as an option to maintain the integrity of the surface while the sampler is in the ground. The materials used to plug the hole should not contribute compounds of concern and the seal should be flush mounted to keep the sampler safe from harm, prevent ingress of ambient air or surface water, and not interrupt ongoing site activities during the exposure period.5.12 Effects of Ambient Air While Installing/Retrieving Samplers—PSG samplers arrive at the site sealed to protect the sorbents from contaminants in ambient air during transport. Just prior to installation into the hole, and then again during retrieval, the sampler is exposed to ambient air for a brief period of time. The typical time of exposure to the ambient air is less than 15 s. In some instances, it may be necessary to collect a field blank using a PSG sampler to evaluate whether compounds in the ambient air potentially biased the results. To perform this quality control check, an identical PSG sampler is opened and exposed to the ambient air for approximately the same amount of time required to install and then later retrieve a PSG sampler at a designated location. The field blank is sealed at all other times and is transported to the laboratory along with the field samples. Care should be taken to minimize the sorbent exposure to ambient air during field activities. Obvious sources of contamination (for example, gas-powered electrical generators or vehicle exhaust) should not be in close proximity when installing/retrieving a sampler.NOTE 2: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/and so forth. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 Purpose—This practice covers standardized techniques for passively collecting soil gas samples from the vadose zone and is to be used in conjunction with Guide D5314.1.2 Objectives—Objectives guiding the development of this practice are: (1) to synthesize and put in writing good commercial and customary practice for conducting passive soil gas sampling, (2) to ensure that the process for collecting and analyzing passive soil gas samples is practical and reasonable, and (3) to provide standard guidance for passive soil gas sampling performed in support of source identification, spatial variability/extent determinations, site assessment, site monitoring, and vapor intrusion investigations.1.3 This practice does not address requirements of any federal, state, or local regulations or guidance or both with respect to soil gas sampling. Users are cautioned that federal, state, and local guidance may impose specific requirements that differ from those of this practice.1.4 Units—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.1.6 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTM consensus process.1.7 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 test method is used to determine the U and Pu content of scrap and waste in containers. Active measurement times have typically been 100 to 1000 s. Passive measurement times have typically been 400 s to several hours. The following limits may be further restricted depending upon specific matrix, calibration material, criticality safety, or counting equipment considerations.5.1.1 The passive measurement has been applied to benign matrices in 208 L drums with Pu content ranging from 30 mg to 1 kg.5.1.2 The active measurement has been applied to waste drums with 235U content ranging from about 100 mg to 1 kg.5.2 This test method can be used to demonstrate compliance with the radioactivity levels specified in safeguards, waste, disposal, and environmental regulations (for example, see NRC regulatory guides 5.11, 5.53, DOE Order 5820.2a, and 10CFR61 sections 61.55 and sections 61.56, 40CFR191, and DOE/WIPP-069).5.3 This test method could be used to detect diversion attempts that use shielding to encapsulate nuclear material.5.4 The bias of the measurement results is related to the item size and density, the homogeneity and composition of the matrix, and the quantity and distribution of the nuclear material. The precision of the measurement results is related to the quantity of nuclear material and the count time of the measurement.5.4.1 For both the matrix-specific and the matrix-correction approaches, the method assumes the calibration materials match the items to be measured with respect to the homogeneity and composition of the matrix, the neutron moderator and absorber content, and the quantity of nuclear material, to the extent they affect the measurement.5.4.2 It is recommended that measurements be made on small containers of scrap and waste before they are combined in large containers. Special arrangement may be required to assay small containers to best effect in a large cavity general purpose shuffer.5.4.3 It is recommended that measurements be made on containers with homogeneous contents. In general, heterogeneity in the distribution of nuclear material, neutron moderators, and neutron absorbers has the potential to cause biased results.5.5 This test method requires that the relative isotopic compositions of the contributing elements are known.5.6 This test method assumes that the distribution of the contributing isotopes is uniform throughout the container when the matrix affects neutron transport.5.7 This test method assumes that lump affects are unimportant—that is to say that large quantities of special nuclear material are not concentrated in a small portion of the container.5.8 For best results from the application of this test method, appropriate packaging of the items is required. Suitable training of the personnel who package the scrap and waste prior to measurement should be provided (for example, see ANSI 15.20, Guide C1009, Guide C1490, and Guide C1068 for training guidance). Sometimes site specific conditions and requirements may have greater bearing.1.1 This test method covers the nondestructive assay of scrap and waste items for U, Pu, or both, using a 252 Cf shuffler. Shuffler measurements have been applied to a variety of matrix materials in containers of up to several 100 L. Corrections are made for the effects of matrix material. Applications of this test method include measurements for safeguards, accountability, TRU, and U waste segregation, disposal, and process control purposes (1, 2, 3).21.1.1 This test method uses passive neutron coincidence counting (4) to measure the 240Pu-effective mass. It has been used to assay items with total Pu contents between 0.03 g and 1000 g. It could be used to measure other spontaneously fissioning isotopes such as Cm and Cf. It specifically describes the approach used with shift register electronics; however, it can be adapted to other electronics.1.1.2 This test method uses neutron irradiation with a moveable Cf source and counting of the delayed neutrons from the induced fissions to measure the 235U equivalent fissile mass. It has been used to assay items with 235U contents between 0.1 g and 1000 g. It could be used to assay other fissile and fissionable isotopes.1.2 This test method requires knowledge of the relative isotopic composition (See Test Method C1030) of the special nuclear material to determine the mass of the different elements from the measurable quantities.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 The techniques described in this test method have been applied to materials other than scrap and waste. These other applications are not addressed in this test method.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. Specific precautionary statements are given in Section 8.

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