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6 Radioactive Sources and Alternative Technologies in Industrial Applications
Pages 115-140

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From page 115...
... There are more than 1,000 licensees of radiography cameras in the United States.3 Industrial radiography relies on transmission and absorption/attenuation of short-wavelength electromagnetic energy (gamma-ray photons and x-rays) to visualize structures such as welds and castings for internal defects or porosity; gas and oil pipes to detect blockage, corrosion, and pipe wall thickness; industrial structures to ensure that there are no cracks or blockages; and aircraft and automobile parts for defects.
From page 116...
... system. Table 1.2 shows the half-life and radioactive emissions and energies of these radioisotopes, and Table 6.1 summarizes the basic characteristics of industrial radiography cameras based on the particular radioisotope.
From page 117...
... directional radiography camera off and (c)
From page 118...
... Gamma radiography cameras can operate under challenging climatic and physical conditions. Most industrial radiography cameras are designed to withstand normal and accident conditions in use in accordance with the applicable standard (ISO 3999)
From page 119...
... Most x-ray systems are more suitable for permanent installation work and cannot be used at most temporary job sites economically because of their size, weight, and accessibility and electrical power requirements, and they usually require expensive scaffolding. In comparison, the source guide tubes used in gamma radiography cameras can be introduced into extremely small, confined areas to produce radiographic images.
From page 120...
... However, the need for frequent costly replacement of the tubes and for frequent use still make gamma radiography the more reliable and preferred option. As noted in Chapter 4, RadiaBeam, a small business recipient of the National Nuclear Security Administration's Small Business Innovation Research (SBIR)
From page 121...
... Although only about 160 hours of training are required to receive certification to operate this device, the mandatory requirements include the principles of radiation and radiography, safety training, radiographic film interpretation and processing, as well as on-the-job training as a radiographer's assistant.5 With its ease and low cost of operation and ability to be used in remote locations without external power, many developing countries will continue to use the gamma equipment in lieu of x-ray systems. The committee is aware of significant work being done in France to identify replacement technologies for gamma radiography cameras.
From page 122...
... Most NDT engineers weigh inspection methods for detectability of defects, type of defect in the subject material, accessibility, and economics of the method being utilized. 6.2 INDUSTRIAL GAUGES Fixed radioactive industrial gauges have been used throughout industry for 70 years for measuring the thickness, density, or fill level of a product while it is being manufactured or processed without contacting the material itself.
From page 123...
... The gauge sources are permanently mounted externally from the vessel and require high energy to penetrate the walls. 6.2.2 Alternative Technologies As mentioned above, radiometric measurement systems, that is, those using radioactive sources, are typically used when there are extreme process conditions, such as high temperatures, high pressures, and corrosive industrial environments, because radiometric measurements do not require contact with the material being measured.
From page 124...
... This technique can cover a large range of different applications and can detect differences of a few millibars. 6.2.3 Alternative Technology Adoption Considerations The major consideration for adopting alternative technologies to replace gauges using radioactive sources is the capability to operate in harsh process environments where the measurement system is not in direct contact with the material being measured, as mentioned previously.
From page 125...
... For some applications there is no viable alternative technology that can currently replace the use of gauges with radioactive sources. As with industrial radiography, the use of alternative technologies is now complementary to the use of gauges with radioactive sources, and this condition will probably continue into the near future.
From page 126...
... , measures the voltage difference between electrodes in a downhole tool. By adding a source of electrical current in the sonde, resistivity can be measured between the TABLE 6.3 Well Logging Techniques Technique Method Signal Source Geologic Parameter Sought Nonnuclear Resistivity LWD, wireline Artificial electric current Formation water saturation Spontaneous potential Wireline Natural electrical potential Formation composition, water content Induction LWD, wireline Electromagnetic coils Formation composition, water content RF dielectric Wireline RF antenna Formation composition, water content Pressure Wireline Pressure in formation Fluid content Sonic Wireline Acoustic transceiver Fluid content, porosity Nuclear magnetic resonance Wireline Media in magnetic field Fluid content, porosity Conventional Radioisotope Sources Gamma-gamma density LWD, wireline Cesium-137 Formation density, shale content Elemental composition LWD, wireline AmBe Formation composition Neutron moderation LWD, wireline AmBe Hydrogen content Alternative Neutron Sources Neutron cross-section LWD, wireline D-T accelerator Formation density, porosity Elemental composition LWD, wireline D-T accelerator Formation composition Neutron moderation LWD, wireline D-T accelerator Hydrogen content NOTE: AmBe = americium-241/beryllium; D-T = deuterium-tritium; LWD = logging while drilling; RF = radio frequency.
From page 127...
... Porosity and permeability of geological formations depend on the fluid content and the pore spaces containing fluids. By applying a strong magnetic field, the hydrogen atoms in the fluid (typically water and hydrocarbons)
From page 128...
... Diatoms Sand with thin silt and clay layers 100 100 Coarse sand, with additional fine sand in lower part Interbedded clay, silt, and fine sand 40 40 Washout Begin flow Medium to fine sand 150 150 Fine sand to silt with clay layers. Ostracods in lower part.
From page 129...
... Both technologies are characterized by stable radiation emissions that, unlike many candidate alternative technologies, are not affected by extreme downhole environmental conditions such as continuous and intense mechanical shock and vibration, high temperatures, and high pressures. Both source types contain radioisotopes held in solid refractory oxides or glass ceramics that are securely sealed using double- or triple-walled metal containments.
From page 130...
... . Some benefits and limitations of alternative technologies using deuterium and/or tritium versus AmBe for neutron sources are summarized in Table 6.5.
From page 131...
... 6.3.3 Alternative Technology Adoption Considerations As described in a previous section, alternative replacement of Category 3 cesium-137 radioactive sources such as those used in well logging has not been a priority because of the lower activity, and no progress with adopting alternatives has been made. This section focuses on alternative technology adoption considerations associated with AmBe neutron sources Driven by safety and security concerns, the petroleum industry has been investigating the use of alternative neutron sources for well logging for a number of years (Bond et al., 2011)
From page 132...
... Large capital purchases or changes in technology would not be feasible for many companies in the current market environment.10 As a consequence of reduced utilization, many cesium-137 and AmBe neutron sources 10  Kenny Jordan, Association of Energy Service Companies, presentation to the committee on October 13, 2020.
From page 133...
... As noted above, only a few of the major service providers have the R&D capability to develop alternatives to radioactive sources. Without a significant future market, these companies would not have a financial incentive to make such investments.
From page 134...
... The cesium-137 source used is in the form of cesium chloride. Because of its ease of dispersibility, cesium chloride raises security concerns.
From page 135...
... 6.4.2 Alternative Technologies There are no obvious replacements for cesium-137 irradiators as a reference radiation field for ionizing radiation metrology. The uniqueness of using cesium-137 for metrology is the precision that its characteristics offer (see Table 6.6)
From page 136...
... The committee found that NIST is not taking steps to prepare for a possible policy change by exploring alternative technologies and performing equivalency tests to ensure that there are no adverse impacts to current calibration and testing capabilities. If a substitute for cesium-137 calibrators became available in the future that could meet all of the metrological requirements, then all documentary standards published to date, and regulations from the various regulatory bodies (such as the U.S.
From page 137...
... to assist Russia in removing and securing 180 RTGs in the coastal areas of northwest Russia along the Barents, White, and Kara seas. Norway also had provided solar installations as alternative power sources to replace the RTGs that powered lighthouses (Digges, 2015)
From page 138...
... The primary technological challenges remaining in the development of the technology are demonstrating cost-effective, repeatable, and high-quality fuel capsule fabrication and conducting the rigorous testing required to qualify any RTG for spaceflight. The developers also recognized the market risk, given the level of uncertainty of the nuclear and space industries.17 6.5.2 Alternative Technologies As noted above, ground-based use of RTGs has been eliminated.
From page 139...
... Recommendation H: The National Nuclear Security Administration should engage with other offices within the Department of Energy, the National Science Foundation, and professional societies, to support equivalency studies for well logging and industrial radiography service providers that are considering replacing their radioactive sources and adopting an alternative technology. The findings of these studies should be made broadly available.
From page 140...
... There is an opportunity that could potentially be addressed by collective actions of industry associations with the partnership and support of government agencies. As to further development and adoption of alternative technologies for gamma radiography, experts who presented at IAEA conferences in 2013 and 2019 have recognized that replacement with ultrasonic testing is at least several years away.


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