Nuclear waste monitoring

Similar demands for reference materials also arise in connection with the monitoring of radioactivity in and around nuclear installations (nuclear power plants, nuclear fuel and reprocessing plants, and nuclear waste facilities). These, in fact, are now the main applications of radionuclide reference materials. 

Process monitoring poses two additional challenges compared to these automated fluidic separation methods. First, methodology for automated sample preparation must be developed, and second, the entire sample preparation-separation-detection system must be developed to operate on-line or at-site under unattended computer control, including sample transport through all the steps. Sample preparation is particularly critical for nuclear-waste and nuclear-process streams due to the complexity of the sample matrix and the uncontrolled valence states of several of the potential analytes. 

FIGURE 9.19 Simplified schematic diagram illustrating sample preparation, separation, and detection for an on-line analyzer for the continuous monitoring of the total "Tc content of nuclear-waste process streams. A number of zero-dead volume syringe pumps and valves are not shown. 

Corrosion may be monitored by measuring changes in thickness with time using ultrasonic thickness gages. An automated ultrasonic inspection system has been devised and used in monitoring corrosion in nuclear waste containers and typical variations in ultrasonic indications in corroded and uncorroded areas have been recorded successfully. Major types of equipment inspection by ultrasonic technique has been done in mill components, power equipment, jet engine parts, aircraft components, railway materials, automotive components and other machinery components. 

An interesting example of an extractant is n-octylphenyl-iV,iV-diisobutylcarbomyl-methylphosphine oxide (Scheme 5) [48]. This nuclear extractant can concentrate nuclear waste by up to 10 and Dr. P. Horwitz from Argonne National Laboratories won a IR-100 award for the development of the TRUEX process [147]. Monitoring the reaction by P-NMR indicates that nucleophilic substitution occurs first, followed by proton abstraction to form the anion [148]. 

Usually one distinguishes between "near field" and "far field" effects of radioactivity releases. Near field effects are observed close to the release source, as for example the nuclear power plant or nuclear waste storage facility. The dissolution of nuclear waste by rain or ground water is a typical near field problem. As the source is known, it can be controlled and its environment monitored. If the radioactivity exceeds permitted levels, access to the contaminated area can be restricted. Far field effects involve the behavior of radionuclides which have spread out of such a restricted area, caused either by nuclear power accidents and weapons tests or by leakage from nuclear power plants. 

Egorov, O. B., O Hara, M. J., Addleman, S. R., Grate, J. W. 2003. Automation of radiochemical analysis from groundwater monitoring to nuclear waste analysis in Radioanalytical Methods in Interdisciplinary Research Fundamental to Cutting Edge Applications. ASC Symposium Series 868. Washington, DC ACS. 

In the same way, RS can be used in basins or rivers to detect or measure the concentration of several pollutants like nitrate or nitrite, due to intensive agriculture. This is applied for example to monitor the nitrate and nitrite in the nuclear waste tank. The principle of these sensors can be applied for several other salts or pollutants after a preliminary study to establish a reliable calibration. 

Young RP, Martin CD (1993) Potential Role of Acoustic Emission/Micro-seismicity Investigations in the Site Characterization and Performance Monitoring of Nuclear Waste Repositories. Int J Rock Mech Min Sci Geomech 30 797-803... 

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