**5. Case studies for continual improvement**

278 Environmental Monitoring

Periodic maintenance and inspection requirements may often be prescribed by regulations. However, the QA program should address the frequency by which maintenance and inspections are conducted. These requirements can easily be adapted into a preventive

In addition to periodic maintenance and inspection, measurement and test equipment are to be calibrated periodically. The specific calibration methods utilize prescribed methods and traceable reference standards. Generally, calibrated equipment is labeled with the

System performance criteria assures overall satisfactory program operation. Performance criteria can cover the operational requirements, transmission factors, and flow ranges, which are used to identify normal system operations. Tracking and trending of data can supplement and monitor the criteria by enabling the user to see outlier data and observe trends in data over time. The tracking and trending of data can also indicate potential

Self-assessment programs are intended to provide a mechanism for continual improvement in programmatic elements (e.g., procedures, management systems) and operational elements (e.g., monitoring systems, permit compliance) of a program. Periodic review of program elements begins with the planning of an assessment. Once the assessment scope and intent are established, criteria can be evaluated, and strengths and weaknesses identified. Corrective actions can then be assigned and implemented to improve areas of weakness or non-compliance. Once actions are complete, an effectiveness review should be

Fig. 8. Basic components of a QA program

changes to program emissions or in equipment operations.

conducted to verify adequate corrective action implementation.

maintenance program.

calibration and expiration dates.

In addition to the periodic use of internal and external assessments, the researcher should prepare to embrace opportunities to improve the sampling and monitoring base of knowledge. The assessment process provides for the necessary feedback to make incremental changes in a program to improve the overall result. The reporting of new or unique operations, special studies, or a resolution to a monitoring question provides information valuable to other programs.

Below are two examples of current, evaluative research areas: air sample volume measurements, and the deposition of material on a sample filter paper. However, there are many areas for improvement, and individuals can make their own contributions.

#### **5.1 Air sample volume measurement evaluation**

Determination of the sample volume is critical in collecting ambient air samples for environmental monitoring. Errors in the sample volume measurement are directly proportional to errors in the calculated sample concentration (Fritz, 2009). A variety of instruments are available to measure flow and can include rotameters, electronic mass flow controllers, and venturi meters (Wight, 1994). Fritz (2009) reported on the implementation of a dry-gas meter application to air sample volume measurements in lieu of a more cumbersome and less accurate two-point manual airflow measurement and sample duration. The new method showed improved reliability and measurement resolution, reduced error, and more accurate concentration calculations. The evaluation was conducted over two phases that included a system set-up identical to the field configuration and a testing phase where the new dry-gas meters were installed in the actual sampling network.

With reported results, users can apply the basics of their work into their own evaluations applicable to their particular situation. Consider for example that the air sample volume measurement evaluation is being evaluated for an area without adequate electricity or based on filter flow characteristics. In the first case where electricity is necessary to run a sample pump, solar arrays may be an alternative. One could reasonably create a limited project for the facility to determine the appropriateness of such a system and recommend whether to utilize it in a broader program. For this second case, evaluating sample filters for pressure drop (Barnett & Kane, 1993) may be studied to determine if alternative filter sizes are adequate to meet the air sample volume requirements; however, other considerations may impact the final decision such as the ability to reliably analyze the filter, the overall spectral properties of the radioisotope(s), and the ability to ash the filter easily for additional laboratory analyses.

#### **5.2 Sample filter deposition evaluation**

Researchers have probed into the major factors affecting the measurements of radioactivity on air samples collected on filters (Stevens & Toureau, 1963; Higby, 1984). These factors

Concepts for Environmental Radioactive Air Sampling and Monitoring 281

This work was conducted at the Pacific Northwest National Laboratory, which is operated

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**7. Acknowledgment** 

**8. References** 

include particles sizes, filter types, filter loading and burial depths, and analysis of energy spectrums. More recently, others have evaluated sample filter deposition characteristics by conducting studies and using computer simulations (Luetzelschwab et al., 2000; Huang et al., 2002; Geryes et al., 2009; Barnett et al., 2009). From recent publications, additional information is now available on the self-absorption that occurs in filters, the measurement losses associated with the filter loading, and the use of Monte Carlo simulations (Fig. 9) to assess the energy spectra in different geometries. Ongoing research in this area is still warranted, given that standards call out a correction factor for self-absorption effects of more than 5% (ISO, 2010; ANSI, 2011).

Fig. 9. Comparison of an experimental and simulated energy spectrum in a filter (Geryes et al., 2009)

#### **6. Conclusion**

Concepts for environmental radioactive air sampling and monitoring include establishing the basis for sampling/monitoring, criteria for sampling media and analytical requirements, and reporting and compliance. The processes utilized include a standards based and a DQO approach that should be integrated and applied to both direct effluent and environmental surveillance sampling and monitoring. In addition, program improvement can be enhanced through the sharing of knowledge derived from routine operations and the implementation of tested and reviewed ideas. The overall program is used to demonstrated to the stakeholders that the emissions of radioactive materials to the environment is below regulatory limits and that those doses reported from such emissions are reasonably and conservatively accurate.
