Measurement and Modeling of Shielding and Attenuation Effects on Radiation Portal Monitors

Center for Nuclear Security Science and Policy Initiatives

Texas A&M Engineering Experiment Station

Measurement and Modeling of Shielding and Attenuation Effects on Radiation Portal Monitors

 

Abstract:

The Second Line of Defense program has deployed a worldwide network of Radiation Portal Monitors to help stop the illicit trafficking of radioactive material. The detection of this type of material can be affected by the spatial and temporal changes in natural background radiation (NBR). Work on this project has focused on NBR effects caused by building materials used in the construction of the roadbed and surrounding structures. Concrete core samples were taken from the ORNL portal test area and delivered to TAMU. The NBR of the samples was measured using an HPGe detector. Neutron Activation Analysis was conducted on the samples to determine their elemental composition. In addition, radiographs of the samples were taken to determine their internal structure. From this information a student using MCNP, was able to construct a radiation transport simulation using an accurate representation of NBR isotopes in the concrete. Eventually the techniques and simulations developed from this study will help predict RPM response before construction begins. Following the radiography of the core samples to determine the internal structure, accurate ISOCS modules will by generated. This will allow more accurate spectral analysis of the concrete to determine the NBR content. These results will be used to refine the existing MCNP model. The model will be benchmarked against field measurements from the ORNL test bed. The simulations resulting from this work will be useful tools for the Second Line of Defense program to determine NBR around radiation portal monitors.

Powdered Concrete Samples Used for Experiments

Powdered Concrete Samples Used for Experiments

 

Associated Publications:

  1. M.B. Fitzmaurice, C.M. Marianno, A.A. Solodov , "Developing a Methodology for Determination of Elemental Composition of Shielding Materials", Journal of Health Physics, 109, 4 (2015).

  2. C.M. Ryan , C.M. Marianno, W.S. Charlton, A.A. Solodov, J. Livesay, and B. Goddard, "Predicting Concrete Roadway Contribution to Gamma-ray Background in Radiation Portal Monitor Systems", Nuclear Technology, 186, 3 (2014).

  3. M. Fitzmaurice, "Developing a Methodology for Characterizing the Effects of Building Materials' Natural Radiation Background on a Radiation Portal Monitoring System", M.S. Thesis, Nuclear Engineering, Texas A&M University, College Station, TX (2012).

  4. M.B. Fitzmaurice, A.A. Solodov, C.M. Marianno, W.S. Charlton, J. Livesay, and T. Guzzardo., "Developing a Methodology for Characterization of Building Materials' Natural Radiation Background and Integration into an MCNP Model for Radiation Portal Monitoring Systems", 53rd Annual Meeting of the Institute of Nuclear Materials Management, Orlando, Florida, 15-19 July 2012.

  5. J.M. Osborn, C.M. Marianno, A.A. Solodov, W.S. Charlton, "Concrete Characterization Using Gamma-ray Interaction Methods", 53rd Annual Meeting of the Institute of Nuclear Material Management, Orlando, FL, July 15-19, 2012.

  6. S. Revis, "Determination and Mitigation of Precipitation Effects on Portal Monitor Gamma Background Levels", M.S. Thesis, Nuclear Engineering, Texas A&M University, College Station, TX (2012).

  7. C.M. Ryan, C.M. Marianno, W.S. Charlton, W.D. James, "Neutron activation analysis of concrete for cross-border nuclear security", Journal of Radioanalytical and Nuclear Chemistry, 291 (2012).

  8. C.M. Marianno and C.M. Ryan, "Examining a Potential Technique to Determine Gamma-Ray Background for Radiation Portal", Canberra Users Group Meeting, Dallas, TX, July 11-15, 2011.

  9. C.M. Ryan, "Determining the Impact of Concrete Roadways on Gamma Ray Background Readings for Radiation Portal Monitoring Systems", M.S. Thesis, Nuclear Engineering, Texas A&M University, College Station, TX (2011).

  10. C.M. Ryan, C.M. Marianno, W.S. Charlton, A.A. Solodov, R.J. Livesay, "Determining the Effect of Concrete Roadways on Gamma-ray Background for Radiation Portal Monitoring Systems", 33rd ESARDA Annual Meeting: Symposium on Safeguards and Nuclear Material Management, May 16-20, 2011, Budapest, Hungary.

  11. C.M. Ryan, C.M. Marianno, W.S. Charlton, and W.D. James, "Neutron Activation Analysis of Concrete for Cross-Border Nuclear Security", 13th International Conference on Modern Trends in Activation Analysis, College Station, TX, March 13-18, 2011.

  12. C.M. Ryan, C.M. Marianno, W.S. Charlton, A.A. Solodov, and J. Livesay, "Determining the Effects of Construction Materials on Background Readings for Second Line of Defense Program Portal Monitoring Systems", 51st Annual Meeting of the Institute of Nuclear Materials and Management, Baltimore, MD, USA, July 11-15, 2010.