Comparison between NaI(Tl) and CsI(Tl) detectors in detection of flooded flexible risers using MCNP6
DOI:
https://doi.org/10.15392/2319-0612.2026.3062Palabras clave:
MCNP, Gamma transmission, Flexible risers, NaI(Tl) detectorsResumen
Flexible risers are multilayer pipes used in offshore oil production, combining flexibility and mechanical strength through several layers of different materials. Although designed to withstand severe operating conditions, loss of watertightness may occur, allowing seawater ingress that can lead to corrosion of metallic components, degradation of thermal insulation, and mechanical failure, ultimately compromising riser integrity and operational safety. Regular inspection is therefore essential to ensure facility’s operation without riser’s repair interruption. Gamma transmission is a promising technique for this purpose. This study proposes a methodology to detect seawater ingress using two NaI(Tl) scintillation detectors and compares its performance with an array of twenty-three CsI(Tl) scintillation detectors. The results showed excellent agreement between I/I₀ and seawater ingress percentage for both detector configurations. However, NaI(Tl) detectors presented approximately 25 times higher detection efficiency, leading to improved counting statistics, shorter acquisition time, or reduced source activity, depending on operational requirements. In addition, NaI(Tl) detectors enable gamma-ray spectrometry using simpler electronic instrumentation. The results were obtained by simulations with the MCNP computer code.
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Referencias
[1] AMERICAN PETROLEUM INSTITUTE. API Specification 17J: Specification for Unbonded Flexible Pipe. Washington, DC: API, 2021.
[2] DNV. DNV ST F119: Thermoplastic composite pipes. Høvik, Norway: DNV, 2019.
[3] AMERICAN PETROLEUM INSTITUTE. API RP 17B: Recommended Practice for Flexible Pipe. Washington, DC: API, 2020.
[4] MARINHO, C. A. et al. Annulus flooding detection system in flexible pipes using gamma-rays transmission technique. Applied Radiation and Isotopes, Amsterdam, v. 184, 110177, 2022. DOI: https://doi.org/10.1016/j.apradiso.2022.110177
[5] FERREIRA, C. A. M. Detecção de alagamento de anular em dutos flexíveis usando a técnica de transmissão de radiação gama. 2021. Tese (Doutorado em Engenharia Nuclear) – Universidade Federal do Rio de Janeiro, Rio de Janeiro, 2021.
[6] PNNL. Compendium of Material Composition Data for Radiation Transport Modeling. Washington: Pacific Northwest National Laboratory, 2021. (PNNL-15870, Rev. 2).
[7] SALGADO, C. M. et al. Validation of a NaI(Tl) detector’s model developed with MCNP-X code. Progress in Nuclear Energy, Amsterdam, v. 59, p. 19-25, 2012. DOI: https://doi.org/10.1016/j.pnucene.2012.03.006
[8] SALGADO, C. M. et al. Conceitos básicos. In: SALGADO, C. M. et al. Aplicação de técnica nuclear e rede neural artificial na indústria petrolífera: estudos de casos. Ponta Grossa: Atena Editora, 2025. p. 35-41.
[9] CONTI, C. C.; SALINAS, I. C. P.; ZYLBERBERG, H. A detailed procedure to simulate an HPGe detector with MCNP5. Progress in Nuclear Energy, Amsterdam, v. 66, p. 35-40, 2013. DOI: https://doi.org/10.1016/j.pnucene.2013.03.003
[10] GOORLEY, T. et al. Features of MCNP6. Annals of Nuclear Energy, Amsterdam, v. 87, p. 772-783, 2016. DOI: https://doi.org/10.1016/j.anucene.2015.02.020
[11] CONTI, C. C.; ANJOS, M. J.; SALGADO, C. M. Improved Rayleigh to Compton scattering ratio curves for mass attenuation coefficients determination for X‐ray fluorescence analysis. X‐Ray Spectrometry, New Jersey, v. 46, p. 522-528, 2017. DOI: https://doi.org/10.1002/xrs.2790
[12] X‐5 MONTE CARLO TEAM. MCNP — A General Monte Carlo N-Particle Transport Code, Version 5, Volume I: Overview and theory. Los Alamos: Los Alamos National Laboratory, 2003a. (LA‐UR‐03‐1987).
[13] X‐5 MONTE CARLO TEAM. MCNP — A General Monte Carlo N-Particle Transport Code, Version 5, Volume II: User´s guide. Los Alamos: Los Alamos National Laboratory, 2003b. (LA‐CP‐ 03‐0245).
[14] PELOWITZ, D. B. MCNP6 User's manual-version 1.0. Los Alamos: Los Alamos National Laboratory, 2013. (LA‐CP‐13‐00634).
[15] SALGADO, C. M. et al. Conceitos básicos. In: SALGADO, C. M. et al. Aplicação de técnica nuclear e rede neural artificial na indústria petrolífera: estudos de casos. Ponta Grossa: Atena Editora, 2025a. p. 34-35. DOI: https://doi.org/10.22533/at.ed.4292518062
[16] SALINAS, I. C. P.; CONTI, C. C.; LOPES, R. T. Effective density and mass attenuation coefficient for building material in Brazil. Applied Radiation and Isotopes, Amsterdam, v. 64, p. 13-18, 2006. DOI: https://doi.org/10.1016/j.apradiso.2005.07.003
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Derechos de autor 2026 Claudio de Carvalho Conti, César Marques Salgado, William Luna Salgado, Roos Sophia de Freitas Dam, Ricardo Tadeu Lopes
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