Ciddi Nükleer Kazalardaki Belirsizliklerin Radyolojik ve Nükleer Dağılım Tahminlerine Etkisi

Year 2024, Volume: 52 Issue: 5, 224 - 234, 12.12.2024

Ahmet Kağan Mercan

https://doi.org/10.15671/hjbc.1571208

Abstract

Halkın ve çevrenin korunması, düzenleyicilerin temel görevidir ve tesisin bütünlüğünü sürdürmek için önlemler geliştirilmiştir. Buna ek olarak, olası ciddi kazaların sonuçlarına karşı etkileri hafifletmek için stratejiler geliştirmek gerekir. Ciddi kaza yazılımları kullanılarak değerlendirme, düzenleyiciler tarafından kabul edilen yaygın bir uygulamadır, ancak bu araçlar sınırlı deneysel veriler kullanılarak oluşturulan modellere dayanır. Dolayısıyla, kaza için güvenilir bir değerlendirme, sonuçların belirsizliklerinin nicelendirilmesini de gerektirir.

Bu çalışmada, VVER-1000 üzerinde seçilmiş bir kaza durumu ASTEC aracılığıyla gerçekleştirilmiş ve ASTEC kodunun belirsizlikleri, potansiyel etki aralığının belirlenmesi amacıyla KATUSA aracılığıyla nicelendirilmiştir. Seçilen belirsiz parametrelere göre 100 örnek oluşturulmuş, bunların olasılık dağılım fonksiyonları (PDF'ler) ve değişim aralıkları belirlenmiş ve sonuçları değerlendirmek için birden fazla ASTEC kod simülasyonu gerçekleştirilmiştir. Son olarak, Zaporizhzhia NGS'de en kötü senaryo ve en iyi tahmin senaryolarıyla JRODOS hesaplaması yapılarak, seçilen bölgedeki radyolojik etki farkı belirlenmiştir. Sonuçlar, seçilen dönemde seçilen alanın neredeyse iki kat daha yüksek radyolojik kirliliğine maruz kaldığını ve nüfusa neredeyse 1.5 kat daha yüksek dozun ulaştığını göstermektedir.

Keywords

KBRN, JRODOS, KATUSA, Belirsizliklerin Analizi, Ciddi Kazalar, Radyolojik Etki, VVER-1000

Impact of Uncertainties of Nuclear Severe Accidents on Radiological and Nuclear Dispersion Predictions

Abstract

Protection of the public as well as the environment is primal task of the regulators and provisions to sustain integrity of the plant have been developed. In addition to that, the consequences of possible severe accidents are necessary to develop strategies to mitigate the impact. Evaluation by using severe accident tools is common practice accepted by regulators, but these tools rely on models that generated by using limited experimental data. Thus, reliable evaluation of the accident also requires uncertainty quantification of the results.

In this work, selected accident case on VVER-1000 is performed by using ASTEC tool and the uncertainties of the ASTEC code is quantified by using KATUSA tool with the goal of determination of the potential impact range. 100 samples are generated according to selected uncertain parameters, their probabilistic distribution functions (PDFs) and variation range, and multiple ASTEC code simulations are performed to evaluate the results. Finally, JRODOS calculation is performed on Zaporizhzhia NPP with worst-case and best-estimate scenarios to identify the difference on the radiological impact. The potential difference on the inventories results with almost two times higher radiological contamination of the selected area on selected period which causes almost 1.5 times higher doses on the population.

Keywords

CBRN, KATUSA, JRODOS, Uncertainty Quantification, Severe Accidents, Radiological Impact, VVER-1000

References

• NEA-OECD, “The Fukushima Daiichi Nuclear Power Plant Accident: Nuclear Safety,” NEA Report No:7161, (2013)Paris.
• D. Manara, D. Jacquemin, J. P. Van Dorsselaere, P. D. Bottomley, M. Adorni, C. Journeau, Y. Pontillon, T. Lind, L. E. Herranz, F. Rocchi, S. P., J. C. de la Rosa Blul, S. Bechta, J. Duspiva, I. Kljenak and P. Dejardin, “Severe Accident Research Priority Ranking: A New Assessment Eight Years After The Dukushima Daiichi Accident,” in 9TH Conference on Severe Accident Research (ERMSAR 2019),, Prague, 2018.
• P. Chatelard, S. Belon, L. Bosland, O. Coindreau, F. Cousin, C. Marchetto, H. Nowack and L. Piar, “Focus on the main modelling features of ASTEC V2.1 major version,” in 7th European Review Meeting on Severe Accident Research (ERMSAR2019), Marseille, 2015.
• H. Austregesilo, P. Schöffel, D. Cron, F. Weyermann, A. Wielenberg and K. W. Wong, “ATHLET-CD 3.3 User's Manual,” Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH, GRS-P-4/Vol. 2(2021), Rev. 0
• L. Humphries, V. Figueroa, M. Young, D. Louie and J. Reynolds, “MELCOR Computer Code Manuals (No. SAND-2015-6692R),” Sandia National Lab. (SNL-NM), Albuquerque, NM (United States), 2015
• W. Raskob, D. Trybushnyi, I. Ievdin and M. Zheleznyak, “JRODOS: Platform for improved long term countermeasures modelling and management,” Radioprotection, vol. 46(2012), no. 6, pp. 731-736.
• T. Bander, “an atmospheric dispersion program for evaluating design basis accidental releases of radioactive materials from nuclear power stations,” Y 3.N 88:25/2858, (1982)Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington.
• P. Chatelard and L. Laborde., “Synthesis of the ASTEC V2.2 code validation vs. experimental,” in he 10th European Review Meeting on Severe Accident Research (ERMSAR-2022), Karlsruhe, 2022
• A. Stakhanova, F. Gabrielli, V. P. E. Sanchez-Espinoza and A. Hoefer, “Uncertainty and Sensitivity Analysis of the ASTEC simulations results of a MBLOCA scenario at a Generic KONVOI Plant using FSTC tool,” in The 10th European Review Meeting on Severe Accident Research (ERMSAR2022), (pp. 861-872). Karlsruhe: KITopen-ID: 1000151444, DOI: 10.5445/IR/1000151444, 2022.
• L. Herranz, “ASTEC code development, validation and applications for severe accident management within the CESAM European project,” in ICAPP, Nice, 2015
• A. K. Mercan, F. Gabrielli, V. H. Sanchez-Espinoza and W. Raskob, “Analysis of the consequences of a LBLOCA with SBO severe accident in a generic VVER-1000 by means of ASTEC and JRODOS codes,” Nuclear Engineering and Design, Volume 400,(2022), p. 112078.
• K. Ivanov, B. Ivanov, P. Groudec, M. Pavlova and V. Hadijev, “VVER-1000 Coolant Transient Benchmark-Phase 1 (V1000CT-1) Volume 1: Main Coolant Pump (MCP) switching on- Final Specifications,” , OECD Publishing, Paris, 2002
• F. Gabrielli, A. Stakhanova, V. Sanchez-Espinoza, E. Pauli, A. Hoefer and H. Feldmann, “Impact of Realistic Fuel Inventories on the Radiological Consequences of a Severe Accident Scenario in a Generic KONVOI Plant by means of the ASTEC code,” in KERNTECHNIK, Leipzig, 2022.
• R. L. Iman, J. C. Helton and J. E. Campbell, “An approach to sensitivity analysis of computer models, Part 1. Introduction, input variable selection and preliminary variable assessment,” Journal of Quality Technology, vol. 13,(1981) no. 3, pp. 174-183.
• W. K. Hastings, “Monte Carlo Sampling Methods Using Markov Chains and Their Applications,” Biometrika, vol. 57(1970), pp. 97-109.
• A. K. Mercan, “Severe accident investigations for VVER-reactors including radiological impact and quantification of uncertainties,” KIT, Karlsruhe, 2024.
• International Atomic Energy Agency (IAEA), “INES Rating Information and User’s Manual,” Non-serial Publications, IAEA, Vienna, 1990.