Comparative Trend Analysis of Deep Disposal Research by SKB and POSIVA Using LDA Topic Modeling

Minhwan Choi; Byung-Gon Chae; Junghae Choi

doi:10.9720/kseg.2026.2.227

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2026 Vol.36, Issue 2 Preview Page Next Page

Research Article

Comparative Trend Analysis of Deep Disposal Research by SKB and POSIVA Using LDA Topic Modeling LDA 주제 모델링을 활용한 SKB와 POSIVA의 심층 처분 연구 동향 비교 분석

30 June 2026. pp. 227-242

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Abstract

This study quantitatively analyzes the long-term research and development (R&D) trends of two leading companies in deep geological disposal, Sweden’s SKB and Finland’s POSIVA, using latent Dirichlet allocation (LDA) topic modeling combined with structural break analysis. The dataset consists of 2,520 technical report titles from SKB and 1,014 from POSIVA. The LDA results identify nine major R&D topics for SKB and six for POSIVA. This indicates a relatively diversified research portfolio at SKB (top three topics: 49.6% of the total publications) and a more concentrated portfolio at POSIVA (top three topics: 72.2%). Regression analysis of annual topic proportions (i.e., proportion of the total publications) and Wald tests reveal statistically significant (p < 0.05) structural breaks around the years when the firms applied for a construction license (2011 for SKB and 2012 for POSIVA) in five of nine topics for SKB and three of six topics for POSIVA. In particular, hydrogeological modeling R&D undertaken by SKB shows accelerated growth after the license application, whereas underground site characterization R&D undertaken by POSIVA shows a declining trend, indicating contrasting transitions in research focus. In addition, the average inter-topic similarity is lower for SKB (0.12) than for POSIVA (0.34), reflecting differences in the degree of thematic integration associated with multi-site and single-site strategies, respectively. By applying text mining techniques to the field of deep geological disposal, this study visualizes the evolution of research activities undertaken by leading companies in a data-driven manner. The results are expected to provide useful insights for latecomer countries, including the Republic of Korea, in formulating efficient R&D strategies.

Keywords

deep geological disposal

high-level radioactive waste

topic modeling

latent Dirichlet allocation (LDA)

research trend analysis

structural break

본 연구는 심층 처분 분야 선도국인 스웨덴 SKB와 핀란드 POSIVA의 장기 연구개발(R&D) 경향을 정량적으로 비교·분석하기 위해, 잠재 디리클레 할당(latent Dirichlet allocation, LDA) 주제 모델링과 구조적 단절 분석을 적용하였다. 분석 대상은 SKB의 기술보고서 제목 2,520건과 POSIVA의 기술보고서 제목 1,014건이다. LDA 분석 결과, SKB는 9개, POSIVA는 6개의 주요 연구 주제가 도출되었으며, SKB는 상대적으로 분산된 연구 포트폴리오(상위 3개 주제 비중 49.6%)를, POSIVA는 보다 집중된 포트폴리오(상위 3개 주제 비중 72.2%)를 보였다. 연도별 주제 비중에 대한 회귀 분석과 Wald 검정 결과, 건설 허가 신청(SKB: 2011년, POSIVA: 2012년)을 기점으로 SKB는 9개 중 5개 주제, POSIVA는 6개 중 3개 주제에서 통계적으로 유의한 구조적 변화(p < 0.05)가 관찰되었다. 특히 SKB의 수리지질학 모델링 연구는 허가 신청 이후 증가 속도가 가속화된 반면, POSIVA의 현장 특성화 연구는 감소 추세로 전환되어 두 기관 간 상이한 연구 단계 전환 양상이 확인되었다. 또한 주제 간 평균 유사도는 SKB (0.12)가 POSIVA (0.34)보다 낮아, 복수 부지 평가 전략과 단일 부지 집중 전략에 따른 연구 주제 통합도의 차이를 반영하는 것으로 해석되었다. 본 연구는 심층 처분 분야에 텍스트 마이닝 기법을 적용하여 선도국의 연구 진화 과정을 데이터 기반으로 가시화하였으며, 그 결과는 대한민국을 포함한 후발국의 효율적인 R&D 전략 수립을 위한 참고 자료로 활용될 수 있을 것으로 기대된다.

키워드

심층 처분

고준위 방사성폐기물

주제 모델링

잠재 디리클레 할당

연구 경향 분석

구조적 단절

References

Blei, D.M., Ng, A.Y., Jordan, M.I., 2003, Latent Dirichlet allocation, The Journal of Machine Learning Research, 3, 993-1022.

Bouma, G., 2009, Normalized (pointwise) mutual information in collocation extraction, In: Chiarcos, C., Eckart de Castilho, R., Stede, M. (Eds.), From Form to Meaning: Processing Texts Automatically, Proceedings of the Biennial GSCL Conference 2009, Gunter Narr Verlag, Tübingen, 31-40.

Geier, J.E., 2012, Hydrogeological conditions at the Forsmark site, Technical Note 2012:41, Swedish Radiation Safety Authority (SSM), 34p.

Griffiths, T.L., Steyvers, M., 2004, Finding scientific topics, Proceedings of the National Academy of Sciences, 101(suppl 1), 5228-5235.

10.1073/pnas.030775210114872004PMC387300

IAEA (International Atomic Energy Agency), 2011, Geological disposal facilities for radioactive waste, IAEA Safety Standards Series No. SSG-14, 104p.

Kim, T.Y., Lee, H.R., Yang, M.J., 2024, Analysis of research trends in The Journal of Engineering Geology (1991-2024): Latent Dirichlet allocation and network analysis, The Journal of Engineering Geology, 34(3), 429-445 (in Korean with English abstract).

10.9720/KSEG.2024.3.429

Liu, L.L., Zhang, J., Li, J.Z., Huang, F., Wang, L.C., 2022, A bibliometric analysis of the landslide susceptibility research (1999–2021), Geocarto International, 37(26), 14309-14334.

10.1080/10106049.2022.2087753

MOTIE (Ministry of Trade, Industry and Energy), 2016, Basic plan for the management of high-level radioactive waste, 26p (in Korean).

Park, C., Yong, T., 2017, Prospect of Korean nuclear policy change through text mining, Energy Procedia, 128, 72-78.

10.1016/j.egypro.2017.09.017

Posiva Oy, 2015, Posiva is granted construction licence for final disposal facility of spent nuclear fuel, Retrieved from https://www.posiva.fi/en/index/news/pressreleasesstockexchangereleases/2015/posiva_is_granted_construction_licence_for_final_disposal_facility_of_spent_nuclear_fuel.3225.html.

Röder, M., Both, A., Hinneburg, A., 2015, Exploring the space of topic coherence measures, In: Cheng, X., Li, H., Gabrilovich, E., Tang, J. (Eds.), Proceedings of the Eighth ACM International Conference on Web Search and Data Mining, Association for Computing Machinery, New York, NY, 399-408.

10.1145/2684822.2685324

SKB (Swedish Nuclear Fuel and Waste Management Co.), 2022, The government approves SKB’s final repository system, Retrieved from https://skbinternational.se/nyhet/the-government-approves-skbs-final-repository-system/.

STUK (Radiation and Nuclear Safety Authority), 2015, STUK’s statement and safety assessment on the construction of the Olkiluoto encapsulation plant and disposal facility for spent nuclear fuel, STUK-B 196, 91p.

Information

Publisher :Korean Society of Engineering Geology
Publisher(Ko) :대한지질공학회
Journal Title :The Journal of Engineering Geology
Journal Title(Ko) :지질공학
Volume : 36
No :2
Pages :227-242
Received Date : 2026-03-30
Accepted Date : 2026-04-20
DOI :https://doi.org/10.9720/kseg.2026.2.227

The Journal of Engineering Geology ISSN:1226-5268(Print) 2287-7169(Online) 지질공학

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