Experience from Level 2 Site Risk Analysis for Nordic Power Plants

Jan-Erik Holmberg; Stefan Authén; Ola Bäckström; He Xuhong; Salvatore Massaiu; Tero Tyrväinen

doi:10.3850/978-981-11-2724-3_0276-cd

Experience from Level 2 Site Risk Analysis for Nordic Power Plants

Jan-Erik Holmberg, Stefan Authén, Ola Bäckström, He Xuhong, Salvatore Massaiu, Tero Tyrväinen

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review

Abstract

The objective with the SITRON (SITe Risk On Nuclear installations) project has been to search for practical approaches for Nordic utilities to assess the site level risk. This paper presents the findings from the performance of level 2 PSA, i.e., the assessment of radioactive release risk from multiple units. Qualitatively, a multi-unit level 1 and 2 PSA are similar in terms of identifying dependencies. Level 2 PSA may bring some additional dependencies that are not relevant for level 1 PSA. Quantitatively, the difference in the used risk metrics can have some practical implications. In level 1 PSA, risk metrics are the frequencies of combinations of core damages (one, two, ..., all units). In level 2 PSA, risk metric is the frequency of a certain release category (small, large, early, late), which is determined by the aggregated release rather than number of releases. The need to quantify various accident sequences is thus much dependent on the applied safety goal for level 2 PSA. Further, pilot studies indicate that inter-unit dependencies in level 2 safety functions have less influence on results than inter-unit dependencies in level 1 safety functions.

Original language	English
Title of host publication	Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019
Editors	Michael Beer, Enrico Zio
Place of Publication	Singapore
Publisher	European Safety and Reliability Association (ESRA)
Pages	3790-3797
ISBN (Electronic)	978-981-11-2724-3
DOIs	https://doi.org/10.3850/978-981-11-2724-3_0276-cd
Publication status	Published - Sept 2019
MoE publication type	A4 Article in a conference publication
Event	29th European Safety and Reliability Conference, ESREL 2019 - Welfenschloss, Hannover, Germany Duration: 22 Sept 2019 → 26 Sept 2019 https://esrel2019.org/#/

Conference

Conference	29th European Safety and Reliability Conference, ESREL 2019
Country/Territory	Germany
City	Hannover
Period	22/09/19 → 26/09/19
Internet address	https://esrel2019.org/#/

Funding

The work has been co-financed by The Finnish Research Programme on Nuclear Power Plant Safety SAFIR2018, Nordic PSA Group (Forsmark Kraftgrupp AB, Ringhals AB, Swedish Radiation Safety Authority (SSM)), and Nordic nuclear safety research (NKS). NKS conveys its gratitude to all organizations and persons who by means of financial support or contributions in kind have made the work presented in this report possible.

Keywords

site risk analysis
nuclear power plant
level 2 PSA
probabilistic safety assessment
probabilistic risk analysis
multi-unit
severe accident
risk metrics
human reliability analysis

Access to Document

10.3850/978-981-11-2724-3_0276-cd

Cite this

Holmberg, J.-E., Authén, S., Bäckström, O., Xuhong, H., Massaiu, S., & Tyrväinen, T. (2019). Experience from Level 2 Site Risk Analysis for Nordic Power Plants. In M. Beer, & E. Zio (Eds.), Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019 (pp. 3790-3797). Article 0276 European Safety and Reliability Association (ESRA). https://doi.org/10.3850/978-981-11-2724-3_0276-cd

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title = "Experience from Level 2 Site Risk Analysis for Nordic Power Plants",

abstract = "The objective with the SITRON (SITe Risk On Nuclear installations) project has been to search for practical approaches for Nordic utilities to assess the site level risk. This paper presents the findings from the performance of level 2 PSA, i.e., the assessment of radioactive release risk from multiple units. Qualitatively, a multi-unit level 1 and 2 PSA are similar in terms of identifying dependencies. Level 2 PSA may bring some additional dependencies that are not relevant for level 1 PSA. Quantitatively, the difference in the used risk metrics can have some practical implications. In level 1 PSA, risk metrics are the frequencies of combinations of core damages (one, two, ..., all units). In level 2 PSA, risk metric is the frequency of a certain release category (small, large, early, late), which is determined by the aggregated release rather than number of releases. The need to quantify various accident sequences is thus much dependent on the applied safety goal for level 2 PSA. Further, pilot studies indicate that inter-unit dependencies in level 2 safety functions have less influence on results than inter-unit dependencies in level 1 safety functions.",

keywords = "site risk analysis, nuclear power plant, level 2 PSA, probabilistic safety assessment, probabilistic risk analysis, multi-unit, severe accident, risk metrics, human reliability analysis",

author = "Jan-Erik Holmberg and Stefan Auth{\'e}n and Ola B{\"a}ckstr{\"o}m and He Xuhong and Salvatore Massaiu and Tero Tyrv{\"a}inen",

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Holmberg, J-E, Authén, S, Bäckström, O, Xuhong, H, Massaiu, S & Tyrväinen, T 2019, Experience from Level 2 Site Risk Analysis for Nordic Power Plants. in M Beer & E Zio (eds), Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019., 0276, European Safety and Reliability Association (ESRA), Singapore, pp. 3790-3797, 29th European Safety and Reliability Conference, ESREL 2019, Hannover, Germany, 22/09/19. https://doi.org/10.3850/978-981-11-2724-3_0276-cd

Experience from Level 2 Site Risk Analysis for Nordic Power Plants. / Holmberg, Jan-Erik; Authén, Stefan; Bäckström, Ola et al.
Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019. ed. / Michael Beer; Enrico Zio. Singapore: European Safety and Reliability Association (ESRA), 2019. p. 3790-3797 0276.

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review

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AU - Tyrväinen, Tero

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N2 - The objective with the SITRON (SITe Risk On Nuclear installations) project has been to search for practical approaches for Nordic utilities to assess the site level risk. This paper presents the findings from the performance of level 2 PSA, i.e., the assessment of radioactive release risk from multiple units. Qualitatively, a multi-unit level 1 and 2 PSA are similar in terms of identifying dependencies. Level 2 PSA may bring some additional dependencies that are not relevant for level 1 PSA. Quantitatively, the difference in the used risk metrics can have some practical implications. In level 1 PSA, risk metrics are the frequencies of combinations of core damages (one, two, ..., all units). In level 2 PSA, risk metric is the frequency of a certain release category (small, large, early, late), which is determined by the aggregated release rather than number of releases. The need to quantify various accident sequences is thus much dependent on the applied safety goal for level 2 PSA. Further, pilot studies indicate that inter-unit dependencies in level 2 safety functions have less influence on results than inter-unit dependencies in level 1 safety functions.

AB - The objective with the SITRON (SITe Risk On Nuclear installations) project has been to search for practical approaches for Nordic utilities to assess the site level risk. This paper presents the findings from the performance of level 2 PSA, i.e., the assessment of radioactive release risk from multiple units. Qualitatively, a multi-unit level 1 and 2 PSA are similar in terms of identifying dependencies. Level 2 PSA may bring some additional dependencies that are not relevant for level 1 PSA. Quantitatively, the difference in the used risk metrics can have some practical implications. In level 1 PSA, risk metrics are the frequencies of combinations of core damages (one, two, ..., all units). In level 2 PSA, risk metric is the frequency of a certain release category (small, large, early, late), which is determined by the aggregated release rather than number of releases. The need to quantify various accident sequences is thus much dependent on the applied safety goal for level 2 PSA. Further, pilot studies indicate that inter-unit dependencies in level 2 safety functions have less influence on results than inter-unit dependencies in level 1 safety functions.

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Y2 - 22 September 2019 through 26 September 2019

ER -

Holmberg JE, Authén S, Bäckström O, Xuhong H, Massaiu S, Tyrväinen T. Experience from Level 2 Site Risk Analysis for Nordic Power Plants. In Beer M, Zio E, editors, Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019. Singapore: European Safety and Reliability Association (ESRA). 2019. p. 3790-3797. 0276 doi: 10.3850/978-981-11-2724-3_0276-cd

Experience from Level 2 Site Risk Analysis for Nordic Power Plants

Abstract

Conference

Funding

Keywords

Access to Document

Other files and links

Fingerprint

SAFIR 2018: The Finnish Research Programme on Nuclear Power Plant Safety 2015 - 2018

Cite this

Experience from Level 2 Site Risk Analysis for Nordic Power Plants

Abstract

Conference

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

SAFIR 2018: The Finnish Research Programme on Nuclear Power Plant Safety 2015 - 2018

Cite this