Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project

Marco Pellegrini (Corresponding author), Luis Enrique Herranz, Martin Sonnenkalb, Terttaliisa Lind, Yu Maruyama, R. Gauntt, Nathan Bixler, A. C. Morreale, K. Dolganov, Tuomo Sevon, Didier Jacquemain, J. H. Song, H. Hoshi, Y. Nishi, Shinya Mizokami

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

The OECD/NEA Benchmark Study at the Accident of Fukushima project (BSAF) has started in 2012 until 2018 as one of the earliest responses to the accident at Fukushima Daiichi with 15 participating organizations out of 10 countries (see list of authors). The project divided into two phases addressed the investigation of the accident at Unit 1, 2 and 3 by Severe Accident (SA) codes until 500 h focusing on thermal-hydraulics, core relocation, Molten Corium Concrete Interaction (MCCI) and Fission Product (FP) release and transport. The objectives of OECD/NEA BSAF were to make up plausible scenarios based primarily on SA forensic analysis, support the decommissioning and inform SA codes modeling. The analysis and comparison among the institutes have brought up vital insights regarding the accident progression identifying periods of core meltdown and relocation, and Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) leakage/failure through the comparison with various plant data (presented in the related papers in the same session). The combination of code and inspections results (muon radiography, PCV inspection) has provided a picture of the current status of the debris distribution and plant status. All units present a large relocation of core materials and all of them present ex-vessel debris with Unit 1 and Unit 3 showing evidences of undergoing timely limited MCCI. Uncertainties have been identified in particular on the time and magnitude of events such as corium relocation inside and from the RPV onto cavity floor, RPV and PCV failure events. Main uncertainties resulting from the project are the large and continuous MCCI progression predicted by basically all the SA codes and the leak pathways from RPV to PCV and PCV to reactor building and environment. The OECD/NEA BSAF project represents a pioneering exercise which has set the basis and provided lessons learned not only for code improvement but also for the development of new related projects to investigate in details further aspects of the Fukushima Daiichi accident.
Original languageEnglish
Title of host publicationProceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18
PublisherAmerican Nuclear Society ANS
Pages1147-1162
Number of pages16
ISBN (Electronic)978-0-89448-767-5
Publication statusPublished - 2019
MoE publication typeA4 Article in a conference publication
Event18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019 - Portland, United States
Duration: 18 Aug 201923 Aug 2019

Conference

Conference18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019
Abbreviated titleNURETH-18
CountryUnited States
CityPortland
Period18/08/1923/08/19

Fingerprint

Accidents
Containment vessels
Relocation
Pressure vessels
Molten materials
Concretes
Debris
Core meltdown
Uncertainty
Inspection
Codes (standards)
Fission products
Radiography
Hydraulics

Keywords

  • BSAF
  • Fukushima Daiichi NPS accident
  • OECD/NEA
  • SA code

Cite this

Pellegrini, M., Herranz, L. E., Sonnenkalb, M., Lind, T., Maruyama, Y., Gauntt, R., ... Mizokami, S. (2019). Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project. In Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18 (pp. 1147-1162). American Nuclear Society ANS.
Pellegrini, Marco ; Herranz, Luis Enrique ; Sonnenkalb, Martin ; Lind, Terttaliisa ; Maruyama, Yu ; Gauntt, R. ; Bixler, Nathan ; Morreale, A. C. ; Dolganov, K. ; Sevon, Tuomo ; Jacquemain, Didier ; Song, J. H. ; Hoshi, H. ; Nishi, Y. ; Mizokami, Shinya. / Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project. Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18. American Nuclear Society ANS, 2019. pp. 1147-1162
@inproceedings{75822cea79a249c58f56d023791a6197,
title = "Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project",
abstract = "The OECD/NEA Benchmark Study at the Accident of Fukushima project (BSAF) has started in 2012 until 2018 as one of the earliest responses to the accident at Fukushima Daiichi with 15 participating organizations out of 10 countries (see list of authors). The project divided into two phases addressed the investigation of the accident at Unit 1, 2 and 3 by Severe Accident (SA) codes until 500 h focusing on thermal-hydraulics, core relocation, Molten Corium Concrete Interaction (MCCI) and Fission Product (FP) release and transport. The objectives of OECD/NEA BSAF were to make up plausible scenarios based primarily on SA forensic analysis, support the decommissioning and inform SA codes modeling. The analysis and comparison among the institutes have brought up vital insights regarding the accident progression identifying periods of core meltdown and relocation, and Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) leakage/failure through the comparison with various plant data (presented in the related papers in the same session). The combination of code and inspections results (muon radiography, PCV inspection) has provided a picture of the current status of the debris distribution and plant status. All units present a large relocation of core materials and all of them present ex-vessel debris with Unit 1 and Unit 3 showing evidences of undergoing timely limited MCCI. Uncertainties have been identified in particular on the time and magnitude of events such as corium relocation inside and from the RPV onto cavity floor, RPV and PCV failure events. Main uncertainties resulting from the project are the large and continuous MCCI progression predicted by basically all the SA codes and the leak pathways from RPV to PCV and PCV to reactor building and environment. The OECD/NEA BSAF project represents a pioneering exercise which has set the basis and provided lessons learned not only for code improvement but also for the development of new related projects to investigate in details further aspects of the Fukushima Daiichi accident.",
keywords = "BSAF, Fukushima Daiichi NPS accident, OECD/NEA, SA code",
author = "Marco Pellegrini and Herranz, {Luis Enrique} and Martin Sonnenkalb and Terttaliisa Lind and Yu Maruyama and R. Gauntt and Nathan Bixler and Morreale, {A. C.} and K. Dolganov and Tuomo Sevon and Didier Jacquemain and Song, {J. H.} and H. Hoshi and Y. Nishi and Shinya Mizokami",
year = "2019",
language = "English",
pages = "1147--1162",
booktitle = "Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18",
publisher = "American Nuclear Society ANS",
address = "United States",

}

Pellegrini, M, Herranz, LE, Sonnenkalb, M, Lind, T, Maruyama, Y, Gauntt, R, Bixler, N, Morreale, AC, Dolganov, K, Sevon, T, Jacquemain, D, Song, JH, Hoshi, H, Nishi, Y & Mizokami, S 2019, Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project. in Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18. American Nuclear Society ANS, pp. 1147-1162, 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019, Portland, United States, 18/08/19.

Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project. / Pellegrini, Marco (Corresponding author); Herranz, Luis Enrique; Sonnenkalb, Martin; Lind, Terttaliisa; Maruyama, Yu; Gauntt, R.; Bixler, Nathan; Morreale, A. C.; Dolganov, K.; Sevon, Tuomo; Jacquemain, Didier; Song, J. H.; Hoshi, H.; Nishi, Y.; Mizokami, Shinya.

Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18. American Nuclear Society ANS, 2019. p. 1147-1162.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project

AU - Pellegrini, Marco

AU - Herranz, Luis Enrique

AU - Sonnenkalb, Martin

AU - Lind, Terttaliisa

AU - Maruyama, Yu

AU - Gauntt, R.

AU - Bixler, Nathan

AU - Morreale, A. C.

AU - Dolganov, K.

AU - Sevon, Tuomo

AU - Jacquemain, Didier

AU - Song, J. H.

AU - Hoshi, H.

AU - Nishi, Y.

AU - Mizokami, Shinya

PY - 2019

Y1 - 2019

N2 - The OECD/NEA Benchmark Study at the Accident of Fukushima project (BSAF) has started in 2012 until 2018 as one of the earliest responses to the accident at Fukushima Daiichi with 15 participating organizations out of 10 countries (see list of authors). The project divided into two phases addressed the investigation of the accident at Unit 1, 2 and 3 by Severe Accident (SA) codes until 500 h focusing on thermal-hydraulics, core relocation, Molten Corium Concrete Interaction (MCCI) and Fission Product (FP) release and transport. The objectives of OECD/NEA BSAF were to make up plausible scenarios based primarily on SA forensic analysis, support the decommissioning and inform SA codes modeling. The analysis and comparison among the institutes have brought up vital insights regarding the accident progression identifying periods of core meltdown and relocation, and Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) leakage/failure through the comparison with various plant data (presented in the related papers in the same session). The combination of code and inspections results (muon radiography, PCV inspection) has provided a picture of the current status of the debris distribution and plant status. All units present a large relocation of core materials and all of them present ex-vessel debris with Unit 1 and Unit 3 showing evidences of undergoing timely limited MCCI. Uncertainties have been identified in particular on the time and magnitude of events such as corium relocation inside and from the RPV onto cavity floor, RPV and PCV failure events. Main uncertainties resulting from the project are the large and continuous MCCI progression predicted by basically all the SA codes and the leak pathways from RPV to PCV and PCV to reactor building and environment. The OECD/NEA BSAF project represents a pioneering exercise which has set the basis and provided lessons learned not only for code improvement but also for the development of new related projects to investigate in details further aspects of the Fukushima Daiichi accident.

AB - The OECD/NEA Benchmark Study at the Accident of Fukushima project (BSAF) has started in 2012 until 2018 as one of the earliest responses to the accident at Fukushima Daiichi with 15 participating organizations out of 10 countries (see list of authors). The project divided into two phases addressed the investigation of the accident at Unit 1, 2 and 3 by Severe Accident (SA) codes until 500 h focusing on thermal-hydraulics, core relocation, Molten Corium Concrete Interaction (MCCI) and Fission Product (FP) release and transport. The objectives of OECD/NEA BSAF were to make up plausible scenarios based primarily on SA forensic analysis, support the decommissioning and inform SA codes modeling. The analysis and comparison among the institutes have brought up vital insights regarding the accident progression identifying periods of core meltdown and relocation, and Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) leakage/failure through the comparison with various plant data (presented in the related papers in the same session). The combination of code and inspections results (muon radiography, PCV inspection) has provided a picture of the current status of the debris distribution and plant status. All units present a large relocation of core materials and all of them present ex-vessel debris with Unit 1 and Unit 3 showing evidences of undergoing timely limited MCCI. Uncertainties have been identified in particular on the time and magnitude of events such as corium relocation inside and from the RPV onto cavity floor, RPV and PCV failure events. Main uncertainties resulting from the project are the large and continuous MCCI progression predicted by basically all the SA codes and the leak pathways from RPV to PCV and PCV to reactor building and environment. The OECD/NEA BSAF project represents a pioneering exercise which has set the basis and provided lessons learned not only for code improvement but also for the development of new related projects to investigate in details further aspects of the Fukushima Daiichi accident.

KW - BSAF

KW - Fukushima Daiichi NPS accident

KW - OECD/NEA

KW - SA code

UR - http://www.scopus.com/inward/record.url?scp=85073713743&partnerID=8YFLogxK

M3 - Conference article in proceedings

SP - 1147

EP - 1162

BT - Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18

PB - American Nuclear Society ANS

ER -

Pellegrini M, Herranz LE, Sonnenkalb M, Lind T, Maruyama Y, Gauntt R et al. Main Findings, Remaining Uncertainties and Lessons Learned from the OECD/NEA BSAF Project. In Proceedings of the 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-18. American Nuclear Society ANS. 2019. p. 1147-1162