Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100

Yujian Wang; Haoli Wang; Shihao Wu; Yapei Zhang; Wenxi Tian; Suizheng Qiu; G. H. Su

doi:10.1007/978-981-95-3237-7_42

Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100

Yujian Wang
, Haoli Wang
, Shihao Wu
, Yapei Zhang
, Wenxi Tian
, Suizheng Qiu
, G. H. Su

School of Energy and Power Engineering

Xi'an Jiaotong University

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

Small Modular Reactors (SMRs), exemplified by China’s third-generation ACP100 design, integrate advanced safety features such as passive residual heat removal (PRHRS) and safety injection systems. A Station Blackout (SBO)—loss of offsite power, turbine trip, and emergency AC power failure—can escalate into severe accidents like core meltdown. This study evaluates the ACP100’s response to an SBO combined with PRHRS failure, focusing on the timing of squib valve activation to mitigate primary circuit pressure and replenish coolant. Using severe accident analysis software, variations in maximum cladding temperature were assessed with 1200 K as the failure threshold. Key findings: (1) Squib valve opening rapidly reduces cladding temperature by restoring coolant inventory; (2) Premature valve activation worsens accident severity; (3) Delayed valve opening (before cladding reaches 1200 K) prolongs temperature rise and better preserves cladding integrity. These insights highlight the critical balance between early intervention and delayed valve operation to optimize accident mitigation in SMRs.

Original language	English
Title of host publication	Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events
Editors	Sichao Tan, Weiqiang Xu, Yanyan Zhu
Publisher	Springer Science and Business Media Deutschland GmbH
Pages	513-522
Number of pages	10
ISBN (Print)	9789819532360
DOIs	https://doi.org/10.1007/978-981-95-3237-7_42
State	Published - 2026
Event	32nd International Conference on Nuclear Engineering, ICONE 2025 - Weihai, China Duration: 22 Jun 2025 → 26 Jun 2025

Publication series

Name	Springer Proceedings in Physics
Volume	334 SPPHY
ISSN (Print)	0930-8989
ISSN (Electronic)	1867-4941

Conference

Conference	32nd International Conference on Nuclear Engineering, ICONE 2025
Country/Territory	China
City	Weihai
Period	22/06/25 → 26/06/25

Keywords

ACP100
Numerical analysis
SBO
Small Modular Reactor (SMR)
Squib valve

Access to Document

10.1007/978-981-95-3237-7_42

Cite this

Wang, Y., Wang, H., Wu, S., Zhang, Y., Tian, W., Qiu, S., & Su, G. H. (2026). Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100. In S. Tan, W. Xu, & Y. Zhu (Eds.), Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events (pp. 513-522). (Springer Proceedings in Physics; Vol. 334 SPPHY). Springer Science and Business Media Deutschland GmbH. https://doi.org/10.1007/978-981-95-3237-7_42

Wang, Yujian ; Wang, Haoli ; Wu, Shihao et al. / Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100. Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events. editor / Sichao Tan ; Weiqiang Xu ; Yanyan Zhu. Springer Science and Business Media Deutschland GmbH, 2026. pp. 513-522 (Springer Proceedings in Physics).

@inproceedings{12e883811c374f6e92f1e1e2620fd3a1,

title = "Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100",

abstract = "Small Modular Reactors (SMRs), exemplified by China{\textquoteright}s third-generation ACP100 design, integrate advanced safety features such as passive residual heat removal (PRHRS) and safety injection systems. A Station Blackout (SBO){\textemdash}loss of offsite power, turbine trip, and emergency AC power failure{\textemdash}can escalate into severe accidents like core meltdown. This study evaluates the ACP100{\textquoteright}s response to an SBO combined with PRHRS failure, focusing on the timing of squib valve activation to mitigate primary circuit pressure and replenish coolant. Using severe accident analysis software, variations in maximum cladding temperature were assessed with 1200 K as the failure threshold. Key findings: (1) Squib valve opening rapidly reduces cladding temperature by restoring coolant inventory; (2) Premature valve activation worsens accident severity; (3) Delayed valve opening (before cladding reaches 1200 K) prolongs temperature rise and better preserves cladding integrity. These insights highlight the critical balance between early intervention and delayed valve operation to optimize accident mitigation in SMRs.",

keywords = "ACP100, Numerical analysis, SBO, Small Modular Reactor (SMR), Squib valve",

author = "Yujian Wang and Haoli Wang and Shihao Wu and Yapei Zhang and Wenxi Tian and Suizheng Qiu and Su, \{G. H.\}",

note = "Publisher Copyright: {\textcopyright} The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2026.; 32nd International Conference on Nuclear Engineering, ICONE 2025 ; Conference date: 22-06-2025 Through 26-06-2025",

year = "2026",

doi = "10.1007/978-981-95-3237-7\_42",

language = "英语",

isbn = "9789819532360",

series = "Springer Proceedings in Physics",

publisher = "Springer Science and Business Media Deutschland GmbH",

pages = "513--522",

editor = "Sichao Tan and Weiqiang Xu and Yanyan Zhu",

booktitle = "Proceedings of the 32nd International Conference on Nuclear Engineering{\textemdash} Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events",

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Wang, Y, Wang, H, Wu, S, Zhang, Y, Tian, W, Qiu, S & Su, GH 2026, Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100. in S Tan, W Xu & Y Zhu (eds), Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events. Springer Proceedings in Physics, vol. 334 SPPHY, Springer Science and Business Media Deutschland GmbH, pp. 513-522, 32nd International Conference on Nuclear Engineering, ICONE 2025, Weihai, China, 22/06/25. https://doi.org/10.1007/978-981-95-3237-7_42

Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100. / Wang, Yujian; Wang, Haoli; Wu, Shihao et al.
Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events. ed. / Sichao Tan; Weiqiang Xu; Yanyan Zhu. Springer Science and Business Media Deutschland GmbH, 2026. p. 513-522 (Springer Proceedings in Physics; Vol. 334 SPPHY).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100

AU - Wang, Yujian

AU - Wang, Haoli

AU - Wu, Shihao

AU - Zhang, Yapei

AU - Tian, Wenxi

AU - Qiu, Suizheng

AU - Su, G. H.

N1 - Publisher Copyright: © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2026.

PY - 2026

Y1 - 2026

N2 - Small Modular Reactors (SMRs), exemplified by China’s third-generation ACP100 design, integrate advanced safety features such as passive residual heat removal (PRHRS) and safety injection systems. A Station Blackout (SBO)—loss of offsite power, turbine trip, and emergency AC power failure—can escalate into severe accidents like core meltdown. This study evaluates the ACP100’s response to an SBO combined with PRHRS failure, focusing on the timing of squib valve activation to mitigate primary circuit pressure and replenish coolant. Using severe accident analysis software, variations in maximum cladding temperature were assessed with 1200 K as the failure threshold. Key findings: (1) Squib valve opening rapidly reduces cladding temperature by restoring coolant inventory; (2) Premature valve activation worsens accident severity; (3) Delayed valve opening (before cladding reaches 1200 K) prolongs temperature rise and better preserves cladding integrity. These insights highlight the critical balance between early intervention and delayed valve operation to optimize accident mitigation in SMRs.

AB - Small Modular Reactors (SMRs), exemplified by China’s third-generation ACP100 design, integrate advanced safety features such as passive residual heat removal (PRHRS) and safety injection systems. A Station Blackout (SBO)—loss of offsite power, turbine trip, and emergency AC power failure—can escalate into severe accidents like core meltdown. This study evaluates the ACP100’s response to an SBO combined with PRHRS failure, focusing on the timing of squib valve activation to mitigate primary circuit pressure and replenish coolant. Using severe accident analysis software, variations in maximum cladding temperature were assessed with 1200 K as the failure threshold. Key findings: (1) Squib valve opening rapidly reduces cladding temperature by restoring coolant inventory; (2) Premature valve activation worsens accident severity; (3) Delayed valve opening (before cladding reaches 1200 K) prolongs temperature rise and better preserves cladding integrity. These insights highlight the critical balance between early intervention and delayed valve operation to optimize accident mitigation in SMRs.

KW - ACP100

KW - Numerical analysis

KW - SBO

KW - Small Modular Reactor (SMR)

KW - Squib valve

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DO - 10.1007/978-981-95-3237-7_42

M3 - 会议稿件

AN - SCOPUS:105045840920

SN - 9789819532360

T3 - Springer Proceedings in Physics

SP - 513

EP - 522

BT - Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events

A2 - Tan, Sichao

A2 - Xu, Weiqiang

A2 - Zhu, Yanyan

PB - Springer Science and Business Media Deutschland GmbH

T2 - 32nd International Conference on Nuclear Engineering, ICONE 2025

Y2 - 22 June 2025 through 26 June 2025

ER -

Wang Y, Wang H, Wu S, Zhang Y, Tian W, Qiu S et al. Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100. In Tan S, Xu W, Zhu Y, editors, Proceedings of the 32nd International Conference on Nuclear Engineering— Volume 8, ICONE 2025- Nuclear Codes and Standards, Licensing and Regulation, Mitigation Strategy for Beyond Design Basic Events. Springer Science and Business Media Deutschland GmbH. 2026. p. 513-522. (Springer Proceedings in Physics). doi: 10.1007/978-981-95-3237-7_42

Study on the Impact of Squib Valve Opening Time on Maximum Temperature of Cladding During a SBO Accident in the ACP100

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