Radiation Physics and Engineering
A peer-reviewed journal published by K. N. Toosi University of Technology

RELAP5 code investigation on operational characteristics of passive siphon breaker line in research reactors under LOCA conditions

Document Type : Research Article

Authors

Ali Shahabinejad 1, 2
Aref Rahimian 1
Masoud Aminmozafari 1
Mohammadmahdi Eghbal 1

1 Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, 1439951113, Tehran, Iran

2 Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, 7193616548, Shiraz, Iran

https://doi.org/10.22034/rpe.2024.471407.1231
Abstract
Currently, passive safety systems are critical for enhancing nuclear reactor safety and dependability. To limit the chance of the core being uncovered in pool-type research reactors, a siphon pipe with a penetration in the pool wall higher than the core level can be used as the pool outlet pipe. Using a siphon breaker as a passive safety system is vital. The hydraulic study of the siphon breaker line passive safety system for a pool-type research reactor is carried out using the RELAP5 code. The hydraulic analysis and modeling are carried out on a 16-inch coolant outlet siphon pipe, taking into account 16-inch and 8-inch break diameters, as well as siphon breaker line diameters of 2, 2.5, 3, and 4 inches. As a consequence, the undershooting height for a 16-inch break and a 4-inch siphon breaker line is -36.7 cm. The undershooting height is -51.4 cm when using an 8-inch break and a 2-inch siphon breaker line. Compared with the findings to the reference experimental data, the largest difference is -3.1 cm and the smallest difference is -0.1 cm. The findings obtained indicate a substantial agreement between the simulated and experimental results.

Highlights

  • The heterogeneous solution approach has fewer errors and is more accurate than the homogeneous solution.
  • The amount of UH is increased with the increase of break size or the decrease of the size of the siphon breaker line.
  • The RELAP5/Mod3.2ai thermohydraulic code is capable of modeling this kind of accident on a large scale.
  • The simulation results showed an acceptable degree of conformance with the experimental data

Keywords

Breaker
Passive
RELAP5
SBL
LOCA
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Radiation Physics and Engineering
Volume 6, Issue 1
Winter 2025
Pages 1-8

  • Receive Date 03 August 2024
  • Revise Date 31 August 2024
  • Accept Date 31 August 2024

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