Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2018, Vol. 29 ›› Issue (3): 33 doi: 10.1007/s41365-018-0372-6

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Neutronic design investigation of a liquid injection based second shutdown system for a typical research reactor using MCNPX

Ehsan Boustani, Mostafa Hassanzadeh   

  1. Nuclear Science and Technology Research Institute (NSTRI), Reactor and Nuclear Safety School, Tehran 14399-51113, Iran
  • Contact: Ehsan Boustani E-mail:eboustani@aeoi.org.ir
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Ehsan Boustani, Mostafa Hassanzadeh. Neutronic design investigation of a liquid injection based second shutdown system for a typical research reactor using MCNPX.Nuclear Science and Techniques, 2018, 29(3): 33     doi: 10.1007/s41365-018-0372-6
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Abstract:

Safety systems, built on state-of-the-art technology, are essential for achieving acceptable levels of plant safety to minimize hazards to the reactor and the general public. The second shutdown system (SSS) as an engineered safety feature and a part of the reactor protection system (RPS) is a means for rapidly shutting down a nuclear reactor, keeping it in a subcritical state and serving as a backup to the first shutdown system (FSS). In this research, one SSS with two types of optimum chamber designs is proposed that take into account the main current characteristic features of the Tehran research reactor with improvements over earlier designs. They are based on a liquid neutron absorber injection that is preferably different, diverse, and independent from the FSS based on the rod drop mechanism. The major design characteristics of this SSS with two different chambers were investigated using MCNPX 2.6.0 code. The performed calculations showed that the designed SSS is a reliable shutdown system, assuring an appropriate shutdown margin and injection time, with no significant effects on the effective delayed neutron fraction while causing minimal variations to the core structure. Further, the reasonable financial cost and the prolongation of the operation cycle are additional advantages of this design.

Key words: Tehran research reactor, Second shutdown system, Nuclear safety, Design criteria, MCNPX code