scholarly journals Neutronic analysis of control rod effect on safety parameters in Tehran Research Reactor

2018 ◽  
Vol 50 (7) ◽  
pp. 1017-1023 ◽  
Author(s):  
Mina Torabi ◽  
A. Lashkari ◽  
Seyed Farhad Masoudi ◽  
Somayeh Bagheri
Author(s):  
J. Jafari ◽  
M. K. Firuzjaee ◽  
S. Khakshournia ◽  
K. Sepanloo ◽  
F. D’Auria

The aim of this study is to evaluate the thermal hydraulic parameters such as, Minimum DNBR, fuel, clad and coolant temperatures of the Tehran Research Reactor (TRR) core in order to assure that the thermal limitations are not exceeded at full power and steady-state and the loss-of-flow accident (LOFA) operating conditions and the existing design is adequate to assure that the consequences from this anticipated occurrence does not lead to a severe accident. The PARET and TRANS computer codes were used to analysis thermal-hydraulic and safety parameters under study steady-state conditions. Furthermore the LOFA as a consequence of two type of transients are analyzed; one related to main cooling pump failure accident (slow LOFA), and the other related to accidentally opening the flapper valve whereas the main cooling pump is in working (fast LOFA). The steady-state analysis involves the determination of the departure from nucleate boiling ratio (DNBR), the temperatures profile, heat flux across the hottest channel and etc. The LOFA analysis involves the power and coolant flow rate, the fuel centerline, clad surface and coolant outlet temperatures, and the occurring of coolant flow reversal.


Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 367-371 ◽  
Author(s):  
Saadou Aldawahra ◽  
Kassem Khattab ◽  
Gorge Saba

Abstract Comparative studies for conversion of the fuel from HEU to LEU in the miniature neutron source reactor (MNSR) have been performed using the MCNP4C code. The HEU fuel (UAl4-Al, 90% enriched with Al clad) and LEU (UO2 12.6% enriched with zircaloy-4 alloy clad) cores have been analyzed in this study. The existing HEU core of MNSR was analyzed to validate the neutronic model of reactor, while the LEU core was studied to prove the possibility of fuel conversion of the existing HEU core. The proposed LEU core contained the same number of fuel pins as the HEU core. All other structure materials and dimensions of HEU and LEU cores were the same except the increase in the radius of control rod material from 0.195 to 0.205 cm and keeping the outer diameter of the control rod unchanged in the LEU core. The effective multiplication factor (keff), excess reactivity (ρex), control rod worth (CRW), shutdown margin (SDM), safety reactivity factor (SRF), delayed neutron fraction (βeff) and the neutron fluxes in the irradiation tubes for the existing and the potential LEU fuel were investigated. The results showed that the safety parameters and the neutron fluxes in the irradiation tubes of the LEU fuels were in good agreements with the HEU results. Therefore, the LEU fuel was validated to be a suitable choice for fuel conversion of the MNSR in the future.


2016 ◽  
Vol 58 (9) ◽  
pp. 763-766 ◽  
Author(s):  
Mohammad Hosein Choopan Dastjerdi ◽  
Hossein Khalafi ◽  
Yaser Kasesaz ◽  
Amir Movafeghi

Author(s):  
Nicholas J. Wheeler

This chapter examines the attempts by the first Obama Administration to reach out to Iran in an effort to build trust. It traces the failure of Obama’s diplomatic efforts to secure any reciprocation from Iranian leaders. The lack of reciprocation shows the problem of accurate signal interpretation when there is no trust. It focuses on the negotiations in 2009–10 over limiting Iran’s supply of nuclear fuel in return for refuelling the Tehran Research Reactor. The chapter argues these negotiations failed because of the lack of trust. What makes this case so important is that there was no face-to-face interaction, which this book argues is critical to the development of interpersonal trust and accurate signal interpretation.


2013 ◽  
Vol 28 (1) ◽  
pp. 18-24
Author(s):  
Sayedeh Mirmohammadi ◽  
Morteza Gharib ◽  
Parnian Ebrahimzadeh ◽  
Reza Amrollahi

A hot water layer system (HWLS) is a novel system for reducing radioactivity under research reactor containment. This system is particularly useful in pool-type research reactors or other light water reactors with an open pool surface. The main purpose of a HWLS is to provide more protection for operators and reactor personnel against undesired doses due to the radio- activity of the primary loop. This radioactivity originates mainly from the induced radioactivity contained within the cooling water or probable minute leaks of fuel elements. More importantly, the bothersome radioactivity is progressively proportional to reactor power and, thus, the HWLS is a partial solution for mitigating such problems when power upgrading is planned. Following a series of tests and checks for different parameters, a HWLS has been built and put into operation at the Tehran research reactor in 2009. It underwent a series of comprehensive tests for a period of 6 months. Within this time-frame, it was realized that the HWLS could provide a better protection for reactor personnel against prevailing radiation under containment. The system is especially suitable in cases of abnormality, e. g. the spread of fission products due to fuel failure, because it prevents the mixing of pollutants developed deep in the pool with the upper layer and thus mitigates widespread leakage of radioactivity.


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