Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Measurement of power reactivity coefficients using In-hour equation in Tehran Research Reactor

Document Type : Research Paper

Authors

A. lashkari 1
M. Alikhani 2
R. Ahangari 1
R. Saberi 1

1 Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 14155-1339, Tehran- Iran

2 Faculty of engineering Islamic azad university, research and science branch, P.O.Box: 14515-757, Tehran- Iran

https://doi.org/10.24200/nst.2021.1310
Abstract
This paper uses a new technique to measure the power and temperature reactivity coefficients. In this method, the core reactivity changes due to the modifications in the power or temperature directly. The values of these coefficients are independent of the worth and positions of the control rods. This method is completely new and no report or article has been reported in this field. Increasing the core power causes negative reactivity due to the temperature feedback, and cooling the core makes positive reactivity. In this method, TRR is critical at constant power in natural cooling mode. After getting a relative equilibrium in inlet and outlet coolant temperature, the fly valve of the reactor is opened, so that the cooling mode of TRR changes from natural to the forced mode. Obviously, by establishing a cooling flow in a short time, all produced heat in the natural mode is removed by forced, then a positive reactivity is inserted. As a result, the positive reactivity increases the reactor power. By measuring the doubling time of the power growing, the value of the inserted reactivity is obtained using inhour equation in each initial power. The mean value of the power reactivity coefficient in TRR is about 1.02 pcm / kW that agrees with both results of the previous and recent simulations.

Keywords

Research reactors
power reactivity coefficient
Temperature reactivity coefficients
natural cooling
MTR_PC code
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6.   AEOI,‌ Nuclear Reactor and Safety School, TRR experiments Guide

 

 

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8.  Pablo Abbate ,INVAP, CONVEX V 3.40,.,‌ A program for thermal-hydraulic analysis of a MTR-type core in natural circulation regime. (2002)

 

9.   Yari, Maedeh, et al,‌ Three dimensional analysis of temperature effect on control rod worth in TRR. Nuclear Engineering and Technology 50.8 1266-1276. (2018):

 

‌10.  T‌. M‌A‌K‌M‌A  et al. Validation of the Stable Period Method Against Analytic Solution – IGORR conference, 2017
1.   E. Simon,‌ MTR-type nuclear reactor safety analysis ,‌A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirements for the Degree Doctor of philosophy‌, McMaster University February (2006)‌.
 
2.   P. Souza, et al.,‌ reactivity power coefficient determination of the ipr-r1 triga reactor‌. In 3rd world triga users conference august (2009).
 
3.  A. Lashkari, M. Alikhani, Measurement and calculation of power and temperature coefficients of TRR using isothermal method in natural circulation, Iranian Physic Conference, Yazd university, 2016 (in Persian)
 
4.  A. Lashkari,‌ Reactivity power and temperature Coefficients Determination of the TRR,‌ 24 International Conference Nuclear Energy for New Europe, Portoroz Slovenia, NENE, 2015
 
5.  AEOI,‌ Safety Analysis Report for the Tehran Research Reactor,‌ Tehran-Iran, (2018).
 
6.   AEOI,‌ Nuclear Reactor and Safety School, TRR experiments Guide
 
 
7.    A. Lashkari et al,‌ Effective delayed neutron fraction and prompt  neutron lifetime of Tehran research reactor mixed-core,‌ Annals of nuclear energy 55 ,265-271, (2013).
 
8.  Pablo Abbate ,INVAP, CONVEX V 3.40,.,‌ A program for thermal-hydraulic analysis of a MTR-type core in natural circulation regime. (2002)
 
9.   Yari, Maedeh, et al,‌ Three dimensional analysis of temperature effect on control rod worth in TRR. Nuclear Engineering and Technology 50.8 1266-1276. (2018):
 
‌10.  T‌. M‌A‌K‌M‌A  et al. Validation of the Stable Period Method Against Analytic Solution – IGORR conference, 2017

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