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CALCULATION AND EXPERIMENTAL INVESTIGATION OF VOID EFFECT IN RESEARCH REACTORS

Iqbal, Masood (1999) CALCULATION AND EXPERIMENTAL INVESTIGATION OF VOID EFFECT IN RESEARCH REACTORS. PhD thesis, Quaid-i-Azam University, Islamabad.

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Abstract

The core-wide* void coefficient of reactivity has been determined both theoretically and experimentally for a typical pool type research reactor. For this purpose, the Pakistan Research Reactor-1(PARR-1) has been employed. Three-dimensional experimental measurements were carried out throughout PARR-1 core using teflon and aluminum stringers simulating voids in both radial and axial directions especially in the central flux trap region. The dependence of the void coefficient on the void volume has also been studied and result show a saturting behavior with the positive induced reactivity reaching a maximum value of 0.35% k/k for 450 cm3 void volume in the central flux trap region. For theoretical predictions, the neutron transport theory based WIMS-D/4 and diffusion theory based CITATION codes have been used. Both theoretical predictions and experimental measurements yield a positive value of the void coefficient in the central flux trap region whereas the overall measured void coefficient for the system remains negative. The quadratic behavior of various diffusion parameters in the water reflector region outside the core, measured in a separate source driven facility, is in good agreement with previous such measurements. Detailed parametric measurements have also been made including the control rod worth, the element-wise axial neutron flux profiles, the neutron flux spectra and the temperature coefficient of reactivity. The dynamic response of the PARR-1 has also been studied using the measured values of void coefficients of reactivity along with other experimental data employing the modified version of PARET computer code. For the postulated step and ramp insertion of reactivity and slow & fast loss of flow transients, theoretical calculations predict safe margin below the onset of nucleate boiling regime. *Core-wide stands for accessible positions for experiment

Item Type:Thesis (PhD)
Uncontrolled Keywords:reactor parameter, neutron energy spectra, void coefficient, flux trap, research reactors
Subjects:Engineering & Technology (e) > Engineering(e1)
ID Code:454
Deposited By:Mr. Muhammad Asif
Deposited On:03 Aug 2006
Last Modified:04 Oct 2007 21:01

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