I= CALCULATION AND EXPERIMENTAL INVESTIGATION OF VOID EFFECT IN RESEARCH REACTORS.
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Title of Thesis
CALCULATION AND EXPERIMENTAL INVESTIGATION OF VOID EFFECT IN RESEARCH REACTORS.

Author(s)
MASOOD IQBAL.
Institute/University/Department Details
Qauid-i-Azam University, Pakistan Institute of Engineering & Applied Sciences
Session
1999
Subject
Applied Sciences
Number of Pages
160
Keywords (Extracted from title, table of contents and abstract of thesis)
reactor parameter, neutron energy spectra, void coefficient, flux trap, research reactors

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.

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2045.07 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents/ Abstract
132.26 KB
2 1 Introduction 1
94.78 KB
  1.1 Review Of Previous Work 3
  1.2 This Work 7
  1.3 Layout Of Thesis 8
3 2 Viod Coefficient In Research Reactors 10
439.29 KB
  2.1 Reactivity Measurement Techniques 11
  2.2 Reactor Description 13
  2.3 Void Coefficient Measurements In A Typical
  2.4 Theoretical Modeling And Simulation 28
  2.5 Effect Of Voids On Neutron Energy Spectra 35
  2.6 Summary 51
4 3 Reactor Parameter Measurements 52
562.64 KB
  3.1 Reactivity Measurements 53
  3.2 Contro Rod Drop Time 54
  3.3 Neutron Flux Measurements 54
  3.4 Diffusion Parameters Measurements 55
  3.7 Data Analysis 71
  3.8 Summary 84
5 4 Transient Analysis Of Parr-1 Using Measured Safety Parameters 87
187.58 KB
  4.1 Modeling And Simulations 87
  4.2 Reactivity Insertion Transients 88
  4.3 Loss- Of-Flow Transients 97
  4.4 Natural Convection Cooling 101
  4.5 Summary 103
6 5 Discussion And Conclusions 105
165.21 KB
  5.1 Voids In Critical Research Reactors 106
  5.2 Reactor Parameter Measurements 108
  5.3 Transient Analysis Using Experimental Data 110
  5.4 Recommendations For Future Work 112
  5.5 References 113
7 6 Appendix 116
663.11 KB
  9 Vita 160