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Rakesh Chawla

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Publications associées (141)

Refined Monte Carlo analysis of the H.B. Robinson-2 reactor pressure vessel dosimetry benchmark

Rakesh Chawla, Hakim Ferroukhi, Alexander Vasiliev

Refined analysis, based on use of the Monte Carlo code MCNPX-2.4.0, is presented for the "H.B. Robinson-2 pressure vessel dosimetry benchmark", which is a part of the Radiation Shielding and Dosimetry Experiments Database (SINBAD). First, the performance o ...

Elsevier2011

TRACE qualification via analysis of the EIR gas-loop experiments with smooth rods

Rakesh Chawla, Aaron Simon Epiney, Konstantin Mikityuk

Several gas-loop experimental programs were carried out during the 1970-1980s at the Eidgenossisches Institut fur Reaktorforschung (EIR, now PSI), Switzerland. In the present work, a wide range of thermalhydraulics tests for smooth rods, which form part of ...

Elsevier2010

Freshly induced short-lived gamma-ray activity as a measure of fission rates in lightly re-irradiated spent fuel

Rakesh Chawla, Hanna Kröhnert

A new measurement technique has been developed to determine fission rates in burnt fuel following re-irradiation in a zero-power research reactor The development has been made in the frame of the LIFE@PROTEUS program at the Paul Scherrer Institute which ai ...

2010

Experimental validation of radial reconstructed pin-power distributions in full-scale BWR fuel assemblies with and without control blade

Rakesh Chawla, Flavio Dante Giust

Total fission rate measurements have been performed on full-size BWR fuel assemblies of type SVEA-96+ in the zero power reactor PROTEUS at the Paul Scherrer Institute. This paper presents comparisons of reconstructed 2D pin fission rates from nodal diffusi ...

Elsevier2010

FAST code system: Review of recent developments and near-future plans

Rakesh Chawla, Petr Petkevich, Aurélia Chenu, Konstantin Mikityuk, Jiri Krepel

The FAST code system is currently being developed and used at the Paul Scherrer Institut for static and transient analysis of the main Generation 4 fast-spectrum reactor concepts: sodium-, helium-, and gas-cooled fast reactors. The code system includes the ...

American Society of Mechanical Engineers2010

Determination of within-rod caesium and europium isotopic distributions in high burnup fuel rods through computerised gamma-ray emission tomography

Rakesh Chawla, Fabian Jatuff, Stefano Caruso

Computerised gamma-ray emission tomography has been applied to single PWR UO2 fuel rods, with pellet averaged burnups of 52, 71, 91 and 126 GWd/t respectively, for the determination of 134Cs, 137Cs and 154Eu internal radial distributions. State-of-the-art ...

Elsevier Science B.V.2009

Validation of Monte Carlo predictions of LWR-PROTEUS safety parameters using an improved whole-reactor model

Michaël Plaschy, Rakesh Chawla, Fabian Jatuff

The recent experimental programme conducted in the PROTEUS research reactor at the Paul Scherrer Institute (PSI) has concerned detailed investigations of advanced light water reactor (LWR) fuels. More than fifteen different configurations of the multi-zone ...

Elsevier Science Ltd.2009

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Rakesh Chawla

Elsevier Ltd2009

Single-phase mixing studies by means of a directly coupled CFD/system-code tool

Rakesh Chawla, Davide Bertolotto, Horst-Michael Prasser

The present paper describes the coupling of the 3D computational fluid dynamics (CFD) code CFX with the best estimate thermal-hydraulic code TRACE. Two different coupling schemes - one explicit and the other semi-implicit - have been tested. Verification o ...

Elsevier Science Ltd.2009

Development and benchmarking of a mechanical model for GFR plate-type fuel

Rakesh Chawla, Petr Petkevich, Konstantin Mikityuk

The reference fuel design currently being considered within the Generation-IV Gas-cooled Fast Reactor (GFR) project is a ceramic plate matrix with a honeycomb inner structure containing small fuel cylinders. The fuel is mixed plutonium-uranium carbide, whi ...

Elsevier Science Ltd.2009

Void reactivity coefficient benchmark results for a 10x10 BWR assembly in the full 0-100% void fraction range

Rakesh Chawla, Fabian Jatuff, Flavio Dante Giust

A boiling water reactor SVEA-96+ fresh fuel lattice has been used as the basis for a benchmark study of the void reactivity coefficient at assembly level in the full voidage range. Results have been obtained using the deterministic codes CASMO-4, HELIOS, P ...

Elsevier Science Ltd.2009

Experimental validation of reaction rate distributions for a SVEA-96+ BWR assembly with hafnium control blades

Michaël Plaschy, Rakesh Chawla, Fabian Jatuff, Flavio Dante Giust

The accurate estimation of reactor physics parameters related to the presence of cruciform absorber blades in boiling water reactors (BWRs) is important for safety assessment and for achieving flexible operation during the cycle. Characteristics that are a ...

Atomic Energy Society of Japan2009

Cross-section modelling effects on pressurised water reactor main steam line break analyses

Rakesh Chawla, Hakim Ferroukhi, Omar Zerkak

Because of the strong asymmetric overcooling effects occurring during a PWR main steam line break (MSLB) event, an accurate analysis of this transient requires the use of 3-D kinetics methods. An assessment has been made of the relative performance of the ...

Elsevier Science Ltd.2009

Impact of new gadolinium cross sections on reaction rate distributions in 10x10 BWR assemblies

Rakesh Chawla, Fabian Jatuff

Radial distributions of the total fission rate and the238U- capture-to-total-fission (C 8/F tot) ratio were measured in SVEA-96+ and SVEA-96 Optimal assemblies during the LWR-PROTEUS program. Fission rates predicted using MCNPX with JEFF-3.1 cross sections ...

American Nuclear Society2009

Estimation of the fast neutron fluence at control rod tips using a 3-D diffusion/2-D transport multi-step calculation scheme

Rakesh Chawla, Hakim Ferroukhi

This paper presents the development and application of a methodology to estimate, using conventional deterministic lattice/core analysis methods, the fast neutron fluence at the tips of control rods inserted during operation in PWR reactors. The developed ...

Elsevier Ltd2009

TRACE simulation of sodium boiling in pin bundle experiments under loss-of-flow conditions

Rakesh Chawla, Aurélia Chenu, Konstantin Mikityuk

In the framework of PSI's FAST code system, the thermal-hydraulic code TRACE is being extended for representation of sodium two-phase flow. As the currently available version (v.5) is limited to the simulation of only single-phase sodium flow, its applicab ...

Elsevier Science B.V.2009

Diagnostic analysis of pin-removal reactivity worth experiments in a SVEA-96+ test lattice

Rakesh Chawla, Fabian Jatuff, Filippo Tani

The present paper concerns a novel type of integral database generated in the course of the LWR-PROTEUS Phase I experiments, viz. the relative reactivity effects of removing individual fuel pins from a highly heterogeneous BWR assembly. The measurements re ...

Elsevier Science Ltd.2008

Development and characterization of the control assembly system for the large 2400 MWth Generation IV gas-cooled fast reactor

Rakesh Chawla, Gaëtan Girardin, Gérald Rimpault, Konstantin Mikityuk

The present paper is related to the design and neutronic characterization of the principal control assembly system for the reference large (2400 MWth) Generation IV gas-cooled fast reactor (GFR), which makes use of ceramic-ceramic (CERCER) plate-type fuel- ...

Elsevier Science Ltd.2008

Comparison of 3D reaction rate distributions measured in an optima2 BWR assembly with MCNPX predictions

Michaël Plaschy, Rakesh Chawla, Fabian Jatuff

As part of a joint research programme between the Paul Scherrer Institute (PSI) and swissnuclear, with the co-operation of the Leibstadt nuclear power plant in Switzerland and fuel suppliers Westinghouse Sweden, measurements and calculations have been made ...

Elsevier Science Ltd.2008

Comparison of optimised germanium gamma spectrometry and multicollector inductively coupled plasma mass spectrometry for the determination of 134Cs, 137Cs and 154Eu single ratios in highly burnt UO2

Rakesh Chawla, Fabian Jatuff, Stefano Caruso

Non-destructive and destructive methods have been compared to validate their corresponding assessed accuracies in the measurement of 134Cs/137Cs and 154Eu/137Cs isotopic concentration ratios in four spent UO2 fuel samples with very high (52 and 71 GWd/t) a ...

Elsevier Science B.V.2008

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