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Rakesh Chawla

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Publications associées (141)

On the effects of oxygen cross-sections in the fast neutron fluence analysis for a reactor pressure vessel scraping test

Rakesh Chawla, Hakim Ferroukhi, Alexander Vasiliev

Studies in support of the assessment of aging structural materials in pressurized water reactors are being performed at the Paul Scherrer Institut. To that aim, a state-of-the-art methodology based on applying a CASMO-4/SIMULATE-3/MCNPX calculation scheme ...

Elsevier Science Ltd.2008

Interpretation of high-burnup fuel annealing tests

Rakesh Chawla, Paul Blair

The growth of the porosity in high-burnup fuel is of particular interest when considering the effect of fission gas retention within the high-burnup structure (HBS). A mechanistic model of porosity growth under annealing conditions for light water reactor ...

Atomic Energy Society of Japan2008

On the performance of ENDF/B-VII.0 data for fast neutron fluence calculations

Rakesh Chawla, Hakim Ferroukhi, Alexander Vasiliev

The newest release of the Evaluated Nuclear Data File, ENDF/B-VII.0, has recently become available, along with the announcement of its significant advances over previous versions. The older ENDF/B releases, however, have been assessed for numerous applicat ...

Elsevier Science Ltd.2008

Management of actinide waste inventories in nuclear phase-out scenarios

Rakesh Chawla, Marco Cometto

The improvement of the "radiological cleanliness" of nuclear energy is a primary goal in the development of advanced reactors and fuel cycles. The multiple recycling of actinides in advanced nuclear systems with fast neutron spectra represents a key option ...

Elsevier Ltd2008

Nondestructive determination of fresh and spent nuclear fuel rod density distributions through computerised gamma-ray transmission tomography

Rakesh Chawla, Fabian Jatuff, Stefano Caruso

The morphology of single PWR UO2 fuel rods has been investigated by employing computerised gamma-ray transmission tomography. Four highly burnt fuel rods of different burnups (from 52 GWd/t to 126GWd/t) and a fresh rod have been investigated. This paper de ...

Atomic Energy Society of Japan2008

Characterisation of radial reaction rate distributions across the 92-pin section of a SVEA-96 Optima2 assembly

Michaël Plaschy, Rakesh Chawla, Fabian Jatuff

Characterisation of the SVEA-96 Optima2 boiling water reactor assembly, in terms of the radial distributions of normalised total fission and 238U capture rates, is reported at its central elevation, i.e. at the 92-pin section, where the one-third part-leng ...

Elsevier Science Ltd.2008

Comparative transient analysis of critical and subcritical 80-MW Pb-Bi eutectic-cooled reactor systems

Rakesh Chawla, Konstantin Mikityuk

A consistent analytical comparison has been made of the transient behavior of critical and subcritical fast-spectrum reactor systems, the basic core design assumed in each case being that of the 80-MW(thermal) mixed-oxide-fueled, Pb-Bi-cooled, experimental ...

American Nucl. Soc.2007

Interpretation of in-phase and out-of-phase BWR oscillations using an extended reduced order model and semi-analytical bifurcation analysis

Rakesh Chawla, Abdelhamid Dokhane

An extended reduced order model is presented and applied to analyze global and regional oscillations in BWRs. Stability and semianalytical bifurcation analyses are performed using this model in conjunction with the bifurcation code BIFDD to determine the s ...

Elsevier2007

BWR stability and bifurcation analysis using reduced order models and system codes: Identification of a subcritical Hopf bifurcation using RAMONA

Rakesh Chawla, Abdelhamid Dokhane

The system code RAMONA, as well as a recently developed BWR reduced order model (ROM), are employed for the stability analysis of a specific operational point of the Leibstadt nuclear power plant. This has been done in order to assess the ROM's applicabili ...

2007

Validation of 134Cs, 137Cs and 154Eu single ratios as burnup monitors for ultra-high burnup UO2 fuel

Rakesh Chawla, Fabian Jatuff, Stefano Caruso

A measurement station has been built for the non-destructive investigation of burnt fuel rod segments through high-resolution gamma spectrometry. Four UO2 pressurised water reactor fuel rod segments with different burnup levels between 50 and 100GWd/t and ...

Elsevier2007

Development of a CASMO-4/SIMULATE-3/MCNPX calculation scheme for PWR fast neutron fluence analysis and validation against RPV scraping test data

Rakesh Chawla, Hakim Ferroukhi, Alexander Vasiliev

A methodology is presented for the accurate assessment of the fast neutron fluence at the reactor pressure vessel (RPV) of a pressurised water reactor (PWR). The basis is the transfer of results from deterministic CASMO-4/SIMULATE-3 core-follow calculation ...

Elsevier Science Ltd.2007

Development and benchmarking of a 2D transient thermal model for GFR plate-type fuel

Rakesh Chawla, Petr Petkevich, Konstantin Mikityuk

Several new fuel designs are currently being considered within the generation-IV gas-cooled fast reactor (GFR) project. One of them, which is the GFR reference design, is a ceramic plate matrix with a honeycomb inner structure containing small fuel cylinde ...

Elsevier Science Ltd.2007

Radial and azimuthal 235U fission and 238U capture distributions in BWR UO2 pins: CASMO-4 and MCNP4C versus activation foil measurements

Michaël Plaschy, Rakesh Chawla, Fabian Jatuff

In the context of the LWR-PROTEUS program, radial and azimuthal 235U fission (F5) and 238U capture (C8) rate distributions have been calculated for zero-burnup pins of a Westinghouse SVEA-96 Optima2 boiling water reactor fuel assembly using the stochastic ...

ANS2007

Investigations of238U captures to total fissions in a Westinghouse SVEA-96+ assembly

Rakesh Chawla, Fabian Jatuff

The reaction-rate ratio C8/Ftot, neutron captures in 238U to total fissions, has been measured in 80 out of 96 fuel rods of a Westinghouse SVEA-96+ boiling water reactor fuel assembly. High-resolution gamma spectroscopy was performed on individual fuel rod ...

American Nuclear Society2007

Statistical uncertainty analysis applied to fuel depletion calculations

Rakesh Chawla

In this paper, we present an uncertainty methodology based on a statistical approach, for assessing uncertainties in lattice code predictions of fuel composition changes with burnup due to uncertainties in the fuel geometric configuration, initial enrichme ...

Atomic Energy Society of Japan2007

A statistical methodology for quantification of uncertainty in best estimate code physical models

Rakesh Chawla, Paolo Vinai

A novel uncertainty assessment methodology, based on a statistical non-parametric approach, is presented in this paper. It achieves quantification of code physical model uncertainty by making use of model performance information obtained from studies of ap ...

Elsevier Science Ltd.2007

Absolute depth-dose-rate measurements for an 192Ir HDR brachytherapy source in water using MOSFET detectors

Rakesh Chawla

Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192Ir source. Measured radial dose rate distributions in wate ...

AIP for American Assoc. Phys. Med2006

Optimised non-invasive method to determine 238U-captures-to-total-fissions in reactor fuel

Rakesh Chawla, Fabian Jatuff

High-resolution gamma spectroscopy was performed on individual fuel rods of a fresh, highly heterogeneous Boiling Water Reactor (BWR) fuel assembly, after irradiation at low power in the PROTEUS reactor at PSI, to determine the ratio of neutron captures in ...

Elsevier2006

Study of spectral heterogeneities for the interpretation of calculational trends in predicting pin power distributions in a SVEA-96+ BWR assembly

Rakesh Chawla, Fabian Jatuff, Filippo Tani

Detailed energy spectra have been calculated with the codes CASMO-4 and BOXER for neutron reaction rates in individual regions of a Westinghouse SVEA-96+ BWR fuel assembly immersed in water at room temperature, as investigated in Core 1A of the LWR-PROTEUS ...

Elsevier2006

Advanced foil activation techniques for the measurement of within-pin distributions of the 63Cu(n,)64Cu reaction rate in nuclear fuel

Rakesh Chawla, Fabian Jatuff

Different foil activation techniques have been used for measuring spatial distributions of the 63Cu(n,)64Cu reaction within two pins of a SVEA-96 Optima2 boiling water reactor fuel assembly, at the critical facility PROTEUS. This reaction is of interest be ...

Elsevier2006

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