scholarly journals RESULTS OF VERA APPLICATION TO THE AP1000® PWR STARTUP

2021 ◽  
Vol 247 ◽  
pp. 20003
Author(s):  
F. Franceschini ◽  
D. Salazar ◽  
A. Godfrey

This paper describes the application of the Virtual Environment for Reactor Applications, VERA, under development by the Consortium for Advanced Simulation of LWRs (CASL) to the core physics analysis of the AP1000 PWR. The AP1000 PWR features an advanced first core with radial and axial heterogeneities which provides significant enhancements compared to traditional first cores, allowing best fuel usage and short transition to the equilibrium cycle with subsequent fuel reloads. These core advanced features can pose some challenges to the core physics tools making application of VERA to the AP1000 PWR first core especially relevant to qualify VERA performance. This paper focuses on the qualification efforts at hot zero power conditions, where Monte-Carlo reference solutions have also been established. In particular, the paper focuses on the comparison of the predictions obtained with VERA for the four AP1000 units that recently started up with the measured values. It is shown that there is excellent agreement between VERA and the key reactor physics parameters measured during the AP1000 startup.

Author(s):  
Ze-guang Li ◽  
Kan Wang ◽  
Gang-lin Yu

In the reactor design and analysis, there is often a need to calculate the effects caused by perturbations of temperature, components and even structure of reactors on reactivity. And in sensitivity studies, uncertainty analysis of target quantities and unclear data adjustment, perturbation calculations are also widely used. To meet the need of different types of reactors (complex, multidimensional systems), Monte Carlo perturbation methods have been developed. In this paper, several kinds of perturbation methods are investigated. Specially, differential operator sampling method and correlated tracking method are discussed in details. MCNP’s perturbation calculation capability is discussed by calculating certain problems, from which some conclusions are obtained on the capabilities of the differential operator sampling method used in the perturbation calculation model of MCNP. Also, a code using correlated tracking method has been developed to solve certain problems with cross-section changes, and the results generated by this code agree with the results generated by straightforward Monte Carlo techniques.


1968 ◽  
Vol 46 (10) ◽  
pp. S189-S196 ◽  
Author(s):  
K. O. Thielheim ◽  
E. K. Schlegel ◽  
R. Beiersdorf

Three-dimensional Monte Carlo calculations have been performed on the trajectories of high-energy hadrons in extensive air showers. The central electron density and gradient of distribution are obtained for individual electromagnetic cascades together with coordinates at the level of observation. Various assumptions concerning primary mass number and energy, distributions of strong interaction parameters, and fragmentation mechanisms are discussed with respect to the production of steep maxima of electron density by single electromagnetic cascades in the core region of extensive air showers.


Author(s):  
F. W. Liou

Abstract Due to the current advances in simulation, computer graphics, robotics, and other related technologies, virtual environment has become a future trend in design and development of new products. This paper summarizes the current enabling technologies to develop a virtual environment for parts handling applications, such as parts feeding, assembling, and robotic grasping. A special focus is on developing a physically-based simulation system, which is the core of a virtual parts handling environment. Critical technologies such as object collision detection and response, contact modeling and friction modeling are reviewed. The technological challenges in these areas are also pointed out.


2018 ◽  
Vol 170 ◽  
pp. 01008
Author(s):  
Davide Mancusi ◽  
Alice Bonin ◽  
François-Xavier Hugot ◽  
Fadhel Malouch

TRIPOLI-4® is a Monte-Carlo particle-transport code developed at CEA-Saclay (France) that is employed in the domains of nuclear-reactor physics, criticality-safety, shielding/radiation protection and nuclear instrumentation. The goal of this paper is to report on current developments, validation and verification made in TRIPOLI-4 in the electron/positron/photon sector. The new capabilities and improvements concern refinements to the electron transport algorithm, the introduction of a charge-deposition score, the new thick-target bremsstrahlung option, the upgrade of the bremsstrahlung model and the improvement of electron angular straggling at low energy. The importance of each of the developments above is illustrated by comparisons with calculations performed with other codes and with experimental data.


2020 ◽  
Vol 225 ◽  
pp. 03007
Author(s):  
Tanja Goričanec ◽  
Domen Kotnik ◽  
Žiga Štancar ◽  
Luka Snoj ◽  
Marjan Kromar

An approach for calculating ex-core detector response using Monte Carlo code MCNP was developed. As a first step towards ex-core detector response prediction a detailed MCNP model of the reactor core was made. A script called McCord was developed as a link between deterministic program package CORD-2 and Monte Carlo code MCNP. It automatically generates an MCNP input from the CORD-2 data. A detailed MCNP core model was used to calculate 3D power distributions inside the core. Calculated power distributions were verified by comparison to the CORD-2 calculations, which is currently used for core design calculation verification of the Krško nuclea power plant. For the hot zero power configuration, the deviations are within 3 % for majority of fuel assemblies and slightly higher for fuel assemblies located at the core periphery. The computational model was further verified by comparing the calculated control rod worth to the CORD-2 results. The deviations were within 50 pcm and considered acceptable. The research will in future be supplemented with the in-core and ex-core detector signal calculations and neutron transport outside the reactor core.


1988 ◽  
Vol 108 ◽  
pp. 426-427
Author(s):  
Hideyuki Suzuki ◽  
Katsuhiko Sato

SN1987A gave us the first opportunity to study the supernova core directly by providing us the neutrino signal from the core. The observational data of the neutrino flux detected by Kamiokande[1] and IMB[2] show surprisingly good agreements with the theoretical predictions as a whole[3,4]. The fundamental concept of the collapse driven supernova explosion is confirmed for the first time. On the other hand, there are some puzzles. The most peculiar feature of the data is the 7 seconds gap of the Kamiokande data. The first 8 events of Kamiokande were detected in 2 seconds, following the 7 seconds gap and the last 3 events in 4 seconds. Of course just only 7 seconds gap is not unnatural if small neutrino flux come. But there were detected 3 events after the gap. These 3 events may not be produced by the weak flux. We can estimate the time integrated luminosity of corresponding to the last 3 events and get the large value such as 7 · 1052erg [5]. Can we get out of this inconsistency, 3 events after the 7 seconds gap? If not, we may need to consider some nonstandard mechanism of the neutrino emission at the late time. In order to investigate the probability of the case in which there is a 7 seconds gap before 3 events, we have performed Monte Carlo simulations for the simple model of neutrino flux.


2018 ◽  
Vol 14 (S342) ◽  
pp. 184-188
Author(s):  
J. C. Rodríguez-Ramírez ◽  
Elisabete M. de Gouveia Dal Pino ◽  
R. Alves Batista

AbstractVery high energy (VHE) emission has been detected from the radio galaxy NGC1275, establishing it as a potential cosmic-ray (CR) accelerator and a high energy neutrino source. We here study neutrino and γ-ray emission from the core of NGC1275 simulating the interactions of CRs assumed to be accelerated by magnetic reconnection, with the accreting plasma environment. To do this, we combine (i) numerical general relativistic (GR) magneto-hydrodynamics (MHD), (ii) Monte Carlo GR leptonic radiative transfer and, (iii) Monte Carlo interaction of CRs. A leptonic emission model that reproduces the SED in the [103-1010.5] eV energy range is used as the background target for photo-pion interactions+electromagnetic cascading. CRs injected with the power-law index κ=1.3 produce an emission profile that matches the VHE tail of NGC1275. The associated neutrino flux, below the IceCube limits, peaks at ∼PeV energies. However, coming from a single source, this neutrino flux may be an over-estimation.


2015 ◽  
Vol 82 ◽  
pp. 85-89 ◽  
Author(s):  
Yasunobu Nagaya ◽  
Keisuke Okumura ◽  
Takamasa Mori

Author(s):  
Mancang Li ◽  
Kan Wang ◽  
Dong Yao

The general equivalence theory (GET) and the superhomogenization method (SPH) are widely used for equivalence in the standard two-step reactor physics calculation. GET has behaved well in light water reactor calculation via nodal reactor analysis methods. The SPH was brought up again lately to satisfy the need of accurate pin-by-pin core calculations. However, both of the classical methods have their limitations. The super equivalence method (SPE) is proposed in the paper as an attempt to preserve the surface current, the reaction rates and the reactivity. It enhances the good property of the SPH method through reaction rates based normalization. The concept of pin discontinuity factors are utilized to preserve the surface current, which is the basic idea in the GET technique. However, the pin discontinuity factors are merged into the homogenized cross sections and diffusion coefficients, thus no additional homogenization parameters are needed in the succedent reactor core calculation. The eigenvalue preservation is performed after the reaction rate and surface current have been preserved, resulting in reduced errors of reactivity. The SPE has been implemented into the Monte Carlo method based homogenization code MCMC, as part of RMC Program, under developed in Tsinghua University. The C5G7 benchmark problem have been carried out to test the SPE. The results show that the SPE method not only suits for the equivalence in Monte Carlo based homogenization but also provides improved accuracy compared to the traditional GET or SPH method.


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