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[en] Highlights: • A short description of nuclear fuel behaviour and its modelling in a fuel performance code. • A list of uncertainty sources in fuel behaviour modelling area. • Some examples of uncertainty quantification in modelling. • Some requirements for a generalization of uncertainty quantification in the future. - Abstract: Fuel performance codes describe the physical phenomena occurring in fuel during its irradiation in steady-state and transient conditions. In this paper, the principles of the modelling of nuclear fuel behaviour are presented. Many reasons show that it is also important to consider uncertainties in the fuel modelling process. It can be experimental reasons (validation database and material properties determination), uncertainties in the modelling process itself (lack of knowledge for example). This paper also presents several applications of uncertainty quantification and sensitivity analysis applied to fuel behaviour modelling. The first example is about the validation process of the fuel performance code, which results in a quantification of the uncertainty of the calculated quantities. The second application is about the use of the code in safety analysis to determine probabilities of failure considering epistemic and random uncertainties. In the last application, we show how important it is to quantify modelling uncertainties in the calibration process of complex physical models.
[en] Through the statistical data of the nuclear material that it had been used in the project, the date of Material Unaccounted For (MUF) is calculated, then it is used to calculate the standard deviation (σMUF) and relative standard deviation (δMUF) by the method of MUF evaluation. The one of results showed that the date of MUF is less than the double σMUF, it accounts for that the confidence coefficient of MUF is more than 95%, it conforms with the standard of the national laws and regulations; but another showed the date of δMUF is more than 0.3%, it did not meet the requirements of evaluation standards. The possible reasons were discussed in this article, it is suggested to establish and improve the system retention measurement method, select appropriate measurement method, analysis method and sampling method to improve the nuclear material balance work. (authors)
[en] The analysis and design of the civil structures of nuclear fuel cycle facilities (NFCF) are much more stringent and conservative when compared to the regular industrial structures. In India, the guidelines and stipulation for analysis and design of nuclear power plants (NPP) are enumerated by Atomic Energy Regulatory Board (AERB). However, the nuclear fuel cycle facilities are yet to be included in the gamut of these stipulations. The term 'Nuclear Fuel Cycle Facility' normally indicate buildings for fuel fabrication, spent fuel storage, fuel reprocessing and waste management, other than the NPPs. Hence, the analysis and design of these facilities are presently being conducted with the national (BlS, AERB) and international (ASCE, ACI, IAEA) standards under the tutelage of Bhabha Atomic Research Centre Safety Council. In this paper, the various aspects involved in the analysis and design of nuclear fuel cycle concrete buildings would be discussed
[en] As a supporter and leader in nuclear fuels and materials research and reactor life management, Canadian Nuclear Laboratories (CNL) has taken the opportunity to broaden their capabilities, investing in a shielded dual beam Scanning Electron Microscope + Focused Ion Beam (SEM/FIB) connected to a glove box. The dual beam is presently being installed at the Fuels and Materials hot cell (FMC) facility at Chalk River Labs. Defi systems France created an innovative solution for pairing a modified Zeiss SEV1/FIB CROSS BEAM 550L with a custom designed glove box, and incorporating a custom shielded enclosure with a connection tunnel and manipulator driven sample holder gripper that has been delivered to CNL depicted. The installation of a lead wall and the use of Waelischmiller A200 manipulators will turn this system into a functional expansion to our hot cell capabilities, allowing us to preform operations involving PIE work on reactor components as well as fuel. (author)
[en] Nuclear materials are highly complex multiscale, multiphysics systems and an effective prediction of nuclear reactor performance and safety requires simulation capabilities that exhibit a very tight coupling between different physical phenomena. The Idaho National Laboratory’s Multiphysics Object Oriented Simulation Environment (MOOSE) provides the computational foundation for performing such simulations. The simulation platform currently consists of the continuum scale fuel performance code BISON, the mesoscale phase field code MARMOT, and a new application called YELLOWJACKET is under development to directly couple thermodynamic equilibrium and kinetics in order to model corrosion and fuel problems. As part of YELLOWJACKET, a thermochemistry code is being developed to provide rapid access to thermodynamic databases and perform thermochemical calculations for a range of different materials, which is currently in its infancy. This paper describes preliminary work in YELLOWJACKET development and plans for developing capabilities of practical interest to the nuclear industry. (author)
[en] In any typical process plant where liquids are handled, tanks and pumps are invariably present. Now-a-days, real-time control, interlocking and continuous monitoring are handled by PLC's or DCS systems. Though, they can reliably and safely control continuous processes; they often don't provide full-proof solutions for batch processes requiring human interventions. Fluid Transfer system (or Tank-Pump system) is one of such batch processes
[en] Stirred tank is the most commonly used equipment for homogenous and heterogeneous mixing required for various unit operations and reaction's. Some of the applications in nuclear fuel cycle are leaching of uranium from its ore and precipitation of ammonium diuranate. Processing at higher capacity requires larger tanks and in such tanks a single impeller cannot provide adequate mixing. This necessitates use of stirred tanks having multiple impellers. Understanding the interaction between impellers in such stirred tanks is important to understand its implications on the process performance. This study is an attempt to understand the hydrodynamics of a batch stirred tank having three Rushton turbine impellers by conducting experiments and Computational Fluid Dynamics (CFD) simulations. Mixing time and vortex depth are measured experimentally at different rotational speeds and gas flow rates. To have detailed insights into the hydrodynamics, a CFD model of the stirred tank is developed and validated with experimental data of vortex depth
[en] Since the 1970s, aircraft crash accidents have been considered as one of the severest external events that should be evaluated for license application of nuclear reactors. After the 9.11 terrorist attacks, many countries have performed safety assessment against intentional or targeted aircraft crashes into nuclear related facilities. In some countries, assessment against targeted aircraft crash was enforced by regulation and considered an important task for license approval. Safety assessment against aircraft crash is a technically difficult task and many countries manage R&D programs to improve its reliability. In this paper, regulations of many countries regarding safety assessment against aircraft crash are summarized, separating regulations for accident aircraft crash and those for targeted aircraft crash. Research performed in various countries on safety assessment of nuclear facility against aircraft crash are summarized, with a focus on spent nuclear fuel dry storage facilities
[en] USNC (Ultra Safe Nuclear) is a private US (owned and controlled) company spin-off from the DOE Labs, working to commercialize our fuel and reactor technologies. USNC develops and promotes its technology in three areas: Fully Ceramic Micro-encapsulated (FCM) fuel-origins US DOE Programs; Micro Modular Reactor (MMR)-Small Modular Gas-Cooled FCM Reactor; Advanced Systems: Space Nuclear Power, Advanced Terrestrial Reactors. The Micro Modular Reactor Program: USNC, with primary partner Ontario Power and Gas, leads the race to provide energy as a service for remote mines and communities in Northern Canada; Currently USNC is in Stage 3 negotiations for MMR Demo Reactor, Chalk River Site.