Experimental Investigation On the Retention of Soluble Particles by Pool Scrubbing

Author(s):  
René Vennemann ◽  
Michael Klauck ◽  
Hans-Josef Allelein

Abstract In the late stage of a severe loss-of-coolant accident, the pressure in the containment building of a nuclear power plant could rise beyond the design limits and thus endanger its structural integrity. Therefore, to avoid pressure failure, it may be necessary to perform con-trolled venting of the containment. During the event of an accident, a large amount of fission and activation products are released into the containment as airborne particles (aerosols). These particles are filtered during the venting process, usually with the help of wet filters, in order to keep risks to the surrounding environment to a minimum. Consequently, the knowledge of the retention processes in a water reservoir (pool scrubbing) is of central im-portance for such filtered containment venting systems (FCVS) and for reactor concepts in which water reservoirs are used for pressure reduction (e.g. condensation chamber of a BWR). Investigations on pool scrubbing are carried out in the SAAB test facility at the Juelich Research Centre. SAAB is a unique large scale facility with the ability to perform a great var-iation of experiments using various measurement tools. The influence of numerous parameters, such as the height of the water pool, solubility of aerosols and concentration on the retention capacity, is investigated by means of separate effect studies on both insoluble and soluble particles. This paper gives a detailed overview over the facility and includes example results of the first test series with soluble particles including cesium iodine (CsI).

Author(s):  
Anna Dahl ◽  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Willy Vincent

Abstract The 4-years European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) has been launched in June 2017. One of its objectives is to study the transferability of material ductile properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment. The study of properties transferability is based on a wide experimental programme which includes a full set of fracture experiments conducted on conventional fracture specimens and large scale components (mainly pipes). Three materials are considered in the programme : a ferritic steel WB36 typical from secondary feed water line in German PWR reactors, an aged stainless steel austenitic weld representative of EPR design and a typical VVER austenitic dissimilar weld (DMW). This paper describes the experimental work conducted on the ferritic steel WB 36 (15NiCuMoNb5) and summarizes the experimental results available after 2 years of work. Numerous mechanical tests have been conducted on a wide panel of fracture mechanics specimens for a full characterization of the ferritic steel: Tensile properties, Hardness, Charpy Energy, pre-cracked Charpy PCC, Master curve on CT and SENT specimens, ductile tearing properties on CT and SENT specimens. In parallel, it is planned to test three 4PB large scale tests on pipings (FP1, FP2 and FP3) at room temperature on the EDF test facility with 3 configurations (shape, size and location) of cracks: through wall crack (TWC), internal and external ½ elliptical cracks. Progress of these large scale experiments is described including first results.


2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Yeong-il Kim ◽  
Yong Bum Lee ◽  
Chan Bock Lee ◽  
Jinwook Chang ◽  
Chiwoong Choi

Korea imports about 97% of its energy resources due to a lack of available energy resources. In this status, the role of nuclear power in electricity generation is expected to become more important in future years. In particular, a fast reactor system is one of the most promising reactor types for electricity generation, because it can utilize efficiently uranium resources and reduce radioactive waste. Acknowledging the importance of a fast reactor in a future energy policy, the long-term advanced SFR development plan was authorized by KAEC in 2008 and updated in 2011 which will be carried out toward the construction of an advanced SFR prototype plant by 2028. Based upon the experiences gained during the development of the conceptual designs for KALIMER, KAERI recently developed advanced sodium-cooled fast reactor (SFR) design concepts of TRU burner that can better meet the generation IV technology goals. The current status of nuclear power and SFR design technology development program in Korea will be discussed. The developments of design concepts including core, fuel, fluid system, mechanical structure, and safety evaluation have been performed. In addition, the advanced SFR technologies necessary for its commercialization and the basic key technologies have been developed including a large-scale sodium thermal-hydraulic test facility, super-critical Brayton cycle system, under-sodium viewing techniques, metal fuel development, and developments of codes, and validations are described as R&D activities.


Author(s):  
Mingtao Cui ◽  
Tao Zhang

ACME facility (Advanced Core-cooling Mechanism Experiment) is a large-scale test facility used to validate the performance of passive core-cooling system under SBLOCA (Small Break Lost of Coolant Accident) for the CAP1400, an upgraded passive safety nuclear power plant of AP1000. To simulate the features of passive safety system properly, DELTABAR, a kind of differential pressure flow meter, is designed to measure different mass flow of ACME. Because of the low pressure loss of DELTABAR, Zero-Drift problem of differential pressure flow meters in ACME is amplified, and some of the measured values are distorted seriously. To minimize the influence of Zero-Drift, analysis on zero-drift phenomenon is made, and a compensation method is proposed. The method is applying to PBL flow meters, and the result shows that the method is applicable.


Author(s):  
Alain Flores y Flores ◽  
Guido Mazzini

Abstract In order to develop an appropriate knowledge to support the SUJB (State Office of Nuclear Safety), the CVR (Research Centre Rež), in collaboration with SURO (National Radiation Protection Institute) is developing a methodology to simulate nuclear power plants under accidental conditions. A particular effort is focused in the severe accident phenomenology where hydrogen deflagration carries a critical issue for the containment integrity, such as Fukushima Daiichi accident. For this purpose, THAI (Thermal-hydraulics, hydrogen, aerosol and iodine) experimental campaigns are chosen due to the several tests involved in different conditions. THAI containment test facility is used to open questions concerning the behaviour of hydrogen, iodine and aerosols in the containment of water-cooled reactors during severe accidents. The Fukushima Daiichi Accident demonstrates that the hydrogen deflagration could lead to a significant containment damage. For this reason, a particular attention is given to the hydrogen deflagration scenario. All simulations are prepared and modelled in MELCOR 2.1. The results obtained showed a strong influence related with some factors as: the nodalization pattern, control volume number (CV), flow paths number FP and time step. In order to assess the THAI model with the THAI final reports, a sensitivity analysis focused with those parameters was performed.


Author(s):  
Tomas Nicak ◽  
Herbert Schendzielorz ◽  
Elisabeth Keim ◽  
Gottfried Meier ◽  
Dominique Moinereau ◽  
...  

The safety and reliability of all systems has to be maintained throughout the lifetime of a nuclear power plant. Continuous R&D work is needed in targeted areas to meet the challenges of long term operation of existing and new plants designs. The European project STYLE aims to develop and validate advanced methods of structural integrity assessment applicable in the ageing and lifetime management of primary circuit components. There are three large scale mock-up tests in STYLE each of them dedicated to investigate specific effects. This paper presents the work related to Mock-up3, which is dedicated to investigate influence of cladding on the crack initiation and propagation as well as the transferability of material properties from small scale specimens to a large scale component. The performed post-test analyses focus on both the further understanding and interpretation of the Mock-up3 test and on the effect of cladding on structural integrity and LBB behavior of reactor coolant pressure boundary components.


2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Ki-Yong Choi ◽  
Yeon-Sik Kim ◽  
Chul-Hwa Song ◽  
Won-Pil Baek

A large-scale thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), has been operated by KAERI. The reference plant of ATLAS is the APR1400 (Advanced Power Reactor, 1400 MWe). Since 2007, an extensive series of experimental works were successfully carried out, including large break loss of coolant accident tests, small break loss of coolant accident tests at various break locations, steam generator tube rupture tests, feed line break tests, and steam line break tests. These tests contributed toward an understanding of the unique thermal-hydraulic behavior, resolving the safety-related concerns and providing validation data for evaluation of the safety analysis codes and methodology for the advanced pressurized water reactor, APR1400. Major discoveries and lessons found in the past integral effect tests are summarized in this paper. As the demand for integral effect tests is on the rise due to the active national nuclear R&D program in Korea, the future prospects of the application of the ATLAS facility are also discussed.


Author(s):  
Andrea Querol ◽  
Sergio Gallardo ◽  
Gumersindo Verdú

Several experimental facilities, such as the Large Scale Test Facility (LSTF) of the Japan Atomic Energy Agency (JAEA), have been built to reproduce some accidental scenarios because full-scale testing is usually impossible to perform. One of the objectives of these Integral Test Facilities (ITFs) is to obtain measured data to be compared to simulations in order to test the capability of the thermalhydraulic codes to reproduce experimental conditions. The applicability of these experimental results to a full-size power plant system depends on the scaling criteria adopted. The present paper is focused on the simulation and the scaling of the Test 1-2 in the frame of the OECD/NEA ROSA Project to a Nuclear Power Plant (NPP). This test simulates a hot leg 1% Small Break Loss-Of-Coolant Accident (SBLOCA) in a Pressurized Water Reactor (PWR) under the actuation of High Pressure Injection (HPI) system and Accumulator Injection System (AIS). A scaled-up NPP TRACE5 input has been developed from a LSTF TRACE5 model validated by authors in previous works. The scaled-up model has been developed conserving the power-to-volume scaling ratios of LSTF components, initial and boundary conditions. Lengths and diameters of hot legs have been scaled from LSTF model trying to conserve Froude number. A comparison between both TRACE5 models (LSTF and scaled-up NPP) is performed (system pressures, discharged inventory and collapsed liquid levels). Special TRACE5 models such as Choked flow model and OFFTAKE model have been tested. A 3D VESSEL component has been tested in comparison to 1D TEE component to simulate the hot leg where the SBLOCA is located and varying the break orientation (downwards and upwards). Finally, a sensitivity analysis has been made to determine the effect of the break size in the SBLOCA range.


Author(s):  
Tomas Nicak ◽  
Elisabeth Keim

The purpose of this paper is to introduce a new EUROATOM project focusing on the structural integrity assessment of reactor coolant pressure boundary components (RCPB) relevant to ageing and life time management. The project started in January 2010 and will last 4 years. The project is coordinated by AREVA NP GmbH with 20 partner organizations from Europe, one collaborator from USA and one collaborator from Russia: AEKI, Hungary; AREVA NP GmbH, Germany (coordination, WP2 leader); AREVA NP SAS, France; Bay Zoltan, Hungary; British Energy Generation Ltd., UK (WP7 leader); CEA, France (WP1 leader); EDF, France; IdS, France; INR, Romania; IWM, Germany; JRC, Netherlands (WP4 leader); NRI, Czech Republik; NRG, Netherlands; SCK-CEN, Belgium; Serco Assurance Technical Services, UK (WP3 and WP5 leader); University of Bristol, UK; University of Manchester, UK; Technatom, Spain; Vattenfall, Sweden (WP6 leader); VTT, Finland. Within STYLE (Structural integrity for lifetime management – non-RPV components) realistic failure models for some of the key components will be identified. The range of assessment tools considered will include those for assessment of component failure by advanced fracture mechanics analyses validated on small and large scale experiments, quantification of weld residual stresses by numerical analysis and by measurements, stress corrosion crack initiation/ growth effects and assessment of RCPB components (excluding the reactor pressure vessel) under dynamic and seismic loading. Based on theoretical and experimental results, performance assessment and further development of simplified engineering assessment methods (EAM) will be carried out considering both deterministic and probabilistic approaches. Integrity assessment case studies and large scale demonstration experiments will be performed on Mock-ups of safety-relevant components. These will include a repair weld in an aged butt-welded austenitic pipe, a dissimilar narrow gap TIG weld (following the EPR design) and a cladded ferritic pipe. Moreover experiments on specimens and feature test pieces will be carried out to support the large scale Mock-up analyses. The end product of the project (“STYLE TOOLS”) will comprise best practice guidelines on the use of advanced tools, on improvement and qualification of EAM as a part of European Leak-before-break (LBB) procedures and on life time management of the integrity of RCPB components in European nuclear power plants. The project will interact with the European Network of Excellence NULIFE.


Author(s):  
Mian Xing ◽  
Xiao Hu ◽  
Yaodong Chen ◽  
Liangxing Li ◽  
Weimin Ma

OECD/NEA ROSA/LSTF project tests are performed on the Large Scale Test Facility (LSTF). LSTF is a full-height, full-pressure and 1/48 volumetrically-scaled two-loop system which aims to simulate Japanese Tsuruga-2 Westinghouse-type 4-loop PWR. ROSA-V Test 6-1 simulates a pressure vessel (PV) upper-head small break loss-of-coolant accident (SBLOCA) with a break size equivalent to 1.9% of the volumetrically scaled cross-sectional area of the reference PWR cold leg. By building a TRACE calculation model of LSTF and PV upper-head, the paper dedicated to assess the effect of different modeling options and parameters on simulating thermal hydraulic behaviors of TRACE code. The results show that TRACE code well reproduce the physical phenomena involved in this type of SBLOCA scenarios. Almost all the events in the experiment are well predicted by the model based on TRACE code. In addition, the sensitivity of different models and parameters are investigated. For example, the code slightly overestimated the break mass flow from upper head which could affect the accuracy of the results significantly. The rising of core exit temperature (CET) is significantly influenced by the bypass flow area between downcomer and hot leg.


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