Using the RELAP5/MOD2 Code Under Low-Pressure/Low-Temperature Loss-of-Coolant-Accident Conditions

1989 ◽  
Vol 85 (3) ◽  
pp. 285-293 ◽  
Author(s):  
Jan-Li Wang ◽  
Jay F. Kunze
Keyword(s):  
Low Temperature ◽  
Low Pressure ◽  
Loss Of Coolant Accident ◽  
Temperature Loss ◽  
Loss Of Coolant ◽  
Accident Conditions

Flashing Hammer Phenomenon in Rapid Liquid-Liquid Contact

2003 ◽  
Author(s):  
Tatsuya Koga ◽  
Tomoji Takamasa ◽  
Tatsuya Hazuku ◽  
Norihiro Fukamachi ◽  
Akira Saito ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Pressure Vessel ◽  
Pressure Oscillation ◽  
Low Pressure ◽  
Steam Generation ◽  
Transient Phenomena ◽  
Saturated Water ◽  
Loss Of Coolant Accident ◽  
Temperature Water

In a wall crack accident or loss-of-coolant accident (LOCA) in an advanced reactor with water filled containment, high pressure saturated water is discharged from the pressure vessel into the low-pressure, low-temperature water of the containment. The discharged saturated water causes flashing and generates steam. Steam is then condensed by the water in the containment. This paper describes our study of high pressure saturated water that rapidly contacts low-pressure, low-temperature water. The purpose of the study was to clarify the transient phenomena that occur when high pressure saturated water blows down from a pressure vessel into a water filled containment during a wall crack accident or LOCA in an advanced reactor. The experimental results revealed that flashing of high-pressure saturated water and a subsequent water hammer occurred under the specified experimental settings. Pressure peaked when steam generation or flashing occurred at the wall surface and the flashing steam condensed. After the peak, pressure oscillated and reached equilibrium condition in a short time. The pressure oscillation might have been caused by a balancing action between the flashing of high pressure saturated water and condensation of the steam generated by flashing in low-pressure, low-temperature water. To check the results of the experiments, numerical analyses were conducted. The numerical results cleared the mechanism behind flashing hammer phenomenon.

Investigation of Air Ingress Into a Vacuum Vessel Related to Particle Re-Suspension and Distribution for Dust Issues in ITER

2017 ◽  
Author(s):  
Emmanuel Porcheron ◽  
Pascal Lemaitre
Keyword(s):  
Large Scale ◽  
Low Pressure ◽  
Normal Operation ◽  
Vacuum Vessel ◽  
Physical Processes ◽  
Time Resolved ◽  
Loss Of Coolant Accident ◽  
Image Velocimetry ◽  
Loss Of Coolant ◽  
Air Ingress

During normal operation of the ITER tokamak, few hundred kilograms of dust containing beryllium (Be) and tungsten (W) will be produced due to the erosion of the walls of the vacuum chamber by the plasma. During a loss of coolant accident (LOCA) or a loss of vacuum accident by air ingress (LOVA), hydrogen could be produced by dust oxidation with steam. Evaluation of the risk of dust and hydrogen explosion, that may lead to a loss of containment, requires studying the physical processes involved in the dust re-suspension and its distribution in the tokamak chamber. This experimental study is conducted by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) to simulate dust re-suspension phenomena induced by high velocity jet under low pressure conditions. Tests are conducted in a large scale facility (TOSQAN, 7 m3) able to reproduce primary vacuum conditions (1 mbar). Optical diagnostics such as PIV technique (Particles Image Velocimetry) are implemented on the facility to provide time resolved measurements of the dust re-suspension in terms of phenomenology and velocity. We present in this paper the TOSQAN facility with its configuration for studying dust re-suspension under low pressure conditions and underway experiments showing the mechanism of dust re-suspension by sonic and supersonic flows.

Analysis of the CSF model for simulated loss of coolant accident conditions

Kerntechnik ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. 111-122 ◽  
Author(s):  
I. Thangamani ◽  
A. Dutta ◽  
V. M. Shanware ◽  
V. Verma ◽  
R. K. Singh
Keyword(s):  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Accident Conditions

scholarly journals EXPERIMENTAL STUDY OF DAMAGED CR-COATED FUEL CLADDING IN POST-ACCIDENT CONDITIONS

2020 ◽  
Vol 28 ◽  
pp. 1-7
Author(s):  
Petr Červenka ◽  
Jakub Krejčí ◽  
Ladislav Cvrček ◽  
Vojtěch Rozkošný ◽  
František Manoch ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Experimental Methodology ◽  
Fuel Cladding ◽  
Loss Of Coolant Accident ◽  
Ring Compression ◽  
Loss Of Coolant ◽  
Accident Conditions ◽  
Cr Coating ◽  
The Impact ◽  
Positive Effect

To enhance the safety of nuclear power, the focus of researchers all around the world has recently mainly objected on the development of Accident Tolerant Fuels. Especially the Chromium coating of current Zirconium based cladding has been widely suggested and discussed for its immense positive effect on overall cladding properties. Nevertheless, it was observed that during the first stage of the Loss of Coolant Accident, cracks appear in the Cr coating due to its inability to tolerate higher plastic strain. Therefore, experimental methodology used in this article focuses on testing fuel cladding with damaged Cr coating after the high-temperature transient. The impact of cracks on degradation of cladding mechanical properties was observed using optical microscopy, ring compression test, microhardness, and evaluating hydrogen content and weight gain.

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