MARS-KS Calculations for ATLAS 6-Inch Cold Leg Break (SBLOCA) Test

2012 ◽  
Author(s):  
Dong-Gu Kang ◽  
Joo-Sung Kim ◽  
Seung-Hoon Ahn
Keyword(s):  
Water Level ◽  
Liquid Level ◽  
Injection Time ◽  
Secondary System ◽  
Water Flows ◽  
Sequence Of Events ◽  
Loss Of Coolant Accident ◽  
Integral Effect ◽  
Sudden Decrease ◽  
Transient Thermal

An integral effect test on the SBLOCA (Small-Break Loss of Coolant Accident) aiming at 6-inch cold leg bottom break, SB-CL-09, was conducted with the ATLAS on November, 13, 2009 by KAERI. In this study, the calculations using MARS-KS V1.2 code were conducted for 6-inch cold leg break test of ATLAS (SB-CL-09) to assess MARS-KS code capability to simulate the transient thermal-hydraulic behavior for SBLOCA. The steady state was determined by conducting a null transient calculation and the errors between the calculated and measured values are acceptable for almost primary/secondary system parameters. The sequence of events except the location of loop seal clearing (LSC) and SIT injection time was predicted relatively well. The predicted pressurizer pressure agrees relatively well with the experimental data and the predicted break flow and mass are in good agreement with experiment. In MARS-KS calculation, the decrease of core collapsed water level is predicted well in blowdown phase, but just before LSC, water level is higher than experiment. However, the sudden decrease and increase of water level at the LSC are predicted qualitatively. After LSC, there is another water level dip at SIT injection time which is not in experiment. It is considered that this phenomenon is caused by rapid depressurization of downcomer due to significant condensation rate of vapor in downcomer when SIT water flows in it. For the downcomer water level, before the SIT injection time, water level is predicted well, however, it is significantly over-predicted at SIT injection time after SIT water flows in downcomer. Predicted cladding temperature generally agrees well with the experiment, while there is peak at SIT injection time in calculation which is not in experiment. The loop seals of 1A, 2B intermediate leg are cleared around 400 seconds in experiment, while only that of 1A is cleared in MARS-KS calculation at the same time. In conclusions, MARS-KS code has good capabilities to simulate cold leg break SBLOCA, however, there are some discrepancies in quantitatively predicting the steam generator secondary pressure, core collapsed liquid level, downcomer liquid level, and so on. Therefore, MARS-KS code including interfacial condensation model needs to be improved to predict more accurate results.

Asymmetry Analysis of Water Level Measured on Two Ends of Drum Boiler

2010 ◽  
Vol 148-149 ◽  
pp. 1421-1426
Author(s):  
Bo Zhou ◽  
Chao Yang Fei
Keyword(s):  
Power Plant ◽  
Water Level ◽  
Field Data ◽  
Natural Circulation ◽  
Feed Water ◽  
Related Factors ◽  
Drum Boiler ◽  
Measurement Systems ◽  
Water Flows ◽  
Asymmetry Analysis

Control of the water level in the drum of the boiler system is a critical operation consideration, because asymmetric dynamics of water level measured leads to measuring errors. This phenomenon is testified by field data from a 400t/h drum boiler with natural circulation in a power plant of China. Some equations are developed and several related factors are focused on, and two of which become critical ones accounting for asymmetry of measured value. With the study of structure of distribution pipes in drum, it is found that feed-water flows distributed on the opposite ends of drum are obviously asymmetric, where measurement systems are positioned. When more feed-water is supplied at one end of drum, the rate of steam in water and water temperature become lower, and measured level get higher. Through the simulation, the important factors for asymmetric of water level are found out, which is necessary to minimize the measuring errosrs.

Preliminary Probabilistic Safety Assessment of the IRIS Plant

2002 ◽  
Author(s):  
Yuko O. Mizuno ◽  
Katsunori Ogura ◽  
Hisashi Ninokata ◽  
Lawrence E. Conway
Keyword(s):  
Safety Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Heat Removal ◽  
Primary System ◽  
Event Tree ◽  
Secondary System ◽  
Probabilistic Safety Assessment ◽  
Loss Of Coolant Accident ◽  
Probabilistic Safety

A preliminary level-1 probabilistic safety assessment of the IRIS plant has been performed. The first focus is on five internal initiating events, such as primary system break (loss-of-coolant accident and steam generator tube rupture) and transients (secondary system line break and loss-of-off-site power). In this study, the event tree for each initiating event was developed and the fault tree analysis of the event tree headings was carried out. In particular, since one of the IRIS safety systems, the passive emergency heat removal system, is unique to the IRIS plant and its reliability is key to the core damage frequency evaluation, it received more extensive fault-tree development. Finally the dominant sequences that lead to severe accidents and the failures in the main and support systems are identified.

scholarly journals Natural and Anthropogenic Factors Impact on the Amur River Bed Passage Ability near Khabarovsk during floods passing

2020 ◽  
pp. 66-82
Author(s):  
Keyword(s):  
Water Level ◽  
Construction Cost ◽  
Anthropogenic Factors ◽  
Channel Processes ◽  
Amur River ◽  
Water Flows ◽  
River Bed ◽  
The Amur River ◽  
The Given ◽  
Natural And Anthropogenic Factors

The article discusses the range of the Amur River maximal annual levels and water flows near Khabarovsk over the whole period of observations (1896–2019), quantity of outstanding and catastrophic floods. In compliance with references, the articles considered the main characteristics forming the channel processes at the given reach of the river. We have estimated the natural and anthropogenic factors impact on the water flows and levels passage ability in case of catastrophic floods and increasing of the protective facilities’ construction cost due to the water level extreme increase caused by anthropogenic factors. We have proposed a method of the maximal water level forecasting near the Khabarovsk water hub.

scholarly journals Smelt spout corrosion in a recovery boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (8) ◽  
pp. 39-45
Author(s):  
JULIO CÉSAR TÔRRES RIBEIRO ◽  
MARCELO CARDOSO ◽  
HONGHI TRAN
Keyword(s):  
Water Flow ◽  
Service Failure ◽  
Cooling Water ◽  
Electrical Energy ◽  
Energy System ◽  
Extensive Investigation ◽  
Water Flows ◽  
Sequence Of Events ◽  
Recovery Boiler

Severe corrosion led to an in-service failure of one of the six spouts on a recovery boiler at Cenibra. The failure resulted in a large amount of cooling water entering the boiler and contacting smelt around the spout opening, but fortunately no smelt-water explosion occurred. An extensive investigation was conducted to determine the causes of the spout failure. The failure was caused by insufficient cooling water flow to the smelt spout, which, in turn, was caused by a sequence of events that occurred after a general blackout of an electrical energy system at the mill. The experience has led to the development and placement of operating and maintenance procedures that ensure adequate cooling water flows to smelt spouts to prevent future failures.

scholarly journals Analysis of Floodplain Dynamics in the Atrato River Colombia Using SAR Interferometry

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 875 ◽  
Author(s):  
Sebastián Palomino-Ángel ◽  
Jesús A. Anaya-Acevedo ◽  
Marc Simard ◽  
Tien-Hao Liao ◽  
Fernando Jaramillo
Keyword(s):  
Surface Water ◽  
Water Level ◽  
River Basin ◽  
Sar Interferometry ◽  
Hydrological Connectivity ◽  
Mining Activities ◽  
Alos Palsar ◽  
Water Flows ◽  
Main River Channel ◽  
Synthetic Aperture Radars

Floodplain water flows have large volumetric flowrates and high complexity in space and time that are difficult to understand using water level gauges. We here analyze the spatial and temporal fluctuations of surface water flows in the floodplain of the Atrato River, Colombia, in order to evaluate their hydrological connectivity. The basin is one of the rainiest areas of the world with wetland ecosystems threatened by the expansion of agriculture and mining activities. We used 16 Differential Interferometric Synthetic Aperture Radars (DInSAR) phase observations from the ALOS-PALSAR L-band instrument acquired between 2008–2010 to characterize the flow of surface water. We were able to observe water level change in vegetated wetland areas and identify flooding patterns. In the lower basin, flow patterns are conditioned by fluctuations in the levels of the main river channel, whereas in the middle basin, topography and superficial channels strongly influence the flow and connectivity. We found that the variations in water level in a station on the main channel 87 km upstream explained more than 56% of the variations in water level in the floodplain. This result shows that, despite current expansion of agriculture and mining activities, there remain significant hydrological connectivity between wetlands and the Atrato River. This study demonstrates the use of DInSAR for a spatially comprehensive monitoring of the Atrato River basin hydrology. For the first time, we identified the spatiotemporal patterns of surface water flow of the region. We recommend these observations serve as a baseline to monitor the potential impact of ongoing human activities on surface water flows across the Atrato River basin.

TEMPERATURE AND WATER LEVEL MEASUREMENT OF LIQUID IN A TANK USING FIBER BRAGG GRATING

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Odai Falah Ameen ◽  
Marwan Hafeedh Younus ◽  
M. S. Aziz ◽  
RK Raja Ibrahim
Keyword(s):  
Water Level ◽  
Fiber Bragg Grating ◽  
Linear Response ◽  
Liquid Level ◽  
Laser Source ◽  
Bragg Grating ◽  
Bragg Wavelength ◽  
Work Measurement ◽  
Level Measurement ◽  
Fbg Sensors

In this work, measurement of temperature and liquid level were performed simultaneously using fiber Bragg grating (FBG) sensors. A multi-channel Fibre Interrogator with built-in ASE laser source operating around 1552 to 1568 nm was employed to record a shift in Bragg wavelength due to contribution from both temperature and hydrostatic pressure of liquid weight in the tank. Results show a linear response between liquid level and temperature readings against the shift in Bragg wavelength for liquid level up to 85 cm in height and the temperature range of 27 to 77 oC. The sensitivity of the sensor head for water level measurement is 10.57 pmcm-1, while the sensitivity for temperature measurement is 11.28 pm/oC respectively.

Performance of a Spray Pond for Nuclear Power Plant Ultimate Heat Sink

1977 ◽  
Vol 99 (4) ◽  
pp. 650-656
Author(s):  
V. E. Schrock ◽  
G. J. Trezek ◽  
L. R. Keilman
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Thermal Performance ◽  
Heat Sink ◽  
Nuclear Power ◽  
Field Tests ◽  
Computer Code ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Transient Thermal

Spray ponds have become an attractive method of providing the “ultimate heat sink”, i.e., the assured means of dissipating heat from a nuclear power plant. Two redundant spray ponds were the choice for this service in the Rancho Seco Nuclear Generating Station owned by Sacramento Municipal Utility District. This paper describes the results of full scale field tests of the Rancho Seco ponds which were conducted to verify the thermal performance, drift loss characteristics, and the capability to sustain the cooling requirements for a period of 30 days following a loss-of-coolant accident (LOCA). Correlations of local and average nozzle efficiency and of the drift loss are presented. A computer code was developed for the transient thermal performance of the pond. After verification the code was used to predict performance following LOCA under adverse meteorological conditions based on weather records.

Multidimensional Analysis of UPTF Upper Plenum Injection Test With MARS-KS Code

2009 ◽  
Author(s):  
Kyung Won Lee ◽  
Yong Jin Cho ◽  
Seung Hoon Ahn
Keyword(s):  
Water Level ◽  
Fluid Model ◽  
Flow Region ◽  
Multidimensional Analysis ◽  
Flow Area ◽  
Core Flow ◽  
Injection Test ◽  
The Core ◽  
Loss Of Coolant Accident ◽  
Calculation Results

This study aims to assess the multi-dimensional fluid model of MARS-KS (KINS standard version of MARS) code. The UPTF upper plenum injection test (UPI Test, Test No. 20) is modeled with the MARS in order to assess the code capability for predicting the multi-dimensional behavior of UPI water in the upper plenum during a reflood phase of large break loss-of-coolant accident. The coolant piping is simulated by one-dimensional components, while the reactor vessel is modeled by the cylindrical multi-dimensional component with five rings in radial direction, eight sectors in azimuthal direction, and fourteen axial levels. The results of MARS calculation are compared with the experimental data of UPTF test, particularly the ECC downflow area in the core flow area, the water carryover rate to hot legs, and the water level distribution in upper plenum. The calculation results indicate that the size of the downflow area is about 16.7% of the core flow area, comparable to the result of 10% in UPTF test. The MARS overestimates the amount of water carryover to the hot legs. As seen in the UPTF UPI test, the collapsed water level formed in the upper plenum is uniform at the entire core flow area, except at the down flow region where more water accumulates. These results demonstrate that MARS can provide a reasonable prediction of multi-dimensional behavior of UPI water in the upper plenum.

Sign in / Sign up

Export Citation Format

Share Document