scholarly journals Analysis of Combustion and Smoke Characteristics According to the Aging of Class 1E Cables in Nuclear Power Plants

2021 ◽  
Vol 35 (1) ◽  
pp. 20-27
Author(s):  
Seok-Hui Lee ◽  
Min-Ho Kim ◽  
Sangkyu Lee ◽  
Ju-Eun Lee ◽  
Min-Chul Lee
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Total Heat ◽  
Total Heat Release ◽  
Char Layer ◽  
Cone Calorimeter Test

In this study, combustion and smoke characteristics according to the aging of class 1E cables in nuclear power plants were analyzed through a cone calorimeter test. In the case of combustion characteristics, during the early period, which was the first peak of the heat release rate, the peak value of the non-aged cable was higher by approximately 20-50 kW/m<sup>2</sup> than that of aged cables. However, in the mid-late periods, which was the second peak, the value of the aged cables were higher than the non-aged cable due to the decrease in flame retardant performance with aging deterioration. In addition, the duration of the char layer of the aged cables was shortened by 200 s than that of the non-aged cables due to the unstable formation of char layer. The total heat release measured was approximately 1.4 times higher in the aged cables than in the non-aged cables. In the case of smoke characteristics, the smoke production rate and total smoke release show a similar trend with the heat release rate and total heat release. The total smoke release of the aged cables was measured to be higher than that of the non-aged cables. The tendency of the smoke factor increased with aging deterioration, and the values of the smoke factor in the aged cables beyond 4 years were approximately 1.76-2.0 times different from those in the non-aged cables. Consequently, the smoke risk increased with aging deterioration. Therefore, the risk of heat and smoke release increased as aging progressed.

Numerical and Experimental Study of Merging Fires in Square Arrays

2007 ◽  
Author(s):  
Kohyu Satoh ◽  
Liu Naian ◽  
Liu Qiong ◽  
K. T. Yang
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Forest Fires ◽  
Large Scale ◽  
Gas Flow ◽  
Fire Spread ◽  
Total Heat ◽  
Total Heat Release ◽  
Convective Gas Flow

In large-scale forest fires and city fires, merging fires and fire whirls have often been observed, which cause substantial casualties and property damages. It is important to know particularly where and under what conditions of weather such merging fires and fire whirls appear in cities or forests. However, there have been no adequate answers, since the detailed physical characteristics about them are not fully clarified yet, although previous studies have examined the phenomena of merging flames. Therefore, we have carried out preliminary studies and found that the merged tall fires can enhance the fire spread, and developed a method to analyze burn-out data of fire arrays. If sufficient knowledge can be obtained by relevant experiments and numerical computations, it may be possible to mitigate the damages due to merged fires and fire whirls. The objective of this study is to investigate the merging conditions of fires in square arrays in laboratory experiments and also by CFD numerical simulations, varying the size of square array, inter-fire distance and heat release rate, to judge ‘unmerged’ or ‘merged’ conditions in the fire array. It has been found that the fire merging is dependent on the inter-fire distance in the array and also on the total heat release rate of all fires surrounding the center region of the array. Also found that the experimental and simulated results on the merged and unmerged cases in the fire array, as affected by the total heat release rate and the inter-fire distance, which control the convective gas flow into the array, behave very similarly. Therefore, it can be concluded that the fire merging in array fires are highly based on the convection in the flow field due to fires and can be predicted by simple CFD simulations.

scholarly journals Influence of Thermal Aging on the Combustion Characteristics of Cables in Nuclear Power Plants

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2003
Author(s):  
Min Ho Kim ◽  
Hyun Jeong Seo ◽  
Sang Kyu Lee ◽  
Min Chul Lee
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Nuclear Power ◽  
Power Plants ◽  
Combustion Characteristics ◽  
Aging Period ◽  
Toxic Gases

In this study, the combustion characteristics and emission of toxic gases of a non-class 1E cable in a nuclear power plant were investigated with respect to the aging period. A thermal accelerated aging method was applied using the Arrhenius equation with the activation energy of the cables and the aging periods of the cables set to zero, 10, 20, 30 and 40 years old by considering the lifetime of a nuclear power plant. According to ISO 5660-1 and ISO 19702, the cone calorimeter Fourier transform infrared spectroscopy test was performed to analyze the combustion characteristics and emission toxicity. In addition, scanning electron microscopy and an energy dispersive X-ray spectrometer were used to examine the change in the surface of the sheath and insulation of the cables according to the aging periods. To compare quantitative fire risks at an early period, the fire performance index (FPI) and fire growth index (FGI) are derived from the test results of the ignition time, peak heat release rate (PHRR) and time to PHRR (tPHRR). When comparing FPI and FGI, the fire risks decreased as the aging period increased, which means that early fire risks may be alleviated through the devolatilization of both the sheath and insulation of the cables. However, when comparing heat release and mass loss, which represent the fire risk at the mid and late period, fire intensity and severity increased with the aging period. The emission of toxic gases coincided with the results obtained from the heat release rate, which confirms that the toxicity of non-aged cables is higher than that of aged cables. From the results, it can be concluded that the aging period significantly affects both the combustion characteristics and toxicity of the emission gas. Therefore, cable degradation with aging should be considered when setting up reinforced safety codes and standards for cables and planning proper operation procedures for nuclear power plants.

Research on the Combustibility of PI Needle Punched Nonwovens by Cone Calorimeter

2011 ◽  
Vol 332-334 ◽  
pp. 1335-1338
Author(s):  
Shu Gan Li ◽  
Xiao Ning Jiao ◽  
Qing Long Jia
Keyword(s):  
Mass Loss ◽  
Heat Release ◽  
Heat Release Rate ◽  
Fire Resistance ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Ignition Time ◽  
Total Heat ◽  
Total Heat Release ◽  
Resistance Performance

This paper demonstrates the combustibility of PI needle punched nonwovens by Cone Calorimeter. Ignition parameter, heat release parameters, smoke and toxicity parameters and mass loss parameters of the fabric were obtained from it. It was found that ignition time is 38 s; the peak of heat release rate is 65 kW/m2; total heat release is 7 MJ/m2; smoke release rate is 1.5 L/s; smoke factor is 1.3 MW/m2 and mass lose rate is 73.3%. Therefore the results show that PI needle punched nonwovens has excellent fire-resistance performance.

Research on Fire Retardant Performance of Chinese Fir with the Compound of Disodium Octaborate Tetrahydrate and SiO2 Gels

2011 ◽  
Vol 477 ◽  
pp. 175-184
Author(s):  
Qing Qing Ye ◽  
Xiao Qian Qian ◽  
Jun Ying Lai
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Ignition Time ◽  
Fire Retardant ◽  
Chinese Fir ◽  
Total Heat ◽  
Fire Retardancy ◽  
Total Heat Release ◽  
Disodium Octaborate Tetrahydrate

The environmental fire retardant mentioned in this paper was compounded of disodium octaborate tetrahydrate and silicon dioxygen(SiO2)gels. Specimens of Chinese fir were impregnated with the compound by pressure and its fire retardant performance was studied. Results showed that, the anti-loss performance of disodium octaborate tetrahydrate was improved obviously. Compared with the untreated specimen, total heat release of the treated specimens decreased by 44.5% on average, while heat release rate decreased by 50.85% on average and ignition time prolonged obviously, which indicates that this compound possess good fire retardancy effect

scholarly journals Cone calorimetric fire properties and thermal analysis of polyester-banana peduncle fibre composite fused with bio-fire retardant additive

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Ernest Mbamalu Ezeh
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Research Work ◽  
Fire Retardant ◽  
Total Heat ◽  
Total Heat Release ◽  
Reinforcement Material

Abstract Background Lately, thermoplastic and thermoset polymers are integrated with natural fillers to harvest composites. Due to an excellent property profile, these composites find wide applications in engineering fields. This research work aimed to investigate the parameters that influence the thermal degradation of Polyester-Banana peduncle fibre-reinforced composite incorporated with cow horn ash particle (CHAp) as a fire retardant additive and optimize the total heat produced for the smaller the better. The major instruments used in this study were cone calorimeter and the thermogravimetric analyser. Result The parameters considered were time, reinforcement type, and weight per cent of reinforcement material. The composites were made by varying the ratios of CHAp and BPF in the polyester matrix from 0:0, 2.5:2.5, 5:5 and 7.5:7.5 and 10:10 weight per cent. The flammability properties of the developed composites were examined, using a cone calorimeter. The controlling parameters were analysed using the Taguchi robust design method. The ANOVA showed that time had the greatest influence on the total heat release rate (81.72%). The weight per cent reinforcement type (10.37%) and reinforcement type (5.28%) had smaller influences on the heat release rate. The S/N ratio obtained, using optimal testing shows that time had the greatest influence on the total heat release rate, followed by weight per cent of reinforcement type, while reinforcement type had the least influence. The corresponding multiple regression models for total heat released revealed that the total heat release rate increased with an increase in time and reinforcement type and decreased with an increase in weight per cent of the fire retardant additive material. Conclusion This work indicated that the parameter design of the Taguchi method provided an efficient methodology for the analyses of the effects of thermal degradation parameters of composites. The controlling parameters of time, the weight of reinforcement material and the type of reinforcement material had significant contributions to the value of heat production during composites thermal decomposition. Time had the greatest contribution, followed by the weight of reinforcement type, and type of reinforcement material.

Cone Calorimeter Analysis on the Fire-Resistant Properties of FRW Fire-Retardant Particleboard

2011 ◽  
Vol 311-313 ◽  
pp. 2142-2145 ◽  
Author(s):  
Ying Tao Liu
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Fire Retardant ◽  
Total Heat ◽  
Total Heat Release ◽  
High Increase

The fire-resistant properties of FRW fire-retardant particleboard and untreated particleboard had been measured under a heat flux of 75 kW/m2 by cone calorimeter (CONE). Through the compare between FRW fire-retardant particleboard and untreated particleboard, the influence on the particleboard by FRW fire retardant had been indicated. The results showed that the indexes of heat release rate (HRR), total heat release (THR) and efficient heat combustion (EHC) etc of FRW fire-retardant particleboard were obviously reduced contrast to the ordinary particleboard, but the char-forming rate had a high increase.

Heat Release Performance of the Flame Retardant Rigid Polyurethane Insulation Foam

2013 ◽  
Vol 785-786 ◽  
pp. 131-137
Author(s):  
Ze Jiang Zhang ◽  
Li Jun Li ◽  
Feng Li ◽  
Jin He ◽  
Zi Qiong Gan
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Release Rate ◽  
Ignition Temperature ◽  
Flame Retardants ◽  
Total Heat ◽  
Antimony Trioxide ◽  
Rigid Polyurethane Foam ◽  
Total Heat Release

Influence of different flame retardants on the heat release performance of the rigid polyurethane foam (RPF) was studied in this paper. It was found that adding antimony trioxide (ATT) in RPF, heat release rate of RPF was slightly reduced, total heat release was significantly decreased but peak of heat release temperature was decreased. Therefore, ATT was not an excellent flame retardant for RPF. When adding ammonium polyphosphate (APP) in RPF, total heat release of RPF was significantly decreased, ignition temperature was significantly improved and heat release rate was not changed. Melamine polyphosphate (MPOP) could quickly reduce total heat release of RPF so its flame retardant effect was the best. Nitrogen-based flame retardants could reduce peak of heat release rate of RPF. APP, MPOP and nitrogen-based flame retardants were all better flame retardants for RPF. Small amount of magnesium hydroxide (MH) could increase total heat release of RPF.

Effect of Radiation Deterioration on Class 1E Cable Fire

2020 ◽  
Vol 34 (6) ◽  
pp. 1-7
Author(s):  
Min Ho Kim ◽  
Seok Hui Lee ◽  
Sang Kyu Lee ◽  
Ju Eun Lee ◽  
Min Chul Lee
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Nuclear Power ◽  
Critical Factor ◽  
Toxicity Index ◽  
Total Mass Loss ◽  
Cone Calorimeter Test ◽  
Heat Penetration ◽  
Cable Fire

In this study, the effect of radiation deterioration on cable fire for a type of class 1E cable for a nuclear power plant was investigated. Combustion and smoke characteristics were compared via a cone calorimeter test (ISO 5660-1), and the toxicity index of the toxic gas emitted during combustion was analyzed by following the NES 713 standard. The peak heat release rate of the irradiated cable was measured to be approximately 38 kW/m<sup>2</sup> higher than that of the non-irradiated cable. Additionally, the heat release rate of the irradiated cable temporarily increased during a certain period. This can be ascribed to the continuous pyrolysis and heat penetration as a result of the unstable formation of the char layer. The total heat release of the irradiated cable was measured to be approximately 2.2 times higher than that of the non-irradiated cable. A corresponding increase of ~2.8% in the total mass loss was observed. In the case of smoke characteristics, the irradiated cable was measured to be 2.3 times higher in the smoke parameter and 3.8 times higher in the smoke factor compared to the non-irradiated cable. For the toxicity index, only CO was detected above the critical factor in the non-irradiated cable, whereas both CO and HBr were detected above their critical factors in the irradiated cable.

Calculations of the Heat Release Rate by Oxygen Consumption for Various Applications

1984 ◽  
Vol 2 (5) ◽  
pp. 380-395 ◽  
Author(s):  
W.J. Parker
Keyword(s):  
Oxygen Consumption ◽  
High Temperature ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Tests ◽  
Total Heat Release ◽  
Exhaust Duct ◽  
Closed Systems ◽  
Gas Burner

The calculation of heat release rate by oxygen consumption is based on the assumption that all materials release approximately the same amount of heat per unit mass of oxygen consumed. This technique is now being employed to determine the heat release rate of materials in various heat release rate cal orimeters. Other uses include the heat release rate of assemblies in the fire en durance furnaces and the total heat release rate in room fire tests. These dif ferent applications lead to different experimental procedures which require dif ferent formulas. The experimental choices or constraints include open or closed systems, paramagnetic or high temperature oxygen analyzers, CO2 analyzers or CO2 traps, and the use of a gas burner whose heat release rate must be deducted from the total. Various assumptions about CO levels in the exhaust duct and vitiation and humidity in the incoming air are made. General formulas for the heat release rate by oxygen consumption are developed in this paper from which the formulas for specific applications can easily be derived.

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