scholarly journals Evaluation of Heat Loss and Water Temperature in a Spent Fuel Pit

2012 ◽  
Vol 6 (2) ◽  
pp. 51-62 ◽  
Author(s):  
Chihiro YANAGI ◽  
Michio MURASE ◽  
Yoshitaka YOSHIDA ◽  
Takanori IWAKI ◽  
Takashi NAGAE
Keyword(s):  
Water Temperature ◽  
Heat Loss ◽  
Spent Fuel

scholarly journals ICONE19-43525 EVALUATION OF HEAT LOSS AND WATER TEMPERATURE IN A SPENT FUEL PIT

2011 ◽  
Vol 2011.19 (0) ◽  
pp. _ICONE1943-_ICONE1943
Author(s):  
Michio Murase ◽  
Chihiro Yanagi ◽  
Yoshitaka Yoshida ◽  
Takanori Iwaki ◽  
Takashi Nagae
Keyword(s):  
Water Temperature ◽  
Heat Loss ◽  
Spent Fuel

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

Effect of pressure on thermal insulation in humans wearing wet suits

1988 ◽  
Vol 64 (5) ◽  
pp. 1916-1922 ◽  
Author(s):  
Y. H. Park ◽  
J. Iwamoto ◽  
F. Tajima ◽  
K. Miki ◽  
Y. S. Park ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Water Temperature ◽  
Heat Loss ◽  
Thermal Insulation ◽  
Heat Production ◽  
Water Immersion ◽  
The Other ◽  
Body Parts ◽  
Metabolic Heat ◽  
Healthy Males

The present work was undertaken to determine the critical water temperature (Tcw), defined as the lowest water temperature a subject can tolerate at rest for 3 h without shivering, of wet-suited subjects during water immersion at different ambient pressures. Nine healthy males wearing neoprene wet suits (5 mm thick) were subjected to immersion to the neck in water at 1, 2, and 2.5 ATA while resting for 3 h. Continuous measurements of esophageal (T(es)) and skin (Tsk) temperatures and heat loss from the skin (Htissue) and wet suits (Hsuit) were recorded. Insulation of the tissue (Itissue), wet suits (Isuit), and overall total (Itotal) were calculated from the temperature gradient and the heat loss. The Tcw increased curvilinearly as the pressure increased, whereas the metabolic heat production during rest and immersion was identical over the range of pressure tested. During the 3rd h of immersion, Tes was identical under all atmospheric pressures; however, Tsk was significantly higher (P less than 0.05) at 2 and 2.5 ATA compared with 1 ATA. A 42 (P less than 0.001) and 50% (P less than 0.001), reduction in Isuit from the 1 ATA value was detected at 2 and 2.5 ATA, respectively. However, overall mean Itissue was maximal and independent of the pressure during immersion at Tcw. The Itotal was also significantly smaller in 2 and 2.5 ATA compared with 1 ATA. The Itissue provided most insulation in the extremities, such as the hand and foot, and the contribution of Isuit in these body parts was relatively small. On the other hand, Itissue of the trunk areas, such as the chest, back, and thigh, was not high compared with the extremities, and Isuit played a major role in the protection of heat drain from these body parts.

Modeling of the Heat Loss in a Thermal Sensor for Water Made of NTC Thick Film Segmented Thermistors

2013 ◽  
Vol 543 ◽  
pp. 334-337 ◽  
Author(s):  
Miloljub D. Lukovic ◽  
Maria Vesna Nikolic ◽  
Branka M. Radojcic ◽  
Obrad S. Aleksić
Keyword(s):  
Water Temperature ◽  
Thick Film ◽  
Heat Loss ◽  
Water Flow ◽  
Heat Balance ◽  
Heating Temperature ◽  
Balance Equations ◽  
Flow Meter ◽  
Exponential Factor ◽  
Self Heating

NTC thick film segmented thermistors were realized by screen printing of a low resistivity paste and conductive PdAg paste printed for electrodes. Two thick film thermistors as thermal sensors were placed in plastic tube housing connected to the water mains to form a calorimetric type of flow-meter, e.g. to measure the input water temperature and the thermistor self-heating temperature. Range constant voltage (RCV) was applied for self-heating thermistor power supply in different ranges of input water temperature. Modeling of the heat loss in the flow-meter for water was derived from heat balance equations for a self-heated thermistor in static water and in water flow conditions (static and dynamic thermistor temperature). Both temperatures (static and dynamic) were related to self-heating currents. The input water temperature was measured independently by a cold thermistor. Other parameters such as water thermal conductivity, thermistor exponential factor B and nominal thermistor resistance at room temperature were included in the thermistor heat balance equations. The logarithmic behavior of self-heating thermistors in the water flow enable modeling of heat loss as a function of static and dynamic currents related to static and dynamic thermistor temperatures. The model achieved was used in the fitting procedure of measured data of the flow-meter response.

scholarly journals Assessment of Thermal Protection of Life Rafts in Passenger Vessel Abandonment Situations

2008 ◽  
Author(s):  
Lawrence Mak ◽  
Andrew Kuczora ◽  
Michel B. DuCharme ◽  
James Boone ◽  
Rob Brown ◽  
...  
Keyword(s):  
Water Temperature ◽  
Heat Loss ◽  
Wave Height ◽  
Air Temperature ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Cold Water ◽  
Performance Criteria ◽  
Heat Conductance ◽  
Fishing Vessels

Inflatable life rafts are currently used on almost all passenger, fishing and commercial vessels, and offshore oil installations. Worldwide, life rafts are the primary evacuation system from fishing vessels with relatively small crews to large Roll on/Roll off passenger vessels with over a thousand passengers and crew. While International Maritime Organization (IMO) standards currently require inflatable life raft components to “provide insulation” or “be sufficiently insulated”, there are no performance criteria for these requirements (IMO, 1996). In a passenger ship abandonment situation in cold water, passengers may be wearing very little personal protective clothing. Therefore, life rafts provide the only significant thermal protection against the cold ocean environment while they await rescue. Manufacturers equip life rafts with an insulated floor to reduce heat loss from direct contact with the cold ocean water. The insulation provided is critically important for life raft occupants who have little protective clothing. The heat loss of unprotected persons is drastically increased if there is a layer of water on the floor as would likely be the case when someone climbs into the life raft from the ocean or if water is splashed into the life raft in heavy weather. Experiments were conducted in mild cold (16°C water temperature and 19°C air temperature) and cold conditions (5°C water temperature and 5°C air temperature) to assess the thermal protection of a 16-person, Safety of Life at Sea (SOLAS) approved, commercially available life raft. This paper presents results in the mild cold condition only. It has been found that the wave height effect may be ignored as a first approximation to reduce the number of environmental variables because the results demonstrated that wave height effect is less important with leeway. Heat conductance decreases considerably with floor inflation. Heat conductance is about the same with floor inflated 50% and 100%. The CO2 concentration in the 11-person test exceeded 5000 ppm in less than an hour inside the life raft, with closed canopy and no active ventilation. This hostile microclimate inside the life raft suggests that active ventilation at a known rate is required to keep the CO2 level at a safe controlled level when longer duration tests are to be conducted in the future. Wet clothing has a significant effect on occupant heat loss.

Safety Analysis of CPR1000 Spent Fuel Pool in Case of Loss of Heat Sink

2013 ◽  
Author(s):  
Haitao Wang ◽  
Li Ge ◽  
Jianqiang Shan ◽  
Junli Gou ◽  
Bo Zhang
Keyword(s):  
Water Temperature ◽  
Water Level ◽  
Heat Sink ◽  
Safety Analysis ◽  
Atmospheric Environment ◽  
Normal Operation ◽  
Spent Fuel ◽  
Pool Water ◽  
Fuel Assemblies ◽  
Spent Fuel Pool

The spent fuel pool (SFP) is mainly used for cooling spent fuel assemblies (SFAs) discharged from the reactor core. Besides, it can also shield the radiation. The decay heat can be removed through normal operation cooling system, otherwise it can only rely on the natural circulation in the pool when the coolant pump loses power or the heat exchanger fails. Thus the pool water temperature will continue to rise until it begins to boil. During this period, if no active cooling measures are triggered, the water level will gradually decrease as water boiling. Once the water level drops to the top of the fuel assemblies, the fuels begin to be exposed in the environment. In this paper, the CPR1000 spent fuel pool was chosen as the analysis object and the best estimate system thermal hydraulic code RELAP5 was employed to investigate the process in spent fuel pool in case of loss of heat sink. The results of calculations show that when losing two sets of cooling line, the increase in water temperature in the pool from 55 °C up to 100 °C takes approximately 9.1 h, the evaporation of water volume above the SFAs takes approximately 75.4 additional hours; while in case of losing one set of cooling line, the water temperature of the pool surface reaches 76.6 °C, at which the pool water would not going to boil under the atmospheric environment condition. The results of performed analysis are useful for safety analysis and storage of the SFAs, and can be used to provide a reference for spent fuel pool engineering design.

F113 Effects of Decay Heat Distribution on Water Temperature in Spent Fuel Pit

2014 ◽  
Vol 2014.19 (0) ◽  
pp. 159-160
Author(s):  
Chihiro YANAGI ◽  
Michio MURASE ◽  
Yoichi UTANOHARA
Keyword(s):  
Water Temperature ◽  
Heat Distribution ◽  
Spent Fuel ◽  
Decay Heat

Loss of Cooling Thermal Analysis for the Spent Fuel Pool of the Chinshan Nuclear Power Plant

2013 ◽  
Author(s):  
Yng-Ruey Yuann ◽  
Yen-Shu Chen ◽  
Ansheng Lin
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Water Temperature ◽  
Nuclear Power ◽  
Saturation Temperature ◽  
Spent Fuel ◽  
Pool Level ◽  
Commercial Operation ◽  
Spent Fuel Pool

The Chinshan Nuclear Power Plant owned and operated by the Taiwan Power Company is a twin-unit BWR-4 plant. Unit 1 and unit 2 began their commercial operation in 1978 and 1979, respectively. Since commercial operation, all the fuels discharged from reactor core at each cycle are stored in the spent fuel pool (SFP). An engineering analysis is performed to predict the SFP water temperature and pool water level during a postulated loss of forced cooling accident. A full-core discharged loading is considered, and the fuel assemblies are moved to the SFP just after 7 days of cooling. The pool temperature and level are calculated using lumped energy and mass balances. Calculation results show that the water temperature reaches the saturation temperature at 9.4 hours after the onset of the accident, and the pool level drops to the top of the active fuels at 76.8 hours. After the pool level drops to the top of the active fuels, the cladding temperature increases dramatically because the convective heat transfer of steam is much weaker than that of liquid water. The peak cladding temperature after fuel uncovery is calculated by detailed CFD simulations, and the results show that the peak cladding temperature reaches 600°C in 3 hours and 1200°C in 9.5 hours after the fuels are uncovered. Additionally, the check-board arrangement for fuels is also investigated. Through enhanced the radiation heat transfer, the check-board fuel arrangement can have slower heating rate for the fuels. For the Chinshan SFP, extra 2.5 hours can be gained by employing such an arrangement for necessary actions.

Effects of Decay Heat Distribution on Water Temperature in a Spent Fuel Pit and Prediction Errors With a One-Region Model

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Chihiro Yanagi ◽  
Michio Murase ◽  
Yoichi Utanohara
Keyword(s):  
Water Temperature ◽  
Temperature Increase ◽  
Natural Circulation ◽  
Three Dimensional ◽  
Power Supplies ◽  
Heat Distribution ◽  
Prediction Errors ◽  
Spent Fuel ◽  
Decay Heat ◽  
Ac Power

A prediction system with a one-region (1R) model was developed to predict water temperature in a spent fuel pit (SFP) after the shutdown of its cooling systems based on three-dimensional (3D) thermal-hydraulic behavior computed by using the computational fluid dynamics (CFD) software, FLUENT 6.3.26. The system was later extended to compute the water level in the SFP during the loss of all AC power supplies. This study aimed at confirming the applicability of the 1R model by the comparison of 3D computation results and 1R calculation results. Some of the effects that influence the SFP water temperature increase are decay heat and its distribution. Also, decay heat decreases with time, so for low decay heat, natural circulation force in the SFP becomes weak and the effect of heat loss to air for the water temperature increase will be relatively bigger than that for high decay heat. Therefore, in this study, the 3D computations with FLUENT 15.0 were done for four typical patterns of decay heat distribution and for three decay heat values (10, 5, and 1-MW). The computational results were compared to each other and evaluated. It was found that the effects of decay heat distribution were small on water temperature calculations, and the 1R model for SFP water was applicable to the prediction of SFP water temperature during the loss of all AC power supplies without consideration of the decay heat distribution.

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