Heat transfer and fluid flow in porous fuel elements and thermal shields

El-Wakil, M. M.; Choudhury, W.U.; Marr, W.W.

doi:10.1016/0029-5493(71)90094-x

Cited by 12 publications

(7 citation statements)

References 4 publications

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“…This was accomplished by maximizing both the surface area of the external convective boundary and the convective heat transfer coefficient. The flow regime within the cooling jacket is fully developed turbulent, thus the convective heat transfer coefficient is maximized by selecting channel dimensions (within practical limits) that yield the largest Reynolds number [38]. …”

Section: Discussionmentioning

confidence: 99%

A simplified synthesis of the hypoxia imaging agent 2-(2-Nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-[18F]pentafluoropropyl)-acetamide ([18F]EF5)

Chitneni

Bida

Dewhirst

et al. 2012

Nuclear Medicine and Biology

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Introduction [18F]EF5 is a validated marker for PET imaging of tumor hypoxia. It is prepared by reacting a trifluoroallyl precursor with carrier-added [18F]F2 gas in trifluoroacetic acid (TFA) solvent. We report here an improved radiosynthesis and purification of [18F]EF5 by utilizing an electroformed nickel (Ni) target for [18F] F2 production, and Oasis® HLB cartridges for on-line solid phase extraction of [18F]EF5 prior to HPLC purification. Methods [18F]F2 was produced by deuteron bombardment of neon plus F2 in an Ni target, and bubbled through the radiolabelling precursor solution. Purification was achieved by extracting the contents of the crude reaction mixture onto Oasis HLB cartridges, and subsequently eluted onto a semi-preparative HPLC column for further separation. Purified [18F]EF5 was evaluated in small animal PET studies using HCT116 tumor xenografts in nude mice. Results The electroformed Ni target enabled recovery of >75% of the radioactivity from the cyclotron target, resulting in 16.2±2.2 GBq (438±58 mCi) of [18F]F2 available for the synthesis. Use of Oasis cartridges yielded a less complex mixture for purification. On average, 1140±200 MBq (30.8±5.4 mCi) of [18F]EF5 were collected at EOS. Small animal PET imaging studies showed specific retention of [18F]EF5 in tumors, with tumor-to-muscle ratios of 2.7±0.3 at about 160 min after injection. Conclusion A simple procedure has been developed for the routine synthesis of [18F]EF5 in amounts and purity required for clinical studies. This new method avoids the need for TFA evaporation and also enables facile automation of the synthesis using commercially available radiosynthesis modules.

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Section: Discussionmentioning

confidence: 99%

A simplified synthesis of the hypoxia imaging agent 2-(2-Nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-[18F]pentafluoropropyl)-acetamide ([18F]EF5)

Chitneni

Bida

Dewhirst

et al. 2012

Nuclear Medicine and Biology

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“…Thermal conductivity values of UO 2 and ThO 2 fuel rods are shown, depending on temperature in Table 5.1 of Reference [27]. These values are defined analytically in W cm À1 0 C À1 as follows: The UO 2 has the disadvantage that its thermal conductivity is the lowest of all kinds of nuclear fuels; metal, carbide, nitride [1].…”

Section: à2mentioning

confidence: 99%

Analysis of temperature distribution, burn-up and breeding parameters in nuclear fuel rod in fusion-fission reactor system fueled with mixed ThO2-UO2 fuel

Ipek

2010

Int. J. Energy Res.

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SUMMARYTemperature distribution in nuclear fuel rod, burn-up (BU), possibility of nuclear fuel rejuvenation and breeding parameters are investigated for different coolants under various first wall loads (Pw 5 2, 5 and 7 MW m À2 ) in a deuterium-tritium driven fusion-fission reactor system, fueled with mixed UO 2 -ThO 2 fuel. The fuel mixture is considered to be mixed with various mixture fractions.A (D-T) fusion reactor acts as an external high energetic (14.1 MeV) neutron source. The plasma chamber dimension, DR, with a line fusion neutron source is 300 cm. In the tritium breeding zone of the blanket Li 2 O is used and blanket is reflected by graphite for neutron economy. The fissile fuel zone is considered to be cooled with three different coolants [gas (He, CO 2 ), Flibe (Li 2 BeF 4 ) and natural lithium (Li)] with the volumetric ratio of coolant-to-fuel [e 5 (V coolant /V fuel ) 5 1:1 (45.515% coolant, 45.515% fuel and 8.971% clad)] for nuclear heat transfer. The behavior of the blankets fueled with mixed fuel mentioned above are observed for 48 months for discrete time intervals of Dt 5 15 days and by a plant factor of 75%. The fissile fuel zone, containing 10 fuel rod rows in the radial direction, covers the cylindrical fusion plasma chamber. The fissile fuel breeding occurs through the neutron capture reaction in the 232 Th (ThO 2 ), in the 238 U (UO 2 ) isotopes. As a result of the calculations, fuel mixtures having the best performance parameters have been obtained as follows for different coolants and under the 7 MW m À2 first wall load during operation period without reaching the melting point:The blanket fueled with 70 wt% UO 2 À30 wt% ThO 2 for Flibe (Li 2 BeF 4 ) coolant The blanket fueled with 80 wt% UO 2 À20 wt% ThO 2 for Gas (He, CO 2 ) coolant The blanket fueled with 90 wt% UO 2 À10 wt% ThO 2 for natural lithium (Li) coolantClad surface temperature T c controlled by coolant velocity is taken between certain operation temperatures (T c 5 200, 300, 400, 500 and 6001C). The best Cumulative Fissile Fuel Enrichment (CFFE) grade of the nuclear fuel calculated as the sum of the isotopic ratios of all fissile materials ( Pu) is obtained in Flibe (Li 2 BeF 4 ) coolant blankets, followed by Gas (He, CO 2 ), whereas natural lithium (Li) coolant shows a poor rejuvenation performance in all fuels. CFFE reaches the maximum value (CFFE 5 10.6200%) in blanket cooled with Li 2 BeF 4 coolant, followed by gas coolant with 9.0319% and natural lithium coolant with 7.9863% without reaching the melting point (T max 5 T m 4 28301C) of the fuel materials. At this point, the maximum temperature in centerline of the fuel rod (T m ) reach to 2727.571C in blanket cooled with Li 2 BeF 4 coolant. However, in the blanket fueled with pure UO 2 fuel and cooled with Flibe, CFFE and Centerline Temperature of the fuel rods (T m ) are reached to 9.7277% and 2811.131C respectively at the end of 39 months. In the blanket fueled with pure UO 2 and cooled with gas, CFFE and Centerline Temperature of the fuel rods (T m ) are reached to 7...

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“…It was caused by low temperature absorption due to the existence of element H in the moderator (H 2 O). The thermal equilibrium will be achieved when the neutrons are slowed down in the moderator [7].…”

Section: Model Parameter and Simulationmentioning

confidence: 99%

State space modeling of reactor core in a pressurized water reactor

Ashaari

Ahmad

Shamsuddin

et al. 2014

AIP Conference Proceedings

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Abstract. The power control system of a nuclear reactor is the key system that ensures a safe operation for a nuclear power plant. However, a mathematical model of a nuclear power plant is in the form of nonlinear process and time dependent that give very hard to be described. One of the important components of a Pressurized Water Reactor is the Reactor core. The aim of this study is to analyze the performance of power produced from a reactor core using temperature of the moderator as an input. Mathematical representation of the state space model of the reactor core control system is presented and analyzed in this paper. The data and parameters are taken from a real time VVER-type Pressurized Water Reactor and will be verified using Matlab and Simulink. Based on the simulation conducted, the results show that the temperature of the moderator plays an important role in determining the power of reactor core.

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Heat transfer and fluid flow in porous fuel elements and thermal shields

Cited by 12 publications

References 4 publications

A simplified synthesis of the hypoxia imaging agent 2-(2-Nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-[18F]pentafluoropropyl)-acetamide ([18F]EF5)

A simplified synthesis of the hypoxia imaging agent 2-(2-Nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-[18F]pentafluoropropyl)-acetamide ([18F]EF5)

Analysis of temperature distribution, burn-up and breeding parameters in nuclear fuel rod in fusion-fission reactor system fueled with mixed ThO2-UO2 fuel

State space modeling of reactor core in a pressurized water reactor

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