Thermal Evaluation for a Ultra High Temperature Reactor With Pebble Type Fuels

2009 ◽  
Author(s):  
Motoo Fumizawa ◽  
Yuta Kosuge ◽  
Hidenori Horiuchi
Keyword(s):  
High Temperature ◽  
Power Density ◽  
Reactor Core ◽  
Coolant Temperature ◽  
Small Scale ◽  
Outlet Temperature ◽  
Fuel Temperature ◽  
System Pressure ◽  
High Temperature Reactor ◽  
Ultra High Temperature

This study presents a predictive thermal-hydraulic analysis with packed spheres in a nuclear gas-cooled reactor core. The predictive analysis considering the effects of high power density and the some porosity value were applied as a design condition for an Ultra High Temperature Reactor (UHTR). The thermal-hydraulic computer code was developed and identified as PEBTEMP. The highest outlet coolant temperature of 1316 °C was achieved in the case of an UHTREX at LASL, which was a small scale UHTR using hollow-rod as a fuel element. In the present study, the fuel was changed to a pebble type, a porous media. Several calculation based on HTGR-GT300 through GT600 were 4.8 w/cm3 through 9.6 w/cm3 respectively. As a result, the relation between the fuel temperature and the power density was obtained under the different system pressure and coolant outlet temperature. Finally, available design conditions are selected.

Thermal Hydraulics and Thermal Radiation for Ultra High Temperature Gas-Cooled Nuclear Reactor With Pebble Type Fuel

2005 ◽  
Author(s):  
Motoo Fumizawa
Keyword(s):  
High Temperature ◽  
Thermal Radiation ◽  
Surface Temperature ◽  
Radiation Flux ◽  
Coolant Temperature ◽  
Present Calculation ◽  
System Pressure ◽  
High Temperature Reactor ◽  
Type Fuel ◽  
Ultra High Temperature

This report presents the results of thermal-hydraulic analysis for the Ultra High Temperature Reactor Experiment (UHTREX) as well as the modular Gas Turbine High Temperature Reactor 300 MWth (HTGR-GT300) loaded with Pebble Type Fuel. A thermal-hydraulic computer code was developed that was named PEBTEMP. In order to compare the present PBR case with UHTREX, a calculation for HTGR-GT300 was carried out in the similar conditions with UHTREX i.e. the inlet coolant temperature of 871°C, system pressure of 3.45 MPa and power density of 1.3 W/cm3. The hot channel factor of 1.0, 1.1, 1.2, and 1.3 are chosen for the present calculation. As the result, the fuel temperature for the present PBR case is extremely low when compared to the UHTREX case. The evaluated temperature is compared to the data of conventional optical high temperature camera using the principle of the thermal radiation flux dependence upon surface temperature. Therefore, the present PBR system design will be named as NUHTREX i.e. New UHTREX. The evaluated temperature is compared to the data of conventional optical high temperature camera using the principle of the thermal radiation flux dependence upon surface temperature.

scholarly journals ANALISIS EFEK KECELAKAAN WATER INGRESS TERHADAP REAKTIVITAS DOPPLER TERAS RGTT200K

2015 ◽  
Vol 17 (1) ◽  
pp. 31 ◽  
Author(s):  
Zuhair Zuhair ◽  
Suwoto Suwoto
Keyword(s):  
High Temperature ◽  
Reactor Core ◽  
Negative Temperature ◽  
Fuel Temperature ◽  
Tube Heat Exchanger ◽  
Water Ingress ◽  
Effect Of Water ◽  
Positive Reactivity ◽  
High Temperature Reactor ◽  
Reactivity Coefficient

Dalam high temperature reactor, koefisien reaktivitas temperatur yang didesain negatif menjamin reaksi fisi dalam teras tetap berada di bawah kendali dan panas peluruhan tidak akan pernah melelehkan bahan bakar yang menyebabkan terlepasnya zat radioaktif ke lingkungan. Namun masuknya air (water ingress) ke dalam teras reaktor akibat pecahnya tabung penukar panas generator uap, yang dikenal sebagai salah satu kecelakaan dasar desain, dapat mengintroduksi reaktivitas positif dengan potensi bahaya lainnya seperti korosi grafit dan kerusakan material struktur reflektor. Makalah ini akan menganalisis efek kecelakaan water ingress terhadap reaktivitas Doppler teras RGTT200K. Kapabilitas koefisien reaktivitas Doppler untuk mengkompensasi reaktivitas positif yang timbul selama kecelakaan water ingress akan diuji melalui serangkaian perhitungan dengan program MCNPX dan pustaka ENDF/B-VII untuk perubahan temperatur bahan bakar dari 800K hingga 1800K. Tiga opsi kernel bahan bakar UO2, ThO2/UO2 dan PuO2 dengan tiga model kisi bahan bakar pebble di teras reaktor diterapkan untuk kondisi water ingress dengan densitas air dari 0 hingga 1.000 kg/m3. Hasil perhitungan memperlihatkan koefisien reaktivitas Doppler tetap negatif untuk seluruh opsi bahan bakar yang dipertimbangkan bahkan untuk posibilitas water ingress yang besar. Efek water ingress lebih kuat pada model kisi dengan fraksi packing lebih rendah karena lebih banyak volume yang tersedia untuk air yang memasuki teras reaktor. Efek water ingress juga lebih kuat di teras uranium dibandingkan teras thorium dan plutonium sebagai konsekuensi dari fenomena Doppler dimana absorpsi neutron di daerah resonansi 238U lebih besar daripada 232Th dan 240Pu. Secara keseluruhan dapat disimpulkan bahwa, koefisien Doppler teras RGTT200K mampu mengkompensasi insersi reaktivitas yang diintroduksi oleh kecelakaan water ingress. Teras RGTT200K dengan bahan bakar UO2, ThO2/UO2 dan PuO2 dapat mempertahankan fitur keselamatan melekat dengan cara pasif. Kata kunci: Water ingress, reaktivitas Doppler, RGTT200K   In high temperature reactor, the negative temperature reactivity coefficient guarantees fission reaction in the core remain under the control and decay heat will not melt the fuel which cause the release of radioactive substances into the environment. But the entry of water (water ingress) into the reactor core due to rupture of a steam generator tube heat exchanger, which is known as one of the design basis accidents, can introduce positive reactivity with other potential hazards such as graphite corrosion and damage of the reflector structure material. This paper will investigate the effect of water ingress accident on Doppler reactivity coefficient of RGTT200K core. The capability of the Doppler reactivity coefficient to compensate positive reactivity incurred during water ingress accident will be examined through a series of calculations with MCNPX code and ENDF/B-VII library for fuel temperature changes from 800K to 1800K. Three options of UO2, ThO2/UO2 and PuO2 fuel kernels with three lattice models of fuel pebble in the reactor core was applied for condition of water ingress with water density from 0 to 1000 kg/m3. The results of the calculations show that Doppler reactivity coefficient is negative for the entire fuel options being considered even for a large possibility of water ingress. The effects of water ingress becomes stronger in lattice model with lower packing fraction because more volume available for water entering the reactor core. The effect of water ingress is also stronger in the uranium core compared to thorium and plutonium cores as a consequence of the Doppler phenomenon where the neutron absorption in resonance region of 238U is greater than 232Th and 240Pu. It can be concluded overall that Doppler coefficient of RGTT200K core has capability to compensate the reactivity insertion introduced by water ingress accident. RGTT200K core with UO2, ThO2/UO2 and PuO2 fuels can maintain the inherently safety features in a passive way. Keywords: Water ingress, Doppler reactivity, RGTT200K

scholarly journals Nuclear policy-nuclear fuels for peaceful, safer co-generation and environmentally benign applications

2020 ◽  
Vol 9 (3) ◽  
pp. 724
Author(s):  
Syazwani Mohd Fadzil ◽  
Shafi Qureshi ◽  
Sekhar Basu ◽  
K. Kasturirangan ◽  
Anil Kakodkar ◽  
...  
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Reactor Core ◽  
Negative Temperature ◽  
Hydrogen Gas ◽  
Hydraulic Diameter ◽  
Nuclear Fuels ◽  
Spent Fuel ◽  
Fuel Temperature ◽  
Nuclear Policy

Here, safer nuclear fuels which can sustain in the high temperature and fluence environment of the reactor core are investigated to utilize nuclear energy peacefully. At Nuclear Fuel Complex in Hyderabad, nuclear fuels are being manufactured which are best suited for high temperature and fluence environment of the reactor core even in accidental scenarios. In this paper, nuclear fuels manufactured at NFC, Hyderabad are presented. The developed nuclear fuels have higher equivalent hydraulic diameter and breeding capability to produce U^233. Nuclear fuels having higher equivalent hydraulic diameter reduce the reactor core temperature substantially. These fuels have negative temperature coefficient of reactivity. Thus, in case of an accident, the fuel temperature never exceeds the safety limit. Therefore, the thermal heat available across the secondary of a heat exchanger can be utilized for different industrial processes. This allows the development of key technologies, such as safer co-generation of electricity and Hydrogen. The Three-Stage Indian Nuclear Power Program has been explained for nuclear disarmament. The product Hydrogen gas has been utilized in many ways for different applications. Moreover, the processing of iron ore with the energy obtained from the IHX secondary side, eliminates the burning of coals and CO2 emissions into the environment. Several radioisotopes have been developed for medical applications from spent fuel.  

High temperature reactor core physics and reactor dynamics

1990 ◽  
Vol 121 (2) ◽  
pp. 227-240 ◽  
Author(s):  
L. Wolf ◽  
W. Scherer ◽  
W. Giesser ◽  
W. Feltes
Keyword(s):  
High Temperature ◽  
Reactor Core ◽  
Reactor Dynamics ◽  
High Temperature Reactor
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