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Ditemukan 3 dokumen yang sesuai dengan query
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Pungky Ayu Artiani
Pemodelan dan simulasi tangki penyimpanan pada instalasi penyimpanan sementara bahan bakar nuklir bekas high temperature reactor 10 (HTR10) = Modeling and simulation of storage tank in interim storage for spent fuel of high temperature reactor 10( HTR 10)
"[ABSTRAK
Limbah Bahan Bakar Nuklir Bekas (BBNB) merupakan salah satu limbah yang dihasilkan dalam pengoperasian reaktor nuklir. Limbah ini masih menghasilkan produk fisi dan panas hasil reaksi yang masih tinggi sehingga perlu dikelola dengan baik agar efek radiasi yang ditimbulkan tidak keluar di lingkungan. Penelitian ini akan dilakukan pemodelan panas peluruhan pada penyimpanan kering BBNB bentuk pebble dengan tipe storage tank yang telah digunakan pada reaktor HTR 10 menggunakan software ORIGEN-ARP. Dengan computational fluid dynamics (CFD) menggunakan Comsol Multiphysics maka pengaruh kecepatan udara pendingin dan ketebalan lapisan pengungkung terhadap profil suhu di setiap segmen storage dapat diketahui sehingga keselamatan penyimpanan BBNB pada aspek suhu dapat dianalisis. Dari hasil perhitungan dapat diketahui bahwa panas peluruhan yang dihasilkan oleh BBNB setelah keluar dari reaktor sebesar 620,2260 watt. Panas peluruhan tersebut semakin menurun seiring dengan lamanya waktu penyimpanan. Ketebalan beton tidak terlalu berpengaruh terhadap penurunan suhu di storage tank. Hal ini disebabkan oleh konduktivitas panas beton yang rendah sehingga laju perpindahan panas di setiap variasi ketebalan tidak berbeda secara signifikan. Ketebalan stainless steel berpengaruh terhadap gradien perubahan suhu pada storage tank. Semakin tipis stainless steel maka semakin banyak laju panas yang dialirkan dari grafit ke beton, sehingga suhu pada beton semakin besar. Semua hasil simulasi pada berbagai kondisi memenuhi syarat parameter suhu maksimum keselamatan.
ABSTRACT
Nuclear Fuel Waste is one of waste generated in operation of nuclear reactors. This waste is still producing fission products and heat of reaction that need to be managed properly so the effects of radiation emitted do not expose to environment. This research will be carried out modeling the decay heat in dry storage of pebble nuclear spent fuel with the type of storage tanks that have been used in the reactor HTR 10 using ORIGEN-ARP software. The effects of cooling air velocity and confinement layer thickness on temperature profile in every segment of storage can be determined with computational fluid dynamics (CFD) using Comsol Multiphysics so the safety of nuclear spent fuel storage on temperature aspects can be analyzed. Based on the calculation results can be seen that the decay heat generated by nuclear spent fuel after coming out from the reactor is 620.2260 watts. The decay heat decreases as the length of storage time. Concrete thickness does not significantly affect the declining temperature gradient in the storage tank. This is caused by the low thermal conductivity of concrete so the heat transfer rate in each variation of thickness is not different significantly. Stainless steel thickness affects the declining temperature gradient. Thinner the thickness of the stainless steel is used, greater the reduction of temperature gradient so equilibrium temperature of storage tank can be quickly achieved. All simulation results under various conditions compliy with the maximum temperature parameters of safety.;Nuclear Fuel Waste is one of waste generated in operation of nuclear reactors. This waste is still producing fission products and heat of reaction that need to be managed properly so the effects of radiation emitted do not expose to environment. This research will be carried out modeling the decay heat in dry storage of pebble nuclear spent fuel with the type of storage tanks that have been used in the reactor HTR 10 using ORIGEN-ARP software. The effects of cooling air velocity and confinement layer thickness on temperature profile in every segment of storage can be determined with computational fluid dynamics (CFD) using Comsol Multiphysics so the safety of nuclear spent fuel storage on temperature aspects can be analyzed. Based on the calculation results can be seen that the decay heat generated by nuclear spent fuel after coming out from the reactor is 620.2260 watts. The decay heat decreases as the length of storage time. Concrete thickness does not significantly affect the declining temperature gradient in the storage tank. This is caused by the low thermal conductivity of concrete so the heat transfer rate in each variation of thickness is not different significantly. Stainless steel thickness affects the declining temperature gradient. Thinner the thickness of the stainless steel is used, greater the reduction of temperature gradient so equilibrium temperature of storage tank can be quickly achieved. All simulation results under various conditions compliy with the maximum temperature parameters of safety., Nuclear Fuel Waste is one of waste generated in operation of nuclear reactors. This waste is still producing fission products and heat of reaction that need to be managed properly so the effects of radiation emitted do not expose to environment. This research will be carried out modeling the decay heat in dry storage of pebble nuclear spent fuel with the type of storage tanks that have been used in the reactor HTR 10 using ORIGEN-ARP software. The effects of cooling air velocity and confinement layer thickness on temperature profile in every segment of storage can be determined with computational fluid dynamics (CFD) using Comsol Multiphysics so the safety of nuclear spent fuel storage on temperature aspects can be analyzed. Based on the calculation results can be seen that the decay heat generated by nuclear spent fuel after coming out from the reactor is 620.2260 watts. The decay heat decreases as the length of storage time. Concrete thickness does not significantly affect the declining temperature gradient in the storage tank. This is caused by the low thermal conductivity of concrete so the heat transfer rate in each variation of thickness is not different significantly. Stainless steel thickness affects the declining temperature gradient. Thinner the thickness of the stainless steel is used, greater the reduction of temperature gradient so equilibrium temperature of storage tank can be quickly achieved. All simulation results under various conditions compliy with the maximum temperature parameters of safety.]"
2016
T45267
UI - Tesis Membership  Universitas Indonesia Library
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Muhammad Yunus
Pengembangan Heat Pipe Heat Exchanger (HPHE) pada Sistem Refrigerasi untuk Sistem Pendingin Kolam Penyimpanan Bahan Bakar Bekas Nuklir = Development of Heat Pipe Heat Exchanger (HPHE) in Refrigeration System for Spent Fuel Storage Pool Cooling System
"Pada teknologi penyimpanan basah, bahan bakar nuklir bekas disimpan di rak penyimpanan yang ditempatkan di dalam kolam air. Untuk mempertahankan temperatur air kolam agar berada pada batas kondisi operasi normal, panas yang dihasilkan akibat sisa peluruhan bahan bakar akan didinginkan oleh sistem pendingin. Pada penelitian ini akan dilakukan upaya penghematan energi pada sistem pendingin kolam bahan bakar bekas khususnya pada sistem chiller. Tujuan dari penelitian ini adalah mengembangkan desain Heat pipe Heat Exchanger (HPHE) pada sistem refrigerasi yang digunakan pada sistem pendingin loop sekunder. Dengan menggunakan sistem refrigerasi yang dilengkapi HPHE ini diharapkan dapat meningkatkan efektifitas dan penghematan penggunaan energi. Prototipe HPHE yang dikembangkan terdiri 5 buah heat pipe yang disusun sejajar dan dipasang diantara evaporator dan kompresor. Untuk melihat pengaruh HPHE terhadap performa sistem, maka dilakukan pengujian sistem refrigerasi dengan dan tanpa HPHE dan variasi beban kalor pada evaporator dengan variasi temperatur awal air 35 °C, 40 °C, 45 °C, 50 °C, dan 55 °C. Proses pengujian dilakukan selama 30 menit dengan daya penuh. Dari hasil pengujian diperoleh bahwa seiring dengan peningkatan variasi temperatur air, sistem refrigerasi mengalami penurunan kerja kompresor, peningkatan efek pendinginan, serta kenaikan coefficient of performance (COP). Penggunaan HPHE pada sistem refrigerasi terbukti mampu meningkatkan performa sistem dengan kerja kompresor yang semakin menurun, serta efek pendingin dan nilai COP yang semakin meningkat. Hasil optimal diperoleh pada variasi temperatur awal 55 °C dengan nilai kerja kompresor 48,1 kJ/kg, efek pendinginan 282,03 kJ/kg, dan COP 5,9. Resistansi termal HPHE semakin menurun seiring dengan kenaikan variasi temperatur air dengan nilai resitansi terbaik yaitu 0,37 °C/W. Dengan demikian, HPHE sangat potensial untuk diterapkan di sistem refrigerasi termasuk pada sistem pendingin kolam bahan bakar nuklir bekas demi meningkatkan efisiensi pendinginan dan menurunkan konsumsi listrik.
In wet storage technology, spent fuel is stored on storage racks placed within a water pool. To maintain the water pool temperature within the limits of normal operating conditions, the heat generated due to the residual decay of the spent fuel will be cooled by the cooling system. This study aims to implement energy-saving in the chiller system of the spent fuel pool cooling system, particularly focusing on the chiller system. The objective of this research is to develop a Heat Pipe Heat Exchanger (HPHE) design for the refrigeration system used in the secondary loop of the cooling system. By incorporating the HPHE in the refrigeration system, it is expected to enhance efficiency and energy conservation. The developed prototype of the HPHE consists of five parallelly arranged heat pipes installed between the evaporator and the compressor. To assess the impact of the HPHE on the system's performance, refrigeration system testing is conducted with and without the HPHE, considering variations in heat load on the evaporator with variation of initial water temperatures of 35 °C, 40 °C, 45 °C, 50 °C, and 55 °C. The testing process is carried out over 30 minutes at full power. Results from the testing indicate that with an increase in water temperature variations, The refrigeration system undergoes a reduction in compressor work, an enhancement in cooling efficiency, and an increase in the coefficient of performance (COP). The utilization of HPHE in the refrigeration system proves more effective in enhancing system performance, with a decreasing compressor work, an increasing cooling effect, and an elevated COP. The optimal results were obtained at an initial temperature variation of 55 °C, yielding a compressor work value of 48.1 kJ/kg, a cooling effect of 282.03 kJ/kg, and a COP of 5.9. The thermal resistance of the HPHE decreases with an increase in water temperature variation, with the best resistance value being 0.37 °C/W. Therefore, HPHE demonstrates significant potential for application in refrigeration systems, including those used in the cooling of spent fuel pools, to improve cooling efficiency and reduce electrical consumption."
Depok: Fakultas Teknik Universitas Indonesia, 2024
T-pdf
UI - Tesis Membership  Universitas Indonesia Library
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Titik Sundari
Pemodelan Dinamik dan Prediksi Kemampuan Sistem Kolam Penyimpanan Bahan Bakar Nuklir Bekas = Dynamic Modelling and Prediction of the Spent Nuclear Fuel Storage Pool System Ability
"Reaktor nuklir menghasilkan Bahan Bakar Nuklir Bekas (BBNB) yang umumnya disimpan di suatu kolam Instalasi Penyimpanan Sementara BBNB (IPSB3) dengan level air yang cukup untuk mendinginkan panas peluruhan dan meminimalkan paparan radiasi. Insiden Fukushima Daiichi unit 4 dimana tidak berfungsinya sistem pendingin menyebabkan akumulasi panas peluruhan yang menaikkan suhu dan laju penguapan air di luar kendali, memberikan pelajaran bahwa kolam-kolam ini termasuk IPSB3 dari Reaktor Serba Guna G.A. Siwabessy (RSG-GAS) memerlukan analisis kinerja termal yang memadai. Pemodelan dinamik IPSB3 diperlukan, dan penelitian ini bertujuan untuk mengetahui perilaku dinamik dan kapabilitas IPSB3 pada kondisi saat ini dan prediksi masa mendatang maupun station blackout (SBO). Pemodelan mengadopsi pendekatan campuran homogen dan memperhitungkan proses perpindahan panas di dalam badan air, udara ruangan, sistem ventilasi, udara ambien serta lingkungan tanah, menggunakan software Stella. Untuk prediksi di masa depan, diasumsikan 120 BBNB ditambahkan akhir tahun 2021 (Kasus 1) dan akumulasi BBNB dari 60 tahun operasi RSG-GAS (Kasus 2). Model dinamik ini divalidasi terhadap data eksperimen yang dilakukan di IPSB3 RSG-GAS. Prediksi model dinamik Stella memiliki kesesuaian dengan data eksperimen. Validasi pada kondisi operasi normal menunjukkan nilai mean relative deviation (MRD) dan mean squared error (MSE) secara berturutan yaitu 0,042% dan 0,0047 untuk prediksi temperatur, sementara untuk prediksi level secara berturutan adalah 0,01% dan 0,0008. Validasi pada kondisi SBO menunjukkan nilai MRD dan MSE sebesar 0,0254% dan 0,00178 untuk prediksi temperatur, sedangkan prediksi level air berturut-turut 0,00853% dan 0,0006. Pada kondisi operasi normal dengan mode operasi sistem VAC 8 jam dan HE sistem pendingin 6 jam setiap jam kerja, simulasi penambahan 120 BBNB menunjukkan bahwa temperatur air relatif dapat dipertahankan pada hari kerja, namun pada simulasi 60 tahun operasi akan terjadi kenaikan temperatur yang signifikan. Penambahan waktu operasi pendingin harus dilakukan untuk mencegah peningkatan suhu air secara terus-menerus. Jika terjadi SBO, air kolam dapat bertahan tanpa intervensi manusia secara berturut selama 142 hari pada inventori saat ini, 104,4 hari pada penambahan 120 BBNB, dan 45,8 hari pada inventori 60 tahun operasi RSG-GAS. Laju penguapan tertinggi terjadi ketika kondisi 300 jam SBO pada inventori 60 tahun operasi RSG-GAS, yaitu sebesar 0,12 kg/m2.jam, menunjukkan nilai dimana sistem produksi air bebas mineral masih mampu mengkompensasi kehilangan air akibat penguapan.
Nuclear reactors generate spent nuclear fuel (SNF) which is generally stored in an interim storage pool for spent fuel (ISSF/SFSP) with a sufficient water level to cool the decay heat and minimize the radiation exposure. The Fukushima Daiichi unit 4 incident in which the cooling system malfunctioned caused the accumulation of decay heat and raised the temperature and evaporation rate of water out of control, providing a lesson that these ponds include SFSP from the G.A. Siwabessy Multipurpose Reactor. (GAS-MPR) requires an adequate thermal performance analysis. SFSP dynamic modeling is required, and this study aims to determine the dynamic behavior and capabilities of SFSP in current conditions and future predictions as well as station blackout (SBO). The modeling adopts a well-mixture approach and takes into account the heat transfer process in water bodies, room air, ventilation systems, ambient air and ground environment, using Stella software. For future predictions, it is assumed that 120 SNF will be added by the end of 2021 (Case 1) and the accumulated SNF from 60 years of GAS-MPR operation (Case 2). This dynamic model was validated against experimental data conducted in the GAS-MPR SFSP. The predictions of the Stella dynamic model are in a good agreement with the experimental data. Validation under normal operating conditions shows the mean relative deviation (MRD) and mean squared error (MSE) values of 0.042% and 0.0047, respectively for temperature prediction, while the prediction levels are 0.01% and 0.0008, respectively. Validation on the SBO condition shows the MRD and MSE values ​​of 0.0254% and 0.00178 for temperature prediction, while the prediction of water levels is 0.00853% and 0.0006, respectively. In normal operating conditions with the VAC system operating mode 8 hours and HE cooling system 6 hours per working hour, the simulation of the addition of 120 SNF shows that the water temperature can be relatively maintained on working days, but in the 60-year simulation of operation there will be a significant increase in temperature. Increasing the cooling operating time must be done to prevent the continuous increasing in the water temperature. In case SBO occurs, pool water can survive without human intervention consecutively for 142 days in the current inventory, 104.4 days in the addition of 120 SNF, and 45.8 days in the 60-year inventory of GAS-MPR operation. The highest evaporation rate occurs when the condition of 300 hours SBO in the 60-year inventory of GAS-MPR operation, which is 0.12 kg/m2-hour, shows the value at which the demineralized water production system is still able to compensate for water loss due to evaporation."
Depok: Fakultas Teknik Universitas Indonesia, 2021
T-pdf
UI - Tesis Membership  Universitas Indonesia Library