PENENTUAN KEMURNIAN RADIONUKLIDA DARI PRODUK GENERATOR Mo-99/Tc-99m NON-FISI MENGGUNAKAN SPEKTROMETER GAMMA

Radionuklida medis teknesium-99m (Tc-99m) adalah jenis radionuklida yang paling banyak pemanfaatannya pada proses diagnostik  di dalam dunia kedokteran nuklir. Hal ini berkaitan dengan karakteristiknya yang memiliki masa paruh selama 6 jam dengan melepaskan energi gamma tunggal (Eγ) sebesar 140 keV. Tc-99m adalah produk dari generator Mo-99/Tc-99m dan merupakan anak luruh dari molibdenum-99  (Mo-99) yang memiliki masa paruh selama 66 jam. Radionuklida Mo-99 dapat diproduksi melalui reaksi aktivasi neutron yang membutuhkan target alam non fisi molibdenum trioksida (MoO3) sebagai target di reaktor nuklir, sehingga disebut generator Mo-99/Tc-99m non fisi. Tujuan penelitian ini yaitu dapat menentukan nilai kemurnian produk Tc-99m dari generator Mo-99/Tc-99m non fisi menggunakan metode spektrometer gamma. Hal ini dilakukan dengan menganalisis kalibrasi energi dan efisiensi pada spektrometer gamma dengan menggunakan sumber standar cair (Liquid Source) campuran Ba-133 dan Eu-152, dan sumber standar titik (Point Source) Eu-152, sesuai geometri masing-masing untuk pengukuran lolosan Mo-99 dan produk Tc-99m yang dihasilkan secara berurutan untuk setiap proses elusi tiga generator. Proses aktivasi neutron dari molibdenum alam (MoO3) dilakukan di reaktor nuklir G.A. Siwabessy, Indonesia. Kemurnian radionuklida produk Tc-99m dari generator Mo-99/Tc-99m non fisi diperoleh sebesar 99,999% untuk setiap elusi sedangkan lolosan Mo-99 terbesar yaitu 0,0018 dan terendah yaitu 1,04 x 10-4 µCi Mo-99/mCi Tc-99m. Hasil kelolosan Mo-99 yang diperoleh berada dibawah nilai 0,15 µCi Mo-99/mCi Tc-99m yang ditetapkan oleh US Pharmacopoeia, sehingga produk Tc-99m yang dihasilkan baik, dan menunjukan bahwa produk tersebut dapat digunakan untuk proses pelabelan menjadi radiofarmaka. Metode pengukuran kemurnian radionuklida ini dapat digunakan sebagai penentuan parameter kendali kualitas produk generator Mo-99/Tc-99m non fisi

ANALISIS PENGARUH GEOMETRI FUEL ASSEMBLY TERHADAP KRITIKALITAS DAN DISTRIBUSI FLUKS NEUTRON DALAM TERAS REAKTOR RSG-GAS MENGGUNAKAN OPENMC

Reaktor Serba Guna G. A. Siwabessy (RSG–GAS) termasuk ke dalam reaktor riset berjenis MTR memiliki elemen bakar berbentuk pelat lurus dengan berbahan bakar uranium silisida kerapatan 2,96 gU/cm3. Penelitian ini bertujuan untuk menganalisis pengaruh geometri elemen bakar model pelat lurus terhadap kritikalitas dan distribusi fluks neutron dalam teras reaktor RSG–GAS. Simulasi Monte Carlo dengan OpenMC dilakukan pada lima jenis elemen bakar, yaitu dari RSG–GAS, HANARO, WWR-SM, MARIA, dan BRR, dengan massa U235 250 gram per elemen bakar. Hasil penelitian menunjukkan bahwa bentuk geometri dari elemen bakar yang berbeda-beda mempengaruhi nilai kritikalitas dan distribusi fluks dalam satu teras yang sama. Nilai kritikalitas tertinggi didapatkan pada elemen bakar dari HANARO kemudian diikuti oleh RSG-GAS dan terendah didapatkan pada elemen bakar dari WWR-SM. Distribusi fluks pada elemen bakar dari MARIA dan BRR ini memiliki distribusi fluks yang lebih bagus

THE EFFECT OF THE DC-SPUTTERING PROCESS ON CHANGES IN THE HARDNESS VALUE AND ELEMENTS COMPOSITION OF BIOCOMPATIBLE STAINLESS STEEL 316L MATERIAL

Titanium Dioxide (TiO2) thin films have intriguing optical, photocatalytic, and electrical properties and have been investigated for various applications, including solar cells, biomaterials, corrosion-resistant materials, and gas sensor. In this study, TiO2 thin films were deposited on the surface of 316L Stainless Steel  to improve its mechanical properties as an implant material. The deposition method used was DC sputtering with variations in deposition times of 30, 60, 90, 120, and 150 minutes. Vickers hardness test and SEM-EDX characterization were carried out to determine the hardness value, elemental composition, and thickness of the TiO2 thin film formed. Based on these tests, it was discovered that the optimal hardness value of316L stainless Steel  material was attained at a deposition period of 90 minutes with a hardness value of 170.10 VHN, and the average thickness of the layer formed was ± 119.02 μm

Computational Fluid Dynamics Simulation of Temperature Distribution and Flow Characterization in a New Loop Heat Pipe Model

The loop heat pipe (LHP) is considered for passive cooling systems in nuclear installations. A combined approach of simulation and experimentation is essential for achieving comprehensive knowledge of the LHP. Research on the LHP using Computational Fluid Dynamics (CFD) is necessary to understand phenomena that are challenging to ascertain experimentally. This study investigates the temperature distribution and flow characterization in a new LHP model. The method used in this research is simulation using CFD Ansys fluent software. In the simulation, the LHP has an inner diameter of 0.1016 m. This LHP features a wick made from a collection of capillary pipes without a compensation chamber. Demineralized water is used as the working fluid with a filling ratio of 100% of evaporator volume. The hot water temperature in the evaporator section is set at 70°C, 80°C, and 90°C. The temperature on the outer surface of the condenser pipe is determined using experimental temperature inputs. An inclination angle of 5° and an initial pressure of 12,100 Pa was applied to LHP. The CFD simulation results show that the temperature distribution profile under steady-state conditions in the  loop heat pipe appears almost uniform. The temperature difference between the evaporator and condenser remains consistent. The flow of working fluid in the LHP is driven by buoyancy forces and fluid flow, allowing the working fluid in the LHP to flow in two phases from the evaporator to the condenser and then condensate from the condenser back to the evaporator. In conclusion, the temperature distribution and flow patterns in the LHP are consistent with common phenomena observed in heat pipes. This modeling can be used to determine the profiles of temperature distribution and flow in LHP of the same dimensions under various thermal conditions

Techno-Economic Assessment and Optimization of a Standalone System in Sebira Island, Indonesia

Nuclear power is known as a baseload generator in central power networks, but its implementation is too large-scale for microgrid applications. Nuclear power as a source of electricity is considered for microgrid applications due to its ability to produce emission-free energy. This research discusses the techno-economic analysis and optimization of a hybrid energy system design on Sebira Island, Indonesia, using a multi-year model in HOMER Pro software. Two scenarios were created: diesel-PV-battery and the second scenario, nuclear-PV-battery, with the baseline system being a diesel generator (DG) only. The research results show that with the optimal use of the nuclear-PV-battery system, the levelized cost of electricity (COE) is $0.128. This value is lower compared to the first scenario with a COE of$0.6577. The CO2 emissions generated in the optimal nuclear-PV-battery system are zero, making this system far more viable than other hybrid system schemes

MPS SIMULATION ON THE CORIUM MELT FLOW IN CASE OF REACTOR ACCIDENT

A simulation model has been made for molten corium in a nuclear reactor using the Moving Particle Semi-Implicit (MPS) method. By setting the value of dynamic viscosity and temperature of corium, simulations are carried out to display the pressure profile and flow velocity of the corium fluid that falls from the RPV to the plenum. In the first simulation to observe the pressure and velocity profile of the corium in the plenum, three conditions were made: the plenum was empty; the plenum was filled with corium fluid, and the plenum was filled with debris. The second simulation was carried out to determine the relationship between the time required for corium to reach the plenum for variations in corium viscosity and temperature values. The simulation results show that the increase in corium viscosity will be proportional to the length of time it takes to reach the plenum. In contrast to the effect of temperature where the increase in corium temperature will be the smaller the time required

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Analytical Method Validation of Thorium in Ore Sample Using UV-Vis Spectrophotometer

Monazite contains several rare earth elements (REE) along with radioactive elements, i.e., thorium (Th) and uranium (U). Thorium content in monazite is several times higher than uranium. Monazite contains around 12% thorium oxide, but the thorium content in this mineral varies depending on location. To determine the thorium content in monazite, an appropriate and validated analytical method is needed so that the reliability of the test results can be trusted. Apart from that, method validation is one of the clauses in SNI ISO/IEC 17025:2017 that must be fulfilled by the laboratory to be certified and produce reliable data. This research aims to validate analytical methods for non-standard and modified methods that are likely to be used outside the scope. In this research, the method used to digest and analyze thorium in mineral samples refers to the ASTM E2941-14 method with several modifications. Therefore, the analysis method needs to be validated. Validation of the analytical method is carried out by testing several parameters such as linearity and working range tests, accuracy, precision (repeatability), Limit of Detection (LOD), and Limit of Quantitation (LOQ). The results of linearity, accuracy, and repeatability tests that meet the acceptance requirements can be used as a method of validation evaluation. The results of the method validation parameter test met the acceptance requirements, with the linearity test showing a coefficient of determination (R2) of 0.997, the accuracy test showing % a recovery value of 106.22%, and the precision (repeatability) test showing %RSD of 3.76% with LOD value is 0.650 mg/L, and LOQ is 0.724 mg/L. Based on the results of these parameter tests, the method for analyzing thorium in mineral samples was validated

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Radioactive Mineral Distribution on Tin Placer Deposits of Southeast Asia Tin Belt Granite in Bangka Island

Bangka Island is an area rich in primary and secondary tin deposits. Tin deposits are formed around the contact between granite and older rocks, while secondary tin deposits are formed in the modern channels and paleochannels. Many previous researchers have researched radioactive minerals in primary tin deposits and modern channel deposits, but research on radioactive minerals in paleo channel deposits has never been carried out. The characterization of radioactive minerals in paleo channel deposits was done in this study to determine the potency of radioactive minerals in secondary tin deposits by comparing the content of radioactive minerals in paleochannels with modern channels and tin mine tailing deposits. The data used were mineralogical data and radioactivity data, along with the uranium and thorium content of the rocks from several previous studies. Data showed significant mineral content differences in paleo channel, modern channel, and tin mine tailings deposits. Mineral (monazite and zircon) content in tin mine tailing deposits was the highest. Source rocks for the radioactive minerals monazite and zircon are predicted to be the granitic rocks or tourmaline quartz veins of primary tin deposits. The radioactivity value of rocks in the paleo channel is relatively the same as the modern channel, ranging from 20 to 150 c/s. Uranium content in paleo channel is the same as modern channel deposits, ranging from 10 to 15 ppm eU. The thorium content of the rocks in the paleo channel ranges from 1 to 60 ppm eTh, while in the modern channel, it ranges from 1 to 45 ppm eTh. The radioactivity value and uranium content of the rocks are less effective for determining potential areas of radioactive minerals in placer tin deposits. In contrast, data on thorium content are quite effective for determining potential areas of radioactive minerals in placer tin deposits