Cover and Table of Content

Cover and Table of Content for Eksplorium Volume 44 No. 2 November 2023 Edition

ESTIMASI DOSIS 99mTc-PERTEHNETAT DARI GENERATOR 99Mo / 99mTc NON-FISI PADA ANAK-ANAK USIA 1-15 TAHUN UNTUK PROSEDUR DIAGNOSTIK

99mTc-pertehnetat berguna untuk pengobatan yang disertai dengan adanya info pemberian dosis ke tubuh manusia. Penelitian ini bertujuan untuk mengetahui estimasi dosis radiofarmaka 99mTc Pertehnetat pada anak-anak usia 1-15 tahun. Metode penelitian ini dilakukan dengan berbasis uji biodistribusi mencit dengan interval waktu 0,5, 1, 3, 5, 24 jam pasca injeksi radiofarmaka. Dari data hasil uji biodistribusi diperoleh %ID/gram organ mencit, dikonversikan ke %ID/gram organ manusia. Setelah itu, hasil perhitungan diinput ke software OLINDA/EXM dengan mengamati perbedaan dosis efektif untuk anak-anak usia 1-15 tahun. Berdasarkan nilai %ID/gram organ manusia masing-masing aktivitas uptake pada interval waktu pasca injeksi dari organ tertinggi dihasilkan yaitu, otot, hati, paru-paru, dan lambung. Hasil perbandingan dosis efektif OLINDA/EXM  menggunakan t hewan dan t manusia dapat diketahui hasil yang diperoleh menghasilkan nilai dosis efektif yang lebih kecil dibandingkan setelah dikonversi ke t manusia. Rata-rata dosis serap dari organ tertinggi pada OLINDA/EXM berada di tiroid, lambung, paru-paru dan. Hasil dosis efektif yang diperoleh untuk usia 1 tahun  1.11 x 10-2, 5 tahun 6.01 x 10-3 , 10 tahun 3.96 x 10-3 dan 15 tahun 2.50 x 10-3 . Oleh sebab itu, besar dosis efektif yang dihasilkan semakin besar terhadap umur pasien yang lebih muda

Experimental Investigation of Natural Circulation Stability Phenomena in a New Loop Heat Pipe Model

The severe accident at the Fukushima Dai-ichi Nuclear Power Plant in Japan in 2011 highlighted the critical need for a passive cooling system to dissipate residual decay heat following the failure of active cooling systems in the nuclear facility. The loop heat pipe (LHP) is a promising technology for such applications. The objective of this research is to understand the natural circulation stability phenomena of new LHP model under varying conditions of filling ratio and heat load. The experimental methodology employed a laboratory-scale LHP model made of copper with an inner diameter of 0.104 m. The experiments were designed with filling ratios of 20%, 40%, 60%, 80%, and 100%, and hot water temperature as the evaporator heat source with variations of 60°C, 70°C, 80°C, and 90°C. The initial operating pressure was 10665.6 Pa, with a 5˚ inclination angle, demineralized water as the working fluid, and cooled by air at a velocity of 2.5 m/s. The results show that the natural circulation within the LHP occurs in two phases and maintained stability, with optimal performance observed at an 80% filling ratio and 90°C. The conclusion of this research indicates that natural circulation stability in the LHP operates well and occurs in two phases, proving that natural circulation in the LHP is effective in heat dissipation

Analysis of the Reactivity Coefficient of the PWR Thorium Fuel

In design, control, and safety—especially in PWR reactors—the Reactivity Coefficient parameter is crucial. The validation of every new library for an accurate parameter prediction is then crucial. The purpose of this work is to determine the value of the reactivity coefficient at BOC and EOC using the WIMDS code based on ENDF/B-VIII.0 nuclear data files. The PWR-1175 MWe experiment critical reactors, which use Th-UO2 (thorium) fuel pellets, are a set of light water-moderated lattice experiments that are used for this purpose. The study is applied to the new cross-section libraries for WIMSD-5B and WIMSD-5B with ENDF/B-VIII.0 lattice code. The results showed that the fuel temperature reactivity coefficients for the PWR reactor at BOC and EOC using new libraries are – 4.07 pcm/K and – 2.72 pcm/K, respectively. Moderator Temperature Reactivity Coefficient at BOC and EOC are -1.8E-03 pcm/K and 3.73 pcm/K, respectively. Compared to the experimental data of the reactor core, the difference is in the range of 5.0 %. It can be concluded that for the PWR using thorium fuel as a model, all reactivity coefficients are negative and it is a good design for the safety of operation

HAZOP-Based Radiological Risk Assessment of Pebble Bed Fuel Handling Systems

The High-Temperature Gas-Cooled Reactor (HTGR), a promising candidate for Generation IV nuclear reactors, boasts superior inherent passive safety features and a continuous fuel handling system. This system employs multi-pass cycles, utilizing pneumatic and gravitational mechanisms to feed, circulate, and unload the pebble bed fuel element. This paper presents a descriptive analysis assessing the safety risk of the fuel handling system design in HTR-10. The Hazard and Operability Study (HAZOP) methodology is employed to identify hazard parameters, deviation limitations, causes, impacts, and potential risks to the system’s main components. The establishment of probability scales, consequence criteria, risk level ratings, and control activities adheres to the ISO 31000 standard. Primary data were gathered through expert interviews, while secondary data were sourced from design layout documentation, literature reviews, and safety analysis reports. Six main components - the elevator, core, singulator, failed fuel separator, burnup measurement, and distributor - were selected as assessment nodes from the piping and instrumentation diagram. The assessment revealed that each node initially presented a moderate to extreme risk potential (risk level rating C to E). However, after applying the effectiveness index of the designed control, the residual risk for all nodes was reduced to an acceptable limit (risk rating A - very low). Therefore, the fuel handling system design already incorporates adequate control activities to mitigate potential safety risks due to system component failure. As safety risk assessment is dynamic, it should be reviewed periodically or whenever there are design changes at any project stage. This ensures the safety risk magnitude is consistently known and managed effectively

Acknowledgement

Abstract CollectionKeywords IndexAcknowledmen

Evaluation of Pixelated Plastic Scintillators Coupled to Multi-Channel Silicon Photomultipliers for Beta-Ray Detection and Source Localization

This paper presents a novel detector design for radiation detection technology, based on pixelated plastic scintillators coupled to multi-channel silicon photomultipliers (SiPMs). This detector combines the efficiency of plastic scintillators with the sensitivity and versatility of SiPMs, Overcoming the limitations of traditional photomultiplier tubes in terms of durability, power consumption, and sensitivity. The compact and modular nature of the detector makes it suitable for diverse environments and applications, such as portable radiation monitoring devices or integration into existing experimental setups. The performance of the detector was evaluated using beta-ray sources of 36Cl and 90Sr, and it was demonstrated that the detector can detect and localize the point source with high accuracy and resolution

CESIUM CHEMISORPTION ONTO STAINLESS STEEL UNDER SIMULATED LIGHT WATER REACTOR SEVERE ACCIDENT

During light water reactor severe accident, source terms may interact with structural materials, generating new compounds and affecting their volatility which make the existing codes could not accurately estimate the radioactive release. Cesium is one of the source terms that can interact with structural materials and contributes greatly to the late release phenomenon. Several studies have been conducted to predict the physicochemical interactions between cesium and structural materials. However, the types of chemisorbed cesium compounds onto structural materials are still under discussion. For this reason, this study was carried out using advanced techniques, involving TEM, SEM, EDS and FIB to estimate the chemisorbed cesium compounds onto stainless steel structural material under simulated light water severe accident. This study indicates that cesium is strongly adsorbed on the oxide layer of stainless steel in the form of cesium silica, cesium aluminum silica, and/or cesium ferro silica. CsFeSiO4 and CsAlSiO4 could dominate these compounds

Geological Structure Identification Using GGMplus Satellite Gravity Data in The Area Surrounding Mount Tampomas

Satellite gravity provides a new alternative in geological exploration with several advantages, such as low operational cost and large covering area. GGMplus satellite gravity data provide better accuracy for several applications such as lithology or fault identification. Satellite gravity provides a new alternative in geological exploration with several advantages, such as lower costs, broader area coverage, and easily accessible data. Mount Tampomas is one of the areas that has geothermal prospects and a mountain area that has many types of rock formations and faults. This research has been conducted using GGMplus satellite gravity data in the Mount Tampomas area to obtain the second vertical derivative (SVD) and identify the fault distribution in the area. The GGMplus Gravity Acceleration data was corrected and filtered to obtain SVD structures in the area. The structure in this area is dominantly trending northwest-southeast and west-east. The area around Mount Tampomas forms a structure in the form of a caldera. In addition, there are also structures trending north-south at coordinates 81500-82000 E. Some of these structures were overlaid with a geological map to see the suitability of the processed data with the geological conditions that have been studied. The comparison is done by overlaying the structure of the interpretation results and the contour of the value 0 from the Second Vertical Derivative (SVD) data so that we get four fault structures that correlate with the geological map, three calderas, and one lineament that correlates with the lineament map

AN IMPROVEMENT OF ARJUNA 1.0 CONVEYOR SYSTEM FOR 3D IRRADIATION

An improved design of the conveyor system of Arjuna 1.0 electron accelerator for 3D object irradiation has been done. The penetration of low energy electrons is less than 1 cm in the surface, causing a challenge for the irradiation process for sterilization of 3D objects. We design a conveyor that can be rotated 360o to irradiate objects evenly. The dimension of this conveyor is 1750 x 600 x 800 mm and the maximum diameter of the object is 7 cm. Based on the Frame Bending Stress analysis to calculate the strength of the conveyor frame, it is shown that the maximum displacement is only 0.029 mm, which is very small so it will cause no disturbance to power transfer from the motor to the conveyor. The normal stress (Smax) is 3.926 MPa and the bending stress for Smax (Mx) and Smax (My), are 2.391 MPa and 3.925 MPa respectively. We also calculate the stress analysis of the 3 mm-thickness of the motor mount and found that the Von-Misses Stress, first, and third Principal Stress are 4.425 MPa, 5.01 MPa, and 1.95 MPa respectively. These results confirm that the design and the material used for the conveyor are safe because the stress is very low than the material’s yield strength which is 207 MPa. The power needed for this conveyor is 0.01724 kW, with a maximum speed is 880 rpm. The new model of 3D conveyor has been constructed and can be implemented to ARJUNA 1.0 to irradiate objects on all its surface