Atom Indonesia (E-Journal)
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Calculation of Control Rods Reactivity Worth of RSG-GAS First Core Using Deterministic and Monte Carlo Methods
Get PDFThe control rod worth is a key parameter for the research reactor operation and utilization. Control rod worth computation is a challenge for the fully-deterministic and Monte Carlo calculations, including the few-group cross section generation, and the core analysis. The safe and reliable utilization of research reactor demands the possible accurate information of control rod worth because they are used to compensate the excess reactivity for safe reactor operation and its controlled shut down. The criticality positions of the control rods change with time due to buildup of fission products during the reactor operation. It is therefore important to determine the reactivity worth of control rods. The aim of this article is to obtain reliable control rod worth of the first core of RSG-GAS as a verification and validation result. For this purpose, deterministic and Monte Carlo models of the reactor core were developed and confirmed by the experimental results of excess reactivity, shutdown margin, and combined control rod reactivity worth using the combination of WIMSD-5B and Batan-3DIFF computer codes. WIMSD-5B is a neutron transport theory-based lattice cell modeling code that is used for the generation of group constants for different regions of the reactor core. These are provided as input to the diffusion theory based Batan-3DIFF code which performs the global core calculations for the reactor system. For the Monte Carlo model, to estimate the reactivity worth of control rods, the MCNP6 code is used. The result of this analysis showed that for the integral control rod worth a good agreement was found between experimental data and Monte Carlo simulation results but up to 5 % difference occurred between experimental results and diffusion result
Atmospheric Dispersion Analysis for Expected Radiation Dose due to Normal Operation of RSG-GAS and RDE Reactors
Get PDFBATAN is planning to build an experimental power reactor, the RDE, to complement the RSG-GAS reactor that is already operating in the Serpong Nuclear Zone (KNS). The experimental power reactor is an HTGR (high-temperature gas-cooled reactor) with 10 MWt power, while the RSG-GAS is a pool-type water-cooled reactor with 30 MWt power. According to standard regulatory practices, under normal operating conditions of the plant, radiological assessment of atmospheric releases to the environment and assessment of public exposures are considered essential. The purpose of this study is to estimate the dose acceptance in Serpong Nuclear Zone (KNS) after operate the RDE operates in KNS-2. To assess the doses, the PC-CREAM 08 computer code was used. It uses a standard Gaussian plume dispersion model and composes a suite of models and data for estimation of the radiological impact assessments of routine and continual discharges from a nuclear reactor. The input data include sourceterm from the RDE and the RSG-GAS, a stack the height of 60 m annual radionuclides release, meteorological data from the Serpong local meteorological station, and agricultural products data from Serpong site. Results show that the highest individual dose in the area around KNS for adults is 6.16×10-3 mSv/y in the S (South) direction and 300 m distance from the stack of RSG. The highest collective dose around KNS within 3 km radius is 6.37×10-3 man-Sv/yr. The results show that the radiological impact of the KNS on the critical groups of public and the individual effective doses satisfy the limits given by the Nuclear Regulatory Agency of Indonesia (BAPETEN). The operation of RDE in KNS-2 does not add significantly to acceptance radiation dose in the environment in KNS. It can also be concluded that the estimated effective doses are lower than the dose constraint of 0.3 mSv/y associated with this plant
High Temperature Oxidation Behavior of Fe-Cr Steel in Air at 1000-1200 K
Get PDFThe high temperature oxidation behavior of Fe-Cr steel was studied in air at elevated temperatures of 1000, 1100 and 1200 K for up to 72 ks. The mass change of all samples was recorded in order to evaluate their oxidation kinetic. The structure of oxide scales was investigated by mean of X-ray diffraction and SEM-EDX. According to oxidation kinetic curve, the mass gain of oxidized sample increases with increasing oxidation time and temperature. At 1000 and 1100 K, the Fe-Cr steel exhibits an excellent oxidation resistance. As oxidation temperature increase to 1200 K, however, the accelerated oxidation occurred. This is considered due to breakaway oxidation. The Fe-Cr steel forms a duplex oxide layer consisting of Fe-rich oxides in the outer layer and Fe-Cr oxides in the inner layer. The obtained results suggest that the oxidation temperature strongly affects the oxidation resistance of Fe-Cr steel and the structure of formed oxide layer on the steel surface. The influence of oxidation temperature on the oxidation resistance and scale structure is discussed in this paper
Micronucleus Frequencies and DNA Repair Gene XRCC3 Polymorphism in Radiation Workers of Center for Multipurpose Reactor
Get PDFThe carcinogenic effects of low radiation doses have not been fully understood until now. Studies on individuals that are occupationally exposed to low radiation doses can help to address this question. This study assesses the micronucleus (MN) frequencies as indicator of DNA damage in radiation workers that are occupationally exposed to low radiation dose. The influence of single nucleotide polymorphisms (SNPs) in XRCC3 gene on the frequency of micronuclei was also evaluated in this study. The effects of confounding factors of gender, age, and smoking status on MN frequencies was assessed in all samples. A total of 60 subjects consisting of 30 radiation workers from Center of Multipurpose Reactor (CMPR), National Nuclear Energy Agency (NNEA) of Indonesia, and 30 control samples were enrolled in this study. The results showed that the difference between MN frequency in radiation workers and in control samples was not statistically significant [0.019 vs. 0.021; p = 0.549]. Age and smoking status did not affect micronucleus frequencies in all samples (p = 0.723 and 0.828). Micronucleus frequencies in females were higher compared to males, even though the difference was not significant (p = 0.3). Radiation workers with variant alleles for XRCC3 olymorphism did not showed higher MN frequencies compared to the controls with the same genotypes. The small numbers of samples with XRCC3 variant alleles found in this study possibly contributed to the insignificant difference of MN frequencies between wild-type allele (Thr/Thr) and mutant alleles (Thr/Met or Met/Met). Further investigations using larger sample sizes and MN assay in combination with human pan-centromeric probe should be conducted to validate this study results. Other SNP in XRCC3 gene also should be evaluated to find out the association between SNP and MN frequencies
Dynamic Analysis on the Safety Criteria of the Conceptual Core Design in MTR-type Research Reactor
Get PDFOne of thehigh-priority research activities in BATAN is designing a new MTR-type research reactor with a new fuel. The core follows a compact core model that consists of 16 fuels and 4 control rods. The increasing heat flux at the fuel will cause the temperature of the fuel and cladding to increase so that the coolant flow rate needs tobe increased. However, the coolant flow rate in the fuel element is limited by the thermal-hydraulic stability in the core. Therefore, dynamic analysis is important in evaluating the design and operation of nuclear reactor safety. The objective of this research work is to carry out a dynamic analysis for a conceptual MTR research reactor core fuelled with the low-enrichment U9Mo-Al dispersion. The calculations were performed using WIMSD-5B, Batan-2DIFF, Batan-3DIFF, POKDYN, and MTRDYN codes. Steady-state thermal-hydraulic parameters and dynamic analysis were determined using the MTRDYN code. The calculation results show that the maximum temperatures of the coolant, cladding, and fuel meat with the uranium density of 3.96 g cm-3 are 76.01 °C, 192.02 °C, and 196.24 °C, respectively. The maximum value of fuel meat temperature for safety limit is 210 °C, which means that the maximum temperatures fulfill the design limit, and therefore the reactor operates safely at the nominal power. The dynamic analysis shows that inherent safety can protect the reactor operation when insertion of reactivity occurs in the core
Study of Cellulose-N,N'-Methylenebisacrylamide-Acrylic Acid as Pb2+ Ion Adsorbent
Get PDFCellulose can be used as a metal ion adsorbent. However, it is specific to certain metal ions and has some drawbacks. To increase the capture of certain metal ions,cellulose needs to be modified. Cellulose modification was carried out using N, N'- methylenebisacrylamide (MBA) as crosslinking agent and acrylic acid (AA) as grafting agent. Gamma rays from Cobalt-60 was used as the initiator by simultaneous irradiation method. The aim of this study is to improve and observe the capture ability of cellulose as Pb2+metal ion adsorbent. The characterization was performed by FTIR, DSC, SEM, and EDX. The thermal analysis and ion exchange capacity measurement showed that the resulting copolymer has a better thermal stability and ion exchange ability thanpure cellulose.The applications of the copolymer on Pb2+ ion adsorption indicated that the maximum adsorption is 99.8 % of 3 ppm Pb2+ ion sorbent at pH ≈ 7. SEM analysis showed that the copolymer is porous while pure cellulose appears fibrous. EDX Analysis showed Pb2+ metal ion adsorption by cellulose-MBA-AA
The Enhancement of Uranium and Thorium in Bangka Tin Slag
Get PDFSeveral researches have informed that air pollution, by-products, and residues in and waste products of natural resources exploitation and consumer goods contain uranium and thorium. In this research, the enhancement of these two metals resulted from the extraction process of Bangka tin slag. To deal with the enhancement of uranium and thorium, Bangka Tin Slag (BTS) was dissolved in Fluoric acid (HF), Chloric acid (HCl), and Sodium Hydroxide (NaOH). The result shows that Bangka tin slag has high contents of uranium, 3,404 ppm, and thorium, 25,850, which were achieved through the dissolution of BTS-roasting-quenching-sieving (BTS-RQS) residues in HF 8%, HCl 6M, and NaOH 10M