One of the major component in neutron radiography is a collimator that is used to collimate the neutron in parallel beam with less gamma ray contamination and high thermal neutron flux. The collimator consists of seven components and the interest component is an aperture as it is used to prevent the thermal neutron from entering the beam except through the center hole. In this study, the collimator design was taken from radial beam port at NR facilities at ANM with the collimation ratio is 46.4. In order to increase the collimation ratio, optimization of the aperture component has been done on four different material and 1-5 cm diameter parameters. The optimization of apertures shows that the cadmium with 1 cm diameter yields the thermal neutron flux at the collimator inlet and outlet with 1.78 x103 n cm-2 s-1 and 5.90 x102 n cm-2 s-1 while the gamma ray contamination was 10.7 μSv hr-1. The optimization succeed to produce high L/D ratio however the thermal flux was low and the gamma contamination was higher that original design but satisfied the ICRP 74 condition for radiation worker.
In order to prepare Malaysia to be nuclear ready, the Malaysian 1 MW TRIGA MARK II research
reactor (RTP) located at the Malaysian Nuclear Agency was premeditated with the aim to effectually
actualize the multitude areas of basic nuclear research, labor training and education. To meet the
modern safety standards, analyses of a strong interaction between the thermal-hydraulic system
behavior and the space-dependent neutron kinetics are needed as mere thermal-hydraulics codes are
said to be incapable to succeed the present safety standards. This could be achieved through the
coupling of neutronic and thermal-hydraulic codes of the reactor. Previous studies had shown that the
coupled codes are able to successfully be employed for the correlation between thermal-hydraulic
analysis and neutron kinetics at transient and steady state. In this study, the coupling was achieved
through MCNP and TRIGLAV codes for neutronic and thermal-hydraulic respectively. Core-15 of
RTP was modeled for both of the codes; hence calculating the criticality, analysis of power and
neutron flux distribution. The consistency and accuracy of the developed Core-15 MCNP model was
established by comparing calculations to the experimental results and TRIGLAV code. The criticality
predictions for both codes are in very good agreement with the experimental results. The core reached
its criticality after 66 fuels. The highest hot rod power peaking factor was found to be 1.28. The
results are conservative and can be applied to show the reliability of MCNP and TRIGLAV codes.
Nuclear technology has found a great need for use in medicine, industry, and research. Smoke
detectors in our homes, medical treatments and new varieties of plants by irradiating its seeds are just a few examples of the benefits of nuclear technology. Portable neutron source such as Californium-252, available at Industrial Technology Division (BTI/PAT), Malaysian Nuclear Agency, has a 2.645 year half-life. However, 252 Cf is known to emit gamma radiation from the source. Thus, this chamber aims to provide a proper gamma shielding for samples to distinguish the use of mixed neutron with gamma-rays or pure neutron radiation. The chamber is compatible to be used with other portable neutron sources such as 241 Am-Be as well as the reactor TRIGA PUSPATI for higher neutron dose. This chamber was designed through a collaborative effort of Kulliyyah Engineering, IIUM with the Bahagian Teknologi Industri (BTI) team, Agency Nuklear Malaysia.
The interference of 235 U on 226 Ra concentration measured directly using the γ-ray energy of 186 keV and the interference of 228 Ac on the 40 K analysis by gamma-spectrometry system were highlighted and discussed. The interference of 235 U was demonstrated to be very significant, i.e. 45% of the 226 Ra concentration measured directly at 186 keV in natural samples containing uranium series in equilibrium. The interference of 228 Ac on 40 K concentration was particularly significant for samples containing high concentration of 228 Ac ( 228 Ra) such as radioactive minerals. Another important aspect discussed is the assignment of the right emission probability of the 583 keV and 2614 keV of the 208 Tl for the purpose of estimating the concentration of 232 Th or other radionuclides in the thorium series. Extra cautions are required in the interpretation of the measured 208 Tl concentration in samples of various natures. It is suggested that the emission probability used for 208 Tl be reported for comparison and verification.
A study to measure the concentrations of long-lived radionuclides of the uranium and thorium series in naturally occurring radioactive materials (NORM) wastes was carried out using gamma spectrometry and neutron activation analysis methods. It was found that radionuclides in the NORM wastes of the oil/gas production and ores/minerals processing industries were not in equilibrium. The 226 Ra/ 238 U and 228 Ra/ 232 Th ratios were between 0.001 and 2220 indicating that the concentrations of daughters radionuclides ( 226 Ra, 228 Ra) were very low or very high compared to the parent radionuclides ( 238 U, 232 Th) in the NORM wastes.
The measurements of absorbed dose rate in air around amang plant buildings were carried out using a scintillation detector. It was found that the mean radiation levels at seven amang plants were in the range of 1.6 – 5.5 µGy h -1. The individual maximum value measured was 56 µGy h -1. The annual dose to a worker transporting the minerals to the plant was estimated to be 1.5 mSv y -1.
Thirteen solid waste samples labeled as scales were collected from a storage area of a crude oil production industry and were analysed for radionuclides concentrations. The radium-226 and radium- 228 concentrations were found to be unexpectedly low, i.e. less than 20 Bqkg. However, six samples were found to contain 7 to 2240 Bq/kg 60 Co. Thus, besides naturally occurring radionuclides, there is a possibility to find artificial radionuclides in solid wastes from crude oil production industry.
The effect of sample density in the determination of radionuclides by gamma spectrometry was studied using two multinuclide standard sources of different densities. The self absorption corrections due to differences in sample matrix densities were estimated. The corrections were used in the analysis food and soil samples having packing densities between 0.2 – 1.6g/ml.
Neutrino is one of the nuclear particles that are necessary for the correct description of nuclear beta decay. The standard idea is that it is a massless neutral particle and its existence was postulated in order to save the conservation of ener gy principle. This particle was later detected experimentally and it is now known that neutrino has mass. The problem of astrophysical neutrino detection has produced a new phenomenon of neutrino oscillation where the three neutrino flav ours can oscillate between themselves. This paper studies the two component neutrino oscillation problem. We study the neutrino oscillation by using the Lagrangian formulation. In our study, we assume that the neutrinos are produced as n eutrino mass eigenstate and propagate in the vacuum in the superposition of two neutrino flavour state. The Lagrangian for neutrinos with their mass and the oscillation terms were obtained. By using the mass matrix in the Lagrangian, we formulate the time evolution operator in the interaction picture. The neutrino oscillation probability obtained by using the Lagrangian formulation have the same result with the one obtained by using quantum mechanics formulation. This study hopes to gain some deeper understanding into the behaviour of neutrino beyond the Standard Model.
In this study, the numerical simulation in a mixing vessel agitated by a six bladed Rushton turbine has
been carried out to investigate the effects of effective parameters to the mixing process. The study is intended to screen the potential parameters which affect the optimization process and to provide the detail insights into the process. Three-dimensional and steady-state flow has been performed using the fully predictive Multiple Reference Frame (MRF) technique for the impeller and tank geometry. Process optimization is always used to ensure the optimum conditions are fulfilled to attain industries’ satisfaction or needs (ie; increase profit, low cost, yields, etc). In this study, the range of recommended speed to accelerate optimization is 100, 150 and 200rpm respectively and the range of recommended clearance is 50, 75 and 100mm respectively for dual Rushton impeller. Thus, the computer fluid dynamics (CFD) was introduced in order to screen the suitable parameters efficiently and to accelerate optimization. In this study,
Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 µm with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nanosheets.
Mechanical activation of quartz was carried out in jet mill at various specific kinetic energy level and classifier speed. The characterization of the particle size, crystallite size, amorphism rate and lattice strain was conducted on the feed and mechanically activated particles. The area under the prominent quartz peak was used to calculate the amorphism rate of the mechanically activated particles. Scherer equation was used to determine the crystallite size of the feed and mechanically activated particles. Mean particle size less than 5μm was obtained when the specific kinetic energy is ranging between 500 kWh/ton and 1000 kWh/ton. Amorphism of the mechanically activated particles up to 18% was observed at 500 kWh/ton. The crystallite size and lattice strain is influence by the intensity of the specific kinetic energy and classifier speed. The reduction in the crystallite size up to 39% was observed where the minimum crystallite is 23nm. The lattice strain is ranging from 0.024 to 0.038 respective to the specific kinetic energy and classifier speed.
Tetragonal Y2O3 stabilized Zirconia (t-Y-ZrO2) powders were doped with Nb2O5 to seek a possibility if electronics doping would enhance the electronics conductivity of the insulating oxide. In this work Y2O3 was added as a stabilizer to produce tetragonal ZrO2 whereas Nb2O5 was added for the electronic doping. Several compositions of powders were prepared by thermal decomposition method and were post annealed at different temperatures. Precursor solutions were prepared from the mixture of zirconyl nitrate, yttrium nitrate and niobium tartarate as well as TEA (triethanolamine). The mixed solution were evaporated, pyrolysed and calcined to produce nanosized powders. The phase formation of the as-made powders was investigated by x-ray diffractometer. The additions of 7% Y2O3 were found to stabilize the tetragonal phase of zirconia.
The addition of Nb2O5 did not alter the stability of the tetragonal phase but it was found that the conductivity of the material has changed. The band gap as measured by the UV-Visible Spectrometer gave a value in the range of 2.97 to 5.01 eV. XRD was also used to deduce the crystallite size (by using Scherer’s equation) and transmission electron microcopy was used to view the particle sizes and shapes. The Nb doped t-Y-ZrO2 prepared in this work was to be nanosized crystal with size ranges from 7 nm to 15 nm.
The objective of this study was to compare the acquired image of teflon, human bone equivalent material on a Positron Emission Tomography/Computed Tomography (PET/CT) scanner with Monte Carlo simulation (MCNP). The cylindrical shape teflon phantom with dimensions of 19.5 cm length and 5.0 cm diameter was used for imaging with different settings of kilovolts (kV) and milliamperes (mA) of PET/CT. In this simulation, the photon flux in each pixel was accumulated by the Flux Image Radiograph (FIR) tally as flux image detectors and the image was plotted using Microsoft Office Excel. Results show that MCNP image was comparable with that of CT image and the obtained MCNP image depends on pixels size of the FIR tally.
Self-propagating high-temperature synthesis (SHS) of powder compacts is a novel processing technique being developed as a route for the production of engineering ceramics and other advanced materials. The process, which is also referred to as combustion synthesis, provides energy- and cost-saving advantages over the more conventional processing routes for these materials. In the case of titanium or titanium alloy materials, prior researches employed powder metallurgy technology for preparing metal matrix composites, MMCs and laminated structures through the use of fine powders of an inert phase or phases (TiC, TiN, TiB and TiB2B ) dispersed in Ti or Ti alloy powders. The present research relates to manufacture of titanium-ceramic composites that are synthesized by combustion synthesis (SHS) and retains a multilayered composite microstructure comprising one or more titanium-based layers and one ceramic titanium carbide layers.
There is a growing interest from, newcomer countries to utilise nuclear energy for electricity
generation. The International Atomic. Energy Agency (IAEA) has developed two methodologies,
namely, the IAEA Milestone Approach and the International Project on Innovative Nuclear Reactors
and Fuel Cycles (INPRO) Methodology to help its Member States in assessing the viability of nuclear
power programme (NPP) and nuclear energy system. This paper highlights important features of both
methodologies in supporting deployment of nuclear power programme for a newcomer country. In
summary, the IAEA Milestone Approach focuses for near term while the INPRO Methodology focuses
for long term assessment to support the deployment of first NPP in newcomer countries. Depending
on newcomer country's priority and resources, both methodologies can be performed either separately
or in-parallel.
We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
The preformation factor of alpha-decay process in compound nuclei is microscopically proposed with a new perspective. The formation of alpha particle inside the parent nuclei is considered as a quantum-mechanical state which is yielded from a certain interaction among the valance nucleons. This interaction is very similar to that one responsible for the formation of the quasi-bound states in many-body system. This introduced microscopic perspective might give more insight to the understanding of the nuclear structure in the compound nuclei.
Feasibility studies on the vitrification of spent ion exchange resins combined with glass cullet powder have been conducted using a High Temperature Test Furnace. Bottle glass cullet powder was used as matrix material to convert the ash of the spent resins into a glass. Vitrificat ion of spent ion exchange resins presents a reasonable disposal alternative, because of its inherent organic destruction capabilities, the volume reduction levels obtainable, and the durable product that it yields. In this study, the spent ion exchange resin from the PUSPATI TRIGA reactor of Nuclear Malaysia was combusted in a lab scale combustor and the resulting ash was vitrified together with glass cullet powder in a high temperature furnace to produce a stable spent resin ash embedded in glass. The factors affecting this immobilized waste, such as thermal stability, radiological stability and leachability have all been investigated. However, the outcome of these tests, which include the radionuclide activity concentration in the slag, the optimum conditioning temperature - in relation with volume reduction during vitrification - and the volume mixing ratio of matrix material were reported. It was found that the radionuclides present in spent resins were 54 Mn, 60 Co and 152Eu. The elementary chemical composition (carbon, hydrogen, nitrogen and sulphur) of spent resins was 27.6% C, 5.68% H, 2.04% N and 4.20% S, respectively. The maximum calorific value of spent resins was 1735 kJ/kg. The average activity concentrations of 54 Mn and 60Co in ash at 200oC were 9,411 ± 243 Bq/Kg and 12,637± 201 Bq/Kg. flue gases containing CO2, CO, SO2 and NO started to be emitted above 200oC. The optimum conditioning temperature was also the highest tested, i.e. 900oC in 45 minutes, and the best mixing ratio ash to matrix material was also the highest, ie 1:9. Finally, the leaching analysis of slag at 900oC in 45 minutes showed that the leaching activity of 60Co was below 0.5 Bq/mL.
The Lembah Bujang archeological complex near Sungai Petani, Kedah consists of various structures constructed at different times and spread over a wide area. This paper reports on the thermoluminescence (TL) dating of one of these structures. The structure was found to be 350 ± 90 yrs old. This is very young as compared with other structures that are from the 4th to the 16th centuries. This structure is suspected to be remnant of a Muslim Mosque whereas the other structures were Hindu and Buddist temples.