Sedimentation rate at Setiu lagoon using natural radiotracer 210Pb technique

This study was conducted to determine the sedimentation rate of soil at Setiu Lagoon by using natural radiotracer 210Pb. The area covers a 10 km length lagoon involving 5 sampling stations of approximately 2 km apart. The sediment samples were collected using a corer box comprising of a meter long transparent PVC plastic pipe inserted manually into the sediment bed 2 m below the water surface. The sediment core extracted were then cut into several 5 cm interval, labeled and stored in a close beaker. A total of 24 samples were collected from the 5 sampling stations. The measurement of 210Pb activity was made using Hyper Purity Germanium (HPGe). The total activity of 210Pb was measured from gamma ray peak of energy 46.5 keV and supported 210Pb by the weighted average decay of 226Ra daughters at 295, 351 and 609 keV. Unsupported 210Pb was calculated as the difference between the total and the supported 210Pb activity. Two models were used in this study to calculate the sedimentation rate; the Constant Initial Concentration (CIC) and Advection-Diffusion Equation (ADE) model. The results show that, there are differences in sedimentation rate values of each model for each station. The sedimentation rates obtained using CIC model varies from 0.08 to 0.37 cm/yr whereas ADE model varies from 0.43 to 0.93 cm/yr

Radiological dose assessment due to hypothetical nuclear power plant operation in Mersing, Johor, Malaysia

Malaysia has considered for some time to adopt nuclear power to cater to the increasing demand of electricity following other developed Asian countries such as Japan, Korea, and China. In implementing a nuclear power plant, strict regulations and guidelines by the International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP) must be fulfilled before any construction license is given for a new nuclear power program. One of the assessments include the estimation of potential radiological risks to both humans and environment from routine and accidental release of radioactive effluent from the nuclear power plant (NPP). In this work, simulations of radionuclide dispersion from a hypothetical NPP site in Mersing, Johor will be presented. The simulation was performed based on the Lagrangian atmospheric dispersion model using the HYSPLIT software. The radioactive effluent release rate was approximated to the value found in the Fukushima Dai-ichi accident in 2011. Meteorological data of 2017 were utilized in this study. Simulation results showed that the dispersion of radioactive effluent from the hypothetical NPP can potentially affect areas around Johor Bahru district, Singapore, and even some areas in Indonesia

Development of radionuclide dispersion modeling software based on Gaussian Plume model

It has come to attention that Malaysia have been aiming to build its own nuclear power plant (NPP) for electricity generation in 2030 to diversify the national energy supply and resources. As part of the regulation to build a NPP, environmental risk assessment analysis which includes the atmospheric dispersion assessment has to be performed as required by the Malaysian Atomic Energy Licensing Board (AELB) prior to the commissioning process. The assessment is to investigate the dispersion of radioactive effluent from the NPP in the event of nuclear accident. This article will fo- cus on current development of locally developed atmospheric dispersion modeling code based on Gaussian Plume model. The code is written in Fortran computer language and has been benchmarked to a readily available HotSpot software. The radionuclide release rate entering the Gaussian equation is approximated to the value found in the Fukushima NPP accident in 2011. Meteorological data of Mersing District, Johor of year 2013 is utilized for the calculations. The results show that the dispersion of ra- dionuclide effluent can potentially affect areas around Johor Bahru district, Singapore and some parts of Riau when the wind direction blows from the North-northeast di- rection. The results from our code was found to be in good agreement with the one obtained from HotSpot, with less than 1% discrepancy between the two

Atmospheric trajectory analysis of cesium-137 from proposed nuclear power plant site in Bangka Island, Indonesia

Environmental risk assessment for nuclear power plant (NPP) operation is important to monitor the level of radionuclide concentration in the atmosphere and to determine the health risks associated with potential external radiation exposure. A NPP site was proposed in Bangka Island, Indonesia, 554 km from Johor Bahru, Malaysia. In the event of postulated nuclear emergency, the radionuclide dispersion from Bangka Island can possibly arrive in Malaysia’s atmosphere due to its close distance with Malaysian border. The purpose of this study is to assess the trajectories of Cs-137 radionuclide towards Malaysia from Bangka Island NPP site. A simulation was conducted using Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) to describe the movement of radionuclides in the atmosphere from Bangka Island towards Malaysia. The result shows the trajectories and direction of both radionuclides are very much affected by the monsoon season, as well as the meteorological characteristics such as wind speed and direction. In the simulated event of radioactive release in 2019, the trajectories can be seen moving directly towards Malaysia in May, June, July, August, September and October. It is concluded that if Indonesia were to proceed with the NPP construction in Bangka Island, necessary preparation such as emergency plan and risks mitigation should be strategized early in Malaysia to safeguard the public and the environment

Radioactive dispersion analysis for hypothetical nuclear power plant (NPP) candidate site in Perak state, Malaysia

Malaysia is planning to build a nuclear power plant (NPP) by 2030 to diversify the national electricity supply and resources. Selection of an NPP site must consider various factors, especially nuclear safety consideration to fulfil the nuclear safety objectives. Environmental Risk Assessment Analysis is a part of safety requirements by the International Atomic Energy Agency (IAEA) prior to the NPP commissioning process. Risk Assessments Analysis (RIA) is compulsory for the NPP site evaluation. One of RIA methods are Radioactive Dispersion Analysis using probabilistic risk analysis software. It is also important to perform studies to estimate the impact to the neighbouring population in the case of a nuclear accident at the power plant. In the present work, aimed to study the impact of a hypothetical nuclear accident by simulating the dispersion pattern of radionuclides originated from a candidate site at Manjung, Perak. The work has been performed using the HotSpot Health Physics codes. Two types of radionuclides have been considered namely 137Cs and 131I. In calculations, the initial concentration of radioactive materials of Fukushima Daiichi accident data are used which are 2.06 x 1016 Bq and 1.68 x 1017 Bq respectively for the two radionuclides. The result shows that the dispersion distance obtained from both software are not the same. It shows that 137Cs and 131I can be dispersed as far as 16 km and 80 km away from the site during radiological accident respectively, reaching major towns in Perak. Using HOTSPOT, the estimated total effective dose equivalent (TEDE) for 137Cs and 131I at major towns in Perak such as Lumut and Sitiawan are 1.2 mSv and 9.9 mSv. As for Taiping, Ipoh, Kampar, and Teluk Intan the estimated TEDE is around 0.2 mSv and 1.6 mSv respectively. In conclusion, the dispersion can reach as far as 80 km from the site. However, estimated annual effective dose is not more than 1 mSv limit, which is considered acceptable in the point of view of radiological health risk for human and the environment

Radioactive dispersion analysis for hypothetical nuclear power plant (NPP) candidate site in Perak state, Malaysia

Malaysia is planning to build a nuclear power plant (NPP) by 2030 to diversify the national electricity supply and resources. Selection of an NPP site must consider various factors, especially nuclear safety consideration to fulfil the nuclear safety objectives. Environmental Risk Assessment Analysis is a part of safety requirements by the International Atomic Energy Agency (IAEA) prior to the NPP commissioning process. Risk Assessments Analysis (RIA) is compulsory for the NPP site evaluation. One of RIA methods are Radioactive Dispersion Analysis using probabilistic risk analysis software. It is also important to perform studies to estimate the impact to the neighbouring population in the case of a nuclear accident at the power plant. In the present work, aimed to study the impact of a hypothetical nuclear accident by simulating the dispersion pattern of radionuclides originated from a candidate site at Manjung, Perak. The work has been performed using the HotSpot Health Physics codes. Two types of radionuclides have been considered namely 137Cs and 131I. In calculations, the initial concentration of radioactive materials of Fukushima Daiichi accident data are used which are 2.06 x 1016 Bq and 1.68 x 1017 Bq respectively for the two radionuclides. The result shows that the dispersion distance obtained from both software are not the same. It shows that 137Cs and 131I can be dispersed as far as 16 km and 80 km away from the site during radiological accident respectively, reaching major towns in Perak. Using HOTSPOT, the estimated total effective dose equivalent (TEDE) for 137Cs and 131I at major towns in Perak such as Lumut and Sitiawan are 1.2 mSv and 9.9 mSv. As for Taiping, Ipoh, Kampar, and Teluk Intan the estimated TEDE is around 0.2 mSv and 1.6 mSv respectively. In conclusion, the dispersion can reach as far as 80 km from the site. However, estimated annual effective dose is not more than 1 mSv limit, which is considered acceptable in the point of view of radiological health risk for human and the environment