Sains Malaysiana 38(3): 407-411(2009)

Hazard Radiologi Radionuklid Tabii Dalam Simen

Portland Semenanjung Malaysia

(Radiological hazard of natural radionuclide in Portland

cement of Peninsular Malaysia)

Aznan Fazli Ismail*, Muhamad Samudi Yasir, Amran Ab. Majid,

Redzuwan Yahaya, Ismail Bahari

Program Sains Nuklear, Fakulti Sains Dan Teknologi

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia

Received: 16 July 2008 / Accepted: 23 August 2008

ABSTRAK

Selain daripada batu-batu kecil, batu kerikil dan pasir, simen merupakan salah satu bahan penting untuk membina bangunan. Simen diperbuat daripada campuran batuan dan tanah dan diketahui secara semulajadinya mengandungi radionuklid tabii. Kajian ini bertujuan untuk menentukan aras keradioaktifan tabii serta menilai hazard sinaran yang berpunca daripada radionulid tabii di dalam simen Portland di Malaysia. Sampel simen Portland diperolehi dari kilang pengeluar simen atau dibeli di pasaran tempatan. Kepekatan radionuklid tabii bagi ²²⁶Ra (siri ²³⁸U), ²³²Th dan ⁴⁰K ditentukan dengan menggunakan spektrometri sinar gama. Hasil kajian mendapati julat kepekatan aktiviti bagi ²²⁶Ra (siri ²³⁸U), ²³²Th dan ⁴⁰K masing-masing adalah 7.76 – 82.91 Bq kg^-1, 9.79 – 49.37 Bq kg^-1 dan 81.89 – 377.10 Bq kg^-1. Purata nilai kesetaraan radium berada dalam julat 35.36 ± 0.60 hingga 135.94 ± 15.27 Bq kg^-1 manakala julat purata bagi dos setara tahunan dan indeks hazard dalaman adalah masing-masing ialah 80  ± 2 hingga 300 ± 30 µSv tahun^-1 dan 0.12 ± 0.00 hingga 0.56 ± 0.07

Kata kunci: Hazard sinaran; keradioaktifan tabii; simen Portland

ABSTRACT

Besides bricks, granites and sands cement is one of the main components of building materials Cement is made from a combination of rocks and soils which is known to contain natural radioactivity. The objectives of this study were to determine the level of natural radioactivity and associated radiological hazard caused by natural radioactivity in Malaysia’s Portland cements. Portland cements samples were obtained from the manufacturers or bought directly from local hardware stores. Natural radionuclide concentrations of ²²⁶Ra (²³⁸U series), ²³²Th and ⁴⁰K were determined using gamma-ray spectrometry.  Activity concentrations of ²²⁶Ra (²³⁸U series), ²³²Th and ⁴⁰K were found in the range of 7.76 – 82.91 Bq kg^-1, 9.79 – 49.37 Bq kg^-1 dan 81.89 – 377.10 Bq kg^-1 respectively. Radium equivalent were found in the range of 35.36 ± 0.60 to 135.94 ± 15.27 Bq kg^-1 while the average annual equivalent dose and internal hazard index were found in the range of 80  ± 2 to 300 ± 30 µSv year^-1 and 0.12 ± 0.00 to 0.56 ± 0.07 respectively.

 Keywords : Natural radioactivity; Portland cement;  radiation hazard

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*Corresponding author; email: aznan-sn@yahoo.com