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"Dalam rangka mendorong pemanfaatan sumber energi baru dan terbarukan yaitu pembangunan PLTN, yang menimbulkan limbah radioaktif Cs-137 dengan T1/2 = 30 tahun. Cs-137 harus ditempatkan pada fasilitas disposal limbah radioaktif dengan bahan penghalang alami yang cocok untuk menghambat transport radionuklida ke lingkungan. Penelitian ini bertujuan untuk menganalisis pengaruh waktu kontak variasi 1-11 hari, konsentrasi Cs 10-8 ? 10-4 M, kekuatan ion yang diwakili NaCl dan KCl 0,1M, 0,5M dan 1 M pada sorpsi Cs-137 dengan tanah lempung formasi Karawang. Hasil sorpsi dengan metode batch, didapatkan waktu kesetimbangan pada hari ke-8 untuk TK-3 dan TK-5 dengan nilai koefisien distribusi (Kd) 21.714 ml/g dan 4.035 ml/g. Meningkatnya konsentrasi Cs-137 di larutan telah menurunkan nilai Kd. Keberadaan ion lain di larutan telah menurunkan nilai Kd Cs-137 dan kekuatan ion K+ lebih besar dibandingkan ion Na+ dalam menurunkan nilai Kd. Pada kedua jenis tanah lempung formasi Karawang menunjukkan kecocokan dengan isoterm Freundlich dan model kinetika orde dua semu.

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In order to encourage the utilization of new and renewable energy sources from construction of nuclear power plants, which generate radioactive waste Cs-137 with T1/2 = 30y. Cs-137 should be placed on radioactive waste disposal facility with a natural barrier (hostrock) that suitable for inhibiting the transport of radionuclides into the environment. The purpose of this research was to analyze the effects of contact time in variation of 1-11 days, the concentration of CsCl 10-8 ? 10-4 M, ionic strength represented NaCl and KCl 0,1M, 0,5M and 1M on Cs-137 sorption with clay of Karawang formation.

Results of sorption with batch methods, obtained equilibrium time on 8 days for the TK-3 and TK-5 with the value of the distribution coefficient (Kd) 21,714 ml/g and 4035 ml/g. The increasing concentrations of Cs-137 in solution had reduced the value of Kd. The presence of existence of other ions in solution had reduced the Kd value Cs-137 and the ionic strength of K+ is greater than Na+ on decreased the value of Kd. In both types of clay of formation Karawang were closely fit to Freundlich isotherm and pseudo-order kinetic model."

"Cs-137 is one of the most common radionuclides used for analysing man-made radioactive contamination in the environment beside Sr-90. Nangro Aceh Darussalam Province suffered the greatest mortality, with widespread destruction extending along more than 1000 km of coastline on 26 December 2004 due to tsunami. The disaster were affected areas about 220 km long and around 5 km wide along the coastlines of Aceh and North Sumatra. The purpose of this study is to investigate the artificial radioactivity 137Cs in soil samples which have been collected from various locations along the areas affected by tsunami in Aceh. The surface soil samples were collected from 20 sites in this region. The soil samples from the middle area of Aceh which was not exposed to the tsunami have also been investigated for comparison. The activity concentration of137Cs in the samples was measured using a ORTEC P-type coaxial high purity Germanium (HPGe) detector system. The artificial radioactivity level of 137Cs measured from these samples was found in the range of not detected to 2.09 Bq.kg-1 for the affected soil samples and 0.56 to 1.44 Bq.kg-1 for unaffected soil respectively. The radioactivity concentrations of 137Cs within the coastline areas are comparable to that of the middle area, which was not exposed to the tsunami. The results indicate that there are no new inputs of man-made radionuclides into the area at that time and the data obtained could serve as baseline levels of 137Cs in Aceh Region."

"Electric Arc Furnace Dust (EAFD) sebagai limbah dari pengolahan besi baja terkontaminasi oleh zat radioaktif Cs-137 secara tidak disengaja karena ketidakmampuan fasilitas pengolah melakukan deteksi terhadap keberadaanya. Masalah penelitian ini adalah pengelolaan EAFD sebagai material terkontaminasi radioaktif belum dinyatakan dapat dilakukan dengan aman dan selamat. Dalam penelitian ini dilakukan serangkaian analisis meliputi perhitungan konsentrasi aktivitas radionuklida, penetapan tingkat klierens, penerimaan masyarakat terhadap pengolahan material terkontaminasi radioaktif, keselamatan radiasi dan lingkungan serta nilai ekonomi dari pemanfaatan EAFD. Tujuan akhir dari penelitian ini adalah kegiatan pemanfaatan material tekontaminasi radioaktif dapat dilaksanakan secara berkelanjutan berdasarkan parameter keselamatan radiasi dan lingkungan, penerimaan masyarakat dan nilai ekonomi. Metode analisis penelitian menggunakan statistik deskriptif dan Structural Equation Modeling – Partial Least Square (SEM-PLS). Hasil riset ini adalah konsentrasi aktivitas radionuklida dari Cs-137 pada Paving Block berada dibawah tingkat klierens dan telah mendapatkan persetujuan badan pengawas untuk dapat mengelola EAFD terkontaminasi radioaktif. Penerimaan masyarakat dipengaruhi signifikan oleh manfaat yang dirasakan (perceived benefit) sebesar 63,1% dan risiko yang dirasakan (perceived risk) sebesar 0,16%. Produk Paving Block melewati nilai baku mutu TCLP A dan TCLP B untuk unsur Barium (Ba) yaitu sebesar 8,66 mg/L. Untuk unsur Chromium Hexavalent (Cr6+) berada pada level TCLP B yaitu sebesar 0,15 mg/L. Hasil uji kuat tekan menunjukan paving block tidak memenuhi uji kuat tekan sesuai semua mutu SNI 03-0691-1996 yaitu sebesar 7,36 Mpa (campuran 20% EAFD), 8,3 Mpa (campuran 25% EAFD) dan 7,19 Mpa (campuran 30% EAFD). Pemodelan Resrad Onsite 7.2 menunjukan nilai batas dosis sebesar 1 mSv/tahun bagi masyarakat tidak terlampaui untuk skema jalur pajanan radiasi eksternal, inhalasi dan soil ingestion. Nilai ekonomi dari pemanfaatan EAFD dalam pembuatan paving block tidak signifikan menurunkan harga produksi yaitu Rp. 2.213,77 per buah atau Rp. 97.405 per meter persegi. Mekanisme klierens mampu menghemat biaya pengelolaan material terkontaminasi radioaktif yaitu Rp. 572.137.153 jika dikelola sebagai limbah radioaktif.

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Electric Arc Furnace Dust (EAFD) as waste from steel processing is unintentionally contaminated with radioactive substance Cs-137 due to the inability of the processing facility to detect its presence. The problem of this research is that the management of EAFD as radioactive contaminated material has not yet been declared can be done safely. In the study, a series of analyses were carried out including the calculation of the concentration of radionuclide activity, the determination of clearance levels, public acceptance of the processing of radioactive contaminated materials, radiation and environmental safety and the economic value of the use of EAFD. The ultimate objective of this study is that the activities of the utilization of radioactive contaminated materials can be carried out sustainably based on radiation safety and environmental parameters, public acceptance and economic value. Methods of research analysis using statistical descriptives and Structural Equation Modeling – Partial Least Square (SEM-PLS). The result of this research is that the concentration of radionuclide activity of Cs-137 on the paving block is below the clearance level and has obtained regulatory approval to be able to manage radioactive contaminated EAFDs. Perceived benefits accounted for 63,1% and perceived risks for 0,16%. The paving block product passes the TCLP A and B quality standards for the barium (Ba) element, which is 8,66 mg/L. For the element Chromium Hexavalent (Cr6+) is at the level of TCLP B which is 0,15 mg/L. The pressure test results showed that the paving block did not meet the pressure test according to all SNI quality 03-0691-1996 which is of 7,36 Mpa (mixture 20% EAFD), 8,3 Mpa (25%) and 7,19 Mpa (30%) EAFD. The modeling of Resrad Onsite 7.2 shows the dose limit value of 1 mSv/year for the population not to be exceeded for external radiation exposition pathway schemes, inhalation and soil ingestion. The economic value of the use of EAFD in paving block production does not significantly lower the price of production, which is Rp. 2.213,77 per fruit or Rp. 97.405 per square meter. The cleerens mechanism can save the cost of managing radioactive contaminated material, which is Rp. 572.137.153 if managed as radioactive waste.."

"Lapisan tanah dan bentonit yang dipadatkan digunakan sebagai salah satu lapisan pondasi rekayasa di fasilitas disposal yang berfungsi untuk mencegah pelepasan Cs-137 dari fasilitas disposal ke zona tak jenuh. X-Ray Fluorescence (XRF) dan X-ray Diffraction (XRD) digunakan untuk mengkarakterisasi tanah dan bentonit lokal yang diteliti. Dari analisis XRF dan XRD, kedua sampel tersebut tersusun dari Montmorillonit dan tanah setempat mengandung Kaolinit dalam jumlah yang cukup besar. Untuk mengevaluasi koefisien difusi (Da) Cs-137 pada sampel tanah dan bentonit yang dipadatkan, digunakan model perpindahan Cs-137 secara difusi dengan posisi vertikal. Koefisien difusi ditentukan secara eksperimental dalam unit kolom difusi di bawah variasi waktu difusi dan kondisi densitas. Dalam penelitian ini, persamaan Hukum Fick’s digunakan untuk menentukan nilai Da sampel. Hasil yang diperoleh menunjukkan bahwa kisaran koefisien difusi adalah 3 x 10-12 sampai 5 x 10-13 m2/s untuk sampel tanah dan bentonit, masing-masing tergantung pada kepadatannya, namun tidak tergantung pada waktu difusi. Hasilnya menunjukkan bahwa Cs-137 secara bertahap bergerak ke bagian tanah yang lebih dalam seiring waktu. Juga diamati bahwa koefisien difusi untuk sampel tanah lebih tinggi 101 daripada bentonit. Rendahnya Da pada sampel bentonit dapat mengimplikasikan bahwa porositas bentonit menjadi lebih kecil daripada sampel tanah karena sifat swelling pada sampel bentonit.

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The compacted soil and bentonite layers are used as one of the engineering foundation layers in the disposal facility which serves to prevent the release of Cs-137 from the disposal facility to the unsaturated zone. X-Ray Fluorescence (XRF) and X-ray Diffraction (XRD) were used to characterize the soil and local bentonite studied. From the analysis of XRF and XRD, both samples were composed of Montmorillonit and the local soil contained a considerable amount of Kaolinite. To evaluate the diffusion coefficient (Da) Cs-137 in compacted soil and bentonite samples, a diffusion model of displacement Cs-137 with a vertical position was used. The diffusion coefficient is determined experimentally in diffusion column units under variations in diffusion time and density conditions. In this study, the Equation of Fick's Law was used to determine the Da value of a sample. The results obtained showed that the range of diffusion coefficients is 3 x 10-12 to 5 x 10-13 m2/s for soil and bentonite samples, each of which depends on its density, but does not depend on the time of diffusion. The results showed that Cs-137 gradually moved to the deeper parts of the ground over time. It was also observed that the diffusion coefficient for soil samples was 101 higher than for bentonite. The low Da in bentonite samples may imply that the porosity of bentonite becomes smaller than in soil samples due to the swelling properties of bentonite samples"