ABSTRACTDetermination of element contents in fly ash from the coal power plant industry at Java Island has been performed by the method of Neutron Activation Analysis (NAA). Fly ash was sampled at Electrostatic Precipitator (EP) outlet by using isokinetic probe. Collected fly ash was mixed for 2 minutes and dried using oven at temperature of 105ºC for 2 hours. Fly ash and NIST Standard Reference Material (SRM) 1633b Coal Fly ash were put into polyethylene vials of 0.273 mL with various weights of 11.01-11.24 mg, 16.94-17.34 mg and 29.97-30,27 mg respectively according to the time of irradiation. The samples were put in polyethylene capsules and then irradiated at Rabbit System of Siwabessy Multipurpose Reactor of BATAN at the Power of 15 MW (flux of neutron was 1013 n.cm-2.s-1) for 1 minute (short irradiation), 15 minutes (middle), and 3 hours (long). The content of elements in these samples was then measured by using gamma spectrometer with HPGe detector of Canberra and was analyzed with Genie 2000 and Maestro shoftwares. The result showed that fly ash from coal power plant contained mayor elements : Mg, Al, Ca, Ti, Mn, Fe, Sr and Na with the concentrations of 5,572 - 20,636 mg/kg; 36,353 -140,972 mg/kg; 27,729 - 144,296 mg/kg; 3,680 - 7,325 mg/kg; 624 - 9,515 mg/kg; 62,454 - 114,325 mg/kg, 628.0 - 1.775 mg/kg and 995.0 - 12,640 mg/kg; and minor elements detected were Se, Cs, Zn, V, Cr, Hg, Th, Sc, As, Sr, U, Co, Nd, Hf, Rb, Sb and La at the concentrations of 2.94-76.5 mg/kg. Keywords: element content, fly ash, Neutron Activation AnalysisABSTRAKTelah dilakukan penentuan kandungan unsur pada cuplikan fly ash (abu terbang) pada industri PLTU batubara di Pulau Jawa dengan metode analisis aktivasi neutron (AAN). Abu terbang setelah melewati Electrostatic Precipitator (EP) dicuplik menggunakan probe isokinetik. Cuplikan yang terkumpul dikocok selama dua menit dan dikeringkan dalam oven pada suhu 105ºC selama 2 jam. Cuplikan abu terbang dan Standard Reference Material (SRM) NIST 1633b Coal Fly ash masing-masing dimasukkan dalam vial polietelin ukuran 0,273 ml dengan berat 11,01-11,24 mg, 16,94-17,34 mg dan 29,97-30,27 mg masing-maing untuk waktu iradiasi yang berbeda. Vial abu terbang dan vial SRM kemudian dimasukkan dalam kapsul polietilen dan kemudian diiradiasi pada Rabbit System Reaktor Serbaguna Siwabessy BATAN pada Daya 15 MW (fluks neutron 1013 n.cm-2.s-1) selama 1 menit (iradiasi pendek), 15 menit (iradiasi menengah), dan 3 jam (iradiasi panjang). Sampel hasil iradiasi pendek selanjutnya dicacah menggunakan Spektrometer Gamma dengan detektor HPGe buatan Canberra dan sampel iradiasi menegah dan panjang menggunakan HPGe buatan Ortec Model Gem-60 dan selanjutnya dianalisis menggunakan perangkat lunak Genie 2000 dan MAESTRO. Hasil analisis menunjukkan bahwa cuplikan abu terbang dari PLTU batubara mengandung unsur mayor Mg, Al, Ca, Ti, Mn, Fe, dan Na dengan konsentrasi masing-masing adalah 5.572 – 20.636 mg/kg; 36.353 – 140.972 mg/kg; 27.729-144.296 mg/kg; 3.680-7.325; 624-9.515 mg/kg, 62.454-114.325 mg/kg, 628,0–1.775 mg/kg dan 995,0- 12.640 mg/kg, sedangkan unsur-unsur minor yang terdeteksi yaitu : Se, Cs, Zn, V, Cr, Hg, Th, Sc, As, Sr, U, Co, Nd, Hf, Rb, Sb dan La dengan konsentrasi 2,94-76,5 mg/kg.Kata kunci: kandungan unsur, abu terbang, analisis aktivasi neutron.
On-site field tests for study of low-rank western coal fly ash. Technical summary report, field test No. 3. Big Brown Station electrostatic precipitator