No abstract

KARAKTERISASI LIMBAH DARI PRODUKSI RADIOISOTOP MOLIBDENUM-99.  Radioisotop 99Mo diproduksi terutama sebagai radioisotop induk untuk memperoleh radioisotop tecnisium-99m (99mTc). Radioisotop 99mTc dipakai dalam kedokteran nuklir antara lain  untuk diagnosis pada kelainan tulang, otak, thyroid, paru-paru, hati dan ginjal. Di Indonesia 99Mo diproduksi oleh PT. Industri Nuklir Indonesia (INUKI) dari target uranium yang dilekatkan kedalam dinding kapsul baja tahan karat untuk kemudian diiradiasi di Reaktor GA Siwabessy. Pengambilan 99Mo dalam target dilakukan dengan proses CINTICHEM. Pada proses CINTICHEM akan ditimbulkan  beberapa jenis limbah yang salah satunya adalah Radioactive Fission Waste (RFW). Limbah ini memiliki paparan radiasi yang besar yang mengakibatkan karakterisasi limbah secara laboratorium sulit dilakukan. Pengelolaan limbah yang tepat memerlukan karakteristik limbah yang tepat pula. Oleh karena itu dalam penelitian ini dilakukan karakterisasi limbah RFW menggunakan program komputer ORIGEN 2.1 dengan data parameter input adalah data dari salah satu batch produksi 99Mo di PT INUKI yang berupa data target uranium diperkaya tinggi 92,7% yang dilekatkan pada kapsul baja tahan karat AISI 304L, iradiasi dilakukan pada posisi Centre Irradiation Position (CIP) dalam Reaktor Serbaguna GA Siwabessy dengan fluks netron termal: 1,12x1014 n/cm2detik dan iradiasi target dilakukan selama 96 jam. Seleksi radionuklida yang relevan terhadap metode pengelolaan limbah dilakukan berdasarkan pada waktu paro, tingkat kliren dan radiotoksisitas. Hasil penelitian menunjukkan bahwa sampai dengan waktu peluruhan 50 tahun, total konsentrasi aktivitas limbah 3,01x109 Bq/g dengan kandungan radionuklida produk aktivasi, aktinida dan anak luruhnya serta produk fisi. Selain itu limbah ini juga mengandung 235U yang masih cukup besar serta radionuklida umur paro panjang dengan tingkat toksisitas yang sangat tinggi. Berdasarkan pada Peraturan Pemerintah No.61 Tahun 2013 limbah ini diklasifikasikan sebagai limbah radioaktif  tingkat sedang dan memerlukan pengelolaan dengan tingkat keselamatan yang tinggi.

Due to depletion of conventional fuel and increasing global warming, biomass wastes have been explored and investigated by many researchers worldwide. A biomass gasification power plant is a promising conversion technology for energy sustainability. From many existing gasifiers have been developed, mostly they have high technology, large capacity, and very costly, thus unsuitable for remote area di Indonesia. The present work aims to build a simple and low cost double air-stage downdraft gasifier for a small-scale biomass power plant system. The gasifier is tested on rice husk at equivalence ratio of 0.20, 0.30, and 0.40. The parameters evaluated are axial temperature, fuel consumption rate, heating rate, thermal efficiency, and tar content. The results show that the highest gasification temperature, fuel consumption rate, heating rate, and thermal efficiency are occurs at equivalence ratio of 0.4. The values are 904.5°C, 4.14 kg/h, 25.38 kJ/h, and 63.18%, respectively. The significant findings is that the gasifier generates producer gas with low tar content, i.e. 23.9 mg/m3 at equivalence ratio of 0.4 and the producer gas is successfully used to run the 3 kW generator set. For sustainability operation of the power plant, it is important to test the gasifier on various biomass waste feedstocks.

The various internal qualities attributes of fruits and vegetables were able to be predicted nondestructively by using near infrared spectroscopy techniques. The objective of this study was to develop a calibration model for prediction of starch content, soluble solids content and water content of mango fruit by using near infrared spectroscopy and chemometric. The reflectance spectra of mango fruit were obtained in the wavelength range from 1000 nm to 2500 nm. The effects of different pre-process methods and spectra treatments, such as smoothing 3 points (sa3), first derivative Savitzky-golay 9 points (dg1), and combination of smoothing 3 points (sa3) and first derivative Savitzky-golay 9 points (dg1) were analyzed. The prediction models were developed by partial least square regression (PLS). The results show that the correlation coefficient, standard error calibration and consistency for starch content of 0.95, 1.20% and 86.89% were achieved using pre-process of first derivatif Savitzky-golay 9 points; for soluble solid content of 0.90, 1.34 o Brix and 86.24% were achieved using combination of smoothing 3 points and first derivatif Savitzky-golay 9 point and for water content of 0.78, 0.850 % and 99.74% were achieved using smoothing 3 points. This showed the capability of near infrared spectroscopy and the important role of chemometric in developing accurate models for the prediction of internal quality characteristics of mango fruit. AbstrakKualitas internal dari produk buah dan sayuran mampu dievaluasi dengan baik secara non destruktif menggunakan metode spektroskopi near infrared. Tujuan dari penelitian ini adalah untuk mengembangkan model kalibrasi untuk memprediksi kandungan pati, total padatan terlarut dan kadar air buah mangga selama penyimpanan menggunakan spektroskopi near infrared dan kemometrik. Spektra reflektan buah mangga diukur pada panjang gelombang 1000 nm sampai 2500 nm. Pengaruh metode pra-proses data yaitu penghalusan 3 titik, turunan pertama Savitzky-golay 9 titik, serta kombinasi penghalusan 3 titik dengan turunan pertama Savitzky-golay 9 titik terhadap ketelitian model kalibrasi juga dianalisis. Model prediksi dikembangkan dengan menggunakan regresi partial least square (PLS). Model prediksi dengan spektroskopi near infrared yang dikembangkan menghasilkan koefisien korelasi, standard error calibration (SEC) dan konsistensi untuk kandungan pati adalah 0.95, 1.20%, dan 86.89% yang diperoleh dari data praproses turunan pertama Savitzky-golay 9 titik, untuk total padatan terlarut, yaitu 0.90, 1.34 o Brix, dan 86.24% yang diperoleh dengan menggunakan kombinasi antara penghalusan 3 titik dan turunan pertama Savitzkygolay 9 titik, sedangkan untuk kadar air yaitu 0.78, 0.850%, dan 99.74% diperoleh dengan menggunakan penghalusan 3 titik. Dapat disimpulkan bahwa model prediksi spektroskopi near infrared untuk menduga kandungan internal dari buah mangga arumanis telah dikembangkan dengan baik.Kata kunci: spektroskopi near infrared, kualitas internal, kemometrik, mangga, non destruktif

The purpose of this study was to measure the performance of service quality by using students' perceptions of service quality performance at the

A key issue contributing to the success of NPP technology is the safe handling of radioactive waste, particularly spent nuclear fuel. According to the IAEA safety standard, the spent fuel must be stored in interim wet storage for several years so the radiation and the decay heat of the spent fuel will decrease to the safe limit values, after which the spent fuel can be moved to dry storage. In this study, we performed a theoretical analysis of heat removal by natural convection airflow in spent nuclear fuel dry storage. The temperature difference between the air inside and outside dry storage produces an air density difference. The air density difference causes a pressure difference, which then generates natural airflow. The result of the theoretical analysis was validated with simulation software and experimental investigation using a reduced-scale dry storage prototype. The dry storage prototype consisted of a dry cask body and two canisters stacked to store materials testing reactor (MTR) spent fuel, which generates decay heat. The cask body had four air inlet vents on the bottom and four air outlet vents at the top. To simulate the decay heat from the spent fuel in the two canisters, the canisters were wrapped with an electric wire heater that was connected to a voltage regulator to adjust the heat power. The theoretical analysis results of this study are relatively consistent with the experimental results, with the mean relative deviation (MRD) values for the prediction of air velocity, the heat rate using natural airflow, and the heat rate using the thermal resistance network equation are +0.76, −23.69, and −29.54%, respectively.

No abstract

EVALUATION OF NEUTRON SHIELDING PERFORMANCE OF CD-SS 316L AS A CANDIDATE ALLOY FOR DRY CASK OF RESEARCH REACTOR SPENT FUEL Development of dry casks is necessary to support the national strategy for management of spent fuels. One of the requirements for the dry cask is shielding performance for neutron emitted by the spent fuels to be stored in the dry cask. The objectives of this study are to determine the emitted neutrons by the spent fuel generated from GAS research reactor and to evaluate the neutron shielding performance of Cd-SS316L alloy as a candidate material to be used in dry cask for the spent fuels.  The former was carried out using Origen 2.1 software, while the latter using MCNP5. The result shows that the emitted neutrons by a spent fuel after 5 years discharged from GAS research reactor were 2.81×103 and 3.32×106 n/s for reactor core power of 15 and 30 MW, respectively. Addition of Cd improves the neutron shielding performance of SS 316L. The evaluation of neutron shielding performance of SS 316L with addition of Cd which is the candidate material for dry cask of the spent fuels from the GAS research reactor can be evaluated using Origen 2.1 software for neutron emission, while the neutron shielding performance was evaluated by the simulation using MNCP 5 software. This study shows the Cd-SS 316L alloy can be used for further study to develop the dry cask design for the GAS research reactor.Key words: Neutron shielding, cadmium, stainless steel, spent fuel.