Utilization of coal fly ash in solidification of liquid radioactive waste from research reactor

In this study, the potential utilization of fly ash was investigated as an additive in solidification process of radioactive waste sludge from research reactor. Coal formations include various percentages of natural radioactive elements; therefore, coal fly ash includes various levels of radioactivity. For this reason, fly ashes have to be evaluated for potential environmental implications in case of further usage in any construction material. But for use in solidification of radioactive sludge, the radiological effects of fly ash are in the range of radioactive waste management limits. The results show that fly ash has a strong fixing capacity for radioactive isotopes. Specimens with addition of 5–15% fly ash to concrete was observed to be sufficient to achieve the target compressive strength of 20 MPa required for near-surface disposal. An optimum mixture comprising 15% fly ash, 35% cement, and 50% radioactive waste sludge could provide the solidification required for long-term storage and disposal. The codisposal of radioactive fly ash with radioactive sludge by solidification decreases the usage of cement in solidification process. By this method, radioactive fly ash can become a valuable additive instead of industrial waste. This study supports the utilization of fly ash in industry and the solidification of radioactive waste in the nuclear industry.

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An ESCA and SEM Study of Changes in the Surface Composition and Morphology of Low-Calcium Coal Fly Ash as a Function of Aqueous Leaching

MRS Proceedings ◽

10.1557/proc-86-37 ◽

1986 ◽

Vol 86 ◽

Cited By ~ 3

Author(s):

Myra M. Soroczak ◽

H. C. Eaton ◽

M. E. Tittlebaum

Keyword(s):

Fly Ash ◽

Photoelectron Spectroscopy ◽

Surface Composition ◽

Coal Fly Ash ◽

Near Surface ◽

X Ray ◽

Sem Study ◽

Before And After ◽

New Material ◽

Surface Chemistries

ABSTRACTThe reactivity of coal fly ash is dependent on the chemical composition of the surface. As reactions occur the ash particle size decreases and new material is available for reaction. This means that the near-surface chemistry can also be important. In the present study the surface chemistries of three ashes are determined by x-ray photoelectron spectroscopy both before and after exposure to a hydrating/leaching environment. Scanning electron microscopy is used to reveal ash morphology. The concentration of sulfur, found at the ash surfaces as a sulfate, and sodium decreased after leaching while the amount of iron and aluminum increased. Other elements, including calcium, increased and decreased with leaching depending on which ash was analyzed. Changes which occurred in the ash morphology after the removal of leachable elements are discussed.

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Composition, morphology, properties of coal fly ash microspheres and their application for conditioning liquid radioactive waste

International Journal of Nuclear Energy Science and Technology ◽

10.1504/ijnest.2006.010643 ◽

2006 ◽

Vol 2 (1/2) ◽

pp. 8 ◽

Cited By ~ 6

Author(s):

N.N. Anshits ◽

A.N. Salanov ◽

T.A. Vereshchagina ◽

D.M. Kruchek ◽

O.A. Bajukov ◽

...

Keyword(s):

Fly Ash ◽

Radioactive Waste ◽

Coal Fly Ash ◽

Liquid Radioactive Waste

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Production of environmentally friendly sand-like products from granitoid waste sludge and coal fly ash for civil engineering

Journal of Cleaner Production ◽

10.1016/j.jclepro.2019.117880 ◽

2019 ◽

Vol 238 ◽

pp. 117880 ◽

Cited By ~ 3

Author(s):

Roy Nir Lieberman ◽

Yaniv Knop ◽

Natalia Moreno Palmerola ◽

Carmen Muñoz ◽

Haim Cohen ◽

...

Keyword(s):

Fly Ash ◽

Civil Engineering ◽

Coal Fly Ash ◽

Environmentally Friendly ◽

Waste Sludge

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APPLICATION OF NEUTRON ACTIVATION ANALYSIS IN CHARACTERIZATION OF ENVIRONMENTAL SRM SAMPLES

Indonesian Journal of Chemistry ◽

10.22146/ijc.21535 ◽

2010 ◽

Vol 9 (2) ◽

pp. 231-235 ◽

Cited By ~ 3

Author(s):

Diah Dwiana Lestiani ◽

Muhayatun Muhayatun ◽

Natalia Adventini

Keyword(s):

Neutron Activation Analysis ◽

Fly Ash ◽

Activation Analysis ◽

Neutron Activation ◽

Environmental Samples ◽

Coal Fly Ash ◽

Nuclear Industry ◽

Estuarine Sediment ◽

Energy Agency ◽

Nuclear Technique

Neutron activation analysis (NAA) is a nuclear technique that is excellent, multi-elemental, sensitive and has limit detection up to nanogram level. The application of NAA in analysis of Standard Reference Material (SRM) National Institute of Standard Technology (NIST) 1633b Coal Fly Ash and SRM NIST 1646a Estuarine Sediment was carried out for NAA laboratory inter-comparison program. The samples were distributed by Technology Centre for Nuclear Industry Material, National Nuclear Energy Agency as a coordinator of the inter-comparison program. The samples were irradiated in rabbit facility of G.A. Siwabessy reactor with neutron flux ~ 1013 n.cm-2.s-1, and counted with HPGe spectrometry gamma detector. Several trace elements in these samples were detected. The concentration of Al, Mg, K, Na and Ti in SRM NIST 1633b were 15.11, 7.35, 2.09, 0.192 and 0.756% respectively and the concentration of As, Cr, Mn, Se, V, Sb, Co, Cs, La, Sc and Sm were 137.0, 195.6, 129.4, 9.61, 305.8, 5.45, 56.2, 11.18, 83.73, 41.1 and 19.13 mg/kg respectively. The analysis result in SRM NIST 1646a of the concentration of Al and Na were 2.15 and 0.70% and the concentration of As, Cr, Co, La and Sc were 5.75, 36.3, 4.58, 15.67 and 4.00 mg/kg respectively. These results analysis had relative bias and u-test ranged from 0.4-11.3% and 0.15-2.25. The accuracy and precision evaluation based on International Atomic Energy Agency (IAEA) criteria was also applied. The result showed that NAA technique is applicable for the environmental samples analysis, and it also showed that the NAA laboratory in BATAN Bandung has a good performance. Keywords: NAA, inter-comparison, estuarine sediment, coal fly ash, environmental samples

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Optimization of Radioactive Waste Cementation for Decommissioning of Salaspils Research Reactor

ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2011-59066 ◽

2011 ◽

Author(s):

G. Abramenkova ◽

A. Abramenkovs ◽

M. Klavins

Keyword(s):

Fly Ash ◽

Radioactive Waste ◽

Research Reactor ◽

Mechanical Stability ◽

Cement Mortar ◽

Tritiated Water ◽

Mechanical Tests ◽

Solidification Temperature ◽

Optimal Interval ◽

Long Time

This paper deals with information on the radioactive waste cementation technology for decommissioning of Salaspils Research Reactor (SRR). Dismantled and segmented radioactive materials were cemented in concrete containers using tritiated water-cement mixture. The viscosity of water-cement mortar, mechanical tests of solidified mortar’s samples, change of temperature of the samples during solidification time and long time leakage of 137Cs, 14C, 60Co and 3T radionuclides was studied for different water-cement compositions with additives. The pH and electro conductivity of the solutions during leakage tests were controlled. It was shown, that water/cement ratio significantly influences on water-cement mortar’s viscosity and solidified samples mechanical stability. The role of additives — fly ash and Penetron admix in reduction of solidification temperature is discussed. It was found, that addition of fly ash to the cement-water mortar can reduce the solidification temperature from 81°C up to 62°C. The optimal interval of water ratio in cement mortar is discussed. Radionuclides leakage tests show that the release curves has a complicate structure. The possible radionuclides release mechanisms are discussed. Experimental results indicated that additives can significantly influence on the radionuclides release processes from cemented samples. The optimization of cementation of radioactive wastes in concrete containers was performed using mechanical stability, solidification temperature, radionuclide releases and viscosity of mortar.

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The effect of 60Co gamma irradiation on coal fly-ash geopolymer paste setting time

Nuclear Technology and Radiation Protection ◽

10.2298/ntrp2002150r ◽

2020 ◽

Vol 35 (2) ◽

pp. 150-153

Author(s):

Luka Rubinjoni ◽

Srboljub Stankovic ◽

Boris Loncar

Keyword(s):

Fly Ash ◽

Radioactive Waste ◽

Waste Treatment ◽

Low Cost ◽

Coal Fly Ash ◽

Setting Time ◽

Initial Setting Time ◽

Final Setting Time ◽

Intermediate Level Radioactive Waste ◽

Geopolymer Paste

Cementation is the baseline technology for conditioning of low to intermediate level radioactive waste. Geopolymers, a class of alkali activated binders, are a promising new material for radioactive waste treatment. Coal fly-ash based geopolymers are a low-cost, low greenhouse gas footprint alternative to metakaolin based materials. Both the grouting of sludge/powders/liquids and encapsulation of solids/compacted waste rely on the grout maintaining optimal flow (rheological properties) during the mixing and pouring operations, and achieving a set leading to proper long term solidification (mechanical properties). The initial and final setting time for fly-ash geopolymer paste, based on the SRPS EN 196-3 standard, has been measured upon irradiation by gamma rays in a 60Co reference field positioned with a kerma air rate of 3.42 mGys?1. The binder paste was prepared using fly-ash from the TENT B power plant's electrostatic filters without further sieving, activated by water glass with module 1.5 and mixed with distilled water until a satisfactory flow was obtained, and poured into the sample and control molds. The initial and final setting times for the irradiated sample and non-irradiated control were determined by the Vicat apparatus. The irradiated sample demonstrated an 11 % shorter initial setting time, and 16 % shorter final setting time, compared to the control.

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