Effect of seawater intrusion on radioactive strontium (90Sr) sorption and transport at nuclear power plants

2018 ◽  
Vol 106 (2) ◽  
pp. 147-160
Author(s):  
Seeun Chang ◽  
Wooyong Um ◽  
Won-Seok Kim ◽  
HyunJu Kim

Abstract Batch sorption and column experiments were conducted to investigate and compare sorption and transport behavior of 90Sr on the assumption of seawater intrusion at nuclear power plants. Batch sorption experiments were carried out on fractured rocks and bedrocks using synthetic groundwater and seawater both spiked with 90Sr. In general, higher 90Sr sorption occurred on fractured rock samples than on bedrocks, because of the presence of weathered secondary minerals (iron oxide and clay) on fractured rock surfaces. However, one particular bedrock sample (WSP-B) which has higher porosity and carbon amount than fractured rock samples also showed the higher 90Sr sorption than its comparable fractured rocks. For all batch sorption studies, 90Sr sorption distribution coefficient, Kd decreased from groundwater to seawater environment due to the higher ionic strength of seawater (6.4×10−1–7.7×10−1 M) compared to groundwater (4.0×10−3–6.0×10−3 M). The three different ionic strength solutions were used in column experiments, and the results showed that transport behavior of Sr through a fractured rock had similar sorption trend to batch sorption results. The highest mobility (or least retardation) for Sr was found for 100% seawater solution compared to the highest retardation (or least mobility) for 100% groundwater solution. These sorption and transport data of Sr on solid materials contacted with various ionic strength solutions corroborate empirically defensible information for assessment of radioactive contamination in groundwater below the NPP sites located nearby shores. In addition, the experimental data will be incorporated to improve transport models of 90Sr in the subsurface environment for severe nuclear accidents.

Author(s):  
Marjorie B. Bauman ◽  
Richard F. Pain ◽  
Harold P. Van Cott ◽  
Margery K. Davidson

2010 ◽  
pp. 50-56 ◽  
Author(s):  
Pablo T. León ◽  
Loreto Cuesta ◽  
Eduardo Serra ◽  
Luis Yagüe

Author(s):  
R. Z. Aminov ◽  
A. N. Bayramov ◽  
M. V. Garievskii

The paper gives the analysis of the problem of the primary current frequency regulation in the power system, as well as the basic requirements for NPP power units under the conditions of involvement in the primary regulation. According to these requirements, the operation of NPPs is associated with unloading and a corresponding decrease in efficiency. In this regard, the combination of nuclear power plants with a hydrogen complex is shown to eliminate the inefficient discharge mode which allows the steam turbine equipment and equipment of the reactor facility to operate in the basic mode at the nominal power level. In addition, conditions are created for the generation and accumulation of hydrogen and oxygen during the day, as well as additionally during the nighttime failure of the electrical load which allows them to be used to generate peak power.  The purpose of the article is to assess the systemic economic effect as a result of the participation of nuclear power plants in combination with the hydrogen complex in the primary control of the current frequency in the power sys-tem, taking into account the resource costs of the main equipment. In this regard, the paper gives the justification of cyclic loading of the main equipment of the hydrogen complex: metal storage tanks of hydrogen and oxygen, compressor units, hydrogen-oxygen combustion chamber of vapor-hydrogen overheating of the working fluid in the steam turbine cycle of a nuclear power plant. The methodological foundations for evaluating the working life of equipment under cyclic loading with the participation in the primary frequency control by the criterion of the growth rate of a fatigue crack are described. For the equipment of the hydrogen complex, the highest intensity of loading is shown to occur in the hydrogen-oxygen combustion chamber due to high thermal stresses.  The system economic effect is estimated and the effect of wear of the main equipment under cyclic loading is shown. Under the conditions of combining NPP power units with a hydrogen complex, the efficiency of primary reg-ulation is shown to depend significantly on: the cost of equipment subjected to cyclic loading; frequency and intensity of cyclic loading; the ratio of the tariff for peak electricity, and the cost of electricity of nuclear power plants.  Based on the developed methodology for assessing the effectiveness of the participation of nuclear power plants with a hydrogen complex in the primary frequency control, taking into account the damage to the equipment, the use of the hydrogen complex is shown to provide a tangible economic effect compared with the option of unloading nuclear power plants with direct participation in frequency control.


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