The Energy and Exergy Analysis of the Reactor Unit of Boric Acid Production Process with ChemCAD Simulation

Energy and exergy analysis of systems are of great importance to enhance the energy and exergy efficiency of industrial production facilities. With the energy and exergy analyses performed, the energy dependency of the production facilities and their energy consumption can be reduced, the price of the product can decrease, and the profit margin can increase. Additionally, it is ensured that the energy produced based on fossil fuels is used in a controlled way. In the present study, the analysis of energy and exergy has been performed for the production reactor unit of the Boric Acid from Colemanite. The first law of thermodynamics and ChemCAD simulation program was used for energy analysis calculations, and the calculations of exergy analysis were carried out by using the second law of thermodynamics. The total energy loss of the reactor unit and the calculated energy loss per 100 kcal input steam were calculated as 110880 kcal/h and 3.724%, and the losses of total exergy in the reactor units and the losses of exergy calculated per 100 kcal input steam were calculated as 225058.86 kcal/h and 30.095%, respectively. Exergy efficiency for the reactor unit has been determined as 3.3 %. Some suggestions were given for the reactor units of boric acid production plants to minimize system losses.

Features of methods for monitoring the fuel cladding tightness in lead-cooled fast breeder reactors

To timely detect failed fuel elements, a reactor plant should be equipped with a fuel cladding tightness monitoring system (FCTMS). In reactors using a heavy liquid-metal coolant (HLMC), the most efficient way to monitor the fuel cladding tightness is by detecting gaseous fission products (GFP). The article describes the basic principles of constructing a FCTMS in liquid-metal-cooled reactors based on the detection of fission products and delayed neutrons. It is noted that in a reactor plant using a HLMC the fuel cladding tightness is the most efficiently monitored by detecting GFPs. The authors analyze various aspects of the behavior of fission products in a liquid-metal-cooled reactor, such as the movement of GFPs in dissolved and bubble form along the circuit, the sorption of volatile FPs in the lead coolant (LC) and on the surfaces of structural elements, degassing of the GFPs dissolved in the LC, and filtration of cover gas from aerosol particles of different nature. In addition, a general description is given of the conditions for the transfer of GFPs in a LC environment of the reactor being developed. Finally, a mathematical model is presented that makes it possible to determine the calculated activity of reference radionuclides in each reactor unit at any time after the fuel element tightness failure. Based on this model, methods for monitoring the fuel cladding tightness by the gas activity in the gas volumes of the reactor plant will be proposed.

Optimization of a Primary Heat Exchanger for FLiBe Molten Salt Nuclear Reactor With sCO2 Power System

One of the concepts being investigated for Generation IV nuclear reactors is the Molten Salt Reactor (MSR), with designs utilizing molten salts as both fuels and/or coolants. Historic development focused on large reactors, but contemporary efforts are likely to be small and modular, with this analysis considering 30 MWth per reactor unit For both cases, the use of a supercritical carbon dioxide (sCO2) Brayton cycle is being considered for power conversion. Compatibility of sCO2 power cycles with high turbine inlet temperature among several other advantages allows for several nuclear applications. This paper sought to optimize heat exchange between an MSR heat source and an sCO2 power cycle by thermalhydraulically optimizing a salt-heat exchanger sCO2 (HEX). This is accomplished using a one dimensional (1D) heat transfer code that solves for the geometry of a single pass shell-and-tube HEX, as well as pressure loss. Input to the HEX code are derived from a MSR technology assessment and from an optimized recuperated recompression (RRC) sCO2 power cycle. The HEX designs comprise of single shell and tubes with molten salt 2LiFBeF2 (FLiBe) flowing in the shell and sCO2 in the tubes. Hastelloy N is chosen for HEX material due to its tested compatibility with in nuclear application with FLiBe. Shell diameter and number of tubes are varied to optimize length of the HEX. Initial estimate for the weight of the HEX is then compared against the heat transfer area to further converge on an optimized design.

The method for calculating the probability of brittle destruction of NPP equipment in different operating modes with postulated defectiveness

The destruction of equipment metal by a brittle fracture mechanism is a probabilistic event at nuclear power plants (NPP). The calculation for resistance to brittle destruction is performed for NPP equipment exposed to neutron irradiation; for example, for a reactor plant such as a water-water energetic reactor (WWER), this is a reactor pressure vessel. The destruction of the reactor pressure vessel leads to a beyond design-basis accident, therefore, the determination of the probability of brittle destruction is an important task. The research method is probabilistic analysis of brittle destruction, which takes into account statistical data on residual defectiveness of equipment, experimental results of equipment fracture toughness and load for the main operating modes of NPP equipment. Residual defectiveness (a set of remaining defects in the equipment material that were not detected by non-destructive testing methods after manufacturing (operation), control and repair of the detected defects) is the most important characteristic of the equipment material that affects its strength and service life. A missed defect of a considerable size admitted into operation can reduce the bearing capacity and reduce the time of safe operation from the nominal design value down to zero; therefore, any forecast of the structure reliability without taking into account residual defectiveness will be incorrect. The application of the developed method is demonstrated on the example of an NPP reactor pressure vessel with a WWER-1000 reactor unit when using the maximum allowable operating loads, in the absence of load dispersion in different operating modes, and taking into account the actual values of the distributions of fracture toughness and residual defectiveness. The practical significance of the developed method lies in the possibility of obtaining values of the actual probability of destruction of NPP equipment in order to determine the reliability of equipment operation, as well as possible reliability margins for their subsequent optimization.

DEVELOPMENT OF VIRTUAL QUALITY ANALYZERS FOR THE ADVANCED PROCESS CONTROL SYSTEM OF THE REACTOR UNIT OF THE PENTANE HEXANE POLYMERIZATION UNIT

В данной статье рассматривается разработка виртуальных анализаторов качества для системы усовершенствованного управления технологическим процессом реакторного блока установки пентан гексановой изомеризации. Для этого были произведены вспомогательные вычисления, построены математические модели и реализация виртуальных анализаторов качества в программном продукте, представлены рисунки аппроксимации показаний с датчиков, наиболее влияющих на качество продукта. Продемонстрированы характеристики разработанных виртуальных анализаторов качества, результаты предварительного построения виртуальных анализаторов в программном обеспечении Honeywell. Приведено пошаговое тестирование, построение и отладка динамических моделей, конфигурация базового регулирования. Цель работы заключалась в анализе выгрузки данных с приборов исследуемого блока и на основе анализа данных построение регрессионных уравнений, необходимых для построения виртуальных анализаторов качества. В результате исследования были разработаны виртуальные анализаторы качества, предоставлены рисунки наложения данных модели на исторические данные приборов. This article discusses the development of virtual quality analyzers for the advanced process control system of the reactor unit of the pentane hexane isomerization unit. For this purpose, auxiliary calculations were made, mathematical models were built, and virtual quality analyzers were implemented in the software product. The characteristics of the developed virtual quality analyzers and the results of preliminary construction of virtual analyzers in the Honeywell software are demonstrated. Step-by-step testing, construction and debugging of dynamic models, configuration of basic regulation are given.

Modeling and Multi-Criteria Optimization of a Process for H2O2 Electrosynthesis

This article introduces a novel laboratory-scale process for the electrochemical synthesis of hydrogen peroxide (H2O2). The process aims at an energy-efficient, decentralized production, and a mathematical optimization of it is presented. A dynamic, zero-dimensional mathematical model of the reactor is set up in Aspen custom modeler®. The proposed model constitutes a reasonable compromise between complexity and convergence. After thoroughly determining the reaction kinetics by adjustment to experimental data, the reactor unit is embedded in an Aspen Plus® flowsheet in order to investigate its interaction with other unit operations. The downstream contains another custom module for membrane distillation. Electricity appears as a resource in the process, and optimization shows that it reaches product purities of up to 3 wt.-%. Both the process optimization and the adjustment of the reaction kinetics are treated as multi-criteria optimization (MCO) problems.