Multifunctional Backup for NPP Internal Needs

2019

Electricity markets are changing because of (1) the addition of wind and solar that creates volatile electricity prices including times of zero-priced electricity and (2) the goal of a low-carbon world that requires replacing fossil fuels that provide (a) energy, (b) stored energy, and (c) dispatchable energy. Wind and solar provide energy but not the other two other energy functions that are provided fossil fuels. Nuclear energy with heat storage can provide all three functions and thus replace fossil fuels. iii Two storage technologies were examined that are incorporated into advanced Brayton power cycles. One proposes to use cold water to boost power when needed. The other uses a thermodynamic peaking cycle with incremental heat-toelectricity efficiencies of 70 to 75% when coupled to high-temperature reactors providing heat to the lower-temperature bottoming cycle. The heat for the topping cycle can be provided by natural gas, hydrogen, or stored heat produced by converting low-price electricity into high-temperature stored heat. A nuclear plant capable of producing, selling and buying electricity is different than any existing plant. There are large incentives to demonstrate heat storage in existing light water reactors to improve light water reactor economics and address many of the operational, grid, and regulatory challenges that are common to all heat storage systems coupled to nuclear plants. There are large incentives for joint nuclear/CSP heat storage development and demonstration programs because the same technologies are being used.

Science and Technology of Nuclear Installations, 2008

Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP) safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs), like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs) is resorted to mitigate consequences of station blackout (SBO). In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR) system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT), SGs, and PDHRs) under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections). On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.

2004

The paper introduces a risk monitoring solution for a NPP protection system. The two main functions of the solution, the Status Monitoring System and the Risk Monitoring System are described, as well as the possible improvements to enhance system performance and shorten the response time.

This Review paper states that the concept of a nuclear power plant. Nuclear power can solve the energy trilemma of supplying baseload, clean and affordable power. However, a review of nuclear power plant (NPP) builds show mixed results, with delays in Finland and the US offset by successes in China, South Korea and the UAE. In the West, financing for new builds has been difficult in the face of a deregulated energy market, billion-dollar upfront investments, long build times and in the case of the US historically low gas prices. We explore how the nuclear industry is innovating in facing these challenges through a review of nuclear power developments in the past, present and future. Early developments in nuclear power in the 1950s resulted in a variety of designs, out of which the pressurized water reactor (PWR) became dominant for its compactness and overall economy. Over the next 10 years, several PWR-based small modular reactor (SMR) designs are expected to come online within an eight-year timeframe. Their modular construction and fabrication in a controlled factory setting aims to shorten build times from 8 to 3 years. However, the lack of established regulatory approval pathways may be a time-limiting challenge that needs to be overcome by the first fleet of SMRs. The passive safety and a smaller fuel loading of SMRs will allow them to be deployed at more potential sites, including brownfield replacements of old coal-fired power plants or power unconventional, remote or islanded grids. Some SMRs are also designed to load follow which will allow them to work harmoniously with intermittent renewables sources with the promise of an affordable, truly carbon-neutral grid. In the longer term, advanced nuclear reactors in the form of sodium-cooled, molten salt cooled, and high-temperature gas-cooled reactors hold the promise of providing efficient electricity production, industrial heat for heavy industry as well as the generation of hydrogen for synthetic fuel. CURRENT NUCLEAR POWER There are currently 454 nuclear power reactors supplying more than 10% of the world's electricity, operating at a high capacity factor of 81% (2017 world average). 31 countries operate nuclear power plants (NPP) with 70% of the world's nuclear electricity generated in five countries-USA, France, China, Russia and South Korea. Today, the average age of the operational power reactors stands at 30 years with over 60% of all NPPs having operated for more than 31 years. Fig. 1. Total net capacity of nuclear power under construction Reactors (GCRs) at 3% with 14 units in the UK and two Sodium fast Neutron Reactors (SFRs) at 1% operating in Russia. Currently, 54 power reactors are under construction, the bulk of which is concentrated in Asia (figure 1) and one-third of all reactors under construction are in China. NPP builds are also underway in the West, but in more modest numbers as the industry revives its nuclear supply chain left dormant from the slow rate of build over the last 20 years. HISTORY OF NPP BUILDS Nuclear energy production releases no CO 2 , however the initial build out of NPPs was motivated by the

Energy Conversion and Management, 2019

Increasing electricity production by solar and wind energy is projected to impact the stability of electricity grids and consequently may limit the growth of renewable electricity generation. This issue can be ameliorated in part by increasing the flexibility of baseload power plants. A thermodynamic analysis of thermal energy storage (TES) coupled with a nuclear-powered Rankine cycle as one approach of increasing baseload flexibility is presented. During periods of excess capacity, the high-pressure steam supply is used to charge the TES. When electricity generation above the baseload capacity is required, the TES is discharged to generate steam for expansion in the low-pressure turbine. Pressure, temperature, and enthalpy state points within the cycle are presented over a range of charge and discharge rates. The capacity factor over a charge/discharge cycle is up to 9.8% higher than that of the same plant operated with steam bypass. This benefit increases with increasing charge and discharge power. With TES, the thermal-to-electrical efficiency is stable over a wide range of discharge rates. The results support future development of TES systems for baseload thermal power plants in a power grid in which renewable energy is prioritized.

2009

Thermal Engineering, 2006

We present the results from a technical and economic assessment of providing redundant power supply to the auxiliaries of a nuclear power station by equipping it with continuously operating gas-turbine units with recovering of the heat of spent gases in the nuclear power station's thermal circuit.

Isa Transactions, 1997

Korea Electric Power Corporation (KEPCO), the sole utility company in Korea, has been designing a large class of nearly identical 500 MW power plants as part of its standard design. These power plants each of which is capable of daily startup and shutdown operation, are being constructed and operated specifically to meet the large daily swings in power demand in Korea. Each power plant in this class is of a 500 MW output design, with a coal/oil firing furnace and a once-through, supercritical boiler.To address the concern of startup time in a large power plant after being off-line for eight to ten hours of night time, a steam bypass system (HP Bypass System) is being utilized. The HP Bypass System performs four functions: (1) it shortens the unit startup time; (2) it controls the main steam pressure during normal on-line operation; (3) it maintains the main steam at minimum threshold conditions while the turbine/generator is off-line; (4) it performs the safety function of protecting against steam line overpressurization, which eliminates the need for high pressure safety/relief valves.In this paper the standard 500 MW power plant design in Korea, the daily startup and shutdown design criteria, and the HP Bypass control with safety functions will be discussed.

International Journal of Electrical and Computer Engineering (IJECE), 2025

The performance of an atomic facility depends on the efficient supply of electricity, particularly emergency loads like monitoring and control equipment, radiation safety systems, and emergency lights. Most nuclear facilities rely on diesel generators to supply emergency loads during grid outages. Due to the diesel generator's imperfections, such as its starting time, it may fail to deliver power because it is unavailable due to maintenance, failure to start, or failure to run and supply the load. It cannot immediately supply the critical loads, resulting in a blackout and the release of radioactive substances into the environment. To address the previous issues, this paper proposes an improved method to enhance the reliability of nuclear facilities for providing electricity to safety and critical consumers during normal and emergency operating modes. The approach incorporates a photovoltaic (PV) system/battery, and its robustness and performance are tested using load flow and transient stability analysis. The simulation results demonstrated the effectiveness and speed of the proposed method when compared to the traditional method, as the emergency consumers were successfully powered within a very short time without fluctuations, and the voltage reduction and frequency were within the nominal values. The electrical transient analyzer program (ETAP) is used to validate these results.

2011

The CANDU®6 nuclear power reactor design has been in commercial operation since the 1980s and is currently in operation in several countries, including Canada, Argentina, South Korea, China and Romania. CANDU 6 is the proven, mid size version of the CANDU Pressurized Heavy Water Reactor (PHWR). With a gross electrical output in excess of 720 MWe, the CANDU 6 fits easily into most grids. The CANDU design uses natural uranium fuel. Other fuel types can be used, including slightly enriched uranium (SEU), recovered uranium (RU), mixed oxides (MOX), and thorium. On power re-fuelling maintains the reactivity, eliminates the need for re-fuelling outages, and contributes to the availability record of CANDU power plants. The focus of this paper, apart from summarizing some key technical and operating features of the CANDU reactor design, is to demonstrate how the selection of the CANDU technology can contribute to the development of the country’s nuclear industry and economy and allows nucle...

Nuclear Technology, 2018

The increased penetration of intermittent renewable energy technologies such as wind and solar power can strain electric grids, forcing carbon-based and nuclear sources of energy to operate in a load follow mode. For nuclear reactors, load follow operation can be undesirable due to the associated thermal and mechanical stresses placed on the fuel and other reactor components. Various methods of Thermal Energy Storage (TES) can be coupled to nuclear (or renewable) power sources to help absorb grid variability caused by daily load demand changes and renewable intermittency. Two TES techniques are investigated as candidate thermal reservoirs to be used in conjunction with a Small Modular Reactor (SMR): a two-tank sensible heat storage system and a stratified chilled-water storage system. The goal when coupling the two systems to the SMR is to match turbine output and demand and bypass steam to the TES systems to maintain reactor power at approximately 100%. Simulations of Integral Pressurized Water Reactor (IPWR) dynamics are run in a high-fidelity FORTRAN model developed at NCSU. Both TES systems are developed as callable FORTRAN subroutines to model the time-varying behavior associated with different configurations of these systems when connected to the SMR simulator. Simulation results reveal the sensible heat storage system is capable of meeting turbine demand and maintaining reactor power constant, while providing enough steam to power four absorption chillers for chilled-water production and storage. The stored chilled water is used to supplement cooling loads of an adjacent facility.

Science and Technology of Nuclear Installations, 2007

Ignalina NPP is equipped with channel-type boiling-water graphite-moderated reactor RBMK-1500. Results of the level-1 probabilistic safety assessment of the Ignalina NPP have shown that in topography of the risk, the transients with failure of long-term core cooling other than LOCA are the main contributors to the core damage frequency. The total loss of off-site power with a failure to start any diesel generator, that is station blackout, is the event which could lead to the loss of long-term core cooling. Such accident could lead to multiple ruptures of fuel channels with severe consequences and should be analyzed in order to estimate the timing of the key events and the possibilities for accident management. This paper presents the results of the analysis of station blackout at Ignalina NPP. Analysis was performed using thermal-hydraulic state-of-the-art RELAP5/MOD3.2 code. The response of reactor cooling system and the processes in the reactor cavity and its venting system in ca...

Master's Thesis from the year 2012 in the subject Engineering - Industrial Engineering and Management, grade: A, course: M.Tech., language: English, abstract: Importance of BPS can't be ignored particularly in developing countries but feeble effort was seen to improve its power generation cost. An imprecise and outdated frameworks used for bringing change in BPS sector are unable to increase its overall equipment efficiency. The much diversified methodology of Six Sigma has been implemented through a case study which further validates the methodology adopted to tackle the problem formulated, in book ahead. Results achieved during the case, highlights the economical production of backup power by optimizing concerned power-generation parameters of a Cummin's Diesel Genset through strategic application of Six Sigma's DMAIC approach. The book outlines the need for proper energy reform in backup power industry. The DMAIC approach of Six Sigma in BPS sector is too infrequent and next, motivates to reduce backup power cost and its associated expenditures, which are generally ignored.

2011

Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published articles. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book.

Renewable technologies are considered as clean sources of energy and optimal use of these resources minimize environmental impacts, produce minimum secondary wastes and are sustainable based on current and future economic and social societal needs. Energy is a vital input for social and economic development. As a result of the generalization of agricultural, industrial and domestic activities the demand for energy has increased remarkably, especially in emergent countries. This has meant rapid grower in the level of the greenhouse gas emissions and the increase in fuel prices, which are the main driving forces behind efforts to utilize renewable energy more effectively, i.e. energy which comes from natural resources and is also naturally replenished. The nuclear power plant has emerged to be one of the best renewable energy that has been proven in many leading countries. The production of energy through nuclear energy power plant is needed to fulfill the demand, different types of nuclear energy power plant will produce the same product which is energy but must comply with different costs, plans, and suitability based on the country’s environment and climate. But, the most important aspect is on recognizing the best nuclear power plant cooling system that suits the most on one’s country. Different types of the cooling system give different amount of efficiency based on the suitability of the technology with the targeted area’s environment and climate. Thus, knowing the most suitable nuclear power plant cooling system is a must to ensure the efficiency of the production of electrical power at its best. Keywords: Renewable energy, Nuclear energy, Nuclear power plant cooling system.