Performance Considerations in Power Uprates of Nuclear Power Plants: A Case Study

2005 ◽  
Author(s):  
Komandur S. Sunder Raj
Keyword(s):  
Flow Measurement ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Reactor Power ◽  
Turbine Generator ◽  
Plant Equipment ◽  
The Impact ◽  
Extended Power

This paper examines the impact of power uprates on the performance of nuclear power plants. Since the 1970’s, power companies have been using power uprates to increase the output of their nuclear power plants. The plant systems and components should be capable of accommodating the accompanying increases in flow conditions. The affected components include the turbine-generator, pipes, valves, pumps, heat exchangers, electrical transformer, etc. The Nuclear Regulatory Commission has classified power uprates as falling into three categories: (1) measurement uncertainty recapture power uprates, (2) stretch power uprates and, (3) extended power uprates. Measurement uncertainty recapture power uprates are up to 2% and are achieved by using enhanced techniques for calculating reactor power. This involves the use of state-of-the-art feedwater flow measurement devices to reduce the degree of uncertainty associated with feedwater flow measurement which, in turn, provide for a more accurate calculation of reactor power. Stretch power uprates are typically up to 7% and within the design capacity of the plant. The actual percentage increase in power is plant-specific and depends on the operating margins included in the plant design. Stretch power uprates usually involve changes to instrumentation setpoints, but do not involve major plant modifications. This is especially true for boiling-water reactor plants. In some limited cases where plant equipment is operated at near capacity prior to the power uprate, more substantial changes may be required. Extended power uprates may be up to 20% and, usually require significant modifications to major pieces of plant equipment such as the high pressure turbines, condensate pumps and motors, main generators, and/or transformers. Using a case study, this paper examines the performance considerations involved in power uprates of nuclear power plants. Affected components such as the turbine-generator, moisture separators, reheaters, feedwater heaters and, condensers are discussed. The use of a performance modeling tool in evaluating the impact of power uprates on nuclear plant performance is discussed. The paper provides conclusions and recommendations for ensuring optimal performance in light of power uprates.

scholarly journals Comparison and Evaluation of Domestic and Foreign Radiation Environmental Standards for Nuclear Power Plants

2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The United States ◽  
Discharge System ◽  
Radioactive Effluent ◽  
Effluent Discharge ◽  
The Impact

Abstract With the development of the nuclear energy industry and the increasing demand for environmental protection, the impact of nuclear power plant radiation on the environment has gradually entered the public view. This article combs the nuclear power plant radiation environmental management systems of several countries, takes the domestic and foreign management of radioactive effluent discharge from nuclear power plants as a starting point, analyses and compares the laws and standards related to radioactive effluents from nuclear power plants in France, the United States, China, and South Korea. In this paper, the management improvement of radioactive effluent discharge system of Chinese nuclear power plants has been discussed.

The Impact of Nuclear Power Plants on the Cooling Pond

2021 ◽  
pp. 309-314
Author(s):  
Irma Martyn ◽  
Yaroslav Petrov ◽  
Sergey Stepanov ◽  
Artem Sidorenko
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Cooling Pond ◽  
The Impact

Study on the Impact Limiter Design in Spent Fuel Transfer Cask in Nuclear Power Plants

2020 ◽  
Author(s):  
Yuchen Hao ◽  
Yue Li ◽  
Jinhua Wang ◽  
Bin Wu ◽  
Haitao Wang
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Theoretical Method ◽  
Structure Design ◽  
Design Approach ◽  
Spent Fuel ◽  
Typical Structure ◽  
Explicit Finite Element ◽  
The Impact

Abstract In nuclear power plants, the amount of spent fuel stored on-site is limited. Therefore, it is necessary to be shipped to off-site storage or disposal facilities regularly. The key risk in the transfer of spent fuel involves a release of radiation that could cause harmful effects to people and the environment. Transfer casks with impact limiters on both ends are always employed to ensure safe containment of radioactive materials, which should be verified by the 9 meters drop test onto an unyielding surface according to IAEA SSR-6. In this paper, we focus on the influence of the impact-limiter parameters, including geometry dimensions and mechanical properties, on the results of drop events to achieve an optimized approach for design. The typical structure of impact limiter is bulk energy-absorbed material wrapped by thin stainless-steel shells. Compared to traditional wood, foam has advantages of isotropy and steady quality. In this paper, theoretical and numerical methods are both adopted to investigate the influence of impact limiters during hypothetical accidental conditions for optimizing buffer influence and protecting the internal fuel components. First of all, a series of polyurethane foam is selected according to the theoretical method, because its mechanical property is related to density. Therefore, using explicit finite element method to investigate the influence of parameters of foam in impact limiter. These discrete points from the above result can be utilized to establish damage curves by date fitting. Finally, a design approach for spent fuel transfer cask is summarized, to provide a convenient formula to predict the damage and optimize structure design in drop condition. Furthermore, this design approach can be applied in the multi-module shared system of SNF, which can contain different fuel assemblies.

Canadian Nuclear Safety Commission: Readiness to Regulate SMRs in Canada

2011 ◽  
Author(s):  
S. Herstead ◽  
M. de Vos ◽  
S. Cook
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Safety Analysis ◽  
Reactor Power ◽  
Nuclear Safety ◽  
Regulatory Framework ◽  
Nuclear Industry ◽  
Plant Design ◽  
Regulatory Documents

The success of any new build project is reliant upon all stakeholders — applicants, vendors, contractors and regulatory agencies — being ready to do their part. Over the past several years, the Canadian Nuclear Safety Commission (CNSC) has been working to ensure that it has the appropriate regulatory framework and internal processes in place for the timely and efficient licensing of all types of reactor, regardless of size. This effort has resulted in several new regulatory documents and internal processes including pre-project vendor design reviews. The CNSC’s general nuclear safety objective requires that nuclear facilities be designed and operated in a manner that will protect the health, safety and security of persons and the environment from unreasonable risk, and to implement Canada’s international commitments on the peaceful use of nuclear energy. To achieve this objective, the regulatory approach strikes a balance between pure performance-based regulation and prescriptive-based regulation. By utilizing this approach, CNSC seeks to ensure a regulatory environment exists that encourages innovation within the nuclear industry without compromising the high standards necessary for safety. The CNSC is applying a technology neutral approach as part of its continuing work to update its regulatory framework and achieve clarity of its requirements. A reactor power threshold of approximately 200 MW(th) has been chosen to distinguish between large and small reactors. It is recognized that some Small Modular Reactors (SMRs) will be larger than 200 MW(th), so a graded approach to achieving safety is still possible even though Nuclear Power Plant design and safety requirements will apply. Design requirements for large reactors are established through two main regulatory documents. These are RD-337 Design for New Nuclear Power Plants, and RD-310 Safety Analysis for Nuclear Power Plants. For reactors below 200 MW(th), the CNSC allows additional flexibility in the use of a graded approach to achieving safety in two new regulatory documents: RD-367 Design of Small Reactors and RD-308 Deterministic Safety Analysis for Small Reactors. The CNSC offers a pre-licensing vendor design review as an optional service for reactor facility designs. This review process is intended to provide early identification and resolution of potential regulatory or technical issues in the design process, particularly those that could result in significant changes to the design or analysis. The process aims to increase regulatory certainty and ultimately contribute to public safety. This paper outlines the CNSC’s expectations for applicant and vendor readiness and discusses the process for pre-licensing reviews which allows vendors and applicants to understand their readiness for licensing.

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