Identification and Resolution of Piping Analysis Activities for Extended Power Uprates at Nuclear Plants

Author(s):  
Dilip Bhavnani

Recent experience has shown that many utilities have installed new feedwater flow measurement instrumentation, which is designed with new, proven technology that more accurately monitors feedwater flow and therefore, allows for improved thermal power level calculations. As a result of this new approach, many utilities have been able to extend limited power upgrades to the tune of 1.4%, and yet with no noticeable additional environmental impact. These electric power increases are generally attributable to the large design margins included in the original nuclear power plant designs and in addition, to the technological advances that have been made to the nuclear industry. Power increases are now carried out by several nuclear utilities in the United States with the NRC’s concurrence. Current nuclear power plants are providing cheap, reliable and affordable electricity to help meet current energy growing demands. As a result of this, power uprate increases are encouraged. Current economic conditions strongly favor power uprates and plant life extensions. In the early 1990s, a limited power uprate program was initiated, but due to complex design reviews, this was not steadfastedly recommended during this time period. Nuclear Steam Supply Systems (NSSS) vendors performed a key role in this nuclear power uprate program. This paper discusses structural and piping qualification review required to achieve these power uprate programs, currently being performed by nuclear utilities in the United States.

Author(s):  
Hitoshi Ohata ◽  
Toshikazu Nishibata ◽  
Tetsuya Onose

Reactor thermal power uprate (Power uprate) of operating light water reactors has long successful experiences in many nuclear power plants in the United States of America and European countries since late 1970’s. And it will be also introduced in Japan soon. This paper mainly describes the outline of the attempt of five-percent reactor thermal power uprate of Tokai No.2 Nuclear Power Station (Tokai-2) operated by the Japan Atomic Power Company (JAPC). It will be the leading case in Japan. Tokai-2 is GE type Boiling Water Reactor (BWR) of 1100 MW licensed electric power output and it commenced commercial operation in November 28, 1978. Power uprate is an effective approach for increasing electric power output. And it is recognized as one of the measures for effective and efficient use of existing Japanese operating nuclear power plants. It can contribute to inexpensive and stable electric power supply increase. Especially “Stretch Power Uprate (SPU)” requires only minor equipment modification or component replacement. It is also a countermeasure against global warming. Therefore it is a common theme to be accomplished in the near future for both Japanese electric power companies and government. JAPC started feasibility studies on power uprate in 2003. And in 2007, JAPC established a plan to achieve five-percent power uprate in Tokai-2 and announced this project to the public. This is a leading attempt in the Japanese electric power companies and it is the first case under the current Japanese regulatory requirements. In this plan, JAPC reflected lessons learned from preceding nuclear power plants in the United States and European countries, and tried to make most use of the performance of existing systems and components in Tokai-2 which have been periodically or timely renewed by utilizing more reliable and efficient design. JAPC plans to submit application documents to amend current License for Reactor Establishment Permit shortly. It will contain a complete set of revised safety analysis results based on the uprated reactor thermal power condition. Successful introduction of Tokai-2 power uprate will contribute to the establishment of regulatory process for power uprate in Japan and following attempts by other Japanese electric power companies.


Author(s):  
Garry G. Young ◽  
Mark A. Rinckel

License renewal of operating nuclear power plants in the United States has become one of the most successful nuclear industry activities in the past few years. It is anticipated that over 90% of the 103 operating nuclear power plants in the United States will pursue license renewal and seek an additional 20 years of operation. Some plants may pursue operation to 80 years or longer since the license renewal rule does not limit the operating life of a nuclear power plant. The requirements for renewing the operating license of a nuclear reactor in the United States are contained in Nuclear Regulatory Commission (NRC) Regulation 10 CFR Part 54, which addresses general, technical, technical specification, and environmental requirements. The most labor intensive element of the requirements are the technical requirements, which include addressing an integrated plant assessment (IPA) and time limited aging analyses (TLAA). The cost of performing the needed reviews and obtaining a renewed license ranges between $10M to $15M. The license renewal rule focuses on aging of passive long-lived components and aging management programs that manage those structures and components. The aging management programs credited to manage aging include both existing programs (e.g., ASME Section XI) and a few new programs (e.g., Reactor Vessel Internals Aging Management Program). Commitments to aging management programs for license renewal may be implemented and tracked through a comprehensive plant life management (PLIM) program. PLIM is the process to integrated equipment aging management with other plant activities to maximize plant value. PLIM can save the operating plant a significant amount of money by effectively planning and implementing component refurbishment and replacement. The ultimate decision to seek license renewal and continue operation is based on PLIM, which considers aging, safety, and economics.


Author(s):  
Ronald C. Lippy

The nuclear industry is preparing for the licensing and construction of new nuclear power plants in the United States. Several new designs have been developed and approved, including the “traditional” reactor designs, the passive safe shutdown designs and the small modular reactors (SMRs). The American Society of Mechanical Engineers (ASME) provides specific Codes used to perform preservice inspection/testing and inservice inspection/testing for many of the components used in the new reactor designs. The U.S. Nuclear Regulatory Commission (NRC) reviews information provided by applicants related to inservice testing (IST) programs for Design Certifications and Combined Licenses (COLs) under Part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” in Title 10 of the Code of Federal Regulations (10 CFR Part 52) (Reference 1). The 2012 Edition of the ASME OM Code defines a post-2000 plant as a nuclear power plant that was issued (or will be issued) its construction permit, or combined license for construction and operation, by the applicable regulatory authority on or following January 1, 2000. The New Reactors OM Code (NROMC) Task Group (TG) of the ASME Code for Operation and Maintenance of Nuclear Power Plants (NROMC TG) is assigned the task of ensuring that the preservice testing (PST) and IST provisions in the ASME OM Code to address pumps, valves, and dynamic restraints (snubbers) in post-2000 nuclear power plants are adequate to provide reasonable assurance that the components will operate as needed when called upon. Currently, the NROMC TG is preparing proposed guidance for the treatment of active pumps, valves, and dynamic restraints with high safety significance in non-safety systems in passive post-2000 reactors including SMRs.


Author(s):  
Steven A. Arndt

Over the past 20 years, the nuclear power industry in the United States (U.S.) has been slowly replacing old, obsolete, and difficult-to-maintain analog technology for its nuclear power plant protection, control, and instrumentation systems with digital systems. The advantages of digital technology, including more accurate and stable measurements and the ability to improve diagnostics capability and system reliability, have led to an ever increasing move to complete these upgrades. Because of the difficulties with establishing digital systems safety based on analysis or tests, the safety demonstration for these systems relies heavily on establishing the quality of the design and development of the hardware and software. In the United States, the U.S. Nuclear Regulatory Commission (NRC) has established detailed guidelines for establishing and documenting an appropriate safety demonstration for digital systems in NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition,” Chapter 7, “Instrumentation and Controls,” Revision 5, issued March 2007 [1], and in a number of regulatory guides and interim staff guidance documents. However, despite the fact that the United States has a well-defined review process, a number of significant challenges associated with the design, licensing, and implementation of upgrades to digital systems for U.S. plants have emerged. Among these challenges have been problems with the quality of the systems and the supporting software verification and validation (V&V) processes, challenges with determining the optimum balance between the enhanced capabilities for the new systems and the desire to maintain system simplicity, challenges with cyber security, and challenges with developing the information needed to support the review of new systems for regulatory compliance.


2020 ◽  
Vol 15 (28) ◽  
pp. 344-375
Author(s):  
Anita Paulovics

This paper is about the legal regulation of the extension of the operation time of nuclear power plants.  In Hungary the most important document in this respect has been the National Energy Strategy analyzed in the paper. In Hungary, the legal regulation of the extension of the time limit of the operation-permit of nuclear power plants is modelled on that of the United States. For this reason, the paper examines the rules in force in the USA on the extension of the operation time.  It could be of interest for several European countries considering to extend the operation time of their nuclear power plants.


2009 ◽  
Vol 51 (4) ◽  
pp. 896-926 ◽  
Author(s):  
Gabrielle Hecht

What is Africa's place in the nuclear world? In 1995, a U.S. government report on nuclear proliferation did not mark Gabon, Niger, or Namibia as having any “nuclear activities.” Yet these same nations accounted for over 25 percent of world uranium production that year, and helped fuel nuclear power plants in Europe, the United States, and Japan. Experts had long noted that workers in uranium mines were “exposed to higher amounts of internal radiation than … workers in any other segment of the nuclear energy industry.” What, then, does it mean for a workplace, a technology, or a nation to be “nuclear?” What is at stake in that label, and how do such stakes vary by time and place?


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