License Renewal Demonstration Project

Author(s):  
Barry J. Elliot ◽  
Jerry Dozier

Generic Aging Lessons Learned (GALL) report, License Renewal Standard Review Plan (SRP-LR), and regulatory guide were issued by the United States Nuclear Regulatory Commission (NRC) in June 2001. The intent of these documents was to provide the technical and process basis that will lead to a more effective, efficient and predictable license renewal process for industry and the NRC. The GALL report provides the aging effects on components and structures, identifies the relevant existing plant programs, and evaluates the program attributes to manage aging effects for License Renewal. The GALL report also identifies when existing plant programs would require further evaluation for License Renewal. The SRP-LR allows the applicant to reference the GALL report to demonstrate that the programs at the applicant’s facility correspond to those reviewed and approved in the GALL report. Programs that correspond to those in the GALL report will not need further detailed review by the staff. Implementation of the aging management program are verified as part of the license renewal inspection program. The GALL report identifies one acceptable way of demonstrating that components and structures have adequate aging management programs. However, applicants may propose alternatives to the programs identified in GALL. During the license renewal review, the NRC primarily focuses on areas where existing programs should be augmented or new programs developed for License Renewal. This paper will provide an overview of these documents and some of the lessons learned during a demonstration project in the application of the new guidance. This topic will be of interest to the U.S. participants considering License Renewal and desiring to know state-of-the-art information about License Renewal in the United States.

Author(s):  
V. N. Shah ◽  
Y. Y. Liu

The paper reviews the existing aging management programs (AMPs) for the reactor coolant system (RCS) components in pressurized water reactors (PWRs), including the reactor pressure vessel and internals, the reactor coolant system and connected lines, pressurizer, reactor coolant pumps, valves, and steam generators. These programs have been evaluated in the U.S. Nuclear Regulatory Commission (NRC) report Generic Aging Lessons Learned (GALL), NUREG-1801, for their use in the license renewal process. These AMPs include both generic and plant-specific programs. The generic AMPs are acceptable for managing aging effects during an extended period of operation and do not require further evaluation; the plant-specific AMPs require further evaluation. The use of the GALL report should facilitate both preparation of a license renewal application and timely and uniform review by the NRC staff.


Author(s):  
Mansoor H. Sanwarwalla

One of the requirements for license renewal for US nuclear plants stated in the United States Nuclear Regulatory Commission (USNRC) regulations in the License Renewal Rule (LRR) 10CFR Part 54 (Ref. 1) is the identification and updating of Time-Limited Aging Analyses (TLAA). During the design phase for a plant, certain assumptions about the length of time the plant would be operated were made and incorporated into design calculations for several of the plant’s systems, structures and components (SSCs). Examples of TLAAs are analyses of metal fatigue, environmental qualification (EQ) of electric equipment, etc. For a renewed license, these calculations have to be reviewed to verify that they remain valid for the period of extended operation. However, the LRR does allow TLAA-associated aging effects to be managed by an aging management program. This paper discusses the USNRC regulatory requirements for TLAAs and the industry’s response for addressing the TLAAs. It also discusses the issues regarding the generic set of TLAAs that have been identified by the NRC in NUREG-1801 (Ref. 2), and how these have been addressed by all the plants that have received their renewed license. The paper also identifies certain plant specific TLAAs.


Author(s):  
Terry L. Dickson ◽  
Shah N. Malik ◽  
Mark T. Kirk ◽  
Deborah A. Jackson

The current federal regulations to ensure that nuclear reactor pressure vessels (RPVs) maintain their structural integrity when subjected to transients such as pressurized thermal shock (PTS) events were derived from computational models that were developed in the early to mid 1980s. Since that time, there have been advancements in relevant technologies associated with the physics of PTS events that impact RPV integrity assessment. Preliminary studies performed in 1999 suggested that application of the improved technology could reduce the conservatism in the current regulations while continuing to provide reasonable assurance of adequate protection to public health and safety. A relaxation of PTS regulations could have profound implications for plant license extension considerations. Based on the above, in 1999, the United States Nuclear Regulatory Commission (USNRC) initiated a comprehensive project, with the nuclear power industry as a participant, to re-evaluate the current PTS regulations within the framework established by modern probabilistic risk assessment (PRA) techniques. During the last three years, improved computational models have evolved through interactions between experts in the relevant disciplines of thermal hydraulics, PRA, human reliability analysis (HRA), materials embrittlement effects on fracture toughness (crack initiation and arrest), fracture mechanics methodology, and fabrication-induced flaw characterization. These experts were from the NRC staff, their contractors, and representatives from the nuclear industry. These improved models have now been implemented into the FAVOR (Fracture Analysis of Vessels: Oak Ridge) computer code, which is an applications tool for performing risk-informed structural integrity evaluations of embrittled RPVs subjected to transient thermal-hydraulic loading conditions. The baseline version of FAVOR (version 1.0) was released in October 2001. The updated risk-informed computational methodology in the FAVOR code is currently being applied to selected domestic commercial pressurized water reactors to evaluate the adequacy of the current regulations and to determine whether a technical basis can be established to support a relaxation of the current regulations. This paper provides a status report on the application of the updated computational methodology to a commercial pressurized water reactor (PWR) and discusses the results and interpretation of those results. It is anticipated that this re-evaluation effort will be completed in 2002.


Author(s):  
John Minichiello ◽  
Ernest B. Branch ◽  
Timothy M. Adams ◽  
Yasuhide Asada ◽  
Richard W. Barnes

The new rules for seismic piping design in Section III that were developed and included in the requirements in 1994 Addenda of the ASME Boiler and Pressure Vessel Code (B&PV Code) generated considerable discussion within the industry and from the United States Nuclear Regulatory Commission, (USNRC). The USNRC initiated a review of the results of the previous EPRI/NRC experimental program and the Japanese industry started its own experimental program. To accommodate and address developments resulting from these efforts, the ASME, B&PV Code established a Special Working Group (SWG) to continue the review and study of the questions and information generated. This paper reports on the efforts of this SWG which resulted in refinements of the revised rules. These refinements have been accepted for inclusion in Section III of the ASME, B&PV Code.


Author(s):  
Terry Dickson ◽  
Shengjun Yin ◽  
Mark Kirk ◽  
Hsuing-Wei Chou

As a result of a multi-year, multi-disciplinary effort on the part of the United States Nuclear Regulatory Commission (USNRC), its contractors, and the nuclear industry, a technical basis has been established to support a risk-informed revision to pressurized thermal shock (PTS) regulations originally promulgated in the mid-1980s. The revised regulations provide alternative (optional) reference-temperature (RT)-based screening criteria, which is codified in 10 CFR 50.61(a). How the revised screening criteria were determined from the results of the probabilistic fracture mechanics (PFM) analyses will be discussed in this paper.


Author(s):  
David Alley

This paper provides a historical perspective on the need for, and development of, buried and underground piping tanks programs at nuclear power plants. Nuclear power plant license renewal activities, Nuclear Regulatory Commission Buried Piping Action Plan, and the rationale for addressing the issue of buried pipe through an industry initiative as opposed to regulation are discussed. The paper also addresses current NRC activities including the results of Nuclear Regulatory Commission inspections of buried piping programs at nuclear power plants as well as Nuclear Regulatory Commission involvement in industry and standards development organizations. Finally, the paper outlines the Nuclear Regulatory Commission’s future plans concerning the issue of buried piping at US nuclear power plants.


Author(s):  
William Greenman ◽  
Kimberly Cole

Abstract In the United States, mixed-waste is typically defined as waste that contains both radioactive constituents and non-radioactive constituents that pose a threat to human health or the environment (hazardous waste). Prior to 1986 the U.S. Nuclear Regulatory Commission (NRC) had sole regulatory authority over mixed-waste because of its radioactive constituents. In 1986, however, the U.S. Environmental Protections Agency (EPA) was granted regulatory authority over the hazardous constituents in mixed-waste; and, a system of dual regulation was created. Dual regulation of mixed-waste by the EPA and the NRC has caused significant problems for the regulated community. The burden of dual regulation has contributed to the slow development of treatment technologies, and to the overall lack of treatment capacity available to U.S generators of mixed-waste. This paper reviews the requirements that the EPA and the NRC mandate with regard to mixed-waste generation, treatment and disposal; and it explores technical impacts of those requirements as they relate to generators, treatment facilities and the public.


Author(s):  
William F. Weitze ◽  
Matthew C. Walter ◽  
Keith R. Evon

As part of the process of renewing the operating license for an additional 20 years after the original 40-year design life, nuclear plant owners in the United States (US) are required to show that they are managing the effects of aging of systems, structures, and components. US Nuclear Regulatory Commission (NRC) report NUREG-1801, the “Generic Aging Lessons Learned (GALL) Report,” identifies acceptable aging management programs, including programs for fatigue and cyclic operation. This includes fatigue usage analyses that account for reduced fatigue life for components in a reactor water environment. Earlier revisions of the GALL report required plants to perform environmentally-assisted fatigue (EAF) analyses using the rules in reports NUREG/CR-6583 (for carbon and low alloy steels) and NUREG/CR-5704 (for austenitic stainless steels), which were developed in 1998 and 1999, respectively. However, GALL Revision 2, issued in December 2010, requires that the rules in NUREG/CR-6909, issued in 2007, be used for nickel alloy materials, and allows it to be used for carbon, low-alloy and stainless steels as an alternative to those in the previous reports. This paper presents an application of the NUREG/CR-6909 rules, and makes several observations about the differences between using the newer and older rules. The analyses presented were performed for a sample set of boiling water reactor (BWR) locations.


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