Reactor pressure vessels, which contain the nuclear fuel that powers the reactor core in nuclear power plants, are made of cylindrical shell courses with a welded hemispherical bottom head and a removable hemispherical upper head. The shell courses are fabricated from thick steel plates or ring forgings that are welded together. When the reactor is operated, neutron radiation from the reactor core causes embrittlement of the reactor vessel. Embrittlement refers to a decrease in the fracture toughness of reactor vessel materials and affects the vessel materials in the vicinity of the reactor fuel, referred to as the vessel’s "beltline."
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Source of the Information
As a result of its review of licensee responses to Generic Letter 92-10, the NRC staff developed a comprehensive database to compile and record summaries of the material properties for the reactor vessel beltline materials for each plant. This database is known as the reactor vessel integrity database (RVID). The RVID contains data up to approximately the year 2000 and fracture toughness projections to the end of the original 40-year operating license.
Purpose
The staff uses the RVID to efficiently access plant-specific reactor vessel data and information submitted through approximately the year 2000, pertaining to reactor vessel integrity.
Access to the Data
RVID is available to external stakeholders such as licensees and the general public. For ease of distribution, the database is provided as a Microsoft Excel spreadsheet via the RVID page.
Last Update
The RVID data was last updated in July 2000. There are no current plans to update RVID.
Updated values of material properties for the reactor vessel beltline are provided in staff safety evaluations for Initial License Renewal and Subsequent License Renewal Applications, and in other licensing documents that can be found in the Agencywide Documents Access and Management System (ADAMS). These documents provide fracture toughness projections to the end of a 60 or 80-year operating license. A list of plants that have gone through Initial or Subsequent License Renewal, links to the applications, and staff safety evaluations can be found on the status pages for initial license renewal, subsequent license renewal, and through the public NRC ADAMS website.
Related Reactor Vessel Materials Embrittlement Data
Consistent with our Open Government Plan, the NRC has issued a high-value dataset (with accompanying data dictionary) to expand the public's knowledge about the agency's oversight of operating reactor facilities, as it relates to embrittlement of reactor pressure vessel materials. Irradiation embrittlement is a phenomenon that occurs as a consequence of reactor operation when neutrons from the nuclear fuel irradiate the thick steel plates and welds used to construct the reactor vessel. This irradiation embrittles the steel, making it less tough and, therefore, can compromise its structural integrity in the presence of flaws that may exist following fabrication. (For additional detail, see the Fact Sheet on Reactor Pressure Vessel Issues). The NRC obtains information on irradiation embrittlement from surveillance capsule reports obtained through the Reactor Vessel Material Surveillance Program conducted under Appendix H to Title 10, Part 50, of the Code of Federal Regulations (10 CFR Part 50). Information from these surveillance capsule reports is summarized in the RVID, along with information from other sources.
The NRC has developed the Reactor Embrittlement Archive Project (REAP) to present archival sources of information concerning the effects of neutron radiation on the properties of reactor vessel steels for surveillance capsule materials. This database contains information on Charpy V-notch impact energy, Charpy lateral expansion, Charpy percentage shear facture area, tensile properties, chemistry composition, applied heat treatment procedures, exposure temperatures, and neutron flux and fluence. REAP summarizes data from surveillance capsule reports. The public can request access to the REAP Database.
Page Last Reviewed/Updated Friday, September 13, 2024