Reactor Vessel Integrity
Vessels that house reactors are bombarded with nuclear materials and must be constructed of materials that can withstand exposure to neutron irradiation and heat (the thermal environment) that occurs during fission. Licensees are required to establish surveillance programs for their reactor vessels that meet certain standards.
During years of reactor operational experience licensees have sometimes experienced problems maintaining optimum reactor vessel integrity. From this experience, NRC has accumulated information about the integrity of reactor vessels and, in 1992, developed a reactor vessel integrity database (RVID).
On this page:
- Source of the Information
- Purpose
- Access to the Data
- Last Update
- Related Reactor Materials Embrittlement Data
Source of the Information
NRC developed the RVID following staff review of licensee responses to Generic Letter (GL) 92-01, Revision 1, "Reactor Vessel Structural Integrity."
The database reflects the current status of reactor vessel integrity for each commercial nuclear power plant in the United States. The data are consolidated in a convenient and accessible manner. The RVID summarizes the properties of the reactor vessel beltline materials for each plant.
Purpose
The staff uses the RVID to review information submitted by licensees. The reviewers note applicable data and information revisions before updating the RVID.
Access to the Data
Staff. Updates to the RVID are internal until the staff determines that sufficient amounts of new surveillance data, chemistry data, or fluence evaluations warrant a new release to the public. The application version and "last data update" date are designated for each release. The RVID is a FoxPro application that executes on Microsoft Windows computers. Only a few NRC staff members may update the database.
Public. For ease of distribution to licensees and the public, the database is provided as four downloads called virtual diskettes (each download will fit onto a diskette), which are available via the RVID page.
Users of the publicly distributed database application, however, cannot change or update RVID data.
If a licensee's data or information does not agree with the data in the RVID, the licensee can submit letters to the NRC that outline the discrepancies.
Last Update
The updated RVID virtual diskettes were last released for public distribution in July 2000. The NRC staff continues to note data and information revisions for internal database updates in preparing for the future releases.
Related Reactor 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 vessel. This irradiation embrittles the steel, making it less tough and, therefore, less capable of maintaining 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.
Available in open format (Microsoft Excel), this Reactor Materials Embrittlement Dataset provides access to information on surveillance capsule reports, which include reactor materials embrittlement data from the Nation’s fleet of operating nuclear power reactors. Specifically, this dataset lists each plant name and reactor type, designer, and manufacturer. It also states the plant’s license term, the date on which the operating license will expire, and whether the plant was licensed to operate as of January 1, 2011. In addition, the dataset provides the PDF filename for the plant’s surveillance capsule report, along with the report date and identification of the specific surveillance capsule. The related Data Dictionary explains each field in the dataset and provides instructions for accessing the surveillance capsule reports.
