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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

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.

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The staff uses the RVID to review information submitted by licensees. The reviewers note applicable data and information revisions before updating the RVID.

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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.

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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.

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Related Information

  • Regulatory Guide (RG) 1.99, Revision 2, "Radiation Embrittlement of Reactor Vessel Materials" gives the programming logic used for calculations in the RVID
  • Generic Letter (GL) 92-01, Revision 1, Supplement 1. The majority of the current data inputs to the RVID were submitted in response to this GL.
  • Appendix G to 10 CFR Part 50 - Fracture Toughness Requirements
  • Appendix H to 10 CFR Part 50 - Reactor Vessel Material Surveillance Program Requirements (10 CFR 50.61)
  • 10 CFR 50.60 - Acceptance Criteria for Fracture Prevention Measures for LIghtwater Nuclear Power Reactors for Normal Operation
  • 10 CFR 50.61 - Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events
  • Generic Letter (GL) 88-11, "NRC Position on Radiation Embrittlement of Reactor Vessel Materials and Its Impact on Plant Operations"

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Friday, June 01, 2007