Reactor Pressure Vessel Head and Vessel Head Penetration Nozzle Inspection Programs; Issue

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Notice of issuance.

SUMMARY:

The Nuclear Regulatory Commission (NRC) has issued Bulletin (BL) 2002-02 to all holders of operating licenses for pressurized-water reactors (PWRs), except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel, and all holders of operating licenses for boiling-water reactors for information. It concerns the recent discoveries of cracked and leaking Alloy 600 vessel head penetration (VHP) nozzles at several PWRs and the reactor pressure vessel (RPV) head degradation at Davis-Besse Nuclear Power Station. These discoveries have raised concerns about the adequacy of current inspection programs that rely on visual examinations as the primary inspection method to ensure RPV head and VHP structural integrity. Specifically, the staff is concerned that the inspection methods and frequencies (i.e., inspection intervals) of current inspection programs may not be sufficient. Based on experience and information currently available, it may be necessary for inspection programs that rely on visual examinations to be supplemented with additional measures (e.g., volumetric and surface examinations) to demonstrate compliance with applicable regulations.

The issuance of this bulletin is the first step in a multi-step approach to address concerns about the adequacy of inspection requirements and programs for RPV heads and VHP nozzles. The other steps are: review the bulletin responses and determine what further regulatory actions are needed (e.g., revision to 10 CFR 50.55a), review the Electric Power Research Institute's Material Reliability Program's (MRP's) proposed inspection program once an applicable technical basis is provided, encourage the revision of American Society of Mechanical Engineers (ASME) Code inspection requirements, and, if acceptable, incorporate the revised ASME Code requirements into NRC regulations.

The purpose of the bulletin is to (1) advise PWR addressees that visual examinations, as a primary inspection method for the RPV head and VHP nozzles, may need to be supplemented with additional measures (e.g., volumetric and surface examinations) to demonstrate compliance with applicable regulations, (2) advise PWR addressees that inspection methods and frequencies to demonstrate compliance with applicable regulations should be demonstrated to be reliable and effective, (3) request information from all PWR addressees concerning their RPV head and VHP nozzle inspection programs to ensure compliance with applicable regulatory requirements, and (4) require all addressees to provide written responses to the bulletin related to their inspection program plans.

DATES:

The bulletin was issued on August 9, 2002.

ADDRESSES:

Not applicable.

FOR FURTHER INFORMATION CONTACT:

Allen L. Hiser, at 301-415-1034, Timothy K. Steingass, at 301-415-3312, Michael L. Marshall, at 301-415-2734, or Steven D. Bloom, at 301-415-1313.

SUPPLEMENTARY INFORMATION:

Bulletin 2002-02 may be examined and/or copied for a fee at the NRC's Public Document Room, located at One White Flint North, 11555 Rockville Pike (first floor), Rockville, Maryland, and is accessible electronically from the Agencywide Documents Access and Management Systems (ADAMS) Public Electronic Reading Room on the Internet at the NRC Web site, http://www.nrc.gov/reading-rm/adams.html. The ADAMS Accession No. for the bulletin is ML022200494.

If you do not have access to ADAMS or if there are problems in accessing documents located in ADAMS, contact the NRC Public Document Room (PDR) Reference staff at 301-415-4737 or 1-800-397-4209, or by e-mail to pdr@nrc.gov.