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Bulletin 79-14: Supplement 2, Seismic Analyses For As-Built Safety-Related Piping Systems
SSINS: 6820 Accession No: 7908220109 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 September 7, 1979 IE Bulletin No. 79-14 Supplement 2 SEISMIC ANALYSIS FOR AS-BUILT SAFETY-RELATED PIPING SYSTEMS Description of Circumstances: IE Bulletin No. 79-14 was issued on July 2, revised on July 18, and first supplemented on August 15, 1979. The bulletin requested licensees to take certain actions to verify that seismic analyses are applicable to as-built plants. Supplement 2 provides the following additional guidance with regard to implementation of the bulletin requirements: Nonconformances One way of satisfying the requirements of the bulletin is to inspect safety- related piping systems against the specific revisions of drawings which were used as input to the seismic analysis. Some architect-engineers (A-E) however, are recommending that their customers inspect these systems against the latest revisions of the drawings and mark them as necessary to define the as-built configuration of the systems. These drawings are then returned to the AE's offices for comparison by the analyst to the seismic analysis input. For licensees taking this approach, the seismic analyst will be the person, who will identify nonconformances. The first supplement to the bulletin provided guidance with regard to evaluation of nonconformances. That guidance is appropriate for licensees inspecting against later drawings. The licensee should assure that he is promptly notified when the AE identifies a nonconformance, that the initial engineering judgment is completed in two days and that the analytical engineering evaluation is completed in 30 days. If either the engineering judgement or the analytical engineering evaluation indicates that system operability is in jeopardy, the licensee is expected to meet the applicable technical specification action statement. Visual Approximations Some licensees are visually estimating pipe lengths and other inspection elements, and have not documented which data have been obtained in that way. Visual estimation of dimensions is not encouraged for most measurements, however, where visual estimates are used, the accuracy of estimation must be within tolerance requirements. Further, in documenting the data, the licensee must specifically identify those data that were visually estimated. . IE Bulletin No. 79-14, Supplement 2 September 7, 1979 Page 2 of 2 Thermal Insulation In many areas, thermal insulation interferes with inspection of pipe support details, i.e. attachment welds, saddles, support configuration, etc. In some areas, the presence of thermal insulation may result in unacceptably large uncertainties for determination of the location of pipe supports. Where thermal insulation obstructs inspection of support details, the insulation should be removed for inspection of a minimum of 10% of the obstructed pipe supports in both Item 2 and 3 inspections. In the Item 3 response, the licensee should include a schedule for inspecting the remaining supports. Where necessary to determine the location of pipe supports to an accuracy within design tolerances, thermal insulation must be removed. Clearances For exposed attachments and penetrations, licensees are expected to measure or estimate clearances between piping and supports, integral piping attachments (e.g. lugs and gussets) and supports, and piping and penetrations. Licensees are not expected to do any disassembly to measure clearances. Loose Bolts Loose anchor bolts are not covered by this bulletin, but are covered by IE Bulletin No. 79-02. Any loose anchor bolts identified during actions taken for this bulletin should be dispositioned under the requirements of Bulletin No. 79-02. Other loose bolts are to be treated as nonconformances if they invalidate the seismic analysis; however, torquing of bolts is not required. Difficult Access Areas where inspections are required by the Bulletin but are considered impractical even with the reactor shutdown, should be addressed on a case by case basis. Information concerning the burden of performing the inspection and the safety consequence of not performing the inspection should be documented by the licensee and forwarded for staff review. Schedule The schedule for the action and reporting requirements given in the Bulletin as originally issued remains unchanged.
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