United States Nuclear Regulatory Commission - Protecting People and the Environment

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. 
Page Last Reviewed/Updated Tuesday, July 23, 2013