United States Nuclear Regulatory Commission - Protecting People and the Environment

IEB 80-08 Examination of Containment Liner Penetration Welds (Generic Letter 80-28)

GL80028                                                  SSINS No. 6820 
                                                         Accession No.: 

                                 UNITED STATES
                         NUCLEAR REGULATORY COMMISSION
                            WASHINGTON, D.C.  20555

                                                 IE Bulletin No. 80-08
                                                 Date:  April 7, 1980
                                                 Page 1 of 2


Description of Circumstances: 

On March 20-23, 1979, an NRC inspection at Nine Mile Point Unit 2, 
identified that certain nondestructive examinations performed on containment 
penetration welds did not satisfy the applicable ASME Boiler and Pressure 
Vessel (B&PV) Code requirements.  The welds in question were the primary 
piping containment penetration fluid head (integral fitting) to outer sleeve 
welds which form a part of the containment pressure boundary.  The 
examinations performed included ultrasonic and surface inspections of the 
outer surface. 

Subsequent to the identification of this code problem at Nine Mile Point 
Unit 2, three welds previously found to be acceptable using ultrasonics were
radiographed and two revealed indications in excess of the code allowable. 
The indications revealed by radiography were slag and lack-of-fusion. 
Preliminary NRC review indicates that the probable reason the indications 
were not detected by ultrasonics was due to masking from signals received 
from the backing bar.  As a result of these findings, a complete 
re-examination program at Nine Mile Point Unit 2 was initiated wherein 10 of 
17 welds previously examined and found to be acceptable using ultrasonics, 
were re-examined by radiography before rework and found to have indications 
exceeding ASME Code allowables. 

Additional information concerning Beaver Valley Unit 2 and North Anna 3 and 
4 has also shown cases of fluid head piping penetration weld defects 
exceeding ASME B&PV Code acceptance criteria when radiographed.  Original 
approved vendor procedures at Beaver Valley Unit 2 did not require 
volumetric examination.  Radiography for information purposes disclosed the 
unacceptable indications at North Anna 3 and 4.  Specification deficiencies 
have also been discovered at Millstone 3 and River Bend where radiography of 
these welds was not required. 

The ASME B&PV Code requires radiography of the subject welds with specified 
exceptions.  The licensees and their architect engineer (Stone and Webster) 
had specified ultrasonics as the volumetric examination method because, in 
their judgement, radiography was impractical for the penetration geometry. 
Radiography was successfully performed at North Anna 3 and 4 prior to the 
identification of this problem and at Beaver Valley 2 and Nine Mile Point 2 
subsequent to NRC inspections.  This experience indicates that radiography 
was meaningful and more practical than UT examination of these penetration 
welds when backing bars are present. 

                                                 IE Bulletin No. 80-08 
                                                 Date:  April 7, 1980
                                                 Page 2 of 2 

Action to be Taken by Licensee: 

For all power reactor facilities with an operating license or a construction

1.    Determine if your facility contains the fluid head design for 
      penetration connections, or other designs with containment boundary 
      butt weld(s) between the penetration sleeve and process piping as 
      illustrated in Figure NE 1120-1, Winter 1975 Addenda to the 1974 and 
      later editions of the ASME B&PV Code. 

2.    If an affirmative answer is reached for Item 1, determine the 

      a.    Applicability of the ASME Code including year and addenda and/or
            Regulatory Guide 1.19, 

      b.    Type of nondestructive examinations performed during 

      c.    Type of weld joint (including pipe material and size) and 
            whether or not backing bars were used, 

      d.    Results of construction nondestructive examinations, i.e., if 
            repairs were required, this should be identified including 
            extent of repairs and description of defects encountered during 
            repair, if known. 

3.    For those facilities committed during construction to perform 
      volumetric examination of such penetrations through SAR commitments 
      which have not performed radiography, justify not performing 
      radiography or submit plans and schedules for performing radiographic 

Within 90 days of the date of this Bulletin, facilities with an operating 
license or a construction permit shall submit the information requested in 
Items 1, 2, and 3 of this Bulletin. 

Reports shall be submitted to the Regional Director with a copy to the 
Director, Division of Reactor Construction Inspection, Washington, D.C. 

Approved by GAO, B180225 (R0072); clearance expires 7-31-80.  Approval was 
given under a blanket clearance specifically for identified generic 

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