United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 85-33: Undersized Nozzle-to-Shell Welded Joints in Tanks and Heat Exchangers Constructed Under the Rules of the Asme Boiler and Pressure Vessel Code

                                                         SSINS No.:  6835
                                                            IN 85-33 

                                UNITED STATES
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                            WASHINGTON, DC 20555 

                               April 22, 1985 

Information Notice No. 85-33:  UNDERSIZED NOZZLE-TO-SHELL WELDED JOINTS 
                                  IN TANKS AND HEAT EXCHANGERS CONSTRUCTED 
                                  UNDER THE RULES OF THE ASME BOILER AND 
                                  PRESSURE VESSEL CODE 

Addressees: 

All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP). 

Purpose: 

This information notice is to provide addressees with information pertaining
to undersized nozzle-to-shell welded joints in tanks and heat exchangers 
constructed under the rules of the ASME Boiler and Pressure Vessel Code. 
These observations were made at several nuclear power plant sites during NRC
Construction Appraisal Team (CAT) inspections. It is expected that 
recipients will review the information for specific and generic 
applicability to their facilities and consider appropriate actions. However, 
the suggestions contained in this notice do not constitute NRC requirements; 
therefore, no specification or response is required. 

Description of Circumstances: 

During the CAT inspections conducted at the River Bend, Shearon Harris, and 
Braidwood nuclear power projects, the NRC identified undersized nozzle-to-
shell welded joints (ASME Category D joints) in tanks and heat exchangers 
manufactured by various vendors. Specifically, four main steam isolation 
valve air accumulator tanks were found to have undersized nozzle-to-shell 
joints at the River Bend plant; seven tanks were found to have undersized 
nozzle-to-shell weld reinforcements at the Shearon Harris Station; eight 
tanks and two heat exchangers were found to have undersized nozzle-to-shell 
weld reinforcements at Braidwood Station. These tanks and heat exchangers 
were Code stamped and certified as being constructed in accordance with the 
requirements of the ASME Code. The ASME Code, Section III (NX-3352.4) 
requires that nozzle-to-shell welded joints have reinforcement (tc) of 0.7tn 
or 1/4 inch, whichever is less, where tn is the thickness of the penetrating 
art. Some of the inspected welded joints did not have the minimum weld 
reinforcement (tc) required by the Code. Other joints had the minimum weld 
reinforcement (tc) required by the Code, but were found to be undersized 
with respect to the sizes specified on the applicable construction drawings.

.

                                                            IN 85-33 
                                                            April 22, 1985 
                                                            Page 2 of 2 

Discussion: 

The NRC inspection program examines only a small sample of construction 
activities. The NRC CAT inspections conducted at nuclear power plant 
construction sites have indicated that tanks and heat exchangers have been 
installed at these facilities that do not have the weld reinforcements 
required by the ASME Code or do not follow the specifications of the 
construction drawings. As a result of these findings, the licensee of each 
affected facility has initiated reinspection actions to find out whether the 
installed components meet the design rules of NX-3352.4 of Section III of 
the ASME Code for Category D joints. Components that meet the design rules 
of the ASME Code but do not meet the weld reinforcement size specified on 
the applicable design drawings are being evaluated for adequacy. 

No specific action or written response is required by this information 
notice. If you have any questions about this matter, please contact the 
Regional Administrator of the appropriate NRC regional office or this 
office. 



                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:   G. B. Georgiev, IE 
                     (301) 492-9674 

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