NRC PUBLIC MEETING MARCH 13 TO DISCUSS 

POTENTIAL PRESSURIZED WATER REACTOR WELD ISSUES 

 The Nuclear Regulatory Commission staff will meet with officials of eight U.S. 

commercial reactors Thursday, March 13, in Rockville, Md., to discuss emerging information 

regarding certain welds in pressurized water reactors (PWR). 

 “We’re looking at welds on the pressurizer, a vessel that creates and maintains a small 

amount of steam to keep a PWR’s coolant system at the proper pressure,” said James Wiggins, 

Acting Director of the NRC’s Office of Nuclear Reactor Regulation. “Our research activities 

recently gave us new information that raises some questions about whether eight plants can 

continue to run until their next scheduled shutdown before inspecting and possibly repairing 

these welds. New data from inspections of similar welds indicates those plants may need to 

take action sooner.” 

 The meeting will be held from 9 – 11 a.m. Thursday in the Commission Conference 

Room of the NRC’s One White Flint building, 11555 Rockville Pike in Rockville. NRC staff 

and plant executives will discuss information gathered during examination of a pressurizer 

formerly used at the St. Lucie plant in Florida. Potential weld flaws in that pressurizer raised 

questions about computer analyses used to justify extending a weld inspection deadline for 

eight facilities: 

• Braidwood Unit 2, near Joliet, Ill.; 

• Comanche Peak Unit 2, near Glen Rose, Texas; 

• Palo Verde Unit 2, near Phoenix, Ariz.; 

• Seabrook, near Portsmouth, N.H.; 

• Summer, near Columbia, S.C.; 

• South Texas Project Unit 1, near Bay City, Texas; 

• Vogtle Unit 1, near Augusta, Ga., and; 

• Waterford Unit 3, near New Orleans. 

The NRC expects to have enough information to decide the timing of these weld inspections 

by the end of this week. All of these plants have previously committed to inspect or mitigate 

these welds during their spring refueling maintenance over the next six weeks. The remaining 

61 PWR plants have either completed appropriate actions regarding their welds, or do not have 

welds susceptible to these flaws. 

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs Telephone: 301/415-8200 

Washington, D.C. 20555-0001 

E-mail: opa@nrc.gov 

Site: http://www.nrc.gov

No. 08-053 March 11, 2008
 Nuclear power plant components and piping are made of both carbon steel and stainless 

steel. These different metals are typically not welded to each other, so the plants used 

materials known as Alloy 82 and 182 for such welds, including on their pressurizer nozzles 

(see images below). These alloys have been susceptible in the past to cracking due to their 

chemical makeup, residual stresses from the welding process and PWR operating conditions. 

 

 The first incidence of these flaws was found in a U.S. reactor in 1993. Since 2000, 

nuclear power plants have documented additional flaws. As additional information has become 

available and inspection methods have improved, the NRC and the nuclear industry have 

progressively increased attention to detecting, evaluating and correcting the flaws. The NRC is 

reviewing enhanced inspection requirements from the American Society of Mechanical 

Engineers, and will add the requirements into the agency’s regulations as appropriate. More 

information regarding the issue is available on the NRC web site at: 

http://www.nrc.gov/reactors/operating/ops-experience/pressure-boundary-integrity/weldissues/. 
(Note to Editors: Members of the press interested in attending the meeting should contact the 

Office of Public Affairs by the close of business March 12 to arrange for audio or video 

recording.) 

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