1776 I Street, NW l Suite 400 l Washington, DC l 20006-3708 l P: 202.739.8080 l F: 202.533.0164 l axm@nei.org l www.nei.org 

Alexander Marion 

VICE PRESIDENT

NUCLEAR OPERATIONS

NUCLEAR GENERATION DIVISION

May 17, 2011 

Ms. Michele G. Evans 

Director, Division of Component Integrity 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

Subject: Response to Request for Underground Piping Information 

Project Number: 689 

Dear Ms. Evans: 

On August 18, 2010, you sent a letter to NEI requesting information related to the design and leakage 

history of underground piping at nuclear power plants. The NEI Buried Piping Integrity Task Force 

worked with your Staff to clearly define the information requested and to develop a spreadsheet to 

capture the desired data. The purpose of this letter is to submit the spreadsheet that summarizes the 

data received. 

The following general points pertain to the information in the attached spreadsheet. See attachment 1 

for an explanation of how the data was entered into the spreadsheet, a list of abbreviations, and 

observations. 

• The underground piping data was obtained by survey using the following process. A spreadsheet 

similar to the one attached to this letter was distributed to every utility. The spreadsheet was 

completed for each unit according to instructions similar to those included in the attachment to 

this letter. The completed spreadsheets were assembled by NEI into an Excel workbook and the 

summary information obtained by processing the data received using spreadsheet functions. The 

resulting workbook contains four worksheets: BWR Totals, PWR Totals, Overall Totals, and 

Charts. 

• Responses were received from all 104 units. Utilities and plant names are not identified in the 

attached spreadsheet and will not be provided per our agreement with your Staff. 

• The NEI Buried Piping Integrity Task Force reviewed all the data provided in an attempt to 

reduce inconsistency and inaccuracy, however the data was not verified and would best be used 

to obtain general trends. Questions on the input received were addressed prior to submitting the 

information to you. 
Ms. Michele G. Evans 

May 17, 2011 

Page 2 

• The information was obtained for “important” systems with underground piping segments. 

o “Important” systems are defined as those that are safety related, contain or are 

contaminated with licensed material, or contain environmentally hazardous material. 

o Underground Piping is defined in NEI 09-14, revision 1 as: “All piping that is below grade, 

not accessible, and outside of buildings.”

Note that Utility characterization of a system as “important” or not “important” was not 

challenged by the task force unless it was an apparent error. 

• The “importance” categorization of some generic systems differed between plants (fire protection 

is the best example). As a result, information on the number of plants that bury those systems 

and the leakage trend for the systems can be misinterpreted if not understood in this context. 

For example, the information in the spreadsheet indicates that 9 plants have portions of their fire 

protection system underground. In fact, portions of the fire protection system piping are located 

underground at all plants, but only 9 plants categorized the fire protection system as “important”. 

• Many plants listed plant specific important systems in their response to the information request. 

The Buried Piping Integrity Task Force changed these types of responses in the following ways so 

that all the plant specific input was captured. 

o To the extent possible, information on plant specific systems was applied to one of the 

generic system names listed in the spreadsheet that most closely matched the function of 

the plant specific system. 

o Several new generic system names were added to the last 5 lines of the spreadsheet and 

the rest of the plant specific information was moved to these lines. 

• Our evaluation of the data did not reveal any surprising information. For example, the systems 

that are most frequently buried, the materials of fabrication, and the number of leaks were 

generally what was expected. 

If you have any questions on this matter, please contact me or Jim Riley at 202-739-8137; jhr@nei.org. 

Sincerely, 

Alexander Marion 

Attachments 

c: Mr. John W. Lubinski, NRR/DCI, NRC 

Mr. Robert O. Hardies, NRR/DCI, NRC 

Buried Piping Integrity Task Force 

 Buried Piping Integrity Working Group