U.S. NRC UPDATE ON BURIED A

UNDERGROUND PIPING AND TA

Brian Allik

September 2016
• Status of Buried Piping Action Plan• Issuance of Summary of Results from NR

Temporary Instruction (TI) 2515/182 (ADAAccession Number: ML16174A032)

• Update on Review of Operating Experienc• Issuance of License Renewal Interim Staf

Guidance, LR-ISG-2015-01, “Changes to and Underground Piping and Tank Recommendations” (ADAMS Accession Number: ML15308A018)

Outline
• Buried Piping Action Plan - The NRC reviewed codes, stan

regulations and industry practices related to degradation opiping and identified a number of ongoing activities. This atracked those activities. 

• Regulatory Outcome of Buried Piping Action Plan (from 20

– Staff concluded that current regulations ensure 

a. leakage from buried piping has been of low safety 

significance with respect to structural integrity

b. the amount of radioactive material that has been re

has been a small fraction of regulatory limits

– Rates of significant leakage events have exhibited a de

trend consistent with improved maintenance and inspepractices over the span of the action plan

Status of Buried PipAction Plan
• In November 2015 the NRC had completed all ac

items and closed the action plan 

– The staff will continue certain activities such as particip

codes and standards activities

– The staff will periodically meet with industry (e.g., ASM

EPRI)

– The staff will be routinely reviewing operating experien– These activities will no longer be tracked by the action 

Status of Buried PipAction Plan (cont.)
• NRC TI 2515/182, “Review of the Implementation 

Industry Initiative to Control Degradation of UndePiping and Tanks” 

– Phase I: Determine if licensees were implementing the 

initiative (i.e., NEI 09-14) on buried and underground ptanks 

– Phase II: Assess whether the industry initiative provide

reasonable assurance of the structural and leakage inteburied and underground piping and tanks

Issuance of Summary oResults from NRC TI 25
• Summary of Results from NRC TI 2515/182 (ADA

Accession Number: ML16174A032) was issued oJune 23, 2016

– Results of Phase I indicate that all licensees 

implemented the initiative and met established dates

– Results of Phase II indicate that all sites 

• perform effective risk ranking• have programs and have or are developing 

health reports

• are performing inspections of high risk buri

assets

Issuance of Summary of Refrom NRC TI 2515/182 (cont
– Results of Phase II indicate that many sites ar

making improvements to cathodic protection s

– The staff has concluded that these changes h

enabled utilities 

• to identify assets at risk for significant dete

and implement inspection, maintenance, reand replacement strategies 

• to provide reasonable assurance of the lon

reliability of buried and underground piping tanks

Issuance of Summary of Refrom NRC TI 2515/182 (cont
• NRC is continuing to review OE on an annual ba• Reports are internal to the NRC (not publically a• Latest review spanned from May 2015 – April 20• Majority of the leaks occurred in potable water s• Based on the staff’s review of the new event rep

there is no discernible trend of consequential pipleakage issues

Update on Review of O
• LR-ISG-2015-01, “Changes to Buried and Underground Piping a

Recommendations,” superseded LR-ISG-2011-03, ““Changes to Aging Lessons Learned (GALL) Report, Revision 2, Aging ManagProgram (AMP) XI.M41, ‘Buried and Underground Piping and Taprovide revisions to AMP XI.M41, “Buried and Underground PipinTanks” (ADAMS Accession Number: ML15308A018)

• Key Revisions Included:

– Significantly reduced the number of inspections when cathod

(CP) system is not meeting performance goals

• Category E (CP system does not meet Category C, coati

meet “preventative actions”, acceptable plant-specific opexperience, non-corrosive soil) – Reduced maximum insfrom 29 to 9 for steel, copper, and aluminum

• Category F (Does not meet Category E) - Reduced max

inspections from 60 to 18 for steel, copper, and aluminum

Overview of LR-ISG-20
• Key Revisions Included (cont.):

– Alternative Cathodic Protection Acceptance Criteria

• -750 mV relative to a copper/copper sulfate reference ele

(CSE) for soil resistivity of 10,000 – 100,000 

Ω-cm

• -650 mV relative to CSE for soil resistivity >100,000 

Ω-cm

• Verify less than 1 mpy loss of material, electrical resistan

rate probes 

Overview of LR-ISG-2015-01