EPRI’s Buried 

Pipe Initiative

Industry/NRC Meeting on PipeOctober 22, 2009Bo ClarkEPRI, BOP Corrosion Program M
EPRI’s Buried Pipe Initiative

• 2007 – Nuclear Power Council expresses concer• March 2008 - 1016276, “An Assessment of Indus

Needs for Control of Degradation in Buried Pipe”

– Gap Analysis Identified needs for:

• 1

) Guidelines to Co

n

t

r

ol Deg

radation 

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2

) Gu de es to Co t o eg adat o

• 2) Risk Ranking Method for buried pipe• 3) Technical Resources document for buried • 4) Dedicated test facility• 5) Experience sharing• 6) Assess and Develop Inspection Tools• 7) Training 
EPRI’s Buried Pipe Strategic Activities

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Program Guidance

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Program Guidance

• 1016456, Recommendations for an Effective Prog

Control the Degradation of Buried Pipe 

– Rev. 1 in progress– Discussed in depth later

• Training for Buried Pipe Program Owners

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a g o u ed pe og a O e s

– June 2-4, 2009– Sept 9-11, 2009– November 10-12, 2009, Dallas 
Program Guidance (continued)

• NRC/NEI/INPO Interface

– INPO uses “Recommendations” document as 

for BP program evaluation

• Program feedback

–

Met wi

th NEI

/NR

C

on Aug 1

9-20, 2009

on B

ur

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6

et t / C o ug 9 0, 009 o u 

and ASME Code Case N-755 on HDPE
Risk Ranking Software

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Risk Ranking Software

• Risk Ranking - used to prioritize the selection of inspe

locations. 

– Correlates the likelihood of failure against the conse

of failure. 

Risk

= Likelihood X Consequen

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• BPWORKS V1.0a

– Open Database being developed in V2.0– Other commercially available tools also exist– Training - BPWORKS Software

Risk Likelihood

X Consequen
Buried Pipe Integrity Group (BPIG)

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Buried Pipe Integrity Group (BPIG)

• Buried Pipe Integrity Group (BPIG) formed in 200

– In 2010, all US Utilities will be members

– Meets two times/year

• Provides:

– Forum for 

plant owners to discuss buried 

pipe 

© 2009 Electric Power Research Institute, Inc. All rights reserved. 10

p pp

and exchange experiences (OE Sharing)

– Forum to obtain a consensus on industry issue

– Technical support on buried pipe issues, as we

support for related products

– Related training– Interface with Vendor Support

• Sponsor related R&D
Condition Assessment of Pipe O.D. Coat

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Condition Assessment of Pipe O.D. Coat

• Indirect Inspection Methods Used in Pipeli

Industry

• Pipe-to-Soil potential• Direct Current Voltage Gradient (DCVG)• Pearson survey

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Pearson survey

• AC Current Attenuation• Close Interval Potential Survey• Area Potential Earth Current (APEC)

• Application challenges 

– Congested Plant Piping
Condition Assessment of Pipe O.D. Coat

• Briefly Covered in 

Training for Buried Pipe Program Owners

•Discussed in

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Discussed in

depth in Cathodic Protection / Indirect Inspection Training
Cathodic Protection

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Cathodic Protection (CP)

• O.D. Coating - First Line of Defense against exter

corrosion

– Cathodic Protection - Backup Defense for area

damaged coating

• CP Training

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CP Training

– NMAC’s CP Workshop– BP Program Owners’ Training– CP Field Training Covered in Cathodic Protect

Indirect Inspection Course
Condition Assessment of Pipe

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Condition Assessment of Buried Pipe

• Ongoing Research

– Internal Pipe NDE Inspection Vehicles– Guided Wave NDE– Buried Pipe Mockups

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• Proposed/Planned Research

– 10” & smaller internal vehicles– Buried pipe location & mapping
In-Line Instrumented Vehicles

• There are commercial offerings 

that offer in-line inspections of pipe wall thickness (pigs)

• Limitations:

– In-ability to go through elbows, 

tees, valves, elevation chan

ges

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– Require dedicated launch and 

retrieval stations

– Require 1/8” liftoff for accurate 

detection & sizing of pits

• Since 2004 EPRI has been 

developing vehicles and sensors suited for power plant piping (1” liftoff to accommodate pipe crud)
Vehicle for Large Diameter Pipe Inspecti

• ‘Proof of Concept’ of EPRI vehicle for very large 

diameter buried pipe (36” < D < 12’) completed 

• Detect

− Internal and external pits− Circumferential weld 

Exciter 

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degradation

− Longitudinal weld 

degradation 

• Install through 24” diameter 

man way

• Can disassemble to pass 

through elbows

Detector Array
Vehicle for Intermediate Diameter Pipe

• “Proof of Concept” -facilitate 

pipe inspection (12” to 30” diameter)

• Pulls itself along a guide wire• 1” of radial clearance to allow for 

d t b l ti t

Instrument Modules

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mu

d, t

u

bercles, coatings, e

t

c

• Can traverse

– Change of elevations– Branches, tees– Multiple elbows (at least 6)

• Field testing in 2010

Spring Loaded Wheels

Sensors
Project Timeline

Deliverable Title Scheduled Condition Assessment of buried Piping of Intermediate diameter

12/31/2009

Condition Assessment of Buried Piping of Intermediate Diameter-Field Trial

12/31/2010

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Condition Assessment of Buried Piping that Cannot be Drained-Engineering Design

12/31/2011

Condition Assessment of Buried Piping that cannot be drained-Manufacturing and Lab evaluation

12/30/2012

Condition Assessment of Buried Piping that cannot be drained-Field Trial

12/30/2013
Guided Wave Ultrasonics

• Guided Wave ultrasonics is an existing technolog

being extended to inspect buried pipe

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Guided Wave Ultrasonics

– 100% volumetric coverage over 

length of exam

– Screens for change in cross 

section area; can be focused

• Multiple sensors are wrapped around pipe and sen

both directions. Provides

© 2009 Electric Power Research Institute, Inc. All rights reserved. 23

section area; can be focused

on a specific area

– Ability to inspect under 

coatings, in inaccessible areas, and without complete excavation

– Length of exam limited by 

coatings, ground compaction, elbows Piezoelectric Sen
Guided Wave Variables

Guided wave technology for buried pipe examination is:• Relatively new and is emerging

– Capabilities and limitations are not well known/documen

Flaw characterization is currently limited

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Several complex factors affect successful application

– Piping geometry– Coating type and thickness– Flaw shape and depth– Surface conditions– Multiple flaws– Inspection distance
Guided Wave Pipe Mock-ups

EPRI is building two piping mock-ups• 24” diameter 0.375” thick carbon steel

– Most common based on industry survey

• Un-coated Mock-up status

– Welded together

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– Flaw implant scheduled to start in October

• Coated mock-up status

– Piping has been coated and ready to ship– Construction scheduled for 4th quarter

– Flaw implant to begin after studies on un-coated mock-u

complete
Un-coated Mock-up

Purpose • Study guided wave 

– Interaction on multiple flaw shapes independe

coating variables

– Response through elbow 

• Process and technology development

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Process and technology development

• Develop training and test specimen• Validation of computer modeling• Identify appropriate flaw characteristics for buried 

up 
Un-coated Mock-up

• Guide wave collar

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Coated Mock-up

Purpose• Identify Gaps• Develop advanced GW techniques

– Improve detection (including around elbows)

Improve flaw characterization

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– Improve flaw characterization– Focusing– Signal processing

• Benchmark technologies• Study effects of coating on GW (attenuation)

• Develop/validate modeling• Not intended as a qualification mock-up
Coated Mock-up (continued)

Variables within mockup• Multiple coatings – coal tar enamel and coal tar e• Multiple flaw shapes and sizes• Multiple data acquisition locations

© 2009 Electric Power Research Institute, Inc. All rights reserved. 29

Vendor Capability Demonstrations• Invite NDE Services vendors to perform blind 

demonstrations; publish the results
EPRI Buried Pipe Mockup Layout

5

6

7

8

9

13B

1

2

3

4

12A

13A

20’

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Coal Tar EnamelCoal Tar Epoxy

Access PointBackfill

QUANTITIES10 – 20’ 24” OD .375” Wall CS Pipe Sections

5 – CT Enamel A106B5 – CT Epoxy A106B

3 – 10’ 24” OD .375” Wall CS Pipe Sections A10

3 - No coating

4 – 90 elbows1 – 45 bend1 - Tee
Schedule

Uncoated Mock-up• Fabrication complete

– Flaws to be inserted 4th quarter of 2009

Coated Mock-up

• Coating complete

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Coating complete

• Fabrication to be completed during 4th quarter of 

• Flaws to be inserted 1st quarter of 2010

• Backfill to occur after initial R&D and evaluation o

inserted flaws
Future Vision

• Potential use for demonstration or qualification of 

capabilities

– Use of NDE data to produce Virtual Pipe Spec

• Two possibilities

– Embed recorded flaw data into data files 

from clean pipes

© 2009 Electric Power Research Institute, Inc. All rights reserved. 32

from clean pipes

– Use models to develop NDE responses t

flaws, embed into clean pipe data

– Enables preparation of unlimited varieties of 

specimens for blind demonstrations or qualific

• Varied flaw types, locations, configurations 

for example), test conditions (soils, coatingstemperature, ...)
Repair / Replacement

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Repair / Replacement

Cured-in-Place Pipe (CIPP)• ASME Code Case N589-1 

provides rules for cured-inplace pipe (CIPP) to be used to repair Class 3 piping

© 2009 Electric Power Research Institute, Inc. All rights reserved. 34

– However, R.G. 1.193 did 

not approve its use

• Although the CIPP products 

have many limitations, there are many applications where they are useful Insertion of an Inv
Repair / Replacement

High Density Polyethylene (HDPE)• Considered to be an attractive option for replacem

degraded pipe

• Extensive effort underway to support ASME to rev

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obtain approval for Code Case N-755

• Details of R&D activities on HDPE were discussed 

during public meeting on August 20, 2009
Buried Pipe Strategic Activities

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Together...Shaping the Future of Elect

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