Laguna Verde Buried Piping Operating

Experience

CFE LVNPP – Juan Mercado

October, 2013

GCN / Subgerencia de Ingeniería

INTRODUCTION

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- In-service failure may impact

safety and plant operations that

represent high cost.

- Solution involves actions to Establish

reasonable assurance of structural

and leakage integrity of underground

piping & tanks.

GCN / Subgerencia de Ingeniería

SOLUTIONS FOR

THE BURIED PIPE ISSUES

• Mitigate and Arrest Degradation

Develop Cathodic Protection and pipe

coatings technologies that serve to stop

further corrosion

• Program Support & Reference Materials

Develop plans to effectively identify,

monitor and manage buried pipe

degradation

GCN / Subgerencia de Ingeniería

• Diagnostic techniques

Develop NDE Techniques that are

effective at for finding and analyzing

degradation in pipe

• Repair/Replace Tools

Develop guidance and techniques for

repairing or replacing buried pipe when

required Coatings

SOLUTIONS FOR

THE BURIED PIPE ISSUES

GCN / Subgerencia de Ingeniería

DESIGN

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Laguna Verde NPP

GCN / Subgerencia de Ingeniería

CENTRAL NUCLEOELÉCTRICA LAGUNA VERDE

Laguna Verde, Veracruz;

70 km. NNW FROM VERACRUZ City.

Number for Units: 2

Reactor:

BWR/5 General Electric

Turbo-Generator:

Before EPU: Mitsubishi Heavy Industries

After EPU: ALSTOM

Capacity per Unit:

Before: 682 MWe

After:810 MWe

Commercial Operation (start):

- Unit 1: July 29, 1990

- Unit 2: Aplril 10, 1995

Laguna Verde NPP

GCN / Subgerencia de Ingeniería

• ALL BUILDINGS:

- FLOOR DRAIN SYSTEMS: SS PIPE TYPE 304, SCHEDULE 10, ASTM A312.

- FOR CHEMICAL WASTE RADIOACTIVE (CWR): SS PIPE TYPE 316L, SCHEDULE 40, ASTM A-312.

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EMBEDDED PIPING

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Buried Piping

CARBON STEEL

PIPING

STAINLES STEEL

PIPING

CuNi PIPING

REF. M-3150

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PIPE COATING

• Pipe coating for buried Carbon Steel pipe is polyethylene film with a bonding adhesive.

• Pipe coating for buried Stainless Steel and CuNi pipe is polyethylene copolymer-film backing and compouned synthetic elastaners resins and filler adhesive layer.

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GCN / Subgerencia de Ingeniería

LRA – AMR/AMP

XI.M.41Buried and Underground Piping and Tanks

(developing)

This program manages the effects of aging for

buried and underground piping. The program

addresses aging effects such as loss of material

due to corrosion, cracking, and changes in

material properties.

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GCN / Subgerencia de Ingeniería

Systems, environments and materials covered by

this program:

• EDG system: Buried Carbon Steel/Cooper nickel

pipe.

• CSS system: Buried Stainless Steel pipe.

• HPCS system: Buried Stainless Steel pipe.

• NSW system: Buried CopperNickel pipe.

• M23H system: Buried Carbon Steel pipe.

There are not underground piping and tanks in

scope of LRA.

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LRA – AMR/AMP

GCN / Subgerencia de Ingeniería

• The Fire Protection System was installed in accordance with National Fire Protection Association (NFPA) Standard 24 and is subject to a flow test as described in section 7.3 of NFPA 25 at a frequency of once a year. Therefore, direct inspections are not required per XI.M41, "Buried and Underground Piping and Tanks."

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LRA – AMR/AMP

GCN / Subgerencia de Ingeniería

• All buried piping, regardless of their construction material, are inspected by visual means whenever they become accessible for any reason.

• Direct inspections of buried piping will be each 10-year period for both units, the systems are as follows:

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LRA – AMR/AMP

GCN / Subgerencia de Ingeniería

- EDG system: Buried Carbon Steel pipe/Copper Nickel

pipe.

- CSS system: Buried Stainless Steel pipe.

- HPCS system: Buried Stainless Steel pipe.

- NSW system: Buried Copper Nickel pipe.

• Inspection locations are selected based on risk,

considering the coating condition, cathodic protection

effectiveness, backfill characteristics, soil resistivity, pipe

contents, and pipe function. Pipes with a compacted

backfill will be selected instead of pipes under concrete

floor.

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LRA – AMR/AMP

GCN / Subgerencia de Ingeniería

THANK YOU!!

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