GCN / Subgerencia de Ingeniería
INTRODUCTION
2
- 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
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.
7
EMBEDDED PIPING
GCN / Subgerencia de Ingeniería
8
Buried Piping
CARBON STEEL
PIPING
STAINLES STEEL
PIPING
CuNi PIPING
REF. M-3150
GCN / Subgerencia de Ingeniería
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.
9
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.
10
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.
11
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."
12
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:
13
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.
14
LRA – AMR/AMP
Top Related