Laguna Verde Buried Piping Operating Experience. CFE LVNPP Juan Mercado

Transcription

1 Laguna Verde Buried Piping Operating Experience CFE LVNPP Juan Mercado October, 2013

2 INTRODUCTION - 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. 2

3 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

4 Diagnostic techniques Develop NDE Techniques that are effective at for finding and analyzing degradation in pipe Repair/Replace Tools SOLUTIONS FOR THE BURIED PIPE ISSUES Develop guidance and techniques for repairing or replacing buried pipe when required Coatings

5 Laguna Verde NPP DESIGN 5

6 CENTRAL NUCLEOELÉCTRICA LAGUNA VERDE Laguna Verde NPP 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, Unit 2: Aplril 10, 1995

7 EMBEDDED PIPING ALL BUILDINGS: - FLOOR DRAIN SYSTEMS: SS PIPE TYPE 304, SCHEDULE 10, ASTM A FOR CHEMICAL WASTE RADIOACTIVE (CWR): SS PIPE TYPE 316L, SCHEDULE 40, ASTM A

8 Buried Piping CARBON STEEL PIPING STAINLES STEEL PIPING CuNi PIPING REF. M

9 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

10 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

11 LRA AMR/AMP 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

12 LRA AMR/AMP 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

13 LRA AMR/AMP 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

14 LRA AMR/AMP - 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

15 THANK YOU!! 15