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{{#Wiki_filter:ATTACHMENT 9.1 ENGINEERING REPORT COVER SHEET & INSTRUCTIONS Engineering Report No. IP-RPT | {{#Wiki_filter:NYS000178 Submitted: December 16, 2011 ATTACHMENT 9.1 ENGINEERING REPORT COVER SHEET & INSTRUCTIONS Engineering Report No. IP-RPT Rev 0 00011 Page of | ||
0 Yes GJ No Prepared by: | -- Entergy ENTERGY NUCLEAR Engineering Report Cover Sheet Engineering Report | ||
.::: | |||
-.,-,----- | ==Title:== | ||
Responsible Engineer (Print Name/Sign) | Corrosion/Cathodic Protection Field Survey and Assessment of Underground Structures at Indian Point Energy Center Unit Nos. 2 and 3 during October 2008 Engineering Report Type: | ||
New GJ Revision 0 Cancelled 0 Superseded 0 Applicable Site(s) | |||
s..:.:n:.::. | IPI GJ IP2 GJ IP3 GJ JAF 0 PNPS 0 VY 0 WPO 0 ANO! 0 AN02 0 0 0 0 0 ECH GGNS RBS WF3 PLP 0 DRN No. ON/A; 0 __ | ||
Report Origin: 0 Entergy GJ Vendor Vendor Document No.: PCA Job No. 28457 Quality-Related: 0 Yes GJ No Prepared by: _ _ _ _ _ __::P::..,C::.:A~E:.:.:n:2g:.:.:in:.:.ee::..::r..:.:in;:;;gu.,.: :In::. : c:.:. . - . , - , - - - - - Date: 12/2/08 Responsible Engineer (Print Name/Sign) | |||
Reviewed by: ** For ASME Section XI Code Program plans per ENN-DC-120. | Not Design Veri tied! _ _ _ __:.D=:,e:.::s;:;;ig~:.:n~V:....:e::.r::..::if::..::lc-=at:.:.:io:..:n::._l:.:..s..:.:n:.::.o::._tR:.: .:. :eq:I.;u:.:.:ir:.: e; ; d_ _ __ Date: Required Design Verifier (if required) (Print Name/Sign) | ||
if require | Reviewed by: | ||
Not Date: Required | |||
None Comment Section/ Page No. Review Comment Response/Resolution Preparer's | ** For ASME Section XI Code Program plans per ENN-DC-120. if require EN-DC-147 REV 3 IPEC00220850 IPEC00220850 | ||
IPEC I System l Ph. 914-271-Date: I | "'U m | ||
() | |||
0 0 | |||
I'V I'V 0 | |||
CX> ATTACHMENT 9.5 TECHNICAL REVIEW COMMENTS AND RESOLUTION FORM CJl | |||
....... SHEET1 OF 1 A~~ Entergy Engineering Report Technical Review Comments and Resolutions Form Engineering Rev. | |||
==Title:== | |||
Corrosion/Cathodic Protection Field Survey and Assessment of Report Number IP-RPT 00011 0 Underground Structures at Indian Point Energy Center Unit Nos. 2 and 3 during October 2008 Quality Related: DYes [8J No Special Notes or Instructions: None Comment Section/ Page No. Review Comment Response/Resolution Preparer's ! | |||
Number Accept Initials No N/A Comments I 2126/09 I N/A Verified/Reviewed By: | |||
Site/Department: | |||
Christopher A Ingrassia IPEC I System Engineering l Ph. 914-271-7047 Date Resolved By: | |||
Date: | |||
I | |||
"'0 m | |||
() | |||
0 0 | |||
~ EN-DC-147 REV 3 | |||
~ | |||
0 00 (J'1 | |||
Prepared fcr: | |||
Entergy Nuclear Operations, Inc. | |||
Indian Point Energy Center 450 Broadway Buchanan, NY 10511 Corrosion I Catl10dic Prolection F'leld Survey and - d of Underground StiUctLres at Indian Point Energy Center Unit Nos. 2 and 3 Prepa"ed by: | |||
PCA Engineering, Inc. | |||
430 Montdar Avenue P.O. Box196 Pompton Lakes, NJ 07442 PCA Job No. 28457 November 10, 2008 Revised December 2, 2008 IPEC00220852 IPEC00220852 | |||
I. INTRODUCTION During the month of October 2008, PCA Engineering, Inc. personnel performed a corrosion/cathodic protection field survey and assessment of the underground structures associated with the Entergy Nuclear Operations Indian Point Unit Nos. 2 and 3 Facility located in Buchanan, New York. | |||
This included a review of site drawings and a site survey. The field survey procedures essentially consisted of structure-to-soil potential measurements, electrical isolation testing, temporary impressed current testing and soil resistivity measurements. | |||
II. SITE DESCRIPTION The operating systems at the Indian Point Facility consist of Unit Nos. 2 and 3, estimated to be in operation since approximately 1968. The underground piping and structures under consideration as part of this investigation include the following: | II. SITE DESCRIPTION The operating systems at the Indian Point Facility consist of Unit Nos. 2 and 3, estimated to be in operation since approximately 1968. The underground piping and structures under consideration as part of this investigation include the following: | ||
* Intake Structure, including sheet piling | * Intake Structure, including sheet piling | ||
* Circulating Water Piping | * Circulating Water Piping | ||
* Service Water Piping | * Service Water Piping Page 1 of 18 PCA ENGINEERING, INC. | ||
{Cont'd) | IPEC00220853 IPEC00220853 | ||
II. SITE DESCRIPTION {Cont'd) | |||
* Condensate Piping | * Condensate Piping | ||
* City Water Piping | * City Water Piping | ||
* Underground Diesel Generator Tanks The majority of the underground piping is reported to be welded carbon steel. The construction specifications called for external coal tar coating or tape wrapped pipe. It is unknown if the piping was inspected for quality and coating holidays at the time of installation. | * Underground Diesel Generator Tanks The majority of the underground piping is reported to be welded carbon steel. The construction specifications called for external coal tar coating or tape wrapped pipe. | ||
The service water and city water service piping are also reported to be cement lined. The intake structure consists of a sheet piling wall located on the north and south sides of Unit No. 2 and Unit No. 3. An additional segment of sheet pile wall also extends south of Unit No. 3. The circulating water piping consists of six (6) 84-inch underground pipes for each of the two units. The service water piping primarily consists of two (2) 24-inch underground pipes with some smaller runs of piping for each of the two units. | It is unknown if the piping was inspected for quality and coating holidays at the time of installation. The service water and city water service piping are also reported to be cement lined. | ||
The original cathodic protection design was not based upon providing electrical isolation of the protected underground piping from the unprotected copper grounding grid or other metallic structures (i.e. building steel, aboveground piping, reinforcing steel) . The underground portion of the Unit No. 2 condensate piping is located between the on-grade Condensate Storage Tank and Auxiliary Feed Pump Building and consists of a 12, 10 and 8-inch carbon steel coated pipe. The corresponding lines at Unit No. 3 are aboveground (heat traced, insulated and jacketed). | The intake structure consists of a sheet piling wall located on the north and south sides of Unit No. 2 and Unit No. 3. An additional segment of sheet pile wall also extends south of Unit No. 3. | ||
The circulating water piping consists of six (6) 84-inch underground pipes for each of the two units. The service water piping primarily consists of two (2) 24-inch underground pipes with some smaller runs of piping for each of the two units. | |||
The tanks at the Unit No. 2 Diesel Generator Building consist of three (3) 7,700-gallon capacity underground storage tanks. These tanks are mounded and reported to be backfilled with sand. Two (2) underground diesel tanks associated with Unit No. 3 were also investigated. | Page 2 of 18 PCA ENGINEERING, INC. | ||
This consisted of a TSC diesel tank and an APR diesel tank. The TSC tank was found to be of sti-P3 (Steel Tank Institute | IPEC00220854 IPEC00220854 | ||
Temporary impressed current testing was performed using a portable 80-volt, 8-amp rectifier. | II. SITE DESCRIPTION (Cont'd) | ||
Two (2) existing rectifiers at Unit No. 2 were also employed for the testing. Soil resistivity readings were obtained using the Wenner 4-Pin Method in conjunction with a Nilsson Model 400 Soil Resistance Meter. Resistivity measurements were obtained at representative depths of 5 feet, 10 feet and 15 feet. IV. CORROSION/CATHODIC PROTECTION | An impressed current cathodic protection system was installed during power plant construction for the intake structures and the circulating/service water piping. The majority of these systems have been removed or are out of service, with the exception of that for the intake structure sheet piling associated with Unit No. 2. An impressed current cathodic protection system is also in place for the Unit No. 1 main dock, but is not a part of this investigation. The original cathodic protection design was not based upon providing electrical isolation of the protected underground piping from the unprotected copper grounding grid or other metallic structures (i.e. building steel, aboveground piping, reinforcing steel) . | ||
-GENERAL | The underground portion of the Unit No. 2 condensate piping is located between the on-grade Condensate Storage Tank and Auxiliary Feed Pump Building and consists of a 12, 10 and 8-inch carbon steel coated pipe. The corresponding lines at Unit No. 3 are aboveground (heat traced, insulated and jacketed). | ||
: 1. Corrosion of Buried Structures Corrosion is an electrochemical process by which steel and other metals attempt to return to their natural ore condition. | Page 3 of 18 PCA ENGINEERING, INC. | ||
In this process, the metal lS corroded by discharges of electrical metallic ions to earth. There are many different causes of corrosion, among which the most common are: Page 5 of 18 PCA ENGINEERING, INC. IPEC00220857 IV. CORROSION/CATHODIC PROTECTION-GENERAL (Cont'd) | IPEC00220855 IPEC00220855 | ||
Corrosiveness of soil is generally an inverse function of the resistivity. | |||
Lower resistivity soils are generally considered to be more corrosive than soils of higher resistivity. | II. SITE DESCRIPTION (Cont'd) | ||
The general classifications of soil resistivity relating to the degree of corrosivity are as follows: a) 0 to 2,000 ohm/em-extremely corrosive b) 2,000 to 10,000 ohm/em-moderately corrosive c) 10,000 to 30,000 ohm/em-mildly corrosive d) 30,000 ohm/em and over-progressively less corrosive These classifications are general. Under certain conditions, severe corrosion can occur in the higher resistivity soil. Large variations in resistivity indicate the existence of variations in soil composition, and such variations can be conducive to the creation of galvanic corrosion activity on an underground structure. | The applicable portion of the City Water Piping consists of a 16-inch steel cement lined pipe located between the on-grade water storage tank at Broadway and the Air Monitor House. The pipe is then installed within a utility tunnel. The city water piping crosses the Algonquin Gas Pipeline. | ||
Page 7 of 18 PCA ENGINEERING, INC. IPEC00220859 IV. CORROSION/CATHODIC PROTECTION-GENERAL (Cont'd) | The tanks at the Unit No. 2 Diesel Generator Building consist of three (3) 7,700-gallon capacity underground storage tanks. These tanks are mounded and reported to be backfilled with sand. Two (2) underground diesel tanks associated with Unit No. 3 were also investigated. This consisted of a TSC diesel tank and an APR diesel tank. The TSC tank was found to be of sti-P3 (Steel Tank Institute - | ||
: 2. Cathodic Protection In order to stop corrosion, the natural flow of current from a metallic structure to earth has to be stopped. This can be accomplished by the use of sacrificial anodes that supply current to earth, which is picked up by the structure, thus reversing the flow of current and stopping the corrosion process; this lS called cathodic protection. | corrosion protected) construction and the APR tank was observed to be located in a concrete vault. | ||
Sacrificial anodes, such as magnesium, make use of the voltage difference between the structure metal and the anode material. | Page 4 of 18 PCA ENGINEERING, INC. | ||
The anode is always more negative than the structure; therefore, the flow of current through the wire connection is from structure to anode and the flow of current through the electrolyte (earth) is from anode to structure. | IPEC00220856 IPEC00220856 | ||
The impressed current type of cathodic protection makes use of a DC output rectifier. | |||
The current output from the rectifier is discharged to earth through anodes. The current, in turn, is picked up by the structure in contact with the earth (providing cathodic protection in the process) and returns through cable connections to the negative terminal of the rectifier. | III. TEST PROCEDURES Pipe-to-soil potential measurements were obtained using a Fluke Model 77 Digital Voltmeter and a portable copper/copper sulfate reference electrode. Temporary impressed current testing was performed using a portable 80-volt, 8-amp rectifier. Two (2) existing rectifiers at Unit No. 2 were also employed for the testing. | ||
Page 8 of 18 PCA ENGINEERING, INC. IPEC00220860 V. CRITERIA FOR CATHODIC PROTECTION The criteria for determining the adequacy of protection on a buried structure is defined in the NACE Recommended Practice SP0169-2008 entitled "Control of External Corrosion on Underground or Submerged Metallic Piping Systems". | Soil resistivity readings were obtained using the Wenner 4-Pin Method in conjunction with a Nilsson Model 400 Soil Resistance Meter. Resistivity measurements were obtained at representative depths of 5 feet, 10 feet and 15 feet. | ||
In essence, the requirements for steel structures are as follows: | IV. CORROSION/CATHODIC PROTECTION - GENERAL | ||
B. A negative polarized potential* | : 1. Corrosion of Buried Structures Corrosion is an electrochemical process by which steel and other metals attempt to return to their natural ore condition. In this process, the metal lS corroded by discharges of electrical metallic ions to earth. | ||
of at least 850 mV relative to a saturated copper/copper sulfate reference cell. *Polarized Potential: | There are many different causes of corrosion, among which the most common are: | ||
The potential across the structure/electrolyte interface that is the sum of the corrosion potential and the cathodic polarization. | Page 5 of 18 PCA ENGINEERING, INC. | ||
Page 9 of 18 PCA ENGINEERING; INC. IPEC00220861 V. CRITERIA FOR CATHODIC PROTECTION (Cont'd) C. A minimum polarization voltage shift of 100 mV as measured between the structure and a saturated copper/copper sulfate reference cell contacting the earth directly over the structure. | IPEC00220857 IPEC00220857 | ||
This polarization voltage shift shall be determined by interrupting the protective current and measuring the polarization decay. When the protective current is interrupted, an immediate voltage shift will occur. The voltage reading, after the immediate shift, shall be used as the base reading from which to measure polarization decay. VI. TEST RESULTS AND RECOMMENDATIONS The prior surveys of the Unit No. 2 sheet piling performed in 2006 and 2008 generally indicate satisfactory levels of cathodic protection were being provided to the structures (with some limitations of available test locations). | |||
The results of these surveys were furnished in a separate report. | IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd) a) Dissimilar metals that are electrically tied together b) Dissimilar soils c) Differential aeration d) Anaerobic bacteria e) Outside sources of D.C. current Power plants generally consist of a congested underground environment consisting of multiple service piping in the presence of an extensive grounding network. The existence of underground piping of various materials of construction (i.e. steel, ductile iron) in the presence of a bare copper grounding network is conducive to galvanic corrosion from dissimilar metals. The corrosion is detrimental to the ferrous piping materials as it is anodic in the presence of copper. Any breaks or holidays in the pipe coating are conducive to a high ratio of anode to cathode. This can lead to accelerated rates of corrosion in steel and ferrous materials, particularly if scil resistivity is low. | ||
As expected, the test data indicates all "as found" potential measurements for the piping are below the 850 millivolt criteria as an indication of satisfactory cathodic protection as described ln Section V of this report. This was to be expected as there is no dedicated cathodic protection on these structures. | Page 6 of 18 PCA ENGINEERING, INC. | ||
With an additional 100 amperes of impressed current applied during the survey, the Unit No. 2 circulating water piping showed potential shifts of less than 10 millivolts as compared to the as found potential. | IPEC00220858 IPEC00220858 | ||
This demonstrates a very limited distribution of protective current and the | |||
A review of the original cathodic protection plan drawings indicates the installation of distributed high silicon iron anodes for the intake structures and the sheet piling. These components were installed during plant construction. | IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd) | ||
There is little historical operational data to indicate the level of effectiveness of the system. With the exception of the Unit No. 2 intake structure sheet piling and a sewage pipeline operating cathodic protection system, all other original cathodic protection systems have been removed and/or abandoned. | Soil resistivity measurements indicate the relative ability of the earth to carry electrical currents. Corrosiveness of soil is generally an inverse function of the resistivity. Lower resistivity soils are generally considered to be more corrosive than soils of higher resistivity. | ||
The city water piping potentials are as shown on the enclosed Data Table III. The most significant finding of the field testing indicates a positive shift in the potentials of the city water piping where it crosses the Algonquin gas pipeline. | The general classifications of soil resistivity relating to the degree of corrosivity are as follows: | ||
This static stray current is | a) 0 to 2,000 ohm/em- extremely corrosive b) 2,000 to 10,000 ohm/em- moderately corrosive c) 10,000 to 30,000 ohm/em- mildly corrosive d) 30,000 ohm/em and over- progressively less corrosive These classifications are general. Under certain conditions, severe corrosion can occur in the higher resistivity soil. Large variations in resistivity indicate the existence of variations in soil composition, and such variations can be conducive to the creation of galvanic corrosion activity on an underground structure. | ||
Stray current can result in serious corrosion at the point of current discharge from the "foreign" pipe. Impressed current demand testing utilized two steel bollards as temporary anodes near the Broadway storage tank and provided 2 amperes of current. This provided only some localized protection to the piping near the storage tank and reduced the magnitude of the effect of the stray current. The Diesel Generator Tank Nos. 21, 22 and 23 were found to be unprotected as there is no cathodic protection system associated with these structures. | Page 7 of 18 PCA ENGINEERING, INC. | ||
The TSC diesel tank was found to be of sti-P 3 construction and partially protected. | IPEC00220859 IPEC00220859 | ||
Tanks of sti-P 3 construction include a high quality external coating, factory installed galvanic anodes and electrical isolation as a defense against corrosion. | |||
The APR tank could not be accessed as it was located within a vault identified as a confined space entry. | IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd) | ||
The installation of a cathodic protection system after plant construction can become difficult and generally expensive. | : 2. Cathodic Protection In order to stop corrosion, the natural flow of current from a metallic structure to earth has to be stopped. This can be accomplished by the use of sacrificial anodes that supply current to earth, which is picked up by the structure, thus reversing the flow of current and stopping the corrosion process; this lS called cathodic protection. | ||
This problem is exaggerated in the presence of subsurface rock as reported for this site. Impressed current system options include distributed anodes, linear anodes and anode deepwell systems. Connection of the copper grounding system to an impressed current system increases cathodic protection requirements by several order of magnitude. | Sacrificial anodes, such as magnesium, make use of the voltage difference between the structure metal and the anode material. The anode is always more negative than the structure; therefore, the flow of current through the wire connection is from structure to anode and the flow of current through the electrolyte (earth) is from anode to structure. | ||
Bare copper structures are difficult to polarize as compared to steel | The impressed current type of cathodic protection makes use of a DC output rectifier. The current output from the rectifier is discharged to earth through anodes. The current, in turn, is picked up by the structure in contact with the earth (providing cathodic protection in the process) and returns through cable connections to the negative terminal of the rectifier. | ||
1 Overall, current requirements for this facility without electrical isolation can be estimated to be one thousand or more amperes. In addition to total current demand, the distribution of protective current is an important factor. Congested areas result in limited anode "throw". Piping under reinforced concrete slabs (i.e. turbine generator building) can be shielded from protective current-by-current pickup to the reinforcing rods. The reinforcing rods can also be electrically continuous to the buried piping. For this reason, distributed or linear anodes are generally a preferred choice for power plants if the cathodic protection system can be installed during plant "Electrical Grounding and cachodic protection Issues in Large Generating Stations", Materials Performance 40,11 (November 2001): p. 17 | Page 8 of 18 PCA ENGINEERING, INC. | ||
The installation of distributed type anodes after large plant construction can be cost prohibitive. | IPEC00220860 IPEC00220860 | ||
Deepwell cathodic protection systems are an alternate consideration after plant construction inasmuch as excavation can be minimized. | |||
However, as indicated, distribution of current must be carefully evaluated and all underground piping should be electrically continuous. | V. CRITERIA FOR CATHODIC PROTECTION The criteria for determining the adequacy of protection on a buried structure is defined in the NACE Recommended Practice SP0169-2008 entitled "Control of External Corrosion on Underground or Submerged Metallic Piping Systems". In essence, the requirements for steel structures are as follows: | ||
A. A negative voltage of at least 850 mv as measured between the structure and a saturated copper/copper sulfate reference cell contacting the earth directly over the structure. | |||
B. A negative polarized potential* of at least 850 mV relative to a saturated copper/copper sulfate reference cell. | |||
*Polarized Potential: The potential across the structure/electrolyte interface that is the sum of the corrosion potential and the cathodic polarization. | |||
Page 9 of 18 PCA ENGINEERING; INC. | |||
IPEC00220861 IPEC00220861 | |||
V. CRITERIA FOR CATHODIC PROTECTION (Cont'd) | |||
C. A minimum polarization voltage shift of 100 mV as measured between the structure and a saturated copper/copper sulfate reference cell contacting the earth directly over the structure. This polarization voltage shift shall be determined by interrupting the protective current and measuring the polarization decay. When the protective current is interrupted, an immediate voltage shift will occur. The voltage reading, after the immediate shift, shall be used as the base reading from which to measure polarization decay. | |||
VI. TEST RESULTS AND RECOMMENDATIONS The prior surveys of the Unit No. 2 sheet piling performed in 2006 and 2008 generally indicate satisfactory levels of cathodic protection were being provided to the structures (with some limitations of available test locations). The results of these surveys were furnished in a separate report. | |||
Page 10 of 18 PCA ENGINEERING, INC. | |||
IPEC00220862 IPEC00220862 | |||
VI. TEST RESULTS AND RECOMMENDATIONS (Cant' d) | |||
The structure to soil/water potential measurements obtained at various locations during this site investigation are as shown on the enclosed Corrosion Field Survey Data Table Nos. I, II and III. The data includes "as found" potential measurements of the various piping/structures and results of the change in potential due to the temporary addition of impressed current, where possible. As expected, the test data indicates all "as found" potential measurements for the piping are below the 850 millivolt criteria as an indication of satisfactory cathodic protection as described ln Section V of this report. This was to be expected as there is no dedicated cathodic protection on these structures. | |||
With an additional 100 amperes of impressed current applied during the survey, the Unit No. 2 circulating water piping showed potential shifts of less than 10 millivolts as compared to the as found potential. This demonstrates a very limited distribution of protective current and the Page 11 of 18 PCA ENGINEERING, INC. | |||
IPEC00220863 IPEC00220863 | |||
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd) significant load that the copper grounding system places on a cathodic protection system. The circulating water piping at Unit Nos. 2 and 3 were found to be electrically continuous to the plant copper grounding system, as expected. | |||
A review of the original cathodic protection plan drawings indicates the installation of distributed high silicon iron anodes for the intake structures and the sheet piling. These components were installed during plant construction. There is little historical operational data to indicate the level of effectiveness of the system. With the exception of the Unit No. 2 intake structure sheet piling and a sewage pipeline operating cathodic protection system, all other original cathodic protection systems have been removed and/or abandoned. | |||
The city water piping potentials are as shown on the enclosed Data Table III. The most significant finding of the field testing indicates a positive shift in the potentials of the city water piping where it crosses the Algonquin gas pipeline. This static stray current is Page 12 of 18 PCA ENGINEERING, INC. | |||
IPEC00220864 IPEC00220864 | |||
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd} | |||
caused by the impressed current system presently in service for the Algonquin pipeline. Stray current can result in serious corrosion at the point of current discharge from the "foreign" pipe. Impressed current demand testing utilized two steel bollards as temporary anodes near the Broadway storage tank and provided 2 amperes of current. | |||
This provided only some localized protection to the piping near the storage tank and reduced the magnitude of the effect of the stray current. | |||
The Diesel Generator Tank Nos. 21, 22 and 23 were found to be unprotected as there is no cathodic protection system associated with these structures. The TSC diesel tank was found to be of sti-P 3 construction and partially protected. Tanks of sti-P 3 construction include a high quality external coating, factory installed galvanic anodes and electrical isolation as a defense against corrosion. | |||
The APR tank could not be accessed as it was located within a vault identified as a confined space entry. | |||
Page 13 of 18 PCA ENGINEERING, INC. | |||
IPEC00220865 IPEC00220865 | |||
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd) | |||
Soil resistivity measurements were obtained at two (2) locations in proximity to the Unit No. 2 condensate piping and at two (2) locations in close proximity to the city water piping. The resistivity values are as shown on the attached Data Table No. III and range from 8,043 ohm/em to 63,195 ohm/em with an average value of 28,589 ohm/em. | |||
VII. DISCUSSION AND RECOMMENDATIONS Installation of a cathodic protection system during power plant construction can be cost effective and is generally easily installed prior to backfilling/grading. | |||
The installation of a cathodic protection system after plant construction can become difficult and generally expensive. This problem is exaggerated in the presence of subsurface rock as reported for this site. Impressed current system options include distributed anodes, linear anodes and anode deepwell systems. | |||
Connection of the copper grounding system to an impressed current system increases cathodic protection requirements by several order of magnitude. Bare copper structures are difficult to polarize as compared to steel Page 14 of 18 PCA ENGINEERING, INC. | |||
IPEC00220866 IPEC00220866 | |||
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) structures that can be well coated. Prior studies have indicated the current density required to polarize copper to an adequate potential necessary to protect a ferrous structure may be 10 to 20 times as high ~ on a per unit area basis - as the level required to polarize ferrous structures. 1 Overall, current requirements for this facility without electrical isolation can be estimated to be one thousand or more amperes. | |||
In addition to total current demand, the distribution of protective current is an important factor. Congested areas result in limited anode "throw". Piping under reinforced concrete slabs (i.e. turbine generator building) can be shielded from protective current-by-current pickup to the reinforcing rods. The reinforcing rods can also be electrically continuous to the buried piping. For this reason, distributed or linear anodes are generally a preferred choice for power plants if the cathodic protection system can be installed during plant "Electrical Grounding and cachodic protection Issues in Large Generating Stations", Materials Performance 40,11 (November 2001): | |||
: p. 17 Page 15 of 18 PCA ENGINEERING, INC. | |||
IPEC00220867 IPEC00220867 | |||
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) construction. The installation of distributed type anodes after large plant construction can be cost prohibitive. | |||
Deepwell cathodic protection systems are an alternate consideration after plant construction inasmuch as excavation can be minimized. However, as indicated, distribution of current must be carefully evaluated and all underground piping should be electrically continuous. | |||
Electrical continuity is generally lacking in applications where mechanical joint ductile or cast iron piping is utilized unless the joints are fitted with a bonding strap at time of installation. | Electrical continuity is generally lacking in applications where mechanical joint ductile or cast iron piping is utilized unless the joints are fitted with a bonding strap at time of installation. | ||
Based on the results of the testing and the complex configuration of power plants, a multi-phase plan will provide the most effective return. The following are suggested: | Based on the results of the testing and the complex configuration of power plants, a multi-phase plan will provide the most effective return. The following recou~endations are suggested: | ||
* As a priority, install a mitigation bond to eliminate/minimize stray current to the city water piping at the location that crosses the Algonquin gas pipeline. This will require joint communication and cooperation. The purpose of the bond is to provide a low resistance path between the foreign Page 16 of 18 PCA ENGINEERING, INC. | |||
* As a priority, install a mitigation bond to eliminate/minimize stray current to the city water piping at the location that crosses the Algonquin gas pipeline. | IPEC00220868 IPEC00220868 | ||
This will require joint communication and cooperation. | |||
The purpose of the bond is to provide a low resistance path between the foreign Page 16 of 18 PCA ENGINEERING, INC. IPEC00220868 VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) | VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) structure and the protected structure. An alternate method to a mitigation bond is the installation of sacrificial anodes at the crossing. The sacrificial anode provides a path where the collected current can leave the foreign structure with corrosion occurring at the anode rather than the foreign structure. | ||
An alternate method to a mitigation bond is the installation of sacrificial anodes at the crossing. | * Provide a progressive evaluation of cathodic protection needs for high priority piping services on a zone basis. | ||
The sacrificial anode provides a path where the collected current can leave the foreign structure with corrosion occurring at the anode rather than the foreign structure. | Although a distributed or linear anode system would be the best performance choice, its installation to an existing facility is likely not feasible. | ||
* Provide a progressive evaluation of cathodic protection needs for high priority piping services on a zone basis. Although a distributed or linear anode system would be the best performance choice, its installation to an existing facility is likely not feasible. | Therefore, a deepwell anode system would offer the most feasible approach. Once installed, an assessment and evaluation of the system effectiveness can be compared to the application for additional piping zones. | ||
Therefore, a deepwell anode system would offer the most feasible approach. | Page 17 of 18 PCA ENGINEERING, INC. | ||
Once installed, an assessment and evaluation of the system effectiveness can be compared to the application for additional piping zones. Page 17 of 18 PCA ENGINEERING, INC. IPEC00220869 VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) | IPEC00220869 IPEC00220869 | ||
* The implementation of an inspection program based on | |||
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) | |||
* | * The implementation of an inspection program based on API 570 can identify high priority zones. These zones could be determined by excavation and inspection of existing pipe. Upon excavation, an ultrasonic thickness measurement of the pipe wall and coating evaluation could be made. | ||
WILLIAM J. SIMPSON NACE CATHODIC PROTECTION SPECIALIST NO. 3634 PCA ENGINEERING, INC. | |||
: INDIAN POINT UNIT #2 POTENTIAL MEASUREMENT TABLE I DATE OBTAINED: | WJS:lms Page 18 of 18 PCA ENGINEERING, INC. | ||
OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF I SURVEYED BY: W. SIMPSON I D. RAW A UNLESS OTHERWISE SHOWN LOCATION FOUND OFF IN CR. REMOTE COMMENTS CIRCULATING WATER PIPE AS FOUND-RECTA. | IPEC00220870 IPEC00220870 | ||
WATERSIDE 15.8 V-84 A. PIPE RISER # 21 504 491 512 443 AS FOUND-RECT B. LANDSIDE 12.9 V-39.4 A PIPE RISER # 22 532 525 535 443 PIPE RiSER # 23 580 576 569 443 TEMP. fNCREASE RECTA TO 24.4 V --148 A. PIPE RISER # 24 594 589 573 445 TEMP. INCREASE RECT B TO 23.3 V-74 A. PIPE RISER # 25 559 549 543 445 PIPE RISER # 26 613 575 607 445 NORTH SERVICE WATER PUMPS 463 466 445 GROUND CABLE 431 RECTIFIER A WATERSIDE NEGATIVE LUG 445 RECTIFIER B LANDS IDE NEGATIVE LUG 430 CONDENSATE PIPING AT TANK 296 248 GROUND CABLE AT TANK 328 DIESEL GENERATOR BUILDING TANK2l FOST 140 NORTif TANK22 FOST 130 MIDDLE TANK23 FOST 130 SOUTH --*-*-*- | |||
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OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF 1 SURVEYED BY: W. SIMPSON I D. RA WA UNLESS OTHERWISE SHOWN LOCATION FOUND REMOTE COMMENTS CIRCULATING WATER PIPE PIPE RISER # 31 347 159 SOUTH PIPE RISER # 32 279 159 PIPE RISER # 33 249 159 PIPE RISER # 34 305 160 PIPE RISER # 35 268 159 PIPE RISER # 36 343 160 NORTH SERVICE WATER VENT #34,35,36 232 159 SERVICE WATER VENT #31 ,32,33 236 159 GROUND CABLE AT BUILDING 158 SHEET PILE DISCHARGE 263 N s E w c TSC DIESEL UNDERGROUND TANK 888 792 --885 853 CONCRETE 755 718 865 662 --SOIL | 0 0 | ||
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: CITY WATER PIPING POTENTIAL MEASUREMENT TABLE IV DATE OBTAINED: | PCA ENGINEERING, INC. | ||
OCTOBER 15,2008 NEGATIVE MILLIVOLTS SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA UNLESS OTHERWISE SHOWN LOCATION AS FOUND ON OFF BROADWAY PUMP HOUSE 369 460 411 NO ISOLATION CITY & PLANT PIPING SOUfH MANWAY OF TANK 363 1586 710 TEMPORARY RECTIFIER65 VOLTS, 2.12 AMP AT GATE 433 9590 1562 115' WEST OF GATE 398 1349 719 FIRE HYDRANT 234 580 439 EAST PIPELINE MARKER +200/400 +20/180 +20/180 WEST PIPELINE MARKER 0/+400 +200/300 +200/300 CONCRETE BARRIER 120/150 100 100 OVERLOOK ROAD 333 270 270 FIRE HUDRANT UPPER PARKING LOT 383 367 367 NEXT TO POLE IN PARKING LOT 317 304 304 NEAR STAIRWAY TOP OF HILL 272 292 292 | ....... 430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES | ||
""0 m () 0 0 0 | * Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL | ||
: PIPING TABLE IV DATE OBTAINED: | * PCA JOB NO: 28457 STRUCTURE : INDIAN POINT UNIT #2 POTENTIAL MEASUREMENT TABLE I DATE OBTAINED: OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF I SURVEYED BY: W. SIMPSON I D. RAW A UNLESS OTHERWISE SHOWN LOCATION FOUND OFF IN CR. REMOTE COMMENTS CIRCULATING WATER PIPE AS FOUND-RECTA. WATERSIDE 15.8 V- 84 A. | ||
OCTOBER 7, 2008 UNLESS OTHERWISE SHOWN SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA LOCATION 5FT lOFT. 15FT. CONDENSATE PIPING -UNIT #2 LOCATION#! | PIPE RISER # 21 504 491 512 443 AS FOUND- RECT B. LANDSIDE 12.9 V-39.4 A PIPE RISER # 22 532 525 535 443 PIPE RiSER # 23 580 576 569 443 TEMP. fNCREASE RECTA TO 24.4 V -- 148 A. | ||
30,640 31,598 8,043 Pl-1=6 LOCATION#2 63,195 28,725 11,490 PH= 5.9 CITY WATER PIPING UPPER PARKING LOT NEAR STAIRWAY 30,161 36,385 40,215 12' SE OF UGHT POLE MOVING EAST OVERLOOK ROAD 24,895 21,065 16,660 3' SOUTH OF FIRE LANE SIGN MOVING SOUTH | PIPE RISER # 24 594 589 573 445 TEMP. INCREASE RECT B TO 23.3 V- 74 A. | ||
""0 m () 0 0 0 00 | PIPE RISER # 25 559 549 543 445 PIPE RISER # 26 613 575 607 445 NORTH SERVICE WATER PUMPS 463 466 445 GROUND CABLE 431 RECTIFIER A WATERSIDE NEGATIVE LUG 445 RECTIFIER B LANDS IDE NEGATIVE LUG 430 CONDENSATE PIPING AT TANK 296 248 GROUND CABLE AT TANK 328 DIESEL GENERATOR BUILDING TANK2l FOST 140 NORTif TANK22 FOST 130 MIDDLE | ||
W.J.S. | ""0 m TANK23 FOST 130 SOUTH | ||
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I'V 430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL PCA JOB NO: 28457 STRUCTURE : INDIAN POINT UNIT #3 POTENTIAL MEASUREMENT TABLE II DATE OBTAINED: OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF 1 SURVEYED BY: W. SIMPSON I D. RA WA UNLESS OTHERWISE SHOWN LOCATION FOUND REMOTE COMMENTS CIRCULATING WATER PIPE PIPE RISER # 31 347 159 SOUTH PIPE RISER # 32 279 159 PIPE RISER # 33 249 159 PIPE RISER # 34 305 160 PIPE RISER # 35 268 159 PIPE RISER # 36 343 160 NORTH SERVICE WATER VENT #34,35,36 232 159 SERVICE WATER VENT #31 ,32,33 236 159 GROUND CABLE AT BUILDING -~ 158 SHEET PILE DISCHARGE 263 N s E w c TSC DIESEL UNDERGROUND TANK 888 792 -- 885 853 CONCRETE 755 718 865 662 -- SOIL | |||
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V> 430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL PCA JOB NO: 28457 STRUCTURE : CITY WATER PIPING POTENTIAL MEASUREMENT TABLE IV DATE OBTAINED: OCTOBER 15,2008 NEGATIVE MILLIVOLTS SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA UNLESS OTHERWISE SHOWN LOCATION AS FOUND ON OFF BROADWAY PUMP HOUSE 369 460 411 NO ISOLATION CITY & PLANT PIPING SOUfH MANWAY OF TANK 363 1586 710 TEMPORARY RECTIFIER65 VOLTS, 2.12 AMP AT GATE 433 9590 1562 115' WEST OF GATE 398 1349 719 FIRE HYDRANT 234 580 439 EAST PIPELINE MARKER +200/400 +20/180 +20/180 WEST PIPELINE MARKER 0/+400 +200/300 +200/300 CONCRETE BARRIER 120/150 100 100 OVERLOOK ROAD 333 270 270 FIRE HUDRANT UPPER PARKING LOT 383 367 367 NEXT TO POLE IN PARKING LOT 317 304 304 NEAR STAIRWAY TOP OF HILL 272 292 292 | |||
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430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES Pompton Lakes, NJ 07442 OWNER: ENTERGY SOIL RESISTIVITY MEASUREMENT PCA JOB NO: 28457 STRUCTURE : PIPING OHM-CM~ | |||
TABLE IV DATE OBTAINED: OCTOBER 7, 2008 UNLESS OTHERWISE SHOWN SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA LOCATION 5FT lOFT. 15FT. | |||
CONDENSATE PIPING -UNIT #2 LOCATION#! 30,640 31,598 8,043 Pl-1=6 LOCATION#2 63,195 28,725 11,490 PH= 5.9 CITY WATER PIPING UPPER PARKING LOT NEAR STAIRWAY 30,161 36,385 40,215 12' SE OF UGHT POLE MOVING EAST OVERLOOK ROAD 24,895 21,065 16,660 3' SOUTH OF FIRE LANE SIGN MOVING SOUTH | |||
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.._..- :r 430 Montdair Ave. Pompton Lakes, NJ. ENTERGY NUCLEAR OPERATIONS, INC. 0 INDIAN POINT ENERCY CENTER rawmg N t um er. | |||
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INDIAN POINT ENERGY CENTER SOll RESISTIVITY TEST LOCATION PCA ENG!NEER!NG1 INC. 450 BROADWAY BUCHANAN, NY 10511 . . | |||
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TEL {973) 616-4501 IN!)]AN POINT ENERGY CENlER Drowmg Number: A.U.Z. | |||
450 BROADWAY BUCHANAN, NY 10511 AW--28457--03 Date: 12-30-08 | |||
**------*---*****--*'"'"'""""~"'" ____ ~**-}} |
Latest revision as of 20:33, 6 February 2020
ML113530077 | |
Person / Time | |
---|---|
Site: | Indian Point ![]() |
Issue date: | 12/16/2011 |
From: | Entergy Nuclear Operations, PCA Engineering |
To: | Atomic Safety and Licensing Board Panel |
SECY RAS | |
Shared Package | |
ML113530062 | List: |
References | |
RAS 21566, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
Download: ML113530077 (27) | |
Text
NYS000178 Submitted: December 16, 2011 ATTACHMENT 9.1 ENGINEERING REPORT COVER SHEET & INSTRUCTIONS Engineering Report No. IP-RPT Rev 0 00011 Page of
-- Entergy ENTERGY NUCLEAR Engineering Report Cover Sheet Engineering Report
Title:
Corrosion/Cathodic Protection Field Survey and Assessment of Underground Structures at Indian Point Energy Center Unit Nos. 2 and 3 during October 2008 Engineering Report Type:
New GJ Revision 0 Cancelled 0 Superseded 0 Applicable Site(s)
IPI GJ IP2 GJ IP3 GJ JAF 0 PNPS 0 VY 0 WPO 0 ANO! 0 AN02 0 0 0 0 0 ECH GGNS RBS WF3 PLP 0 DRN No. ON/A; 0 __
Report Origin: 0 Entergy GJ Vendor Vendor Document No.: PCA Job No. 28457 Quality-Related: 0 Yes GJ No Prepared by: _ _ _ _ _ __::P::..,C::.:A~E:.:.:n:2g:.:.:in:.:.ee::..::r..:.:in;:;;gu.,.: :In::. : c:.:. . - . , - , - - - - - Date: 12/2/08 Responsible Engineer (Print Name/Sign)
Not Design Veri tied! _ _ _ __:.D=:,e:.::s;:;;ig~:.:n~V:....:e::.r::..::if::..::lc-=at:.:.:io:..:n::._l:.:..s..:.:n:.::.o::._tR:.: .:. :eq:I.;u:.:.:ir:.: e; ; d_ _ __ Date: Required Design Verifier (if required) (Print Name/Sign)
Reviewed by:
Not Date: Required
- For ASME Section XI Code Program plans per ENN-DC-120. if require EN-DC-147 REV 3 IPEC00220850 IPEC00220850
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....... SHEET1 OF 1 A~~ Entergy Engineering Report Technical Review Comments and Resolutions Form Engineering Rev.
Title:
Corrosion/Cathodic Protection Field Survey and Assessment of Report Number IP-RPT 00011 0 Underground Structures at Indian Point Energy Center Unit Nos. 2 and 3 during October 2008 Quality Related: DYes [8J No Special Notes or Instructions: None Comment Section/ Page No. Review Comment Response/Resolution Preparer's !
Number Accept Initials No N/A Comments I 2126/09 I N/A Verified/Reviewed By:
Site/Department:
Christopher A Ingrassia IPEC I System Engineering l Ph. 914-271-7047 Date Resolved By:
Date:
I
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Prepared fcr:
Entergy Nuclear Operations, Inc.
Indian Point Energy Center 450 Broadway Buchanan, NY 10511 Corrosion I Catl10dic Prolection F'leld Survey and - d of Underground StiUctLres at Indian Point Energy Center Unit Nos. 2 and 3 Prepa"ed by:
PCA Engineering, Inc.
430 Montdar Avenue P.O. Box196 Pompton Lakes, NJ 07442 PCA Job No. 28457 November 10, 2008 Revised December 2, 2008 IPEC00220852 IPEC00220852
I. INTRODUCTION During the month of October 2008, PCA Engineering, Inc. personnel performed a corrosion/cathodic protection field survey and assessment of the underground structures associated with the Entergy Nuclear Operations Indian Point Unit Nos. 2 and 3 Facility located in Buchanan, New York.
This included a review of site drawings and a site survey. The field survey procedures essentially consisted of structure-to-soil potential measurements, electrical isolation testing, temporary impressed current testing and soil resistivity measurements.
II. SITE DESCRIPTION The operating systems at the Indian Point Facility consist of Unit Nos. 2 and 3, estimated to be in operation since approximately 1968. The underground piping and structures under consideration as part of this investigation include the following:
- Intake Structure, including sheet piling
- Circulating Water Piping
- Service Water Piping Page 1 of 18 PCA ENGINEERING, INC.
IPEC00220853 IPEC00220853
II. SITE DESCRIPTION {Cont'd)
- Condensate Piping
- City Water Piping
- Underground Diesel Generator Tanks The majority of the underground piping is reported to be welded carbon steel. The construction specifications called for external coal tar coating or tape wrapped pipe.
It is unknown if the piping was inspected for quality and coating holidays at the time of installation. The service water and city water service piping are also reported to be cement lined.
The intake structure consists of a sheet piling wall located on the north and south sides of Unit No. 2 and Unit No. 3. An additional segment of sheet pile wall also extends south of Unit No. 3.
The circulating water piping consists of six (6) 84-inch underground pipes for each of the two units. The service water piping primarily consists of two (2) 24-inch underground pipes with some smaller runs of piping for each of the two units.
Page 2 of 18 PCA ENGINEERING, INC.
IPEC00220854 IPEC00220854
II. SITE DESCRIPTION (Cont'd)
An impressed current cathodic protection system was installed during power plant construction for the intake structures and the circulating/service water piping. The majority of these systems have been removed or are out of service, with the exception of that for the intake structure sheet piling associated with Unit No. 2. An impressed current cathodic protection system is also in place for the Unit No. 1 main dock, but is not a part of this investigation. The original cathodic protection design was not based upon providing electrical isolation of the protected underground piping from the unprotected copper grounding grid or other metallic structures (i.e. building steel, aboveground piping, reinforcing steel) .
The underground portion of the Unit No. 2 condensate piping is located between the on-grade Condensate Storage Tank and Auxiliary Feed Pump Building and consists of a 12, 10 and 8-inch carbon steel coated pipe. The corresponding lines at Unit No. 3 are aboveground (heat traced, insulated and jacketed).
Page 3 of 18 PCA ENGINEERING, INC.
IPEC00220855 IPEC00220855
II. SITE DESCRIPTION (Cont'd)
The applicable portion of the City Water Piping consists of a 16-inch steel cement lined pipe located between the on-grade water storage tank at Broadway and the Air Monitor House. The pipe is then installed within a utility tunnel. The city water piping crosses the Algonquin Gas Pipeline.
The tanks at the Unit No. 2 Diesel Generator Building consist of three (3) 7,700-gallon capacity underground storage tanks. These tanks are mounded and reported to be backfilled with sand. Two (2) underground diesel tanks associated with Unit No. 3 were also investigated. This consisted of a TSC diesel tank and an APR diesel tank. The TSC tank was found to be of sti-P3 (Steel Tank Institute -
corrosion protected) construction and the APR tank was observed to be located in a concrete vault.
Page 4 of 18 PCA ENGINEERING, INC.
IPEC00220856 IPEC00220856
III. TEST PROCEDURES Pipe-to-soil potential measurements were obtained using a Fluke Model 77 Digital Voltmeter and a portable copper/copper sulfate reference electrode. Temporary impressed current testing was performed using a portable 80-volt, 8-amp rectifier. Two (2) existing rectifiers at Unit No. 2 were also employed for the testing.
Soil resistivity readings were obtained using the Wenner 4-Pin Method in conjunction with a Nilsson Model 400 Soil Resistance Meter. Resistivity measurements were obtained at representative depths of 5 feet, 10 feet and 15 feet.
IV. CORROSION/CATHODIC PROTECTION - GENERAL
- 1. Corrosion of Buried Structures Corrosion is an electrochemical process by which steel and other metals attempt to return to their natural ore condition. In this process, the metal lS corroded by discharges of electrical metallic ions to earth.
There are many different causes of corrosion, among which the most common are:
Page 5 of 18 PCA ENGINEERING, INC.
IPEC00220857 IPEC00220857
IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd) a) Dissimilar metals that are electrically tied together b) Dissimilar soils c) Differential aeration d) Anaerobic bacteria e) Outside sources of D.C. current Power plants generally consist of a congested underground environment consisting of multiple service piping in the presence of an extensive grounding network. The existence of underground piping of various materials of construction (i.e. steel, ductile iron) in the presence of a bare copper grounding network is conducive to galvanic corrosion from dissimilar metals. The corrosion is detrimental to the ferrous piping materials as it is anodic in the presence of copper. Any breaks or holidays in the pipe coating are conducive to a high ratio of anode to cathode. This can lead to accelerated rates of corrosion in steel and ferrous materials, particularly if scil resistivity is low.
Page 6 of 18 PCA ENGINEERING, INC.
IPEC00220858 IPEC00220858
IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd)
Soil resistivity measurements indicate the relative ability of the earth to carry electrical currents. Corrosiveness of soil is generally an inverse function of the resistivity. Lower resistivity soils are generally considered to be more corrosive than soils of higher resistivity.
The general classifications of soil resistivity relating to the degree of corrosivity are as follows:
a) 0 to 2,000 ohm/em- extremely corrosive b) 2,000 to 10,000 ohm/em- moderately corrosive c) 10,000 to 30,000 ohm/em- mildly corrosive d) 30,000 ohm/em and over- progressively less corrosive These classifications are general. Under certain conditions, severe corrosion can occur in the higher resistivity soil. Large variations in resistivity indicate the existence of variations in soil composition, and such variations can be conducive to the creation of galvanic corrosion activity on an underground structure.
Page 7 of 18 PCA ENGINEERING, INC.
IPEC00220859 IPEC00220859
IV. CORROSION/CATHODIC PROTECTION- GENERAL (Cont'd)
- 2. Cathodic Protection In order to stop corrosion, the natural flow of current from a metallic structure to earth has to be stopped. This can be accomplished by the use of sacrificial anodes that supply current to earth, which is picked up by the structure, thus reversing the flow of current and stopping the corrosion process; this lS called cathodic protection.
Sacrificial anodes, such as magnesium, make use of the voltage difference between the structure metal and the anode material. The anode is always more negative than the structure; therefore, the flow of current through the wire connection is from structure to anode and the flow of current through the electrolyte (earth) is from anode to structure.
The impressed current type of cathodic protection makes use of a DC output rectifier. The current output from the rectifier is discharged to earth through anodes. The current, in turn, is picked up by the structure in contact with the earth (providing cathodic protection in the process) and returns through cable connections to the negative terminal of the rectifier.
Page 8 of 18 PCA ENGINEERING, INC.
IPEC00220860 IPEC00220860
V. CRITERIA FOR CATHODIC PROTECTION The criteria for determining the adequacy of protection on a buried structure is defined in the NACE Recommended Practice SP0169-2008 entitled "Control of External Corrosion on Underground or Submerged Metallic Piping Systems". In essence, the requirements for steel structures are as follows:
A. A negative voltage of at least 850 mv as measured between the structure and a saturated copper/copper sulfate reference cell contacting the earth directly over the structure.
B. A negative polarized potential* of at least 850 mV relative to a saturated copper/copper sulfate reference cell.
- Polarized Potential: The potential across the structure/electrolyte interface that is the sum of the corrosion potential and the cathodic polarization.
Page 9 of 18 PCA ENGINEERING; INC.
IPEC00220861 IPEC00220861
V. CRITERIA FOR CATHODIC PROTECTION (Cont'd)
C. A minimum polarization voltage shift of 100 mV as measured between the structure and a saturated copper/copper sulfate reference cell contacting the earth directly over the structure. This polarization voltage shift shall be determined by interrupting the protective current and measuring the polarization decay. When the protective current is interrupted, an immediate voltage shift will occur. The voltage reading, after the immediate shift, shall be used as the base reading from which to measure polarization decay.
VI. TEST RESULTS AND RECOMMENDATIONS The prior surveys of the Unit No. 2 sheet piling performed in 2006 and 2008 generally indicate satisfactory levels of cathodic protection were being provided to the structures (with some limitations of available test locations). The results of these surveys were furnished in a separate report.
Page 10 of 18 PCA ENGINEERING, INC.
IPEC00220862 IPEC00220862
VI. TEST RESULTS AND RECOMMENDATIONS (Cant' d)
The structure to soil/water potential measurements obtained at various locations during this site investigation are as shown on the enclosed Corrosion Field Survey Data Table Nos. I, II and III. The data includes "as found" potential measurements of the various piping/structures and results of the change in potential due to the temporary addition of impressed current, where possible. As expected, the test data indicates all "as found" potential measurements for the piping are below the 850 millivolt criteria as an indication of satisfactory cathodic protection as described ln Section V of this report. This was to be expected as there is no dedicated cathodic protection on these structures.
With an additional 100 amperes of impressed current applied during the survey, the Unit No. 2 circulating water piping showed potential shifts of less than 10 millivolts as compared to the as found potential. This demonstrates a very limited distribution of protective current and the Page 11 of 18 PCA ENGINEERING, INC.
IPEC00220863 IPEC00220863
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd) significant load that the copper grounding system places on a cathodic protection system. The circulating water piping at Unit Nos. 2 and 3 were found to be electrically continuous to the plant copper grounding system, as expected.
A review of the original cathodic protection plan drawings indicates the installation of distributed high silicon iron anodes for the intake structures and the sheet piling. These components were installed during plant construction. There is little historical operational data to indicate the level of effectiveness of the system. With the exception of the Unit No. 2 intake structure sheet piling and a sewage pipeline operating cathodic protection system, all other original cathodic protection systems have been removed and/or abandoned.
The city water piping potentials are as shown on the enclosed Data Table III. The most significant finding of the field testing indicates a positive shift in the potentials of the city water piping where it crosses the Algonquin gas pipeline. This static stray current is Page 12 of 18 PCA ENGINEERING, INC.
IPEC00220864 IPEC00220864
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd}
caused by the impressed current system presently in service for the Algonquin pipeline. Stray current can result in serious corrosion at the point of current discharge from the "foreign" pipe. Impressed current demand testing utilized two steel bollards as temporary anodes near the Broadway storage tank and provided 2 amperes of current.
This provided only some localized protection to the piping near the storage tank and reduced the magnitude of the effect of the stray current.
The Diesel Generator Tank Nos. 21, 22 and 23 were found to be unprotected as there is no cathodic protection system associated with these structures. The TSC diesel tank was found to be of sti-P 3 construction and partially protected. Tanks of sti-P 3 construction include a high quality external coating, factory installed galvanic anodes and electrical isolation as a defense against corrosion.
The APR tank could not be accessed as it was located within a vault identified as a confined space entry.
Page 13 of 18 PCA ENGINEERING, INC.
IPEC00220865 IPEC00220865
VI. TEST RESULTS AND RECOMMENDATIONS (Cont'd)
Soil resistivity measurements were obtained at two (2) locations in proximity to the Unit No. 2 condensate piping and at two (2) locations in close proximity to the city water piping. The resistivity values are as shown on the attached Data Table No. III and range from 8,043 ohm/em to 63,195 ohm/em with an average value of 28,589 ohm/em.
VII. DISCUSSION AND RECOMMENDATIONS Installation of a cathodic protection system during power plant construction can be cost effective and is generally easily installed prior to backfilling/grading.
The installation of a cathodic protection system after plant construction can become difficult and generally expensive. This problem is exaggerated in the presence of subsurface rock as reported for this site. Impressed current system options include distributed anodes, linear anodes and anode deepwell systems.
Connection of the copper grounding system to an impressed current system increases cathodic protection requirements by several order of magnitude. Bare copper structures are difficult to polarize as compared to steel Page 14 of 18 PCA ENGINEERING, INC.
IPEC00220866 IPEC00220866
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) structures that can be well coated. Prior studies have indicated the current density required to polarize copper to an adequate potential necessary to protect a ferrous structure may be 10 to 20 times as high ~ on a per unit area basis - as the level required to polarize ferrous structures. 1 Overall, current requirements for this facility without electrical isolation can be estimated to be one thousand or more amperes.
In addition to total current demand, the distribution of protective current is an important factor. Congested areas result in limited anode "throw". Piping under reinforced concrete slabs (i.e. turbine generator building) can be shielded from protective current-by-current pickup to the reinforcing rods. The reinforcing rods can also be electrically continuous to the buried piping. For this reason, distributed or linear anodes are generally a preferred choice for power plants if the cathodic protection system can be installed during plant "Electrical Grounding and cachodic protection Issues in Large Generating Stations", Materials Performance 40,11 (November 2001):
- p. 17 Page 15 of 18 PCA ENGINEERING, INC.
IPEC00220867 IPEC00220867
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) construction. The installation of distributed type anodes after large plant construction can be cost prohibitive.
Deepwell cathodic protection systems are an alternate consideration after plant construction inasmuch as excavation can be minimized. However, as indicated, distribution of current must be carefully evaluated and all underground piping should be electrically continuous.
Electrical continuity is generally lacking in applications where mechanical joint ductile or cast iron piping is utilized unless the joints are fitted with a bonding strap at time of installation.
Based on the results of the testing and the complex configuration of power plants, a multi-phase plan will provide the most effective return. The following recou~endations are suggested:
- As a priority, install a mitigation bond to eliminate/minimize stray current to the city water piping at the location that crosses the Algonquin gas pipeline. This will require joint communication and cooperation. The purpose of the bond is to provide a low resistance path between the foreign Page 16 of 18 PCA ENGINEERING, INC.
IPEC00220868 IPEC00220868
VII. DISCUSSION AND RECOMMENDATIONS (Cont'd) structure and the protected structure. An alternate method to a mitigation bond is the installation of sacrificial anodes at the crossing. The sacrificial anode provides a path where the collected current can leave the foreign structure with corrosion occurring at the anode rather than the foreign structure.
- Provide a progressive evaluation of cathodic protection needs for high priority piping services on a zone basis.
Although a distributed or linear anode system would be the best performance choice, its installation to an existing facility is likely not feasible.
Therefore, a deepwell anode system would offer the most feasible approach. Once installed, an assessment and evaluation of the system effectiveness can be compared to the application for additional piping zones.
Page 17 of 18 PCA ENGINEERING, INC.
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VII. DISCUSSION AND RECOMMENDATIONS (Cont'd)
- The implementation of an inspection program based on API 570 can identify high priority zones. These zones could be determined by excavation and inspection of existing pipe. Upon excavation, an ultrasonic thickness measurement of the pipe wall and coating evaluation could be made.
WILLIAM J. SIMPSON NACE CATHODIC PROTECTION SPECIALIST NO. 3634 PCA ENGINEERING, INC.
WJS:lms Page 18 of 18 PCA ENGINEERING, INC.
IPEC00220870 IPEC00220870
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- Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL
- PCA JOB NO: 28457 STRUCTURE : INDIAN POINT UNIT #2 POTENTIAL MEASUREMENT TABLE I DATE OBTAINED: OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF I SURVEYED BY: W. SIMPSON I D. RAW A UNLESS OTHERWISE SHOWN LOCATION FOUND OFF IN CR. REMOTE COMMENTS CIRCULATING WATER PIPE AS FOUND-RECTA. WATERSIDE 15.8 V- 84 A.
PIPE RISER # 21 504 491 512 443 AS FOUND- RECT B. LANDSIDE 12.9 V-39.4 A PIPE RISER # 22 532 525 535 443 PIPE RiSER # 23 580 576 569 443 TEMP. fNCREASE RECTA TO 24.4 V -- 148 A.
PIPE RISER # 24 594 589 573 445 TEMP. INCREASE RECT B TO 23.3 V- 74 A.
PIPE RISER # 25 559 549 543 445 PIPE RISER # 26 613 575 607 445 NORTH SERVICE WATER PUMPS 463 466 445 GROUND CABLE 431 RECTIFIER A WATERSIDE NEGATIVE LUG 445 RECTIFIER B LANDS IDE NEGATIVE LUG 430 CONDENSATE PIPING AT TANK 296 248 GROUND CABLE AT TANK 328 DIESEL GENERATOR BUILDING TANK2l FOST 140 NORTif TANK22 FOST 130 MIDDLE
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I'V 430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL PCA JOB NO: 28457 STRUCTURE : INDIAN POINT UNIT #3 POTENTIAL MEASUREMENT TABLE II DATE OBTAINED: OCTOBER 2, 2008 NEGATIVE MILLIVOLTS SHEET l OF 1 SURVEYED BY: W. SIMPSON I D. RA WA UNLESS OTHERWISE SHOWN LOCATION FOUND REMOTE COMMENTS CIRCULATING WATER PIPE PIPE RISER # 31 347 159 SOUTH PIPE RISER # 32 279 159 PIPE RISER # 33 249 159 PIPE RISER # 34 305 160 PIPE RISER # 35 268 159 PIPE RISER # 36 343 160 NORTH SERVICE WATER VENT #34,35,36 232 159 SERVICE WATER VENT #31 ,32,33 236 159 GROUND CABLE AT BUILDING -~ 158 SHEET PILE DISCHARGE 263 N s E w c TSC DIESEL UNDERGROUND TANK 888 792 -- 885 853 CONCRETE 755 718 865 662 -- SOIL
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V> 430 Montclair Avenue, P.O. Box 196 CORROSION FIELD SURVEY DATA AND TABLES Pompton Lakes, NJ 07442 OWNER: ENTERGY STRUCTURE TO SOIL PCA JOB NO: 28457 STRUCTURE : CITY WATER PIPING POTENTIAL MEASUREMENT TABLE IV DATE OBTAINED: OCTOBER 15,2008 NEGATIVE MILLIVOLTS SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA UNLESS OTHERWISE SHOWN LOCATION AS FOUND ON OFF BROADWAY PUMP HOUSE 369 460 411 NO ISOLATION CITY & PLANT PIPING SOUfH MANWAY OF TANK 363 1586 710 TEMPORARY RECTIFIER65 VOLTS, 2.12 AMP AT GATE 433 9590 1562 115' WEST OF GATE 398 1349 719 FIRE HYDRANT 234 580 439 EAST PIPELINE MARKER +200/400 +20/180 +20/180 WEST PIPELINE MARKER 0/+400 +200/300 +200/300 CONCRETE BARRIER 120/150 100 100 OVERLOOK ROAD 333 270 270 FIRE HUDRANT UPPER PARKING LOT 383 367 367 NEXT TO POLE IN PARKING LOT 317 304 304 NEAR STAIRWAY TOP OF HILL 272 292 292
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TABLE IV DATE OBTAINED: OCTOBER 7, 2008 UNLESS OTHERWISE SHOWN SHEET 1 OF 1 SURVEYED BY: W. SIMPSON I D. RAWA LOCATION 5FT lOFT. 15FT.
CONDENSATE PIPING -UNIT #2 LOCATION#! 30,640 31,598 8,043 Pl-1=6 LOCATION#2 63,195 28,725 11,490 PH= 5.9 CITY WATER PIPING UPPER PARKING LOT NEAR STAIRWAY 30,161 36,385 40,215 12' SE OF UGHT POLE MOVING EAST OVERLOOK ROAD 24,895 21,065 16,660 3' SOUTH OF FIRE LANE SIGN MOVING SOUTH
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