ML17157A421

Analysis of Pitting Corrosion Failures in ESW Sys RHR Lube Oil Coolers & RCIC Pump Room Unit Coolers at Susquehanna Steam Electric Station.

ML17157A421
Person / Time
Site:	Susquehanna
Issue date:	08/31/1990
From:	THOMAS M. LARONGE, INC.
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ML17157A422	List: ML17157A421 ML18030A369
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NUDOCS 9011190331
Download: ML17157A421 (200)

Text

Thomos M. Laronge, In(-.

10439 N.E. FOURTH PLAIN ROA0 ~ P.O. BOX 4448 ~ VANCOUVER, WA 98662 ~ (206) 254-1213 ~ FAX (206) 896-2106 September 10, 1990 ORI INAL ENT BY FEDERAL EXPRES PENNSYLVANIAPOWER & LIGHT COMPANY Two North Ninth Street Allentown, PA 18101-1179 Attention: Mr. Raymond S. Tombaugh, Project Engineer

SUBJECT:

REQUESTED REVISIONS TO FINAL REPORT ON ESW RHR LUBE OIL COOLER FAILURE ANALYSIS T.M.L. 197-90-002

Dear Mr. Tombaugh,

We are pleased to provide the attached replacement pages for our report T.M.L. 197-90-002, containing the editorial corrections and suggestions provided by you and your co-workers during our meeting on September 7, 1990.

We appreciate your input and hope that the report, as corrected, will be satisfactory. Please do not hesitate to call if you have any further questions.

Best regards,

.~c .c<

Arthur J. Freedman,

~

Executive Vice President

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Thomas M. Laronge, President AJF/TML:dh Enc: A/S 9011190331 901i12 PDR ADOCK 05000337 PDC P 4 Quo,lity for Industry

Thomas M. Laronge, Inc.

A KN WLED EMENT The work described in this report, particularly the work on-site and at PP&L's. Hazleton Laboratory and Allentown ofQces, could not have been accomplished without the wholehearted support and cooperation of PP@L personnel. The writers wish to express their appreciation for the time, effort and courtesies extended to us during this proj'ect. We also wish to express our special thanks to the following individuals, listed in alphabetical order, for their extra help beyond the call of duty:

D. P. Dunn D. J. Morgan T. J. Pensock W. J. Rhoades R. S. Tombaugh L. E. Willertz Page i

Thomos M. Laronge, Inc.

TABLE F NTE Acknowledgement Table of Contents Introduction Conclusions Results of Inspections 6 List of Inspected Equipment 6 Inspection Methods 6 Physical Measurements and Observations 8 RHR Lube Oil Coolers 8 RCIC Pump Room Unit Coolers 12 ESW Supply Line to RCIC lE-228B 14 Other Inspections 14 Discussion of Measurements and Inspections 15 Analyses of Deposits and Metal Surfaces 17 Analytical Methods 17 ICAP and Chemical Analyses of Deposits 18 SEM/EDS Analyses of Deposits 20 Microbiological Analyses 23 Discussion of Analytical Results 25 ESW System Chemistry and Operations 27 ESW Chemistry 27 ESW and RHR Pump Operations 28 System Operations 28 The ESW Spray Pond 29 ESW and RHR Pump Run Times 30 RHR Lube Oil Cooling Water Flow Velocities 32 Page ii

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Root Cause Failure Analysis 35 Summary 35 Pit Initiation 36 Pit Propagation 37 Effects of Sulfur, Iron and Manganese in Deposits 38 Comparison of RHR Coolers (Copper) and RCIC Coolers (Cupronickel) 40 Appendix 42 Bibliography 43 List of Tables 45 List of Figures 61 List of Photographs 92 Preliminary Report Page iii

Thomos M. Loronge, Inc.

INTR D TI N On May 28, 1990, a leak occurred in the RHR 2E-217C Motor Oil Cooler at the Pennsylvania Power and Light (PP&L) Susquehanna Steam Electric Station (SSES). This leak forced a shutdown of Unit 1 and a delay in startup of Unit 2 until all RHR motor oil cooling coils could be replaced, other critical heat exchangers using emergency service water (ESW) for cooling could be inspected, the root cause of the problem. determined and the potential for similar failures in related equipment evaluated.

Thomas M. Laronge, Inc. was contracted by PP&L to identify the root cause of the RHR 2E-217C motor oil cooler failure and to inspect equipment at other locations in the plant cooled by the ESW system.

We worked on-site and in PP&L's Hazleton, Pennsylvania Laboratory and Allentown, Pennsylvania offices from Friday, June 8 through Tuesday, June 12, 1990 inclusive. During this time, we inspected the failed cooler, several other RHR motor oil cooler coils, and other coolers, heat exchangers and accessible piping serviced by the ESW system. We ran on-site microbiological assays at six locations for the presence of sulfate-reducing bacteria (SRB) and acid-producing bacteria (APB) that can cause microbiologically influenced corrosion (MIC), and we took samples of heat exchanger tubes, water and deposits for later analysis.

We worked closely with PP&L's metallurgists and other staff members. We jointly inspected failures, pits, metal surfaces and deposits under the light microscope and scanning electron microscope (SEM) in the'Hazleton Laboratory. We reviewed plant and corporate engineering office records, including technical specifications, procedures, heat exchanger inspection reports, ESW water chemistry and operating conditions, and other related information. PP&L provided access to all records and information pertinent to this project to assist us in our work.

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On June 12, 1990, in the Allentown office, we completed a

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preliminary report of our findings. Subsequently, we carried out the

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following work:

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~ We, carefully inspected sections of RHR lube oil cooler coils and RCIC pump room unit cooler heat exchanger tubes removed during our site visit.

~ We analyzed water and de'posit samples and ran scanning electron microscope (SEM), electron diffraction spectroscopy (EDS) and X-ray diffraction (XRD) analyses on deposits from specific locations, i.e., inside pits, on selected tube specimens.

~ We ran further microbiological studies on selected tubes to assist in characterizing the nature of the corrosion.

~ We studied plant ESW system operating records and other pertinent plant records in detail.

~ We reviewed our own extensive files and carried out a literature review on causes of waterside pitting corrosion of copper and copper alloy heat exchanger tubes.

This Anal report includes all essential information from our June 12, 1990 preliminary report, all new data obtained since June 12, 1990 and our conclusions. Our preliminary report is included in the Appendix and should be considered as part of this complete report.

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N L I N The RHR lube oil coolers and the RCIC pump room unit coolers failed by a combination of microbiologically induced corrosion (MIC) and conventional chemical pitting corrosion mechanisms.

2. The ESW, as measured at the inlet to RCIC lE-228B, is microbiologically very active and contains high levels of sulfate reducing bacteria (SRB) and acid producing bacteria (APB).

3. The ESW A and B loops have been stagnant (not running) between 65 and 75 percent of the time since 1987. During these stagnant periods, deposits formed on the internal (waterside) surfaces of the RHR and RCIC cooler coils and tubes.

Anaerobic conditions under these deposits allowed SRB to generate sulfides that destroyed the protective, passive Qlm on the copper (RHR) coils and attacked the 90:10 cupronickel (RCIC) tubes.

4. MIC did not continue at a high rate under these deposits because of the toxic effects of copper, ions. Instead, conventional under-deposit oxygen concentration cell corrosion became the driving force for continuing pitting attack.

5. SulQdes probably continued to play a role in the corrosion process, even after pit initiation. Continuing presence of SRB in the system allowed sulfides to form away from the corroding copper surfaces. These sulfides then diffused with the water and were able to attack passive films on the metal. Both deep.

sharp-edged pits characteristic of concentration cell corrosion and shallower, rounded pits characteristic of sulQde attack, were found in the RHR lube oil cooling coils (see Photographs).

SEM/EDS element maps show sulfur present in all pits, but at various locations, usually not next to the metal surface.

6. Manganese played a dual role in the corrosion process. In the most severely corroded RHR lube oil cooler coils, e.g., the failed cooler, 2E-217C, no continuous protective deposits were observed. Rather, the deposit appears to have formed as a series of discrete layers, perhaps associated with periods of flow and no flow, water chemistry changes, etc. Cooler RHR 1E-217B showed similar deposits. These deposits contained only small amounts of manganese. Manganese probably acted as an electron transfer agent in these deposits to catalyze the corrosion reactions.

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7. The RHR lube oil coolers in the worst condition (2E-217C and 1E-217B) take water from the ESW B loop and the coolers in the best condition (lE-217A, 2E-217A and lE-217D) are all on the A loop. The reasons for this cannot be positively defined from the available data, but some facts are clear. Prior to June 1989 the ESW A loop ran more frequently and carried more water than the B loop, but at a 20 percent lower flow velocity through the RHR coils. Substantially higher levels of manganese were found in the A loop coils, compared to the B loop. The different flow patterns in the A loop may have allowed more manganese to deposit in these coils and to form continuous films rather than discrete', porous deposits as described in Conclusion 7. The very high levels of manganese found in connecting elbows from coils lE-217A and 2E-217B (one on each loop) remain unexplained.

These elbows were not-corroded in any way.

8. Two RHR lube oil cooler coils, 2E-217B (examined in our laboratories) and lE-217B (examined by Dr. Willertz of PP&L) showed heavier deposits and pitting in the top (water outlet) layers of coils than in the bottom (water inlet) layers. Other coils may also show this effect but were not examined in this way. These observations suggest a temperature effect, but the temperature rise across the RHR lube oil coolers (8'F) does not seem to be sufficient to produce these differences. Also, the RHR pumps only operated between 5 and 10'percent of the time each year, so that very little heat was available from this source.

9. Other than the RHR lube oil coolers, most of the cooling equipment in the ESW system contains 90:10 cupronickel tubes.

The RCIC pump room unit coolers are corroded at least as seriously, as the RHR room coolers. We found one 90 percent through-wall pit in RCIC 1E-228B and one 60 percent through-waQ in 1E-228A. We examined sections from only one tube from each cooler. These tubes showed low manganese levels and heavy, scaly deposits simQar to those found in RHR 2E-217C, the failed RHR lube oil cooler coil. RCIC lE-228B showed the highest level of microbiological contamination of all coolers tested during this study.

10. Copper and 90:10 cupronickel are both highly resistant to corrosion in clean fiowing water, but in biologically active systems 90:10 cupronickel is sometimes more susceptible to biofouling and MIC. During our on-site inspections, we examined several 90:10 cupronickel coolers in the diesel generator system and found little or no pitting. We also examined the 2E-297A GR DX condenser but could not the condition of the metal in these tubes because of 'etermine the large amount of deposit present.

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11. ESW water chemistxy data show a consistent downward trend in conductivity and calcium levels during 1989 and 1990.

Langelier Index values are often above,+0.5 and occasio'nally approach +1.0. Some calcium, presumably as calcium carbonate, was found in most of the RHR and RCIC cooler deposits.

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RE L F IN PE N Lit fIn e Eui mn During our work on-site and in our laboratory, we inspected heat exchanger tubes and/or ESW piping from the following units:

lE-217A RHR lube oQ cooler coil.

2. lE-217B RHR lube oil cooler coil.

1E-217C RHR lube oQ cooler coil.

4, 2E-217A RHR lube oil cooler coil.

5. 2E-217B RHR lube oQ cooler coil.

6. 2E-217C RHR lube oil cooler coil.

7. 2E-217D RHR lube oQ cooler coil.

8. 1E-228A RCIC pump room unit cooler.

9. 1E-228B RCIC pump room unit cooler.

10. 2E-297A ESW GR DX system condenser.

OE-505E1,2D Diesel generator intercooler.

12. OE-507D Diesel generator jacket water cooler.

13. OE-533D Diesel governor cooler.

Ins I n Mtho In doing our on-site inspections, we used the following methods:

~ Visual inspection of tubes and deposits as we saw them in place or as they were presented to us.

~ Videoprobe inspections of tubes in place.

~ Visual inspections with a 15X magnifying lens of the interior surfaces'f cooling coils and tubes that had been split longitudinally.

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~ Microscopic examination .of selected specimens in the PAL Hazleton Laboratory.

~ Microbiological cultures of deposits from coils and tubes, using media specific for sulfate-reducing and acid-producing bacteria (SRB and APB).

In our laboratory, *we did substantial additional inspection and analytical work. These data are summarized in Tables and Figures for easy comparison of specimens:

~ Careful visual observation of the nature of the deposits and corrosion on each specimen, with photographic documentation (Tables 1 and 12 and Photographs 1 through 41).

Physical measurements, i.e., size, wall thickness, etc.

2). 'Table

~ Deposit weight density measurements (Tables 3 and 12).

~ Pit depth measurements (Tables 4 and 12).

~ Water chemistry studies (Table 9 and Figures 4, 5 and 6).

~ Chemical analyses of deposits (Tables 5 and 6 and Figure 2).

X-ray diffraction analyses to identify compounds in deposits (Table 7).

Microbiological analyses of sample cultures on-site (Table 8 and Figure 3).

SEM/EDS analyses to identify elements in deposits (Table 6, Figures 9 through 22 and Photographs 42 through 49).

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Thomo,s M. Laronge, Inc.

Please refer to these Tables and Figures in connection with the following discussion. The photographs are arranged in a general order of increasing magniQcation, so that by perusing the photographs, the reader can gain an increasingly detailed comparison of the nature of the pitting on the various specimens mcaznined.

Phsi M urmn rv tion Figure 1 is a schematic diagram of an RHR pump motor, showing the arrangement of the lube oil cooling coQs. The coils are arranged in a stack of six layers, with four turns in each layer. For identiQcation purposes we have numbered the coils from top to bottom and lettered the turns from the inside out, as shown in Figure 1. Thus, coil 3B is the second from the inside turn in the third layer from the top.

Physical measurements are shown in Table 2. 'ur measurements show that the RHR lube oil cooling coils and the RCIC room cooler tubes are generally within specifications. Deviations are small and can be attributed to problems in wall measurements on tubes containing deposits and to some deformation that must occur when copper tubing is formed to make the RHR coils. There is no evidence whatsoever from these measurements that any appreciable thinning of tube walls due to general corrosion has occurred.

The RHR lube oil cooling coils are reportedly made from type K copper, and the RCIC room cooler tubes from 90:10 cupronickel. No wet chemistry tests were done to verify these compositions, but EDS analysis on a galled edge of one tube from RCIC 1E-228A confirmed 90:10 cupronickel in this tube.

A. RHR Lub Oil ler

1. RHR lE-217A We inspected sections cut from coils 2 and 5 in this cooler on-site (see Figure 1). These sections were similar. Both contained a Page 8

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light, smooth layer of black deposit. Very slight, irregular pitting was 1 observed under this'deposit. There was no visible tuberculation. We judge this coil to be among the least corroded (pitted) of all the RHR coQs that we studied.

We also examined several 90 degree elbows that connected the layers in the lE-217A coil. These elbows appear to be made from a different alloy than the copper coil, perhaps a brass. These elbows contained a substantial amount of a black, powdery deposit. Some bare metal was visible. We measured the deposit weight density at 15.4 mg/ft2. No visible corrosion could be seen in these elbows. However, pitting was clearly visible in the copper tube connected to one elbow (Photographs 37, 38 and 39).

2. RHR lE-217B

'We did not inspect this coil on-site. In our laboratory, we inspected layer 3B. (see Figure 1) from this coil. We found a large amount of deposit mixed with tubercles ranging up to 0.25 inch in both diameter and'height (see description in Table 1). The deposit weight density, measured at 31.7 gm/ft2, was second only to the density measured in RHR 2E-217C (see Table 3). Pit density was lower than found in the 1C and 2C RHR lube oil coolers, but substantially higher than in the lA and 2A coolers (Table 4). The maximum pit depth measured on our specimen was 0.025 inch, or 35 percent wall penetration (Table 4). This compares with 0.042 inch measured by Dr. Willertz of PP&L on a different section from the same coil. The nature and depth of pitting in the RHR lE-217B coil can be seen in Photographs 20 through 23.

3. R~RR 13-217 This cooler was not inspected on-site. In the laboratory, this specimen was. found to have the highest measured density of pitting, but not the highest pit depth or wall penetration (Table 4). The deposit weight density, at 24.1 gm/ft2, was in the highest group Page 9

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measured (Table 3). Deposits were smooth and brown to black in

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color, with many bright green, red and silver colored crystals around

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and inside pits. Pits, mostly covered by tubercles, were large, shallow

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and hemispherical. 'Ihe deposits and pitting in this specimen can be seen in Photographs 28 through 31; the crystals are apparent in SEM Photograph 47.

4. RHR 1E-217D For the record, we note here that no specimens from RHR lE-217D were provided for our inspection. Dr. Willertz reported only light deposits and tuberculation, and very little pit penetration in this'ube.

5. RHR 2E-217A This coil was not inspected on-site. In the laboratory, this tube section was like 1E-217A. The brown deposit was similar to that in lE-217B, but much smaller in quantity (Table 3). Tubercles were minor and there was no visible pitting or general corrosion.

6. RHR 2E-217B On-site we found this coil to be intermediate in condition between 1E-217A and 2E-217C. The specimen we examined contained stringy black deposits that covered part, but not all of the surface. No signiQcant tuberculation was present, but pit depths were quite severe.

Laboratory inspections confirmed these observations. We were able to examine specimens from the second coil from the top (2E-217B-2) and the second coil from the bottom (2E-217B-5), as shown in Figure 1 and Table 1. The entire 2E-217B-2 coil was sent to our laboratory. Photograph 10 shows this coil as split for inspection. The center tube was mcamined in detail.

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Thomas M. Loronge, Inc.

The differences in deposit weight density, pitting density and pit penetration between 2E-217B-2 and 2E-217B-5 (Tables 3 and 4) confirm similar observations made by Dr. Willertz on the 1E-2178 coQ, using X-ray examination. Deposit characteristics, tuberculation and pitting in the upper coil (2E-217B-2) were much like the failed coil 2E-217C. (see below) except that pits in 2B were mostly hemispherical. Deposition and pitting in 2E-217B-5 were very light; this section appeared, visually, much like lE-217A and 2E-217A.

Photographs 32, 33 and 34 show the nature of the pitting in 2E-217B.

Unfortunately, these photographs do not distinguish between the 2B-2 and the 2B-5 coils.

We examined four 90 degree bends from 2E-217B. These bends appeared, visually, to be made from copper and seemed to be quite different from the bends in the 1E-217A coil (see above). Deposit weight densities were in the intermediate range and no pitting or general corrosion was observed. See also the discussion of chemical analyses of deposits, (Page 19.and Table 5, Page 50).

7. ~2E-217 It was a through-wall failure in this coil that alerted the plant to the pitting corrosion problem in the RHR lube oil coolers. and other heat exchangers served by the ESW system. On-site, we found the interior surface of the 2E-217C coil covered with a thick, dense, layered scaly deposit, quite different in appearance from the other coils. However, the tube we saw had been removed from the system several days before our visit, so that the deposits were quite dry whQe other tubes were wet.

On-site, we found large tubercles covering numerous random pits over most of the surface. These pits varied greatly in size, shape and depth. Both hemispherical and irregularly-shaped pits were observed, as opposed to the mostly hemispherical pits found in other 1 coils. Some of the pits in 2E-217C were sharp-edged and quite deep.

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Laboratory inspections conflrmed the severity of corrosion and deposition in this coil. The deposit weight density was the highest measured in any coil tTable 3) and pit density and depth were also among the highest measured (Table 4). Photographs 17, 18 and 19 show the heavy deposits and deep pits found in this coil. A near through-wall pit can be clearly seen in the lower sawed edge of the tube in Photograph 17.

8. 2E-217D This coil was not exanQned on-site. In the laboratory, we found the deposit weight density to be high at 27;3 gm/ft2, comparable to deposits in coils lE-217B and 1E-217C. Pit density was less severe than in either of these tubes. Pit penetration in 2E-217D was similar to 1E-217C and less serious than in 1E-217B. The deposits were typically brown to black with green edges around small tubercles. Pits were small and hemispherical. Photographs 24 through 27 compared to Photographs 17, 18 and 19 show the differences between the deposits found in 2E-217D and 2E-217C.

R R I Pum R m ni I r 1E-22 A n lE-22 B The RCIC coolers are reportedly tubed with,90:10 cupronickel tubes, as explained above. The tubes are straight and installed horizontally in the coolers. The nominal tube diameter is 0.5 inch (Table 2). This means that the RCIC tubes may be more subject to loss of flow due to partial tube blockage than the RHR lube oil coolers if deposits should form in these tubes.

The RCIC lE-228A cooler was opened in our presence during our inspection visit so that we were able to examine the internal deposits immediately upon exposure to air. This is important because anaerobic bacteria that can be responsible for microbiologically influenced corrosion (MIC) tend-to become inactive upon exposure to oxygen.

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The tubes in RCIC lE-228A contained loose, brown deposits.

Most of these deposits seemed to be in the form of well Qocculated solids with clear water. The tube metal appeared to be relatively clean during our on-site inspection. We understand that the RCIC IE-228A cooler is served by the ESW A loop. PP&L informed us that the RCIC pump room unit coolers were cle'aned about three years ago and that large amounts of black deposit, presumably manganese, were removed at that time.

The 1E-228B cooler had been opened and cleaned for several days before our inspection. One tube had not been cleaned, and we found this pipe to contain a large amount of loose, black deposit. We understand that the lE-228B cooler is served by the ESW B loop.

t One tube from each of the RCIC coolers was sent to our laboratory for inspection. Visually, the tube from RCIC lE-228A contained less deposit and far fewer pits than the IE-228B tube.

When measured, however, deposit weight densities in these tubes weve roughly the same (Table 3) and pit density seemed to be. higher in 1E-228A than in lE-228B (Table 4). The A cooler showed the deepest single pit measured during this entire study; 0.05 inch, corresponding to 91 percent wall penetration. The lE-228B cooler showed a maximum of 0.036 inch pit depth with 60 percent wall penetration. These differences may not be signiQcant, since only one small portion of one tube from each unit was examined. Also, the vertical and horizontal splits described in Tables 3 and 4 are questionable because tube orientation could not be maintained precisely during removal from the unit and during cutting.

Photographs 14, 15 and 16 show the nature and density of

, deposits and pitting in 1E-228A, and Photographs 40 and 41 show a close-up view of one pit from this tube. The typical green, red and brown deposits found in both Dxe RHR and RCIC coolers can be clearly seen in these photographs.

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G ESW Su 1 Lin R I lE-22 B During our on-site inspections, we were able to examine the ESW B supply line to RCIC lE-228B. We understand that this is mild steel piping. This line was heavily corroded and covered with a uniform layer of brown scale ranging up to 3/16 inch in thickness. No tubercles were seen and no pitting could be found under the deposit, as far as we could reach into this line. See below for a discussion of microbiological testing in this pipe.

This pipe, as we saw it, was typical of mild steel pipe exposed to corrosive water for many years with no chemical treatment. The heavy layers of corrosion-produced scale are probably, at this point, providing some corrosion protection to the pipe. We believe that the condition of this pipe is similar to that of most of the ESW piping exposed to similar flow conditions.

D. th r In i n During our site visit, we inspected several coolers and condensers that could not be dismantled for subsequent laboratory examination. These inspections are described in detail in our preliminary report (Appendix);, the information is summarized briefly below.

l. OE- 7D Di I n r tor ack W r pier Tubes in this cooler were reported to be 90:10 cupronickel.

Previous eddy current (ET) testing of this cooler had identified one tube with at least 60 percent wall penetration. We inspected this tube in place, using fiberscope equipment, and found many pits that appeared, through the fiberscope, to be very deep. The pits were randomly distributed and irregular in shape. The cooler had been cleaned before we arrived so that we did not see the deposits in place.

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2. E- D Di 1 v rn r I r We examined this small 90:10 cupronickel single tube cooler after cleaning. Only minor pitting could be seen in this tube.

3. OE-505E1 2D Dies 1 n r or Int r poler The tubes in this 90:10 cupronickel cooler were too small to permit entrance of the fiberscope. The tube ends were clean and contained many small pits. No other observations could be made.

4. 2E-2 7A W R DX m n n r ~

This exchanger was opened just before our inspection. The tubes and tube sheets were covered with heavy deposits that made viewing the tubes impossible. The deposits seemed to include corrosion products, scale and loose, slimy material. Microbiological activity in this deposit was low (Table 8, Page 54).

e 'i Discussion of Measurements and Ins ections Table 12 summarizes the inspection information from Table 1 through 4 and groups the coolers by ESW loop. Based on these data we rank the RHR lube oil coolers in the following way, from worst to best:

Pit Density Deepest Pit Deposit Wt. Density

~pi ~ink Ini he~ gm~~f Worst 1C 25-300 2C 0.028 2C 37.90 2C 1-200 1B 0.025 1B 31.73 1B 5-50 2B-2 0.025 2D 27.25 2B-2 4-50 2D 0.015 1C 24.07 2D 5 1C 0.013 2B-2 13.21 2B-5 1 2B-5 0.007 2B-5 6.88 t

2A NM 2A NM 2A 525 1D NM 1D NM 1D NM Best lA NM lA NM 1A NM NM = Not Measured.

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The precision of the data shown above is probably statistically unjustiQed, since only one section of tube from each coil was examined for each data point. Nevertheless, some trends are apparent.

First, RHR lube oil coolers on the ESW B loop seem to be in worse condition than those on the A loop. With the possible exception of RHR 2E-217D, all of the RHR B and" C coolers, using ESW B water, show substantially higher pit densities and depths and higher deposit weight densities than the RHR A and D coolers on the ESW A loop.

In spite of the relatively high place of RHR 2E-217D in this ranking, pit densities and pit depths for this cooler are more like the A lo'op coolers than the B loop. Only the deposit weight density for RHR 2E-217D seems to be inordinately high. However, it is interesting that Dr. Willertz's ranking of the RHR coolers is almost exactly the same as our ranking based on deposit weight density.

The fact that both deposition and pitting were more severe in the top halves of RHR lube oil cooling coils 1E-217B (from Dr.

Willertz's report) and 2E-217B, compared to the bottom halves, suggests that temperature may be a signiQcant factor in this problem.

However, the temperature rise across the RHR lube oil coolers is reported to be only 8'F. Also, the RHR pumps have operated less than 10 percent of the time since 1987, so that heat generated by these pumps does not seem to be si~ificant. See the section of this report dealing with ESW system operations beginning on Page 27 for further discussion of this subject.

The physical condition of the RCIC pump room unit coolers does not seem to be a function of the ESW loops. When inspected on-site, lE-228B seemed to be more heavily fouled than lE-228A, but measured deposit weight densities are about the same. Both tubes are heavQy pitted.

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ANALY E F DEP I AND AL RFA E An i M h A variety of instrumental and wet chemical analytical methods was used to assist in identifying elements and chemical compounds present in the deposits in the RHR lube oQ coolers, the RCIC pump room unit coolers and the ESW GR DX condenser 2E-297A. These methods included:

Inductively coupled argon plasma spectroscopy (ICAP) combined with thermal and wet chemical methods to

., deflne the overall elemental composition of the deposits.

Scanning electron microscopy (SEM) and electron diffraction spectroscopy (EDS) to identify elements present in microlayers in and around speciQc pit locations.

X-ray diffraction (XRD) to define specific chemical compounds present in selected pits.

On-site microbiological culture tests to detect sulfate reducing bacteria (SRB) and acid producing bacterial (APB) that can cause microbiologically influenced corrosion (MIC).

Direct examination of cleaned metal surfaces to help identify morphological features characteristic of MIC and general under-deposit pitting corrosion.

All of this work is presented and discussed in this section of the report.

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hmi l Table 5 presents the results of ICAP, thermal and wet chemical

.analyses of deposits. The green and some of the red deposits reported in Table 1 and shown in the photographs correspond to copper compounds, probably corrosion products. This is confirmed by the high levels of copper found in all the RHR and RCIC deposits. It is entirely possible, however, that these high copper values also include copper metal scraped from the tubes during the sample collection process.

The two analyses reported for RHR 2E-217C represent different samples run by separate laboratories. Agreement is excellent except for copper, discussed above, and sodium, a very common contaminant.

t The RHR lube oil cooler data from Table 5 are plotted in Figure

2. This Figure compares coolers 1B and 2C (heaviest deposits and deepest pits), cooler 1C (high pit density but intermediate pit depth and deposit weight density) and cooler 1A (least deposits and pit:ting of all coolers examined). The differences among these analyses are striking:

~ Coolers 1B and 2C, in the worst condition, show low levels of iron, manganese and calcium, and relatively high levels of sulfur.

~ Cooler 1C shows high iron and manganese, slightly higher calcium and roughly half the sulfur of coolers 1B and 2C.

~ Cooler lA, in the best overall condition, shows very low sulfur, the highest manganese and an intermediate iron level.

t Based upon experience with the combustion and thermal decomposition method used to determine total sulfur in the deposit samples, our laboratory estimated that most of the sulfur in the Page 18

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deposits from RHR lE-217A and 2E-217C was probably present as sulfate. This is, of course, not a quantitative determination, but we

~ ~

reported sulfate in Table 5 on that basis for discussion.

Since many inorganic sulfates are soluble it might seem unreasonable to expect sulfates in deposits of this type. In fact, however, sulfates are commonly found in water-formed deposits, e.g.,

in recirculating cooling water systems. Even though simple sulfate salts often have appreciable solubility, complex inorganic and organic sulfates exist that are less soluble. Also, the sulfate ion, because of its high charge density, adsorbs easily on many substrates along with appropriate cations for charge balance..Finally, most flocculant hydroxides, including hydroxides of iron, aluminum, copper, nickel and manganese among others, wQI readily occlude sulfate salts as they precipitate. Many corrosion products precipitate first as the hydroxide and then dehydrate and crystallize to form oxides and other insoluble complex compounds. Substantial amounts of sulfate can be held on a metal surface in this way.

No firm conclusions can be drawn from these ICAP data alone, but the obvious trends must be recognized. It is well known that manganese can act as a corrodant or a catalyst for corrosion, or, under different circumstances, as a film-forming inhibitor. Iron, particularly iron transported to the corrosion site in the water rather than formed in place as a corrosion product. can also provide protection. Sulfur is commonly found at enhanced levels in deposits formed by MIC. See the Root Cause Failure Analysis section of this report for background information and references on the behavior of manganese, iron and sulfur in corrosion processes.

Curiously, the deposits in the RHR lE-217A and 2E-217B elbows are almost identical to each other and very diQ'erent from the other RHR cooler deposits. The elbows contain much less copper, more iron, very high levels of, manganese and a significant amount of zinc compared to the RHR lube oil cooler tubes themselves. These

.data indicate that the elbows from both. coils. may, in fact, be made Page 19

Thornos M. Lo,ronge, Inc.

from some form of brass (see the inspection discussions above). The high manganese levels in the elbow deposits confirm the black deposits found during inspection, but there is no ready explanation for the presence of higher manganese in the elbows than in the coils.

The analysis of the RCIC pump room unit cooler 1E-228B deposit (Table 5) is different from the RHR lube oil cooler deposits.

This cupronickel tube showed one of the deepest pits measured during this study (Table 4) and the analysis shows the expected copper and low level of nickel in the deposit. The iron level is moderate compared to the RHR cooler deposits and the manganese level is very low. This seems to parallel the deep pitting and low

<manganese deposit content observed in RHR 1E-217B and 2E-217C.

However, in 'contrast to the RHR coolers, the sulfur content in the RCIC lE-228B deposit is very low.

Finally, the deposit in the DX 2E-297-A condenser is entirely different from the deposit in the RHR and RCIC cooler coils. This is a much more'typical waterside corrosion and fouling deposit, high in iron and silica, very low in manganese, copper and sulfur, and with a significant loss on ignition indicating the possible presence of organic material. We were informed that our inspection represented the first

. time the 2E-297A heat exchanger had been opened, so the

'a'ccumulation of water-borne solids is not surprising. This exchanger must be cleaned to restore performance, and at that time it will be important to inspect the tubes for possible corrosion damage.

SEM-EDS An I f De EDS spectra of selected pits from the RHR lube oil cooler coils and RCIC pump room unit cooler tubes are presented in Figures 9 through 22, along with the respective elemental compositions ~

calculated from stand ardless analysis (in which the data are interpreted mathematically without the use of physical standards).

'he corresponding SEM photographs appear as Numbers 42 through-

49. Element maps for sulfur, chlorine, iron and manganese are shown Page 20

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as Figures 23 through 29. All of these data are summarized for e discussion in Table 6.

EDS spectra were taken at two selected microlocations in each deposit. For wimple, referring to Table 6, Photograph 42 shows a speciQc pit in RHR lube oil cooler 1E-217B-3B. Figure 9 shows the EDS spectrum taken in the middle of the deposit in this pit and Figure 10 shows the spectrum of the deposit at the base of the pit, next to the metal. The corresponding element map for this pit appears as Figure 23.

Considering the heterogeneous nature of the deposits and the specificity of the EDS spectra, the agreement between the EDS data and the ICAP results in Table 5 is quite good. The EDS analyses for chlorine (chloride) and sulfur are particularly interesting because these elements are often found near active corrosion sites. Chlorides accumulate in under-deposit pitting corrosion cells by ion transport mechanisms, while sulfur often appears at MIC locations through microbial metabolism.

The chloride and sulfur data in Table 6 do not show any consistent pattern. Consider, for example, the EDS spectra from three diferent pits in RHR lube oQ cooler coil lE-217B-3B as listed in Table 6.

~Fi ure Location ~Chlorid Sulf'ur RHR lE-217B-3B 9, 10 Inside pit 16.42 None Pit base 6.75 None 11,12 Inside pit None 6. 12 Pit base None 13.35 13,14 Inside pit 15.93 3.57 Pit base 0.24 None These differences may. represent heterogeneous deposits or they may be additional evidence that more than one corrosion mechanism Page 21

t Thomo,s M. Laronge, Inc.

may be involved in the pitting attack in the RHR and RCIC coolers. Dr.

Willertz ran similar SEM/EDS analyses on the RHR coils and found the same variations, both on pits from the same coil and among different coils. Agreement between the two sets of analyses seems to be good with the possible exception that Dr. Willertz's data show more elements and especially more sulfur in some cases than do our results.

In an effort to identify specific chemical compounds in the deposits, we ran X-ray diffraction studies on selected deposits from RHR lube oil coolers lE-217B-3B, RHR 2E-217C and a 90 degree bend from RHR 2E-2178. The results are shown in Table 7. The data are disappointing. Only the expected cupric hydroxide. cuprous oxide (cuprite) and magnetite were identified. X-ray diffraction is sensitive only to compounds present in amounts greater than about 2 percent of the total, but we had hoped that other crystalline compounds, particularly sulfur compounds, could be identiQed in this way.

Element maps (Figures 23 through 29) are a useful way to identify the locations and distribution of particular elements in a matrix. Element mapping does not determine concentrations of elements.

Figures 23 through 29 show that all four mapped elements, sulfur, chlorine, manganese and iron are present in all deposits.

However, the maps do not reveal any consistent patterns in element distributions in the deposits. On the other hand, the maps are especially interesting because they seem to confirm the differences shown by the ICAP and SEM/EDS analyses.

For acample, Figures 23, 24 and 25 are elemental maps of three pits in RHR lE-217B-3B. Figure 23 shows a binodal void in the middle of the pit, with almost none of the four mapped elements present in this area. Figure 24 shows both sulfur and chlorine

'oncentrated in the middle of the pit, with manganese and iron in an outer ring. Figure 25 shows manganese, iron and some chlorine in the middle of the pit, with sulfur around the outside.

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Micr i lo i al An 1 Table 8 summarizes all of the microbiological analyses coQected during this investigation. On-site culture tests for live sulfate reducing bacteria (SRB) and acid-producing bacteria (APB) are shown in the right two columns of this Table. These bacteria are commonly involved in microbiologically influenced corrosion (MIC). Laboratory microscopic counts for total bacteria (all types) and for total SRB are shown in the left two columns.

To put the data in Table 8 into perspective, consider the following guidelines that are commonly applied to both once-through and open recirculating cooling water system. With a total bacterial count below 10~ to 103 cells per ml or per gram, a system is considered to be under good microbiological control. At this total count level, anaerobic bacteria should always be less than 10~ per ml.

Between 103 and 104 total cells per ml, a cooling water system is considered to be biologically active. Above 104 to 10~ cells per ml there is cause for concern about biological fouling and corrosion problems and above 106 cells per ml, immediate action is usually considered necessary to prevent damage to the system.

On this basis, the 8.5 x 109 cells per ml total count measured in the ESW B supply water to RCIC lE-228B (line 1 in Table 8) is extraordinarily high. Total microscopic counts include both live and dead bacteria, but even if as few as 10 percent of these bacteria were alive in the system, the counts would be well above the danger point.

It is also very unusual to find total SRB levels, alive and dead, above 106 per ml in a water sample. The on-site culture tests for live SRB and APB in this water sample agree well with the total microscopic SRB count and indicate that as expected, most of the anaerobic bacteria t

died or became inactive during shipment to the laboratory.

It is clear that the ESW B supply water is highly contaminated with both aerobic and anaerobic bacteria. We have no water analyses Page 23

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from the ESW A system, but since these systems circulate from a common source, we can assume that ESW A is also contaminated.

This is not surprising, since the spray pond receives only occasional algaecide treatment as needed; no regular chlorination or microbial control program is used.

The deposit sample taken from the RCIC lE-2288 pump room unit cooler (line 2 in Table 8) produced the highest on-site live bacterial deposit counts found during this study, greater than 107 cells per gram of deposit. This cooler had been open for several days before our inspection. The fact that high viable SRB and APB counts were observed even after this exposure to air indicates that activity must have been very high when the system was closed.

t On-site test results from the three RHR lube oQ coolers and the DX condenser are all one to three orders of magnitude lower than the 1E-228B RCIC room cooler. Note, however, that live SRB and APB counts from RHR lE-217A, the RHR cooler in the best condition, are one to two orders of magnitude ~hf h r than from 2E-217C, the failed cooler in the worst condition. This difference may not be really signiQcant because the sample from 2E-217C was taken after the coil had been dry and exposed to air for several days, while the other RHR lube oil cooler samples were taken while the coils were still wet.

However, the total microscopic counts show the same trend. As explained above, total microscopic staining techniques as used in this work count both live and dead bacteria and thus provide an indication .

of what the populations might have been like while the system was on line. These data are presented graphically in Figure 3. The numbers do not exactly parallel the culture results, but this is to be expected since variable numbers of anaerobic bacteria will die depending upon conditions to which they are exposed.

The total count data for the four deposit samples shown in --*. "

Figure 3 are approximately the same, within the precision of this test.

However, the SRB levels in the deposits from RHR 2E-217C and RCIC Page 24

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1E-228B, a sever'ely corroded cupronickel cooler, are both two orders of magnitude lower than lE-217A. This is a signiQcant'difference and it indicates that microbiological activity alone cannot explain the differences in pitting and deposit formation found among both the RHR lube oQ coolers and the RCIC pump room unit coolers.

Sections of coils from RHR lube oil coolers 1E-217B and 2E-217C were carefully examined under a stereomicroscope for direct evidence of MIC on these copper tubes. Indications of MIC are clearly present, but no pits could be found in these tubes that could be entirely and unequivocally attributed to MIC.

Di i n fAn R 1 Manganese, and probably also deposited iron, appear to be providing'corrosion protection in the RHR lube oil coolers rather than increasing corrosion. Sulfur levels, as determined by ICAP analysis, correlate with observed depth of pitting, but location specific SEM/EDS analyses for sulfur and chloride do not correlate as well.

Element maps show both elements, along with manganese and iron, present in all deposits, but in some cases next to the metal surface and in other cases in the deposit itself or even outside the pit.

Microbiological counts, usually associated with the presence of sulfur compounds in corrosion product deposits, do not correlate well with either sulfur levels or observed frequency and depth of pitting in the RHR lube oil coolers, although all deposits tested showed high levels of anaerobic and total microbiological activity.

All of these data, along with the observed differences in pit morphology, frequency and depth, indicate that two different mechanisms are controlling the pitting corrosion process in the RHR lube oil coolers and the RCIC pump room unit coolers. These mechanisms. are. conventional under-deposit pitting attack and MIC. It is probable that many pits were microbiologically initiated, but then advanced by conventional mechanisms.

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MIC and conventional under-deposit corrosion and sometime be distinguished by differences in the morphology (shape and size) of the pits. Using mild steel as an example for discussion, MIC tends to produce circular, dish-shaped pits with rounded edges anQ often with smaller pits within the main pit. Conventional under-deposit corrosion usually produces pits with irregular shapes, sharp edges and straight or undercut sides.

On copper, these differences are obscured by the fact that the bacteria responsible for MIC often die or become inactive due to the toxic effects of the copper ions generated by corrosion. The deposits remain, however, and corrosion continues by conventional mechanisms so that the pit morphology becomes obscured. See the Root Cause Failure Analysis section of this report, beginning on Page.

35, for further discussion of this subject.

The following section of this report discusses ESW water chemistry and ESW and RHR pump operations. This information is needed to help explain why this corrosion is occurring and why deposit compositions and rates of deposition and pitting attack are different among the different RHR and RCIC coolers.

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E W SY TEM HEMI TRY AND PERATIQN

~ESW h Available ESW chemistry parameters for 1989 and 1990 are plotted in Figures 4 and 5. Conductivity and calcium levels (Figure 4) show a clear downward trend during this one and one-half year period.

Turbidity fluctuated widely during this period, while the pH remained in the 8 to 9 range (Figure 5). No explanation for these trends is readily available.

Figure 6 shows temperature and Langelier Stability Index (LSI) calculations for the ESW, as provided by PAL. It is clear from Figure 6 that the LSI will often be above +0.5, and occasionally above +1.0, creating a definite possibility for calcium carbonate scale formation.

Under borderline scaling conditions, such as these, small temperature e or concentration changes in the water can create the driving force needed to cause calcium carbonate to precipitate in a heat exchanger.

Table 9 presents an analysis of the ESW B water supply to RCIC pump room unit cooler lE-228B, taken during our site visit on June 9, 1990. LSI values for this sample, as shown in Table 9, range from +0.4 at 80'F to +0.7 at 110'F, making this sample marginally non-scaling.

The analysis in Table 9 shows the ESW as analyzed to be a generally good quality water. Parameters of particular interest are iron at 0.74 ppm, manganese at 0.75 ppm and sulfate at 53.6 ppm. These levels of iron and manganese are more than sufficient to account for the deposits of these elements found in the RHR lube oil coolers and the RCIC pump room unit coolers. With roughly 54 ppm sulfate present in the water, it is reasonable to expect some sulfate compounds to be adsorbed or occluded in corrosion product deposits.

t This provides a food source for active SRB and indicates that at least some of the sulfur reported in the RHR and RCIC cooler deposits may he present as sulfate (see Table 5).

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Recommendations for water treatment at the Susquehanna plant are beyond the scope of this report. The data clearly indicate that the ESW is at least occasionally scaling in nature, and the microbiological data discussed in a previous section show that the system is highly contaminated with bacteria.

E W n RHRPum r n The nature of the flow patterns through the RHR lube oil coolers and the RCIC pump room unit coolers can have a major impact upon deposit formation and subsequent corrosion in these units. To investigate this problem, we studied the operation of the ESW system pumps and the RHR pumps in some detail.

We appreciate the cooperation offered by PP&L personnel in obtaining the operating data necessary for this study. Not aQ the data-were readQy available, and the first information provided to us turned out to be incorrect. We have reviewed this problem several times, and the following discussion is based upon the latest information which PP&L assures us is reliable.

tm r in Our study is based upon the following PP&L information:

The ESW is circulated from a large spray pond through various equipment and back to the pond. Makeup water to the ponds, mostly from the main condenser cooling tower blowdown, with additional makeup from the Susquehanna River as needed.

The ESW system is divided into two loops, labeQed A and B. Two pumps, labeQed ESW A and C, drive water through the A loop and pumps B and D drive the B loop. These pumps take water from a common suction point in the Page 28

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spray pond. Water returns to the pond through two separate headers.

~ The following coolers that we have examined are connected in parallel across the ESW A loop:

RHR lube oil coolers 1E-217A and D, and 2E-217A and D.

RCIC pump room unit cooler lE-228A.

ESW GR DX system condenser 2E-297A.

~ The following coolers that we have examined are connected in. parallel across the ESW B loop:

RHR lube oil coolers lE-217B and C, and 2E-217B 0 and C.

RCIC pump room unit cooler lE-228B.

~ At any time the ESW is flowing, one or both of the ESW A and B loops may be running and either or both of the ESW pumps on the active loop(s) may be in use. Water circulates through all of the equipment. on each loop whenever that loop is running.

B Th EWSr Pn The volume. of water in the spray pond is estimated by PAL at 26 million gallons. We understand that makeup'from the cooling tower blowdown" runs at from 300 to 1000 gpm, with an additional 200 gpm available from the river as needed.

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We did not personally inspect the spray pond. We understand from PP&L personnel and from water treatment vendor reports that the pond water quality varies seasonally in turbidity and dissolved and suspended solids. During the summer months, algae grows in the pond; this is controlled by occasional treatment with algaecide and chlorine around the edges and across the surface of the pond. It is clear that the spray pond is a source of microbiological contamination and possibly also suspended solids in the ESW water and coolers.

Chlorine has, in the past, been added to the ESW pump suction point, but this has not been done in recent months.

C E W RHR m Run Tim PP&L provided monthly run time data in hours from August 1986 through May 1990 for both the ESW and the RHR pumps. These data are recorded for discussion in Table 10. In calculating the "Assumed Total" run times shown in Table 10, we used the following guidelines:

~ We understand that prior to June 1989, the entire cooling load for the diesel generators was carried by ESW loop A and for that reason, both pumps, ESW-A and ESW-C, ran whenever the A loop was in operation. To arrive at a total run for the A loop during this period, we simply used the higher of the two hourly numbers each month for pumps ESW-A and ESW-C.

During this same time period, the load on the ESW B loop was lighter and usually only one pump was in operation.

To calculate the total monthly run hours for the B loop, we therefore used the sum of the recorded hours for the ESW-B and ESW-D pumps.

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From June 1989 forward, the piping was rearranged so that the diesel generator cooling load was shared between the ESW-A and B loops. During this period, it has been normal practice to operate only one pump at a time in each loop. We, therefore summed the data for each month, as above, to calculate assumed total run hours for each loop.

The assumed total monthly run times show a good deal of scatter that obscures any significant trends. To smooth the data, we calculated annual run time hours as a percent of the available hours (8,760 hours0.0088 days <br />0.211 hours <br />0.00126 weeks <br />2.8918e-4 months <br /> in a year). These data are shown in Figures 7A and 7B, representing the ESW-A and B loops, respectively. These Figures also include the percent run times for the RHR pumps from Table 10, t simply calculated by summing the monthly data.

The higher run times shown for both ESW loops in 1989 compared to other years may be a calculation error resulting &om the fact that both pumps probably did run together on each loop part of the time after June 1989. This question does not significantly affect the data for our purposes.

It can be seen from Figures 7A and 7B that the ESW A loop ran for roughly 35 percent of the time from 1987 through May 1990 and the ESW B loop ran for about 25 percent of the time, on the average.

The exact Qgures are not important. Conversely, the data say.that the A loop was stagnant for 65 percent of the time and the B loop for 75 percent 'of the time. It follows that the coolers connected to each loop, as listed under System Operations above, were also stagnant for these periods of time. We assume that the coolers were not allowed to drain and remained full while stagnant.

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The existence of long periods of stagnation in the ESW water system is an important factor in understanding the pitting failures that occurred in the copper RHR lube oil cooling coils and the 90:10 cupronickel RCIC pump room unit coolers. The presence of stagnant, contaminated water in these coolers for extended time periods represents the worst possible condition for corrosion protection of copper and copper alloys, particularly with no specific corrosion inhibitors for copper in the water. This problem is discussed in detail in the following Root Cause Failure Analysis section of this report.

The RHR pump percent run time data in Figures 7A and 7B are a measure of the time that heat was applied to the RHR lube oil cooling

. coils. We have no information on the times that heat was applied in the RCIC pump room unit coolers.

Heat was applied to the RHR lube oil coolers for a small fraction of the total time, but again, more in loop A than in loop B (see Figures 7A and 7B). Given the 8'F temperature rise across these coolers, as discussed above, and the short RHR pump run times, it seems unlikely that temperature differences across the cooler coils could be a significant factor in the deposition and corrosion process.

Nevertheless, the data show that the RHR pumps with the "best" lube oil coolers, namely lA, 2A and 1D, ran perhaps twice as much as those pumps with the "worst" coils, namely 1B, 1C and 2C.

D. RHR Lu il lin W r Fl w V loci Flow velocity is an important factor affecting the nature and degree of both deposition and corrosion that can occur in tubular equipment. The initial data supplied by PAL showed very high flow velocities in the RHR lube oil coolers. This seemed inconsistent in view of the loose deposits found in some coolers and the fact that no erosion or erosion/corrosion was found in any of the cooler tubes or elbows that we examined. This,was confirmed by Dr. Willertz's inspections of these tubes.

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PAL cooperated fully with us in resolving this. issue and was able to supply new flow velocity data that seem to be reasonable and that PPM. assures us are their best estimates. These data are shown in Table 11 and Figures SA and SB, for the A and B loops respectively.

PP&L provided velocity data for the A loop for all three time periods shown in Table ll and for the B loop for the period from June 1989 through June 1990. B loop data were not available for June 1986 through June 1989. At PP@L's suggestion, we calculated flow velocities for the B loop during this period at 20 percent above the corresponding A loop velocities.

The lower flow velocities in the A loop from June 1989 through 1990 may correspond to more frequent use of one pump rather than two during this period (see above). There is no simple explanation for the higher flow velocities in the B loop, especially during the June 1989 to 1990 period for which hard data are avaQable. These higher velocities go along with shorter operating periods for the B loop, as explained in the previous discussion.

Typical critical water velocities, above which erosion and erosion/corrosion damage can be expected in heat exchanger tubing, have been reported in the literature:

Materi 1 ri 1W rV1 i R fr n Copper alloy ¹122 6 fps Admiralty Brass alloy ¹44300 10 to ll fps 90:10 Cupronickel 12 to 15 fps alloy ¹70600 The velocities in Table 11 and Figures SA and SB are above the guidelines for copper as quoted above. Velocities in the 0.5 inch diameter RCIC pump room unit coolers are lower than in the RHR tube'ofl coolers at about 2 to 3'feet per second. Except for some minor directional nature in the deposits in one RHR lube oil cooler Page 33

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(RHR lE-217B, see Table 1), we have found no evidence that velocity affected the nature of the corrosion in the RHR and RCIC coolers.

However, water flow velocity almost certainly influenced the type, amount and physical form of the deposits in these coolers.

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R T A E FAIL RE ANALY I Briefly stated, the RHR lube oil coolers and the RCIC pump room unit coolers failed by a combination of microbiologically induced corrosion and chemical pitting corrosion mechanisms. Periods of standing in contact with stagnant, microbiologically active water allowed initial deposits to form on the tube surfaces. Underneath these deposits, anaerobic conditions allowed sulfate-reducing bacteria to produce sulfides from sulfate ions in the water. The microbiologically-generated sulfides initially attacked the metal surfaces.

The bare metal exposed in this way tended to inhibit further microbiological growth under the deposits. However, oxygen concentration cells now existed between the moist deposits next to the metal and the bulk water. The bare metal became anodic relative to the metal away from the deposits and pitting corrosion began'.

Chloride ions from the water concentrated in the pit through complex ion formation with copper ions produced through corrosion. Iron and manganese in the water supply also concentrated in and near the growing tubercles and pits. Iron deposits tended to reduce the pitting corrosion rate by inhibiting diffusion of water through the deposits.

Manganese also served in this role, but in some cases also increased the corrosion rate by catalyzing the electron transfer reactions within the pits and next to the metal surface.

This pitting corrosion eventually produced the through-wall failure of RHR lube oil cooler 2E-217C and the incipient failures of RHR lE-217B and RCIC pump room unit cooler lE-228A. The reasons for the less severe pitting and deposition observed in other RHR and RCIC coolers are related to differences in deposit compositions and operating conditions among these coolers:

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The following paragraphs of this section examine this pitting corrosion failure scenario in more detail.

Pi Ini Copper and 90:10 cupronickel are chosen for heat exchanger service because of their good mechanical and heat transfer properties and because of their outstanding resistance to corrosion in clean, flowing water. These metals are so stable in water that heat exchanger tubes that have been corroded under deposits can be safely returned to service after cleaning(4). However, it is well known that copper alloys are attacked by sulfides. Much work has been done to understand and to document the pitting corrosion of copper and 90:10 cupronickel that can occur in sulflde-contaminated water(4 5@.

Most of this work has been done in marine environments.

Ionic concentrations are, of course, quite different in a fresh water environment such as the ESW spray pond. Sulfide should normally not exist in this system. The difference is that the ESW spray pond is biologically very active and probably contains large numbers of sulfate reducing bacteria (SRB). This assumption is based upon the known lack of biocidal treatment in the pond, probable anaerobic conditions near the bottom of the pond and the established high levels of SRB in the ESW-B supply to RCIC cooler 1E-228B.

Water in the RHR lube oil coolers and the RCIC pump room unit coolers has been stagnant from 65 to 75 percent of the time (Table 10 and Figures 7A and 7B). During these stagnant periods, suspended solids, biological matter and soluble materials from the water, particularly iron, manganese and calcium salts, tended to precipitate on the tube surfaces. Some of these solids must have been moved every time the ESW water circulated, but over time, adherent deposits t

accumulated.

Sulfldic metabolic products from SRB in these deposits acted in the same way as sulfldes in contaminated sea water; they attacked the Page 36

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metal surfaces. These bacteria then either died or became inactive.

Pope et al(7) explained that little is known about MIC ori copper alloys in fresh water because of the known toxicity of copper ions to bacteria.

Schiffrin et al+) showed that aerobic organisms, e.g., Pseudomonas, can also induce pitting corrosion of copper alloys by forming deposits .

that lead to oxygen concentration cells and eventual destruction of the protective oxide layers on the metal.

Once bare metal had been exposed by microbiologically induced sulfide attack, standard under-deposit oxygen concentration cell

,corrosion became the driving force. Many authors have documented pitting corrosion on copper. During+) described several cases of pitting on copper beneath iron oxide deposits. The photographs in During's book look similar in some respects to those in this report.

The AWWA('@ explains pitting on copper water piping in great detail, with diagrams and electrochemical mechanisms. Quoting from this work, "Pitting (on copper) is characterized by the presence of tubercles, which are randomly distributed. The inside of the tube (contains) blue-green basic copper carbonate (Malachite). Under this layer is a brown layer of cuprite (cuprous oxide, Cu20), which is friable and easily spalled from the underlying copper metal. Typically, many pits at aH stages of development are seen, but only,a few have actually penetrated the wall thickness." This description seems to match quite well the the conditions in the failed RHR lube oil'ooler, 2E-217C.

Lyman and Cohen(>0) compared the chemical compositions of many water supplies associated with pitting failures in copper tubes.

The pH, chloride and sulfate levels in the ESW, as listed in Table 9, fall into Lyman.and Cohens'ange of maximum susceptibility to pitting.

However, the authors also point out that many successful applications of copper piping exist in waters with similar compositions. Chloride does tend to concentrate at anodic sites because of complex ion Page 37

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formation with newly released copper ions. This can further reduce the pH at the anodic site and increase the corrosion rate.

Eff f ulf r Irn Sulfides and sulfates may continue to influence the corrosion mechanism during the second, or concentration cell phase of pit growth. The AWWA manual(@ describes pit morphology in copper pipes. In the absence of sulfides, the AWWA claims that most pits are irregular in shape, straight edged and narrow. With sulQdes present (from the water, not from MIC), pits tend to be wider and shallower in nature. The mechanism described here is very similar to chloride-

.enhanced pitting corrosion of mild steel.

Both types of pitting described by the AWWA are clearly evident in the RHR lube oil cooler tubes. See, for example, Photographs 19,

~

23, 27, 30, 31, 33 and 34. In the ESW system, SRB obviously continue

~ ~ ~ ~

to exist in the deposits, although not in direct contact with the metal

~

surface. ~ It is entirely possible for sulfides generated by SRB

~

metabolism to continue to diffuse with the water and affect pit morphology as discussed by the AWWA. The fact that SEM/EDS analyses and the element maps in this report showed sulfur present at specific but'different locations in various pits and deposits may be the result of this effect. See Table 6 and Figures 23 through 29.

Iron found in the RHR lube oil cooler and RCIC pump room unit cooler deposits comes mostly from the makeup water to the spray pond, with additional contributions from iron accumulated in the pond and from possible corrosion of ESW transfer lines. Soluble iron in the water may be precipitated in the ESW system by chemical oxidation or by the action of iron oxidizing bacteria. These bacteria are often found to coexist with other bacteria in biologically active water systems.

t inside The XRD data (Table 7) show that iron in deposits was present entirely as magnetite. This is expected in low oxygen locations, i.e.,

and underneath tubercles.

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$1 characteristics of the speciQc deposits, magnetite may provide some

,barrier layer corrosion protection, or it may serve only to increase the size and number of the tubercles and therefore the intensity of pitting.

The presence of manganese, at the levels found in the Susquehanna deposits, can both aggravate and reduce 'itting corrosion. Manganese is a multivalent metal. It can exist in several oxidation states and can therefore act as an electron transfer agent to encourage electrochemical oxidation-reduction reactions. This, in effect, increases the corr'osion rate and particularly pitting corrosion under manganese-containing deposits(>>). At the same time, however, tightly adherent layers of manganese oxides can protect metal surfaces from contact with water. Manganese oxides are often suggested as products of biological metabolism in manganese-containing waters.

t Both of these mechanisms were involved'in the RHR lube oil cooler pitting corrosion. process. The RHR 2E-217C cooler showed little manganese in the deposits, but the deposits were crystalline, scaling and non-adherent in nature. Even the small amount of manganese found in this deposit (Table 5) can increase corrosivity by aiding oxidation-reduction reactions involving electron transfer, as explained above. The RHR lE-217A deposit contained much more manganese, but as explained in the inspection section above, these deposits were less scaling and more adherent in nature. Pitting attack was correspondingly less severe.

The variations in manganese content of the deposits may be part of the reason for the differences in condition of the various RHR lube oil coolers. The worst coolers (2C and 1B) are on the ESW B loop, while the coolers in the best condition (lA, 2A and 1D) are on the A loop. The ESW A and B loops must be considered as one system, so these differences are hard to explain. Prior to June 1989, the A loop ran more frequently and carried more water than the B loop and at about a 20 percent lower velocity. Possibly more manganese could-have deposited in the A loop under these conditions. The very high Page 39

Thomas M. Laronge, Inl-.

levels of manganese in the lE-217A and 2E-217B elbows remain unexplained.

n fRHR 1 r R I lr u rnikel It is interesting to compare the condition of the RHR lube oil coolers (type K copper) with the RCIC pump room unit coolers (90:10 cupronickel). The discussion in this report has centered on the RHR coolers because of the failure that occurred in 2E-217C and the near through-wall pits found in other RHR coolers. However, the RCIC coolers were not far behind. We measured a 90 percent through-wall pit in 1E-228A and a 60 percent through-wall pit in lE-228B (Table 4).

The flow velocity in the RCIC coolers was reported by PAL as about 2 to 3 feet per second. Water flows in both the RHR and RCIC coolers whenever the ESW pumps are running. RCIC 1E-228A is connected to the A loop and lE-228B to the B loop. RCIC 1E-228B and the ESW B inlet water line to this cooler showed the highest levels of microbiological activity of all the coolers tested. The manganese level in the deposit from RCIC 1E-228B was very low, similar to RHR 2E-217C.

It is clear that the pitting corrosion problem is just as serious in the RCIC room coolers as in the RHR lube oil coolers. This is important because the RHR coolers are the only copper coils in the ESW system; all other coolers are 90:10 cupronickel or other alloys.

Cupronickel and copper are both known for their excellent resistance to corrosion in clean, flowing water at neutral and alkaline pH.

However, cupronickel is more susceptible than copper to both general biofouling and MIC(>2).

This behavior has been observed and documented, but not

.explained very well. Copper (and 304 stainless steel) form passive, protective Alms that provide corrosion resistance. 90:10 cupronickel also forms passive surface films, and obtains additional corrosion Page 40

Thomas M. Loronge, Inc.

resistance from the electrochemical nobility of the alloyed surface. In the presence of a corrosive agent such as hydrogen sulfide from biological metabolism, and in the absence of oxygen needed to repair passive fQms, it is possible that films on the single component copper surface. might be more resistant to attack than those on the two component 90: 1'0 cupronickel surface.

0 Page 41

Thomos M. Larongt, Inc.

ENDI Page 42

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Thomas M. Laronge, Inc.

BIBLI RAPHY y

1. Claude D. Tapley, "Process Industries Corrosion." Texas, National Association of Corrosion Engineers, 1975.

2. R. James Landrum, "Fundamentals of Designing for Corrosion Control: A Corrosion Aid for the Designer." Texas, National Association of Corrosion Engineers, 1989.

3. K. I. Johnson and D. A. Neitzel, "Improving the Reliability of Open Cycle Water System: Applications of Biofouling Surveillance and Control Techniques to Sediment and Corrosion Fouling at Nuclear Power Plants." Washington, Division of Safety Review and Oversite, Office of Nuclear Reactor Regulation, U. S.

Nuclear Regulatory Commission, 1987.

'rthur

~ H. Tuthill, "Successful use of Carbon Steel, Copper Base Alloys and Stainless Steel in Service Water Systems in Other Industries." Presented at the EPRI Service Water System Reliability Improvement Seminar, Charlotte, North Carolina, October 1988.

5. H. A. Videla, M. F. L. de Mele, and G. Brankevich, "Assessment of Corrosion and Microfouling of Several Metals in Polluted 8

• 1 ." 81LNNN 44 8 . 1, 4 ty 1888.

6. D. F Schiffrin and S. R. de Sanchez, 'The Effects of Pollutants and Bacterial Microfouling on the Corrosion of Copper Base Alloys in Seawater." Quern i n, 41, No. 1, January 1985.

7. D. H. Pope, D. Tuques, P. C. Wayner, Jr. and A. H. Johannes, "Microbiologically Influenced Corrosion: A State of the Art Review." MTI Publication No. 13, Materials Technology Institute of the Chemical Process Industries, Inc., second edition, 1990.

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Thomas M. Laronge, Inc.

8. Evert D. D. During, rr i n A1 11 n f Illu r Hi ri V 1 2 New York, Elsevier Press, 1988.

9. AWWA Research Foundation, n rn 1 rr i n f W r Di ri n m pp. 337-365. Denver, AWWA Press, 1985.

10. W. Stuart Lyman and Arthur Cohen, "Service Experience With Copper Plumbing Pipe." M ri 1 Pr i n n P rf rm n V~1 11, No. 2, pp. 43-53, February 1972.

ll. Victor J. Linnenbom and Jeffrey J. Forshee, "Service Water System Experience at Beaver Valley Power Station." Presented at the Service Water System Reliability Improvement Seminar, Charlotte, North Carolina, October 1988.

12. David S. Hibbard, "Copper Alloy Tube Applications in Power Plant e Condensers." P w r En in rin, August 1981.

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LI F TABLE TABLE 1 RESULTS OF VISUAL INSPECTIONS OF SPECIMENS TABLE 2 RESULTS OF PHYSICAL MMBUREMENTS ON AS-RECEIVED SPECIMENS TABLE 3 RESULTS OF DEPOSIT WEIGHT DENSITY MEASUREMENTS TABLE 4 RESULTS OF PIT DEPTH SURVEYS TABLE 5 CHEMICALANALYSES OF DEPOSITS TABLE 6 SUMMIARYOF SEM-EDS ANALYTICALRESULTS TABLE 7 RESULTS OF DEBYE-SCHERRER X-RAYDIFFRACTION ANALYSIS OF DEPOSIT SAMPLES USING COPPER K-ALPHA RADIATION TABLE 8 RESULTS OF MICROBIOLOGICALANALYSES TABLE 9 RESULTS OF THE ANALYSIS OF ESW B WATER SUPPLY TO RCIC 1E-228B PUMP ROOM UNIT COOLER e TABLE 10 ESW AND RHR PUMP RUN TIMES, HOURS TABLE 11 RHR LUBE OIL COOLER FLOW VELOCITIES TABLE 12 COMPARISONS OF OBSERVATIONS AND PHYSICAL MEASUREMENTS Page 45

C(

I

TABL RESULTS OF VISUAL INSP NS OF SPECIMENS Thomos M. LoIonge, Inc.

Item Number Descri tion Photo No. Visual Ins ections of Interior Surfaces RCIC 1&228A Pump room unit cooler. 1,14,15.16, U orm thin brown deposits plus tubercles, also some 40, 41, 43 mse/tan deposits on surfaces. Green and red deposits beneath tubercles. Pits mostly hemispherical, some jagged and irre ular. No undercuttin . No eneral corrosion.

RCIC lE-228B Pum room unit cooler. 11,48,49 De osfts and fttfn sfmQar to lE-228A.

RHR lE-217A Lube oQ cooler. 13 Uniform thin de osits, no tubercles, ve sl ht fttin .

RHR lE-217A Lube oQ cooler, 90 degree 13,37,38,39 Apparently brass elbows. Black powdery deposit, some are 90 Degree Bends bends. metal. No visible corrosion under deposits, except pitting on copper tube (Photo No. 39).

~ RHR lE-217B Lu eo coo er,3 row ,20,21,2, Mos y smoo rown ac eposft, some a green Section 3B from top, 2nd coQ from 23,42,44,45 deposits. Large brown tubercles, 0.25 inch diameter and center. height. Under-deposit pits mostly hemispherical, no odd-shaped or ed-ed e pfts.

RHR lE-217C Lube o cooler. 7,28,29,30, Large amount o smooth brown/black deposit, right green 31,46,47 crystals around tubercles and pits. Sparkling silver/red crystals in bottoms of large shallow hemispherical pits (SEM Photo Nos. 46 and 47.

RHR2E-217A Lu e o coo er. 6 U orm rown, s to 1E-217B, ut muc sma er tubercles. No significant visible localized or general

'orrosion.

RHR2E-217B Lube oQ cooler. 8,9,10,12, Scattered black and green deposits, appear to ollow ow 32,33,34 pattern. No significant tuberculatfon. Hemispherical pits were Qlled with een and black deposits.

9 RHR2E-217B Lube oQ cooler, 90 degree 12,35,36 Apparently copper elbows. Smooth tan/black deposits. No 90 De eBends bends. visible localized or eneral corrosion.

10 - RHR2E-217C Lube oQ cooler. 2,17,18,19 Heavy grey/green scaly deposit, no smooth rown/black layer as in other coQs. Large tubercles covering green and red deposits. Many jagged and hemispherical pits, Most severe pfttfn of all RHR lube oQ coo coQs examined.

RHR2E-217D Lube oQ cooler. 4,5,24,25,26,27 U orm brown deposit, many small tubercles with green edges, green deposit below tubezeles. Shallow, Mund pits, less severe than other coolers.

Page 46

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TABLE 2 RESULTS OF PHYSICAL MEASUREMENTS ON AS-RECEIVED SPECIMENS Measured Typical Overall Outside Inside Wall Minimum Wall

,Length, Diameter, Diameter, Thfckness, Thickness +/-

Specimen Inches Inches Inches Inches Tolerance, Inches RCIC lE-228A Horizontal Split 0.637 0.529 0.055 0.049+ 0.004 RCIC lE-228A Vertical Split 20.3 0.635 0.531 0.052 0.049+ 0.004 RCIC lE-228B Horizontal Split 19.6 0.637 0.528 0.060 0.049+ 0.004 RCIC lE-228B Vertical Split 22.5 0.637 0.514 0.060 0.049 + 0.004 RHR lE-217A 90 D e Bends 2.3 to 2.5 0.980 0.760 0.098 Uncertain RHR 1E-217B-3B 16.0 0.873 0.741 0.071 0.065+ 0.0045 RHR 1E-217C 10.0 0.890 0.765 0.071 0.065+ 0.0045 RHR 2E-217A 14.0 0.855 0.750 0.058 to 0.070 0.065+ 0.0045 RHR 2E-217B-2 Varies Depending on 2nd Row From To S ecimen Considered 0.875 0.743 0.065 0.065+ 0.0045 RHR 2E-217B- Varies Depen on 2nd Row From Bottom S ecimen Considered 0.875 0.743 0.065 . 0.065+ 0.0045 RHR 2E-217B-2 2nd Row From Top Varies Depending on sA,B,C,D S ecfmen Considered 0.825 0.713 0.056 0.065+ 0.0045 RHR 2E-217B 90 D ree Bends 1.9 to 2.1 0.90 to 1.0 0.75 to 0.85 0.075 0.065 g 0.0045 RHR 2E-217C 16.5 0.850 0.718 0.075 0.065+ 0.0045 RHR 2E-217D 15.5 0.895 0.755 0.070 0.065+ 0.0045 Page 47

TABLE 3 RESULTS OF DEPOSIT WEIGHT DENSITY MEASUREMENTS~

De osit Wei ht Densi S ecimen m/ft2 m /mm2 RCIC lE-228A, Horizontal S lit 10.67 0.11 RCIC lE-228A, Vertical S lit 7.13 0.08 RCIC 1E-228B, Horizontal S lit 7.72 0.08 RCIC lE-228B, Vertical S lit 7.77 0.08 RHR lE-217A, 90 De ree Bends 15.40 0.16 RHR lE-217B-3B, 3rd Row From Top, 2nd Rin From the Inside 31.73 0.34 RHR lE-217C 24.07 0.26 RHR 2E-217A 5.25 0.06 RHR 2E-217B-2, 2nd Row From To 13.21 0.14 RHR 2E-217B-5, 2nd Row From Bottom 6.86 0.07 RHR 2E-217B, 90 De ree Bends 17.23 0.18 ~

RHR 2E-217C 37.90 0.41 RHR 2E-217D 27.25 0.29

'Calculated according to ASTM Standard D 3483-83 Method A Page 48

I Thomos M. Loronge, Inc.

TABLE 4 RESULTS OF PIT DEPM SURVEYS Estimated Estimated Maximum alculated Percent Through-Density of Pitting, Pit Depth, Wall Using Maximum Pit S ecimen Pits/Square Inch Inches Depth, Percent RCIC lE-228A, Horizontal S lit 5to 50 0.050 91 RCIC lE-228A, Vertical S lit 0.017 33 RCIC lE-228B, Horizontal S lit 0.017 28 RCIC 1E-228B, Vertical S lit 2to5 0.036 60 RHR lE-217A, 90 De ree Bends Essentiall Free of Local or General Attack RHR lE-217B-3B, 3rd Row From Top, 2nd Rin From the Inside 5to50 0.025 RHR 1E-217C: 25 to 300 0.013 18 RHR 2E-217A Essentiall Free of Local or General Attack RHR 2E-217B-5, 2nd Row From Bottom 0.007 RHR 2E-217B-2, 2nd Row From To 4to 50 0.025 38 RHR 2E-217B, 90 De ree Bends Essentiall Free of Local or General Attack RHR 2E-217C 1 to 200 0.028 37 RHR 2E-217D 0.015 Page 49

Thomos M. Lo,ronge, inc.

TABLE 5 CIIEMICALANALYSES OF DEPOSITS Data in WUeight Percent AllTests Run bv ICAP Exce t "

RHR 1E RHR 2E RCIC 1E ES%V Param "2'17A 217B RHR 1E RHR lE RHR 1E RHR 2E RHR 2E 2MB GR DX eter Elbow Elbow 217A 217C 217B-3B 217C 217C Hor.solit 2E-297A Il Fe 5.00 2.95 7.~D l '.02 0.96 0.86! 3.36 I 4O.8O Cu 10.19 9.53 70.30 49.54 57,90 80.30 72.59 0.02

'.11 l

'1.47 l l Mn 22,80 23.37  ?.07 4.98 0.67 1.22 0.89 ii 0.34

,.'.83 Zn I 2 66 3.94 0.79'.20 l 0. 17 0.25 0.30 i 0.27 i 0.08 4 29 0.68 0.77 031 0,12 Ca

'.~U i 3.14 0.20 0.27 0.06 1.40 i 2.08 l 4.95 4.48 O.8O 2.81 ii

'! 0.69 i

l 0.63 I

P 0,95 0.97 0.00 3.93 I 4.72 4.48 0.00 > 5.84 i 0.00 Al I ND 0.49

(

1.09 0.39 ! 0 22 0.21 0.41 f 0.38,'.86 Ba AD 0.63 ( 0.46 0.23 l 0,03 0.04 0.04 i 0.04 l 0.02 I

g l ND 0.47 I 0.29 O.22 ', 0.04 0.07 0.10 I 0,12 I 0.10 I .'4D O.o4 ~ 0.27 0.18 ! 0.03 0.04 0.08 il 0.09 i 0.63 i

Yia YiD 0.'2~ 0.04 0.26 i 0.05 0.26 10.00 i 0. 13 l 0.09

~T' IV 0.21 0.14 I) 0.08 0.05 l 0,01 <0.01 <0.01 1.24 I

<0.01 Cr <0.01 <0.01 ) <0.01 <0.01 l 0.01 <0.01 '0.01 i1 <0,01 l <0.01 Mo 0.14 0.15 I <0.01 0.02, <0.01 <0.01 <0.0'1, <0.01, <0.01 I

I Si02 ND 3.64 ~Di ND ND 1.07 'i ND ').80 SO4" l YiD YiD f 0.30 YiD i AD YiD 8.40 I! ND i 0.63 CO"" QT D 3.20 4D', ND XD 6.80 ill XD, 0.10

'i I ~l LOI (@:i II

'105C ND ND <

9.40 ND ii,

'AD ND 14.90 38.20 850C i YiD YiD i iuD I iiiD YiD 11.?0 i

'.10 12.50 i

I S Combustion to SO2 SO4 Estimate from total sulfur determination CO3 Yieutralization Page 50

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Thomas M. Laronge, Inc.

TABLE 6

SUMMARY

OF SEM-EDS ANALYTICALRESULTS Page1of 2 Fig. illumbers 'Aormal, iilet EDS MAPS Photos RHR Pum Location EDS Wt.% Atom % Intensitv I I I I

9 23 1E -2178-~8 !Deposit inside waterside I

pit 16.42 I 2d.O4 i 37.15 I I 83.58 I 73.96 I 100.41 10 23 ilE-2178-38 Waterside pit base Cl 6.75 11.45 I 27 81 I I Mn 0.65 I 0.71 2.17 I I I I I Fe 0.91 I 0.98 i 3.05 l I I

I CU 91.69 I 86.85 177,99 11 24 44 1B-217B-3BtDeposit inside waterside pit S 6.12 I I

11.39 16.12 i

I I Mn 1,43 I 1.55 I 5.15 I I I Fe 1.37 I 1.47 4.89 I I I I I I CU 91.08 I 85.59 I 187 80 24 I1E-2178-38! Waterside pit base 13.35 )

23.26 I 30.10 I I I Mn 2.17  ! 2'71 I 6.03 I I i I I I I I I Fe 1.SO i 1.81 I 4.93 I ' 72.72 133.72 I I Cu 82.67 '.

13 1 45 I lE-2178-38 IDeposit inside waterside pit S 3.57 i 6.05 I 10,12 I

I I I I Cl 15.93 II 24.47 I 56.67 I I I I Mn 1.07 I 1.06 I 3.40 I I I I I I I I Fe Z91I 2.84  ! 9.08 I I I lt Cu 76.52 65.58 ', 144.82 14 .I I1E-2178-38 iWaterside pit base S 0.00 I O.OO I 0.00 I I I I I Cl 0,24 I 0.43 I 0.89 I

I I I Mn 0,99 I 1.14 3.87 I I

'7 2.58 8.83 Fe 28 I Cli 96.48  ! 9585 I 211.92 15 I 76 46 I1E-217C Adjacent to waterside pit Fe 1.07 I 1.21 I I

I /

I I I Cli ,

98.93'98.79,'.75 196.91 16 I 26 11E-217 C IInside waterside I

pit base Fe 0.93 I 1.05 I 2.77 I Cu 99.07 I 98.95 I 167,81 Page 51

f

<Zp

ThOmaS M. Lo,rOnge, InC.

TABLE 6

SUMMARY

OF SEM-EDS ANALYTICALRESULTS Page 2of 2 Fig. Numbers Normal, Net EDS MAPS Photos RHR Pum EDS Wt.% Atom % Intensitv i I I I I I

17 I 27 11E 228A (Horizontal split

(

Cl 0.11 (

0.36 I ( (Deposit inside waterside pit ( Fe 3.79 ( 429 ( 'l2 85 I I I

I 1 I I CU 96.09 ( 95.51 I 184.95 18 27 I '1E-228A I

'Horizontal split Al 10.21 1358 (

18.40

( I I I i (Waterside pit base Si 43.48 55.57 ( 109.66 I

I I I S 5.97 6.68 (

13.55

( I i I I I I K 2.07 1.90 ( 8.91

( I I I i I I Fe 8.21 5.28 i 23.36 I I I CQ 30.05 16.98 55.19 48 (1E-228B (Vertical split Cl 0,35 (

'.61 I 1.33 I

(

,Adjacent to waterside pit Mn 1.47 5.89

( ( Fe 5.71 ( 6.39 i 7'7 <7 r (

I I Nii 5.01 I 1245 l CU 87.77 86.32 196,88 (Vertical split 6.14

'85 (1E-228B

'.34 20- ( S ( (

1 i I

,'Inside waterside pit base Cl 0,25 I 0.42, 0.70

'7 1 I I Mn 0.79 ( 0.87 ( 25 l I Fe 15.73 t 43.51 I

4.88 (

16.93,'.oo,'1.44 9.02 r l l Cu 75.50 ( i 119.11 I

21 ,29 ('1E-228B ,Vertical split I Cl 8.87 ', 14.70 r 35.50 I i (Adjacent to waterside pit r Mn 1.01 i 1.08 ' 3.86 I r I I I Fe 3.21 i D.D I 1210 I

I Ni 6.72 ', 6.73 17.48 I Cu 80.19 l i

'4.12 176.60

,1E-228B (Vertical split Fe 5.35 (

6.o4 t 17.22

(

I 'Inside waterside pit base Cu 94.65 ( 93.96 ( 173. 17 I I l 1 I II Element maps cover pit area for each specimen.

Page 52

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f

TABLE 7 RESULTS OF DEBYE-SCHERRER X-RAYDIFFRACTION ANALYSIS OF.

DEPOSIT SAMPLES USING COPPER K-ALPHA RADIATION Deposit Sample From RHR lE-217B-3B Line No. "d" Measured "d""'ables Compound 5.37 5.38 Cu OH 2 3.72 3.73 Cu OH)2 2.94 2.97 Fe304 2.68 2.69 Cu OH)2 2,53 2.53 Fe304 2.47 2.47 Cu20

.27 uOH2 2.14 2.13 Cu20 2.08 2.10 Fe304 10 1.74 1.71. Fe304 Deposit Sample From RHR lE-217C Line No. "d" Measured "d""'ables Compound 5.40 5.38 Cu(OH)2

2. 7 Fe3 2.47 2.47 Cu20 2.14 2.13 Cu20 1.73 1.71 Fe304 1.51 1.51 Cu20 1.46 1.48 Fe304 Deposit Sample From RHR 2E-217B, 90 De ree Bend Line No. "d" Measured "d""'ables Compound 2.95 2,95 Fe304 2.53 2.51 Fe304 2.43 2.47 Cu20 2.15 2.13 Cu20 1.95 1.95 Fe304 1.49 1.48 Fe304 Deposit Sample From RHR 2E-217C Line No. "d" Measured "d""'ables Compound 5.40 5.38 Cu(OH)2 3.73 3.73 Cu OH)2 3.00 2,97 Fe304 2.69 2.69 Cu OH2

.47 .47 2.13 2.13 Cu20 1.73 1.71 Fe304 1.51 1.51 Cu20 1.29 1.29 Cu20 10 0.98 0,98 Cu20

"'d" in angstroms Page 53

Thomas M. Lo,ronge, inc.

TABLE 8 RESULTS OF MICROBIOLOGICALANALYSES Total Total Live SRB Live APB Count SRB by On-Site by On-Site Sam le Tv e Units bv FITC bv IFA Culture Culture I I 1E 228 B Water ', Cells/mt t 3 SE+09 I 6.1E+06 i

>1.0E+07 i

>1.0E+07 RCIC room cooler l I I I I

I I

I I I I I I I I I I I I I I I 1E 228 B Deposit lCells/gm l 3.8E+07 l 1.9E+05 I >1.0E+07 I >1.0E+07 I I RCIC room cooler I I I I t

I I I 7A Deposit JCells/gm ~)

'1.8E+08 I I

8.2E+06 i >'1.0E+06 ' > 1.0E+05 oil cooler I' l I I I I I I I I I I I I I I I I 2E 217 B Deposit ICells/gm i I

>'1.0E+04 I > 1.0E+03 RHR oil cooler I I

I I

I I

I I I I 1 l I I

I I I

,I I I 2E 217 C Deposit lCells/gm l ~9E+07 I <9.8E+04 i > 1.0E+04 l >1.0E+04 I I I I RHR oil cooler 'I I I I I I I I I I 1 I I I 2E 297 A Deposit',Cells/gm ', 4.5E+07'1.2E+06 I

> 1.0E+05 '>1.0E+04 DX Condenser I I Page 54

Thomas M. Laronge, Inc.

TABLE9 RESULTS OF THE ANALYSISOF ESW B XVATER SUPPLY TO RCIC 1E-2288 PUMP ROOM UNIT COOLER Sam le Taken June 9,1990 Parameter As Method PPM I i 1 pI-I i pH I pH 7.7 I

Total alkal. < CaCO3i Titrationi 183.0 Conductivity 'umhos,'eter 587.0 i I I i 1 i Aluminum i Al ICAP (0.10 I I Barium , Ba ICAP (0.10 0

i Calcium ', CaCO3i ICAP 150.00 Copper 1 Cu i ICAP i 0.04 Iron 'Fe 0.74 Magnesium i CaCO3i ICAP i 55.60 I

Manganese , Mn ICAP i 0.75

' ICAP 5.75 Potassium I 1 Silica ~ Si02 ICAP 4.75 Sodium gT~ ICAP 18.80 Zinc Zn ICAP i 0.28 t

Chloride Cl IC 33.30 Fluoride "F IC 0. 15 Ylitrate]nitrite IC 10.~~

Sulfate I SO4 IC 53.60 LSI at 80F :0.4 LSI a<<OOF +0.6 LSI at 110F :0.7 0

Page 55

0 TABLE ESW AND Iilll<PUMI'I IML'S, I IOUI(S Page 1 of 2 Loop A Iuop l3 Assumed Assumed l<l Ii< Pumps Moutlt ESW-A ESW-C 'l'otal FSW-I3 l>W-I) Total 1A 113 IC 1D 2A 213 =-

2C 20 Aug46 '407 407 407 0 57- 57 Sep-S6 448 447 .448 423 1 424 Oct-S6 431 431 447 74 521 Nov-86 l62 162 162 60 436 496

'ec-86 213 2l1 213 105 21 126 Note: RHR pump data for April, 1987 include Jan-S7 48 47 48 SS 7 95 January through April, 1987.

I'el)47 72 67 72 52 19 71 Mar47 89 89 89 31 1'I 42 Apr-S7 355 346 355 320 64 384 10 54 220 30 177 4 15 4 May47 173 172 173 S1 10 61 0 10 0 6 9 0 0 0 Jun-87 166 165 166 89 12 101 0 30 8 21 8 3 0 '

Jul47 190 190 190 106 2 108 0 62 13 29 2 .0 3 3 Aug-87 l50 150 150 108 10 118 0 44 16 10 2 7 0 2 Sep-87 352 373 373 435 18 453 47 20 122 l3 -2 2 11 0 Oct-87 569 555 569 553 34 587 4 145 3 130 4 0 0 3 Nov47 232 238 238 384 15 399 l72 122 214 3 0 2' 2 Dec47 337 337 337 156 22 178 100 3 0 124 1 1 1 13 Jan-88 7l 71 71 41 11 52 11 1 1 3 6 0 0 I'eb48 36) 36 36 8 12 0 0 0 5 '2 0 0 0 Mar-88 535 S96 596 6 508 514 109 121 1 0 229 0 144 0 Apr-SS 802 741 802 28 611 639 1 4 0 4 175 276 4 0 May-88 642 644 644 41 39 80 25 0 0 0 5 2 4 537 Jun-88 54S 5-lS 548 182 29 21'1 99 24 0 80 137 22 65 210 Page 56

~ +a %

TABL ESW AND Rl IR PUMP 10 IML'S, IIOIJI(S Page 2 of 2 I.oop 13 Assumed Assumed I<Ill< Pumps Mon tb LS'W-A ESW-C 'I'otal I'.SW-}3 le-D Total IC 1D 2A '28 2C 2D Jul-88 l08 108 108 56 81 13 17 0 6 10 7 Aug-88 134 133 l34 96 17 113 29 27 11 '12 1 2 Sep-88 63 74 74 78 5 20 15 5 1 9 Oct-88 58 57 58 36 7 43 12 15 0 6 0 6 Nov-88 47 37 47 33 2 35 10 14 0 5 0 8 Dec-88 O'I ,.40 41 43 4 47 15 13 3 0 0 5 Jan-89 loo 100 100 141 31 172 52 71 34 34 0 5 Feb-89 l68 168 168 26 14 40 112 7 3 11 7 2 Mar 89 162 162 162 137 7 144 42 22 1 2 54 1 86 Apr 89 506 507 507 166 89 255 387 0 51 0 0 0 0 May-89 607 607 607 ~D2 83 335 213 89 5 201 0 8 0 Jun-89 360 399 759 98 50 241 0 0 0 0 Jul-89 90 42 132 81 40 121 78 0 0 0 0 0 Aug-89 76 59 135 l04 16 120 1 0 1 8 0 Sep-89 511 21 532 434 101 535 59 0 383 8 42 8 Oct 89 232 678 405 274 679 3 0 105 326 6 lo No~-89 432 124 556 174 355 529 1 1 'l91 217 17 0 Dec 89 107 67 174 57 153 210 3 0 5 0 0 Jan-90 39 83 41 43 84 3 0 1 . 1 0 Feb-90 314 151 465 315 52 367 l85 14 24 97 Mar-90 128 131 259 146 42 188 2 2 3 0 0 Apr-90 71 56 l27 53 62 ll5 6 3 4 1 3 iVfay-90 100 32 l32 100 26 126 Page 57

Thomas M. Laronge, Inc.

TABLE 11 RHR LUBE OIL COOLER FLOW VELOCITIES Feet per second RHR Pum 4 Jun-86 to A r-87 A r-87 to Jun-89 Jun-89 to Jun-90 ESW Loop A I 8.0 8.0 1D 9.0 8.0 Q2 2A 9.0 8.0 7.3 2D 10.5 e ESW Loop B~,'B i

9.6 9.5 1C 10.8 92 2B 10.8 8.0 2C 12.6 8 loop data for June 1986 through June 1989 calculated as 20'Po higher than corresponding A loop data.

8 loop data for June 1989 through June 1990 are actual measurements.

Page 58

Pa Thomos M. Lcxronge, Inc.

TABLE 12 COMPARISONS OF OBSERVATIONS AND PHYSICAL MEASUREMENTS Page l of 2 Pit Density Deepest Pit Dep. Wt.Dens.

Coolers Pits/s .in. Inches mn/s .ft. Observations I I I I I ESW Loo A I I I I I I I I l RHR 1E-217A Very low, not l Not measured ) Not measured )Uniform thin deposit.

measured. l I

'very slight pitting.

I RHR 1E-217D Not tested. LW Not measured )

Not measured )iNot tested. LW reported reported little I I 'light general oxidation I I I to no pitting. I I Iw/ green coloration.

I l 1 I I 2E-217A Very low. not I Not measured I IUniform brown deposit, I I measured. I l ,no significant tubercu-I l Ilation or pittin~.

I I I I I I RHR 2E-217D 0.015 27,~D IUniform brown deposit, I I Imany small tubercles.

I I I I

',shallow round pits.

I I I I I RCIC 1E-228A 5to50 0.050 I 10.67 lUniform thin brown horiz. split I I I

,'deposit with tubercles, I

I ~hemispherical and I I I I

,'irregular pits, I I I I RCIC 1E-228A 0.017 7.13 ,Uniform thin brown vert. split I I

I I

,'deposit with tubercles, I I Ihemispherical and I I I I ',irregular pits.

I I I I I I ESW GRDX Not measured. l .iot measured I Not measured ,Heavy scale R slime. no I

2E-297A I visual heavy ,'visible pitting.

Page 59

Thomos M. Lo,ronge, Inc.

TABLE 12 COMPARISONS OF OBSERVATIONS AND PHYSICAL MEASUREMENTS Page'2 of 2 Pit Density Deepest Pit Dep.WVt.Dens.

Coolers Pits/s .in. Inches 'm/s .ft. Observations

<< I I <<

~ESNV L B <<

<< I RHR 1E-2178 5 to50 0.025 ) 31.73 <<Smooth brown/black and

) <<

I

,'flaky green deposits,

<<large tubercles and I

I <<

,hemisperical pits.

I << <<

<< 1 RHR-1E-217C 25 to 300 0.013 ) 24.07 <<Heavy brown/black deposit, large tubercles I <<and hemispherical pits.

I RHR 2E-2178-2 i 4 to 50 0.0~> <<13.21

'Scattered black/green

,deposit, no significant j 'tubercles. hemispherical I <<pits.

'.86 RHR 2E-2178-5 I 0.007 <<Scattered black/careen

, deposit. no significant I

'tubercles. hemispherical

<< "pits.

RHR 2E-217C l to 200 0.028 <<37.90 'Failed tube. Heaw scaly

,deposit. many jagged 8r.

,'hemispherical pits.

RCIC 1E-2288 0.017 ',

7.72 ,Uniform thin brown horiz. split I deposit with tuhercles.

hemispherical and

'irregular pits.

'E-2288 2 to 5 ,

0.036 /.77 ;Uniform thin brown split deposit with tubercles.

I

-hemispherical and

'irregular pits.

i

'I >

lt

Thomo,s M. Laronge, lnl-.

LI T FFI RE FIGURE 1 SKETCH OF VERTICAL, HIGH THRUST INDUCTION MOTOR GEH-3298 FIGURE 2 COMPARISON OF DEPOSIT COMPOSITIONS FIGURE 3 OFF-SITE MICROBIOLOGICALANALYSES FIGURE 4 ESW ALKALINITY,CALCIUM 8t CONDUCTIVITY'SW FIGURE 5 TURBIDITYAND pH FIGURE 6 ESW LANGELIER INDEX DATA FIGURE 7A PERCENT ESW AND RHR PUMP RUN TIMES-ESW LOOP A FIGURE 7B PERCENT ESW AND RHR PUMP RUN TIMES-ESW LOOP B FIGURE 8A RHR LUBE OIL COOLER FLOW VELOCITIES-ESW LOOP A FIGURE RHR LUBE OIL COOLER FLOW VELOCITIES-ESW LOOP B 9 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR 8B'IGURE 1E-217B-3B DEPOSIT INSIDE WATERSIDE PIT FIGURE 10 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR lE-217B-3B WATERSIDE PIT BASE FIGURE 11 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR lE-217B-3B DEPOSIT INSIDE WATERSIDE PIT FIGURE 12 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR 1E-217B-3B WATERSIDE PIT BASE FIGURE 13 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RHR 1E-217B-3B DEPOSIT INSIDE WATERSIDE PIT FIGURE 14 DISPERSIVE X-RAY SPECTROSCOPY OF RHR

'NERGY lE-217B-3B WATERSIDE PIT BASE FIGURE 15 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RHR 1E-217C ADJACENT TO WATERSIDE PIT FIGURE 16 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RHR lE-217C 'NSIDE WATERSIDE PIT BASE FIGURE 17 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RCIC lE-228A HORIZONTAL SPLIT DEPOSIT INSIDE WATERSIDE PIT Page 61

Thomas M. Larongt, Inc.

FIGURE 18 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC 1E-228A HORIZONTAL SPLIT WATERSIDE PIT BASE FIGURE 19 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT ADJACENT TO WATERSIDE PIT FIGURE 20 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228 VERTICAL SPLIT INSIDE WATERSIDE PIT BASE FIGURE 21 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT ADJACENT TO WATERSIDE PIT FIGURE 22 ENERGY DISPERSIVE X-HAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT INSIDE WATERSIDE PIT BASE FIGURE 23 ELEMENT MAPS, RHR 1E-217B-3B FIGURE 24 ELEMENT MAPS, RHR lE-217B-3B FIGURE 25 ELEMENT MAPS, RHR 1E-217B-3B FIGURE 26 ELEMENT MAPS, RHR lE-217C FIGURE 27 ELEMENT MAPS, RCIC lE-228A, HORIZONTAL SPLIT FIGURE 28 ELEMEKI'APS, RCIC 1E-228B, VERTICAL SPLIT, TOP SECTION FIGURE 29 ELEMENT MAPS, RCIC lE-228B, VERTICAL SPLIT, BOTTOM SECTION Page 62

Thomas M. Laronge, Inc.

Figure 1 Sketch of Vertical, High Thrust Induction Motor GEH-3298 Motor Shaft Nuts and Top Cap Lockwashers Journal Sleeve and Thrust Bearing Oil Level D C B.A 1 CEXEXED Cooling Water 2 CDXXED Outlet 3 tXXXXED 4Q3XXED 5 CEXE3XD 6 CE3XXEO Cooling Water Inlet Six rows with four each, co-planar cooling coils Stator Frame Page 63

t

$ i I

~4

FIGURE 2 0 3

COMPARISON OF DEPOSIT COMPOSITIONS 0 0

0 (Q

CP A

z 0 e ec; K 4 0

0)

I-K Q

0-1A 1C 1B 2C RHR LUBE OIL COOLERS

[IIIFe gQ Mn ~ ~ Jca s Page 64

1 4'

~

FIGURE 3 OFF-SITE MICROBIOLOGICALANALYSES I E+09-1E+08=

v3

~ 1E+07- >cg G pX K jw.

UJ 0 /

V) 1E+06=

UJ

)a~

1E+05=

1E+04-1E 217 A 2E 217 C 1E 228 B 2E 297 A HEAT EXCHANGER DEPOSlTS QQ TOTAL BACTERIA II SULFATE REDUCERS Page 65

I FlGUR 4 ESW ALKALINITY,CALCIUM 8 CONDUCTIVITY 800 800 700 700 Conductivity O 0

O OJ O 600 600 E

E .500 L

500 400 400 O Calcium O

300 300 l-O Z 200 Cl 200 z 0

Q 100 100 Alkalinity 0 r-a--i- -,- r 1989 02/06 04/11 a r T a t- 7 a t- w ~

1990 05/26 07/11 08/09 09/06 11/03 01/03 t- r w w. r v w 03/08 05/15 06/02 r 0 06/11 MONTHLY DATA, 1989 TO PRESENT Page 66

,r FIGUR 0 ESN/ TURBIDITYAND pH 10 9

pH 0 9 03 8

7 6

5.

Turbidity 4

3 2.

1.

1989 I990 0 '1 t t r T 'f 1 i l 7 T l I I 7 T I I I 1 T I I 02/06 04/11 05/26 07/11 08/09 09/06 11/03 01/03 03/08 05/15 06/02 06/1 I MONTHLY DATA, 1989 TO PRESENT Page 67

FIGU 6 ESW LANGELIER INDEX DATA 100 TEMPERATURE

-80 4 60

>C LLI LU C3 a z 3. 40 CL" CC LLl I

2 -20 (g LLI LSI CL

-0 LLI 0 -20

-1 1989 T I I r v t g q r T' s; r 1990 r w 02/06 04/11 05/26 07/11 08/09 09/06 11/03 01/03 a w 03/08 r

05/15 T'

06/02 s a 06/11

-40 MONTH Y DATA, 1989 TO PRESENT Page 68

17 '4

~I 4

'I tf 0

'I ~ l~

~1 II

Thomos M. Laronge, Inc.

FIGURE 7A PERCENT ESW AND RHR PUMP RUN TIMES ESW LOOP A 60 50 I=

4o Z

30 O 20 10 0.

1987 1988 1989 1990

'm'ESW-A RHR-2A ~

YEAR gg RHR-1A RHR-2D 1 RHR-1D I

FIGURE 7B PERCENT ESW AND RHR PUMP RUN TIMES ESW LOOP B 60 UJ 50 I-40 30 z.'O CC LLI 10 0

1987 1988 1989 1990 YEAR

' ESW-B gg RHR-1B m RHR-1C I

~

I FQ RHR-2B ~ RHR-2C Page 69

e)

I i'n

~ gh

'I C

4

~ E%

,Thomas M. Laronge, Inl-.

FIGURE BA RHR LUBE OIL COOLER FLOW VELOCITIES ESW LOOP A z0O t4 0 12 10 8

6 4

2 0

Jun-86 to Apr-87 Apr-87 to Jun-89 Jun.89 to Jun-90 TIME INTERVALS, 1986-1990 im RHR-1A gg RHR-1D m RHR-2A gg RHR-2D e b FIGURE BB RHR LUBE OIL COOLER FLOW VELOCITIES ESW LOOP B O

0 t4 0 t2 10 8

6 4

2 0 0 Jun.86 to Apr-87 Apr-87 to Jun-89 Jun.89 to Jun-90 TIME INTERVALS, 1986-1990 I m RHR-1B + RHR-1C m RHR-2B gg RHR-2C Page 70

J fl 4P 0

Thomas M. Laronge, Inc.

FIGURE 9 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR 1E-2178-3B DEPOSIT INSIDE WATERSIDE PIT Iq4~>~

0'~ 'i~aJ I~

l~ l CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Cl 16.42 26.04 37. 15 83.58 73.96 100.41 Page 71

Thomos M. Laronge, Inc.

FIGURE 10 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RHR lE-217B-3B WATERSIDE PIT BASE

'cC X

CALCULATED.RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Cl 6.75 11.45 22.81 Mn 0.65 0.71 2. 17 0.91 0.98 3.05 91.69 86-.85 177.99 Page 72

Thomas M. Lo,range, Inc.

FIGURE 11 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR lE-217B-3B DEPOSIT INSIDE WATERSIDE PIT CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit S 6. 12 11.39 16. 12 Mn 1.43 1.55 5. 15 Fe 1.37 1.47 4.89 91.08 85.59 187.80 Page 73

QC W'

Thomas M. Laronge, Inc.

FIGURE 12 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR lE-217B-3B WATERSIDE PIT BASE

~/PAJQJ+a r~

CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit S 13;35 23.26 30. 10 Mn 2. 17 2.21 6.03 Fe 1.80 1.81 4.93 82.67 72.72 133.72 Page 74

4

~ tf l I ~

I'f'P

Thomo,s M. Lo,ronge, Inc.

FIGURE 13 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR 1E-217B-3B DEPOSIT INSIDE WATERSIDE PIT j

+l(lpVl~

~

Q

)0/'ALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit S 3.57 6.05 10. 12 Cl 15.93 24.47 56.67 Mn 1.07 1.06 3.40 Fe 2.91 2.84 9.08 76.52 65,58 144.82 Page 75

l Thomos M. Laronge, Inc.

FIGURE 14 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RHR 1E-217B-3B WATERSIDE PIT BASE YCAYM Y

CO V~

CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit S 0.00 0.00 0.00 Cl 0.24 0.43 0.89 Mn 0.99 1. 14 3.87 Fe 2.28 2.58 8.83 96.48 95.85 211,.92 Page 76

)h 0

Thomo,s M. Laronge, Inc.

FIGURE 15 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RHR lE-217C ADJACENT TO WATERSIDE PIT CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Fe 1.07 1.21 3.75 98.93 98.79 196.91 Page 77

Thomas M. Laronge, Inc.

FIGURE 16 ENERGY DISPERSIVE X-HAYSPECTROSCOPY OF RHR lE-217C INSIDE WATERSIDE PIT BASE j(f) ~f Vthlpstv sYhg~

hC

, ~ h'l~~>'qg>vy < ~ Ol U OJ U

Y/h'~<0~4 LP ~'A,~g4pg~ ~

CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Fe 0.93 1.05 2.77 99.07 98.95 167'.81 Page 78

Thomo,s M. Lo,ronge, Inc.

FIGURE 17 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RCIC 1E-228A HORIZONTAL SPLIT DEPOSIT INSIDE WATERSIDE PIT

'le hC CA Ch hC Ca 1'C hC IJ m 4l LJ U OJ U

CALCULATED RESULTS FROM STANDABDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Cl 0.11 0.20 0.36 Fe 3.79 4.29 12.85 96.09 95.51 184.95 Page 79

J' Thomas M. Laronge, Inc.

FIGURE 18 ENERGY DISPERSIVE X-RAY SPECTROSCOPY OF RCIC lE-228A HORIZONTAL SPLIT WATERSIDE PIT BASE

'le VA 4t V U

4hV Q~+~

CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit 10.21 13.58 18.40 Si 43.48 55.57 109.66 S 5.97 6.68 13.55 2.07 1.90 8.91 Fe 8.21 5.28 23.36 30.05 16.98 5519"=

Page 80

~ ~3 n = ~ ~ ~,y'\

l~'I Vl + P

Thomo,s M. Lo,range, Inc.

FIGURE 19 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT ADJACENT TO WATERSIDE PIT C CA V

5 VU CO LJ C 5C

/~)'i E5 X J('~ Y M/

~ ~

lpga(g ~

C

'~Pi.y 4I

~ ~

~'~~, v U gpss l~s,'ig <e CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit CI 0.35 0.61 1.33 Mn 1.47 1.67 5.89 Fe 5,71 6.39 22.57 Ni 4.70 5.01 12.45 87.77 86.32 196.88 Page 81

tl ~

Vl

Thomo,s M. Larongt, inc.

FIGURE 20 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT INSIDE WATERSIDE PIT BASE V

bC EI U

CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit S 2.85 5.34 6.14 Cl 0.25 0.42 0.70 Mn 0.79 0.87 2.25 Fe 15.73 16.93 43.51 Ni 4.88 5.00 9.02 Cu 75.50 71.44 119.11 Page 82

Thomos M. Loronge, inc.

FIGURE 21 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT ADJACENT TO WATERSIDE PIT bC C V CA

~>>iy i=

ii+(<i)J, hC hC Ap 4t 4(~<i,rg CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Cl 8.87 14.70 35.50 Mn 1.01 1.08 3.86 Fe 3.21 3.37 12. 10 Ni 6.72 6.73 17.48

80. 19 74. 12 176.60 0

Page 83

Thomo,s hh. Lo,ronge, Inc.

FIGURE 22 ENERGY DISPERSIVE X-RAYSPECTROSCOPY OF RCIC lE-228B VERTICAL SPLIT INSIDE WATERSIDE PIT BASE Vi DV CALCULATED RESULTS FROM STANDARDLESS ANALYSIS Normalized Weight Atomic Net Element Percent Percent Intensit Fe 5.35 6.04 17.22 94.65 93.96 173. 17 Page 84

I ~

FIGURE 23 ELEMENT MAPS, RHR 1E-2178-38 I.EG END S CI Mn Fe Page 85

~ I~

J ~

I gggmgg~i(g~igggg ;pygmy gj"ggpj+igg% IHN

~ I

~gg )gpg~i +iGQ Ncjm ggjjg gggigJJ gg I%I%

I IGURE 24 ~

EI.EMENT MAPS,,RHR 1 E-2178-38 I.EG END S CI le Page 86

I~IGURE 25 ELEMENT MAPS, RHR lE-2178-38 LEGEND S C1 Mn Fe Page 87

FIGURE 26 ELEMENT MAPS, RHR 1E-217C LEGEND S C1 Mn, Ie Page 88

FIGURF 27 ELEMENT MAPS, RCIC .1E-228A; HORIZONTAI SPLIT LEGEND

.S C1 Mn Fe.

Page 89

FIGURE 28 EI.EMENT MAPS, RCIC lE-2288, VERTICAI SPLIT, TOP SECTION LF.G END S .CI Mn Fe Page 90

0

~ S liiiiQSSRR,fan% F498 Riiiii55iRRf..&lkNQ

~

y p

, ~

lQRi55RRSRQ l%%

biiQRMWf: ~M FIGURE 29 EI.FMENT MAPS, RCIC lE-228B, VERTICAI SPLIT, BOTTOM SECTION .

LEGEND CI Mn. Ie Page 91

Thorn M. j.aronge, Inc.

LISI'F PHOTOGRAPHS Approximate Magnification Photograph As Printed, Desi nation Diameters S ecimen Desi nation and Descri tion of Photo a hs 0.3 RCIC lE-228A, As-Received.

0.3 RHR 2E-217C, As-Received.

0.4 RHR 1B-3B (lE-217B-3B), As-Received. "3B" Signifies the Third Ring From the Top and the Second Row in From the Inside Diameter.

0.4 RHR 2E-217D, As-Received.

0.4 RHR 2E-217D, As-Received.

0.4 RHR 2E-217A, As-Received.

0.6 RHR lE-217C, As-Received.

0.3 RHR 2E-217B, As-Received.

0.3 RHR 2E-217B, As-Received.

10 0.3 RHR 2E-217B, As-Received.

0.3 RCIC 1E-228B, As-Received.

12 0.3 RHR 2E-217B, As-Received.

13 0.3 RHR- lE-217A, As-Received.

14 '5 1.9 RCIC lE-228A, Interior View of Section of Vertical S lit Tube.

1.9 RCIC lE-228A, Interior View of Section of Vertical. Split Tube, as Seen in Photo ra h No. 14, After Sand Blastin .

Page 92

Thomas M. Laronge, Inc.

LIST OF PHOTOGRAPHS (Continued)

Approximate MagniAc ation Photograph As Printed, Desi nation Diameters S ecimen Desi nation and Descri tion of Photo ra hs 16 4.7 RCIC lE-228A, Close Up View of Interior Section of Vertical Split Tube, as Seen in Photo ra h No. 15, After Sand Blastin .

17 2.3 RHR 2E-217C, Close U View of Interior Surfaces.

18 2.3 RHR 2E-217C, Close U View of Interior Surfaces.

19 RHR 2E-217C, Close Up View of Typical Interior Surfaces, After Sand Blastin .

20 RHR 1E-217B-3B, View of Interior Surfaces, After Sectionin .

21. 2.4 RHR lE-217B-3B, Close Up View of Interior Surfaces,-as Seen in Photo ra h No. 20, After Sectionin Note: Dama ed Wall is Evident.

22 2.0 RHR lE-217B-3B, View of Interior Surfaces of a Small Section of Pi e, After Sectionin .

23 2.0 RHR 1E-271B-3B, View of Interior Surfaces of a Small Section of Pi e, as Seen in Photo ra h No. 22, After Sand Blastin .

24 1.0 RHR 2E-217D, View of Interior Surfaces, After Sectionin .

25 2.4 RHR 2E-217D, Close Up View of Interior Surfaces, as Seen in Photo ra h No. 24, After Sectionin .

26 2.4 RHR 2E-217D, View of Interior Surfaces of a Small Section of Pipe, After Sectionin .

27 4.3 RHR 2E-217D, Close Up View of Typical Interior Surfaces of S ecimen 2D, After Sand Blastin .

28 2.1 RHR lE-217C, View of Interior Surfaces of a Small Section of Pi e.

29 2.3 RHR lE-217C, View of Interior Surfaces of a Section of Pi e.

Page 93

~'

Thomas M. Loronge, Inc.

LISI'F PHOTOGRAPHS (Continued)

Approximate Magnification Photograph As Printed, Desi nation Diameters S ecimen Desi nation and Descri tion of Photo a hs 30 1.6 RHR 1E-217C, View of Interior Surfaces of a Section of Pipe, After Sand Blastin .

3.8 RHR lE-271C, Close Up View of Typical Interior Surfaces of 1C, After Sand Blastin .

1.6 RHR 2E-217B, View of Interior Surfaces of a Small Section.

33 1.6 RHR 2E-217B, View of Interior Surfaces, as Pictured in Photograph No. 32, After Sand Blastin .

34 4.7 RHR 2E-217B, Close Up View of Interior Surfaces, as Pictured in Photo a h No. 33, After Sand Blastin .

1.2 RHR 2E-217B, View of Interior Surfaces of Two 90 Degree Bends, After Sectionin .

36; 1.6 RHR 2E-217B, View of Interior Surfaces of One 90 Degree Bend, as Seen in the To of Photo ra h No. 35, After Sand Blastin .

37 1.2 RHR 1E-217A, View of Interior Surfaces of Two 90 Degree Bends, After Sectionin .

1.6 RHR lE-217A, View of Interior Surfaces of One 90 Degree Bend, as Seen in the Bottom of Photo ra h No. 37.

1.6 RHR lE-217A, View of Interior Surfaces of One 90 Degree Bend, as Seen in Photo ra h No. 38, After Sand Blastin .

40 11.0 RCIC lE-228A, View of Irregular Crater Before Removal of Overlying Material. Overlying Material was Removed to Prepare the Pit for Biolo ical Examination.

41 12.5 RCIC lE-228A, View of Irregular Crater, as Seen in Photograph No.

40, After Removal of Overlying Material. This Pit was Biologically Examined to Determine the Extent of Bacterial Contamination.

Page 94

Thomo,s M. Lo,ronge, Inc.

LIST OF PHOTOGRAPHS (Continued)

Approximate Magnification Photograph As Printed, Desi ation Diameters S ecimen Desi nation and Descri tion of Photo ra hs 42 15 RHR 1E-217B-3B, SEM Photograph of Typical Pit. Element Mapping and EDS Were Performed on this Pit.

15 RCIC lE-228A, Horizontally Split Section, SEM View of Typical Pit as Seen on the Interior Surfaces of 1E-228A. Element Mapping and EDS Were Performed on this Pit.

44 15 RHR lE-217B-3B, SEM Photograph of Typical Pit. Element Mapping and EDS Were Performed on this Pit.

45 15 RHR lE-217B-3B, SEM Photograph of Typical Pit. Element Mapping and EDS Were Performed on this Pit.

46 15 RHR lE-217C, SEM Photograph of Pit Containing Crystalline De osits. Element Ma in and EDS were Performed on this Pit.

47 350 RHR lE-217C, Close Up SEM Photograph of Crystalline Deposits, as Seen in Photo a h No. 46.

48 150 RCIC lE-228B, Top Half of Vertically Split Tube, SEM View of Small Pit. Element Ma in and EDS Were Performed on this Pit.

15 RCIC lE-228B, Bottom Half of Vertically Split Tube, SEM View of Pit.

Element Ma in and EDS Were Performed on this Pit.

Page 95

Thomas M. Laronge, inc.

POST OFFICE BOX 338 ~ CALIFON. NEW JERSEY 07830 ~ i201] 832-5097 ~ FAX t201) 832-9775 ARTHUR J. FREEDMAN, Ph.D.

Executive Vice President June 12, 1990 Mr. Raymond S. Tombaugh Prospect Engineer Pennsylvania Power and Light Company Two North Ninth Street Allentown, PA 18101 Sub)ect: Preliminary Report of Some Susquehanna ESW Cooler Inspections

Dear Mr. Tombaugh:

his letter constitutes our preliminary report of our study of pitting orrosion in the Susquehanna ESW system coolers.

Briefly, we have determined that the root cause of the pitting is conventional under-deposit corrosion aggravated by the presence of high levels of manganese in the deposits near the corrosion sites. Microbiologically-influenced corrosion (MIC) is a contributing factor that may have aggravated the attack in some coolers, but MIC is not the root causa of the problem. Details follow.

We arrived at the PP&L Allentown office at about 11:30 AM on Friday, June 8, 1990. After discussions with Lou Willertz and Ray Tombaugh, we went to the Susquehanna plant for required training.

Late Friday night, we inspected the 2E-217C RHR oil cooler coil. Over the next two days (Saturday and Sunday), we inspected the following equipment:

1. 1E-217A RHR Oil Cooler Coil

2. 2E-217B RHR Oil Cooler Coil

3. OE-507D Diesel Generator Jacket Water Cooler

4. OE-533D Diesel Governor Cooler

5. OE-505E1,2D Diesel Generator Intercooler

6. 1E-228B RCIC Pump Room Unit Cooler

7. 1E-228A RCIC Pump Room Unit Cooler

8. 2E-297A ESW GR DX System Condenser llowing is a summary of our data and the conclusions we have drawn from our rk to date.

Quality for Industry

III Thomas M. LaroncIe, Inc.

Ins ection Method doing our work, we used the following methods:

0 Visual inspection of tubes and deposits as we saw them in place or as they weie presented to us at the plant.

o Videoprobe inspections of tubes in place.

o Visual inspection with a 15X magnifying lens of the interior surfaces, of cooling coils and tubes that had been split longitudinally.

o Microscopic examination of selected cooler coils in the PP&L Hazleton Laboratory.

0 Microbiological cultures of deposits from cooling coils, using media specific for sulfate-reducing and acid-producing bacteria (SRB and APB).

On-site Ins ection Results 2E-217C RHR Oil Cooler Coil This and the other RHR oil cooling coil are type K copper. The 2E-217C cooler had been removed from the system for several days before our inspection, and the specimens we saw were dry. The inner surfaces were covered with a heavy, dense scale. Areas of this scale were colored green, white, and brown, indicating different metallic components in the scale.

We carefully cleaned the deposit from sections of this coil and examined the metal with a 15X hand lens. We found numerous random pits over most of the surface. These pits varied greatly in si.ze, depth, and shape.

Most were irregular in shape, small and shallow, but some were sharp-edged and quite deep.

We took samples of the deposit from pitted areas of this coil and ran biological cultures for SRB and APB as explained above. These cultures showed no response in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. After 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, sufficient growth had occurred to indicate that low to moderate levels of these bacteri.a were present in this coil.

2. 1E-217A RHR Oil Cooler Coil The 2E-217C RHR oil cooler coil carries ESW water from the B 'loop. To obtain a comparison with the A loop, we inspected the 1E-217A coil, using the same methods described above. We inspected sections cut from the second coil layer from the top and the second layer from the bottom.

The nature of the deposit in the 1E-217A coil was entirely different from the 2E-217C coil. We found none of the hard "scale" deposits described in 2E-217C. Instead, we found a loose, flowable black deposit, and below that (next to the metal) a hard, firmly-attached black layer. SEM/EDAX analysis of this deposit at Hazleton identified this black deposit as primarily manganese salts.

Page 2

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Thomas M. Laronge, Inc.

We found pits beneath the black deposit. All were very small, irregular in shape, and randomly distributed. No pits were as deep as those found in 2E-217C.

,. 2E-217B RHR Oil Cooler Coil To provide a second inspection of oil coolers on the B ESW loop, we inspected the 2E-217B coil. This coil was found to be intermediate in condition between the 1E-217A and 2E-217C coils. No hard scale was present. We found substantial black deposits that were later identified by SEM/EDAX as primarily manganese compounds. The black deposit was stringy and covered part but not all of the surface.

Under the deposit in this coil we found pitting that was more prevalent and deeper than in 1E-217A but not as serious as in 2E-217C.

Microbiological cultures of the deposits covering these pits showed less activity than either of the other two RHR oil coolers.

4, OE-507D Diesel Generator Jacket Water Cooler The tubes in this cooler are reported to be 90/10 cupronickel. ET inspection of this exchanger had identified at least one tube with more than 60X wall penetration. We identified this tube -from the "map" in the ET inspection report and were able to visually inspect the entire inside surface using the newly-acquired fiberscope equipment. We were able to .

see many pitted areas in this tube. We could not measure pit depth, but some appeared to be very deep. As in other coolers, the pits were randomly distributed and irregular in shape. 'hese tubes had been cleaned, and we were not able to collect sufficient deposit for microbiological analysis. Tubes should be pulled from this heat exchanger for more detailed inspection.

5. OE-533D Diesel Governor Cooler We examined this very small single tube cooler but were not able to make a detailed inspection. The tube had been cleaned and no deposits were available. We could see what appeared to be minor pitting inside the tube, but no other observations were possible.

6. OE-505E1,2D Diesel Generator Intercooler Inspection of this cooler was difficult. The tubes were too small to permit entrance of the fiberscope. The tube ends (internal) were clean and appeared to show many small pits. No firm conclusion can be drawn; a tube should be pulled from this exchanger for inspection when possible.

7. 1E-228B RCIC Pum Room Unit Cooler This cooler had been open 'for several days before our inspection. The tubes are cupronickel. The tubes had been cleaned, but we found one tube that contained substantial amounts of loose black deposit. We could not use the fiberscope effectively because the tube.

it fit only a short distance into Page 3

Thomas M. LaroncIe, Inc.

The "deposit from this dirty tube showed the highest microbiological activity of any sample tested. 'his sample was one to two orders of magnitude more active than any of the RHR lube oil coolers. We understand t'hat this unit is on the B ESW loop.

One tube from the outside layer was cut out for inspection. By visual (15X) examination, this tube was found to contain numerous under-deposit pits of varying depth and random shape.

8. ESW B Su l Water Line to 1E-228B By disconnecting the flexible hose between the 1E-228B RCIC Pump Room Unit Cooler and the ESW B supply water line, we were able to inspect the interior of the supply water line. Using the fiberscope, we were able to see approximately 18 inches into this line including one 90-degree elbow.

This mild steel line was heavily corroded and covered with a uniform layer of scale. This scale was dark brown in color and varied between 1/16" and about 3/16" in thickness. No outstanding tubercles. were visible. The scale probably is mostly iron oxides.

We removed small pieces of scale from the pipe opening. The underlying metal seemed to be relatively smooth. No serious pitting was seen.

However, viewing was very difficult, and this should not be considered a complete statement of. the condition of this pipe.

This pipe, as we saw it, was typical of mild steel pipe exposed to corrosive water with no chemical treatment for many years. The heavy layers of corrosion-produced scale are probably at this point providing some protection against further general corrosion of the pipe. However, any under-deposit corrosion going on underneath these scale will be very difficult to control without cleaning the pipe.

We ran microbiological cultures on a mixture of deposit and water from this pipe. The cultures responded in less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, indicating very high levels of SRB and APB at this point. The growth rate was similar to tha't found in the sample from 1E-228B.

This was the only piece of mild steel piping or equipment that we inspected during this visit. We believe, however, that the condition of this pipe is similar to that of most of the ESW piping exposed to similar flow conditions.

9. 1E-228A RCIC Pum Room Unit Cooler This unit was opened for inspection in our presence, so that we were able to examine the deposit immediately upon exposure to air. This is important because anaerobic bacteria, typically the SRB and APB of concern at Susquehanna, tend to form spores (become inactive) in the presence of oxygen.

This'nit was cleaner than 1E-228B and contained brown rather than black deposits. Most of the deposits seemed to be in the form of loose, well-flocculated solids with clear water. 1E-228B, by contrast, contained muddy water and slimy, black deposits.

Page 4

Thornos M. Laronge, Inc.

We could not see more than a few inches into the tubes as installed. One tube was cut from the"outside row for our examination. This tube contained less deposit and far fewer pits than the corresponding tube from lE-228B. We understand that 1E-228A receives ESW water from the A loop.

10. 2E-297A ESW GR DX S stem Condenser This exchanger was opened gust before our inspection. We understand that this was the first inspection of this unit. Roughly 75X of the tube sheet was covered with a thick deposit consisting of various colored "scale deposits" plus loose, slimy black material. Most of the tubes were partially or completely blocked with this material. These deposits must restrict flow through this cooler.

The fiberscope would not fit more than a few inches into the tubes. Also, the voluminous deposit made viewing the metal surface impossible. We took a mixed sample of the deposit for microbiological culture analysis. After one day, this sample showed only low level activity.

The 2E-297A cooler was closed, with no cleaning, immediately after our inspection. We recommend that this equipment be cleaned and thoroughly inspected as soon as possible.

Laborator Examination Heat exchanger tubing removed from five ESW coolers was examined in the azleton Laboratory of PP&L. This examination consisted of visual examination th and without a magnifying loupe, visual examination using a 0.7X to 4.5X nitron stereomicroscope and SEM/EDS examination using an Amray 1830 SEM fitted with a Princeton Gamma Technical EDS Analyzer. The latter was operated by Mr. T. J. Pensock and Mr. L. E. Willertz.

.The sections of heat exchanger tubing examined were from the following exchangers:

~Exchac ac Vlacal Stereomicrosco e SEM/EDS 1E-217A X X X 2E-217B X X X 2E-217C X X X 1E-228A X X 1E-228B X X In all cases the RHR pump lube oil coolers examined were removed from the fifth "pancake" or horizontal bank of four loops numbering from the bottom.

Four elbows each from units 2B (fabricated) and from 2C (cast), respectively, were also visually examined. All tubes were sectioned in a horizontal plane so that "top" and "bottom" could be distinguished. Additionally, a section of tubing from 2E-217B was sectioned top-to-bottom so that the horizontal sides could be examined intact.

The RCIC Pump Room Cooler tubes examined were from an outer location i'n the tube bundles. The tubes were split without noting the specific direction of stallation.

Page 5

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Thomas M. Loronc3e, Inc.

Visual inspection clearly showed foreign mat'ter, i.e., scale and deposits on all tube waterside surfaces. Each of the tubes had nearly the same appearance on the waterside except for those from 2E-217C.

he latter tube was essentially covered with a mottled mixture of green, white, and brown deposits, ranging from a few thousandths of an, inch to better than 0.125 inch in thickness. The material appeared to have been laid down in layers. This suggests formation in a series of discontinuances, discrete events such as on-off operating periods, significant water chemistry changes from scaling to non-scaling, and so on.

The e..posed surface was drying out and evidenced cracking at intervals of 0.125 inch to 0.375 inch. This resulted in a rectangular to square patterned peeling appearance.

All other exchanger tubes were covered to varying degrees with a predominantly brown to black, "oily" appearing film. The film was matted with small to large patches of orange-brown to green-brown material which had a dull surface finish. The deposit/scale laid in a distinct pattern on all examined tubes.

Specifically, in the RHR pumps lube oil cooler tubes there was more deposit/scale at the inside diameter than at the outside diameter.

Additionally, there was more material at the bottom of the tubes than at the top of the tubes. Upon cutting these tubes, more deposit/scale spalled from the inside diameter surface than from the outside diameter surface. Where the deposit/scale spalled, a blotchy appearance resulted showing metal surface at ome points. Most of the blotches tended to range in color from a copper olor to an orange-brown color.

Pits were found in all tube specimens examined. Most of the pits were round, although some elongated pits in the direction of flow were seen. No hemispherical pits within pits were seen. Where a single pit appeared to be the composite of two or more individual pits, this appeared to result from horizontal growing together at the corrosion boundaries. In other words, the morphology of small hemispherical pits within pits that is often ascribed to the morphology resulting when MIC occurs was not found. Also, no odor could be detected on freshly cut surfaces. No tunneling or major undercutting was noticed.

Almost all pits were covered with deposit/scale material in the shape of a tubercle except for the pits of 2E-217C. The latter simply had pits beneath the relatively thick deposit.

Several specimens from 1E-217A, 2E-2178, and 2E-217C were mounted for SEM examination. Some of these specimens were vapor coated with carbon to reduce the tendency for surface charging in the SEM. The exact details should be obtained from Messrs. Pensock and/or Willertz as they did the work. We simply witnessed a significant portion, of this on Sunday, June 10, 1990.

While the samples were in the scanning electron microscope, EDS was used on many areas to obtain semiquantitative identification of materials present at examined surfaces. Basically, the electron bombardment of the surfaces esults in the generation of x-rays whose energies are associated with ecific elements. These energies were scanned from about 0 to about 10,000 ectron volts and the quantity of x-rays versus their respective energies Page 6

Thomas M. Laronge, In(:.

h were plotted using computer graphics. The resulting plot or spectrum gives a near exact idea of which materials are present and a qualitative to semi-qualitative idea of how much of each material is present.

All deposit/scale samples examined had, at least, the same basic four elements, namely:

1) Copper.

2) Manganese.

3) Iron.

4) Calcium.

It is believed that the manganese came from either of two sources. These are the influent ESW water and corrosion products of carbon steel or other manganese-containing materials.

It is believed that the iron came from the same two sources listed for manganese. However, some of the iron found could have been the result of iron oxidation by "iron bacteria" to iron (III). 'II)

It is believed that the calcium all came from the ESW influent water. This calcium deposited as the respective solubility products of calcium with certain anions were exceeded. These solubilities are functionally dependent upon time, temperature, pressure, and the amount and type of other materials present.

Suffice it to say, the copper was detected because of the presence of copper in the tubes. Other sources of copper could not be expected to yield detectable amounts in the presence of copper-containing materials.

EDS analysis showed the presence of many other elements. Both chlorine and sulfur were found within pits. Generally, these materials were found together. There was one pit examined in which sulfur was detected and chlorine was not detected, but overall, where these elements were found, chlorine levels were high and sulfur levels were low, relative to each other.

Both chlorine and sulfur-containing compounds are typically implicated in many pitting corrosion processes of copper and copper-bearing alloys. The major difference in implication is that chlorine is involved in generic under-deposit pitting and sulfur is typically involved in MIC pitting.

Mic'robiolo icall -Influenced 'Corrosion (MIC)

MIC refers to a specialized form of under-deposit corrosion in which the metabolic products of bacteria play a significant role in the corrosion process. Typically, SRB and APB generate acid that makes t'e environment under deposits more corrosive to the metal.

It is often assumed that the presence of SRB and/or APB (or other anaerobic bacteria) in a system is proof that MIC is occurring in that system. This is definitely not the case. In order for MXC to be positively confirmed in a system, three conditions must exist:

a. The appropriate bacteria must be present.

Page 7

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Thomas M. Laronge, 1nc.

b. The deposit next to the metal surface must show significantly higher levels of sulfur than would be expected from simple concentration of system water and sulfur-containing general system debris.

c. The morphology of the pits on the metal surface must show patterns known to be characteristic of MIC.

In the Susquehanna plant:

Significant levels of SRB and APB are present. This is not at all surprising since the ESW water is drawn from a pond that supports aquatic plant growth and is known to have anaerobic bottom conditions. This pond receives no chemical treatment other than occasional algacide around the edges as needed.

b. The SEM/EDAX deposit analysis prepared by the Hazleton Laboratory shows high levels of copper and chloride, to be expected in under-deposit corrosion, but only marginally higher levels of sulfur in some cases.

c. The morphology of MIC on most metals consists generally of shallow-walled hemispherical pits, often with smaller "pits within pits." In some cases of MIC> several layers of pits within pits may be observed. On some metals, particularly the austenitic stainless steels, tunneling under the surface may be seen.

These characteristic patterns of pit formation and development were not enerally found during our inspections at Susquehanna. As a rule, the pits ended to be'eparate, randomly oriented and irregular in both size and shape.

We believe that although MIC undoubtedly was a significant factor in some pits and probably aggravated corrosive conditions in other cases, it was neither the major causative factor nor the rate-determining step in the pitting corrosion process.

Under-De osit Pittin Corrosion When deposits are allowed to form on a metal surface exposed to corrosive water, differential concentration cells are created that increase the corrosivity of the water layer beneath the deposit, relative to the bulk water. In effect, a "battery" is formed in which the metal surface below the deposit becomes the anode or active site at which metal dissolves. This results in pitting corrosion.

The degree of pitting that occurs in any given case depends upon many variables, including particularly the metal composition, the water composition, and operating variables. Flow conditions, temperature, and time are the critical operating variables.

The presence of manganese, especially at the high levels found in the Susquehanna ESW deposits, can seriously aggravate pitting corrosion.

Manganese is a multivalent metal. It can exist in several oxidation states and, therefore, encourages electrochemical reactions. This, in effect, increases corrosion rate and particularly pitting corrosion under anganese-containing deposits.

Page 8

Thomo,s M. Lo,ronge, Inc.

Root Cause Summar

'he evidence we have gathered from the work described in this letter leads us o the conclusion that the root cause of the pitting attack observed on copper and cupronickel heat exchanger tubes in the Susquehanna ESW system is conventional under-deposit corrosion aggravated by the high levels of manganese in the deposits.

SRB and APB are clearly present throughout the ESW system, and MIC must be a contributing factor in the pitting corrosion. Some pits may be primarily caused by MIC. However, the chemical analysis and metal surface morphology on all specimens that we examined indicate very strongly that MIC is only a contributing factor and not the root cause of the problem.

We must point out that flow conditions, particularly long periods of no flow, can seriously aggravate pitting corrosion. This may help to explain the heavier deposits and more serious pitting in the 2E-217C RHR oil cooler coil, compared to other parts of the system.

Our complete report, to follow, will include full documentation and discussion of our findings, including appropriate references and background information.

Please contact us with any comments, questions, requests, and/or instructions.

Very truly yours, g~ Arthur J. Freedman Executive Vice President Thomas M. Laronge President CC ~

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