ML20234D474

Preventive Maint Procedure PMP 9.7-3, Secondary Side Piping Erosion/Corrosion Measurement

ML20234D474
Person / Time
Site:	Haddam Neck, 05000000
Issue date:	05/07/1986
From:	CONNECTICUT YANKEE ATOMIC POWER CO.
To:
Shared Package
ML20234D443	List: A06665, Forwards Response to NRC Bulletin 87-001, Thinning of Pipe Walls in Nuclear Power Plants. Util Intends to Meet NUMARC Guidelines on Pipe Wall Thinning in high-energy Piping Sys ML20234D464 ML20234D474 ML20234D487 ML20234D504 ML20234D512
References
PMP-9.7-3, NUDOCS 8709220102
Download: ML20234D474 (19)

Text

. .

.-r, 111M1 V i iUQU l P OPER ATIONS REVihh COMMirTEE APP ROV AL Connecticut Yankee C- O s -

,1

' h * 'W Preventive Maintenance Procedure -

i=

i No. PMP 9.7-3 J

- O). 4 l Engineering MA- -U4m/ i

. d-I SECONDARY SIDE PIPING EPOSION/ [/ , [

CORFOSION MEASUREMENT APPROVED BY , AT p yRINTENDENT c e -Jm. .

, l E F F E CTIV E D)AT 1.0 _ OBJECTIVE

4. ~ 7 ' 7 [ ]

The objective of this procedure is to provide instructions for evaluating i secondary side system piping integrity degraded by the effects of erosion /

corrosion.

2.0 LICENSE OR ADMINISTRATIVE REQUIREMENTS l

\

k l None. l I

3.0 REFERENCES

t

! 3.1 Stone 6 k'ebster Pipe Specifications for Connecticut Yankee. {

1 3.2 Inservice Inspection Secondary Side Wall Thickness Program.

3.3 Nortec Instruction Manual for l'1trasonic Digital Thickness gage, j l

3.4 ASME Section III, Beiler and Pressure Ve'ssel Code, 1974 for Class-1 j Piping. -- -

_. j 3.5 ANSI E3:.1 - 1?f3 Editier. Ccde for Power Pipinc. j

\

l 3.6 ANSI B36.19 - 1980 Edition. n

. . . . . .  ; j g l 3.7 ANSI B31G-1984~ Edition Manull f61 T eter-'ining de Remaitrinti-Et ength I

~ ~

of Corrodc:d Pipelines. -- ------l-.- ___ ;

3 .,,f, EPRI Report NP-3944 Erosion / Corrosion 1n NucTear Frafu Etea;. 7 ping:

Causes and Inspu tion Prggram Guidelines. - - - . -

~. -

4. 0 PREP.E0l'ISITES -

~~~f.1 Equipment - the Nortec Mod-el NDT-124D ultrasanic dibilaL.r. hic.kre.ss ..

- page or the equivalent shc11 be 'used te perf crm the; cxamina:Lon.

~ ~

"4.2 Wepn': ation - ripe insulation shall be removed ' and 'pit ng i cNennd when

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l 8709220102 870911 Pace 1 of 12 j--

PDR ADOCK 05000213 -

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- 5.0 PRECAUTIONS id#.Y 0 7 193 S i

J 5.1 The use of this procedure shall be litited to the fo lowing ]

conditions 1

1) corrosion on weldable pipeline steels categorized as carbon _ f steels (eg. 453, A106, A381) l l

ii) defects in the body of the pipe caused by electrolytic or galvanic corrosion.  ;

iii) not to be used to evaluate the remaining strength of corroded welds and related heat affected zones, or defects caused by mechanical damage, or defects introduced during manufacture.

iv) not to be used when piping is subject to significant secondar,v stresses related to pipe line loadings.

5.3 While performing the examination, personnel should be awere of pipe I surface temperatures to avoid burns.

5.4 Personnel shall maintain safe working conditions.

5.3 Ensure that the proper couplant is used for the examination.

6.0 PROCEDURE 6.1 Operation of Model NDT-124D ultrasonic thickness gage 6.1.1 Se]ect transducer mode EHT 5 MHZ and connect to BNC's on l 124D front panel. l l i 6.1.2 Select the'frecuency switch to the 5 MHz position. I NOTE: The 5 MHZ position is used for most applications.

l The 2.25 KHZ is used for rough or cast materials and plastic.

j 6.1.3 Set Enclish/ Metric readout to English readout. English j resdout is in inches; Metric is in centimeters.

NOTE: It is recommended that if the instrument is to be operated in the English mode, it be calibrated in English, and if it is to be used in Metric, it be i calibrated in the Metric mode to eliminate any cumulative error.

6.1.4 Switch ON/0FF/ TEST switch to test position and note battery voltage. A full charge will be over 12.6V. Low batteries l will read 10.5-11V. If no reading is obtained, battery voltage is below instrument cut-off vo)tage and batteries vi13 have to be charged before use, or use online power.

Charge time is approximate]" li hours.

Page 2 of 12

ta,i oa 4s00 6 .2 Calibration-(NOTE: All procedures w131 he the same~fn Fetric) .

6.2.1 Turn instrument "O5" using the OM/OTF /~~J~ twitch.

6.2.2 Use the included stee)' thickness standard or accurate

- standards made from the material to be tested.

6.2.3 Place a small amount of ultrasonic couplant on the standard.

6.2.4 Push the transducer face into the couplant en the .200" step i and firmly hold the transducer in this position.

6.2.5 If necessary, adjust the zero control to read .200.

6.2.6 Remove the transducer from the .200 step and check'the .500 step. If it reads .500, place transducer on the .300" and

.400" steps and check them. If they read within .003", the instrument is calibrated and ready for use.

6.2.7 If the .500 step does not read correctly, adjust the cal.

control to get .500. Then go back to.the .200" step and readjust the zero. Repeat this unti) both steps read correctly.

6.2.8 Then check the .300 and 400 steps and the unit is ready for use.

l 6.2.9 The accuracy of the readings is dependent upon the couplant ,

thickness and smoothness of the part. A Ifghter couplant l should be used on smooch surfaces for accuracy. On rough I corroded surfaces, a thicker coup 3 ant is necessary. ,

6.2.10 There is no need to manua13v switch ranges on the NDT-124D;  ;

l it is done automatically. Calibration shou 3d be performed ,

i on the range to be used for best accuracy, 6.2.11 When the transducer is not in contact with the sample or the i coupling is not adeouste, it will read 1.

l 6.2.12 Accuracy of thickness readings is dependent upon the i velocity of sound in the material. Densitv variations and !I other inhomogeneities may reduce the eccuracy by affectine the velocity by as much as 2 - 5%.

6.3 Examination )

i 6.3.1 Examine area for cleanliness, debris, insulation or other i obstructions which could affect the examination. Have the )

area prepared as necessary. ]

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Page 3 of I?  !

1

- - - _ - - _ _ _ - - - - -__j

~

mm c

• is pv n - socc 6.3.2 place en cmount cf ccuplant compcund on the area to 1.- bef :y 7, cy--freg, c-g---y -.r e - g-ne in ;wne. 27,,,

m05 . EbbCipc R t .C c: LLC Lu rt Lepingement.

InCSE CrCai typically include the outer radius of elbows, backsides of - ==

"T" fittings, and areas immediately downstream of throttling devices (e.g. LCV, orifice, traps).

6.3.3 Scan the aree, taking note of the lowest readings and record those points on the data sheet (Attachmert III).

no 6.3.4 On the data sheet sketch the area examined (i.e., elbow, pipe tee, flange or valve body) and label th.e area where the lowest reading was recorded.

NOTE: Se sure that a reference is given to the orientation of the drawing.

6.3.5 Clean the area of couplant before leaving.

l 6.3.6 Repeat steps 6.3.1 through 6.3.5 on all areas to be examined.

6.4 Evaluation 6.4.1 The ISI Coordinator shall determine the design minimum pipe wall thickness by using Attachment I. This value is calculated utilizing the equation for pipe wall thickness ,

l from ASME Section III KD-3641.1. l l

6.4.2 Compare the design minimum wall thickness calculated above with the data sheers (Attachment III). If the minimum wall thickness measured is less than 90" of the desien wall thickness, then go to step 6.4.3. Otherwise the measured thickness is acceptable.

6.4.3 When the lowest measurement is less than 90" of design thickness, that low spot will need to be reinspected. An evaluation of the maximum longitudinal extent of the corroded area should be determined.

6.4.4 Record the manimum longitudinal) extent of the corroded area on the same data sheet (Attachment III) from ist inspection.

l l

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page 4 of 12 ,

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_ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___ __ _ _ a

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ntu u f. . . .dI d o a 6.4.5 Determine the ripe size (N?F) and nominal pipe wall ]

t' '

hr.cc: fr;- ?ite hier! !. {

6.4.6 Turn to the table in Attachment IV. corresponding to the size p (NPS) of the pipe.

6.4.7 Locate the row showing a depth equal to the measured maximum pit depth (t - t measured). If the exact measured value is not listed, choose.the row showing the NEXT GREATER DEPTH.

gl 6.4.8 Scan across to the column showing the specified wall H thickness of the pipe. If the wall thickness is not listed, use the column for the NEXT THINNER WALL. The value found at the intersection of the wall thickness column and pit depth row is the maximum value permissible for the longitudinal extent of the corroded area (L). l l

l 6.4.9 If the corroded area length exceeds the allewable, the item should be recommended for replacement. If the length does l not exceed the allowable, the item should be inc]uded in the ,

1 next outages inspection base.

7.0 CHECK 0FF 7.1 The checkoff sheet will be provided by the ISI Coordinator. See Attachment II. l l

7.2 The checkoff sheet will identify areas to be inspected by giving the l

following information:  ;

1 A. System involved.

E. ISI-CY number (item).

NOTE: Drawings will be provided by ISI Coordinator to locate pipe area to be inspected.

7.3 The checkoff sheet will include minimum required wall thickness and ,

calculated wall thickness for each area examined.

7.4 The checkoff sheet will include signature signoff.

8.0 ACCEPTANCE CRITERIA 8.1 The ISI Coordinator or designee will determine desien minimum pipe wall thickness by using Attachment I.

Page 5 of 12

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9.1 7ect ca:a snc!; be reecrced. er ca:a sheet ( A :: a :.~.r e r. t III),

10.0 INSPECTION PLAN I.

N/A ,

11.0 FOOTNOTES  :

N/A

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ISI Engineer Date:

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ISI Senior Engineer Page 8 of 12 l

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d,in 0.250 0.312 0.375 0.438 0.469 0.500 0.562 0.625 0.030 11 ..... ..... ..... ... ... . .... ....

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0.060 SW 9% 13 % 14% 15 15 % 16 % .....

0 070 4 6b 10'N 14% 15 15%. 16 % 17%

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0.090 2'b 46 6% 9% 11 % 14 16 % 17%

0.100 2% 3%' 5% 7% 8 "A. 10% 15'i. 17%

0.110 2% 3% 4% 6% 7% 8% 11 % 16"s.

0.120 2w 3% 4% 5% 6% - 7% 9% 12%

0.130 2 2'% 3% 4'N 5% 6% 8W 10%

0.140 1'N 2% 3% db' SN 5 "A. 7% 9%

0.150 1 "sa 2% 3% 4% 4% 5% 6% 8%

0.160 1% 2% 3- 3'% 4% 4% 5% 7%  ;

0.170 1% 2% 2'N 3% 4 4N 5b 6%

0.180 1% 2 2% 3% 3% 4% 5% 6%

0.190 1% 1% 2% 3% 3% 3% - 4% 5 "A.

0.200 1% 1% 2% 3 3b 3'% 4% 5%

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0.440 ..... ..... ..... ..... 1%

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0.450 ..... ... . .... ..... ..... ..... ..... 2%

CL460 ..... ..... ..... ..... ..... ..... ..... 2%

__ 0.470 ..... ..... ..... ..... ..... ..... ..... 2%

0.460 .... ..... .... .... ..... ..... ..... 2W .

IL490 . ..... ..... ..... ..... ..... .. .. ..... 2 S.500 ..... ..... ..... ..... ..... ..... ..... I'%

0.510 ..... ..... ..... ..... ..... ..... .... .....

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Summary of Pipe Replacements Ibsultiry from Pipirn Inspections Based on this data, Connecticut Yankee replaced all of these locations, with the same material called out in our pipiry specifications.

1984 ISO Pipe Si7e/ Class System Min Cale Min Meas.

SK-20-F 6"-WSD-301 M.S. Reheater-A-Drain Line .113" .124 SK-20-G 6"-WSD-301 " " " "

.113" .165 l SK-20-H 6"-WSD-301 " " "

.113" .164 l SK-21-C 6"-WSD-301 M.S. Pcheater-B-Drain Line .113 .055 SX-22-B 6"-WSD-301 M.S. Reheater-C-Drain Line .113 .110 SK-22-D 6"-WSD-301 " ,

.113 .141 l SK-22-C 6"-WSD-301 " " "

.113 .111 SK-22-F 6"-WSD-301 .113 .104 i SK-22-G 6"-WSD-301 " " "

.113 .126 )

SK-22-H 6"-WSL -301 " "

.113 .133 I SK-22-I 6"-WSD-301 " " " "

.113 .130 l l

1986 SK-3-38 10"-SIE-301 1st Ibint Extrrction Stm. Lines .304 .124 d SK-3-39 10"-SIE-301 " " " " "

.304 .240 SK-5-35 12"-SIE-301 " " "

.304 .250 SK-5-35A 12"-SIE-301 " " "

.304 .232 SK-9-20F 16"-S 2E-301 2nd Ibint Extraction Stm. Lines .184 Visual SK-9-20 16 "-S 2E-301 " " " " "

.199 Visual SK-9-20C 16"-S 2E-301 " " " " "

.184 Visual SK-23-F 6"-WSD-301 M.S. Reheater-D-Drain Line .113 .082 3 SX-24-37 14"-SIE-301 1st Ibint Extraction Stm. Lines .304 Visual i SK-24-37A 14"-SIE-301 " " " " "

.304 Visual SK-24-378 1,4 "-S IE-301 " " " " "

.304 Visual I SK-24-37C 14"-SIE-301 " " " " "

.304 Visual  !

SK-24-37E 14 "-SIE-301 .304 .243 SK-25-A 18"-S2E-301 2nd Ibint Extraction Stm. Lines .199 Visual SK-25-G 18 "-S 2E-301 " " " " "

.199 Visual SK-25-C 18"-S2E-301 " " " " "

.199 Visual SK-29-48 6i-WRD-601 "

.277 .200 SK-29-48A 6b-WRRD-601 "

.277 .245 i

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s 1987 ISO Pipe Size / Class System Min Cale Min Meas.

SK-2-6A 18"-SUP-601 Main Steam Line to H.P. Turbine .640 .553 SK-5-19 14 "-SIE-301 1st Ibint Extraction Stm. Lines .320 .310 SK-5-19A 14: 'SIE-301 " " " " "

.303 .1~4 0 SK-5-19B 14 "-SIE-301 "

.303 .190 SK-5-36A 12"-SIE-301 1st Ebint Extraction Stm. Lines .282 .280 SK-12-26E 6"-WFPR-601 Main Feed Pump Pacire. Line .363 .320 SK-12-26F 6"4fPR-601 " " " " "

.363 .330 SK-24-37D 14 "-SIE-301 1st Ibint Extraction Stm. Lines .304 .290 l SK-29-45 6"-WRRD-601 M.S.R. Drain Tk. to F.W. Htts. .276 .170 l SK-29-458 6"-WRRD-601 "

.276 .090 I SK-29-46 6"-WRRD-601 MSR. Drain Tk. to FW Htr. .2.76 .270  !

SK-29-47 6"-WRRD-601 " " " "

.276 .180 SK-30-P 6"4PPR-601 Main Feed Punp Recire. Line .363 .367 f

l SK-30-0 6"-WFPR-601 .363 .366 l

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1 l-Docket'No.-50-245 A06665 Att achment 2 Response to NRC Bulletin 87-01 I Millstone Nuclear Power Station, Unit No. 1 l

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l September 1987-L_________._---_____ _ -

NRC ACTIONS /OUESTIONS

1. Identify the' codes or standards to which the piping was designed and f abricated.

NNECO Response :

All piping at Millstone Station, Unit No. I was designed and.

f abricated to the criteria of ANSI B31.1 - 1967 edition.

1

2. Describe the scope ?and extent of your programs for ensuring that pipe wall thicknesses are not reduced below the minimum allowable thickness. Include in the description the criteria that you have established for:

a. selecting points at which to make thickness measurements

b. determining how f requently to make thickness measurements

c. selecting the methods used to make thickness measurements

d. making replacement / repair decisions NNECO Response:

A secondary plant inspection program for single phase and high energy piping systems was implemented during the 1987 refueling outage. The program is described by Engineering l

Depa r tme n t Instruction 1-ENG-6. 09 issued on July 6, 1987:

Balance of Plant Piping Inservice ' Inspection Prog ram. The instruction is included for your information.

The initial selection was based upon use of a wear prediction model funded by NNECO at_the Massachusetts Institute of Technolog y (MIT ) . The program was used since the EPRI-program was not available at the time. The program considers all of the relevant variables contributing to the erosion-corrosion phenomena. To apply t.he computer program, all plant systems were reviewed for geometry and process conditions. These data were forwarded from the plant to NUSCO engineering for analysis. After the analysis, a walkdown of susceptible areas was made by a systems engineer l and a discipline engineer from which the susceptible i geometries were identified. In accordance with procedure I

l-ENG-6.U9 all areas were then ranked for personnel safety and plant availability. Initially, the NUMARC population of fif teen points was selected although the program was expanded to seventy-two locations as resources were available to dedicate to the effort.

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Page 2 The f requency for determining how of ten to make thickness measurements is left as an engineering judgement. In most areas which were predicted "high wear" areas by the model, negligible wear was detected. In no case was minimum wall thickness projected over the next cycle. Results which predicted time to reach minimum wall thickness in less than ten years were reviewed more closely for determination of inspection interval.

In selection of inspection. methods to be used to make.

thickness measuren.ents ultrasonic test and internal inspection are preferred. The use of methods are specified.

in 1-ENG-6.09. During implementation, the practice has been and will continue to use a qualified Level I, II or III inspector for ultrasonic measurements. Procedures:are in conformance with company approved U.T. practices. The thickness results are reviewed by an engineer.

Repair / replacement decisions are the basis of the acceptance criteria specified in procedure 1-ENG-6.09..These criteria were in accordance with the draft NUMARC criteria available  ;

at the time.  !

l 3. For liquid phase systems, state specifically whether the following f actors have been considered in establishing your criteria for selecting points at which to monitor piping thickness (Item 2a):

a. piping material ( e .g . , chromium content)

b. piping configuration ( e .g . , fittings less than 10 pipe I

diameters apart)

c. pH of water in the system ( e .g . , pH less than 10)

d. system temperature ( e .g . , between 190 and 500 F)

e. fluid bulk velocity (e.g . , g reater than 10 ft/s)

f. oxygen content in the system (e .g . , oxygen content less than 50 ppb)

NNECO Response:

All of the factors specified in the bulletin were considered in the selection of inspection locations.

4. Chronologically list and summarize the results of all inspections that have been performed, which were specifically conducted for the purpose of identifying pipe wall thinning ,

whether or not pipe wall thinning was discovered, and any other inspections where pipe wall thinning was discovered even though that was not the purpose of that inspection.

l a. Briefly describe the inspection program and indicate l whether it was specifically intended to measure wall thickness or whether wall thickness measurements were an incidental determination.

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b. Describe what piping was examined and how (e.g., describe the inspection instrument (s), test method,' reference thickness, locations examined, means for locating measurement point (s) in subsequent inspections),

c. Report thickness measurement results and note those that I were identified as unacceptable and.why.

d. Describe actions already taken or planned for piping that. I has been found to have a nonconforming wall thickness.

If you have performed a failure analysis, include the results of that analysis. Indicate whether the' actions involve repair or replacement, including any change of materials.

NNECO Response:

Prior to the 1987 Ref ueling Outage, Millstone Station, Unit No. I did not have a formalized program for balance of plant-piping. Piping in two phase systems was recognized as a potential problem area. Inspections were as follows:  ;

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a. Main steam line piping inspections up to the turbine stop j valves and by-pass valves, are covered under the ISI j Class I and Class II program. )

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b. As a result of inspections performed in 1980 for two-phase flow piping (extraction steam) a comprehensive replacement program was put in place for piping in the 3

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8th, 9th and lith stage extraction steam. This program was informal and inspections were performed based on EPRI recommendations, plant maintenance records and industry reports. At present, we have replaced all of the 8th and i 9th stage extraction steam piping , and approximately 80% '

of the lith stage extraction steam piping . Completion of the lith stage is scheduled for the next refuel outage.

We have used 3%-5% Chromium-Moly pipi ng for the new piping as recommended by EPRI.

The current program, defined by 1-ENG-6.09 was written to address the issue of wall thinning in single phase systems.

The piping examined under the 1987 ref ueling outage program included feedwater and heater drain. (As indicated above, an extensive replacement program with corrosion resistant piping was undertaken with respect to the extraction steam system.)

Limited sections of feedwater, heater and auxiliary steam piping were the only areas predicted as susceptible to the erosion-corrosion phenomena. Contracted inspectors were used to perform the ultrasonic inspections. Grid methods were used for a majority of locations although " quick scan"- was also utilized. The means for locating the measurement points as well as subsequent inspections is detailed above.

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Thickness'results'for the inspection were all satisfactory.

with respect-to replacement criteria. Some areas will be rescheduled for inspection next outage. .There'were no

" nonconforming" wall thicknesses identified.

5. Describe any plans either for revising the present or for i developing new or additional programs for monitoring pipe I

wall thickness.

NNECO Response:

In a letter dated June 10, 1987,II) NNECO. indicated that we are an active participant in the NUMARC Working Group on .

Piping Erosion / Control . In'an effort to be consistent with.

the industry and maintain consistency within our organi-zation, NNECO intends to meet the- guidelines established by this group for Millstone Unit No. 1.

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1 (1) E. J. Mroczka Letter to U.S. Nuclear Regulatory Commission,

" Piping Inspection Prog rams to Detect Erosion / Corrosion Wear," dated June 10, 1987.

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