TXX-6705, Responds to NRC Bulletin 87-001, Thinning of Pipe Walls in Nuclear Power Plants. Programs for Establishing Insp Points & Analyzing & Trending Results Will Be Proceduralized & Approved Prior to Unit 1 Fuel Load.Summary Encl

Responds to NRC Bulletin 87-001, Thinning of Pipe Walls in Nuclear Power Plants. Programs for Establishing Insp Points & Analyzing & Trending Results Will Be Proceduralized & Approved Prior to Unit 1 Fuel Load.Summary Encl

ML20238D698
Person / Time
Site:	Comanche Peak
Issue date:	09/08/1987
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
IEB-87-001, IEB-87-1, IEIN-86-106, IEIN-87-036, IEIN-87-36, TXX-6705, NUDOCS 8709110339
Download: ML20238D698 (12)

Text

y i

4 t,

b a

M "llllllll' """

Log # TXX-6705 Fi1e # 10119

(

F E

NRCD 87-01 l

1ERELECTRIC William G. Coumil emot,vc va crea"'

September 8, 1987 1

U. S. Nuclear Regulatory Commission l

Attn: Document Control Desk Washington, D. C.

20555

SUBJECT:

COMANCHE PEAK. STEAM ELECTRIC STATION (CPSES)

DOCKET NOS, 50-445 AND 50-446 i

NRC BULLETIN 87-01 1

THINNING OF PIPE WALLS IN NUCLEAR POWER PLANTS REF:

(1)

'NRC BULLETIN 87-01: THINNING 0F PIPE WALLS IN NUCLEAR l

POWER PLANTS, DATED JULY 9, 1987.

(2)

IE INFORMATION NOTICE NO.86-106, SUPPLEMENT 2:

FEEDWATER L

LINE BREAK, DATED MARCH 18, 1987.

(3)

NRC INFORMATION NOTICE N0. 87-36: SIGNIFICANT UNEXPECTED EROSION OF FEEDWATER LINES, DATED AUGUST 4, 1987.

1 (4)

EPRI REPORT NP-3944:

EROSION / CORROSION IN NUCLEAR PLANT l~

STEAM PIPING - CAUSES AND INSPECTION PROGRAM GUIDELINE, i

DATED APRIL 1985.

(5)

INP0 SIGNIFICANT OPERATING EXPERIENCE REPORT NO. 87-3:

PIPE FAILURES IN HIGH-ENERGY SYSTEMS DUE TO EROSION / CORROSION, DATED MARCH 20, 1987.

L (6)

VEPC0 REPORT: SURRY UNIT 2 REACTOR TRIP AND FEEDWATER PIPE FAILURE REPORT, REVISION 1, DATED MARCH 27, 1987.

Gentlemen:

Reference (1), requires a response from all licensees to submit information concerning a program for monitoring the thickness of pipe walls in high-energy single-phase and two-phase carbon steel piping systems.

L The following information is given in response to NRC Bulletin 87-01,

" Thinning of Pipe Walls in Nuclear Power Plants":

8709110339 870900 J

PDR ADOCM 05000445' j

G PDR n too wris a:ive since La es vanas, renas n:or L

t

k' p

1 i

o TXX-6705-September-8, 1987 L,

Page 2 of 5

- Item 1

- Identify the codes.or standards to which the piping was designed and fabricated.-

CPSES Response All power piping at CPSES was designed and fabricated to either the ASME-B &.PV Code,Section III.-(1974) or ANSI B31.1 (1973).

Specific plant systems

.and codes / standards are identified in the attached Tables 1 and 2.

Item 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:

1

a. ' Selecting points at which to make thickness measurements b.

Determining how frequently to make thickness measurements

- c.

Selecting the methods used to make thickness measurements d.

Making replacement / repair decisions CPSES Response l

a.

CPSES is reviewing all plant systems for areas potentially susceptible to failure by Erosion / Corrosion (E/C) in response to IEN-86-106 (Ref. No. 2).

This effort will result in a wall thickness monitoring program which will establish a baseline in the identified susceptible areas and require reinspection at appropriate intervals following plant startup.

A screening process performed by the Engineering Department identified eleven systems containing carbon steel piping lines with steam and/or liquid phase flow (oils and gases excluded) with an operating temperature greater than 1950F which were potentially susceptible to E/C.

Condensate CVC & Boron Thermal Regeneration (2 lines)

Extraction Steam 4

feedwater Turbine. Gland Steam & Drain Heater Drains Main Steam Process Sampling Auxiliary Steam S/G Blowdown & Cleanup Vent and Drains i

h TXX-6705 September 8, 1987 Page 3 of 5 Target inspection areas in the single-phase systems are being chosen by two methods: the NUMARC/EPRI Chexal-Horowitz-Erosion-Corrosion (CHEC)

(single-phase E/C) computer program and by the methodology suggested in INP0 Significant Operating Experience Report (S0ER) 87-3 (Ref. No. 5) and outlined in the Virgina Electric and Power Company (VEPC0) Report (Ref. No. 6). We plan to follow NUMARC's recommendations and utilize CHEC to determine ten of the inspection sites in the Feedwater/ Condensate systems. We also recognize that recently obtained inspection data from the Trojan Nuclear Station (NRC IN 87-36 (Ref. No. 3)) indicated that CHEC predictions may have been unreliable. Our preliminary inspection points may be reassigned if unreliability is confirmed or our initial data appears to require changing those points.

Single-phase systems ev:11uations will be completed before starting two-phase and mixed systens.

Inspection sites for two-phase systems will be I

determined by methodt recommended in EPRI Report NP-3944 (Ref. No. 4).

b.

Initially the inspection program will be scheduled on a frequency corresponding to refueling outages. However, the program wil.1 be dynamic in that sampling frequency will be governed by results from previous inspections, as well as calculated E/C potentials.

c.

Manual grid-type inspection with digital ultrasonic thickness gage with automatic data recording equipment will be used for the examination.

Inspection personnel will be certified to SNT-TC-1A criteria and procedures will be reviewed by a certified Level III inspector.

Data will be analyzed by a computer for actual wear rates, remaining wall thickness and predicted life, d.

Baseline and subsequent inspection data will be trended to determine the i

point at which the prespecified minimum wall thickness could be achieved.

J i

System design modifications and repair / replacement decisions such as changes to piping configuration or changes in materials will be conservative. The minimum acceptable wall thickness to be used for inspection purposes will be equal to or more conservative than that required by the code. Changes will be implemented at or before minimum wall thickness is achieved.

j l

Item 3

]

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

I l

-_--_____-__A

TXX-6705 September 8, 1987 Page 4 of 5 i

a.

Piping material (e.g., chromium content) b.

Piping configuration (e.g., fittings less than 10 pipe diameters apart) c.

Ph of water in the system (e.g., ph less than 10) d.

System temperature (e.g., between 190 and 500 degrees F) e.

Fluid bulk velocity (e.g., greater than 10 ft/s) f.

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

CPSES Resoonse a.

Yes. Carbon steel (primarily Type SA106, Grade B). The chromium content of carbon steel piping material will be considered, b.

Yes. Tees, elbows, valves (esp. control valves), reducers / expanders, instrument taps, welds in straight pipe.

Primary areas of concern are configurations in which two or more changes of flow direction occur within less than 10 pipe diameters.

c.

Yes. Generally, ph equal to or less than 9.3.

d.

Yes. Greater than 195 degrees F.

e.

Yes. Greater than 5 ft/sec.

f.

No.

Variation of system oxygen content has not been a factor in our inspection program; the eleven systems identified in response 2.a. are each expected to contain less than 10 ppb dissolved oxygen.

Item 4 i

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.

a.

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

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 inspection).

j c.

Report thickness measurement results and note those that were identified as unacceptable and why, d.

Describe actions already taken or planned for piping that 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.

y

+

s TXX-670'5'.

September 8,.1987 Page 5 of.5

'CPSES Response!

Inspections-to identify pipe wall thinning due to velocity-related attack have not yet been performed on.the high energy systems mentioned above. However,

~

~

pipe wall thinning'has been discovered in the. Service Water System (a moderate

< energy system)..Significant Deficiency Analysis Report (SDAR) CP-86-07,

describes a deficiency involving weld failure and coating degradation.in the

. system.

Details of the inspection methods, locations, measurement results and actions;taken.are outlined in Table 3, and Figures 1 and 2.

Our. ongoing and planned corrective actions regarding SDAR CP-86-07 are identified in the following letters to the USNRC:

TXX-6566, dated July 15, 1987, TXX-6348, dated March 26,- 1987, TXX-6251, dated January 30, 1987, TXX-5026,--dated September 19, 1986, TXX-4943,- dated July 30, 1986, TXX-4762, dated April 11, 1986, and'.

TXX-4711,-dated February 24, 1986

. Item 5-Describe any plans either for revising the present or for developing new or-additional programs for monitoring pipe wall thickness.

-CPSES Response The' programs for establishing inspection points, inspecting the identified locations, analyzing.and trending results will'be proceduralized and approved prior to Unit 1. fuel load.

The' applicable corrective action (s) identified by

.the inspection and analysis activities will be performed in accordance with approved procedures..The program will be revised as necessary throughout the

inspection-process.

Baseline data should be available by the end of the first

. refueling.

Very Truly Yours

/

'W. G. Counsil DAR/gj Attachment c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)

t 1

TXX-6705 September 8, "37 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of Texas Utilities Electric Company (Comanche Peak Steam Electric

)

Station, Units 1 & 2)

)

AFFIDAVIT W. G. Counsil being duly sworn, hereby deposes and says that he is Executive Vice President, Nuclear Engineering and Operations of TV Electric, the Applicant herein; that he is duly authorized to sign and file with the Nuclear Regulatory Commission this response to NRC Bulletin 87-01 that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

ATMW W. G. Counsil Executive Vice President, Nuclear Engineering and Operations STATE OF TEXAS

)

)

COUNTY OF DALLAS

)

Subscribed and sworn to before me, a Notary Public in and for Aaru A.4, v

, on this #r4 day of 3.1 16 m / w, 1987.

/

t s x a.J sv $ AMJ Notary Public My commission expires: 3ft 2 fc/ o

sf 7

p

~

~~~- - ~ ~ ~-- ~

T~

s e_

v'TXX-0/b5) i iSep,tember 8, 19877 TABLE 'l PIPE CLASSIFICATION AND' CODE

SUMMARY

p V

PIPE D'ESIGN &

LOCATION ANS' SAFETY ASME

'CLASSIEl-FAB 0F SEISMIC.

CLASSIFI-CODE

CATION /5

- CODE 3 EQUIPMENT CATEGORY

. CATION -

CLASS '

Z I

4

- 2 ASME CONTAINMENT, I_

2 2, MC B&PV SAFEGUARD CODE-BLDG.,.

SECTION III AUXILIARY SUBSECTION NC,NE BLDG, 3

~ASME CONTAINMENT, 1

3 3

B&PV

. SAFEGUARD.

CODE BLDG.,

'SECTION III AUXILIARY

. SUBSECTION ND BLDG.,

i FUEL-BLDG.

- 5 ANSI CONTAINMENT, II/NA NNS B31.1-SAFEGUARD BLOG.,

-AUXILIARY BLDG.,

J FUEL BLDG.

G ANSI.

TURBINE NA NHS l

B31.1 BLDG.,

OUTD0 ORS NOTES:

1.

Refer to ANSI N18.2.

1 2Property "ANSI code" (as page type) with input value "ANSI N18.2.</br></br>1 2" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process..

. Safety classification assigned in accordance with criteria of j

ASME B & PV Code,Section III (Class 1, 2 or 3) and ANSI B31.1 i

(Class 5 or G).

I 3.

Complete identi.fication of: the referenced documents:

{

l ASME.B&PV Code Section III: ASME Boiler and Pressure Vessel Code,Section III, Division 1 Nuclear Power Plant Components, 1974 edition including Summer 74 addendum.

Later code versions, including code cases, have been used optionally.in i

accordance with ASME Code implementation requirements.

ANSI B31.1: AfiSI Standard Code for Pressure Piping, " Power.

Piping", 1973 Edition.

Later Standard versions may be used

[

optionally.

i 4.-

There are some cases where exce)tions are indicated on I

Engineer's isometric drawings t1at ANS class does not correspond to an ASME-Class.

3 S.

Class 1 piping is not within the scope of this NRC Bulletin.

---

m

.______-a_

.E

r.

' TXX-6705-F

'Sep.tember 8, 1987 TABLE 2 CPSES' systems containing high-energy carbon steel piping (excluding gas and oil lines).

PIPE CLASSIFICATION

• SYSTEM 5,G Condensate 5'

CVC & Boron Thermal Regeneration G

Extraction Steam 2.5,G Feedwater G

Turbine Gland Steam & Drain G

Heater Drains 2,3,5,G Main Steam 5-Process Sampling 5,G Auxiliary Steam 5,G SG Blewdown & Cleanup 3,5,G Vents'& Drains i

\\

l

• Pipe Classification for carbon steel piping only. Applicable governing codes given in Table 1.

S aeeiP s

s N

iccwT a

a O

raa I

el l Be e

e T

t pp p

m m

C aeery a

a A

MRrGT S

S

~-

S D

S EM E

n RU N

i I

M K

UI LC 8

QNLI 2

EI AH 3

RMWT SE I

t D

ge s

E a

nd re M

.N r

ds ws.

T e

ii oe E

R SE A

a

()

D SM

.ee:

2 EES dnrt eng N

NRT ei i pi ne A

KUL n. tsi i r CSU n 2 s o p5 d u

.S i 4 rp 1 ag I AS N

HEE h1 o pf 2 ei A

A O

TMR T

woo rF N

N

.I T

T td td C

nl e

nl e E

- ee yv eep P

3.

m rd w ll 3rd wi S

l a 3ai.. ea

- ai -

.p' N

0 ee e

- l ct nt v 0l ct -

I 3

5 er v

0inaia -

5i nao 1

tt l

5mi' if 1 t s i t

ssda) 1i

1d o

- i E

4 nev1

- so6. e o6e 3 s. t 8 g L

S B

E 0

nwl 1

t8gmm 0

2) nma 0) n A

S

0) oot y D

Bbdtl g 0An3ii e

- An3a T

P E

1 r. ofi o1 t r

o1l 1 'n i C

GN

- nagrrF 1 ni - cet f

NI W i c n h e 'e

- i t0el s Wit 0 T

I M PA r"-

itt Waa1 nzn Saa1kd Sa A

p t e Src nzw

- rc cl I X 4T4if us

- Tonooo 4T onee PE 2(2 p o b(

1(l ocnd 2(l N

- onw G

I N

N Y

L I

LOL H

LTA T

A WS CD S

L I EEE L

FDRN A

I NUK W

CESC ETAI N E

PNEH/

P SIMTY Y

A A

I P

N N

M A

n n

R o

o G

i i

O t

t R

)

c c

P L

ek ek A

pa pa N

M se se O

R nl nl I

O i

i T

F e

e C

N l l l l 7

E I

ao ao 8

P

(

uh uh 9

S sn sn 1

N T

ii ii I

U V p V p 8

r 5 e 6

5 5

0b 8

8 8

7 m 6e 3

6 0

- t E

1 0

1 Xp T

Xe A

0 2

9 TS D

1 1

0

~

l!

l

3 2

0 W

S 3

I 0

E 5

V d

1 L

l A

e 4

V W

0 0

F n

O o

1 i

Y t

W T

n a

S I

o r

N i

t 4

I t

e 2

C 5

n I

c e

V o

P L

E l

H e

l 1

T u

l e

o F

W E

N l

H 0

R]

I z

l 1

z n

F G

B o

i I

N P

F N

e I

A n

l R

i Ho T

1 P,

.K l

E l

d T

a l

A m

W e

W W

u E

r t

C h

t I

t T

u V

3 t

B R

2 u

Y E

0 B

M_

S

\\_

W O

S T

I E

e G

v A

l M

a A

V D

[

7 8

9 1

e 8

r 5 e 0b 7 m 6 e

- t X p X e TS i

L C

B N

I

]

AR

(\\

?

T 5

R E

3' TAW f

=

\\

E C

I V

R E

h S

.t

_ n.

N

)

F 0

t i

l 3

o 2

t 0

4 5

1 h

1 t

u 4

a o

0 ae S

2 0

er W

d rA O

m E

1 l

A L

o R

e t

F r

U W

W d s F

G S

ee I

r nn g

F 4

o nn n

2 d

i i i

n hh k

E e

TT o

N(

o N

V L

I L

w N

e O

i V

S x

T o

L

" r 0 p U

[

1 p S

- A E

R T

+

S E

T 2

o o

2 C

0 I

N W

o o O

S S

I AR T

L U

f t

o es me e

an.

d ss nn i n ii 7

sinh 8

ait5 9

et 1

1 t nsh2 i oat scei 8

o rwg poa n

r ps ni 5 e Ol d oe 0b aeib 7 m nt 6 e eenaa

- t t pi ce X p oih or X e N ptl a TS

,i

_,,.-7_,.

• e N

@4 4

C.3 lW

.m m.

'2 W

M.

1 J

i k

t I

I I

1 l

9 a

i

- _ _ _ _ _ _ _ _ _ _. _ _ _ - - - _ - - - - -