ML20235J924

Forwards Summary of Secondary Piping Inspected/Replaced During 1987 Trojan Refueling Outage.Insps Identified Numerous Locations Where Pipe Wall Thinning Occurred in Secondary Piping

ML20235J924
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	07/10/1987
From:	Cockfield D PORTLAND GENERAL ELECTRIC CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
TAC-65727, NUDOCS 8707160061
Download: ML20235J924 (7)

Text

.

m mamma e Portland General ElectricComparry David W. Cockfield Vice President, Nuclear July 10, 1987 Trojan Nuclear plant Docket 50-344 Licenso NPF-1 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555

Dear Sir:

Secondary Piping Erosion / Corrosion During the 1987 refueling outage at Trojan, extensive secondary piping crosion/ corrosion inspections were performed. These inspections have identified numerous locations where pipe wall thinning has occurred in the secondary piping. Under current industry guidance, many of these locations may not have been identified as being likely sites where this phenomenon would occur.

Attachment 1 provides a summary of all piping inspected and all piping replaced or being replaced during the 1987 outage. piping has boon or l is being replaced whenever the measured wall thickness is below minimum allowabic, or is projected to fall below minimum allowabic prior to the 1988 outage.

All safety-related feedwater piping has been inspected. This inspection consisted of ultrasonic thickness measurements of all welds, of the piping at 1 foot intervals, and on 4 inch grids at each elbow. If i indications of pipe wall thinning were observed, the inspections were performed on shorter intervals or smaller grid patterns.

1 61 8707]o f G CK 05000344 '

PDR 1 o

121 S W Sa!n on S! eet, Podard Omgan 97204

- - _ _ _ - - - _ - _ _ _ = - _ _ = _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ - - - - _ _ - _ - _ _ _ _ _ _ - _ . _ _ _ _ _ _ _ _ _ ~

1 Portland General ElectricCcarpsw Document Control Desk July 10, 1987 Page 2 Following completion of the inspection and replacement efforts under our current program, pCE is confident of the integrity of the affected piping systems for the next operating cycle. Continued improvements are planned to the erosion / corrosion monitoring program before the 1988 outage. An overview of the planned enhancements to this program is provided in Attachment 2.

Sincerely, Attachments c: Mr.-John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission Mr. R. C. Barr NRC Resident Inspector Trojan Nuclear Plant Mr. David Kish, Director State of Oregon Department of Energy 1

1

)

)

l l

1 l

1 1

Trojan Nuclear Plant Document Control Desk July 10, 1987 Docket 50-344 License NPF-1 Attachment 1 1

Pago 1 of 4 I

I l

j

SUMMARY

OF SECONDARY PIPING INSPECTED / REPLACED f

DURING THE 1987 YROJAN REFUELING OUTAGE The following tables summarize the secondary piping inspected / replaced during the 1987 refueling outago at the Trojan Nucicar Plant. Table 1 provides details for large boro (> 2-1/2 inches) piping, while Table 2 provides a more general summary of data for small bore (< 2-1/2 inches) piping. Inspections were performed using ultrasonic thickness measurement methods unless otherwise noted as being visual. A visual inspection involved opening the piping and looking for physical evidence of crosion/ corrosion at specific locations.

TABLE 1

(

Large Bore (> 2-1/2 inches) Piping 1 1

System / Location for all Four Loopt Replaced if Appropriate Inspected Main Stean (MS) - Steam Generator 1 tee; 14 - 90* olbows; None.

to Turbino 1 - 45* elbow; 64 foot of piping; 3 - 90* cibows (visual); 90 feet of l

piping (visual) l MS Line to Steam Jet Air' 1 tee; 2 - 90* elbows; None.

Ej ectors 1 reducer; 3 feet of piping.

MS Bypass to Steam Dump 1 - 90* elbow; 1 reducer; None.

6 feet of piping.

l Feedwater (FW) Syntem - No. 6 FW l Heater to Steam Generator j Safety-Related 24 - 90* elbows; 7 - AS* 12 - 90*

elbows; 2 - 30* elbows; cibows; 1 - 45* i 4 reducers; 266 feet elbow; 4 redu-  !

of piping. cors; 125 feet j of piping.  ;

l Trojan Nuclear Plent Document Contro) nopk i Docket 50-344 July 10, 1987 License NpF-1 Attachment 1 Page 2 of 4 .

Inspected ReplacLd l System / Location 9 tees; 31 - 90

• elbows; 1 tee; 4 - 90*

Non-Safety-Related elbows; 4 - 45' 4 - 45* elbows; 2 - 30*

elbows; 8 reducers; elbows; 42 feet 335 feet of piping; of piping.

1 - 90* elbow (visual);

23 feet of piping (visual).

Feedwater (FW) System - No. 3 FW 6 - 90* elbows; 2 - 45' None.

Heater to Main Feed Pump Sue. tion cibows; 4 - 30* cibows; f I

37 feet of piping.

3 tees; 10 - 90* elbows; 2 tees; 2 - 90*

FW System - Main FW Pump Dischstge to No. 6 FW Heater 2 - 60* cibows; I 45* cibows; 2 - 60* ,

elbow; 24 feet of piping. cibows, j FW System - Recirculation Line 4 tees; 11 - 90* elbows; 2 - 90* elbows; l 1 - 75* olbow; I - 45* 2 feet of I olbow; 118 feet of piping. f piping.

Heater Drain System - First and 10 tees; 8 - 90* elbows; None. j Second Stage Reheater Drain Tanks 8 reducers; 16 feet of and Moisture Separator Reheater piping.

Drain Tanks to Heater Drain Tanks (including Nos. 5, 6, and 7 FW Heaters).

Heater Drain System - Heater Dtain

~

1 tee; 3 - 90* elbows; None.

Tank to Condcuser 20 feet of piping.

Heater Drain Pump suction From 1 - 90* elbow; 1 foot None.

Heater Drain Tanks of piping.

2 tees; 5 - 90* elbows; 1 - 90* olbow; Heater Drain Pump Dischary.c to 1 reducer; 2 - 45* el- 2 feet of Main FW Line bovs; 97 feet of piping, piping.

Heater Drain Pump Vent to Heater 2 - 90* elbows. None.

Drain Tanks 2 - 90* elbows; 3 feet None.

Heater Drain Tank Vent to No. 5 FW Heater of piping.

l

Trojan Nuclear Plant Document Control Desk July 10, 1987 Docket 50-344 License NPF-1 Attachment 1 Page 3 of 4 Inspected Replaced System / Location 1 tee; 1 - 90* cibow; None.

Steam Generator Blowdown Down-1 reducer; 2 feet of stream of Steam Generator Blow-down Tank piping.

Approximately 600 feet None.

Moisture Separator Reheater Cross-Under Piping - High-Pressure (visual).

Turbine to Moisture Separator Reheater.

Extraction Steam to First Stage I tee; I - 45' cibow; None.

Moisture Separator Reheater 2 feet of piping.

Steam Seal Regulator Bypass 1 tee; 2 - 90* cibows; None.

2 reducers; 3 feet of piping.

l

Document Control Desk j Trojan Nuclear Plant July 10, 1987 J Docket 50-344 License NPF-1 Attachment 1 Pago 4 of 4 1

TABLE 2 Small Bore (< 2-1/2 inches) Piping i

Inspected Replaced System / Location l

Condensate Receiver Tank Pump 3 feet of piping. None.  !

Discharge Extraction Steam - Steam Traps 30 feet of piping. 8 feet of I 3

piping.

Heater Drain Pump Discharge Vents 12 feet of piping. None.

Feodwater Heaters SA and SB - 24 foot of piping. None.

Vent Lines Feedwater Heaters 6A, 6B, 7A, 184 feet of piping. 80 feet of piping.

and 7B - Vent Lines Main Feed Pump Steam Trap Piping 33 foot of piping. 6 feet of piping. ,

l Moisture Separator Roheater 48 feet of piping. 19 foot of l piping. l Drains l Steam Generator Blowdown Piping - 32 feet of piping. None. )

Containment to Steam Generator Blowdown Tank Main Steam Line Steam Traps 45 feet of piping. 9 foot of piping.

Main Steam Sample Line Steam Traps None. 4 feet of piping replaced due to leak.

Main Steam Bypass - Steam Trap 10 feet of piping. 2 feet of piping.

Piping NOTE: Piping lengths are approximate.

DWC/CAZ/DLN/mr 1484P

A Trojan Nuclear Plant Document Control Desk July 10, 1987 Docket 50-344 License NPF-1 Attachment 2  !

TROJAN SECONDARY PIPING EROSION / CORROSION MONITORING PROGRAM ENHANCEMENTS Trojan secondary pAping crosion/ corrosion inspections will be conducted in f 1988 based upon the experience gained in 1987 and the recommendations provided l 4

by an independent consultant. These inspections will include enhancements in the following areas:

1. More definitive guidance on the selection of piping to be inspected, and I on sample size expansion. Selection parameters to be considered will j include moisture content, water chemistry, fluid velocity, pipe geometry, pipe material, and toteperature.

2. Standardization of ultrasonic testing (UT) measurement and recording techniques to allow year-to-year comparison of data.

l

3. More definitive guidance on the evaluation of data, including computer-ized evaluation of crosion/ corrosion rates, using the Electric Power Research Institute (EPRI) CHEC Program.

A detailed evaluation of 1987 data will be completed to support the selection of piping to inspect in 1988. This evaluation will include:

1. Determining wear allowances on piping components, using baseline data for new replacetaent fittings and pipe sections.

2. Selecting a sample of the replacement components to examine in 1988 to 1 establish crosion/ corrosion rates.

3. Selecting a sample of components not replaced in 1987 to reexamine in 1988 to establish actual erosion / corrosion rates.

4. Calculating erosion / corrosion rates, using the EPRI CHEC Program, and calculating remaining time to reach minimum wall thickness. Any compo-nent with a calculated remaining time of less than two years will be reexamined in 1988.

A data base will be established to allow trending of erosion / corrosion data.

Simplified isometric drawings will be generated on the Computer Aided Drafting System. Each fitting, pipe section, and weld will be uniquely identified.

All components and previous data will be input into the EPRI CHEC Program.

l l

l DWC/GAZ/DLN/mr 1484P