Information Notice 1987-36, Significant Unexpected Erosion of Feedwater Lines

Significant Unexpected Erosion of Feedwater Lines

ML031130521
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	08/04/1987
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-87-036, NUDOCS 8707290264
Download: ML031130521 (8)

SSINS No.: 6835 IN 87-36 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555 August 4, 1987 NRC INFORMATION NOTICE NO. 87-36: SIGNIFICANT UNEXPECTED EROSION OF

FEEDVATER LINES

Addressees

All nuclear power reactor facilities holding an operating license or a con- struction permit.

Purpose

This information notice is provided to alert recipients to a potentially

generic problem pertaining to significant unexpected erosion which resulted

in pipe wall thinning in the safety-related portions of feedwater lines and

other related problems. It is expected that recipients will review the Infor- mation for applicability to their facilities and consider actions, if appro- priate, to preclude a similar problem. However, suggestions contained in this

notice do not constitute NRC redpuirements; therefore no specific action or

written response is required.

Description of Circumstances

At the Trojan Nuclear Plant it was discovered that at least two areas of the

straight sections of the main feedwater piping system experienced wall thinning

to an extent that the pipe wall thickness would have reached the minimum thick- ness required by the design code (ANSI B31.7, "Nuclear Power Piping") during

the next refueling cycle. These areas are in safety-related portions of ASME

Boiler and Pressure Vessel Code (ASME Code) Class 2 piping inside containment.

The pipe wall had thinned in both horizontal and vertical runs that were at

least seven pipe diameters downstream of elbows or other devices that can cause

flow turbulence. Criteria developed by the Electric Power Research Institute

(EPRI Users Manual NSAC-112, "CHEC [Chexal-Horowitz-Erosion-CorrosionJ,I dated

June 1987) would not have required that the pipe wall in these straight sec- tions be examined.

Although the straight sections of eroded 14-inch pipe were slightly thicker

than the minimum required thickness, it was projected that the pipe wall

thickness would erode below the minimum required thickness before the next

major outage. Consequently, the licensee plans to replace this piping before

restart.

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8707290264 Ul

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IN 87-36 August 4, 1987 The Trojan plant is conducting a failure analysis on the degraded components to

determine the causes and mechanisms involved in the observed wall thinning

event. The NRC is evaluating the data available to determine any generic

implication of the event.

Related Generic Communications:

IE Information Notice 82-22, "Failure in Turbine Exhaust Lines," dated July 9,

1982 provides additional information pertaining to erosion/corrosion in wet

steam piping. Other erosion/corrosion events pertaining specifically to the

feedwater systems (including emergency and auxiliary feedwater) have occurred

in feedwater pump minimum-flow lines, J-tubes in steam generator feedwater

rings, and emergency feedwater supply to a helium circulator.

IE Information Notice 86-106, "Feedwater Line Break," was issued December 16,

1986. It described the then-known details of the December 9,, 1986 failure of

the suction line to a main feedwater pump at Surry Power Station Unit 2.

Supplement 1 to this information notice, which was issued February 13, 1987, provided additional detail on the failure mechanism. Supplement 2, which was

issued on March 10, 1987, discussed the effects of the system interactions that

resulted from the line break.

NRC Bulletin 87-01, "Thinning of Pipe Wall in Nuclear Power Plants," issued on

Juty-9;-987, requested that iTcensees submit information concernffng-thirlf

programs for monitoring the thickness of pipe walls in high-energy single-phase

and two-phase carbon steel piping systems.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

rle

E.RostDirector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Paul C. Wu, NRR

(301) 492-8987 Attachment: List of Recently Issued NPC Information Notices

IN 87-36 August 4, 1987 The licensee believes that the high flow velocity of 22.6 ft/sec, in combina- tion with other operating factors, may be the cause of the thinning.

This thinning was discovered when the steam piping inspection program at the

Trojan plant was expanded to include single-phase piping. Trojan personnel

inspected essentially all safety-related high energy carbon steel piping

inside containment.

In addition, the licensee discovered approximately 30 additional areas of the

main feedwater piping system where the pipe wall had thinned so the thickness

of the pipe wall was either less than the minimum thickness required by the

design code or would have eroded to the minimum required thickness during the

next operating cycle. Of these areas, 10 were in the safety-related portions

of the system, while the rest were in non-safety-related portions. All of

these thirty additional areas were in regions that the EPRI criteria would have

indicated as 'needing examination.

Discussion:

The feedwater system inside containment consists of four lines. Lines A and B

are mirror images, as are Lines C and D. The parameters of the ASME Code Class

2 portion of the piping system are as listed below.

Design Temperature ^ 4450 F

Operating Temperature 4450F

Design Pressure 1125 psi

Operating Pressure 920 psi

Piping Material A-106 GRB

Diameter 14-in. OD

Wall Thickness Nominal 0.593 in.

Wall Thickness Minimal (ANSI B31.7) 0.510 in.

Oxygen Content 4 ppb

pH 9.0

Flow Velocity 22.6 ft/sec @ 100% power

The thinning of the straight sections occurred in Lines A and D.

A number of 45- and 90-degree elbows and two 60-degree elbows were also replaced.

The thickness of the remaining pipe wall in these areas ranged from 0.43 to

0.46 in. The minimum required thickness is 0.499 in., and nominal wall thick- ness at time of installation was 0.593 ir

In the non-safety-related portions of the feedwater lines, a total of 20 pieces

of 14-in. pipe were replaced. This total included elbows as well as some

straight pieces down stream of the elbows or other discontinuities. The

thinning in these segments is very similar to that in the ASME Code Class 2 portion except that the minimum required thickness was 0.44 in.

Trojan personnel also replaced a segment of 30-in. header pipe after identify- ing a localized portion of header pipe that had eroded to 1.018-in. wall.

thickness (a minimum thickness of 1.63 in. was required).

\' Attachment

IN 87-36 August 4, 1987 LIST OF RECENTLY ISSUED

INFORMATION NOTICES 1987 InTornation Dare or

Notice No. Subject Issuance Issued to

87-35 Reactor Trip Breaker, 7/30/87 All nuclear power

Westinghouse Model DS-416, reactor facilities

Failed to Open on Manual holding an OL or

Initiation from the Cortrol CP employing W DS-J'6 PooP reactor trip 6reakers.

87-34 Single Failures inAuxIliary 7/24/87 All holders of an

Feedwater Systems OL or a CP for

pressurized water

reactor facilities.

87-33 Applicability of 10 CFR 7/24/87 All NRC licensees.

Part 21 to Nonlicensees

87-3? Deficiencies In the Testing 7/10/87 All nuclear power

of Nuclear-Grade kctivated reactor facilities

Charcoal. holding an OL or CP.

87-31 8locking. Bracing, and 7/10/87 All NRC licensees.

Securing of Radioactive

Materials Packages in

Transportation.

87-30 Cracking of Surge Ring 7/2/87 All nuclear power

Brackets in Large General reactor facilities

Electric Company Electric holding an AL or CP.

Motors.

87-29 Recent Safety-Related 6/26/87 All NRClicensees

Incidents at Larqe authorized to possess

Irradiators. and use sealed sources

in large irradiators.

87-28 Air Systems Problems at 6/27/87 All nuclear power

U.S. Light Water Reactors. reactor facilities

holding an OL or CP.

OL u Operating License

CP * Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION FlRST CLASS MAIL

POSTAGE

• FEES PAID

WASHINGTON, D.C. 20555 USNRC

WASH. D.C.

PERMIT No. a4j

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

IN 87-36 August 4, 1987 The Trojan plant is conducting a failure analysis on the degraded components to

determine the causes and mechanisms involved in the observed wall thinning

event. The NRC is evaluating the data available to determine any generic

implication of the event.

Related Generic Communications:

IE Information Notice 82-22, "Failure in Turbine Exhaust Lines," dated July 9,

1982 provides additional information pertaining to erosion/corrosion in wet

steam piping. Other erosion/corrosion events pertaining specifically to the

feedwater systems (including emergency and auxiliary feedwater) have occurred

in feedwater pump minimum-flow lines, J-tubes in steam generator feedwater

rings, and emergency feedwater supply to a helium circulator.

FE Info mation Notice 86-106, "Feedwater Line Break," was issued December 16,

1986. It described the then-known details of the December 9, 1986 failure of

the suction line to a main feedwater pump at Surry Power Station Unit 2.

Supplement 1 to this information notice, which was issued February 13, 1987, provided additional detail on the failure mechanism. Supplement 2, which was

issued on March 10, 1987, discussed the effects of the system interactions that

resulted from the line break.

NRC Bulletin 87-01, "Thinning of Pipe Wall in Nuclear Power Plants," issued on

July 9, 1987, requested that licensees submit information concerning their

programs for monitoring the thickness of pipe walls in high-energy single-phase

and two-phase carbon steel piping systems.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Paul C. Wu, NRR

(301) 492-8987 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

• C/OGCB:DOEA:NRR *PPMB:ARM

CHBerlinger TechEd

07p4 87 07/28/87 07/28/87

• OGCB.DOEA:NRR *ECE :DEST:NRR *AC/ECEB:DEST:NRR *EAD:DEST:NRR

RJKiessel PCWu CEMcCracken JRichardson

07/16/87 07/16/87 07/16/87 07/16/87

IN 87-XX

July xx, 1987 The Trojan plant is conducting a failure analysis on the degraded components to

determine the causes and mechanisms involved in the observed wall thinning

event. The NRC is evaluating the data available and has formed a task force to

determine any generic implication of the event.

Related Generic Communications:

IE Information Notice 82-22, "Failure in Turbine Exhaust Lines," dated July 9,

1982 provides additional information pertaining to erosion/corrosion in wet

steam piping. Other erosion/corrosion events pertaining specifically to the

feedwater systems (including emergency and auxiliary feedwater) have occurred

in feedwater pump minimum-flow lines, J-tubes in steam generator feedwater

rings, and emergency feedwater supply to a helium circulator.

IE Information Notice 86-106, "Feedwater Line Break," was issued December 16,

1986. It described the then-known details of the December 9, 1986 failure of

the suction line to the main feedwater pump at Surry Power Station Unit 2.

Supplement 1 to this information notice, which was issued February 13, 1987, provided additional detail on the failure mechanism. Supplement 2, which was

issued on March 10, 1987, discussed the effects of the system interactions that

resulted from the line break.

NRC Bulletin 87-01, "Thinning of Pipe Wall in Nuclear Power Plants," issued on

July 9, 1987, requested that licensees submit information concerning their

programs for monitoring the thickness of pipe walls in high-energy single-phase

and two-phase carbon steel piping systems.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

Charles E. Rossi, Director

Division of Operational Event Assessment

Office of Nuclear Reactor Regulation

Paul C. Wu, NRR

(301) 492-8987 Attachment: List of Recently Issued IE Information Notices

• SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB:DOEAiNRR *PPMB:ARM

CERossi CHBerling ' if TechEd

07/ /87 07/~t/87 07/28/87

• OGCB:DOEA:NRR *ECEB:DEST:NRR *AC/ECEB:DEST:NRR *EAD:DEST:NRR

RJKiessel PCWu CEMcCracken JRichardson

07/16/87 07/16/87 07/16/87 07/16/87

IN 87-XX

July xx, 1987 The Trojan Power Station is conducting a failure analysis on the degraded

components to determine the causes and mechanisms involved in the observed wall

thinning event. The NRC is evaluating the data available and has formed a task

force to determine any generic implication of the event.

Related Generic Communications:

TE Information Notice 82-22, "Failure in Turbine Exhaust Lines," dated July 9,

1982 provides additional information pertaining to erosion/corrosion in wet

steam piping. Other erosion/corrosion events pertaining specifically to the

feedwater systems (including emergency and auxiliary feedwater) have occurred

in feedwater pump minimum flow lines, J-tubes in steam generator feedwater

rings, and emergency feedwater supply to a helium circulator.

Information Notice 86-106, "Feedwater Line Break," was issued December 16,

1986. It described the, then known, details of the December 9, 1986, failure

of the suction line to the main feedwater pump at Surry Power Station Unit 2.

Supplement 1 to this information notice, which was issued February 13, 1987, provided additional detail on the failure mechanism. Supplement 2, which was

issued on March 10, 1987, discussed the effects of the system interactions

which resulted from the line break.

NRC Bulletin 87-01, "Thinning of Pipe Wall in Nuclear Power Plants," issued on

July 9, 1987, requested that licensees submit information concerning their

programs for monitoring the thickness of pipe walls in high-energy single-phase

and two-phase carbon steel piping systems.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

Charles E. Rossi, Director

Division of Operational Event Assessment

Office of Nuclear Reactor Regulation

Paul C. Wu, NRR

(301) 492-8987 Attachment: List of Recently Issued IE Information Notices

• SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB:DOEA:NRR PPMB:ARJ4 CERossi CHBerlinger TechEd '

07/ /87 07/ /87 07/1V/87

• OGCB:DOEA:NRR *ECEB:DEST:NRR *AC/ECEB:DEST:NRR *EAD:DEST:NRR

RJKiessel PCWu CEMcCracken JRichardson

07/16/87 07/16/87 07/16/87 07/16/87

. . P

IN 87-XX

July xx, 1987 Related Generic Communications:

IE Information Notice 82-22, "Failure in Turbine Exhaust Lines," dated July 9,

1982 provides additional information pertaining to erosion/corrosion in wet

steam piping. Other erosion/corrosion events pertaining specifically to the

feedwater systems (including emergency and auxiliary feedwater) have occurred

in feedwater pump minimum flow lines, J-tubes in steam generator feedwater

rings, and emergency feedwater supply to a helium circulator.

Information Notice 86-106, "Feedwater Line Break," was issued December 16,

1986. It described the, then known, details of the December 9, 1986, failure

of the suction line to the main feedwater pump at Surry Power Station Unit 2.

Supplement 1 to this information notice, which was issued February 13, 1987, provided additional detail on the failure mechanism. Supplement 2, which was

issued on March 10, 1987, discussed the effects of the system interactions

which resulted from the line break.

NRC Bulletin 87-01, "Thinning of Pipe Wall in Nuclear Power Plants," issued on

July 9, 1987, requested that licensees submit information concerning their

programs for monitoring the thickness of pipe walls in high-energy single-phase

and two-phase carbon steel piping systems.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

Charles E. Rossi, Director

Division of Operational Event Assessment

Office of Nuclear Reactor Regulation

Paul C. Wu, NRR

(301) 492-8987 Attachment: List of Recently Issued IE Information Notices

D/DOEA:NRR C/OGCB:DOEA:NRR PPMB:A

CERossi CHBerlinger TechEd bsf/

07/ /87 07/ /87 07/0(/8 OGCB:DOEA:NRR ECEB: :NRR AC/ECEB:DEST}NR EAD:DESTJIR

RJKiessel PCWu FA<4 CEMcCracke ¢("L__ JRichard on

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