Information Notice 1999-19, Rupture of the Shell Side of a Feedwater Heater at the Point Beach Nuclear Plant

Rupture of the Shell Side of a Feedwater Heater at the Point Beach Nuclear Plant

ML031040409
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, 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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	06/23/1999
From:	Marsh L Division of Regulatory Improvement Programs
To:
References
IN-99-019, NUDOCS 9906180003
Download: ML031040409 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 23, 1999 NRC INFORMATION NOTICE 99-19: RUPTURE OF THE SHELL SIDE OF A FEEDWATER

HEATER AT THE POINT BEACH NUCLEAR PLANT

Addressees

All holders of operating licenses or construction permits for nuclear power reactors.

Puroose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert

addressees to the recent rupture of the shell side of a feedwater heater at the Point Beach

Nuclear Plant. The reactor was manually tripped because of the steam leak that resulted from

the failed heater shell. It is expected that recipients will review the information for applicability

to their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in this information notice are not NRC requirements; therefore, no

specific action or written response is required.

Description of Circumstances

On May 14, 1999, at 7:13 a.m. (CST), Point Beach Unit I was manually tripped from 100-

percent power because of a steam leak from the 4B feedwater heater. The steam leak

resulted when the shell side of the feedwater heater ruptured. Shortly after the reactor trip, reactor operators manually actuated the safety injection system because of a decreasing

pressurizer level. However, no water was injected, and pressurizer level was restored through

normal charging. Plant equipment responded appropriately. No one was injured during this

event because no personnel were in the vicinity of the ruptured heater. The fish-mouth rupture

was approximately 27 inches long and .75 inch at its widest point. The rupture was located

adjacent to the extraction steam pipe inlet.

Discussion

The feedwater heaters at Point Beach are low-pressure, horizontal, shell and U-tube heat

exchangers. Each heater consists of a hemispherical channelhead welded to the tubesheet, which is then welded to the shell. The heater that failed was manufactured by Struthers Wells, Inc., and was installed in 1984. The heater had operated for 97,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />. The channelhead

of the heater contains feedwater inlet and outlet nozzles. Extraction steam enters through the

top of the shell, where it is deflected by a stainless steel diffuser plate directly under the

e ion steam inlet nozzle. The purpose of the diffuser plate is to protect the heater tube

9901800 ?DR t O ciCW42

IN 99-19 June 23, 1999 bundle from the direct impact of the extraction steam. The source of the extraction steam is

the discharge nozzles of the high pressure turbine. The moisture/steam mixture from the high

pressure turbine passes through a preseparator tank and then into the feedwater heater. The

licensee's experience has been that the preseparator tank has not been entirely effective in

removing all moisture from the extraction steam. Therefore, the quality of the extraction steam

entering the feedwater heater has not been optimal.

When the extraction steam enters the feedwater heater it is deflected by the diffuser plate. The

deflected steam impinges on the carbon steel shell of the feedwater heater adjacent to the

extraction steam inlet nozzle. The area of steam impingement is the area where the rupture

occurred. The thickness of the heater wall in the area of the rupture was determined to be as

little as .05 inch (nominal wall thickness is .5 inch). The degraded area extended approximately

4 feet along the length of the feedwater heater. An inspection of the second feedwater heater

in the same stage of feedwater heating found similar shell wall degradation; however, no failure

was experienced.

The licensee cut out the degraded sections of the feedwater heater and replaced them with

0.625- inch carbon steel plate. Following a recommendation from Struthers Wells, the licensee

also removed the six tube bundle guide bars in an attempt to reduce the turbulent flow that may

have contributed to the wall thinning. The licensee sent the sections of heater shell that were

removed to a materials laboratory for analysis. The licensee's root-cause investigation is

continuing. The feedwater heat exchangers at Point Beach Unit 2 were also inspected and no

degradation was found.

The licensee stated that the feedwater heaters were not included in any periodic inspection

program. As part of their corrective actions, the licensee intends to develop an inspection

program for all feedwater heaters at the plant. Similar failures of feedwater heaters had

previously occurred at the Dresden Nuclear Power Station in 1983 and as recently as

January 18, 1999, at the Susquehanna Steam Electric Station and April 28, 1999, at the

Pilgrim Station.

On March 7, 1983, the licensee for Dresden Unit 3 found a steam leak from the shell of the

number 3C3 low-pressure feedwater heater near the extraction steam inlet nozzle. The cause

of the leak was attributed to erosion of the heater shell by deflected extraction steam.

Nine days before a refueling outage, the licensee for the Pilgrim Station found two holes in one

of the low-pressure feedwater heaters at the plant. One of the holes was 0.5 by 1 inch. The

other was approximately 1 inch in diameter. The holes were in the heater wall opposite the 24- inch extraction steam inlet.

Similarly, the Susquehanna licensee observed a steam leak from the shell of the Unit 2, number

3C feedwater heater. The shell-side rupture was approximately 0.5 inch by 1.5 inches and was

located 90 degrees from the extraction steam inlet pipe and slightly above the center line of the

feedwater heater.

IN 99-19 June 23, 1999 The licensees in the above described events did not have in place an inspection program for

examining the thickness of the walls of feedwater heaters. Failures of these and similar

components can result in undesirable challenges to plant safety systems required for safe

shutdown and accident mitigation. Such failures can result in complex challenges to operating

staff. Also, injury to, and death of, personnel can result from failures of high energy

components or piping.

This information notice requires no specific action or written response. However, recipients are

reminded that they are required by 10 CFR 50.65 to take industry-wide operating experience

(including information presented in NRC information notices) into consideration, when practical, when setting goals and performing periodic evaluations. If you have any questions about the

information in this notice, please contact one of the technical contacts listed below or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contact: K. Parczewski, NRR

301-415-2705 E-mail kipDnrc.aov

Nick Fields, NRR

301-415-1173 E-mail enf(&nrc.gov

Attachment: List of Recently Issued NRC Information Notices

_"' Attachment

IN 99-19 June 23, 1999 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

99-18 Update on NRC's Year 2000 6/14/99 All material and fuel cycle

Activities for Materials Licensees and licensees and certificate holders

Fuel Cycle Licensees and Certificate Holders

99-17 Problems Associated with Post-Fire 6/3/99 All holders of OL for nuclear

Safe-Shutdown Circuit Analyses power reactors, except those who

have permanently ceased

operations and have certified that

the fuel has been permanently

removed from the reactor

99-15 Misapplication of 10 CFR Part 71 5/27/99 All holders of operating licenses or

Transportation Shipping Cask construction permits for nuclear

Licensing Basis to 10 CFR Part 50 power reactors

Design Basis

99-14 Unanticipated Reactor Water 5/5/99 All holders of licenses for nuclear

Draindown at Quad Cities Unit 2, power, test, and research reactors

Arkansas Nuclear One Unit 2 and Fitzpatrick

99-13 Insights from NRR Inspections 4/29/99 All holders of operating licenses

of Low-and Medium-Voltage for nuclear power reactors

Circuit Breaker Maintenance

Programs

99-12 Year 2000 Computer Systems 4/28/99 All holders of operating licenses

Readiness Audits or construction permits for nuclear

power plants

99-11 Incidents Involving the Use of 4/23/99 All medical use licensees

Radioactive Iodine-131 OL = Operating License

CP = Construction Permit

IN 99-19 June 23, 1999 The licensees in the above described events did not have in place an inspection program for

examining the thickness of the walls of feedwater heaters. Failures of these and similar

components can result in undesirable challenges to plant safety systems required for safe

shutdown and accident mitigation. Such failures can result in complex challenges to operating

staff. Also, injury to, and death of, personnel can result from failures of high energy

components or piping.

This information notice requires no specific action or written response. However, recipients are

reminded that they are required by 10 CFR 50.65 to take industry-wide operating experience

(including information presented in NRC information notices) into consideration, when practical, when setting goals and performing periodic evaluations. If you have any questions about the

information in this notice, please contact one of the technical contacts listed below or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

[Orig. /s/'d by]

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contact: K. Parczewski, NRR

301-415-2705 E-mail: kxpenrc.gov

Nick Fields, NRR

301-415-1173 E-mail enf(Dnrc.qov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: S:\DRPM_SEC\99-19.in

To receive a copy of this document, indicate in the box C=Copy wlo attachmentlendosure E=Copy with attachment/endosure N = No copy

OFFICE PECB I EMCI I E EMCIZ EMCI I E DD DE l C:PEC3 I

NAME EFields* CLauron* BBateman* Parczewski* RWessman* LMarsh*

DATE [6/08/99 J06/08/99 j 6/09/99 j 06/08/99 j 06/09/99 6/17/99 OFFICIAL RECORD COPY

IN 99-xx

June xx, 1999 The licensees in the above described events did not have in place an inspection program for

examining the thickness of the walls of feedwater heaters. Failures of these and similar

components can result in undesirable challenges to plant safety systems required for safe

shutdown and accident mitigation. Such failures can result in complex challenges to operating

staff. Also, injury to, and death of, personnel can result from failures of high energy

components or piping.

This information notice requires no specific action or written response. However, recipients are

reminded that they are required by 10 CFR 50.65 to take industry-wide operating experience

(including information presented in NRC information notices) into consideration, when practical, when setting goals and performing periodic evaluations. If you have any questions about the

information in this notice, please contact one of the technical contacts listed below or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contact: K. Parczewski, NRR

301-415-2705 E-mail: kxpenrc.gov

Nick Fields, NRR

301-415-1173 E-mail enf(&inrc.qov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: G:\REXB\enf\PTBEACH.IN.wpd

To receive a copy of this document, indicate in the box C=Copy w/o attachmenVenclosure E=Copy with attachment/enclosure N= No copy

OFFICE jPC llEMCI3 lE lEMCI3 I EMCI3 I E lDD:DE I C:PECI3 AV

NAME ENicks CLauron* BBateman* Parczewski* RWessman* LMarsh .1 DATE 6SL99 06/08/99 Le(q'(j 1 06/08199 06/09199 If L/199 OFFICIAL RECORD COPY

-' A' IN 99-xx

June xx, 1999 The licensees in the above described events did not have in place an inspection program for

examining the thickness of the walls of feedwater heaters. Failures of these and similar

components can result in undesirable challenges to plant safety systems required for safe

shutdown and accident mitigation. Such failures can result in complex challenges to operating

staff. Also, injury to and death of personnel can result from failures of high energy components

or piping.

This information notice requires no specific action or written response. However, recipients are

reminded that they are required by 10 CFR 50.65 to take industry-wide operating experience

(including information presented in NRC information notices) into consideration, when practical, when setting goals and performing periodic evaluations. If you have any questions about the

information in this notice, please contact the technical contact listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.

Ledyard B. Marsh, Chief

Events Assessment, Generic Communications

and Non-Power Reactors Branch

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

K. Parczewski, NRR

301-415-2705 E-mail: kxpenrc.gov

Technical contact: Nick Fields, NRR

301-415-1173 E-mail enfhnrc.aov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: G:\REXB\enf\PTBEACH.IN.wpd

To receive a copy of this document, indicate in the box C=copy wo atta entencdosure E=Copy with attachmenVenclosure N = No copy

OFFICE PECB Il EMCB I I; EMCB lC:PECB I

NAME ENicks CLauron 0 0BteMnJJ Parczewskid IMarsh

__s_

DATE I /99 k619906/9I99 ,

_____9199 _ _

_99 OFFICIAL RECORD COPY