Information Notice 1994-42, Cracking in the Lower Region of the Core Shroud in Boiling-Water Reactors

Cracking in the Lower Region of the Core Shroud in Boiling-Water Reactors

ML031070026
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:	06/07/1994
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-94-042, NUDOCS 9406060138
Download: ML031070026 (12)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 June 7, 1994 NRC INFORMATION NOTICE 94-42: CRACKING IN THE LOWER REGION OF THE CORE SHROUD

IN BOILING-WATER REACTORS

Addressees

All holders of operating licenses or construction permits for boiling-water

reactors (BWRs).

Purpose

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

notice to alert addressees that a 360-degree crack has been observed at a weld

in the lower region of the core shroud in two boiling-water reactors. It is

expected that 'ecipients 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

During the April 1994 refueling outage at Dresden Unit 3, Commonwealth Edison

Company, the licensee, found a 360-degree crack that extended around the

outside circumference of the core plate support ring weldment. The shroud is

a 5.1 centimeter [2 inch]-thick stainless steel cylinder that directs the flow

of water inside the reactor pressure vessel. The shroud is completely

contained inside the reactor pressure vessel. The structural integrity of the

reactor pressure vessel is not affected by cracks in the shroud.

The cracking was found during a visual inspection and was located in the lower

section of the shroud in the heat-affected zone (HAZ) of weld H-5. (See

Figures 1 and 2.) Weld H-5 is a horizontal weld that joins the core plate

support ring to the core shroud. Subsequent ultrasonic testing, utilizing

automated equipment from General Electric, determined that the maximum crack

depth was 2.13 cm [0.84 inches].

Commonwealth Edison Company also performed a visual inspection of the

Quad Cities Unit 1 core shroud. That inspection revealed a similar 360-degree

circumferential crack located at the same place as the crack found at Dresden

Unit 3. Both Dresden and Quad Cities units are BWR-3s and have similar core

shroud geometries. Core shroud designs for other BWRs may exhibit some

differences, and weld identification numbers are not necessarily congruent

between the designs.

9406060138- P I

IRAQ <4on/ 673OS/3 t

v-' IN 94-42 June 7, 1994 Discussion

At Dresden Unit 3, in addition to the 360-degree circumferential crack in the

HAZ of weld H-5, numerous crack indications were also found in the HAZ of weld

H-3. The licensee plans to perform UTs and take boat samples at both Dresden

Unit 3 and Quad Cities Unit 1 to help determine the root cause of the

cracking.

Commonwealth Edison Company inspected the Dresden shroud using a criterion

that required the resolution of a 25 micron [1 mil] wire with a 25-mm camera

lens positioned to within 2.5 to 7.6 cm [1 to 3 inches] of the shroud surface.

The same 25 micron [1 mil] wire resolution criterion had been used previously

at Quad Cities, but with a 9 mm camera lens positioned approximately 15.2 to

30.5 cm [6 to 12 inches] from the shroud surface. Using this technique, no

crack indications were initially detected at Quad Cities. However, after

Commonwealth Edison Company detected the crack at Dresden, the H-5 weld at

Quad Cities was inspected again, this time using the Dresden technique, and

the 360-degree crack was detected.

Related Generic Communications

In Information Notice (IN)93-79, "Core Shroud Cracking at Beltline Region

Welds in Boiling-Water Reactors," (issued September 30, 1993) which discusses

cracks detected at Brunswick Unit 1, the staff pointed out that camera and

lighting positions were crucial in performing adequate visual inspections. It

is imperative to position the camera or video probe as near to the examination

surface as possible and to use an appropriate camera lens. The lighting

direction and intensity are important factors and should be adjustable to

enhance the detection of these tight surface crack indications.

Crack indications have been previously reported at shroud welds in domestic

and overseas reactors at the beltline region and higher in the shroud.

However, the severely cracked H-5 shroud welds at Dresden Unit 3 and

Quad Cites Unit 1 are located 45.7 centimeters [18 inches] below the bottom of

the fuel, suggesting that horizontal welds in all regions of the shroud may be

susceptible to stress corrosion cracking

The IN 93-79 also referred to GE Rapid Information Communication Service

Information Letter (RICSIL) No. 054, Revision 1, "Core Support Shroud Crack

Indication." Since IN 93-79 was issued, GE issued additional information on

core shroud cracks in October 1993, April 1994, and May 1994.

The BWR Owner's Group (BWROG) submitted an evaluation of core shroud cracking

to the staff on April 5, 1994. After reviewing the evaluation, and in light

of the Dresden and Quad Cities findings, the staff issued a list of questions

to the Chairman of the BWROG Executive Oversight Committee on May 12, 1994.

The NRC staff is evaluating the safety implications of the shroud cracks for

normal plant operating and accident conditions and will consider the need for

additional generic communication.

IN 94-42 June 7, 1994 This information notice requires no specific action or written response. 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR

(301) 504-2768 J. Schapker, RIII

(708) 829-9715 T. Greene, NRR

(301) 504-1175 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

Attachment 1 IN 94-42 June 7, 1994 Hi

H2 H3 H4

upport Plate

_ H5 H6 H7 Not to Scale

Figure 1. Shroud Weld Locations for Dresden, Unit 3

DRESDEN UNIT-3 CORE SHROUD

DETAIL - WELDS TYPE H5

-- 10--42"

(2 H5 1" FILLET

WELD

_ A...M..

CRACK - -

1" FILLET

H6- WELD

OUTSIDE INSIDE

(

Not to Scale -0 C- - >

to0 et

(D (D to aw

• 11 0

h - D

-. to

4- r'o

Figure 2. Detail of Weld Locations H5 and HO in the Dresden, Unit 3 Core Shroud

i tachment 3 IN 94-42 June 7, 1994 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

94-41 Problems with General 06/07/94 All holders of OLs or CPs

Electric Type CR124 for nuclear power reactors.

Overload Relay Ambient

Compensation

94-40 Failure of a Rod Control 05/26/94 All holders of OLs or CPs

Cluster Assembly to Fully for pressurized-water

Insert Following a Reactor reactors (PWRs).

Trip at Braidwood Unit 2

94-39 Id ntified Problems in 05/31/94 All U.S. Nuclear Regulatory

Gamma Stereotactic Commission Teletherapy

Radiosurgery Medical Licensees.

94-38 Results of a Special NRC 05/27/94 All holders of OLs or CPs

Inspection at Dresden for NPRs and all fuel cycle

Nuclear Power Station and materials licensees

Unit 1 Following a Rupture authorized to possess spent

of Service Water Inside fuel.

Containment

94-37 Misadministration Caused 05/27/94 All U.S. Nuclear Regulatory

by a Bent Interstitial Commission Medical Licensees

Needle during Brachy- authorized to use brachy- therapy Procedure therapy sources in high-,

medium-, and pulsed-dose- rate remote afterloaders.

94-36 Undetected Accumulation 05/24/94 All holders of OLs or CPs

of Gas in Reactor for nuclear power reactors.

Coolant System

91-81, Switchyard Problems that 05/19/94 All holders of OLs or CPs

Supp. 1 Contribute to Loss of for nuclear power reactors.

Offsite Power

OL = Operating License

CP = Construction Permit

IN 94-42 June 7, 1994 This information notice requires no specific action or written response. 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 BKGrimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR

(301) 504-2768 J. Schapker, RIII

(708) 829-9715 T. Greene, NRR

(301) 504-1175 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

• See orevious concurrence

OFC OEAB:DORS lSC/OEAB:DORS PUB:ADM lPDIII-2:ADR3 NAME TGreene* RDennig* Tech Ed* JStang*

DATE 106/03/94 06/03/94 05/17/94 05/19/94 OFC PDIII-2:ADR3 PD/PDIII-2 PDI-1:ADR1 SRXB:DSSA

NAME CPatel* RCapra* DBrinkman* ACubbage*

DATE 05/19/94 05/19/94 105/19/94 05/19/94 OFC SRXB:DSSA AD/DSSA EMCB:DE EMCB:DE

NAME MRubin* MVirgilio* WKoo* RHermann*

DATE 05/19/94 06/03/94 05/18/94 05/18/94 OFC. C/EMCB:DE RI RIII RIII

NAME JStrosnider* JSchapker* MLeach* TMartin*

DATE 05/18/94 05/19/94 06/01/94 ,- ,05/19/94 OFC C/OEAB:DORS AC/OGCB:DORS D _

NAME AChaffee* RKiessel* /e

DATE 06/03/94 06/03/94 06/,('/94 ______*._n_____

LOFFICIAL RECOR ------

---

COPY] di~:~ -'r.f TitIII

[OFFICIAL UMUMtN NAMb: V4-44 .1N

IN 94-XX

May XX, 1994 additional generic communication.

This information notice requires no specific action or written response. 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR

(301) 504-2768 J. Schapker, RIII

(708) 829-9715 T. Greene, NRR

(301) 504-1175 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

• Seea nrevinus concurrence

OFC lf0 SV D ORS PUB:ADM PDIII-2:ADR3 NAME TGreeneI Rt n'nig Tech Ed* JStang*

DATE l / ' /94 K / 3 /94 05/17/94 05/19/94 OFC PDIII-2:ADR3 PD/PDIII-2 PDI-1:ADR1 SRXB:DSSA

NAME CPatel* RCapra* DBrinkman* ACubbage*

DATE 05/19/94 05/19/94 05/19/94 05/19/94 OFC SRXB:DSSA AD/DSSA EMCB:DE EMCB:DE

NAME MRubin* MVirgili

(D / /94 S

fWKoo*

05/18/94 RHermann*

05/18/94 DATE 05/19/94 2 '

OFC C/EMCB:DE RI R_ __t_

__ __RIII

NAME JStrosnider* JSchapker* MLeach TMartin*

T

DATE 05/18/94 05/19/94 of/61 /94 05/19/94 OFC C/OEAB:DORS AC/OGCB:ORS &/DORS

AC :i

NAME

I3

{ BGrmes

DATE /94 _ __ _ _ _ ____

OFFICIAL RECORD COPY] DOCUMENT NAME: G:\TAG \INDRES.SH

K

K-/ IN 94-XX

May XX, 1994 This information notice requires no specific action or written response. 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR J. Schapker, RI

(301) 504-2768 (708) 829-9715 T. Greene, NRR M. Leach, RIII

(301) 504-1175 (708) 829-9603 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

• See previous concurrence

OFC OEAB:DORS SC/OEAB:DORS PUB:ADM PDIII- 6 R3 NAME TGreene RDennig Tech Ed* Jstj z

DATE 5 //8'/94 / /94 05/17/94 14-AA94 OFC PDIII-2:ADR3 PD/PDIII-2 PDI-1:ADR1 SR*B:DSSA

NAME CPatel CM RCapra f"' DBrinkman~ g ACubbage

DATE [r//I /94 5/l I/94 I* / /94 / /94 OFC SRXB:DSSA C/SRXB:DSSA EMCB:DE EMCB:DE

NAME MRubin RJones GHornseth RHermann

DATE / /94 / /94 / /94 / /94 OFC C/EMCB:DE RI RIII C/OEAB:DORS

NAME JStrosnider JSchapker MLeach AChaffee

DATE / /94 / /94 / /94 / /94 OFC AC/OGCB:DORS D/DORS

NAME AKugler BGrimes

DATE / /94 / /94

[OFFICIAL RECORD COPY]

DOCUMENT NAME: P:\INDRES.SH

-

IN 94-XX

May XX, 1994 This information notice requires no specific action or written response. 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR J. Schapker, RI

(301) 504-2768 (708) 829-9715 T. Greene, NRR M. Leach, RIII

(301) 504-1175 (708) 829-9603 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

• Con ny-vouini concuqrrence

OFC OEAB:DORS j SC/OEAB:DORS PUB:ADM PDIII-2:ADR3 NAME TGreene RDennig Tech Ed* JStang

DATE S //'/94 / /94 05/17/94 / /94 OFC PDIII-2:ADR3 PD/PDIII-2 PDI-1:ADR1 SRXB:DSSA

NAME CPatel RCapra DBrinkman ACubbage

DATE / /94 / /94 / /94 / /94 OFC SRXB:DSSA C/SRXB:DSSA EMCB:DE EMCB:DE

NAME MRubin RJones RHerman

DATE / /94 / /94 Y//t/94

5 3./ &d/94 OFC C£MCB:5 RI RIII C/OEAB:DORS

NAME A S ? Mws er JSchapker MLeach AChaffee

DATE '5/jg"/94 / /94 / /94 / /94 OFC AC/OGCB:DORS D/DORS

NAME AKugler BGrimes

DATE / /94 / /94

[OFFICIAL RECORD COPY]

DOCUMENT NAME: P:\INDRES.SH

K.)

OFC OEAB:DORS _ SC/OEAB:DORS PUB:ADM C/OEAB:DORS

NAME TGreene RDennig Tech Ed a Achaffee

DATE / /94 1 / /94 / 17/94 / /94 OFC TECH BRANCH CHF TECH BR C/OGCB:DORS D/DORS

NAME AKugler BGrimes

DATE l / /94 / /94 1 / /94 11//94

[OFFICIAL RECORD COPY]

DOCUMENT NAME:

ADD TO CONCURRENCE:

John Stang PDIII-2 Chandu Patel PDIII-2 Robert Capra PDIII-2 Donald Brinkman PDI-1

Amy Cubbage SRXB

Mark Rubin SRXB

Robert Jones SRXB

Geoffrey Hornseth EMCB

Robert Hermann EMCB

Jack Strosnider EMCB

Jerry Schapker RI

Mel Leach Rgn III

'~ IN 94-XX

May XX, 1994 This information notice requires no specific action or written response. 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: R. Hermann, NRR J. Schapker, RI

(301) 504-2768 (708) 829-9715 T. Greene, NRR M. Leach, RIII

(301) 504-1175 (708) 829-9603 Attachments:

1. Figure 1: Shroud Weld Locations for Dresden Unit 3

2. Figure 2: Details of Weld Locations H-5 and H-6 in the

Dresden Unit 3 Core Shroud

3. List of Recently Issued NRC Information Notices

OFC B:DORS SC/OEAB:DORS PUB:ADM PDIII-2:ADR3 NAME TGreene RDennig Tech Ed JStang

DATE / /94 / /94 / /94 / /94 OFC

NAME

PDIII-2:ADR3 CPatel

PD/PDIII-2 RCapra

JPDI-I:ADR1 J SRXB:DSSA

DBrinkman ACubbage

DAT El / /94 I /94 / /94 I /94 OFC SRXB:DSSA C/SRXB:DSSA EMCB:DE EMCB:DE

NAME MRubin RJones GHornseth RHermann

DATE / /94 / /94 / /94 / /94 OFC C/EMCB:DE RI RIII C/OEAB:DORS

NAME JStrosnider JSchapker MLeach AChaffee

DATE / /94 / /94 / /94 / 94 OFC AC/OGCB:DORS D/DORS

NAME AKugler BGrimes

DATE / /94 / /94

[OFFICIAL RECORD COPY]

DOCUMENT NAME: P:\INDRES.SH