Information Notice 1989-79, Degraded Coatings and Corrosion of Steel Containment Vessels

Degraded Coatings and Corrosion of Steel Containment Vessels

ML031190084
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	12/01/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-079, NUDOCS 8911270001
Download: ML031190084 (8)

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 December 1, 1989 NRC INFORMATION NOTICE NO. 89-79: DEGRADED COATINGS AND CORROSION OF

STEEL CONTAINMENT VESSELS

Addressees

light-water

All holders of operating licenses or construction permits for

reactors.

Purpose

the discovery of

This information notice is intended to alert addresseesiceto condenser contain- severely degraded coatings and the corrosion of steel condensation in the

ment vessels that are caused by boric acid and collected

annular space between the steel shell and the surrounding concrete shield

building. 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 containedno in this information

therefore, specific action or

notice do not constitute NRC requirements;

written response is required.

Description of Circumstances

On August 24, 1989, Duke Power Company reported significant coating damage and

the McGuire

base metal corrosion on the outer surface of the steel shell of leak rate test

Unit 2 containment which was discovered during a pre-integrated Duke

inspection (as required by Appendix J to 10 CFR Part 50). 1 Subsequently, which

Power identified similar degradation of the McGuire Unit containment, is essentially identical to the Unit 2 structure.

freestanding

Both units have ice condenser-type containments consisting of athe shell and

steel shell surrounded by a concrete shield building. Between

steel shells have a -

the shield building is a 6-foot-wide annular space. The degraded on the

nominal thickness near the annulus floor of 1 inch. The sectionsarea no higher

shells of both units is limited to 30-foot circumferential of the corrosion

than 1i inches above the annulus floors. The average depth is up to 0.03 inch

is 0.1 inch with pits of up to 0.125 inch. Corrosion that floor on the Unit 2 deep was also found in areas below the level of-the annulus This below-floor

shell, where concrete was removed to expose the shell surface. the shell and the

corrosion is due to a lack of sealant at the interface between

annulus floor.

8911270001

IN 89-79 December 1, 1989 The probable cause of the degradation is attack by condensed boric acid coolant

leaking from instrument line compression fittings. Drains are provided in the

annulus floor, but they are widely separated and the floor is not sufficiently

graded to prevent pooling of the condensate between the drain locations. The

current average thickness of the corroded areas of the containment shells of

0.9 inch is expected to be reduced to no less than 0.85 inch for Unit 1 and

0.88 inch for Unit 2 by the time they are repaired during the next planned

outages for these units. These estimates were made assuming the worst cor- rosion rates that could reasonably be expected and are greater than the

minimum thickness allowed by the applicable ASME Code.

On September 21, 1989, Duke Power Company discovered coating damage and base

metal corrosion during inspections of the steel shells of its two Catawba con- tainments. These containments are also of the ice condenser type and are very

similar to the McGuire containments; the nominal floor level shell thickness

is 1 inch. Here also, the degradation was located on the outer surfaces of

the shells at the intersection of the shell and the concrete annulus floor.

At Catawba the damage was less extensive and was limited to a circumference

of 15 feet, a height of 1 inch above the annulus floor, and an average depth

of 0.03 inch. The cause is also believed to be attack by boric acid coolant, which had leaked from instrument line compression fittings, condensed, and

collected on the annulus floor.

Duke Power Company plans to repair the steel shells of all four units during

their next respective refueling outages. This will include weld repair and

recoating of the corroded areas.

Discussion:

The degradation of the containment shells at the McGuire and Catawba plants

is considered significant for several reasons. The fact that the corrosion

affects four different units indicates that other steel containments with

similar configurations may be susceptible to the same problem. Furthermore, the observed rate of corrosion far exceeds the allowance made for corrosion

in the containment design. This condition leads to the concern that such

corrosion could result in undetected wall thinning to less than the minimum

design thickness, accompanied by a loss of leaktightness or structural inte- grity. This problem can be prevented by a containment inservice inspection

program that is adequate to ensure early detection and the maintenance of

design margins through proper corrosion control.

The NRC regulations (Appendix J to 10 CFR Part 50) require that a general

visual inspection of the accessible surfaces in the containment be performed

before each integrated leak rate test. The purpose of this inspection is to

identify any evidence of structural deterioration or other problems that may

affect containment integrity or leaktightness. As a result of these and other

inspections, several instances of containment wall thinning due to corrosion

have been discovered during the past 3 years at operating power reactors.

However, the visual inspections done in connection with the integrated leak

IN 89-79 December 1, 1989 rate tests are only required to be performed three times in each 10-year period.

In addition, because of the physical arrangement of plant systems, the steel

surfaces in the annular spaces of some containments may not be easily accessible

to the visual inspections associated with leak tests. Considering the frequency

and severity of recent instances of containment degradation due to corrosion, additional efforts to inspect steel containment surfaces potentially susceptible

to corrosion may be prudent.

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 NRR project manager.

/'6 7A0

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Chen P. Tan, NRR

(301) 492-0829 Keith R. Wichman, NRR

(301) 492-0908 Attachment: -List of Recently Issued NRC Information Notices

Attachment

IN 89-79 D*cUmb4t I 1959 Page I of I

LIST OF RECENTLYISSUED

NOTICES

lRC INFODIATIOII

-. ,ant- UMate T

itcei No. Subject ilssunce lusued to

89-SI. Questionable Certification 11/22/S9 All holders of Ots

Supp. I of material Supplied to or CPa for nuclear

the Defense Department power reactors.

by Nuclear Supplirs

8t-78 Fel lure of Packing NutU 11/22t89 All ItC 11icnsees

n One-Inch Uranium authorized to possess

lexefluoride Cylinder and use source metarial

Valves end/or special nuclear

material for the heating.

ewptying, filling or

shipping of uranium

hexafluoride In 30.

and 48-inch diareter

Cylinders.

89-77 Debris In Contaienwnt 11/21/t89 All holden of OLs

Esergency Sumps end or CPs tor PaRs.

Incorrect Sreenn

Configuretions

t9-7i S1ifouling Agent, Zebra 11/21/t9 All holders of OLs

or CPS for nuclear

power reactors.

89.7S Felsification of Holder 11/20/89 All holders of OLs

Quealifications for or CPa tor nuclear

Coetrector Expleoys power reactors.

t-74 Clerification of Traes- ll7/8 All munufecturern

portsti1e Rqrbments and distributors of

Applicable to Return of radisphormecewticals

Spent Radiopharraq Dosages for sedical une

trom Users to Suppliers nuclear phareacen.

and medical licensees.

It-73 Potential Owverenesrization II/1/St All holders of OLs

of LowPressure SyStaft or Cfa for nuclear

pOer reactors.

89-72 Failure of Licensed Senier 10/24/8t All holders of OLs

Operntors to Classify or CPs for nuclear

Emargeacy Events Properly power reactors.

OL

• Opereting License

CP

• Constrctioe Permit

FIRST CLASS MAIL

UNITED STATES POSTA0IS FEES PAID

NUCLEAR REGULATORY COMMISSION USNRC

WASHINGTON, D.C. 20555 4- PERIr No.Ale

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, *300

t

IN 89-79 December 1, 1989 rate tests are only required to be performed three times in each 10-year period.

In addition, because of the physical arrangement of plant systems, the steel

surfaces in the annular spaces of some containments may not be easily accessible

to the visual inspections associated with leak tests. Considering the frequency

and severity of recent instances of containment degradation due to corrosion, additional efforts to inspect steel containment surfaces potentially susceptible

to corrosion may be prudent.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Chen P. Tan, NRR

(301) 492-0829 Keith R. Wichman, NRR

(301) 492-0908 Attachment: List of Recently Issued NRC Information Notices

Document Name: IN 89-79

• SEE PREVIOUS CONCURRENCES

• EMTB:DET:NRR D/DOEA:NRR% *C/OGCB:DOEA:NRR *RPB:ARM

CYCheng CERossi A CHBerlinger TechEd

11/22/89 11/2W89 11/22/89 11/17/89

• OGCB:DOEA:NRR *EMlTB:DET:NRR *ESGB:DET:NRR *C/ESGB:DET:NRR *D/DET: NRR

DCKirkpatrick KWichman CPTan GBagchi JRichardson

11/15/89 11/22/89 11/21/89 11/21/89 11/22/89

IN 89-XX

November xx, 1989 accessible to the visual Inspections associated with leak tests. Considering

the frequency and severity of recent instances of containment degradation due

to corrosion, additional efforts to inspect steel containment surfaces poten- tially susceptible to corrosion may be prudent.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Chen P. Tan

(301) 492-0829 Keith R. Wichman, NRR

(301) 492-0908 Attachment: List of Recently Issued NRC Information Notices

Document Name: IN CONlrAINMENT CORROSION

• SEE PREYIQV CONCURRENCES

T/, :. 0Pz D/DOEA:NRR C/OGCB:DOEA:NRR *RPB:ARM

CERossi CHBerlinger TechEd

11/ /89 11A918 11/17/89

• OGCB: J0BA 4LRR

DCKirkpatrck KW

i

man

NRR *ESGB:DET:NRR *(C/ESGB:DET:NRR

CPTan Bagchi

D/DET: NRR

JRichardsW

V

11/15/89 11/12!89 11/21/89 L1/21/89 11/Z;U89 M

IN 89-XX

November xx, 1989 the frequency and severity of recent instances of containment degradation due

to corrosion, additional efforts to inspect steel containment surfaces at some

plants may be prudent.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Chen P. Tan

(301) 492-0829 Keith R. Wichman, NRR

(301) 492-0908 Attachment: List of Recently Issued NRC Information Notices

Document Name: IN CONTAINMENT CORROSION

• SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB:DOEA:NRR *RPB:ARM

CERossi CHBerlinger TechEd

11/ /89 11/ /89 11/17/89

• OGCB:DOEA:NRR EMTB:DET:NRR ESGB:DET:NRR C/ESGJ -j~hR D/DET: NRR

DCKirkpatrick KWichman CPTan Aret GBag hi V JRichardson

11/15/89 11/ /89 11/al /89 11/n /89 11/ /89

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instances of containment wall thinning due to corrosion have been discovered

during the past three-years at operating power reactors. However, the visual

inspections done in connection with the integrated leak rate tests are only

required to be performed three times in each a year period. In addition, because of the physical arrangement of plant systems, the steel surfaces in the

annular spaces of some containments may fall outside o the usual scope of the

LLret ted visual inspectionv' Considering the frequency and severity

lektt-i

of recent instances of containment degradation due to corrosion, additional

efforts to inspect steel containment surfaces at some plants may be prudent.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Chen P. Tan

(301) 492-0829 Keith R. Wichman, NRR

(301) 492-0908 Attachment: List of Recently Issued NRC Information Notices

Document Name: IN CONTAINMENT CORROSION

D/DOEA:NRR C/OGCB:DOEA:NRR

CERossi CHBerlinger

11/ /89 11/ /89 OGCB:DOEA:NRR EMTB:DET:NRR ESGB:DET:NRR C/ESGB:DET:NRR RPB:ARM

DCKirkpatrick KWichman CPTan GBagchi TechEdM X

1114AWDe 11/ /89 11/ /89 11/ /89 11//9 /89