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)

4-I 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

All holders of operating

licenses or construction

permits for light-water

reactors.

Purpose

This information

notice is intended to alert addressees

to the discovery

of severely degraded coatings and the corrosion

of steel ice condenser

contain-ment vessels that are caused by boric acid and collected

condensation

in the 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

contained

in this information

notice do not constitute

NRC requirements;

therefore, no specific action or written response is required.Description

of Circumstances:

On August 24, 1989, Duke Power Company reported significant

coating damage and base metal corrosion

on the outer surface of the steel shell of the McGuire Unit 2 containment

which was discovered

during a pre-integrated

leak rate test inspection (as required by Appendix J to 10 CFR Part 50). Subsequently, Duke Power identified

similar degradation

of the McGuire Unit 1 containment, which is essentially

identical

to the Unit 2 structure.

Both units have ice condenser-type

containments

consisting

of a freestanding

steel shell surrounded

by a concrete shield building.

Between the shell and the shield building is a 6-foot-wide

annular space. The steel shells have a -nominal thickness

near the annulus floor of 1 inch. The degraded area on the shells of both units is limited to 30-foot circumferential

sections no higher than 1i inches above the annulus floors. The average depth of the corrosion is 0.1 inch with pits of up to 0.125 inch. Corrosion

that is up to 0.03 inch deep was also found in areas below the level of-the annulus floor on the Unit 2 shell, where concrete was removed to expose the shell surface. This below-floor

corrosion

is due to a lack of sealant at the interface

between the shell and the 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 RECENTLY ISSUED lRC INFODIATIOII

NOTICES-.,ant- Mate U T itcei No. Subject ilssunce 89-SI. Questionable

Certification

11/22/S9 Supp. I of material Supplied to the Defense Department

by Nuclear Supplirs 8t-78 Fel lure of Packing NutU 11/22t89 n One-Inch Uranium lexefluoride

Cylinder Valves 89-77 Debris In Contaienwnt

11/21/t89 Esergency

Sumps end Incorrect

Sreenn Configuretions

t9-7i S1ifouling

Agent, Zebra 11/21/t9 89.7S Felsification

of Holder 11/20/89 Quealifications

for Coetrector

Expleoys t-74 Clerification

of Traes- ll7/8 portsti1e

Rqrbments Applicable

to Return of Spent Radiopharraq

Dosages trom Users to Suppliers It-73 Potential

Owverenesrization

II/1/St of Low Pressure SyStaft lusued to All holders of Ots or CPa for nuclear power reactors.All ItC 11icnsees authorized

to possess and use source metarial end/or special nuclear material for the heating.ewptying, filling or shipping of uranium hexafluoride

In 30.and 48-inch diareter Cylinders.

All holden of OLs or CPs tor PaRs.All holders of OLs or CPS for nuclear power reactors.All holders of OLs or CPa tor nuclear power reactors.All munufecturern

and distributors

of radisphormecewticals

for sedical une nuclear phareacen.

and medical licensees.

All holders of OLs or Cfa for nuclear pOer reactors.All holders of OLs or CPs for nuclear power reactors.89-72 Failure of Licensed Senier Operntors

to Classify Emargeacy

Events Properly 10/24/8t OL

• Opereting

License CP

• Constrctioe

Permit UNITED STATES NUCLEAR REGULATORY

COMMISSION

WASHINGTON, D.C. 20555 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, *300 FIRST CLASS MAIL POSTA0IS FEES PAID USNRC PERIr No.Ale 4- 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

CYCheng 11/22/89*OGCB:DOEA:NRR

DCKirkpatrick

11/15/89*EMlTB:DET:NRR

KWichman 11/22/89 D/DOEA:NRR%

CERossi A 11/2W89*ESGB:DET:NRR

CPTan 11/21/89*C/OGCB:DOEA:NRR

CHBerlinger

11/22/89*C/ESGB:DET:NRR

GBagchi 11/21/89*RPB:ARM TechEd 11/17/89*D/DET: NRR JRichardson

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 CONl*SEE PREYIQV CONCURRENCES

T/, :. 0Pz*OGCB: J0BA 4LRR i NRR DCKirkpatrck

KW man 11/15/89 11/12!89 rAINMENT CORROSION D/DOEA:NRR

CERossi 11/ /89*ESGB:DET:NRR

• (CPTan 11/21/89 C/OGCB:DOEA:NRR

CHBerlinger

11A918 C/ESGB:DET:NRR

Bagchi L1/21/89*RPB:ARM TechEd 11/17/89 D/DET: NRR V JRichardsW

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 you have any questions

about the of the technical

contacts listed no specific action or written response.

If information

In this notice, please contact one 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

• OGCB:DOEA:NRR

EMTB:DET:NRR

DCKirkpatrick

KWichman 11/15/89 11/ /89 D/DOEA:NRR

CERossi 11/ /89 ESGB:DET:NRR

CPTan Aret 11/al /89 C/OGCB:DOEA:NRR

CHBerlinger

11/ /89 C/ESGJ -j~ hR GBag hi V 11/n /89*RPB:ARM TechEd 11/17/89 D/DET: NRR JRichardson

11/ /89

-vi 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 lektt-i LLret ted visual inspectionv'

Considering

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 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