Information Notice 1988-82, Torus Shells with Corrosion and Degraded Coatings in BWR Containments

Torus Shells with Corrosion and Degraded Coatings in BWR Containments

ML031150069
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, 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, Crane
Issue date:	10/14/1988
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-88-082, NUDOCS 8810070114
Download: ML031150069 (3)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

October 14, 1988

NRC INFORMATION NOTICE NO. 88-82: TORUS SHELLS WITH CORROSION AND

Addressees

All holders of operating licenses or construction permits for boiling water

reactors (BWRs).

Purpose

This information notice is being provided to alert addressees to the discovery

of suppression pool steel shells with corrosion and degraded coatings in BWR

containments. 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

During recent NRC inservice inspections (50-220/88-09 and 50-410/88-09) at

the Nine Mile Point Nuclear Station (NMPNS), inspectors found that the inside

surface of the torus shell at UnIt 1, which was designed and constructed as

uncoated, had corroded.

Furthermore, the NRC inspectors' independent thickness

measurements of the torus shell revealed several areas in which the thickness

was at or below the minimum specified wall thickness.

Based on additional

analysis, it was determined that the shell thickness is acceptable until

June 1989 at which time the licensee will perform an ultrasonic reexamination

of the torus shell.

Based on the findings, the licensee is committed to take

corrective actions.

A recent survey of BWRs located in NRC Region I also revealed that some Mark I

tori had experienced degradation of the coating and that cleaning and recoating

were required. The cause of these degradations is not yet fully understood.

Discussion:

Although the torus shell thinning due to corrosion observed at NMPNS Unit 1 and the coating degradation in tori of other Region I plants have no immediate

effect on plant operation, the NRC staff considers these deficiencies to be

significant because the measured corrosion rates of torus shells are greater

than the corrosion rates assumed as part of the original design.

The torus

shell degradation, if it continues, may Jeopardize containment integrity.

8810070114

IN 88-82 October 14, 1988 Many licensees of BWR plants are currently required to perform periodic visual

inspections of the suppression pool steel shells or liners in accordance with

their technical specifications, but the methods used by licensees vary.

Some

licensees examine only those portions of the torus above the water line, and

others employ divers or use cameras to inspect submerged surfaces.

Such

inspections can only detect general degradation. Localized degradation such as

pitting can be detected most effectively by draining the torus and inspecting

it under dry conditions.

In view of the importance of the containment to the

health and safety of the general public, licensees may wish to review and

evaluate the adequacy of their containment surveillance programs to determine

if any problems similar to those described above exist at their plants.

This information notice also applies to suppression pools for other types of

BWR containments (Mark II and Mark III), whether built of steel or of concrete

with a steel liner, because the steel shell or liner may degrade through

disintegration of the paint system and /or corrosion of the base metal.

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

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

contact listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, D rector

Division of Operational Events Assessment

Chen P. Tan, NRR

(301) 492-0829 Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 88-82

October 14, 1988 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

88-81

Failure of Amp Window

Indent Kynar Splices

and Thomas and Betts

Nylon Wire Caps During

Environmental Quali- fication Testing

Unexpected Piping Movement

Attributed to Thermal

Stratification

Misuse of Flashing Lights

for High Radiation Area

Controls

10/7/88

10/7/88

10/7/88

88-80

All holders of OLs

or CPs for nuclear

power, test, and

research reactors.

All holders of OLs

or CPs for PWRs.

All holders of OLs

or CPs for nuclear

power reactors.

88-79

88-69, Supp 1

Movable Contact Finger

Binding in HFA Relays

Manufactured by General

Electric (GE)

9/29/88

All holders of OLs

or CPs for nuclear

power reactors.

88-78

88-77

88-76

Implementation of Revised

NRC-Administered Requali- fication Examinations

Inadvertent Reactor

Vessel Overfill

Recent Discovery of a

Phenomenon not Previously

Considered in the Design

of Secondary Containment

Pressure Control

Disabling of Diesel

Generator Output Circuit

Breakers by Anti-Pump

Circuitry

Potentially Inadequate

Performance of ECCS in

PWRs During Recirculation

Operation Following a LOCA

9/22/88

9/22/88

9/19/88

9/16/88

9/14/88

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for BWRs.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for W and

B&W-designea nuclear

power reactors.

88-75

88-74 OL = Operating License

CP = Construction Permit