Information Notice 1985-30, Microbiologically Induced Corrosion of Containment Service Water System

Microbiologically Induced Corrosion of Containment Service Water System

ML070180069
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, Skagit, Marble Hill
Issue date:	04/19/1985
From:	Jordan E NRC/IE
To:
References
IN-85-030, NUDOCS 8504170240
Download: ML070180069 (4)

SSiNS No.: 6835 IN 85-30

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 April 19, 1985 IE INFORMATION NOTICE NO. 85-30: MICROBIOLOGICALLY INDUCED CORROSION OF

CONTAINMENT SERVICE WATER SYSTEM

Addressees

All holders of a, nuclear power reactor operating license (OL) or construction

permit (CP).

Purpose

This information notice is provided to alert recipients of significant corro- sion pitting due to microbiologically induced corrosion identified in stainless

steel piping sections of a service water system after an extended plant outage.

It is expected that recipients will review the information for applicability to

their facilities and consider actions, if appropriate, to preclude similar

problems occurring at their facilities. 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 January 26, 1984, H. B. Robinson Unit 2 was shut down and remained shut down

throughout the year to replace the lower assemblies of the steam generator and

perform other maintenance work.

On November 19, 1984, Carolina Power and Light Company (CP&L) reported that

minor pinhole leaks were found in the heat affected zones of circumferential

welds joining 6-inch diameter, Schedule 10, 304 stainless steel piping that

provides service water to the four containment chilling units. Visual inspec- tion of the entire system revealed minor leakage at a total of 54 weld joints,

32 inside and 22 outside containment. Further radiographic examination re- vealed evidence of localized corrosion pitting on the inside surface at many

other austenitic piping weld joints of the system. Numerous sleeve assemblies

were required to restore integrity of the weld.s degraded by the corrosion

attack.

Discussion:

The licensee's investigation determined that the root cause of the problem was

the result of microbiologically induced corrosion (MIC). This is representa- tive of several similar incidents reported in construction and operating plants

in past years. A very recent example may be'a large number of leaking welds in

8504170240

IN 85-30

April 19, 1985 the Essential Spray Pond Piping System at Palo Verde Unit 2. The licensee's

evaluation is currently underway, but their preliminary conclusion is the

problem is caused by MIC.

MIC is a form of corrosive action that occurs as a direct, or indirect, result

of living organisms in contact with the materials of construction. Microorgan- isms have been observed in a variety of environments including soils, sediment, natural fresh water (e.g., wells, rivers, lakes), brackish and sea water, as

well as oil and other natural petroleum products. Many species may form

synergistic cross feeding support systems with other bacteria, fungi, algaes

and the like to enhance survival under the most adverse conditions. They have

been known to tolerate a wide-range of temperatures (-10 to 90 0 C), pH values of

0 to 10.5, oxygen concentrations from zero to almost 100 percent 02 and extreme

hydrostatic pressure. There are six different classifications of microorganisms

containing over 30 species that can be a problem, depending on the geographic

location and the environmental conditions.

The metabolic processes of organisms are sustained by chemical reactions.

These processes can significantly influence the corrosion behavior of materials

by (1) destruction of protective surface films, (2) creating corrosive deposits, and/or (3) altering anodic and cathodic reactions depending on the environment

and organism(s) involved.

Several general methods for inhibiting MIC have been employed with varied

degrees of success in recirculation systems. Among these methods were an

application of protective coatings in conjunction with cathodic protection, corrosion inhibitors, or water chemical treatment such as periodic shock

chlorination. However, it is important to correctly diagnose the presence of

MIC and the organisms involved before attempting such corrective measures to

ensure that no products are formed that themselves have a detrimental effect on

the materials. Moreover, if water chemical treatment is used, it is important

to ensure that residual chemical levels are maintained within the permissible

range of applicable EPA requirements.

Where the above measures are not practical, it has been observed that relative- ly rapid fluid flow tends to prevent attachment of organisms whereas low flow

rates or stagnant conditions favor biofouling and concentration cell corrosion.

Thus, cleaning and dry lay up, or periodic recirculation flushing, during

extencdd outages to mitigate know biological activity would appear to be

prudent alternatives.

IN 85-30

April 19, 1985 No specific action or written response is required by this information notice.

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

Administrator of the appropriate NRC regional office or the technical contact

listed below.

-dward L. Jordan /Oirector

Division of Emerrgency Preparedness

and Engineering Response

Office of Inspection and Enforcement

William J. Collins, IE

(301) 492-9630

Attachment:

List of Recently Issued IE Information Notices

Attachment I

IN 85-30

April 19, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-29 Use Of Unqualified Sources 4/12/85 All well logging

In Well Logging Applications source licensees

85-03 Separation Of Primary Reactor 4/9/85 All power reactor

Sup. 1 Coolant Pump Shaft And facilities holding

Impeller an OL or CP

85-28 Partial Loss Of AC Power And 4/9/85 All power reactor

Diesel Generator Degradation facilities holding

an OL or CP

85-27 Notifications To The NRC 4/3/85 All power reactor

Operations Center And facilities holding

Reporting Events In Licensee an OL or CP

Event Reports

85-26 Vacuum Relief System For 4/2/85 All BWR facilities

Boiling Water Reactor Mark .having a Mark I or

I And Mark II Containments Mark II containment

and holding an OL or

CP

85-25 Consideration Of Thermal 4/2/85 All power reactor

Conditions In Th2 Design And facilities holding

Installation Of Supports For an OL or CP

Diesel Generator Exhaust

Silencers

85-24 Failures Of Protective 3/26/85 All power reactor

Coatings In Pipes And Heat facilities holding

Exchangers an OL or CP

85-23 Inadequate Surveillance And 3/22/85 All power reactor

Postmaintenance And Post- facilities holding

modification System Testing an OL or CP

85-22 Failure Of Limitorque Motor- 3/21/85 All power reactor

Operated Valves Resulting facilities holding

From Incorrect Installation an OL or CP

Of Pinon Gear

OL = Operating License

- CP = Construction Permit