Biofouling Agent: Zebra Mussel

                                UNITED STATES
                           WASHINGTON, D.C.  20555

                              November 21, 1989

Information Notice No. 89-76:  BIOFOULING AGENT:  ZEBRA MUSSEL


All holders of operating licenses or construction permits for nuclear power 


This information notice is intended to alert addressees to potential 
problems related to biofouling of service water and cooling water systems 
that may result from a recently identified biofouling agent, Dreissena 
polymorpha (zebra mussel).  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.


The potential for biofouling has been of concern to the NRC since 1980 
because biofouling can compromise the vital transfer of heat to the ultimate 
heat sink.  The NRC issued Generic Letter (GL) 89-13, "Service Water System 
Problems Affecting Safety-Related Equipment," on July 18, 1989, requesting 
licensees to adopt either the specific recommended surveillance and control 
procedures delineated in the generic letter or an equally effective 
alternative course of action for preventing biofouling of their nuclear 
service water systems.  This aspect of the generic letter presents the 
results and recommendations from an NRC research program initiated in 1982 
when biofouling agents were noted to clog service water systems.  The 
principal biofouling agents noted in the generic letter were Corbicula 
fluminea (Asiatic clam), Crassostrea virginica (American oyster), and 
Mytilus edulis (blue mussel).  In 1980, the number of nuclear power plants 
directly affected by these agents was small, but by 1984 the infestation by 
these aquatic bivalves had spread to a large portion of the United States.

The following information about the zebra mussel is taken from the abstract 
of a paper given at the Electric Power Research Institute Service Water 
System Reliability Improvement Seminar at Charlotte, North Carolina, on 
November 6-8, 1989.  The paper is entitled, "The Zebra Mussel, 
Dreissena Polymorpha (Pallas, 1771), in North America:  Impact on Raw Water 
Users."  The authors are R. W. Griffiths, Ontario Ministry of the 
Environment, Ontario, Canada; W. P. Kovalak, Detroit Edison Company; and D. 
W. Schloesser, U.S. Fish and Wildlife Service. 


                                                       IN 89-76
                                                       November 21, 1989
                                                       Page 2 of 2

"The zebra mussel, Dreissena polymorpha (Pallas), is a small mollusc native 
to the Black, Caspian, and Azov Seas that was discovered in Lake Erie of the 
Laurentian Great Lakes of North America in 1988.  The mussel raises 
immediate concerns for raw water users because it can obstruct the flow of 
water through pipes, hoses, screens, and condensers when it occurs in 
substantial numbers.  Biofouling attributed to this mussel was observed at 
several power plants, water treatment plants, and processing and industrial 
facilities along Lake Erie in 1989.  At one power plant, densities as high 
as 700,000 per m 2 were observed in the intake canal in August.  In 
addition, large numbers were found in main steam condensers and in the 
service water system threatening operation of cooling, fire protection, and 
dust suppression systems.  Intakes of municipal water supplies along the 
Canadian and the United States shorelines have also been impaired.  In one 
southeast Michigan city, drinking water withdrawal from Lake Erie was 
reduced 45% by the mussel."  

The geographical area of immediate concern for this source of potential bio-
fouling is along the Great Lakes and major tributaries and canals.  This 
potential is the subject of an international conference at Rochester, New 
York, on November 28 and 29, 1989.  Additional information on the meeting 
may be obtained from Charles R. O'Neill, Jr., of New York Sea Grant at 
(716) 395-2638 or Don W. Schloesser of the U.S. Fish and Wildlife Service at 
(313) 994-3331.

This information notice requires no specific action or written response.  If 
you have any questions about the information in this notice, please contact 
the technical contact listed below or the appropriate NRR project manager. 

                              Charles E. Rossi, Director
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contact:  C. Vernon Hodge, NRR
                    (301) 492-1169

Attachment:  List of Recently Issued NRC Information Notices 


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