ML20004F633
| ML20004F633 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/22/1981 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-81-03, IEB-81-3, NUDOCS 8106190303 | |
| Download: ML20004F633 (2) | |
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1 W PowEn couNNY 231 W. MICHIGAN P.O. BOX 2044. MILWAUKEE. WI 53201 May 22, 1981 Mr. James G. Kappler, Regional Director Office of Inspection and Enforcement, si, g Region III
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Dear Mr. Keppler:
E 9.s, demi;[4ren R DOCKET NOS. 50-266 AND 50-301 M
f RESPONSE TO IE BULLETIN 81-03 N% /Dbg'\\
FLOW BLOCKAGE BY ASIATIC CLAM POINT BEACH NUCLEAR PLANT UNITS 1 AND 2 IE Bulletin 81-03 discussed the flow blockage of safety system components at a nuclear facility by Asiatic clams, (Corbicula species) a fresh water bivalve mollusk.
All licensees were required to determine whether Corbicula species (or Mytilus species if ser-viced by a salt water cooling system) is present in the vicinity of their nuclear station in either the source or receiving water.
Point Beach Nuclear Plant 16 located on the shores of Lake Michigan, a fresh water lake.
The plant's cooling water and service water is taken from and returned to Lake Michigan.
Based on the sampling experience of an intensive five year environmental sampling program at the Point Beach Nuclear Plant, the Asiatic clam has not been detected in the vicinity of the plant.
A summary report of the environmental sampling program was sent to the NRC with our letter dated July 3, 1978.
We have also surveyed other utilities with operating plants located on Lake Michigan and determined that the Asiatic clam has not been encountared in the vicinity of their plants.
Since these plant sites have also been surveyed intensely over a number of years, we consider that it is highly unlikely that the Corbicula species resides in Lake Michigan.
Additionally, based on available life history information for clams of this variety, it is unlikely thar Corbicula would ever become established in the Point Beach area.
Clams of this variety are not found in clay or rock bottom nor do they prefer shifting sand or gravel substrates.
These characteristics describe the existing substrate in the vicinity of Point Beach.
The relatively cold waters of Lake Michigan also make Asiatic clam habitation unlikely.
The bulletin also directed that licensees describe methods either in use or planned for preventing and detecting future flow blockage
<>r degradation due to clams, mussels, or shell debris.
As discussec. above, due to the absence of this species in the local l
81oc n o 303
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i e..~ 6 Mr. James G. Keppler 'May 22, 1981 envirosament, we do not expect any such flow blockage or degrada-tion.
The=only service water heat exchanger restriction experienced at Point Beach has been associated with inorganic suspended matter (dirt and sand) dropout in some conducive piping configurations or low velocity zones.
These restricting configurations are under refueling frequency surveillance programs of disassembly and flushing.
In normal operation, system and equipment differential pressures and flows are also regularly monitored--for indications of service water flow degradation.
No growing organisms have ever been discovered in Point Beach Nuclear Plant service water systems,-or in the circulating water system between the main circulating water pumps and the discharge pipe loop seal.
The reason for this principally. relates to the cold water temperatures at Point Beach Nuclear Plant and the scrubbing action of fine sand which periodically mobilizes and entrains in -the circulating and service water systems.
As a consequence, Point Beach has never needed water chlorination or condenser tube brushing.
Therefore, we would consider any further methods of monitoring or control of organism growth or fouling at Point Beach as unnecessary.
Very truly yours, ll
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C. W. Fay, Director Nuclear Power Department Subacribed and sworn to before me This 22nd day of May, 1981.
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Notary Public, State oi Wisconsin My commission expires 7- [- f d i
Copy to NRC Resident Inspector y,.,---__,___..r
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