ML20004F310
| ML20004F310 | |
| Person / Time | |
|---|---|
| Site: | Monticello, Dresden, Davis Besse, Palisades, Perry, Kewaunee, Point Beach, Byron, Braidwood, Prairie Island, Callaway, Duane Arnold, Clinton, Cook, Quad Cities, La Crosse, Big Rock Point, Zion, Midland, LaSalle, 05000452, Zimmer, Bailly, Marble Hill  |
| Issue date: | 04/10/1981 |
| From: | Carroll D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8106180139 | |
| Download: ML20004F310 (2) | |
Text
,e*arrug'e, UNITED STATES c['3, ~j NUCLEAR REGULATORY COMMISSION O
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Gentlemen:
The enclosed IE Bulletin No. 81-03 titled " Flow Blockage of Cooling Water to Safety System Components by Corbicula SP. (Asiatic Clam) and Mytilus SP. (Mussel)" was sent to the licensees listed below for information and action on April 10, 1981:
American Electric Power Service Corporation Indiana and Michigan Power Company D. C. Cook 1, 2 (50-315, 50-316)
Cincinnati Gas and Electric Company Zimmer (50-358)
Cleveland Electric Illuminating Company Perry 1, 2 (50-440, 50-441)
Commonwealth Edison Company Braidwood 1, 2 (50-456, 50-457)
Byron 1, 2 (50-454, 50-455)
Dresden 1, 2, 3 (50-10, 50-237, 50-249)
LaSalle 1, 2 (50-373, 50-374)
Quad-Cities 1, 2 (50-254, 50-265)
Zion 1, 2 (50-295, 50-304)
Consumers Power Company Big Rock Point (50-155)
Palisades (50-255)
Midland 1, 2 (50-320, 50-330)
Dairyland Power Cooperative LACBWR (50-409)
Detroit Edison Company Fermi 2 (50-452)
Illinois Power Company Clinton 1, 2 (50-461, 50-462) 8106180/N p
^*- '+
Iowa Electric Light & Power Company Duane Arnold (50-331)
Northern Indiana Public Service Company Bailly (50-367)
Northern States Power Company i
Monticello (50-263)
Prairie Island 1, 2 (50-282, 50-306)
Public Service of Indiana Marble Hill 1, 2 (50-546, 50-547)
Toledo Edison Company Davis-Besse 1 (50-346)
Union Electric Company Callaway 1, 2 (50-483, 50-486)
Wisconsin Electric Power Company Point Beach 1, 2 (50-266, 50-301)
Wisconsin Public Service Corporation Kewaunee (50-305)
Sincerely,
)
c(A '
orothy E.
rroll, Chief Word Proces ing and Document Control Section
Enclosure:
1
SSINS No.: 6820 Accession No.-
8011040289 IEB 81-03 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 April 10, 1981 IE Bulletin 81-03 :
FLOW BLOCKAGE OF COOLING WATER TO SAFETY SYSTEM COMPONENTS BY CORBICULA SP. (ASIATIC CLAM) AND, MYTILUS SP. (MUSSEL)
Description of Circumstances:
On September 3, 1980, Arkansas Nuclear One (AND), Unit 2, was shut down after the NRC Resident Inspector discovered that Unit 2 had failed to meet the technical specification requirements for minimum service water flow rate through the containment cooling units (CCUs).
After plant shutdown, Arkansas Power and Light Company, the licensee, determined that the inadequate flow was due to extensive plugging of the CCus by Asiatic clams (Corbicula species, a non-nativt fresh water bivalve mollusk).
The licensee disassembled the service water-piping at the coolers.
Clams were found in the 3-inch diameter supply piping at the inlet to the CCOs and in the cooler inlet water boxes.
Some of the clams found were alive, but most of the debris consisted of shells.
The size of the clams varied from the larvae stage up to one inch.
The service water, which is taken from the Dardanelle Reservoir, is 'iltered before it is pumped through the system.
The strainers on the service water pump discharges were examined and found to be intact.
Since these strainers have a 3/16-inch mesh, much smaller than some of the shells found, it appears that clams had been growing in the system.
Following the discovery of Asiatic clams in the containment coolers of Unit 2, the licensee examined other equipment cooled by service water in both Units I and 2.
Inspection of other heat exchangers in the Unit 2 service water system revealed some fouling or plugging of additional coolers (seal water coolers for both redundant containment spray pumps and one low pressure safety injec-tion pump) due to a buildup of silt, corrosion products, and debris (mostly clam shell pieces).
The high pressure safety injection (HPSI) pump bearing and seal coolers were found to have substantial plugging in the 1/2-inch pipe service water supply lines.
The plugging resulted from an accumulation of silt and corrosion products.
Clam shells were found in some auxiliary building room coolers and in the
_auxiliarv cool.inq,wMer_ sustam whiebf arves non-safety related equipment.
g, testing through the CCUs at AND-2 had DUPLICATE DOCUMENT
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