ML20008G328
| ML20008G328 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 06/17/1981 |
| From: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 957, IEB-81-03, IEB-81-3, NUDOCS 8107070322 | |
| Download: ML20008G328 (5) | |
Text
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THE CINCINNATI GAS & ELECTRIC COMPANY is --
CINCIN N ATI OHIO 4 52ol June 17, 1981 ulo^d$c"U((o".o
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U. S. Nuclear Regulatory Commission
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l Office of Inspection and Enforcement
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Region III jt)(0 g $p 7 799 Roosevelt Road
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CC Attn: ' r. James G. Koppler, Regional Director g
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Re:
WM. H. ZIMMER NUCLEAR POWER STATION - UNIT 1 RESPONSES TO IE BULLETIN 81-03, FLOW BLOCKAGE OF COOLING WATER TO SAFETY SYSTEMS COMPONENTS BY CORBICULA SP. (ASIATIC CLAM) AND MYTILUS SP. (MUSSEL)
W.O. 57300, JOB E-5590, FILE //957 Gentlemen:
The following information is being furnished in response to IE Bulletin 81-03, regarding flow blockage of cooling water to safety systems components by Corbicula sp. (Asiatic Clem) and Mytilus sp. (Mussel).
This information covers the three (3) items of inquiry pertaining to IE Bulletin 81-03 for holders of construction permits, dated April 10, 1981.
The Cincinnati Gas & Electric Co. response consists of the following:
1.
Determine whether Corbicula sp. or Mytilus sp. is present the vicinity of the station by completing items 1 and 4 above that apply to operating licenses (OL).
Item 1 as referenced above consists of the following question:
I 1.
Determine whether Corbicula sp. or Mytilus sp. is present in the vicinity of the station (local environment) in either the source or receiving water body.
If the results of current field monitor'.ng l
programs provide reasonable evidence that neither of these species is present in the local environment, no further action is necessary except for items 4 and 5 in this section for holders of operating licenses.
Item 4 at referenced above conshts of the following question:
4.
Describe methods either in use or planned (including implementation date) for preventing and detecting future flow blockage or degrada-tion due to clams or mussels or shell debris.
Include the following information in this description:
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~U. S. Nuclscr R:gulatory Commission.
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- Region III Mr. Jam 2a G. Kzppler,.Dirsctor k' -
-June 17, 1981
'Page 2.
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- a. L Evaluation of the potential for. intrusion of the organisms into these systems due to low water level and high velocities in the intake structure expected during worst case conditions.
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- b. : Evaluation of effectiveness of prevention and detection methods used in the past or present or planned for future use.
RESPONSE
i
- 1. 1 Review of the Environmental Report, page 2.7-15, determined that.
Corbicula sp. is.present in the Ohio River in the vicinity of Zimmer Station.
Specifically, "the, Asiatic Clam, the most common mollusk in the. area, was collected on every. trip except November.
Though commonly I
found, it'was not abundsnt."' Mytilus sp. has not been encountered in the Ohio River in the vicinity.of Zimmer Station.
4.
The present method of detecting flow blockage.or degradation due to clams or shell~ debris consists of a thorough inspection of the emergency diesel. generator cooling system..On June 9, 1981, four r
(4) diesel generator heat exchangers were dismantled and visually
-inspected for clam infestation by the Electric Production Department (EPD). These components of the service water system were chosen for inspection because they are currently fully _ operational and therefore most indicative of present and future-infestations. The investigation revealed no-clam infestation in the heat exchanger, and negligible
-evidence of shell debris (3 shells of " diameter removed from 4 heat exchangers).
It is inferred that cll other potentially affected 1,
-components are likewise uninfested.
lDue planned method of preventing and detecting future flow blockages i
or degradation due to clams or shell debris shall consist of dis-
. mantling and visually inspecting at least one heat exchanger in each service water subsystem.
If clams and debris are present, the l
remaining. heat exchangers will be inspected and hand cleaned as necessary.
This plan will be implemented just prior to fuel loading and will continue during each refueling outage.
The Fire Protection ' System is presently being monitored for blockages by flushing various lines approximately every six (6) months. To this date, no evidence of clam infestation or debris has been present during flushing cycles.
Prior to fuel loading, the NRC's comprehensive plan for routine sur-
-veillance of Fire Protection Systems according to the Tech. Specs.
will be implemented. This routine flushing plan should detect clam infestation and prevent future clogging.
If clogging does occur 1 uring the six (6) month flushing interval, the affected pipes-will d
be mechanically-cleaned and closer monitoring may be required.
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.U.LS. Nuciscr Rigulctory Commission Mr. James G. Kepplsr, Dirsctor
' Region:III
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' June 17, 1981 Page.3.-
-a..
Potential for intrusion of Corbicula sp. due to low water, level l
and high. velocities is considered minimal due to the design of.
-the intake structure. According to the Environmental Report,
-- page 3.4-1, -the. maximum water. withdrawal rate is 52,500 gpm and would occur only at a 100% plant load fdcter. Ihis water with-drawal rate will result in an approach velocity to the~ traveling screens' of less than 0.5 f t/sec. The bottom of the intake flume
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is located approximately.18 ft. below the nr,rmal river elevation of. 455 mal, and. low water levels are not expected to increase
. flow rate above 0.5-ft/sec, even for worst case conditions.
b.:
These programs of routinely inspecting the service water and 1
Fire Protection Systems for intrusion of clams and shell debris have thus1far been effective. Revisions to the plan may become
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necessary when the plant becomes cperational and the extent of intrusion becomes more evident.
2.
If.these organisms are present in the local environment and potentially i
affected systems have been filled from the station source or receiving water body, determine-whether. infestation has occurred.
RESPONSE
1
- On June 9, 1981, four (4) diesel generator heat exchangers were dismantled and visually inspected by - EPD-of The Cincinnati Gas & Electric Company (CG&E). No evidence of fouling due to clams' and negligible evidence of I
shell debris were discovered at this time. These components of the service water system should experience infestation first since they are currently fully. operational and water temperatures are conducive to r
Corbicula sp. growth. OG6E is therefore confident that the remainder of the system is unfouledi Detection and'preventidnLof. future blockages will oegin' prior to fuel
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loading. : At =this time one (1) heat exchanger in each service water
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subsystem will be dismantled and visually inspected for the presence of clams or shell debris.. This procedure will be repeated during each fueling outage.
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The Fire. Protection System is presently flushed approximately semi-annually at various hose connections, and has shant no signs of blockage
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or degradation.
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- 3. ' Describe'the actions taken in items 1 and 2 above for construction permit holders and include the'following information:
I
- a.. Applicable portions of the environment monitoring program including
.E last sample date and results.
- b... Components.and systems.a"fected.
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U. S. Nucle:r Rsgulctory Commicsion M. James C. Keppler, Director-r Cg Region III June 17, 1981 Page 4.
c.
F.xtent af fouling if any existed.
d.
How and when fouling was discovered.
e.
Corrective and preventive actions.
RESPONSE
a.
During 1973 Wapora, Inc. conducted the biological baseline study at Wm. H. Zimmer Power Station. 'This report was published in early 1974.
During 1975-1976 Applied Biology, Inc. and the Department of Bio-logical Sciences of the University of Cincinnati (ABI-UC) conducted the Construction Phase Monitoring Program at Zimmer Station. This report was published in July, 1977.
Both studies collected Corbicula sp. from the processed river bottom samples taken from the vicinity of Zimmer Station. The ABI-UC report shows'Corbicula sp. to be especially prevalent during the summer months.
b.
The components and systems potentially affected include the following:
1.
Intake Flume 2.
Intake Structure 3.
Service Water Piping System - Water Boxes, Coolers, etc.
4.
Cooling Tower Basin and Condenser 5.
Fire Water System 6.
Emergency Diesel Generator Cooling System.
Of the above listed items, -(1) Intake Flume, (2) Intske Structure, and (4) Cooling Tower Basin and Condenser are considered unlikely aieas for infestation due to design and/or location in the water system. The remaining items will be the basis for monitoring clam
. infestation until future conditions warrant more extensive examination.
c.
Of these components and systems listed above, the Fire Water System and Emergency Diesel Generator Cooling System are deemed indicative
-of current infestation and have been monitored thus far.
Tests of these systems show no evidence of fouling.
d.
Thus far fouling of any of the systems has not been discovered.
Further investigation of heat exchangers in each service water sub-system will begin prior to fuel loading and continue during each
-refueling outage.
O.
M Mr.. Jam 32 C. K:pplsr, Dirsctor U. S. Nuclear Rrgulatory Commission Region III h
June 17,'1981 Page 5.
e.
If fouling of the service water system becomes a problem, the clams and/or debris will be removed from the heat exchangers by hand. All heat exchangers in a subsystem will be examined if the routine ins-pection indicates infestation.
It is believed that routine inspec-tion and cleaning will prevent flow levels from falling below minimum acceptable levels.
If fouling of the Fire Protection System is detected, the system will require cleaning by means of mechanical cleaners, such as pipe snakes.
It is believed that routine flushing of the system will prevent clogging. All prevention / detection plans are subject to upgrading if current practices prove inadequate for operational plant conditions.
Very truly yours, THE CINCINNATI GAS & ELECTRIC COMPANY
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BY E. A, Borgmann PEB/jb Enclosure
- cc: NRC Office of Inspection and Enforcement Division of Reactor Inspection Programs Washington, D.C. 20555 F. T. Daniels NRC Resident Inspector R. F. Scheibel B. K. Culver S. G. Salay J. R. Schott H. R. Sager J. D. Flynn H. C. Brinkmann H. E. Crail J. C. Herman P. E. Bogen W. D. Waymire (pink)
Attn: Gen. File R. A. Beck
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