ML20115E016
| ML20115E016 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 10/19/1992 |
| From: | Helwig D PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-13, NUDOCS 9210210300 | |
| Download: ML20115E016 (2) | |
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PHILADELPlHA ELECTRIC COMPANY-
.o LIMERICK GENERATING STATION P. O,- BOX 2300' l
SANATOGA, PA 19464 2300 i
ms> m.nw. err. aow f
DAM,yTO October 19,-1992 I%iERO GENERA. 20 UATKW Docket Nos.-
50-352 i
50-353-l License Nos. NPF-39 NPF-85 l
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U.S. Nuclear Regulatory Commission 6-Attn Document Control. Desk
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Washington, DC ~20555:
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SUBJECT:
Limerick Generating-Station, Units l'and 2 Generic Letter 89 13, " Service Water Problems Affecting. Safety-Related Equipment" j
Implementation of Actions l
REFERENCES:
- 1) Letter from G. J.. Beck, PECo, to.USNRC,-
(
" Generic Letter 89-13, ' Service' Water-Problems i
lAffecting' Safety-Related Equipment' Implementation-of Actions," dated August 5, 1991
- 2) Telecon with R. Clark-USNRC:and D. Neff',-
C. Hetrick, S. Dietch,:PECo-LGS,7 June 11,'1992~-
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I The referenced: letter committed to modifying the:
I chlorination program to extend:treatmentEto~the. Emergency Service; hater (ESW) system and the Residual Heat Re*. oval Service-
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i' Water (RHRSW)' system components.
This commitment'was-
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-implemented to minimize _biofouling of the^as_sociated-heat ~-
exchangers and. enable system lay-up with chlorinated water:as
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l recommendedLby Generic Letter 89-13.
This-letter 1 changes our j.
cammitment'to use chlorinated' water 1in the?ESW and RHRSW systems'.
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--Recent! testing of the Residual-Heat-Rrmoval_(RIi2)'. beat
-exchangers has. revealed. tube-side: fouling with. manganese.
The presence-of this deposit promotes corrosion. pits on-theitube surface.- Duento-the high manganese;contentLof. makeup waters,-
continued chlorination of these' waters may accelerate the deposition rate.-.Therefore,-'.chlorinati-on was suspended-as l
. agreed upon-in the referenceditelecon.
i 9210 fib 300 921019 I h
'PDR, ADOCK 05000352.
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PDR-
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- We are conducting an extensive investigation to more completely define the effect of manganese and chlorination on stainless steel surfaces.
The available-literature-and related testing indicates that manganese deposition and the resulting-pitting on stainless steel is predominantly a function of heat transfer; however, there is conflicting information regarding chlorination.
Additionally, the presence of large populations of biological organisms in the heat exchanger deposits indicates that chlorination was providing inadequate control.
To control and reduce the incidence of heat transfer degradation due to biofouling, we have changed our program to utilize a non-oxidizing blocide for the ESW and RHRSW systems.
A program is in place at this time for treating the RHRSW system.
Inclusion of the'ESW system into the program is currently under review.
The dosages, blocides and treatment j
frequencies will be determined based on plant monitoring, vendor recommendations, and industry experience.
It is anticipated that inclusion of the'ESW system into.the program will occu: by j-December 1, 1992.
If you have any questions, or require additional-information, please contact us.
Very truly yours,
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JLP:cah cc:
T. T. Martin, Administrator, Region I, USNRC T.
J. Kenny, USNRC Senior Resident Inspector, LGS i
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