ML20113C655

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Responds to NRC 841022 Questions Re Methods for Surveillance & Control of Asiatic Clams.Info Previously Submitted Per Encl Refs.Documentation for IE Bulletin 81-03 Submittal Reviewed in NRC Insp Rept 50-334/81-15.Closeout Requested
ML20113C655
Person / Time
Site: Beaver Valley
Issue date: 01/14/1985
From: Sieber J
DUQUESNE LIGHT CO.
To: Varga S
Office of Nuclear Reactor Regulation
References
RTR-NUREG-CR-3054 IEB-81-03, IEB-81-3, NUDOCS 8501220386
Download: ML20113C655 (3)


Text

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'Af Telephone (412) 3934000 N

e r D,Mslon Shippingport, PA 15077@04 January 14, 1985 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Attn: Mr. Steven A. Varga, Chief '

Operating Reactors Branch No. 1 Division of Licensing Washington, DC 20555

Reference:

Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 IE Bulletin 81-03 Gentlemen:

This letter is in respolise to your letter dated October 22, 1984 entitled, " Survey Questions on Nuclear Power Plant Biofouling." Your letter requested a response to two questions regarding the methods for sur-veillance and control of asiatic clams.

A review of our previous submittals on this subject indicates that the infonnation being requested has already been provided by Duquesne Light Company. Reference to our submittals has been provided in the attachment to this reply. In addition, substantiating documentation for the Bulletin sub-mittal was reviewed in NRC Inspection 50-334/81-15. Inspection Report 81-15 stated, ". . . The licensee appears to have adequate methods in place for preventing and detecting flow blockage or degradation due to clams, mussels or shell debris based on the recent history of clam and mussel presence in the vicinity of the station. . ."

It is noted that NUREG/CR-3054 dated June 1984 places Beaver Valley Unit 1 in the " Units with High Biofouling Potential" category. The surveil-lance and control methods which are in place have not revealed any substantial evidence that Corbicula present a high biofouling risk. The most notable existence of Corbicula is found in the silt in the cooling tower's basin and upper dist ibution rings; however, an inspection made in October 1984 during plant refueling showed less evidence of corbicula than in the past. In our 1983 tesponse to the request for additional infonnation for IE Bulletin 81-03, the potential for clam intrusion under " worst-case" conditions was addressed. We stated that ". . . the potential for intrusion of Corbicula would be high. . ." This was based, however, upon a theoretical and dramatic increase in organism population in the river. Even for this postu-lated case, the prevention and detection methods outlined in the original response should alert plant personnel to potential flow degradation due to clam debris.

8501220386 850114 PDR ADOCK 0500G334 1 i

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_ - ._ = _ _ _ _ . -.

O January 14, 1985 Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 IE Bulletin 81-03 Page 2

, Therefore, it is Duquesne Light Company's position that it is more appropriate for Beaver Valley Unit 1 to be included in the NUREG category i- entitled, " Units with Low or Future Biofouling Potential," since these organisms do not appear to pose a serious biofouling threat.

Further, since we meet the NUREG " Criteria for Bulletin Closeout" in that we have submitted an acceptable program for detecting and preventing future flow blockage or degradation due to clams and have programs to con-firm adequate flowrates in the safety-related systems, this Bulletin should be considered " Closed" for our facility.

Very truly yours, J. D. Sieber Senior Manager Nuclear Group Attachment cc: Mr. W. M. Troskoski, Resident Inspector U.S. Nuclear Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 Mr. Peter Tam, Project Manager U.S. Nuclear Regulatory Commission Phillips Building Washington, DC 20555

-Mail Stop 438-

. U.S Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 Director, Safety Evaluation and Control Virginia Electric & Power Company P.O. Box 26666 One James River Plaza Richmond, VA 23261 1

ATTACHMENT QUESTIONS REGARDING SURVEILLANCE AND CONTROL METHODS

1. Discuss in detail, the surveillance methods that are being used to detect the presence of asiatic clams and/or mussels in the plant water supplies, fire protection systems, and systems which provide cooling for safety-related systems.

Response

A listing of the surveillances performed on potentially affected fire protection and safety-related systems was provided as an attachemnt to the Beaver Valley Unit 1 (J. J. Carey to E. L. Jordan) response, dated February 14, 1983, to the NRC request for additional information regarding IE Bulletin 81-03.

2. Discuss, in detail, the methods being used to control asiatic clams and/or mussels in the plant water supplies and systems in question 1.

Discuss the consideration given to systems required to mitigate trans-ients and/or accidents where those systems are not used during nonnal opera tion. Discuss the consideration given to protect heat transfer surfaces from clam and/or mussel infestation.

Response

The Beaver Valley Unit 1 (J. J. Carey to B. H. Grier) response, dated May 26, 1981, to IE Bulletin 81-03 stated, ". . . we have determined that clams are not causing a degradation of cooling systems at Beaver Valley Power Station, Unit No.1. In addition to present prevention and detection methods, visual inspections for clams have been added to existing procedures to aid in detecting any future increase in clam infestation of cooling systems. The prevention and detection methods used presently and planned for the future should provide adequate indication of clam debris." Therefore, no additional methods are necessary for the control of clams.