ML20029E669
| ML20029E669 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 05/13/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20029E668 | List: |
| References | |
| NUDOCS 9405190288 | |
| Download: ML20029E669 (3) | |
Text
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Mr.. John R. McGaha Entergy Operations, Inc.
River Bend Station cc:
Winston & Strawn Mr. Harold W. Keiser ATIN: Mark J. Wetterhahn, Esq.
Executive Vice President and 1400 L Street, N.W.
Chief Operating Officer Washington, D.C. 20005-3502 Entergy Operations, Inc.
P. O. Box 31995 Mr. Otto Bulich Jackson, Mississippi 39286 Director - Nuclear Licensing Entergy Operations, Inc.
Mr. Michael B. Sellman River Bend Station Plant Manager.
St. Francisville, Louisiana 70775 Entergy Operations, Inc.
River Bend Station Mr. Philip G. Harris Post Office Box 220 Cajun _ Electric Power Coop, Inc.
St. Francisville, Louisiana 70775 10719 Airline Highway P. O. Box 15540 Mr. James J. Fisicaro Baton Rouge, Louisiana 70895 Manager - Safety Assessment and Quality-Verification Senior Resident Inspector Entergy Operations, Inc.
P. O. Box 1051 River Bend Station St. Francisville, Louisiana 70775 Post Office Box 220 St. Francisville, Louisiana 70775 President of West Feliciana Police Jury Mr. Jerrold G. Dewease P. O. Box 1921 Vice President - Operations Support St. Francisville, Louisiana 70775 Entergy Operations, Inc.
P. O. Box 31995 Regional Administrator, Region IV Jackson, Mississippi. 39286-1995 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 The Honorable Richard P. Ieyoub Arlington, Texas 76011 Attorney General State of Louisiana William G. Davis, Esq.
P. O. Box 94095 Department of Justice Baton Rouge, Louisiana 70804-9095 Attorney General's Office P. O. Box 94095 Baton Rouge, Louisiana 70804-9095 Ms. H. Anne Plettinger 3456 Villa Rose Drive j
Baton Rouge, Louisiana 70806 Administrat'or Louisiana Radiation Protection Division P. O. Box 82135 Baton Rouge, Louisiana 70884 2135 9405190288 940513 PDR ADOCK 05000458 P
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UNITED STATES 7;(gk, f NUCLEAR REGULATORY COMMISSION WASHINGTON D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO CHANGES TO THE ASIATIC CLAM CONTROL PROGRAM ENTERGY OPERATIONS. INC.
RIVER BEND STATION DOCKET NO. 50-458
1.0 INTRODUCTION
The licensee's response to NRC Bulletin (NRCB) 81-03, " Flow Blockage of Cooling Water to Safety System Components by Corbicula Sp. (Asiatic Clams) and Mytilus Sp. (Hussel)," resulted in the establishment of a program to prevent biofouling of safety-related equipment at River Bend Station.
This program is enforced through Technical Specification (TS) 6.8.4.d, which states that a biofouling prevention and detection program shall be maintained in effect and that any changes to the program must be submitted to and approved by the NRC.
The license implements this requirement via its Asiatic Clam Control Program (ACCP).
Prior to refueling outage four (RF4), the River Bend Station service water system (SWS) was an open cycle system using clarified Mississippi River water.
Over time, the facility experienced problems with corrosion product buildup, microbiologically induced corrosion, localized pitting, degraded flow, and mud and silt accumulation within the SWS.
As a result of these problems, the licensee undertook a major modification of the SWS during RF4 to convert the system from an open to a closed cycle system.
Closure of the SWS would be expected to eliminate the risk of clam infestation for which the ACCP was instituted; however, the licensee has continued to perform the inspections and analyses required by the program to obtain operational data to support this conclusion, and to verify that no clams remained in the system following its closure.
In a letter dated January 14, 1994, the licensee requested NRC approval of the following changes to the ACCP: (1) delete sampling and analysis of sediments at the intake embayment and normal cooling tower basins; (2) delete sampling and analysis at the clarifier influent and effluent; and (3) delete visual inspections, sampling, and performance monitoring of safety-related heat exchangers that interface with service water.
2.0 EVALUATION With' respect to deletion of sampling and analysis of sediments at the intake embayment and cooling tower basins, and of the clarifier influent and effluent, the licensee stated that the source of makeup to the SWS is no longer the Mississippi River. The clarified Mississippi River water provided i
. the source for Asiatic clams and the open cycle service water system provided the pathway for infestation of the SWS and associated safety-related equipment. The closed cycle SWS now uses demineralized water or well water as the source of makeup water. The licensee stated that, since the modifications in design and operation of the SWS have eliminated the possibility of Asiatic clam infestation from the Mississippi River, the subject sampling and analyses are not necessary.
Based on the above, deletion of these requirements is acceptable to the staff.
Though considered to be a highly unlikely event, the licensee provided its analysis of the potential for introduction of Asiatic clams into the SWS via 3
avian transport of juvenile clams into the standby cooling tower (SCT) basin.
The licensee stated that the SCT basin water is treated with a microbiocide and maintained at a high (9-9.5) pH level.
Tests conducted for the licensee indicated that this environment will be effective in preventing infestation of the SWS via this pathway.
The licensee stated that they have continued to perform inspections and performance monitoring of safety-related heat exchangers in order to insure that closur.e of the SWS has precluded the possibility for further clam infestations.
Inspections and performance monitoring to date have shown no evidence of clam infestations.
The licensee stated that this monitoring experience, in conjunction with the highly unlikely occurrence of future clam infestation in the closed loop SWS, provide the basis for deletion of the heat exchanger sampling and performance monitoring requirements from the ACCP.
Based on the observed lack of clam infestation since closure of the SWS, and the low probability for future introduction of clams into the SWS, deletion of the inspection and performance monitoring requirements from the ACCP is acceptable to the staff.
The staff questioned the licensee regarding the need for a change to TS 6.8.4.d, indicating that the removal of the requested items from the program, while technically acceptable, appeared to present a situation wherein the licensee would not be in compliance with the TS as written.
The licensee responded to the staff's concerns in a letter dated April 6,1994, stating that the planned revisions to the ACCP would continue to meet the intent of l
the TS.
The licensee stated that the biofouling prevention and detection program would continue to be maintained in effect, using less intrusive inspection and performance monitoring requirements based on the favorable experience since closure of the SWS during RF4.
The licensee stated that they_
would review the TS for possible changes following implementation of all procedural resisions. This is acceptable to the staff; therefore, no changes to the TS are required at this time.
3.0 CONCLUSION
Based on the above information, the staff (both NRR and Region IV) concludes that the subject sampling, anal.,
s, inspection, and performance monitoring requirements are no longer required and the proposed modifications to the
Asiatic Clam Control Program do not require a change to the technical specifications.
Therefore, the staff finds the licensee's proposal acceptable.
Principle Contributor:
Robert G. Schaaf, PD IV-1 Date: May 13, 1994 i
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