ML18031B143
| ML18031B143 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/26/1987 |
| From: | Domer J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8702030501 | |
| Download: ML18031B143 (6) | |
Text
ACCESSION NBR:
FAC IL:50-259 AUTH. NAt1E DOMERi J. A.
RECIP. NAME GRACE> J. N.
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REGULATORY ORMATION DISTRIBUTION 'SYS
. (RIDS) 8702030501 DOC. DATE: S7/Oi /26 NOTARIZED:
NO DOCKET 0 Brogans Ferry Nuclear Potoer Stationi Unit ii Tennessee 05000259 AUTHOR AFFILIATION Tennessee Valley Authority RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Revises response to violations noted in Insp Rept 50-259/79-04. Corrective actions: surveys of groundwater inleakage performed on periodic basis to provide baseline data for estimates.
DISTRISUTION CODE:
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TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSEE 37401 5N 157B Lookout Place gQ26 $87 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Office of Nuclear Reactor Regulation Washington, D.C.
20555 Attention:
Dr. J. Nelson Grace BROWNS FERRY NUCLEAR PLANT (BFN) REVISED RESPONSE TO NRC ITEM NO. 50-259/79-04-02, YARD DEWATERING PUMPS Please reference TVA's letter from M. R. Wisenburg to J.
P. O'Reilly dated February 26, 1982 regarding resolution of groundwater problems at Browns Ferry Nuclear Plant (BFN).
The following information addresses the dewatering pumps originally identified in NRC Inspection Report 79-04 dated March 22, 1979, Item 50-259/79-04-02.
h In January 1979, during a period of heavy rainfall, groundwater inleakage was observed entering the Reactor Building on elevation 519.
The dewatering pumps at. the southeast corner of the Reactor Building were examined and found inoperable.
One pump'as repaired and placed back in service.
The decision was made to procure new dewatering pumps and dig two new wells.
TVA committed to installing these pumps in letters to J.'. O'Reilly from L. M. Mills dated October 5, 1979 and April 2, 1981, and from M. R. Wisenburg dated October 30, 1981 and February 26, 1982.
In 1980, soil settlement in various areas along the Reactor Building south wall was discovered (reference letter 'from H. J.
Green to J.
P. O'Reilly dated December 4, 1980).
Extensive studies were conducted to determine the cause of the settlement.
The conclusions reached in 1984 named thre'e primary causes:
normal soil consolidation, poor compacting of backfill during construction, and erosion of soil fines into the dewatering wells.
In addition, a building leakage test was performed in October 1983 with the dewatering pumps turned off.
The amount of groundwater observed entering the Reactor Building was not measurable but was described as minimal.
Based upon these investigations, a
decision was made to cease continuous operation of the dewatering pumps to decrease soil removal by way of the dewatering wells.
In June
- 1986, the dewatering pumps were placed under an administrative hold requiring shift engineer permission to be operated.
Previously, the pumps were run on an intermittent basis with no established control.
An ongoing monitoring program has revealed that soil settlement is stabilizing and the structures will continue to perform their safety function based on present total settlement and the rate of settlement.
TVA's objective is to permanently remove the dewatering, pumps from service.
In order to accomplish this objective.TVA will assess the potential for failure of safety-related equipment caused by groundwater inleakage, 8702030501 870126 PDR ADQCK 05000259 8
PDR An Equal Opportunity Employer
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U.S. Nuclear Regulatory Commission Ff+26 $87 particularly during a probable maximum flood (PMF) as defined in sections 2.4.2.2.3 and 2.4.7 of the Final Safety Analysis Report.
The following actions will allow TVA to fully address the-issues of inleakage and final dewatering pump status.
Surveys of groundwater inleakage at BFN are being performed on a periodic basis to provide baseline data for estimating inleakage during a PMF.
From the surveys to date, the inleakage into the Reactor Building has been conservatively estimated as not exceeding 3 gpm, even during heavy rainfall periods.
2, Injection grouting of Reactor Building floor and wall cracks began in July 1986 and has been effective in reducing groundwater inleakage.
Additional grouting is being done on an as-needed basis.
TVA plans to resolve the issue of dewatering pump operation by May 1, 1987.
We will keep you informed of the progress in resolving this issue.
If you have any questions, please call M. J.
May at (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY
.u4 J. A. Domer, Assistant Director Nuclear Safety and Licensing cc:
Mr. G.
G. Zech, Director TVA Project.s U.S. Nuclear Regulatory Commission 101 Marietta St NW, Suite 2900 Atlanta, Georgia 30323 Mr. G.
E. Gears U.S. Nuclear Regulatory Commission Browns Ferry Project Manager 7920 Norfolk Avenue
- Bethesda, Maryland 20814 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 2, P.O.
Box 311
- Athens, Alabama 35611
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