ML18283B387
| ML18283B387 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/24/1976 |
| From: | Gilleland J Tennessee Valley Authority |
| To: | Moseley N NRC/RGN-II |
| References | |
| Download: ML18283B387 (3) | |
Text
830 Pover Buildi TENNESSEE VALLEYAUTHORlTY CHATTANOOGA. TENNESSEE 37401 MAY 2 4 1976 Mr Norman C. Moseley, Director Office of Inspection and Enforcement U.So Nuclear Regulatory Commission Region II Suite 818 230 Peachtree
- Street, NMo Atlanta, Georgia 30303
Dear Mro Moseley:
BROMNS FERRY NUCLEAR PLANT UNIT 3 REPORTABLE DEFICIENCY-CLOGGED COOLING MATER LINES TO RHR AND CORE SPRAY PIMP MOTOR BEARING COOLERS Initial report of the subject reportable deficiency was made to Go R, Klingler, NRC-IE, Region II, on April 22,.
- 1976, In compliance vith paragraph 50o55{e) of 10 CFR Part 50, ve submit the enclosed interim report of the deficiency.
A final report vill be submitted when plans to correct this deficiency are completed and approvedo Very truly yours, Assistant Manager og Power Enclosure CC {Enclosure):
Dr. E, Volgenau, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Mashington, DC 20555 An Equal Opportunity Employer
ENCLOSURE BRANS FERRY NtJCIZAR PLANT UNIT 3 CLOGGED COOLING WATER LINES TO RHR AND CORE SPRAY PtBG'fOTOR BEARING COOIZRS DDR 230 INTERIM REPORT On April 22, 1976, an initia1 report vas made by telephone to NRC-OXE Xnspector, G. R. Klingex, by T. W. Barkalow and S. H. hfindel.
The report was made in compliance with 3.0CFR50.55(e).
This is an interim report.
A final report will be submitted. once final plans to correct the deficiency are completed..
Descri tion of Occurrence While conducting preoperationa1 test TVA-4, the actua1 flow rates in the emergency equipment cooling water (EECW) lines to the RHR and.'core spray pump motor bearing coolers were found. to be below those required by the test.
An investigation revea1ed.
these lines to be clogged. with mud. and scale.
The lines involved. had. diameters of either 3/8 inch or 1, inch.
Cause of the Deficienc The EECW system is only used. during tests or when-'equipment it services is operated..
Therefore, the cooling water lines contain stagnant water for long periods of time.
Since the EECÃ source is raw water from Wheeler Reservoir, the stagnation leads to settlement of suspended solids and. clogging in sections of lan s at the lower elevations.
The system does have strainers, but they have been ineffective in dealing with silty water.
Also, a few lines contained. asiastic clams which vere a11 of about the same size.
This ind.icates that they.map be able to grow in the system between flushings with chlorinated water.
l Safet lications 4
The EECW system provides cooling water to the standby diesel generators, RHR and. core spray equipment room environmental coolers, RHR pump seal
- coolers, and. core spray thrust bearing coolers.
Lin s to the latter two coolers were found. to be clogged..
These lines are the smallest lines in the system and., therefore, are the easiest to clog.
Complete plugging of these lines would. prevent cooling water from circulating thxough this part of the system.
However, temperature measurements indicated in the control room verify whether each cooler or heat exchanger in the affected. unit axea is receiving adequate flow of cooling water.
Inadequate flow could, eventually lead. to failure of the core spray pumps and, the RHR pumps..
~ ~ 5
Descri tion of Corrective Action All the check valves in the clogged, sections of the lines were removed.
and. thoroughly cleaned.
The lines were then backflushed through the coolers.
Tests conducted after the lines were reassembled showed.
ac1equate flm in all be one line to a core spray pump motor bearing cooler.
This line willbe disassembled.
and. reflushed. to remove any remaining blockage.
Means Taken to Prevent a Recurrence Final plans to correct this deficiency have yet to be completed.
and.
approved..