ML20004F158
| ML20004F158 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/22/1981 |
| From: | Curran J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IAL, NUDOCS 8106160567 | |
| Download: ML20004F158 (2) | |
Text
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Southern California Edison Company 5$'l-Sae' ONOPRE NUCLE AR GENE R ATING ST ATION S AN C LEssaEN T E, C A kt ORNIA,2472 9FNED "IMMEDIATE ACTION LETTER REPLY" JUtl 1 1931 '_-
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May 22,1981
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U. S. t'uclear Regulatory Commission Office of Inspection and Enforcement Region V s
1990 North Califor.nia Boulevard d b'
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Attention: tir. R. H. Engelken, Director V
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DOCKET Mo. 50-206 SAN ONOFPE - UNIT 1 c
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Dear Sir:
FOREIGH l'ATERI AL ret:0 VAL FRCt1 -
REACTOR COOLANT SYSTEf1
Reference:
1)
Letter dated 10/15/80 from R. H. Engelken to L. T. Papay, Subiect: Steam Generator Repairs at San Onofre Unit 1 2)
Letter dated 1/27/81 from J. L. Crews to L. T. Papay,
Subject:
HRC Inspection (12/1/A0 - 12/24/80) San Onofre Unit i 1
As a result of the discovery of fonign naterial in one loop of the reactor coolant system in October of 1980, reference (1) requested that we subnit to you a repoit covering the analysis of the possible effects of any foreign material which has entered the orimary system and not been retrieved.
This letter provides you with the requested infonnation.
Since the initial discovery of foreign material in the hot leg of reactor coolant system loop "A", a thorough inspection of ecch hot leo and All cold (intemediate) leg of the reactor coolant systam has been conducted.
foreign objects discovered have been renoved intacc. This naterial was discovered, as expected, in the bottom of the pipe elbows adjacent to the stean generators.
Inspection of the reactor vessel or other conponents of the reactor coolant system for foreign material is considered to be unwarranted and none is planned.
sta 6'{1 si o 'esS7 a
U. S. Nuc1 car Pzgulatory Comission Page # 2 Concurrent with the above inspection and foreign object removal, all large deposits of magnetite (Fe3 4) which entered the primary system loops 0
during the steam generator channel head decontamination process were removed.
As expected, all magnetite which entered the loops had dropped out of suspension in the imediate vicinity of the pipe elbows near each steam generator nozzle, enhancing retrieval efforts. Small amounts 'of magnetite grit from the steam generator channel head decontamination process may, however, remain in the primary system.
Magnetite is a normal corrosion product in any reactor coolant system.
The build-up of such corrosion products was considered in the design of the plant, and therefore, represents no new deleterious material to the reactor coolant system.
Nevertheless, prior to return to power, further actions will' be taken to renove residual magnetite. Specifically, the reactor coolant will be processed through a demineralizer and filter bank until particulate limits are met.
Peference 2 contained a commitment to detcrmine the amount, and effect of aluminum released to the reactor coolant as a result of corrosion of an aluminum steam generator nozzle seal cover that was inadvertently dropped into reactor coolant system cold (intemediate) leg "A".
This cover was recovered intact by renote means on 1/17/81 after being imersed for approximately 12 weeks. Coolant samples removed fron the intermediate leg yielded aluminum concentrations of approximately 150 ppb.
Since removing the nozzle cover, the cold (intemediate) leg of loop "A" has been drained and refilled from the PCS. Coolant sanples taken from the intemediate leg after refilling have yielded aluminum concentrations less than 20 pph, which is less than the maximum permissable concentration.
To remove any non-dissolved aluminum, flushing of the intermediate leg
- was perfomed while the loop was being drained. Further actions to remove any residual aluminum will be perfomed in conjunction with the residual magnetite removal.
To preclude the entry of additional foreign material entry into the primary system, seals have been placed in each steam generator nozzle. These seals have been and will continue to be inspected once per shift while work continues on the steam generator repair project.
If seals are removed or require repair prior to completion of the steam generator repair project, such removal and/or repair wili be documented, and the potential for foreign material entry will be evaluated and appropriate corrective actions taken.
If you have any questions or desire further infomation concerning this matter, please contact me.
- incerely, J. M. Curran plant Fanager Jf1J:FB:dh:6aU cc:
L. F. Miller (!!PC Site Inspector - San Nofre Unit 1)
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