ML19290A480
| ML19290A480 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/01/1973 |
| From: | Jennifer Davis US ATOMIC ENERGY COMMISSION (AEC) |
| To: | John Miller METROPOLITAN EDISON CO. |
| Shared Package | |
| ML19250C101 | List: |
| References | |
| NUDOCS 7911070654 | |
| Download: ML19290A480 (1) | |
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NOV 1 1973 s
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- !etropolitan Edison Company Docket :io. 5-23?
ATT:. :
.:r. J. 3. i; iller
'/ ice ')rosid;n t P. O. Box 512 Reading, Pennsylvania 19503 2entlemen:
Thank you for your letter dated September 13, 1973, which forwarded a report pursuant to 10 CFP. 50.53(e).
Y3ur report will be r2vi3wed anJ evaluatid ar.d, should we reqiire additional infornation concern-ing this uatter, we will contact y3u.
Your cooperation cencerning this matter is appreciated.
Sincerely,
/f John G. Davis, Deputy Director for Field Operations Directorate of 'iequlatory Oceratiens bec with copy of 9/18 ltr:
J. P. O'Reilly, R0:1 R0 Files PDR LPDR NSIC 1557 355 RO:FS&EB R0:FSSES:C RO:DDF0 I
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b Dr. D. F. Knuth, Director Directorate of Regulatory Operations Office of Regulation C. S. Atemic Energy Commission Washington, D. C.
20545
Subject:
Three Mile Island Nuclear Station Unit 1 Docket No. 50-289 Failure of Stems on Core Flood Valves
Dear Dr. Knuth:
You were notified on August 20, 1973, of a situation which could be considered reportable under 10CFR50.55(e)(1)(iii), " Conditions of Ccnstruction Permits".
This situation relates to failure of stems on core ficcd valves CF-V-1A and CF-V-1B.
DESCRIPTICN OF INCIDENT During checkout for preparation cf pre-operaticr.al testing, core flocd syste: valve CF-V-1A could not be cpened more than 2" by hand.
Valve CF-V-13 could be opened caly about 1/2" by hand. These valves are Walworth 14" 150C:.2 steel pressure seal gate valves equipped with Limitorque SME-4 cperators.
cast CCRRECTIVE ACTICN Valve CF-V-1A was dissassembled for inspection and a vender representa-tive was called to the site for technical consulation.
It was found that the stem nut would not travel more than 5" dcwn the stec.
The diameter of the stem had a gradual increase of about.030" to about 5" frc= the top eausing the thread to be tapered. At this peint the ste= nut wculd bind and prevent further open-ing by hand operation.
On August 15th and 16th stems were replaced for both core ficod talves under the technical supervisien of the valve manufacturer.
The new sters are ASTM-A 36a type 630 17-<.-PH =aterial, solution annealed and aged.
Ecth valves were satisfactorily manually operated at that time.
Subsequer. ly, the valves have been electricall'. cperated satisfactoril:..
1557 356 79110706 @
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Dr. D. F. Knuth EVALUATION Cause of the elongation is suspected to be due to improper operation of the valve in such a manner as to exceed the tensile strength of the 316 stainless steel stem. This problem appears to occur only in fast acting valves which leads to a possible material problem with the stem.
The valve vendor no longer uses 316 stainless steel but now manufactures stems from 17-4 PH for this application.
The original stems were returned to the manufacturer where they are currently being evaluated.
When the results of the manufacturer's evaluation are received, they will be available for your review at the Three Mile Island site.
Very truly yours, f
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J. G. Miller Vice President brh cc:Mr. H. M. Dieckamp Mr. J. P. O'Reilly Mr. W. A. Verrochi 1557 557