ML20105B721
| ML20105B721 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/11/1992 |
| From: | William Cahill, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-92 CP-92-13, TXX-92417, NUDOCS 9209210126 | |
| Download: ML20105B721 (3) | |
Text
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""*""" C Log (i TX.X-92417 file # 10111 Ref. # 10CFR50.56te) 11][I ll IfW September 11, 1992
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,.l. Cahill, Jr.
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5 Nuclear Pequl ator y Commission Attn: Document Contr01 D e 'd Washington, l'C 20065 StIDJ E C T :
C0HANCHE PE AK STEAM ELECTRIC STATION (CPSES)
DOLKE1 NOS. 50-446 AND 50 446 EDG LUBt Olt FPE!' PE REGULATING VALVES SDAk Cp-92-13
( F 4..si R[ POR1 )
Gentlemen:
On August 12 1992 via fu simile. 10 Elettric notified the NRC of a reportable detect in the CPSES Unit ? T rain ' A' diesel generator lube oil pressure regulatinq valves.
However. f urther evaluation has deter mined that the deviation is not reportable pursuant to 10CfRLO.55(e) or 10CIR21.
At t ac hed is t he written report which satisfies the reporting requirements of 10C f R50. 55( e ).
The report has been formatted in en manner that corresponds to t he specific information requestod by subparts (i) through (viii) of pa ra g ra ph 10C F R'0. 55( e )( 8 ) of the r egul at ion.
This is exclusive of that portion of subpart (viii) regarding the advice that hos been or will be given to other entities ou'-ide of TO Elect ric.
Such advice would be dependent on the entities' specific use and operating / maintenance history of the subject components.
Sincerely, r>f William J. Cahill, Jr.
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Roger D. Walter Manager of Regulatory Affairs for NEO CEJ/qrp Attachment c
Mr. J.
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Milhoan, Region IV Resident inspectors, CPSES (2)
Mr. B. E. Holian. NRR Mr. T.
A, Bergman, NRR i
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i Attachment to IXX-92417 Page 1 of 2 10CFR50.55(E) REPORTABLE DEFECT INVOLVING THE DIESEL GENERATOR LUBE OIL PRESSURE REGULATING VALVES (1)
Information supplied by:
William J. Cahill, Jr.
TV Electric 400 North 01ive Street. L.B. 81
- Dallas, Texas 75201 (ii)
The basic component is the CPSES Unit 2 Train *A* emergency diesel generator lobe oil pressure regulating valves (EDG).
l (111)
The EDG 3as supplied by Delaval Engine A Co sressor Division for Cooper Energy Services.
(iv)
Bore clearances in the lube oil pressure regulating valves were smaller than required, causing the valves to stic6 open.
This could-cause excessive bypass flow back to the EDG lube oil sump, i
This issue was first identified during the 1985-86 time frame.
Cooper Energy Services sent a Product improvement Matrix to users describing a product change involving a new sleeve, an increase of housing to-sleeve and sleeve-to-sleeve clearances, and a longer dif f erential pressure spring, The Unit 2 valves were returned to the vendor for the modification and reinstalled when received back to CPStS.
When the Train
'A' valves were disassembled in August 1992, it was noted that the machining portion of the modification described in the Matrix had not becn performed.
During diesel testing, the auxiliary lube oil pump is started first to build up lube oil pressure before the engine rolls.
As the engine begins to roll, the combined discharge pressure f rom both the auxiliary and shaf t-driven lube oil pumps forces the regulating valves to open fully.
As the oil pressure stabilizes, the auxiliary I
pump is stcured.
If the valves were to stick in the full-open position at 'ihis point, the header and turbocharger oil pressure would decrease to a point near the -low lube oil pressure trip.
This trip is designed to protect the diesel-during testing only.
The auxiliary lube oil pump is not started during an emergency diesel start and the low lube oil pressure trip is deactivated to allow the diesel to remain in amergency i
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.uting e pefience with the valve < in t he f 011 t i e n po'. i t i en shows Ihat tho nii pre".nure Lt oliil i zes fiea t t he 1 ow pf e',sur e tfin Letpoint end adequate lute oil h a '.
till heen topplied t o t he angine.
Therefore, t his deviat inn doe < not r ep r e <.en t a defect which could treate a substantial safety hazard and i' not reportable pursuant to 10 C f P!,0. % ( e ) or 10CIRT1.
(v)
Thit devintlen was identified on J une l'6.
1992.
(vi)
Thete ore two diesel generator 5 per Unit at CPSLS,
<vii>
The pressure reaulating valve < ha ve treen removed, machined to the v e n d o r ' r, r ec ommended c l ea r anc e s, reinstalled, and tested
$dtisfdC1orily.
(viii) This deviation is applic able t o C P5[S Uni t 1.
i wever, the lobe oil p r e ' s. u r e r egul a t i n<1 valvee i >; r tiot h Uni t I diesel generators and the Unit c train
'B' diesel aenerator previout.ly were modified by the verelne and have all operated without stickin'] since then.
1herefore, no f ur t her ac tino it required.
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