ML20029A663

Requests Waiver of Compliance W/Requirements of Tech Specs Table 4.8-1 Re Diesel Generator Testing Frequency

ML20029A663
Person / Time
Site:	Vogtle
Issue date:	02/26/1991
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-02400, ELV-2400, NUDOCS 9103010152
Download: ML20029A663 (3)

Text

_ . . _ .. . ~ _ .._.- - . .- _.. . - . - - - .. . ~ . . . . . -

.c- .g j Geo"fa Power Company 333 Pmomont A4mm E ;a - A!unta Geoq 4 30308

,'- - b:ephyw 404 GN3196 h*3 Stg Addren

$8CNsY*

Dw@m Ahma JTM

. . Whene N5 t@ 05M Tebruary 26, 1991 ,, , m

~

WI GI Natraton,111 r e o,v ce n e v;e m New Owems ELV-02400 0783 Docket No.-- 50-425 U. S.' Nuclear Regulatory Commission ATTN:. Document Control Desk ,

Washington, D. C. 20555

- Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT REGIONAL WAIVER OF COMPLIANCE

. DIESEL GENERATOR TESTING FRE0VENCY This letter requests a one-time-waiver of compliance with the requirements of Technical = Specification Table 4.8-1 as applied to Vogtle Electric Generating Plant-'(VEGP) Unit 2 Diesel Generator (DG) 2A only. Tabic 4.8-1 provides the .

criteria _for determining _the-frequency of DG testing, iThe normal- frequency of testing'is. once per 31 days. If a DG has experienced 2

.or-more-failures in the last 20 valid tests or 5 or more failures in the 1ast.

7 100 valid tests, the frequency of testing is increased to once per 7 days in u accordance with Table 4.8-1. The table contains a footnote that provides for-E - returning to the normal-test schedule following 7 consecutive successful starts,-

o provided the number of: failures in the previous 20 tests.is 1 or less. However, this footnotefis only applit.d to the' increased testing frequency 'as a result of-

- reaching-the.2 out of 20 criterion.-

Georgi _a Power. Company (GPC) letter ELV-01995' dated August 7, 1990, provided a

- specialtreport.of valid DG failures. The-failures. described in that report were attributed to inadequate manufacturing tolerances that could;cause. starting' air valve pistons to " stick" in their cap assemblies.-.A separate report in L accordance with-10 CFR 21 was submitted to the NRC by the manufacturer.1 This issue was-identified as the-cause of 4 separate, valid failures of DG2A which occurred on 1-24-90, 1-25-90,o4-12-90, and 7-11-90.- Letter ELV-01995 also noted ,

that-this- resulted in a total of 5 valid failures *in'43 valid tests of:DG2t..-

- Asia result.of theseLfailures and in accordance:with-Technical Specification 4.8-1=,-'the test frequency-of DG2A was increased to:once per 7_ days.

- Since DG2A

-had received less than 100 valid tests, Table 4.8-1 res' ulted in a requirement--

lfor- wee'kly- testing for Lan extended period of time. As of January 22,=1991, DG2A" required an additional-_46 successful valid tests without a failure before i satisfying the' requirement for 100 valid tests with less than 5 valid failures.

1 3R0n90 9103010152 910226 M di PDR ADOCK 05000425 }I

-P PDR -

0 .

-= . .

(

• s i

)

Georgia Power b U. S. Nuclear Regulatory Commission ELV-02400 Page 2 Since the manufacturing tolerance issue was identified as the cause of 4 of the DG2A failures and has been corrected, and because the DG has had at least 7 consecutive successful tests with 1 or less failures out of the last 20 tests, GPC has concluded that it would be appropriate to return to the normal testing frequency for DG2A, This is consistent with Enclosure 1 of NRC Generic Letter 84-15 which seeks to minimize unnecessary DG testing and states, "...the staff has concluded that the frequency of fast start tests from ambient conditions of diesel generators should be reduced" and "The staff has concluded that excessive testing results in degradation of diesel engines."

Georgia Power Company requests that the NRC grant a one-time Regional Waiver of Compliance with the Technical Specifications, as applied to DG2A, by allowing the DG failures associated with the manufacturing tolerance issue to be counted as only 1 failure occurring on 1-24-90, for the purpose of applying the requirements of Technical Specification Table 4.8-1.

This is a one-time request and does not require a permanent Technical Specification revision. The Plant Review Board (PRB) has reviewed this request and concurs with it. Only the frequency of DG testing is affected by this waiver. Diesel generator reliability has been adequately demonstrated by the completion of 29 consecutive, valid tests between 7-11-90 and 1-22-91 without a valid failure. The Technical Specification waiver will prevent excessive DG testing that does not increase DG reliability.

Another valid failure of Diesel Generator 2A occurred on 1-29-91 when the DG was tied to the grid. Investigation has not determined a definitive cause for this failure,-and further testing has been unable to repeat the failure. Initially, l high resistance across the contacts of the voltage regulating bridge circuit transfer relay was thought to be the cause of the event. However, it has since been determined that this could not have been the cause and our investigation of this event continues. Nevertheless, this failure is unrelated to the previous problem with the manufacturing tolerances of the cap assemblies. A separate report concerning this event will be submitted to the NRC by February 28, 1991.

This waiver of compliance will not affect the probability or consequences of accidents previously analyzed, and it will not introduce the possibility of a new or different type of accident becausa only the DG test frequency is affected. Since the cause of the previous failures has been identified and corrected, the margin of safety provided by the Technical Specification is not I

affected. Based on these reasons, GPC has concluded that this waiver of compliance does not involve any significant hazards considerations as described .

by 10 CFR 50.92 (c). Since this waiver only affects the frequency of DG testing, it does not involve any irreversible environmental consequences.

Sincerely, ht W. G. Hairsto , III WGH,III/HWM/gm (xc see next page)

. . . . _ _ . ~ . _ _ __.._.. _ ._.__.._ _.___ _.. _ . _ ._ . _ _ _ . _ __ . _ _ . . _

+ x

6 ,

.a Geo,rtjiaPower *I

U.sS. Nuclear Regulatory Commission ELV-02400-

-Page:3'

~

xc: lGeoraia Power Company

. :Mr. C. K. McCoy Mr. W. B. Shi> man 1 Mr. P. D. Rusiton Mr. R. M. Odom-NORMS r

U. S. Nuclear Reaulatory Commission Mr.'S. D. Ebneter,-Regional = Administrator Mr. D.

S Hood, Licensing Project Manager, NRR

e - Mr. B. R. Bonser, Senior Resident Inspector, Vogtle

.}.',-

.- g -

2 p t

.r\.

c i

k 1 I

+

--f"r

)

s -'h

$:'- t' f$ $ ,

'y ';; llI 1

i

,,:,i- - :- ,

i:

,. ...a<. .-, 6 .. . . . . - - . . . . . . . . . . , . . _ _ - . . . ,

1.-. ... ,, -.-~ ,, . f