NLS8700542, Application for Amend to License DPR-46,changing Insp Interval for Diesel Generators to Conform W/Mfg Recommendations.Evaluation of Change Encl.Fee Paid

Application for Amend to License DPR-46,changing Insp Interval for Diesel Generators to Conform W/Mfg Recommendations.Evaluation of Change Encl.Fee Paid

ML20236F932
Person / Time
Site:	Cooper
Issue date:	10/20/1987
From:	Kuncl L NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20236F935	List: ML20236F941 NLS8700542, Application for Amend to License DPR-46,changing Insp Interval for Diesel Generators to Conform W/Mfg Recommendations.Evaluation of Change Encl.Fee Paid
References
NLS8700542, NUDOCS 8711020344
Download: ML20236F932 (6)

Text

T' '

?

l

- I ar* i

h*N\.u- Nebraska Public Power District -.

" ~ * "%$hdh ffbAM*** *"

NLS8700542'. i

' October 20, ~ 1987 -- ) i i

U.S.' Nuclear Regulatory Commission i

Document Control Desk Washington, DC 20555 i Gentlemen:

Subject:

Proposed ' Change No. 27 to Technical Specifications Diesel Generator Testing y Cooper Nuclear Station NRC Docket No. 50-298, DPR-46 _

In accordance with the applicable provisions specified in 10CFR50, Nebraska Public Power District requests that the Technical Specifications for Cooper Nuclear Station (CNS) be revised to change the inspection interval for the Diesel Generators to conform with the manufacturer's recommendations.

- An evaluation of the proposed change with respect to the requirements of 10CFR50.92 and the applicable revised Technical Specification page are contained in the attachment. i 4

-This proposed change incorporates all amendments to the CNS Facility Operating j License through Amendment ~ 111. issued September 17, 1987. By copy of this i letter and attachments, the appropriate State of Nebraska Official is being notified in accordance with 10CFR50.91(b). i This change has been reviewed by <the necessary Safety Review Committees and payment of $150 is submittedein accordance with 10CFR170.12. l In additice3tWtXree signed originals, 37 copies are also submitted for your ]

usea;/44HT3 you' have any questions or require additional information, please contact me.

Sinc ely, 8711020344 871020 3 PDR ADOCK 03000298 1 p PDR ,

- L. G. Ku cl i Vice-President - Nuclear I

LGK/mtb:mh23/5 l H  !

0 cc: H. R. Borchert \ bg}i Department of Health d\-(4 ,

I State of Nebraska 0k $ gD 'g i NRC Regional Office k0 Region IV \ \\$q Arlington, TX l- NRC Resident Inspector Office Cooper Nuclear Station  ;

o E {

STATE OF NEBRASKA)

PLATTE COUNTY )

L. G. Kuncl,. being first duly sworn, deposes and says that he is an  !

authorized representative of the Nebraska Public Power District, a public corporation and political subdivision of the State of Nebraska; that he is duly authorized to submit this request on behalf of Nebraska Public Power District; and that- the statements contained herein are true to the best of his knowledge and beli.ef.

t U. G. Kuncl Subscribed in my presence and sworn to before me this d day of.

(OofMa] , 1987.

Odooa) 77L k$dl NOTARY PUBVIC /

seERALummen etinnen COLLEEN M. KUTA Nr Cas a E 4 Aug 4,1980 I

l l

l

Revised Technical Specifications for Diesel Generator Inspection Interval Revised Page: 194 Cooper Nuclear Station (CNS) Technical Specification 4.9.A.2.f requires each diesel generator be given an annual inspection in accordance with instructions based on the manufacturer's recommendations. Cooper-Bessemer, which is the CNS Diesel Generator Manufacturer, recently issued a service news bulletin 1 which stated that the inspection interval could be extended from twelve to eighteen months. Cooper-Bessemer indicated this was done to allow the inspections to coincide with other site activities such as refueling outages.

It is desirable to perform the diesel inspection while the plant is shut down for several reasons. First, the inspection requires some disassembly of the diesel which renders the diesel inoperable. Good engineering practice dictates that it is not wise to intentionally disable a vital emergency power system, while the plant is at power, when there are no signs of problems or malfunctions. The inspection could better be postponed until the next shutdown of sufficient duration rather than conducting it while the plant is ..

at power just to meet the surveillance frequency requirement. In light of the diesel manufacturer's conclusion that extending the inspection interval to 18 months has no negative impact on the diesel, extending the interval is prudent.  !

l Also, the diesel inspection takes approximately one week to coinplete. The current Technical Specification Limiting Condition for. Operation (LCO) allows l the plant to operate for seven days with one diesel inoperable. If the diesel )

inspection is conducted at power, the plant has to intentionally enter a l There is a high likelihood that the inspection could take seven day LCO.

longer than seven days, which would exceed the LCO requiring the plant to shut down.

The District believes that changing Technical Specification 4.9. A.2.f to reflect Cooper-Bessemer's recommendation to allow up to an 18-month inspection interval will provide - greater operational flexibility to conduct the diesel l inspections durin6 shutdowns. Accordingly, Nebraska Public Power District I requests a revision to Technical Specification 4.9.A.2.f to allow the inspection conducted in accordance with the manufacturer's recommendations to be performed at least once every 18 months during shutdown.

This revision will make the CNS Technical Specifications consistent with GE Standard Technical Specification 4.8.1.1.2.e.l.

1 I

l j

j Evaluation of this Revision with Respect,to 10CFR50.92 l l

A. The enclosed Technical Specification change is judged to invSive no 1 significant hazards ba' sed on the following: )

I Does the proposed license amendment involvs a significant increase I 1.

in the probability or consequences of en accident previously i evaluated? l Evaluation: ,

The proposed amendment extends the allowed diesel generator inspection interval from every 12 months to every 18 months, during (

shutdown. The availability, performance, and reliability of the {;

diesel generators is essential to the plant response to the design basis loss of-coolant accident and concurrent loss of off-site power- I analyzed in Chapter 14 of the Updated Safety Analysis Report. The two 4160 volt diesel generators provide the standby source of AC power. As the on-site source of AC power, each diesel is capable of 1 providing power to the emergency service portions of the auxiliary power system. Thus, each diesel is capable of performing the i required safety function for standby AC power, which is to shut down )

the plant and maintain it in a safe shutdown condition following loss of off-site power.

The District has concluded thst the change from a 12-month surveillance interval to an 18-month interval, during shutdown, will not degrade diesel generator availability, reliability or performance. This conclusion is based on the following:

1

1) The diesel vendor has evaluated the maintenance, testing, and '

j operational practices for the diesel service at Cooper Nuclear Station (CNS). The vendor concluded that diesel reliability and performance will not be deBraded ' by increasing the surveillance interval to 18 months.

2) The NRC approved Standard Technical Specification' Surveillance Requirement 4.8.1.1.2.e.1 states: "At least once per 18 months, during shutdown, . . .subj ecting the diesel to an inspection in accordance with procedures prepared in  !

conjunction with the manufacturer's recommendation. . . "

3) The 18 month surveillance interval will provide the flexibility to schedule diesel inspections to coincide with

, plant outages. This will eliminate the need to perform the diesel inspection while the plart is operating, to meet the 12-month surveillance requirement. CNS will not be required to make one of the diesels inoperable to perform the inspection while the plant is running, even without any signs of diesel malfunction. This will improve the availability of the diesels during pla.0 operation, since it will not be necessary to intentionally make one inoperable. This improves reliability in that both of the redundant diesels will be available to perform the' required safety function, in the event of a design basis accident.

2-

i, 1

l Based on the above, the change from a 12-month surveillance interval to .every 18 months,. during shutdown, does not reduce the-availability, reliability or performance of the diesel generators.

Therefore, the. diesels will continue to provide a reliable source of on-site standby AC power. Also, the change in surveillance interval does , not affect the ability of the diesels to supply AC power to ,

shut. down the plant and maintain it in a safe shut down condition following loss-of-offsite power. Thus, this change does not i increase the probability or consequences of any accident yev!ously evaluated.

2. Doe.s the proposed license amendment create the possibility for a new or . different kind of accident from any accident previously evaluated?

Evaluation:

The change from a 12-month to an 18-month interval (during shutdown) does not create any new or different kind of accident. The purpose of the diesel generators is to provide standby AC power to shut down the plant and maintain it shut down following a loss-of-offsite power occurring simultaneously with a design basis accident.

Chapter 14 of the USAR analyzes the design basis LOCA with a  !

concurrent loss-of offsite power. The purpose of the 'subj ect j inspection is to perform certain internal inspections and tests to determine any degradation of the diesel not apparent during normal j service. The only possible affect from changing the inspection  !

interval is an undetected degradation of the diesel which could  ;

affect diesel reliability and performance. However, as discussed ,

above, the increased inspection interval has been determined not to l degrade diesel reliability or performance. This change does not affect the ability of the diesels to perform their intended function in mitigating the consequences of any accident involving a loss-of offsite power. Therefore, no new or different kind of j

\ accident is created. J l

I

3. Does the proposed amendment involve-a significant reduction in a i margin of safety?

The change from a 12 month inspection interval to every 18 months, j during shutdown, allows an additional six monchs of diesel service between inspections. This additional service could be considered to {

be a decrease in the margin of safety, with respect to the reliability of the diesels. However, the diesel vendor has concluded that the increased inspection interval does not degrade diesel reliability for this class of service. Also, the Standard Technical Specifications indicate that an 18-month inspection interval, during shutdowns, is acceptable. While the increased inspection interval could be considered a slight reduction in the margin of safety, the 18-month interval is clearly within the acceptable criteria. Further, the 18-month interval provides the flexibility to conduct the inspections during plant outages. This eliminates the need to either make one diesel j inoperable intentionally during plant operation or to unnecessarily

- _ _ _ _ _ _ ~

.?, n g - i

[g I i- shut down - the ' plant. Eliminating' the inspections during plant -

operation. eliminates the situation-where the. plant is ' operating .in'. -

anL intentional Limiting Condition for : Operation, with : one diesel

. inoperable, .' Conducting future inspections during' shutdowns clearly-increasesi the . margin of safety. . Based on the above,7this change does not. involve ~a significant reduction in a margin of safety.

.e B. ' Additional ~ basisy for- proposed no significant ' hazards consideration.

determination:

, The Commission. has provided guidance concerning' the application. of the ~

J standards for determining whether a significant . hazards consideration T -exists by providing certain examples (48CFR14870).. The examples include:

~

"(vi) a change which. . .may reduce. in ' son - way a safety margin, but where ',

the'results offthe: change'are clearly within'all acceptable.. criteria..." '

The fincrease to an month .Linspection, . during shutdown, . is clearly - .

acceptable since.this is the' Standard.. Technical Specification criteria.

j Se

)-

a 4

.h i

4 c9

)1^

l -

i

. . - r.

s 1 L' . _ _ _ - _ _ _ - _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _

,