ML20044F958

License Change Request 93-08 to License NPF-57,changing TS to Increase Voltage Limit When Performing 18-month full-load Rejection Test for EDGs

ML20044F958
Person / Time
Site:	Hope Creek
Issue date:	05/21/1993
From:	Hagan J Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20044F959	List: ML20044F958 ML20044F960
References
NLR-N93061, NUDOCS 9306010260
Download: ML20044F958 (7)

Text

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s Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Nuclear Department MAY 211993 NLR-N93061 LCR 93-08 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen:

LICENSE AMENDMENT APPLICATION INCREASED VOLTAGE LIMIT FOR LOAD REJECTION TEST FACILITY OPERATING LICENSE NPF-57 HOPE CREEK GENERATING STATION DOCKET NO. 50-354 This letter submits an application for amendment to Appendix A of Facility Operating License NPF-57 for the Hope Creek Generating Station and is being filed in accordance with 10CFR50.90. This amendment request would increase the voltage limit when performing the 18-month full load rejection test for the emergency diesel generators.

A description of the requested amendment, supporting information and analyses for the change,'and the basis for a no significant hazards consideration determination are provided in-Attachment 1.

The Technical Specification pages affected'by-the proposed change are marked-up in Attachment 2.

Pursuant to the requirements of 10CFR50.91(b) (10) , PSE&G has provided a copy of this amendment request to the State.of New Jersey.

Upon NRC approval of this proposed change, PSE&G requests that the amendment be made effective on the date of issuance, but implemented upon restart following the fifth refueling. outage.

This provides sufficient time for associated administrative activities and for necessary outage testing.-

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MAY 211 993 Document Control Desk NLR-N93061 PSE&G would be pleased to discuss any questions or additional information that you might have regarding this request.

Sincerel',

J J. H ga Vice P esi ent -

Nuclear erations Attachments (2)

C Mr. Stephen Dembek Licensing Project Manager Mr. T. P. Johnson Senior Resident Inspector Mr. T. Martin, Administrator Region I Mr. Kent Tosch, Chief New Jersey Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625

REF: NLR-N93061 LCR 93-08 STATE OF NEW JERSEY )

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COUNTY OF SALEM )

J. J. Hagan, being duly sworn according to law deposes and says:

I am Vice President - Nuclear Operations of Public St.aice Electric and Gas Company, and as such, I find the matters set forth in the above referenced letter, concerning the Hope Creek Generating Station, are true to the best of my knowledge, information and belief.

Subscribed and Sworn to before me this 8/,,/ day of Y)7d(1 , 1993 J

l sT1 11 A A D 1 1 OLLA Motary Publ'c i h New Jersey KIMBERLY JO BROWN ,

NOTARY PtlBLIC OF flew JERSEY My Commission Empires April 21,1998  :

My Commission expires on  !

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ATTACHMENT 1 ..

PROPOSED CHANGE TO THE TECHNICAL SPECIFICATIONS' INCREASED VOLTAGE LIMIT FOR LOAD REJECTION TEST FACILITY OPERATIONS LICENSE NPF-57 HOPE CREEK GENERATING STATION DOCKET NO. 50-354 NLR-N93061 LCR 93-08 I. DESCRIPTION OF THE CHANGE p l

PSE&G requests that surveillance requirement 4.8.1.1.2.h.3 be revised to increase the voltage limit to 4785 volts when  !

performing the 18 month diesel full load rejection test. The

'##' and corresponding footnote applicable to section 4.8.1.1.2.h is also to be deleted by this change request. A marked-up copy of the Technical Specification (TS) page is included in Attachment 2.

II. REASON FOR THE CHANGE The current TS limits the maximum voltage when performing the continuous rating load rejection test on the diesel generators to 4580 volts both during and after the test. This value does not i adequately account for high reactive loading that the generators might experience nor the transient type test conditions that exist; either of which, can result in unnecessarily declaring the diesel inoperable for failure to meet this limiting value. As a '

result, there exists the potential for increased diesel operation of the non-affected diesels (to conform to the actions of the LCO) and also the affected diesel (to re-run the test).  ;

The '##' and corresponding footnote for TS 4.8.1.1.2.h pertained-to a one tino extension for surveillance interval on 1AG400 and ,

IDG400 Emergency Diesel Generators. This exemption is no longer applicable since it expired on October 15, 1989 and is,

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therefore, being deleted from the Technical Specifications. [

III. JUSTIFICATION FOR THE CHANGE The TS Bases state that the surveillance requirements for  !

demonstrating the operability of the diesel generators are in accordance with the recommendations of Regulatory Guide 1.9,

" Selection of Diesel Generator Set Capacity for Standby Power Supplies", March 10, 1971, and Regulatory Guide 1.108, " Periodic Testing of Diesel Generator Units Used as Onsite Electric Power i Systems at Nuclear Power Plants", Revision 1, August 1977.

Although Regulatory Guide 1.137, " Fuel-Oil Systems for Standby

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Diesel Generators", Revision 1, October 1979, is also used to ';

demonstrate operability, it does not involve load rejection testing. The referenced documents require that the diesel generators be capable of a complete loss of load without exceeding speeds or voltages which will cause tripping. Though criteria is provided for determining speed requirements, there does not exist similar criteria for voltage on the full load rejection test.

Hope Creek diesel generators do not have a high voltage trip.

The current maximum voltage limit of 4580 volts is 10% above the nominal value of 4160 volts. This is also the value for the upper voltage acceptability limit during steady state testing.

To impart this same criteria for transi'nt conditions is excessively restrictive. In fact, Generic Letter 84-15,

" Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability" provides a value that is 15% above the nominal voltage of 4160 volts, (4785 volts), when performing a continous rated load rejection. Fifteen percent is consistent with the limits imposed on engine speed by the previously listed Reg.

Guides when performing a full load rejection. The NRC cited example of 4785 volts is the value that is proposed in this license change.

10CFR50.92 SIGNIFICANT HAZARDS CONSIDERATION ANALYSIS PSE&G has pursuant to 10CFR50.92, reviewed the proposed amendment to determine whether our request involves a significant hazards consideration. We have determined that: ,

The operation of Hope Creek Generatina Station (HCGS) in accordance with the proposed chance vill not involve a sinnificant_ increase in the probability or consecuences of an accident oreviously evaluated.

The proposed change affects a surveillance requirement of the diesel generators which is performed along with various other i tests to demonstrate operability. The operability of the diesel generators ensures that sufficient power.will be available to supply the safety related equipment required for the safe shutdown of the facility and the mitigation and control of accident conditions within the facility during power operation.

The operability during shutdown and refueling ensures that the facility can be maintained in the shutdown or refueling condition for extended time periods and ensures sufficient instrumentation and control capability is available for monitoring and maintaining the unit status.

The purposes for diesel generator operability as described above do not involve the probability of accidents that are already evaluated, but rather the diesel gene' ' ors can impact the consequences of an accident (e.g. if use were to fail) . This change, however, does not affect the diesels' ability to mitigate ,

an accident nor does it affect its operability.

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The purpose of performing a full load rejection test is to demonstrate that the engine will remain available (i.e., will not trip) if for some reason the generator output breaker were to open with the engine carrying all the design safety loads-or for some other event that would cause a simultaneous loss of all loads. If this rejection were to occur, closing the output breaker and reloading the generator as quickly as possible would be desirable. Since there is no trip involved with a high voltage condition that might be experienced on a load rejection, the reason for having such a criteria is to demonstrate that the voltage regulator is capable of maintaining the generator stable.

The second parameter used as an acceptance criteria to demonstrate stability on a load rejection is engine speed. This tests the operation of the governor and the ability to adequately maintain engine control. Though 115% of nominal speed is given in the Committed Regulatory Guides as the acceptance criteria, engine speed is independent of voltage and is not part of this LCR.

The change being performed increases the acceptable voltage by 5%

(205 volts) that the generator might experience on a loss of full load. Thus, the total acceptable value would be 15% (625 volts) over the nominal rating of 4160 volts. There is no detrimental effectc on the generator if 4785 volts would be experienced.

During ti.e initial manufacturer's acceptance test, a high-pot on the generator was performed with a voltage of 1.5 times the nominal rating (6240 volts) applied to the unit. On the load rejection, the subsequent increase in voltage is a momentary spike as the voltage regulator will return the voltage to a lower steady state unloaded value. Operating the generator with a high voltage would have an effect on the loads being supplied.

However, this does not need to be evaluated since at the time the voltage spike would be experienced there would be no loads connected to the diesel generator. Only the generator would experience the increase in voltage and not the associated loads.

The effect of this slight increase in voltage would have a negligible.effect on the machine. The windings are able to withstand voltage values that are substantially higher. The point at which the insulation and connections break down (e.g.

BIL value) are also substantially higher.

It can therefore be concluded that the increased voltr,ge value on which the testing acceptance is based will not have an effect on the diesel generator operability. Since operability of the diesels is not effected, there is no increase in the consequences of an accident previously evaluated.

The operation of Hone Creek Generatina Station (HCGS) in accordance with the proposed chance will not create the possibility of a new or different kind of accident from any previously evaluated.

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The proposed change involves an increase in the upper limit for a test acceptance criteria. -There are no physical changes that are to be performed to the plant as a result of this change to the Technical Specifications nor is there a change to the manner in which the plant is operated. As discussed above, this new value does not affect the operability of the diesel generators.

Therefore, no new or different kind of accident is created by this change.

The operation of Hope Creek Generatina Station (HCGS) in ,

accordance with the Droposed chance does not involve a  ;

sinnificant reduction in a naruin of safety.

The change does not affect the diesel generators' ability to mitigate the consequences of any loss of power accident.

Allowing the generator an additional 205 volts increase for a loss of continuous rated load does not affect the ability to recover from the anticipated transient. All design requirements and parameters of the emergency diesel generators will be maintained. It concluded that this change does not involve a significant reduction in safety margin.

Conclusion:

Based upon the above, PSE&G has determined that this proposed change does not involve a significant hazard.

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