Text

Application for Amend to License NPF-39,changing Tech Specs Re Surveillance Testing of Diesel Generators
	ML20154D191
Person / Time
Site:	Limerick
Issue date:	09/09/1988
From:	Bradley E; PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	; Office of Nuclear Reactor Regulation
Shared Package
ML20154D177	List: ML20154D173; ML20154D191; ML20154D201;
References
	NUDOCS 8809150178
	Download: ML20154D191 (54)
	v • d • e

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BEFORE THE !

UNITED STATES NUCLEAR REGULATORY COMMISSION ,

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In the Matter of a !

Docket No. 50-352 PHILADELPHIA ELECTRIC COMPANY - '

l APPLICATION FOR AMENDMENT i

OF :

l FACILITY OPERATING LICENSE l

NPP-39 I i

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f Eugene J. Bradley j 2301 Market Street !

Philadelphia, Pennsylvania 19101 '

l i-Attorney for l Philadelphia Electric Company e i

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o.

BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of :

Docket No. 50-352 PHILADELPHIA ELECTRIC COMPANY :

APPLICATION FOR AMENDMENT OF FACILITY OPERATING LICENSE NPF-39 Philadelphia Electric Company, Licensee under Facility Operating License NPF-39, hereby requests that the Technical Specifications contained in Appendix A to the Operating License be amended as indicated by a har in the margin of the attached pages 3/4 8-1, 3/4 8-la, 3/4 8-2, 3/4 8-3, 3/4 8-4, 3/4 8-5, 3/4 8-6, 3/4 8-7, 3/4 8-7a, 3/4 8-8, 3/4 8-9, and B 3/4 8-1.

The proposed changes to the Technical Specifications are related to the onsite emergency diesel generators (EDGs). The proposed changes will improve the reliability of the emergency diesel generators and reduce the risk from possible station s a blackout. They are in response to Generic Letter 84-15, "Proposed Staff Actions to Improve and Maintain Dienel Generator Reliability" and are consistent with license changen previously approved for the North Anna Power Station, License No. NPP-7 in Amendment No. 48 issued on April 25, 1985 and vendor recommendations.

Discussion The on-site electrical power systems for the Limerick Generating Station are described in Chapter 8 of the FSAR, The class lE portion of the onsite power system for each unit consists of four redundant and independent 4.16-KV distribution systems, with their 440-V load centers and motor control centers, 208/120-V ac power system, 125-V de system and the standby power supplies (diesel generator units). Each 4.16-KV bus is normally fed from either of two offsite power sources, designated as preterred and alternate, connected to the 220-KV and 500-KV substations through dedicated station auxiliary transformers.

One of these two (safeguard) power supply systems is the preferred power source for channels A and C tor Unit 1 and channels B and D for Unit 2. The other safeguard power supply is the preferred power source for channals B and D for Unit 1 and ;

1 channels A and C for Unit 2. The normal preferred power source i to each bus is electrically interlocked with the alternate power source ao that the bus can only be connected to one (Gingle) j power source at any one time. In the event of loss of preferred power to an engineered safeguard bus, an undervoltage relay l

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s a initiates automatic transfer to the alternate power source and starts the diesel generator if the transfer fails. After transfer, if all offsite power sources remain unavailable, the onsite standby power system will power the safeguard buses.

Limerick Generating Station, Unit 1, has four electrical divisions. The emergency power supply for each of these divisions consists of one diesel generator set complete with all necessary auxiliary systems. Each diesel generator is connected to only one 4.16-KV class lE bus. Each diesel generator set is operated independently and is normally discon')ected from the offsite power system, except during testing. Each diesel generator is automatically started by either a LOCA signal or by an emergency bus undervoltage signal from its respective bus and is capable of attaining rated voltage and frequency within 10 seconds after receiving a starting signal. In the event of a LOCA, the elecsrical loads are autcmatically connected to their respective diesel generator, after rated voltage and frequency are attained by the diesel generators, with the loads being connected in a predetermined sequence over an approximate three minute period. j Some of the existing Surveillance testing requirements tor.the EDGs include demonstrating starting capabilities from ambient conditions without specifically designating pre-lubrication or prewarming prior to the test. Further, the existing Technical Specifications stipulate that the EDGs must l

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t demonstrate the ability to connect and carry full electrical load while still cold.

It is this routine Surveillance Testing of the "cold fast start" capability of the diesel generators in 10 seconds without provisions for prelubrication or prewarming, along with the rapid three minute loading, which has caused serious problems in the reliability of diesel generators. The proposed changes !

described below are related to the "cold fast start" testing I requirements and to the relationship between periodic testing and

diesel generator reliability. Other proposed changes include l provisions for completing the 18 month maintenance inspection while at power rather than when sht.tdown.

The Licensee does not propose uny changes to the scitedule or methods for of fsite-to-onsite circuit verification or j

any changes to the periods allowed for recovery from degraded i conditions in the Action Statements.

Generic Letter 84-15 The Commission staff, in Generic Letter, 84-15 discussed the need to assure that the reliability of diesel generators is j i

maintained at an acceptable level, by reducing the number of cold i fast starts for surveillance testing because the cold fast starts cause unnecessary premature diesel engine degradation. The staff i

determined that some testing techniques for diesel generators did i l

I not take into consideration those manufacturer-recommended :

1 preparatory actions such as prelubrication of moving parts and i l ;

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a s

warm-up procedures prior to starting diesel generators. The prelube/ prewarm actions are necessary in order to reduce engine wear, extend diesel generator life, therefore increasing EDG availability. The existing surveillance requirements require fast diesel generator starts from ambient conditions. These "cold fast starts" subject the diesel generators to undue wear and stress on engine parts. The diesel generator vendor recommends gradually accelerating the diesel generators to synchronous speed during testing to prevent stresses resulting from rapid temperature changes during a fast start. Further, the present manner of electrical loading (and unloading) of the ;

, generator also has adverse effects on EDG reliability. Gradual electrical loading decreases the wear and stresses on the diesel engine and on the generator.

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Proposed Routine EDG Test Method I

The proposed routine EDG tests will require the engine to start and automatically accelerate to an initial setting (idle

speed, 300 - 500 rpm). Engine speed will then be manually ;

l increased to synchronous speed over a period of 1 to 2 minutes.

Loading of the EDG will be manually increased in a series of plateaus ratner than a continuous ramp to the required load.

The EDG will be inoperable during the beginning of each j routine test due to the generator excitation being turned off and

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j the governor mechanical speed control setpoint being lowered.

The de-energization of the diesel generator field excitation is annunciated locally with a common trouble alarm being annunciated 1

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in the main control room to alert the operators to the diesel generator's inoperability, per Regulatory Guide 1.47. These periods of inoperability will be minimized by procedural controls. The periods of inoperability will not be used in the J availability calculations since they are associated with tests performed in accordance with vendor's recommendations.

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Limerick EDGs are equipped with lube oil and jacket water keepwarm systems which maintain the lube oil at approximately 125-130 degrees F and the jacket water at 110-115 degrees F. These systems operate whenever the engine is shutdown and are considered to be part of the diesel generator ambient conditions. It is Limerick policy to accept inoperability of an EDG when a keepwarm system does not operate properly and

! necessary temperatures cannot be maintained.

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EDG Slow Start Test Results i

A test of the slow start capabilities of the Limerick diesels was conducted on June 20, 1988. The D13 diesel generator i

i 1 was successfully manually started to reach an idle speed of 300 - ;

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4 500 rpm per vendor recommendations. The engine speed was !

r q increased over a several minute period, to normal speed when the l j field was flached. The engine was then loaded in steps of l approximately 350 KW over a ten minute period to full load. The test proved the following:

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i a) Engine control system allows slow starts without '

) modification J

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b) There are no critical engine speeds during the acceleration phase.

Categories of Proposed Changes Changes to the Diesel Generator section of the Technical Specifications for the Limerick Generating Station, Facility Operating License NPF-39, are based on the Commission staff's "Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability", Generic Letter 84-15 and "Recent Engine Failures of Emergency Diesel Generators", I.E. Information Notice, 85-32, a

Norto Anna Pcuer Station license changes, and vendor recommendations.

The proposed changes in regard to the Limerick emergency l diesel generators fall into several categories or types of changes (1) Changes in the Technical specifications to specify pre- ,

lubrication and prewarming of diesel generators prior to !

starting fer testing purposes.

1 i Prelubrication/ prewarming would decrease the wear and

. stress on the diesel generator and would increase reliability and availability (Category A).

, (2) Changes in the Technical Specifications to provide for ;

t gradual acceleration and gradual electrical load 1 I increases to an indicated load value (band) during i i

diesel generator testing in order to decrease the

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I stresses inherent with rapid acceleration, sudden large.

l electrical load changes and routine overloading.in l accordance with vendor recommendations. (category B). I L

(3) Revisitsg the surveillance starting / testing frequency in

! i 1 order to . tim.t the incremental wear and stress on the M diesel generators (Category C). l.

8 j (4) Revising the accelerated starting test frequency program. f l so that it will be based on the number of failures in [

3

) the last 20 demands in lieu of the failures in the last '

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, 100 valid tests in order to maintain increased diesel ;

a r

] generator reliability without excessive and damaging I L

i surveillan.9e "cold fast starts" (Category D). i i I 1 4

(5) Changes in the Technical Specifications to allow diesel 1 (

generator maintenance inspections (la month terr down) while at power, rather than "during shutdown", in order l

]

to decrease outage time used for maintenance tear down l

j and allow more time for inspection in lieu of the l 4

requirement for tear down inspections only under a .i

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l limited outage schedule (category E).

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) (6) Incorporate the 184 day (paragraph 4.8.1.1.2.a.4) !

i starting surveillance into paragraph 4.8.1.1.2.h., !

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j allowing in this new paragraph for prelubrication and '

{ prewarming of the EDGs with electrica,1 loading to a band I value **hin 200 seconds.

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Also, the existing paragraph 4.8.1.1.2.a.4 and the single asterisk footrota at the ha* tem of page 3/4 8-3 would then be eliminatec from Spectrication 4.8.1.1.2.a tataggered test basis) (Category F)

Discussion - Category A Changes 8

The proposed Category A type changes to the Technical Specifications would allow prelubrication and prewarming of Emergency Diesel Generators (EDG) prior to preplanned EDG starts.

The NRC reported in Enclosure 1 to Generic Letter 84-15 that overall improvement in dietel engine reliability and availability l

can be gained by performing diesel generator starts using engine \

prelube to reduce engine stress and wear.

The proposed Category A changes listed below are similar in that these changes all relat? to prelubrication and prewarming prior to preplanned EDG starts.

l List of Category A Changes Page 3/4 8-3 Changes are proposed whic.:

would revise paragraph 4.8.1.1.2.a.4 eliminating the cold faut starts f'9m ambient conditions. The starting signals listed as a, b, e and d would be

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moved to paragraph 4.8.1.1.2.h to be verified every 184 days.

Page 3/4 8-3 The single asterisk i footnote would be revised to require prewarming and prelubrication of the EDGs prior to testing in paragraphs 4.8.1.1.2.a.4 and 4.8.1.1.2.a.5.

Page 3/4 8-5 A single asterisk footnote would be added to require prewarming and peelubrication of the EDGs prior to test.ing in ;

l paragraph 4.8.1.1.2.e.4.b, I

4.8.1.1.2.e.5 and r

I 4.8.1.1.2.e.6.b.

Page 3/4 8-6 A single asterisk footnote r

would be added to the page to require prewarming and prelubrication of the EDGs prior to testing in t f

paragraph 4.8.1.1.2.e.8. !

Page 3/4 8-7 Paragraph 4.0.1.1.3 Reporth would be moved to 1

s a new page 3/4 8-7a to enable insertion of a new paragraph "h".

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Page 3/4 8-7 A single asterisk footnote would be added to the page t

to require prewarming and f

prelubrication of the EDGs prior to testing in paragraph 4.8.1.1.2.f.

Page 3/4 8-7a A single asterisk footnote would be added to the page to require prewarming and prelubrication of the EDGs prior to testing in t

paragraph 4.8.1.1.2.h. i i

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Safety Significance-Category A Changes !

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Some surveillance testing under the existing Technical '

l Specifications requires EDG fast starts from ambient conditions. )

These tests subject the EDG to undue wear and stress on engine parts. The Commission staff in Generic Letter 84-15 concluded s

that the frequency of cold fast start tests from ambient f i

conditions, without a prelube or prewarm period, should be reduced. The Commission staff concluded that allowing for !

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j prelubrication and prewarming, based on industry experience and

] manufacturer's recommendations, increases the margin of safety by !

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s increasing the rcliability/ availability of the EDGs thereby decreasing the risk of station blackout.

Significant Hazards Consideration - Category A Changes

, The allowance for prelubrication and prewarming of diesel generators does not involve Significant Hazards Considerations. In order to support a No Significant Hazards Consideration determination, necessary background supporting information is provided below, along with an evaluation of each of the three standards set forth in Title 10 CPR Section 50.92.

Operation of the plant under the proposed Technical specifications in regard to allowing prelube and prewarming of the diesel generators prior to testing would not:

1) Involve a significant increase in the probability or consequences of an accident previously evaluated.

, Prelubrication and prewarming of the EDG engine prior to starting decreases the wear on the engine parts.

1 Industry experience demonstrates these measures to extend the life and thereby the availability of EDGs.

Testing EDGs f rom ambient conditions, without prelubrication/ prewarming of the engine, has been shown to cause incremental damage to the engine parts while the "cold started" engine is reaching temperature

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equilibrium.

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Industry experience has also shown that there are sufficient unplanned cold starts of the diesel generators because of various non-testing causes (s2ch as off-site power losses) *o demonstrate the "cold start" ability of the EDGs, without the need for also planning frequent periodic tests which are known to cause incremental damage to engine parts.

Therefore, the reduction in the number of "cold starts" of EDGs by specifying that all scheduled starts include prelubrication and prewarming, increases the availability of the onsite emergency power system and does not increase the probability or consequences of an accident previously evaluated.

(2) Create the possibility of a new or different kind of accident from any accident previously evaluated.

The operation and/or design of the onsite emergency power system is not being changed; only the surveillance methods and schedules. Therefore, based on the positive commission staff conclusions, along with industry experiences which have demonstrated the advantages of prelubrication and prewarming (EDG) starting procedures, the changes to the EDG testing methods do not create the possibility of a new or different kind of accident from any accident previously evaluated. The change in methods would continue to demonstrate the availability of EDGs as was previously evaluated, without the

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e incremental testing damage caused by test starts from ambient conditions. Unscheduled starts of the EDGs from emblent conditions are sufficiently frequent, to demonstrate their cold starting capability. The Safety Evaluation by the NRC Office of Nuclear Reactor Regulation related to Amendment No. 48 to License No.

NPF-7, North Anna Power Station, Virginia Electric and Power Company, reported the experiences of the NRC in reviewing reactor operating events, stating that a number of actual EDG demands occur that are not planned, due to actual loss-of power situations or to ESP actuations.

(3) Involve a significant reduction in a margin of safety.

The prelubrication and prewarming sequence has been demonstrated by industry experience to increase the reliability and therefore the availability of the EDGs.

Further, the Commission staff has concluded that all preplanned EDG starts should include a prewarming, prelubrication sequence. The proposed changes which would specify prewarming and prelubrication, therefore do not involve a significant reduction in a margin of safety.

Conclusion Based on the three standards discussed above, the operation of the facility after making the proposed Category A i

changes to the Technical Specifications, involves no Significant Hazards Considerations.

Discussion - Category B Changes The proposed Category B type changes to the Technical i

Specifications would allow gradual acceleration and gradual electrical loading of the generator during the surveillance i

tests, rather than rapidly accelerating and switching large '

electrical loads to the generator i n rapid incremental stages.

The proposed changes would also allow electrical loading to a band value rather than a specific load value to decrease the possibility of routinely overloading the diesel generators.

s The proposed Category B type changes listed below are similar in that the changes all relate to the manner by which the Emergency Diesel Generators are accelerated and electrically loaded during testing. Gradual acceleration and gradual electrical loading of the generator decreases the stresses on

both the generator and engine and therefore would be l

operationally advantageous, avoid premature wear, and lead to

, greater EDG availability. ,

Listing of Category B Type Changes i

Page 3/4 8-1 Changes are proposed Page 3/4 8-la to action statements Page 3/4 8-2 "a", "b", "c", "d", "f", j i

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i l "g" and "h" to include loading the EDG after every start per 1

vendor. recommendations by performing surveillance j

requirement 4.8.1.1.2.a.5.

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1 j Page 3/4 8-3 Changes are proposed which l would revise paragraph 4.8.1.1.2.a.4 to allow the

! EDG to be gradually 3 accelerated to synchronous speed rather than rapidly accelerated within less j than or equal to 10-

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seconds.

i Page 3/4 8-3 Changes are proposed which

) would revise paragraph j 4.8.1.1.2.a.5 to allow the i

l EDG to be gcadually loaded rather than loading the

] generator prior to I

4 establishing engine i

i temperature equilibrium.

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Page 3/4 8-3 A double asterisk footnote i

j would be added to page 3/4 j 8-3 which would add 4

j further explanation to the 1

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-t loading band'value i

indicated in paragraph 4.8.1.1.2.a.5. ;

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' Page 3/4 8-3 The proposed single asterisk, Page 3/4 8-5 footnote also includes direction ,

i Page 3/4 8-6 to perform surveillance test Page 3/4 8-7 in accordance with vendor r

y Page 3/4 8-7a recommendations regarding ;

I loading and shutdown.

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Page 3/4 8-6 Changes are proposed'which i I (

j would revise paragraph !

i 4.8.1.1.2.e.8 to allow [

j gradual acceleration of f

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the diesel generator and i I

gradual electrical loading i

j to a band value.

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j Page 3/4 8-6 A double asterisk footnote !

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would be added to page 3/4

} 8-6 which would add :

1 further explanation for j

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the loading band value j j indicated in paragraph {

J 1 1 4.8.1.1.2.3.0. l l

1 j Page 3/4 8-7a The signals for starting l

) the EDGs would be included i

r,- ,,---s,.n - , - - . , - , , , - - , , - . - , . _,,---,nn,-,w-r- n,-nn--n-,--,,s--,,-- -+- , -

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in a new proposad paragraph 4.8.1.1.2.h i along with a fast start every six months after

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prewarming and i t

prelubrication. l l

b Page 3/4 8-7a A double asterisk footnote would be added to page 3/4 i

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8-7a, which would add further explanation for i I

the loading band value l i

indicated in paragraph '

4.8.1.1.2.h. !

i Page 3/4 8-9 Proposed change to l

Surveillance Requirement 4.8.1.2 to delete i

exclusion of Surveillance Requirement 4.8.1.1.2.a... -

I Page B 3/4 8-1 Changes are proposed to indicate exception to Regulatory Guide 1.108, j "Periodic Testing of l Diesel Generator Units '

Used as Onsite Electrical l l

Power Systems at Nuclear !

Power Plants," Revision 1, !

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o o August 1977 to lillow gradual loading of diesel generators during testing.

Safety Significance - Category B Changes 1

The existing Technical Specifications require rapid !

acceleration of the diesel generators to synchronous speed in less than or equal to 10 seconds (4.8.1.1.1.2.a.4 and l 4.8.1.1.2.e.8) and rapid electrical loading to greater than or

equal to 2850 kW (4.8.1.1.2.a.5 and 4.8.1.1.2.e.8).

l The proposed ch.*nges to paragraphs 4.8.1.1.2.a.4 and

) 4.8.1.1.2.e.8 are to delete the requirement for acceleration to synchronous speed within 10 seconds to incorporate the vendor's i recommendations to gradually accelerate to synchronous speed over a1 to 2 minute period. Test procedures will be developed to I 1

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require the engine to start and automatically accelerate to an '

initial setting (idle speed) followed by manual increase of the speed setting to synchronous speed over a period of 1 to 2 i minutes. !

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The fast start of diesel generators has been identified I

as a contributing cause for diesel generator failures at the ;

} North Anna Power Station. Gradual acceleration during i 1

j surveillance tests was approved by the NRC staff for the North Anna Technical Specifications in April 1985. l 1

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e The proposed changes to allow gradual electrical loading l of the EDG upon synchronization incorporates vendor recommendations into the surveillance testing requirements.

Industry experience and Commission staff conclusions reported in Enclosure 1 of Generic Letter 84-15 support gradual electrical

] loading of the generators as a factor which leads to more ;

j reliability and availability of the CDGs. Increased rollability ,

J and availability of the EDGs decrease the possibility of a station blackout. ,

i The proposed single asterisk on Pages 3/4 8-3, 3/4 8-5, l

4 3/4 8-6, 3/4 8-7, and 3/4 8-7a includes direction to perterm surveillance tests in accordance with vendor recor.tmendations t

! regarding loading and ahatdown in addition to previously ,

l discussed prelubrication and prewarming. This proposed change !

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will assure the EDGs are operated in accordance with vendor

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recommendaticns during all planned tests in order to extend ;

t diesel life and improve reliability. '

The changes to action statements "a", "b", "c", "d",

1 "f", "g" and "h" to require the performance of both Survel' j Requirements 4.8.1.1.2,a.4 and 4.8.1.1.2.a.5 rather r,han just [

J i 4.8.1.1.2.a.4 alone, are proposed to incorporate vendor [

i 1 i recommendations regarding diesel operaticn. The vendor ,

] recommends that every planned EDG start be followed by a 60 2

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, minute loaded run at at leact 60% continuous rating. The change !

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to page 3/4 R-9 to delete the exclusion of surveillance l

tequirement 4.8.1.3.2.a.5, requires the EDG to be loaded to ;

' I demonstrate its operability. These changes would provide j 4

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assurance that every surveillance teat-related EDG start is followed by a loaded run which will increase the reliability and a.uallability of the EDGn.

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The prcposed changes also allow that UDGs to be loaded to a band of 2000-2700 kW rather than greater thau or equal to 2850 itW to prevent routine overloading during the performance of the monthly surveillance tests. The load value of 3135 kW for the 2-hour portion of the 24-h0ur test of paragrapn 4.8.1.1.2.e.8 would i be changed to a band of 2800-2900 kW to provent overloading the diesel generator to greater than 110% of its continuous rating.

j The general requirements for periodic diesel generator surveillance testing are established by Regulatory Guide 1.108 i and the Standard Technical Specifications. These specify that

during the monthly test, tbc EDG is to be loaded to the i continuous duty rating. "urther, during the 24-hour load run i

i conducted on a 18-monto basis, the EDG is to be loaded to the 2-hour rating for the first 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , followed by 22 hours2.546296e-4 days 0.00611 hours 3.637566e-5 weeks 8.371e-6 months at the continuous duty rating. The monthly test chould exercise the LDG, confirm its operability, and detect degradation or a failure before a second EDG failure is likely to occur. During the 18-month testing, the proposed test load envelopes the calculated

maximum acciden'. loads. It is our position that it is not necessary or desirable to ervelope the design basis accident s

loads by a toat wnich is repeated 12 times a year. The potential to rcutinely overload the EDG is tco great and the 18-month test ,

adequately verifies the EDG's capability to supply the design t

basta accidens loads. Gradually loading the EDG to 2600-2700 kW h

=2)- I 1

during the monthly testing allows verification of the operability of the EN) at greater than 90% of its continuous duty rating of 2850 kW.

Loading the EDG to 2800-2900 kW during the 2-hour <

portion of the 24-hour test conducted every 18 months, confirms

] the EDG's capability to supply the maximum calculated design !

j basis accident loads while providing enough margin to the 110% i continuous duty rating value of 3135 kW to prevent overloading.

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The maximum design basis accident load of 2805 kW is presented in .

4 PSAR Table 8.3-2, t

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S i g n_i_f i ca n t Hazards considerations - Category B Changes

) Gradual acceleration and gradual electrical loading of the Emergency Diesel Generators decrease the stresses on the diesel engine and generator. Loading the EDGs to a band value i l

would prevent potential routine overloading on a monthly basis l, and during the 18-month testing. The proposed changes to the !

j Technical Specifications do not involve Significant Hazards '

)

3 Consideratione. In order to support a No Significant Hazards Consideration determination, the supporting information in regard ,

to Category B changes is provided below, along with an evaluation

) of each of the three standards set forth in Title 10 CPR Section 1

50.92.

i !

l Operation of the facility under the proposed Technical 3 Specifications allowing gradual acceleration and gradual

electrical loading of the generator during testing would nots

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(1) Involve a significant_ increase in the possibility or c9nse,quences of_an accident previously ey31uated.

Licensee proposes to change the surveillance test requirement (4.8.1.1.2.a.4 and 4.8.1.1.2.e.8)

"accelete.te to synchroncos speed (882 rpm) in less than or equal to 10 seconds" to "gradually accelerate to synchronous speed" in order to incorporate the vendor's recommendation to gradually accelerate to synchronous speed over a 1 to 2 minute period. Existing Technical Specifications require monthly testing of each diesel generator, demonstrating that the diesel starts from ambient condi.tions end verifying synchronization and loading to greater than or equal to ?850 KW, then operating with this electrical load for at least 60 minutes. Licensee proposes to change the loading requirements to allow the diesel engine to first reach temperature equilibrium before gradually loading the generator to 2600-2700 MW, tnen' operating for 60 minutes. Licensee also proposes to test the CDG to a load of 2800-2900 kW rather than 3135 kW during the 18 month test to reduce the poselbility of overloading the diesel and continue to envelope the design basis accident loads presented in FSAR Table 3.3-2. By establishing temperature equil.ibrium prior to loading the generator, then gradually loading up to a band of 2600-2700 kW for the monthly tests and 2800-2900kW for the 18 month tests, the routine overloading and over-

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! stressing of the diesel engine would he avoided. Stress i from cold fast starts and from sudden large electrical t

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{ ulcad swings on the generators has been ' reported by

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nuc: lear industry groups _ (INPO .and American Nuclear' -

l Insurers) to affect the reliability and the availability a i

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.. cf diesel generators because of incremental'and , , o j s

premature engine wear. Gradual increases in electrical '

^

loading, along.with prelubrication ated prewartning' were ,

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.. l reported to be a factor which would. increase the r l

1 availability of the EDGs. !

.In order to extend the life of the EDGs, testing the r

ability of the EDCs to synchronize and supply the design 1

[

1 basis accident .\oads would be tested every 18 months in <

j lieu of the ecisting 31 day cycle. The proposed testing - ,

{ requirements would still verify the ability of'the EDGs '

I to start, synchronize, and accept lthe rated loads i l j

required for safe shutdown. The proposed changen to j 3

allow gradual acceleration of the EDG to synchronous t i

speed, gradual electrical loading to a. band of 2600-2700 '

t l

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kW for the monthly tests and 2800-2900 for the 18 month j I

tests, do not involve a significant increase in the '

I j possibility or consequences of an accident previoucly 1

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evaluated. '

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l, (2) Creace t,he possibility of a new and differe,nt kind of _

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accident,from any accident previously eva.tuated. . '

l 4

J J q a

j 1 .

l 1

. - ,,,_%,,,_w,__,,.,..,,.._.__,._,,_.-~.,.,__..,_,.-,.,,,4.....,--,,i,,...,,,-i...,m. . . . ~ , , , . ~ . . . , , . m.

a

Changing the rete of acceleration and electrical loading

? of the diesel generators under test to allow gradual asceleration and gradual loading, rather than starting the EDGs, tapidly accelerating, synchronizing and e rapidly loading to the rated continuous capacity of 2850

.< w , does net change the operation or cesign of the EDGs, but merely decreases the harsh and stressful EDG testing requirements. The (startiag) avail.)bility of the EDGs 1 is still tested on a frequent (31 day) basis, while the capsbility to supply the design basis accident loads is t testod on a less frequent, 18 month cycle.

Therefore, testing the availability (starting) of the EDG s on a f requent basis, while testing the capability i (londing) of the EDGs on an 18 month cycle, does not l create the possibility of a new or differont kind of r

accident from'any accident previously evaluated, I ,

(3) Involve a signMicant redigetion in a ma rgin of aafety, i

, The proposed changes to the acceleration and electrical loadiag of the diesel generators doec not change,tne i

availability or capabi.11ty of the EDGn. The availability of the EDG will be cented on a Crequent :

l a

monthly basis and the capability of the EDJ to supply the design basis accident loads will be tosted on .in 18 '

1 e

month basis. The reduction of the load value for 'he t 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months portion of the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months test f rom 313') kW.to 2600- k 2900 kW does not reduce the effectiveness of the test i 1

4 1

t

I-

. n

?

because the maximum design basis accident load of 2805 kW is enveloped by the band of 2800-2900 kW. I i

Decreasing the harsh and damaging manner of testing

. i would lead to greater availability of the EDGs and !

therefore the proposed Category B type changes do not I involve a significant reduction in a margin of safety.

i Conclusion

-l ,

r I

Based on the discussion above in regard to the three !

1 j standards of Title 10 CFR Section 50.92, the proposed change in the sequence of electrical loading during EDG testing, involves f

no Significant Hazards Considerations. '

Djscussion - Category C changes I

The Category C type changes would revise the 4

I surveillance starting and testing frequency requirements for EDGs '

i in order to limit the stress and wear on the EDGs. ,

I i

l The proposed type C changes listed below are all inter- i I

\

related in that these Category C type changes all relate to the j 4

! frequency at which the EDGs are tested for various reasons, i t

I List of Category C Type Changes t t

)

J l

t Page 3/4 8-1 The proposed change to l

action stateoent "a" would I i

s I

delete the requirement to immediately test the remaining EDGs if the 1

reason for the one EDG being inoperable is preplanned preventative maintenance, modification, or testing.

Page 3/4 8-1 Proposed addition of an asterisk '*' to action t

statement "a" to require

testing of the remaining EDGs if the reason for the EDG being inoperable is 1 potentially generic for >

the remaining EDGs, j regardless of when the inoperable EDG is restored

] to OPERABILITY.

J i

j Page 3/4 8-1 Proposed changes to action statement "b" would allow commencement of the initial EDG tests within 8 3 hours, rather than I

r l completion within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months

l 4

and delete the requirement i

j I

j for repeat EDG testing 1

a every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

d Page 3/4 8-la Proposed changes to action 1

[ statement "c" would allow ;

l commencement of the initial EDG tests within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and delete the !

i requirement foti repeat EDG ;

i I

, testing every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

! l Page 3/4 8-la Proposed changes to action i I

j statement "d" delete the !

l . !

j requirement for testing (

j the remaining EDGs if the l 1

I reason for being i

(

inoperable is known and j

! preplanned. l t ,

I '

I !

j Page 3/4 8-la Proposed change to action l' t

j statement "d" to increase !

I the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months action time for ;

l initial testing of EDGG to I

]- ;

] 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months and to delete the 1 f 4

requirement for repeat EDG f c

testing every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

i ,

t' I

Page 3/4 8-la Proposed addition of an i t

j asterisk '** to require I J testing of the remaining

L J

l !

1 :

EDGs if the reason for the EDG being inoperable is potentially generic for 1

j the remaining EDGs, l

regardless of when the inoperable EDG is restored to OPERABILITY. .

Page 3/4 8-2 Proposed changes to action t statement "f" would delete l 1

I

] the requirement for repeat i

} EDG testing every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

t Page 3/4 8-2 Proposed change to action statement "f" to increase i i

! the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months action time for [

! t j initial testing of EDGs to

{ 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . !

l

. t I

Page 3/4 8-2 Proposed change to action !

I

{ statement "f" would allow l

{ credit for EDG tests i

completed within the !

preceding 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , l

Page 3/4 8-2 Proposed change to action l

statement "g" would allow i

! commencement of the !

t i

initial EDG tests within 8 i s, !

4 hours, rather than I i

4 l

completion within I hour and delete the requirement for repeat EDG testing every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

Page 3/4 8-2 Proposed changes to action statement "h" would allow commencement of the initial EDG tests within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , rather than completion within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and delete the requirement for repeat EDG testing every 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

Safety Significance - Category C Changes The NRC staff concluded in Generic Letter, 84-15 that the f requency of starting tests of EDGs f rom ambient conditions should be reduced. The conclusion was based on industry experience with premature failure of EDGs due to stress and wear caused by excessive starts.

Licensee proposes changes to ac* ion statement paragraphs

'a' and 'd' to delete the requirement to immediately test the remaining CDCs if the reason for the one E9G being inoperable is ,

preplanned preventative maintenance, modification, or testing. !

EDGs are surveillance tested in order to demonstrate operability.

Whenever one (or more) of the EDGs becomes inoperable, the action l

statement requires that the availability of the other EDGs is to be demonstrated, in order to assure that any unknown (or undiscovered) generic problem does not exist on the other EDGs. r In those cases where the reason or cause of the one EDG belug inoperable is known to be due to preventive maintenance, J

modification work or during testing, then surveillance testing of i the remaining EDGs is not justified and adds incremental i unnecessary engine wear due to starting stresses. Therefore, in t

! those cases where the cause or reason for one of the EDGs J

becoming inoperable is known and preplanned, and not the result of a generic problem, Licensee proposes to delete the requirement j of testing all of the remaining EDGs within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

l

! Licensee also proposes an addition of an asterisk to a

l, paragraphs 'a' and 'd' to require teJ,cing of the remaining EDGs )

i l, when the reason for the one EDG being inoperable may be l 1

j potentially generic to the remaining Unit 1 EDGs and appropriate alternative testing cannot be designed, regardless of when the

)j EDu is rectored to operability. Even if the inoperable EDG is ;

i restored to service prior to expiration of the required test period, it remains important to demonstrate the availability of ,

the remaining EDGs to assure that any generic problem does not l' l

exist in the other EDGs. Although this restriction may increase i the number of EDG starts, the verification of EDG availability 3

would increase EDG reliability by decreasing the possibility for l.

! a generic problem to affect the other EDGs' operability, ,

4 l a t l !

i

t l

l

)

i I

I Licensee proposes to change action statement paragraph j 'f' to allow credit for successful EDG tests completed within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of the required action start time. This change is proposed I

in order to reduce the number of unnecessary diesel starts and

] therefore increase the reliability and lifespan of the EDGs. ,

Reasonable assurance of starting capability having been

demonstrated during the previous 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months would remain within the I same timeframe as that required in the existing action statement, i maintaining the safety margin in regard to possible station blackout. The EDGs which had been successfully tested during the f I

previous 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months would then need only be tested again at least ,

J 1 once every 7 days.

I l

{ Changes are also proposed to paragraphs 'b', 'c', 'd',

'f', 'g' and 'h' to delete the requirement for repeat . sting of i l

)

] the EDGs af ter the 1."itial tc ts are performed. In the North f 5

i e\nna SER dated April 25, 1985, the NRC referenced a test interval !

l '

j of 3 days to be optimal for verification of EDG operability when I i

i

a plant system is already degraded. For these paragraphs, a j l-repeat EDG test interval of 3 days after the initial tests would !

not occur within the Action recovery time limit of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , i

Deleting the requirement for repeat EDG tests, where applicable, t j

a j eliminates unnecessary and excessivi testing of the EDGs.

i ;

To allow a more orderly denonstration of operability 1

i ncluding prelubrication and prewarming of the EDG engine, along l, with gradual electrical loading of the gencrator, the Licensee i f proposes to change paragraphs "b", "c" and "g" to commence the demonstration of operability within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months rather than complete f i i i

i i.

_ _ _ _ _ _ __._.____________m__.-_____m _ _ - _ _ _

l

] the test within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months . Changes are proposed to increase the one

] hour action time for the initial test of the remaining EDCs in l action statements "d" and "f" to 8 and 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , respectively, to i allow more time for the plant operators to respond to immediate accident conditions and plant abnormalities. The 8 and 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 1

periods reflect the degree of degradation of the A.C. electrical power sapply. Eight hours would be allowed to begin testing EDGs j in the event of one offsite circuit and one EDG are inoperable, j Twenty-four hours would be provided to begin testing of EDGs when j one offsite ircuit is inoperable. The proposed more orderly

] demonstration of operability would decrease the stress on the

! EDG, result in greater EDG availability, and provide plant l operators more time to respond to abnormal plant conditions.

J l

l The Licensee does not propose any changes to the senedule or methods for offsite-to-onsite circuit verification or j any changes to the periods allowed for recovery from degraded conditions.

Significant Hazards Considerations - Category C Changes The Category C type changes to the Technical Specifications pages 3/4 8-1, 3/4 8-la and 3/4 8-2 paragraphs "a", "b", "c", "d", "f", "g" and "h" involve No Significant Hazards Considerations.

In support of this No Significant Hazards Ccnsideration conclusion, the proposed Category C type changes are reviewed below using the three standards of Title 10 CPR Section 50.02:

(1) Operation of the plant in accordance with the proposed i

amendment does not , involve a significant increase in the probability or consequences of_an accident previously 1

evaluated.

Revising the starting and testing f requincy of the EDGs to take credit for previous successful tests, deleting

] unnecessary EDG starts when one of the EDGs becomes inoperable because of preventive maintenance, !

I modification or during testing, and deleting unnecessary l repeated testing of the EDGs after initial verification 1

i of availability will reduce the incremental wear and '

i i stresses resulting f rom excessive EDG starts. Further, i

l l the proposed changes would allow testing, when required, ;

l to commence eithin one hour, in lieu of the requirement i

for being complete within one hour. The changes also {

l increase two action time limits to allow plant operators l.

j more time to respond to abnormal plant conditions. The :

increase in these times does not significantly affect !

! EDG reliability or availability. The level of assurance ;

l that the EDGs will be available when needed will not be e 1

decreased by these changes and the proposed decrease in ;

the number of test starts will increase the reliability and availability by reducing engine stress and Near.

Therefore, the proposed Category C type changes do not involve a significant increase in the probability or !

1 consequences of an accident previously evaluated. ,

l i

34- :

i l

I i

(2) Operation of the plant in accordance with the proposed amendment docs not create the possibility of a new or different kind of accident from any accident previously, l i

evaluated. l The operation and/or design of the onsite emergency

power system is not being changed, only the frequency of the surveillance testing starts and the reasons for the tests. Assurances of EDG availability would be maintained by surveillance at a different frequency, r

i with the proposed changes eliminating unnacessary EDG starts, which would increase EDG availability.

Therefore, the proposed type C changes, including taking credit for successful tests within the previous 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months along with eliminating unnecessary test starts on EDGs ,

j whenevet one EDG is inoperable because of preventive 4

i maintenance, modifications or during testing, does not !

l, create the possibility of a new or dif ferent kind of I accident from any accident previously evaluated. '

j (3) Operation of the plant in accordance with the proposed 2

j i amendments would not Anvolve a significant reduction in i i

I a margin of cafety.

The proposed Category C type changea to revise the EDO l

surveillance testing frequency would continue to assare e

1 the availability of the EDGs. The verification schedule

, and method for assuring offsite-to-onsite power circuits I would remain without change, while unnecessary EDG test

i e

'f 1

starts would be decreased. Eliminating the present I

requirement for starting all the remaining EDGs whenever any one of the EDGs has been declared inoperab'e for- ,

I preventive maintenance, modifications or testing and' !

taking credit for tests successfully completed within l previous 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months will increase the availability of the

]

. EDG. Eliminating EDG testing shown to be unnecessary 1 ;

without significantly decreasing the assurances od availability, does not involve a reduction in a margin I of safety. Reduction in "testing starts" has been shown t i i by industry experience to increase the reliability of i

)

the EDGs.

I j conclusion i

j Taking credit for previous successful tests and !

i

eliminating unnecessary testing of the EDGs, has been shown by I industry experience to dectease the wear and stress on EDGs. i 1

BdSed on the earlier discussion above, the propcSed Changes to ,

pages 3/4 8-1, 3/4 8-la, and 3/4 8-2 paragript.s "a", "b", "c",

"d", "f", "g" and "h" involve No Sig.;ificant llazards Ocosiderations, l i i

Discussion - Category D Changes i

t Tne category a 'ype enanges to the Technical Specifications would revise the accelerated testing frequency

] program in order to maintain increased diesel generator (

r i

36-i

reliability without unnecessary excessive and damaging I

surveillance tests. l l

All of the Category D type changes listed below can be grouped together because they involve the Emergency Diesel Generator accelerated testing program.

List of-catagory D Type Changes Page 3/4 8-8 Proposed changes would be

made to table 4.8.1.1.2-1

changing the test schedule.

1 l

Page 3/4 8-8 Proposed changes would be l

made to the single asterisk footnote to l change the determination of failures from a "Unit basis" to a "per diesel '

generator baais" and k delete reference to Operating License issuance date.

Page 3/4 8-8 A proposed double asterisk footnote would be added to page 3/4 s-8 which would

allow testing the EDGs on a 31 day cycle after seven i

t

ccnsecutive failure free l demands are accomplished.

T- / ,

Page 3/4 8-8 Proposed change to allow credit for a complete i

diesel engine overhaul.to r

reduce the record of engine failures to zero (0).

Page B 3/4 8-1 Changes are proposed to indicate exception to l Regulatory Guide 1.108, Revision 1, August 1977 to 4

- allow decreased frequencies for diesel

! generator surveillance I 4

testing. ,

I Saf,ety Significance - Category D Type Changes The existing Technical Specifications require !

acceleration of the EDG surveillance frequency as the failure i rate increases from "1 failure" to "greater than 4 failures" per 100 tests. When the failure rate increases beyond 4 failures, l 1

] then the surveillance testing frequency increases from "at least ; !

] .

once per 31 days" to "'at least once per 3 days". At the 3 day j accelerated testing frequency, the incremental damage caused by o l I i 1

r e

w-. --.w-w--.m y

wr-w.~w- , ,m ,w%~--m-+,- ye- ,. 7m n g ,,wm----,-- fm<< - ,y;1++--y-e, --w-r ev--r*------- ,..ve,-

.. a P

the stress and wear on the engine from starting and stopping so

, frequently, causes rapid accelerated damage.

The Commission staff concluded in Generic Letter 84-15 y that a more ef ficient method of testing the EDGs was needed to assure continued availability. Elimination of the unnecessary 3

. day and 14 day accelerated testing frequency was therefore

( recommended as a means of decreasing the number of damaging EDG '

I starts i.e., the accelerated testing frequency also accelerates ;

, the wear on the EDG, thus rapidly escalating damage until complete fail'ure of the EDG occurs. ;

The guidance in the NRC Staf f, Generic T,etter, 84-15 included provisions for maintaining diesel generator reliability l at or above specified levels, with 0.95 being stipulated as the !

minimum desired and acceptable reliability leve' In order to 3

assure that this level is maintained, an accele...ed test prograA I was still recommended, however the accelerated program would be ,

, based on the number of failures in the last 20 demands on a per t diesel generator basis, in lieu of t'.e existing program which is i j

t based on the number of failures in the last 100 tests. The 3 day l l

, and 14 day testing cycle would also be eliminated by the i i recommendations in Generic Letter 84-15. I I l l

?

a The Category D type changes include an accelerated test program which would maintain the minimum desired level of reliability at or above 0.95, while changing the program basis from "failures per 100 valid tests" to "failures in the last 20 valid demands". This change in the program basis would be f j l 1

l 5

l l l

I

i A %

, advantage,ous, would follow the recommendations of Generic Letter 84-15 and would allow for fewer unnecessary testing demands on the EDGs, while maintaining assurances of availability which would continue to be provided by the existing specifications.

The 0.95/ demand, minimum reliability goal would be demonstrated by accelerating the EDG testing to at least once per l 7 days whenever there is more than one failure per 20 demands (

! (per EDG) 1.e., 1/20 = 51 failure, 95% reliability. l f

, once the surveillance testing is accelerated because of l a demand failure, a means is needed for returning the I surveillance tes'.ing to normal following demonstration of acceptable operation. Based on Generic Letter 84-15, the

- i Licensee proposes to add the double asterisk footnote allowing (

return to the 31 day surveillance testing once seven consecutive failure free demands have been performed and t u number of I j failures in the last 20 valid demands have been ieduced to one.

The footnote would then allow the minimum reliability goal o' O.95 to be maintained.

I i

j Changing the testing frequency and changing the test l pattern basis from "failures per 100 valid tests" to "failures l J

] per 20 valid demands" therefore does not significantly affect the , )

! margin of safety.

i 4

j Licensee proposes an additional change to Table 4.8.1.1.2-1, "Diesel Generator Test Schedule", on page 3/4 8-8.

l The change would allow credit for a complete diesel engine overhaul to reduce the record of engine failures in the past 20 I

{ i 4

~ - - - - - - . - - . - . - ~ ---.-.-.-----,-,.-...---,.-.n. - -

or 100 tests to 0. The change provides an incentive for the Licensee to perform a comprehensive overhaul to rebuild an engine j to like-new conditions when an EDG is experiencing repeated failures. The overhaul would have to be approved by the EDG manufacturer and the EDG would become operable only after it j successfully passes the appropriate tests. The EDG reliability

~

i would be demonstrated by successful completion of 14 consecutive j tests: 10 tests would include gradual acceleration and loading to the nonthly limit (2600-2700 kW) and 4 tests would include the six month test requirements of rapid acceleration and loading.

4 This change will increase the reliability of the EDGs by 1

] providing an incentive to overhaul an EDG when it experiences j repeated failures.

Significant Hazards Considerations - Category D Changes Revising the accelerated testing frequency for EDGs based on the number of failures in the "last 20 valid demands" in lieu of the failures in the "last 100 valid tests" along with eliminating the unnecessary 3 day and 14 day accelerated testing

! cycle does not involve Significant Hazards Considerations.

In order to support this No Significant Hazards l Consideration determination, necessary background supporting information is provided below, along with an evaluation of each j

of the three standards set forth in Title 10 CFR Section 50.92.

I i

i i

j I 1

l t . . . _ _ _ _ _ _ - -

n d

,, 1 l o Operation of the plant under the proposed Technical l

Specifications in regard to revising the accelerated testing '

program would.not: ,

-(l) Involve a significant increase in the probability or t consequences of an accident previously evaluated.

The minimum reliability level of 0.95 for the EDGs is

)

) maintained by the proposed Category D type changes in the accelerated testing program, even though the- !

unnecessary and damaging 14.and 3 day testing cycles would be eliminated. Operating the facility under the i proposed Technical Specifications would' increase the availability and lifespan of the EDGs an(. therefore would not increase the probability or consequences of an '

i accident previously evaluated.

i ,

l (2) Create the possibility of a new or different kind of 1

accident from any accident previously evaluated.

1 The surveillance methods for demonstration of EDG '

operability would not be changed, nor would the minimum i

reliability level of 0.95 for EDGs. The surveillance i schedule and frequency would be changed however, in [

l

order to decrease the harsh and damaging testing ,

1 -

frequency of starting and stopping the EDGs. The ,

{ changes to the accelerated testirig frequency would !

l increase the reliability of the EDGs and therefore the I

v proposed Category D type changes do not create the t l 1

) !

l 1 l 4

p

.. s possibility of a new or different kind of accident from any accident previously evaluated.

4 (3) Inysive a significant reduction in a margin of safety.

The assurances of availability for the onsite emergency r

power system atr derived from the verifications of the r offsite-to-onsite circuits and the surveillances of the 4

I EDGs to demonstrate availability. The margin of safety '

j includes the demonstration of a minimum 0.95 reliability a

for the EDGs by use of an accelerated testing program.

The proposed Category D changes do not revise the frequency or methods of surveillance for the offsite-to-onsite power circuits, only the frequency at which the EDGs are tested after one or more of the EDGs has failed. The decrease in EDG testing frequency will not !

significantly arfect the margin of safety and because of .

4 industry experience, it has been found that the decrease in testing frequency is a factor in increasing EDG availability. j i .

4 Conclusion !

s f

i i

Based on the discussions above, the Category D type l i

) Changes do not involve Significant Hazards Considerations. !

4 i i

r 4 !

l

, f 5

t 1

t t

[

Discussion - Category E. Changes '

The proposed Category E type changea to the Technical Specifications would allow the 18 month maintenance (teardown) inspection and other surveillance tests to be accomplished while

at power rather than only when shutdown.

i' i

The Category E' changes all relate to allowing the i

maintenance tear down inspection while at power. ;

Safety Significance - Category E Changes t

Existing Technical Specifications on page 3/4 8-4 .

paragraph 4.8.1.1.2.e stipulate that the diesel generator must f have an inspection in accordance with the manufacturer's i i recommendations every 18 months "... during shutdown ...." '

i Preplanning the teardown inspection so that the EDGs can be {

inspected (one at a time) on a staggered basis over the 18 month period would avoid the time constrained type maintenance !

l inspection presently allowed only during outages while the unit is shutdown. The less time constrained tear down/ inspection I l would allow opportunity for a more detailed tear down and

! inspection.

I i

The existing Technical Specifications when vin d in '

i t j respect to Generic Letter 84-15 appear to reflect a typical BWR i i

l i

with only two EDGs for each unit. Limerick has four dedicated l i

EDGs for each unit (eight for two units). Chapter 8 of the Final l

i l

i Safety Analysis Report evaluated the loading requirements for ,

J i

each EDG during a design basis accident. The evaluation j t

i )

I

i conclude.J that having one EDG out of service will not significantly impact the operation of the onsite emergency system. Three of the four EDGs are capable of emergency shutdown

.of the plant. following a design basis accident. !

l In addition, the requirement "during shutdown" is not .

t necessary because the operational condition is governed by the operability of equipment already prescribed as necessary in !

4 Technical Specification 3.8.1.1. It'is inappropriate to ;

i delineate the specific operational condition the plant must be

{

placed into within the body of the Technical Specification !

surveillance test requirements. If a specific surveillance test 3

requires that the plant enter a Limiting Condition for Operation I (LCO), then the plant response is'already defined in the Action Statements associated with that LCO.

f An analagous change has been p;<viously approved by the 1 NRC staff in the Safety Evaluation Report for Susquehanna Unit 1 L f

dated April 12, 1985.

, Based on tne existing Limiting Condition for Operation, the presence of four EDGs per unit in lieu of the typical BWR

?

arrangement of two EDGs for each unit and the operational :

1 condition being governed by Technical Specification 3.8.1.1, the I 1

proposed change would not significantly affect the ability of the l

(

1 1

onsite emergency power system to shutdown the plant safely, j

! t

! I i

I -

4 4

h

-4s- .

t i !

l i'

1 Significant Hazards Consideration --Category E Changes I Allowing the EDGs to be' inspected one at a time while L

the unit is at power, rather than only while shutdown involves No i Significant Hazards Considerations.

I l In order to support this No'Significart Hazards Consideration determination, necessary background supporting ,

information is provided below, along with an evaluation of each i of the three standards set forth in Title 10 CFR Section 50.92.

Operation of the facility under the proposed Technical I

Specifications in regati to allowing the EDGs (one at time) to be inspected (tear down) while the unit is at power would nots l

j (1) Involve a significant increase in the possibility or r

consequences of an accident previously evaluated.

The operational condition is governed by operability of the equipment prescribed as necessary in Technical .

l -

Specification 3.8.1.1 and the action statements define j the plant response. l I

l The proposed Category E changes would require that the t

requisite number of diesel generators be in an operable I

condition, but would eliminate the restriction that the i ,

18 month maintenance inspection and other surveillance l l tests be performed only while the unit is shutdown. l l Because all operational conditions and the associated

! actions are defined elsewhere in the Technical !

I !

j l i

, t t i

Specifications, the removal of this restricticn would not involve a significant increase in the probability or consequences of an accident previously evaluate 6.

(2) Create the possibility of a new and different k}nd of accident from any accident previously evaluated.

The proposed Category E changes will not change the method in which any of the 4.8.1.1.2.e surveillance activities are to be performed, only the prescriptive operational condition in being removed. Since the operational conditions and associated actions are defined elsewhere in the Technical Specifications, the removal of this restriction will not create the possibility of a new and different kind of accident from any accident previously evaluated.

(3) Involve a significant reduction in a margin of safety.

The margin of safety for the emergency power system depends on the proven, historical reliability of the EDGs and the surveillances verifying the power circuits between the offsite and the onsite power systems. The elimination of the restrictions for performance of tt.e maintenance tear down inspection would remain within the existing action parameters of Technical Specification 3.8.1.1. Therefore the proposed change does not involve a significant reduction in a margin of safety.

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.* *- t .

.)

conclusion-Based on the discussion above in regard to removal of ,

the restriction for completing the 18 month EDG maintenance ,

I inspection while at power involves No Significant Hazards i

. . 1 i

Considerations.

f ,

f Discussion - Category P Changes !

' l j The proposed Category F changes to the Technical

{

Specifications would modify paragraph 4.8.1.1.2.a.4 along with l the footnotes at the bottom of page 3/4 8-3 having a single asterisk and incorporates the 184 day EDG starting surveil. lance under a new paragraph 4

"h" in specification 4.8.1.1.2.

All of the Category F type changes are gro' aped together j

{ since they involve maintenance of a provision for prewarmed.and prelubed fast start testing of the EDGs.

l i

i Safety Significance - Category F Changes ;

l The existing 184 day surveillance would require the EDGs i to be started from ambient conditions, without prelubrication or j prewarming. Based - e Commission staff Generic Letter 84-15, and on further industry experience deceribed in I.E. Information jl Notice 85-32, Licensee proposes to reduce the unnecessary and !

damaging starts from ambient conditions by providing for fewer starts and by alps.*ng for prewarming and prelubrication. !

Reduced stress and wear on the engine by prewarming and

prelubrication, has been found to be a fcetor which would contribute to a longer lifespan on the EDGs and would therefore decrease th* tisk of a station blackout.

Significant Hazarda Considerations _- Category F Changes Modification of paragraph 4.8.1.1.2.a.4 while adding paragraph 4.8.1.1.2.h to the Technical Specifications would decrease the number of damaging cold fast starts. The Category P changes would not involve Significant Hazards Considerations.

In order to support a No Significant Hazards Consideration determination, necessary background supporting information is provided below, along with aa evaluation of each of the three utandards set forth in Title 10CFR Section 50.92.

vperation of the plant under the proposed Technical Specifications in regard to the 184 day surveillance requirements would not:

(1) Involve a significant increase in the probability or consequences of an _ accident previously evaluated.

Industry experience has shown that there are sufficient unplanned cold starts of the diesel generators because of varisus non-testing causes such as off-site power losses. to demonstrate the "cold fast start" ability of the EDG , without the need for also planning prciodic tests which are known to cause incremental damage to j

engine parts. Providing for the availability demonstration by surveillance "fast starts" at least every 184 days, while allowing prewarming and ;

j. prelubrication would not involve a significant increase in the probability or consequences of an accident previously evaluated.

l 4

(2) Create the possibility of a new or different kind of '

accident from any accident previously evaluated.

! The operation and design of the onsite emerg)ncy power

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j system is not being changed; only the surveillance f methods and schedules in regard to the EDGs. The change o

in surveillance methods and schedules for the EDGs would l continue to demonstrate the availability of the EDGs as previously evaluated, without the incremental r.esting damage caused by test starts from ambient conditions. l Unscheduled starts of the EDGs from ambient conditions i l

3 are sufficiently frequent to demonstcate their cold 1 l 1 starting capability which eliminates the need for a

scheduled cold damaging starts. Therefore, the proposed t

i changes would not create the possibility of a new or !

i j different type of' accident.

l; (3) Involve a significant reduct; ion in a raargin of safety !

The prelubrication and prewarming aequence has been !

1 7 demonstrated by industry experience to increase the 1 l

reliability and therefore the availability of the EDGs.

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Further, the Commission staff has concluded that all preplanned EDG starts should include a prewarming, prelubrication sequence. The proposed changes which would specify prewarming and prolubrication, therefore do not involve a significant reduction in a margin of safety.

Conclusion Based on the discussion above operation of the facility under the proposed Technical Specifications in regard to allowing prewarming and prelubrication prior to the 184 day surveillance does not involve a Significant Hazards Consideration.

Environmental Considerations 1

An environmental impact assessment is not required for i the changes requested by this Application because the requested changes conform to the criteria for "action eligible for I

categorical exclusion" as specified in 10 CFR 51. 22(c)(9). The ,

I requested changes will have no impact on the environment. The j Application involves no significant change in the types or significant increase in the amounts of any effluents that may be l l

released offsite, and there is no significant increase in individual or cumulative occupational radiation exposure. The Application involves no rignificant hacards consideration as demonstrated in the preceding section.

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f

, Conclusion i

The Plant Operations Review Com:nittee and the Nuclear Review Board have reviewed these proposed changes to the Technical Specifications and have concluded that they do not involve Significant flazards Considerations and will not endanger the health and safety of the public.

Respectfully submitted, PHILADELPHIA ELECTRIC COMPANY l.

o M

Gr Vice President 1 I

1 1

l l

7_,

g.

A !

I- ~ COMMONWEALTH OF PENNSYLVANIA .

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,: ss.

COUNTf.OF PHILADELPHIA- : ,,

I J. W. Gallagher, being first duly sworn, deposes and says:- j l i l

3 .i That he is Vice President of Philadelphia Electric Company,- '

l i

the Applicant herein; that he has read the fo'regoing Application <, '

j for' Amendment of Facilit.y Operating Licenses, and 'knows the l 1 's l

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, contents thereof; and that the statements and matters set forth .;

therein are true and correct to the best of his knowledge,

< information and belief. i

.t i

! % k) W D:uh e y -'

j Vice President [

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l 1 r 3

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l 1

Si)bscribed and sworn to j before me this'I* day I i

of serr , 1988. i' 4 W1 , t ol fu i

t U Notary Public JIJOffM Y.PMesse 1

b orvPu%e,fN o.,Phas.Co.

1 " i % 78.1M1

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ML20154D191

Text

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