ML20196G027

Proposed Tech Specs 4.9.A.8.b Revising Load Value for Diesel Generator to Be Equal to or Greater than Largest Single Load & Revising Frequency & Voltage Requirements During Performance of Test

ML20196G027
Person / Time
Site:	Quad Cities
Issue date:	05/01/1997
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20196G022	List: ML20196G016 ML20196G027
References
NUDOCS 9705130232
Download: ML20196G027 (7)

Text

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,i ELECTRICAL POWER SYSTEMS A.C. Sourc:s - Oswating 3/4.9 A l

! 3.9 - LIMITING CONDITIONS FOR OPERATION 4.9 - SURVEILLANCE REQUIREMENTS sesel or

5. With two of the above required offsite b

• j circuit power sources inoperable: - lity to sts ngle eme y load ( kW)

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i s. Restore at least one of the sintaini ue .3H inoperable offsite circuits to and ge

• j' i OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least HOT SHUTDOWN c. Verifying the diesel generator within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in capability to reject a load between COLD SHUTDOWN within the 2470 and 2600 kW", without following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. See. tripping on ov.r.p..d. The '

iygeri generator voltage shall not exceed 5000 volts'8 during or fotowing the Restore at least two offsite circuits b.

to OPERABLE status within 7 days h. load rejection.

from the time of initial loss or be in at least HOT SHUTDOWN within d. Simulating a loss of offsite power the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD by itself, and:

SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.' 1) Verifying de-energization of the emergency buses, and load shedding from the emergency

6. With both of the above required diesel buses, generator power sources inoperable:

s. Demonstrate the OPERABILITY of

2) Verifying the diesel starts on the offsite circuit power sources by the auto-start signal, energizes performing Surveillance the emergency buses with Requirement 4.9.A.1.s within permanently connected loads in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once per s10 seconds, energizes the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. auto-connected shutdown loads, and operates with this load for 25 minutes. After energization, the steady-state voltage and frequency of the emergency busses shall be maintained at 4160 i420 volts and 60 *1.2 Hz, respectively, during this test.

d Momentary transients outside of the load range do not invalidate this test. Diesel generator loadings may include padualloading as recommended by the manufacturer / vendor. This surveillance shall be conducted on only one diesel generator at a time.

g Momentary transients outside of the voltage limit do not invalidate this test.

• * "7 3/4.9-5 Amendment Nos.

QUAD CITIES - UNITS 1 & 2 9705130232 970501 PDR ADOCK 05000254 P PDR

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INSERT 1 to page 3/4.9-5 (SR 4.9.A.8.b):

b. Verify the diesel generator rejects a load l l ' greater than or equal to its largest single I i emergency load, and: i i

1) Following load rejection, the frequency is  ;

< 66.73 Hz.

2) Within 3 seconds following load l

! rejection, the voltage is 4160 + 420 <

l volts.  !

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l 3) Within 4 seconds following load j l rejection, the frequency is 60 1.2 Hz. )

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ELECTRICAL POWER SYSTEMS B 3/4.9 i ..

BASES 1

1 Surveillance Requirements are also provided for demonstrating the OPERABILITY of the diesel j generators. The specified testing is based on the guidance provided in Regulatory Guide 1.9, Revision 3 (7/93), Regulatory Guide 1.108, Revision 1, and Regulatory Guide 1.137, Revision 1, as j modified by plant specific analysis, diesel generator manufacturer / vendor recommendations and i responses to Generic Letter 84-15.

INSERT The diesel g@enerators are equipped with a prelubrication system which maintain of oil to the diesel engine moving parts while the engine is shutdown. The purpose of this system is to increase long term diesel generator reliability by reducing the stress and wear caused by I' l

_ frequent dry starting of the diesel generator. The diesel generator prelube may be accomplished

aither through normal operation of the installed prelubrication system or by manual prelubrication t

of the diesel generator in accordance with the manufacturer's/ vendor's instructions. Performance '

[ of an idle start of the diesel generator is not considered to be a means of prelubrication.

A periodic " start test" of the diesel generators demonstrates proper startup from standby conditions, and verifies that the required generator voltage and frequency is attained. For this test, l 1

j the diesel generator may be slow started and reach rated speed on a prescribed schedule that is i J

selected to minimize stress and wear. In cases where this Surveillance Requirement is being used l

to identify a possible common mode failure in accordance with the action provisions, this test sliminates the risk of paralleling two of the remaining A.C. sources, which may compromise the

A.C. source independence.

A " load-run test" normally follows the periodic " start test" of the diesel generator to demonstrate operation at or near the continuous rating. This surveillance should only be conducted on one

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diesel generator at a time in order to avoid common mode failures that might result from offsite circuit or grid perturbations. A minimum run time of 60 minutes is required to stabilize engine temperatures. Actual run time should be in accordance with vendor recommendations with regard to good operating practice and should be sufficient to ensure that cooling and lubrication are adequate for extended periods of operation, while minimizing the time that the diesel generator is connected to the offsite source. This Surveillance Requirement may include gradualloading, as recommended by the manufacturer, so that mechanical stress and wear on the diesel engine are minimized. A load band is provided to avoid routine overloading of the diesel generators.

Momentary transients outside the load band because of changing bus loads do not impact the validity of this test.

A periodic surveillance requirement is provided to assure the diesel generator is aligned to provide standby power on demand. Periodic surveillance requirements also verify that, without the aid of

< the refill compressor, sufficient air start capacity for each diesel generator is available. With either pair of air receiver tanks at the minimum specified pressure, there is sufficient air in the tanks to start the associated diesel generator.

1 The periodicity of surveillance requirements for the shared diesel generators shall be equivalent to .

i those required for the unit diesel generators. For example, it is not the intention to perform surveillances for the shared diesel generators twice during the specified surveillancti interval in order to satisfy each unit's diesel generator surveillance requirements. By appropriately staggering i

B 3/4.9-3 Amendment Nos. 17 a 167 1

QUAD CITIES - UNITS 1 & 2

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INSERT 2 to page B 3/4.9-3:

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! Surveillance Requirement 4.9.A.8.b demonstrates the diesel generator load response characteristics and capability to reject the largest single emergency load while maintaining a specified margin to the overspeed trip. Each diesel generator is provided with an engine overspeed trip to prevent damage to the engine. Recovery from the transient caused by the loss of a large load could cause diesel engine overspeed, which, if excessive, might result in a trip of ,

the engine. The recovery response of the diesel generator will be demonstrated by verification of the steady-state voltage and frequency following the load rejection. The largest single emergency i load associated with each diesel generator is the residual heat removal service water (RHRSW)  !

pump (900 horsepower nameplate). This Surveillance can be accomplished by one of two methods. One method is to simultaneously trip loads supplied by the diesel generator, which have  ;

l l a minimum combined load equal to or greater than the RHRSW pump. The other method is to i trip the RHRSW pump.

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A'ITACHMENT C l SIGNIFICANT HAZARDS CONSIDERATION ESK-97-086 Page 1 of 3 The Commission has provided standards for determining whether a no significant hazards l consideration exists as stated in 10 CFR 50.92(c). A proposed amendment to an operating license involves a no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant .

reduction in a margin of safety.

Comed proposes to amend Appendix A, Technical Specifications 3/4.9.A, "A.C. Sources -

Operating," of Facility Operating Licenses DPR-29 and DPR-30. The purpose of this amendment request is to clarify the Surveillance Requirement 4.9. A.8.b testing criteria and bases.

Comed has evaluated the proposed Technical Specification Amendment and determined that it does not represent a significant hazards consideration. Based on the criteria for defining a significant hazards consideration established in 10 CFR 50.92, operation of Quad Cities Units I and 2 in accordance with the proposed amendment will not:

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

The proposed changes represent a clarification of the intent of the performance of the largest single emergency load rejection surveillance for the diesel generator. These changes allow for simulated testing that will more closely duplicate actual emergency loading conditions. By removing the specific load value requirement from the surveillance, the test can be performed using the actual largest load in the same plant configuration that would exist during an actual accident scenario. Verification of the steady-state voltage and frequency within the required time limits provides confidence that the diesel generator can successfully recover from this transient. This provides greater assurance that the diesel generator is capable of performing its intended design function during an accident and the subsequent recovery. The changes to the surveillance requirement will not significantly increase the consequences of an accident previously evaluated.

The diesel generator's design function is to mitigate the consequences of an accident by providing an independent onsite source of alternate AC power with the capacity for l operation of systems required to shutdown the reactor and maintain it in a safe shutdown I

condition until offsite power is restored. The diesel generator and its associated subsystems are not assumed in any safety analysis to initiate any accident sequence for Quad Cities Station; therefore, the probability of an accident presiously evaluated is not increased by the proposed amendment.

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I ATTACHMENT C SIGNIFICANT HAZARDS CONSIDERATION I ESK-97-086 i Page 2 of 3 l

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

i The proposed changes do not create the possibility of a new or different kind of accident  :

previously evaluated for Quad Cities Station. The changes revise the largest single emergency load rejection surveillance test acceptance criteria for the diesel generator. ,

This load rejection transient for the diesel generator is bounded by a previously performed accident analysis. This analysis assumes the loss of one diesel generator due to loss of125 VDC control power for the duration of a LOCA combined with a LOOP. The  !

diesel generator's design function is to mitigate the consequences of an accident by providing an independent onsite source of alternate AC power with the capacity for operation of systems required to shutdown the reactor and maintain it in a safe shutdown condition until offsite power is restored. Only one diesel generator is required to perform this function per unit. Performance of the Surveillance Requirement as proposed provides greater assurance that the diesel generator is capable of performing its intended design function during an accident and the subsequent recovery. No significant changes to existing testing or new modes of facility operation are proposed by this change. The proposed changes maintain at least the present level of operability. Therefore, the i

proposed changes do not create the possibility of a new or different kind of accident from l

any previously evaluated. '

3) Involve a significant reduction in the margin of safety because:

The proposed amendment is required to ensure the diesel generator is tested in accordance with the design basis requirements. The changes represent a revision to the test acceptance criteria for performance of the largest single emergency load rejection surveillance for the diesel generator. This is a possible transient for the diesel generator that is bounded by a previously performed accident analysis. The proposed changes do not adversely affect the capability of the diesel generator to perform its design function. 1 This function is to mitigate the consequences of an accident by providing an independent onsite source of alternate AC power with the capacity for operation of systems required to shutdown the reactor and maintain it in a safe shutdown condition until offsite power is restored. Performance of the Surveillance Requirement as proposed provides greater '

assurance that the diesel generator is capable of performing its intended design function during an accident and the subsequent recovery. Existing plant safety margins or the reliability of the equipment assumed to operate in the safety analysis are not changed. The proposed changes have been evaluated at Quad Cities and found to be acceptable for use l based on system design, safety analysis requirements and operational performance. Since the changes maintain the necessary levels of system reliability, the proposed changes do not involve a significant reduction in the margin of safety.

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, ATTACHMENT C SIGNIFICANT HAZARDS CONSIDERATION ESK-97-086 Page 3 of 3 '

The proposed amendment for Quad Cities Station will not reduce the availability of  ;

systems required to mitigate accident conditions. The proposed changes will not effect  ;

any planned or postulated releases of radioactive materials from the facility. Therefore, i the proposed changes do not involve a significant reduction in the margin of safety. .

Guidance has been provided in " Final Procedures and Standards on No Significant Hazards Considerations." Final Rule 51 FR 7744, for the application of standards to license change  !

requests for determination of the existence of significant hazards considerations. This document provides examples of amendments which are and are not considered likely to involve significant i hazards considerations. This proposed amendment does not involve any irreversible changes, a significant relaxation of the criteria used to establish safety limits, a significant relaxation of the l

bases for the limiting safety system settings or a significant relaxation of the bases for the limiting i conditions for operations. Therefore, based on the guidance provided in the Federal Register and the criteria established in 10 CFR 50.92(c), the proposed change does not constitute a significant hazards consideration.

ENVIRONMENTAL ASSESSMENT  !

Comed has evaluated the proposed amendment against the criteria for identification oflicensing i and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.21. It has been determined that the proposed changes meet the criteria for a categorical exclusion as  !

provided under 10 CFR 51.22(c)(9). This conclusion has been determined because the changes requested do not pose significant hazards consideration, involve a significant increase in the ,

amounts, or significant changes in the types of any effluents that may be released off-site.

Additionally, this request does not involve a significant increase in individual or cumulative occupational radiation exposure. I l

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