ML20044E001
| ML20044E001 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1993 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | |
| Shared Package | |
| ML20044D997 | List: |
| References | |
| NUDOCS 9305210174 | |
| Download: ML20044E001 (6) | |
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METROPOLITAN EDISON COMPANY JERSEY CENTRAL POWER & LIGHT COMPANY AND PENNSYLVANIA ELECTRIC COMPANY THREE MILE ISLAND NUCLEAR STATION, UNIT 1 Operating License No. DPR-50 l
Docket NO. 50-289 l
Technical Specification Change Request-No. 221 i
t COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF DAUPHIN
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i This Technical Specification Change Request is submitted in support of j
Licensee's request to change Appendix A to Operating License No. DPR-50 for t
Three Mile Island Nuclear Station, Unit 1.
As part of this request, proposed i
replacement pages for Appendix A are also included.
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GPU NUCLEAR CORPORATION I
BY:
bb VicePresidegandDirector,TMI-l l
l Sworn and Subscribed to before me i
this 17th day of May
, 1993.
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION IN THE MATTER OF DOCKET NO. 50-289 GPU NUCLEAR CORPORATION LICENSE N0. DPR-50 CERTIFICATE OF SERVICE This is to certify that a copy of Technical Specification Change Request No. 221 to Appendix A of the Operating License for Three Mile Island Nuclear Station Unit 1, has, on the date given below, been filed with executives of Londonderry Township, Dauphin County, Pennsylvania; Dauphin County, Pennsylvania; and the Pennsylvania Department of Environmental Resources, Bureau of Radiation Protection, by deposit in the United States mail, addressed as follows:
Mr. Darryl LeHew, Chairman Mr. Russell L. Sheaffer, Chairman Board of Supervisors of Board of County Commissioners Londonderry Township of Dauphin County R. D. #1, Geyers Church Road Dauphin County Courthouse Middletown, PA 17057 Harrisburg, PA 17120 Director, Bureau of Radiation Protection PA. Department of Environmental Resources Fifth Floor, Fulton Building Third and Locust Streets P. O. Box 2063 Harrisburg, PA 17120 Attn: Mr. Richard R. Janati i
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GPU NUCLEAR CORPORATION BY:
Vice President (And Director, TMI-I DATE:
May 17, 1993 i
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C311-93-2064 f
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TECHNICAL SPECIFICATION CHANGE REOUEST (TSCR) NO. 221 GPUN requests that the following changed replacement pages be inserted into the existing Technical Specifications (TS):
Revised pages:
3-28 and 3-32a II.
REASON FOR CHANGE The change is requested to:
1.
Clarify required action if the degraded voltage timer or loss-of-voltage timer is inoperable.
2.
Provide action requirements for the low voltage relays that are consistent with similar safety components.
l 3.
Delete the requirement to place an inoperable relay in a tripped state within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The requirement to trip the failed degraded grid relay is deleted because this action prevents function of the associated block loading i
timer.
III.
SAFETY EVALUATION JUSTIFYING CHANGE Twelve solid-state undervoltage relays are installed in two groups of l
three on both the D and E 4160 volt engineered safeguards (ES) buses.
These relays protect the safety-related loads from a loss of power and i
from a sustained degraded voltage on the offsite electric grid system.
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Protection against a loss of Offsite Power (LOOP) event is provided by three relays; each set at 2400 volts, arranged in a two out of three l
logic and set to trip if voltage falls below 2400 volts for 1.5 l
seconds. The voltage trip setpoint and timer setting were chosen to correspond with conditions expected during a LOOP event.
l Similarly, protection against degraded grid conditions is provided by the second group of three relays. These relays are also arranged in a i
two out of three logic and are set to trip if voltage drops below 3760 l
volts for 10 seconds. The voltage trip and timer setpoints correspond l
with conditions expected from a degraded grid. Unnecessary separation l
from offsite power during transient events is prevented by time delay.
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The degraded grid relays prevent overheating or spurious tripping of l
safety related loads from low voltage.
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C311-93-2064 l
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A 4160 volt ES bus will automatically trip and the associated diesel generator will start when low voltage is detected which satisfies the trip logic of either group of relays. The two groups of relays for each bus are independent.
i Current TS require the implementation of Specification 3.0.1 (commence shutdown within one hour) if two relays for either feature are inoperable. The operability requirement applies the action requirement in the same manner as that applied for the ESAS analog
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channels. Treating the undervoltage relays in this manner is j
inappropriate because of the design differences between an ESAS type l
system design and that of the D and E busses.
In the case of the ESAS analog channels, one channel is common to both trains and inoperability impacts both simultaneously. With the D and E busses and the undervoltage relays, a separate set of undervoltage relays is provided for each train and inoperability of a relay impacts only the i
singla train which it protects.
The time being proposed for repair of an inoperable undervoltage relay by this TSCR is consistent with the time allotted for repair of other j
safety. related equipment similarly configured such that only one train i
is affected.
l TS Table 3.5.1, Section C, Footnote e requires placing a failed relay in a tripped state within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Tripping a degraded grid relay i
disables the associated ESAS block loading timer until the diesel breaker closes.
If offsite power is available, this action results in an unnecessary reduction in redundancy of the ESAS logic. The block
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loading timers are designed to function if either offsite power or i
diesel power is available.
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The probability of a degraded voltage or loss of power coincident with I
a design basis event is very low.
It is sufficiently low, that i
allowing appropriate time based on other TS precedent for corrective action, it does not result in an undue risk to public health or j
safety.
In addition, requiring a shutdown before corrective action can be taken does not significantly improve safety and may be, in the larger context, an inappropriate action'if being performed solely i
because of this feature. Absent a design basis event, there is i
sufficient time for manual action to trip the bus and start the diesel in the event the relays are unavailable. The operator would be made aware of degraded offsite power condition by Control Room alarms that are independent of the relays in this specification.
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IV.
NO SIGNIFICANT HAZARDS CONSIDERATIONS GPUN has determined that this Technical Specification Change Request involves no significant hazards consideration as defined by NRC in 10CFR50.92.
i 1.
Operation of the facility in accordance with the proposed amendment would not involve a significant increase in the probability of occurrence or the consequences'of an accident previously evaluated..The proposed amendment permits time to r
restore the relays to operable status that is consistent with times allowed for outage of other safety related equipment affecting one train. The proposed amendment maintains a high i
degree of equipment availability without requiring unnecessary initiation of a plant shutdown for partial equipment outages.
j 2.
Operation of the facility in accordance with the proposed i
amendment would not create the possibility of a new or different i
kind of accident from any accident previously evaluated. With offsite power available, load shedding to limit loading on the j
safety related bus is initiated by the ES signal; therefore, the undervoltage relays perform no function unless offsite voltage becomes unacceptably low.
If an accident-occurred while the i
relays were inoperable, the redundant train would complete the' safety function. The proposed time allowed.for the relays to be out of service is bounded by the allowable time for the diesel to be out of service and is consistent with all.owable outage times for other ES components. Therefore, the proposed amendment does not create the possibility of a new or different accident.
3.
Operation of the facility in accordance with the proposed amendment does not involve a significant reduction in a margin of safety. As noted in the basis for the specification, every t
reasonable effort is and will continue to be made to maintain all I
safety instrumentation operable.
If relays are found to be inoperable or require maintenance to assure their reliability, the proposed amendment will allow the performance of maintenance in a reasonable time period.
Allowing the relays to be out of service creates a vulnerability to incomplete safety function actuation or initiation if a failure occurs in the alternate train._ The concern applies only for events accompanied by degraded offsite power. This change 3
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C311-93-2064 i
i does not result in a significant reduction in the margin of safety because the extension in outage time allows only one train to be affected.
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IMPLEMENTATION t
It is requested that the amendment authorizing this change become j
effective upon issuance.
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