ML18054B109
| ML18054B109 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/13/1989 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18054B110 | List: |
| References | |
| TAC-72959, NUDOCS 8911220171 | |
| Download: ML18054B109 (11) | |
Text
consumers Power Kenneth W Berry Director POWERIN& Nuclear licensing MICHl&AN'S PRO&RESS General Offices: 1945 West Parnell Road, Jackson, Ml 49201 * (517) 788-1636 November 13, 1989 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
TECHNICAL SPECIFICATIONS CHANGE REQUEST -
ELECTRICAL SYSTEMS (TAC NO. 72959)
Enclosed is a request for change to the Palisades Technical Specifications.
This change request revises the Palisades T~chnical Specification$ to incorporate new requirements into Section 3.7, Electrical Systems.
Facility Change 800 (FC-800), "Off-Site Power Reliability Modification", was undertaken as a response to a loss of off-site power that occurred at the Palisades Plant on July 14, 1987 and to implement the requirements of the recently issued Station Blackout rule, 10 CFR 50.63. Consumers Power Company commitments associated with both of these items involved modifications to incorporate an additional independent source of off-site power.
FC-800 modifies the Palisades Plant electrical configuration to incorporate a third source of off-site power to improve the reliability of the off-site power supply to the Plant and to enhanc~ plant conformance to General Design Criteria, 17 of Appendix A to 10 CFR 50. This modification provides for two immediate and one delayed access off-site power circuits as compared to the one immediate and one delayed access circuits presently provided.
Consumers Power Company letter of April 27, 1989 forwarded a copy of the safety evaluation performed for this modification.
Incorporation of the third source of off-site power will be completed during the 1989 Palisades Maintenance outage. Approval of this change request is not required for start-up following this outage as the plant will be operated by using the most conservative requirements of the existing Technical Specifications and of this change request. The more conservative portions of this change request and administrative controls will specifically prohibit powering the Class IE buses from station power transformer 1-2 during power operation until the amendment to the Plant operating license is approved.
This additional restriction is being imposed due to modifications made to the protective relay logic as part of FC-800. The changes to the relay logic_,,, ~
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Regulatory Commission 2 P~lisades Nuclear Plant TSCR - Electrical Systems November 13, 1989 scheme are described in Consumers Power Company letter dated April 27, 1989, "Response to Request for Additional Information on Modification to Improve Offsite Power Reliability (TAC No 729~9)."
In addition to the changes associated with FC-800, this Technical Specifications change request also provides for an increase in the minimum amount of fuel oil required to be available for the plant diesel generators.
The increase in the required fuel oil capacity, from 16,000 to 21,500 gallons, will insure that the Plant has a seven day fuel oil supply on hand at all times.
Consumers Power Company requests that the effective date of thi$ change be no
~~* sooner than 30 days after the date of issuance of the Amendment.
Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachments OC1189-0005-NL02
- r!J CONSUMERS POWER COMPANY Docket 50-255 Request for Change to the Technical Specifications License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specification~ contained in the Provisional Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on October 16, 1972,* for the Palisades Plant be changed as described in Section I below:
I. Changes A. Change Specification 3. 7 .1. a to r.ead as follows:
"Two physically independent circuits between the off-site transmission network and the on-site Class lE distribution system via the following transformers:
- 1. Safeguards Transformer 1-1
- 2. Startup Transformer 1-2" B. Delete Specification 3.7.1.b C. Change Specification 3.7.2.a to read as follows:
"With less than two of the required off-site power circuits available, operation may continue for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> provided the operation of both diesel generators is demonstrated immediately.
Continued operation beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is permissible provided that capability exists to backfeed power to the Class lE buses via the delayed access circuit.* (Station Power Transformer 1-2) and provided that a report is sent to the NRC immediately with an outline of the plans for restoration and the additional precautions to be taken while the circuit is out of service."
D. Delete Specification 3.7.2.b E. Delete the first three paragraphs of the Section 3.7 Basis and replace with the following.*
"The A.C. power system consists of two off-site power sources (preferred power) and two on-site standby power sources (diesel
- gerierato~ units).
The design of the A.C. power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems. Two independent circuits between the off-site transmission network and the on-site Class lE distribution*
system and two independent standby diesel generators are normally OC1189-0005-NL02
2 required: These ensure availability of the required power to shutdown the reactor and maintain it in a safe .shutdown condition after an anticipated operational occurrence or a postulated design basis accident.
The on-site A.C. safeguards power system consists of two independent 2.4 kv ESF distribution systems with their respective 480-volt load centers and motor control centers, and the 120-volt preferred A.C. po~er system. Each 2.4 kv ESF bus is normally connected to off-site power via Safeguards Transformer i-1. Upon loss of this preferred source to the 2.4 kv ESF buses, a fast transfer to an alternate pref erred source of power (Startup transformer 1-2) is provided. Upon loss* of both immediate access off-site power sources, the ESF buses are energized from the diesel generators. Bus load shedding, transfer to the diesel generatoy )
3 and energization of critical loads are performed automatically.
Capability* is provided to restor*e off-site power via the delayed access off-site power circuit (Station Power Transformer 1-2).
With Safeguards Transformer 1-1 out of service, capability is provided to connect the 2.4 kv ESF buses to Station Power.
Transformer 1-2. When connected to Station* Power Transformer 1-2 a reactor and/or geperator trip will result in a fast transfer of ESF loads to the startup source (Startup Transfo!Iller 1-2).
Continued operation beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with one of the independent off-site circuits out of service is based on the capability provided for backfeeding the Class lE buses via the delayed access circuit (Station Power Transformer 1-2). The design of the delayed access circuit allows for establishing this source of supply within one hour. The Station Blackout coping duration, determined in compliance with 10CFR50.63, has been established as four hours.
Thus, the one hour time period required to establish the delayed access circuit provides that this circuit would be available in sufficient time, following a loss of all on-site AC power supplies and the other off-site AC power circuits, to assure that specified acceptable fuel design limits and design conditions of *the reactor coolant pressure boundary are not exceeded."
F. Change Specification 3. 7 .1. i to read as follows:
"Both diesel generators, with a minimum of 2500 gallons of fuel in each day tank and a minimum of 21,500 gallons of fuel in the underground storage tank~"
G. Change Section 3.7 Basis, paragraph eight to read as follows:.
"The 24,000 gallons total in the storage tank and the day tank will supply one diesel generator for a minimum period of 7 days assuming accident loading conditions and fuel conservation oc11a9..:0005-NL02
3
. practices. ( 5 ) It is recognized that both diesel generators would start during most accident conditions increasing the initial rate of fuel cons.umption. With actions to conserve fuel initiated*
after an assumed delay of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, however, the volume of fuel available to support diesel generator operation is still considered adequate. It is considered incredible not to be able.to secure fuel oil from one of several sources within a radius of 70 miles in less than three days under the worst of weather conditions."
H. Delete FSAR References 2 and 4.
II. Discussion The Palisades plant is currently being modified to incorporate a third source of off-site power to improve the capability for reliable power
- and to enhance conformance to General Design Criteria 17 of 10CFR50.
This modification will provide for two immediate and one delayed access circuits as compared to the one immediate and one delayed access circuits presently provided. For the discussions which follow, refer to the simplified diagram of the Palisades modified off-site power system shown in Figure 1.
The switchyard is common to each.of the preferred off-site power circuits. The switchyard uses a breaker and one-half design with two 345 kv buses. Each of the immediate access circuits is connected directly to one of the switchyard buses whereas the delayed access circuit is capable of being powered from either bus. Each bus can also be powered by ati incoming line from the grid.
The first immediate access circuit consists of a 345 kv to 2400 volt transformer (Safeguards Transformer 1-l) located in the switchyard. The high side of.this transformer is connected to the "F" switchyard bus through a motor operated disconnect switch. The low side of the trans-former is connected to a switchgear house located within the plant protected area. Connections between the transformer and switchgear house are provided via direct buried cable along the route between the switchyard and protected area. This cable is buried beneath the towers carrying the other immediate and delayed access circuits to provide for physical separation. The switchgear house is provided to allow for selection of this immediate access circuit or the delayed access circuit (Station Power Transformer 1-2) as the source of power to the Class lE 2400 volt buses.
- The second immediate access circuit consists of a 345 kv transmission line*between the switchyard and plant site and a 345 kv to 2400 volt transformer (Startup Transformer 1-2) located within.the plant protected area. The high side of this transformer is connected to the "R" switch-yard bus through a motor operated disconnect switch. The low side of the transformer is connected directly to the 2400 volt Class lE bus incoming breakers via bus duct.
OC1189-0005-NL02
4 Off-site power to both 2400 volt Class IE buses is normally provided via the firs.t immediate access. circuit powered from the switchyard "F" bus.
Upon loss of this circuit, a fast transfer is provided to the second immediate access circuit powered by the switchyard "R" bus. The proposed Technical Specification is written to require that both immediate access circuits normally be available. Provisions in the proposed Technical Specification allow for continued operation with one of the immediate access circuits inoperable, provided that the delayed access circuit remains operable. The proposed Technical Specification further requires that the NRC be informed of the decision to operate with one immediate access circuit inoperable. Operation with one immediate and one delayed access circuit available is consistent with the original licensing basis of the plant. The delayed access circuit .can be placed in service within the time constraints established by .the Station Blackout (SBO) coping assessment.
The delayed access circuit consists of one 345 kv transmission line, the 345 kv to 21 kv main transformer #1, 21 kv isophase bus ducts and the 21 kv to 2400 volt Station Power Transformer 1-2. The low side of the 2400 volt transformer is connected to the switchgear house via an enclosed conduit bank. The switchgear house also provides for connection to the first immediate
. access
. circuit and allows for selection
. of the first immediate access circuit or the delayed access circuit as the source of power to the Class IE 2400 volt buses. Switchyard p.ower via the delayed access circuit can be provided from either of the two switchyard buses.
Power can also be provided directly from the grid via .Consumers Power Company's interconnection with the Indiana and Michigan Power Co (Cl).
The delayed accesh*}ircuit is established by opening a motor operated disconnect switch located in the isophase bus between the generator and main transformer. Opening this switch allows for backfeeding via the. main and station power transformers following the operation of other switchyard and in-plant breakers. The time required to perform these operations would be less than one hour. As stated in Consumers Power response to the Station Blackout Rule, 10CFR 50.63, dated April 17, 1989, the SBO coping duration for Palisades was determined to be four hours. The one hour time period required to establish the delayed access circuit thus provides that this circuit will be available in sufficient time, following a loss of all on-site AC power supplies and the other immediate off-site power circuits, to assure that specified acceptable fuel design limits and design conditions of the rea.ctor coolant pressure boundary are not exceeded.
In the event that the. first immediate access circuit (Safeguards Trans-former 1-1) were out of service, power to the Class IE buses would be provided by second immediate access circuit (Start-up Transformer 1-2). In the unlikely event that the startup circuit were unavailable, the delayed access circuit would be established by opening the motor operated disconnect switch in the isophase bus and backfeeding via the main and station power transformers as described above.
OC1189-0005-NL02
5 \
(1) The delayed .access circuit is currently established by opening bolted disconnect links in the isophase bus. These links can be opened within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Installation of the. motor operated disconnect switch described here will be completed by the end of the 1990 refueling outage.
In the event that the second immediate access circuit (Startup Trans-former 1-2) were out of service, power to the Class IE buses would continue to be provided by the first immediate access circuit (Safeguards Transformer 1-1). In the unlikely event that power were lost to this circuit, the delayed access circuit would be established by opening the motor operated disconnect switch in the isophase bus and backfeeding via the main and station power transformers as described above.
The changes proposed to each section of the Technical Specifications to incorporate the additional source of off-site power are further discussed in the following paragraphs.
A. This proposed change adds a requirement to provide for two physically independent off-site power circuits. The content of this change is consistent with the Combustion Engineering Restruc.tured Standard Technical Specifications for operating A.C. sources. The transformer designations have been added to uniquely identify the off-site power circuits required.
B. This proposed c11ange deletes Specification 3.7.1.b. All requirements on the availability of off-site power circuits have been incorporated into specification 3.7.1.a and 3.7.2.a.
C. This proposed change adds action requirements in the event that one*
of the circuits required by section 3.7.1.* a is not operable. The action statement allows for continued operation for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
- for this condition. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time period selected for the action statement exceeds the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time period currently provided in the Technical Specifications. Use of a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period is. based on guidance provided in Regulatory Guide 1. 93, "Availability of Electric Power Sources", which has previously been found acceptable by the Regulatory Staff.
With one immediate off-site power circuit inoperable, contl'nued operation beyond the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> restoration period may be allowed provided that the delayed access off-site power circuit remains operable. In order to continue operation in this mode, the proposed change requires that a r~port be provided to the NRC providing plans for restoration of the circuit which is out of service and providing details of the additional precautions to be taken while the circuit is out of service. Operation with one immediate access and one delayed access off-site power *circuit available is consistent with the original licensing basis for the plant.
OC1189-0005-NL02.
., 6 Operation with less than one immediate and one delayed access circuit operable would be limited by the requirements of Specification 3.7.2.
This specification requires that the plant be placed in hot standby within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> if the requirements of Section 3.7.1 *s modified by the 3. 7. 2 action statements cannot be met. '
D. This proposed change deletes Specification 3.7.2.b. All requirements on the availability of off-site power circuits have been incorporated into Specification 3.7.1.a and 3.7.2.a.
E. Changes to the Basis section of the Electrical Systems Technical Specification incorporates information related to the third source of off-site power~ . Incorporation of the third off-site power source resulted in eliminating the following information from the Basis:
- 1. Reference to a spare 345/21 kv transformer and other mobile
.transformers was deleted. Incorporation of the third source of off-site power eliminates the need to provide for spare trans- .
formers to backup the standby power sources.
- 2. Reference to the 4160 volt buses powering the primary coolant pumps was deleted. This section of Technical Specifications only addresses requirements for the Class IE power system. The 4160 volt buses are not Class lE.
F. This proposed change increases the minimum amount of diesel fuel oil required to be available in the underground storage tank. This change will ensure that a seven day fuel supply for the emergency diesel generators will be available.
G. Changes to the Basis section related to the fuel oii supply requirements incorporate information supporting the fuel oil supply requirements and the necessary operator action as developed by the Palisades engineering evaluation "Emergency Diesel Generator Load Profile Study."
H. This proposed change deletes references to the FSAR that no longer appear in this technical specification.
III. Analysis of No Significant Hazards Considerations Technical Specifications relating to the electrical systems administra-tively specify the minimum equipment required to be operable for continued plant operation. Incorporation of the new off-site power source into .the Technical S~ecification provides additionar assurance that off-site power will be available for use in the unlikely event of an accident. Incor-porating more stringent requirements on the minimum equipment requirements into Technical Specifications cannot increase the probability of an accident or malfunction of equipment, nor can it create the possibility OC1189-0005-NL02
7 of- an accident n-O"t previously analyzed. Incorporating the -new off-site power source into Technical Specifications may reduce the consequences of an accident as it provides additional assurance the equipment is operable when required.
The proposed Technical Specification allows for connection of the 2.4 kv Class lE_ buses to Station Power Transformer 1-2 in the event that the new Safeguards Transformer 1-1 is out of service. This results_ in operation of the off-site power system in a*manner consistent with present operation with the* exception that the diesel generator starts on Startup Transformer 1-2 undervoltage and subsequent load shed on a reactor or turbine generator trip in conjunction with an undervoltage on Startup Transformer 1-2 have been eliminated. In the original plant design, the undervoltage monitors on Startup Transformer 1-2 were the only under-voltage monitoring devices which would initiate the load shed, diesel
_generator start and load sequence. Subsequent to the original design, two monitors detecting the voltage directly on each of the Class lE 2.4 kv buses were incorporated. These new voltage monitoring schemes for starting the diesel generators, disconnecting the preferred power source and load shedding meet the requirements of IEEE. 741, "IEEE Standard Criteria for the Protection of Class lE Power Systems_ and Equipment in
- Nuclear Generating Stations". Following incorporation of Safeguards Transformer 1-1 as the normal source of power to the 2.4 kv buses, an undervoltage of Startup Transformer 1~2 will no longer be indicative of a loss of off-site power. Thus, the need to start diesel generators and shed loads- on the 2.4 kv buses based solely on undervoltage of the backup startup source is not required when power is provided from the Safeguards Transformer. With Station Power Transformer 1-2 providing power to_the Class lE buses, undervoltage monitoring is provided by detectors connected directly to the Class lE bus as required by IEEE 741. Removal of the diesel generator start and bus load shed sequence presently provided by Startup Transformer 1-2 results in a consistent undervoltage monitoring scheme independent of the source of power to the buses and will not result in a reduction in the level of protection provided by the original plant design.
The current electrical system Technical Specification basis discusses the availability of one immediate access off-site power circuit with a supplemental backup source of power provided by other spare and mobile transformers. The basis states that these spare and mobile transformers could be connected_ within six weeks. Incorporation of a second per-manently installed immediate access off-site power system increases the margin of safety as presently defined by significantly increasing the reliabilit;y of the power _connections between the plant and switchyard.
As an additional source of off-site power has been permanently connected,.
the requirements in the Technical Specification basis related to the
- connection of spare and mobile transformers has been deleted.
OC1189-0005-NL02.
8 IV. Conclusion The Palisades Plant Review Committee has reviewed this Technical Specification Change Request and has determined that this change does not involve an unreviewed safety question and therefore involve*s no significant hazards consideration *. This change has been reviewed by the Nuclear Safety Services Department. A copy of this Technical Specification Change Request has been sent to the Stat-e of Michigan official designated to receive such Amendments to the Operating License.
CONSUMERS POWER COMPANY To the best of*my knowledge, information and belief, the content~ of this Technical Specification Change Request are truthful and complete.
By ;i.:::~~~~_:_:~~~¥:::~::;:::::::::::::::::...:*':.L'/11 '3/Ff Hoffman, e Nuclear Operati Sworn and subscribed to before me this 13th day of November, 1989.
Ldi~
Elaine E Buehrer, Notary Public Jackson County, Michigan My commission expires October 11, 1993 OC1189-0005-NL02
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