ML20116A890
| ML20116A890 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 10/19/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20116A881 | List: |
| References | |
| NUDOCS 9210300197 | |
| Download: ML20116A890 (13) | |
Text
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jo UNITED ST ATES
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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 119 TO FACILITY OPERATING LICENSE NO. DPR-19.
AMENDMENT NO 115 TO FACILITY OPERATING LICENSE NO. DPR-25.
AMENDMENT N0.138 TO FACILITY OPERATING LICENSE NO. DPR-21 bND AMENDMENT NO.
34 TO FACILITY OPERATING LICENSE NO. DPR-30 COMMONWEALTH EDISON COMPANY blQ IOWA ILLIN0IS GAS AND ELECTRIC COMPAN'(
DRESDEtL!Ly((fAR POWER STATLON_UNUS 2 AND 3 DLLAD CITIES NUCLEAR POWER STATION. UNITS 1 AND 2 DOCKET NOS. 50-237. 50-249. 50-254. AND 50-265
1.0 INTRODUCTION
Technical Specification Section 3/4.9 provides the requirements for Dresden l
and Quad Cities Gtation's " Auxiliary Electrical Systems." These requirements provide assurance that an adequate supply of electrical power is available to the plant during operating, shutdown, and everyday conditions.
The equipment encompassed by this specification are the incoming (off-site) transmission lines and associated switchgear, the station batteries, the emergency diesel generators, and the in-plant AC buses important to reactor safety.
In a submittal dated June 29, 1992, as supplemented August 28, 1992, I
Commonwealth Edison Company, (the licensee, CECO) proposed changes to Section l
3/4.9 of Technical Specifications (TS) for the Dresden and Quad Cities i
Stations.
The primary purpose of the proposed chances is to:
(1) revise the i
operability requirements for a diesel generator when performing preventive maintenance and surveillance; (2) revise the requirements for operability of a diesel generator upon loss of other auxiliary electrical equipment; (3) revise the 125 volt DC battery availability requirements to address the use of and inclusion in the TS of the alternate 125 volt DC batteries; and (4) revise the battery testing requirements to include both service and performance test surveillance requirements that reflect current industry standards.
In addition, other proposed TS amendment changes include:
(1) the elimination of redundant errergency core cooling systems testing associated with the operable diesel generator; (2) deletion of a Dresden requirement associated with electrical power availability that necessitates having the reactor vessel 9210300197 921019 PDR ADOCK 05000237 P
.- head off:-(3)- deleting the exemption from declaring the diesel L.nerator inoperable for a period not to exceed 1-1/2 hours for the purpose of conducting preventive maintenance; (4) modifying the current-Quad Cities TS electrical backfeed requirements to be less prescriptive with regard to the second source of power available from the other unit; and (5) various administrative changes primarily associated with the above changes.
The acceptability of these proposed changes of Dresden, Units 2 and 3,-and Quad Cities, Units 1 and 2, is addressed in this safety evaluation.
2.0 EVALUATION 2.1 Diesel Generators (D/G1 l
The licensee has proposed changes to TS Section 3/4.9 related to the D/G for Dresden and Quad Cities.
Specific changes proposed are related to monthly surveillance testing, operability requirements upon loss of offsite power, demonstration of operability of the alternate D/G when a D/G is found inoperable, and the treatment of surveiliance testing as it relates to D/G operability in a manner similar to that of preventive maintenance. Most of the9 proposed changes are the result of, or related to, a concern identified by thr Dresden resident inspectors -that Dresden did not declare the D/G inoperacle when preforming preventive maintenance testing, surveillance testing or operability tests that required synchronizing and loading of the D/G to the grid, shese concerns were discussed in teleconferences between the NRC staff and th? licensee (including both the Dresden and Quad Cities Si
'ons) on April 1, and 15, 1992.
In a letter dated April 24, 1992, Ceco d-aented the results of these teleconferences which included TS erpretations that were found.to be acceptable to the NRC staff on an interim basis.
In this letter Ceco also stated that both the Dresden and Quad Cities Stations' TS are in the process of being modified to address this issue.
The proposed TS contained in this submittal fulfill the licensee's commitment and fully address the staff concerns.
The specific changes are discussed and evaluated below.
2.1.1 Monthlv_ Surveillance Testina l
Current TS 4.9.D.1 at Dresden and 4.9.A.1 at Quad Cities, respectively, presents the monthly operability test requirements for the diesel generators.
The surveillance requirement specifies that each diesel generator shall be started and loaded each month to demonstrate operational readiness, and that the duration of each surveillance shall be sufficient to ensure that both the diesel engine and the generator have achieved equilibrium temperature conditions wh" : full load output is maintained.
The licensee's TS separates the start test and its acceptance criteria from the portion of the test which requires synchronizing the generator to the grid, loading the diesel generator, and running it for an extended period.
lhis separation simplifies reference to these individual portions of the testing and does not change the actual test requirements.
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. grid, loading the diesel generator, and running it for an extended period.
This separation simplifies reference to these individual portions of the testing and does not change the actual test requirements.
The diesel generator units at Dresden and Quad Cities are not equipped with instrumentation for the monitoring of stator temperattre as this was not a standard feature offered by the manufacturer.
Currently, the monthly operability surveillance requires full lcad to be maintained on the diesel generator until equilibrium temperature conditions are achieved.
The proposed specification requires the diesel generator to run fully loaded for a minimum of one hour.
The time duration specified by,the surveillance to achieve equilibrium temperature conditions for the diesel engine has been demonstrated as sufficient by past tests and exceeds the recommended time frame (45 to 50 minutes) provided by the vendor.
The staff has reviewed these proposed changes for Dresden and Quad Cities and determined that it is acceptable to separate the start test aad its acceptance criteria from the portion of the test whl.h_ requires synchronizing.the generator to the grid and loading the-D/G.
As a result of staff-concerns related to D/G operability previously discussed, the need to run the D/G synchronized to the' grid and loaded is not always necessary. The performance of a start test under some conditions, that will be addressed later,-is all that is necessary.
The proposed TS also identifies the correct parameters, rated voltage and frequency to determine operability for a start test.
The proposed TS change states that a monthly operability surveilltace test will be performed with the D/G synchronized and fully loaded for at least one hour, Since this is consistent with the D/G vendor's recommendations and the Standard Technical-Specifications (STS), the staff finds this acceptab'e.
2.1.2 Operability Reouirements Current Specification 3.9.B at Dresden and 3.9.C.3.9.E at:Quaa Cities, respectively, provides two conditions under which a D/G must be operated following the discovery of inoperable or unavailable equipment.
The licensee proposed revisions for this required D/G operation as a result of..the inoperability or unavailability of other equipment._ These include:
(a)- revising the requirement for operating the D/G upon loss of the two incoming offsite power lines, (b) revising the requirement for the demonstration of operability of the alternate diesel generator when a D/G is found inoperable, or (c) when making a D/G inoperable for the performance of pre planned preventive maintenance to include surveillance testing.
u The current TS requires that upon los31of both incoming offsite pov:er lines the diesel generators must be " operating." The manufacturer does not recommend the diesel generators to be operated at no load for long periods of time, so the diesel generators are synchronized and loaded in this situation.
While connected to the bus, the diesel generators are vulnerable to a load transient should the turbine generator of the unit trip.
To eliminate this vulnerability and enhance the availability of the diesel generators, the
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. t licensee's proposed TS requires the diesel generatcrs to be " demonstrated operable" rather than " operating," A similar vulnerability exists if the alternate diesel generator is demonstrated operable by starting and loading following the loss of one diasel generator in accordance with current TS 3.9 B.2.a for Dresden and 4.9.E.1 at Quad Cities, respectively.
The proposed TS require the alternate diesel generator to be demonstrated operable by conducting a start test only.
The vulnerability of the D/G will be eliminated if the required demonstration does not require a subsequent synchronizing and loading.
Currently, Specification 3.9.B.2,b/3.9.E.2 (Dresden/ Quad Cities) allows D/G to be made inoperable for a period of 1-1/2 hours for the purpose of preventive maintenance; however, an operability demonstration on the alternate diesel generator is required prior to the performance of the maintenance activity.
Therefore, a pre-planned, short duration D/G outage for the purpose of preventive maintenance currently results in additional D/G operability demc,nstrations (for the alternate D/G).
With the current rvuirements, station implementation cf INPO (and vendcr} recommended practices, intended to reduce the potential for damage to a diesel engine during starts, is impractical, in accordance with the recommended practice, a D/G would be msnually rotated, or " barred", one revolution prior to each routine start (i.e., starts not resulting from the inoperability of other AC auxiliary 3
electrical power equipment), in order to cl uk for fluid in the engine's i
cylinders, For personnel safety during thi., procedure, the automatic start l
capability of the diesel generator needs to be disabled-(by isolating the air I
suppiy to the air start motors), thereby rendering the diesel generator l
Consequently, implementation of this practice with-the current Technical Specifications would result in an additional diesel generator operability demonstration (for the_ alternate diesel generator).
This situation is also described cn a general basis in Information Notice 91-62.
In the licensee's proposed change, a D/G would be declared inoperable and-the normal allowed out-of-service time of seven days would be applied for the-purposes-of conducting pre-planned preventive maintenance or surveillance p
testing.
However, in keeping with the reduction of unnecessary starts on the l
emergency D/G, and since these. pre-planned preventive _mainten.ance or L
surveillance testing activities are unrelated to potential generic concerns, l
- the operability verification for the alternate D/G will-not be based on-an L
operability demonstration.
The verification of operability as used-in this=
context, means to administratively check by examining logs or other information to determine if components and systems are out-of-service for maintenance or oth_er reasons. This operability verification approach is consistent with the later BWR Technical Specifications (such as Hope Creek, River Bend, and Limerick), 2nd practices for pre-planned diesel generator outages for the purposes of preventive maintenance or testing.
These changes address two of the primary concerns of the NRC staff; the vulnerability of the D/G to a load transient should the turbine generator of the unit trip when the D/G is loaded to the grid, and that under the current
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. TS a D/6 can be made inoperable for a period of 1-1/2 hours for preventive maintenance without declaring the D/G inoperable.
The staff has reviewed the licensee's proposed TS' changes related to testing the D/G when both offsite incoming power lines are lost or one of the D/G is inoperable.
The performance of a start test assures operability of the D/G and eliminates the vulnerability to a load transient if the turbine generator should teip.
The monthly surveillance test of the D/G will be performed with the D/G synchronized and loaded to the grid.
However, the D/G are tested one at a time and this test is needed to assure that the D/G will perform its intended function when loaded.
The probability of an accident occurring, that would result in a commitment loss of offsite power, during the time of the monthly D/G surveillance test is very low. The staff has reviewed these proposed changes and concluded that since the vulnerability of the D/G to fail in the event of a load transient will be eliminated and that the changes are consistent with the BWR STS, they are acceptable.
The staff has reviewed the licensee's proposed TS change and determined that deletion of the current requirement permitting a D/G to be inoperable for a period of 1.1/2 hours for the purpose of preventive maintenance without declaring the D/G inoperable and the substitution of a requirement that a D/G be declared inoperable during pre-planned preventive maintenance or surveillance testing provided the operability of the alternate D/G can be verified administratively, is acceptable.
By the elimination of the 1-1/2 hour grace period the D/G will appropriately be declared inoperabie and the operability verification approach for the alternate diesel both reduces unnecessary starts and is a position the staff has accepted for newer plants.
2.2 US Volt DC Alternatt datteries The 125 volt DC electrical distribution system for each unit consists of two-separate divisions.
These divisions are provided 125 volt _DC power by two battery systems (shared between two' units), each of _ which originally consisted of one 125 volt battery and two chargers.
The normal operating configuration has each 125 volt system-supplying DC power for one of the two 125 volt DC divisions on each unit through the battery chargers.
A safety-related alternate 125 volt battery has been installed for each unit with a primary purpose of supporting the performance of the rated discharge tests on the permanent battery.
The alternate battery is utilized to avoid a reduction in the single failure capacity of the 125-volt system during performance of_the rated Jischarge test in the permanent battery.
The' alternate batteries are of the sam' type (lead-calcium) as the normal 125 volt batteries and_were provided by the same vendor.
The alternate batteries have been sized-to carry the normal DC loads and the required safe shutdown loads as described in the Final Safety Analysis Report (FSAR). Section 8, and the capacity of each battery meets or exceeds that of its-acsociated normal (permanent) battery.
The alternate batteries have been seismically qualified and installed and meets the same requirements as the primary batteries except
e provide the missile protection discussed in FSAR Section 12; however, a r sk i
analysis has shown the probability of a tornado missile event during a full calendar year to be less than 1 E-7 (0.87 E-7) which is below the threshold level where the event is a concern.
For Quad Cities, Unit 2, the alternate battery is located in the turbine building which provides the same protection for Unit 2 alternate battery as a Class 1 structure, except for the case of tornado missiles.
However, a probabilistic analysis has been performed which shows that limiting the period that the alternate battery is relied upon to less than 52 days in any calendar year limits the probability of a tornado missile striking the battery while it is relied upon to less than IE-1.
Commonwealth Edison Company has limited the period that the Unit 2 alternate battery is relied upon to less than 52 days in any calendar year.
There are l
no limitations on the Unit I alternate battery.
In a September 30, 1991, submittal CECO provided a description of the alternate 125 volt DC battery system design and installation.
During the staff review it was determined that the alternate battery system does not nave two disconnect switches on the reserve bus end of the cable connecting the main bus with the reserve bus.
In a submittal dated August 21, 1992, CECO provided a supplement to its June 29, 1992, submittal.
One of the purposes of this supplement was to change the proposed TS related to when the alternate 125 volt DC battery can be used.
In this supplement CECO stated that the original design of the 125 volt DC battery distribution system for Dresden and Quad Cities Stations only included a single manual disconnect switch at one end of the ccble connecting the 125 volt DC reserve bus.
In 1981, an evaluation of the 125 volt DC distribution systems noted that a fire in the main 125 volt DC bus switchgear could f ault the cable used to provide the backup feed to the 125 volt DC reserve bus with the ultimate result that both buses could be disabled.
To address this concern, both Dresden and Quad Cities installed two (2) disconnect switches on the reserve bus end of the cable connecting the main bus with the reserve bus.
Although the alternate 125 volt DC battery system design meets the isolation criteria of the original 125 volt DC system for both Dresden and Quad Cities, it does not include the additional disconnect switches between me reserve bus and main bus.
Due to this design difference Dresden and Quad Cities Stations only propose adding the alternrte battery as a permanent auxiliary method of ensuring plant DC power sources are available in the event that the normal 125 volt DC system is unavailable.
This requirement would be waived for a period up to seven days if the alternate 125 volt DC battery system was placed into service and operable as defined by the applicable surveillance requirements.
The current requirements at Dresden allow the 125 volt DC system to be inoperable for a period of seven days per operating cycle for maintenance or testing.
In addition, Dresden's requirements allow an additional seven days if the battery needs to be replaced due to maintenance or testing.
The current requirements at Quad Cities allow the 125 volt DC system to be inoperable for any reason for a period of three days, l
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i Since the alternate 125 volt DC battery system does not provide the same protection from the consequences of loss of function as specified in Appendix R, during periods when using the alternate 125 volt battery, Ceco has committed to institute administrative controls to reauce the risk of causing a-fault to the system.
In a letter dated October 16, 1992, CECO provided further clarification regarding the administrative controls that will be in place when the alternate battery system is placed in service.
This letter stated that during pariods when the alternate 125 volt battery is placed into service, the circuit breaker that is normally open between the DC-Main Bus (Division I) and the DC Reserve Bus (Division II) shall be administratively controlled open by hanging an out-of-service (005) card (using the appropriate 005 site procedure) on the breaker.
The station procedures that control the process to place into service the alternate 125 volt hattery shall specify that the normally open breaker will be (on the DC reserve BUS Division 2) either placed into the open condition using the appropriate posting of notification / card, follosing the normal 005 procedure or verified to be in the open position (notification / card).
In addition, this letter stated that when the alternate 125 volt battery system is not in service the batteries are physically disconnected from the DC system.
The proposed TS changes that permit use of the alt:raate 125 volt DC battery i
system during operation are as rollows; 1.
With both units operating, each 125 volt battery may be inoperable for up to a' maximum of seven days per operating cycle for maintenance and testing provided the alternate 125 volt battery is placed into service, i
2.
With the other unit in cold shutdown or refuelino, operations may continue with one of the two 125 volt battery E items inoperable provided the alternate 125 volt battery is-plated into service.
3.
If it is determined that a 125 volt battery needs to be replaced as a result-of maintenance or-testing, a specific battery may be inoperable for an additional seven days provided the alternate 125-volt battery is placed into service.
The staff has reviewed the de.ign-of the alternate 125 volt DC battery system and concluded that it is equivalent to the primary battery system except for an additional disconnect switch that was installed to provide protection against a fire in the main 125 volt DC switchgear that could fault the cable and result in disability of both the 1ain and reserve buses.
Commonwealth Edison Company has also evaluated the additional combustible load resulting from alternate battery and its associated cables and concluded it is low and produces little heat due to the low BTU rating.
The alternate battery also does not cross a fire area boundary, is located in an area where fire detectors are present, and any abnormal conditions will be indicated in the 4-Control Room.
in addition, there is a portable CO2 extinguisher suppression
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w 8-system available in the area and the existing fire detection s.r.cem is sufficient for the additional fire loading due to the alternate battery.
The staff has evaluated the proposed TS changes that would permit use of the alterr. ate 125 volt DC battery system and concluded it is acceptable based on the following:
1.
Plant safety and battery reliability are improved by the addition of this system.
2.
The propused limited usage of the alternate battery system results in an improvement in plant safety since the current TS permit continued operation for up to a maximum of 14 days during an vperating cycle with one primary battery system inoperable.
3.
There is a low prob 6ility that a fault would occur, that coul6 disable both the main and reserve bus, durino the limited time period the alternate battery is connacted.
4.
Adequate administrate controls are in place to assure that the circuit breaker between the DC main bus and the DC reserve bus will remain in the normally open position during the use of the alternate battery.
Although the staff finds the limited use of the alternate battery acceptable, to assure that it is not permanently connected and left in place, Ceco should revise the TS Bases of this section to include the reason why only limited use of this battery is permitted and why it should not be permanently connected.
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The Bases section can be revised as part of the TS upgrade program.
2.3 Battery S.ervice and Performance Tests Current Specifications 4.9. A.3 for Dresden and 4.9.B for Quad Cities requires a " rated load discharge test" for the station batteries on a refueling outage frequency. A review of battery testing specifications of other Ceco nuclear units revealed that the LaSalle County Station Technical Specifications for battery service and performance testing closely resembled the testing that the other stations committed to perform. The proposed changes reflect these revised testing requirements.
The current specifications require that a rated l
load discharge test be conducted "every refueling outage" on the batteries.
The proposed specifications for the-service and performaac6 tests are proposed-to be conducted once each operating cycle.
This frequency is the same as each refueling outage but allows the testing to be performed at other times during the operating cycle which may be consistent with safe operation.
Commonwealth Edison Company has adopted the Institute of Electrical and Electronic Engineers (IEEE) Standard 450, 1987 Edition.
Consistent with this standard, Dresden now performs a service test (load profile test) at least once each operating cycle to verify that the battery capacity is adequate to supply and maintain operable the actual or simulated emergency loads for the design duty cycle.
In addition, at least once per 60 months, in lieu of.the
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- 9 battery service test, the unit's batteries will be subjected to a performance discharge test (constant amperage discharge test) to verify that the battery capacity is greater than either 80 percent of the manufacturer's, or the minimum acceptable, battery capacity from the latest revision of the load profile.
For any battery that shows signs of degradation or has reached 85 percent of the service life for the expected application, a performance discharge test of battery capacity will be performed at least once each operating cycle.
Degradation is indicated when the battery capacity drops more than 10 percent of rated capacity from its average on previous performance tests, or is below 90 percent of the manufacturers rating.
The staff has evaluated the licensee's proposed TS change and determined that it results in an improvement over the current TS which only spe My that the unit's batteries shall be subjected to a rated load discharge S t.
Until recently only performance discharge type tests were performea at the Dresden i.nd Quad Cities Stations. With the adaptation of IEEE Standard 450 for testing of the batteries, which is endorsed by the NRC Regulatory Guide 1.129 and the NRC Standard Review Plan, Section 8.3.2, both service life tests and periodic performance discharge tests are performed. The service tests simulates the worst-case load profile that would occur during accident conditions and, therefore, provides assurance that the batteries will perform their function.
The periodic performance test provides assurance that significant battery degradation has not occurred.
Since the curreat TS at Dresden and Quad Cities do not specifically state the type of load discharge test to be performed, the licensee determined that the adaptation of IEEE 450 was at least equivalent to the type of load discharge test previously performed. The submittal of this proposed TS change specifically documents the licensee's commitment regarding the type of tests, testing frequency, and acceptance criteria to be utilized in determining the operability of the batteries. On the bases of the above discussion-the staff has determined that these proposed TS changes are a significant impru ement over the current TS and are, therefore, acceptable.
2.4 Ouad Cities-Redundant ECCS Testina
- Quad Cities also proposes to delete the requirements for demonstrating the operability of all low-pressure core cooling systems and all loops of the containment cooling modes of the RHR system associated with the operable diesel generator.
The proposed verification of operability, as used in this context, means to administratively check by examining logs or other information, to determine if these components anJ systems are out-of-service for maintenance or other reasons.
The requirement for demonstrating operability of the redundant systems identified above for Quad Cities, Units 1 and 2, was nriginally chosen because there was a lack of plant operating history and a lack of sufficient equipment failure data.
Since that time, plant operating experience has demonstrated that testing of the redundant ECCS when one system is inoperable is not necessary to provide adequate assurance of system operability.
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4 The staff has reviewed the proposed TS change related to verification of operability of all the redundant low-pressure core cooling system and all loops of the containment cooling modes of the RHR system associated with the operable diesel generator and concluded it is acceptable based on the following; 1.
Taking the redundant system out of service for testing creates the risk of the second system also failing and in some instances it has been observed that failures of the redundant system are related to the test itself and not an indication that the system would have failed should it have been needed.
2.
Operability of these systems can be sh9wn bv checking records to verify that valve lineups, electricci '%s, and instrumentation requirements have not been changed since the last time the system was verified to be operable.
3.
The current Standard Technical Specifications and more specifically all the technical specifications approved for recently licensed BWR's accept the philosophy of system operability based on satisfactory performance of monthly, quarterly, refueling interval, post-maintenance or other specified performance tests without requiring additional testing when another system is inoperable.
4.
Similar changes have been previously approver
,e Dresden Station (Amendments 107 and 102, dated August 10,
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2.5 Power Reduction Followino loss of Both Offsite lines Dresden Station was requested to address a difference between Dresden and Quad Cities Stations' Technical Specification for action to be taken upon loss of both incoming power lines.
In addition to verifying both diesel generators and the core and containment cooling systems operable, and notifying the NRC within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the precautions and plans for prompt restoration, Quad Cities is also required to reduce power to 40 percent of rated power. This reduction in power is based on the steam bypass capacity of the station and was intended to allow continued reactor operation following a complete loss of off-site power and a subsequent turbine trip.
While it is theoretically possible for a unit to avoid an automatic shutdown after a power reduction and subsequent separation from the grid, continued operation would depend on the ability of the turbine speed control circulty to respond sufficiently to avoid a turbine overspeed and actuation of main generator protection functions.
Dresden Station has not proposed this provision be added to the subject Technical Specification. Dresden Station believes it to.he more prudent to operate at a power level to be determined based on the conditions and configuration at the time of the occurrence. Additionally, a forced power reduction may conflict with the load dispatcher efforts to sustain grid
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a stability, which has the potential to affect the time in which incoming power
=is restored.
Commonwealth Edison Company _ has not proposed changes to the Dresden and Quad Cities TS related to operation of the plants following the loss of both-
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offsite. power lines. Therefore, no action on_the part of the staff is required at this time. However, there is clearly a _ difference in operating-philosophy uetweea the two stations on this issue and one of the approaches is probably better-t!.an the other although it is not-readily apparent.
Commonwealth Edison Company stated this issue is undergoing further evaluation at Quad Cities and will be evaluated within the ongoing TS upgrade propr:3 Since CECO has committed, as part of the upgrade program, to a consistent approach between both sites, except for design differences, the staff expects that these di'ferences will be resolved when the upgraded TS Section 3.9/4.9 is submitted and that adequate justification will be provided.
2.6.Q.uad Cities Backfeed Modification Chanaes The current Quad Cities Technical. Specification 3.9.A.3 provides the requirement for the availability of a second source of offsite auxiliary power _.
during reactor operation.
This source of offsite auxiliary power is specifically described as:
"One oti er 345-kV'line and unit reserve aux transformer capable of carrying auxiliary power to _ an_ essential electrical bus _ of the-unit through the 4160-volt bus tie-shall be available."
- Although the current requirement ensures that two independent sources of offsite auxiliary power are available to provide:the necessary power for loads-which are required to operate to mitigate the consequences-of-postulated-abnormal occurrences and design basis accidents,. it specifically delineates-that the other unit's reserve auxiliary transformer shall be-used as the.
second source of offsite power. -Based upon a loss-of-offsite-power-event at Dresden Station in-1985 and the-recognition of. transformer aging ccncerns,,
CECO initiated an engineering evaluation at Dresden and Quad Cities Stations to. identify modifications and or procedure changesLwhich would be necessary to -
provide a second source of offsite powcr when.the reserve auxiliary transformer (RAT) is unavailable. Based upon:this engineering evaluation, Ceco will= be implementing modifications and procedure changes at both-stations-which will allow the backfeed of power.from the offsite distribution system s through the main power transformer l(MPT) and unit auxiliary transformer (UAT) of a-shutdown unit to an operating unit through the 4160-volt'~ bus tie.
Currently, both Dresden and Quad Cities Station will be implementing the required protective r_elay modifications during the next refuel outage on each un_i t..
However, in order to util ie the backfeed option when the RAT of the shutdown unit is unavailable, Quad Cities TS 3.9.A.3 (ORP-29 and DRP-30) must be: revised-to account for the ability to supply'offsite power through-the-MPT/UAT and 4160-volt bus-tie.
Dresden Station TS 3.9.A.3 requires an offsite
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,. line :apable of carrying power to an essenti&l service bus through 4160-volt bus tie, but d9es not specify that it has to provided through the VAT.
The proposed amendment to Quad Cities TS 3.9.A.3 for Unit 2 (OPR-30) will be necessary following _ implementation of the modification on Unit 1 in October 1992. Subsequent to the completion of the modifications to Unit 1, the Unit 1 RAT (TR-12) will be taken out-of-service for repair, inspection and testing.
The duration of planned work activities for TS-12 is currently 14 days.
This would result in the shutdown of Unit 2 within seven days if the proposed TS amendment is not implemented by that time.
The proposed amendment will delete the current requirement for TS 3.9.A.3 and adopt the wording of Dresden, Unit 2, TS 3.9.A.3 which states:
"One 345 KV line from Unit 3 capable cf carrying auxiliary power to an essential electrical bus of Unit 2 through the 4160 volt bus tie shall be available."
The staff has evaluated the proposed amendment and determined it is acceptable since the change only provides additional flexibility, by allowing the use of either the MPT or the VAT of the shut down unit to supply power through the 4160-volt bus tie to an operating unit during extended RAT outages.
2.7 Administrative Chanaes The proposed amendment also contains administrative changes such as the deletion of redundant requirements, combining, clarifying and rearranging requirements and wording changes to provide consistency between the Dresden and Quad Cities TS.
Since these are editorial in nature the staff has determined they are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of the amendments.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATlQN The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The NRC staff has determined that the amendrrents involve no significant increase in the amounts, and no si". ificant change in the types, of any effluents that mey be released orfsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed fir. ding that the amendments involve no significant hazards consideration, and there has been no public comment on such-finding (57 FR 42770).
Accordingly, the amendments meet the eligibility criteria for categcrical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR
c.
, Sl.22(b), no environmental impact statement or environmental assessment need be prepared la connection with the issuance of the amendments, 5.0
_(D_NCLUSION The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will_ be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
Byron L. Siegel Date: October 19, 1992 i-
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