ML20082R690

Application for Amend to Licenses DPR-53 & DPR-69,revising TS 4.8.1.1.2.d.1 to Allow Removal of Dedicated Class 1E Emergency Power Source from Shutdown Unit for Seven Days

ML20082R690
Person / Time
Site:	Calvert Cliffs
Issue date:	09/05/1991
From:	Creel G BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20082R693	List: ML20082R690 ML20082R696
References
NUDOCS 9109160211
Download: ML20082R690 (9)

Text

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t3ALTIMORE GAS AND ELECTRIC CHARLES CENTER

• P.O. BOX 1475

• BALTIMORE. MARYLAND 21203-1475 I

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September 5.1991 4 i

I U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document ControlDesk

SUBJECT:

Calvert Cliffs : Tuclear Power Plant Unit Nos.1 & L Dcycket Nos. 50-317 & 50-318 Request for Amt.*:. ment to Operating 1.icenses Gentlemen:

The Baltimore Gas and Electric Company (BGRE) hereby mquests an Amendment to its Operating License Nos. DPR-f3 and DPR-69 for Calvert Cliffs Uim Nos. I and 2, respectively, with the submittal of the proposed change to the technical specifications.

DESCRIPTION OF CIIANGE This change will allow the removal of the dedicated Class 1E emergency power source from a shutdown unit for seven days. Currently our technical specifications a'e structured so that No.12 Emergency Diesel Generator (EDG) cannot be removed from service for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> without both nuclear units being shutdown. We plan to remove No.12 EDO from service on

- October 18, 1991, to perform the inspection and ma!ntenance activities require! by Technical Specification 4.8.1.1.2.d.1, Baltimore Oas and Electric Company maintenance policy now recommends that we allot seven days to conduct these activities in a quality manner. To facilitate this and certain other required maintenance und .urveillance tesdng, we will shut down one unit before the current surveillance intervr.1 for No.12 EDG cxpires. The operating unit requires two Class IE emergency power sources to be operable. We will align the operable dedicated dicsci from the shutdown unit to the operating unit during the time that No.12 EDG is out of service. We will also take compensatory measures for the shutdown unit to provide assurance that A.C. electrical power will be available to necessary equipment during this scheduled maintenance.

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Document Control Desk September 5,1991 Page 2 ItACKGROUNI)

We request that this change be approved by October 18,1991. We regret this abbreviated schedule, Surveillance Requirement 4.8.1.1.2.d.1 requires that we perform inspection and maintenance on No.12 EDG by December 6,1991. In early 1991 we made plans to perform this inspection in the fall 1991 Unit 2 outage by aligning the two remaining EDGs to the operating unit, while providing a temporary diesel generator to the shutdown unit. At the time these plans were made, no licensing actions were considered necessary to support it. Specifically, the realignment of the EDGs is described in the Updated Final Safety Analysis Report (UFSAR) Section 8.4.1.2, Table 8-9. Also, the technical specifications in effect at the time allowed the EDO normally dedicated to the

<hutuown unit to be unavailable for an indefinite period of time, provided that certain compensa'ory actions were taken.

Ilowever, Amendments 155 and 135 to Units 1 and 2 Technical SpeciGeations 3.8.1.2 and 3.8.2.2, issued June 27,1991, revised those specifications and adopted CE Standard Technical Specifications wording. The purpose of that license amendment was to revise the action requirements for the containment boundary of a shutdown unit as regards the operability of A.C. power sources. An unforeseen tesult of this new specification is that it would not allow No.12 EDG to be removed from service fr r :nspection for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> without shutting down both nuclear units. Ahhough we applied for this amendment in November 1990, we failed to recognize the irnplications of the Standard Technical Specifications until the change was being implemented and we were in the final stages of planning the - fall 1991 Unit 2 outage. These circumstances were identified on August 22,1991. Following identiGeation of this problem, we developed this license amendment request as expeditiously as possible.

In the past, the inspection and- maintenance of No. 12 EDG required by Technical Specification 4.8.1.1.2.d.1 was performed with one unit shutdown (Mode 5 or 6) and one unit operating (Mode 1,2,3, or 4) :n ACTION 3.8.1.1.a, which allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore an inoperable EDG. Performance of this work in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is no longer practicable due to the increased detail and requirements contained in the maintenance procedure. We determined that the safest approach would be to align both operable EDGs to the operating unit. Even though the shutdown unit has a lower vulnerability to a loss of offsite power, we decided that it was prudent to require an additional offsite power source and to make a temporary diesel generator available to that unit. This provides added assurance that A.C. power would be available to the shutdown unit in case of an event such as that which occurred at Vogtle.

Analyzing the potential maintenance which could be required, we believe that seven days should be allocated to perform the No.12 EDG inspection. This period is consistent with other action statements which will be irwoked upon loss of an operable EDO for the shutdown unit. The most limiting action statement is Technical Specirication 3.7.6.1 (Control Room Emergency Ventilation System).

The Calvert Cliffs Nuclear Power Plant emergency A.C. electrical power configuration consists of three EDGs. No.11 EDG is normally aligned to Unit 1, N7. 21 EDG is normally aligned to Unit 2, 4 and No.12 EDG, which is a common or " swing" diesel, and may be aligned to either unit. The design also allows for the normally dedicated diesel to be aligned to the other unit; i.e., No.11 EDG aligned to Unit 2 or No. 21 EDG aligned to Unit 1. This arrangement allows the swing diesel (No.12 EDG)

• to be removed from service while still meeting the operating requirements of Technical Specification 3.8.1.1 (two EDGs operable while in Modes 1, 2, and 3) for one unit. This configuration is described in Table 8-9 of Section 8.4.1.2 of the UFSAR.

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Document Control Desk September 5,1991 Page 3 The primary circuit for offsite A.C. electrical power is through two independent 500 kV transmission lines connected to the BG&E grid at the Waugh Chapel substation. These lines provide power to the ' units during normal operation as well as during startup and shutdown. The system is also designed with the capability for a single 500 kV line to power both units simultaneously. This diversity ensures that the lon of a single 500 kV line will not result in a loss of offsite power, in the event that both 500 kV power lines are lost, there is a 69 kV feeder from Southern hiaryland Electric Cooperative (Shf ECO) which i, capable of handling all of the safe shutdown loads at the site (it has a capacity equivalent to two EDGs) and is a fully qualified power source as described in UFSAR Section 8.2A. The Sh1ECO feeder is not connected directly to the BG&E grid and approaches the plant from a separate right-of.way. ShiECO obtains power from Potomac Electric )

Power Company. Therefore, the Sh1ECO feeder's only connection with the BG&E grid is through I the Pennsylvania /New Jersey /htaryland power pool. This ensures that any disturbances on the BG&E grid will have little, if any, effect on the ShiECO feeder.

The D.C, electrical power system (including the batteries, the battery chargers, and the inverters) is common to both units. A single EDG is capable of providing battery charging to both units.

In response to the Station Blackout rule (10 CFR 50.63), BG&E has committed to install two additional EDGs which are scheduled to be installed by February,1995. 'these additional EDGs will allow any one EDG to be removed from service while still providing two EDGs to support each unit.

Therefore, this change to the technical specifications will only be needed until the new EDGs are operational.

REOUESTED CilANGE

- Change Specifications 3.8.1.2. "ELt:.CTRICAL POWER SYSTEhtS - SilUTDOWN", and 3.8.2.2, "A.C. DISTRIBUTION - SilUTDOWN", of the Unit I and Unit 2 technical specifications as shown on the marked.up pages attached to this transmittal. This change constitutes an exception from the present requirement for a_n operable EDG on the shutdown unit, and will allow the dedicated EDG from the shutdown unit to be aligned to the operating unit. Compensatory measures which will be

- taken for the shutdown unit are:

-- Either two 500 kV offsite power circuits or one 500 kV offsite power circuit and the 69 kV Sh!ECO offsite power circuit shall be available.

- Planned maintenance on the 500 kV transmission lines from the Waugh Chapel substation through the Calvert Cliffs switchyard will be piohibited,

- Core alterations, positive reactivity changes, movement of irradiated fuel and movement of heavy loads over irradiated fuel will be suspended and containment penetration closure will be established, and 5

- A temporary diesel generator capable of carrying the shutdown unit's A.C. electrical loads will be available, o

If these conditions are not met, then four hours are allotted to restore compliance. If compliance is not restored within the next four hours, then an operable EDO must be aligned to the shutdown unit within the next four hours. This will place the operating unit in ACTION statement 3.8.1.1.b (lack of

Document Control Desk September 5,1991

- Page 4

-two EDGs) which allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore two operable EDGs or be in hot standby in the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown in the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Because these inspection and maintenance activities on No.12 EDG are required every 18 months, we anticipate that EDG 12 will be removed from senice for required inspection and maintenance rit least three times prior to the installation of the two additional EDGs. This proposed change, if approved, will be removed when the technical specifications are revised to rencet the addition of the new EDGs.

Additions to the Technical Specifications Bases to reDect this change have also been proposed.

- SAFirIT ANAINSES! JUSTIFICATION The event of concern is a loss of offsite power to a shutdown unit (hlodes 5 or 6). The probability of a loss of offsite power during the seven days that No.12 EDO is out of senice for the required inspection is very low because of the reliability ar.d redundant nature of the offsite power sources.

Either of the two 500 kV transmission lines or the 69 kV Sh1ECO line can provide power to the safe shutdown loads of both units. We will prohibit planned maintenance en the 500 kV lines from the Waugh Chapel Substation through the Calvert Cliffs switchyard during the time that No.12 EDG is

- out of senice. The 69 kV feeder line is an independent power circuit and we will verify its availability once per shift.

The potential for a k>ss of offsite power due to severe weather has also been considered. The 500 kV transmission lines and towers are designed to withstand winds of 100 and 160 mph, respectively.

Winds of this velocity could be from a hurricane or a tornado. The incidence of hurricanes of 100 mph magnitude in the Calvert Cliffs area is very low (only one in recorded history). Tornadoes can be spawned at any time, given the right meteorological conditions. Tornadoes with wind velocities in excess of 100 mph in the Calvert Cliffs area are also very rare. Regardless of the incidence of tornadoes, the offsite power supply could withstand a tornado with winds in exess of 100 mph. This is because the 500 kV lines and the Sh!ECO feeder occupy different rights of way and it is extremely unlikely that a single tornado would strike both. At the site, the 500 kV lines are overhead while the SMECO feeder is underground. A tornado at the site may damage the 500 kV lines, but would not affect the SMECO feeder. Should the she or the offsite power circuit's right-of-way be threatened by severe ' weather, Emergency Response P%n -Implementing Procedure (ERPIP)3.0 requires actions which lead to placing both units in Hot Standby depending on the severity of the weather. A copy of the weather e mdition/ action table from ERPIP 3.0 is included as Attachment 3.

In the very unlikely event that there is a total loss of offsite powerithe temporary diesel generator will be used to power the electricalloads of the shutdown unit. A 50.59 Safety Evaluation has been

- performed to confirm that the connection of the temporary diesel generator to the emergency busses will not impair existing safety related equipment.

The temporary diesel generator will have the electrical capacity to power all shutdown loads for a unit in Mode 5 or 6. The temporary diesel generator requires no outside power source to start (black start). - The equipment arrangement for the upcoming Unit 2 outage is shown in Attachment 4. A portable foam fire suppression unit will be located at the temporary diesel generator and Calvert Cliffs personnel will be trained in its use. Adequate measures will be provided to cusure that the temporary diesel generator and fuel tank are not inadvertently damaged. The temporary diesel generator will be connected to the emergency bus through an existing safety-related circuit breaker.

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Document Control Desk September 5,1991 Page 5 This breaker forms the isolation point between safety and non. safety related systems. Personnel trained on the alignment and starting of the temporary diesel generator will be on each shift. Fuel

will be supplied from a 7000 gallon mobile tanker and the fuel will be sampled for purity in accordance with approved plant procedures. This amount of fuel will supply the temporary diesel generator for approximately 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br />. We will review the supplier's maintenance records to ensure that the maintenance on the temporary diesel generator has been adequately performed and is current. Prior to removing the dedicated EDGs from the shutdown unit, the temporary diesel i generator will be load tested to verify

+ The temporary diesel generator starts and operates with a generator voltage of 4160 +/- 420 volts and a frequency of 60 +/- 1.2 Ilz,

+ The temporary generator is synchronized, loaded to greater 1700 kw and operates for greater than 60 minutes, and i

+ The temporaq diesel generator is aligned to provide standby power to the associated eracrgency busses. 1 During the seven-day maintenance period, the temporary dicsci generator will be test-started at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and a generator voltage of 4160 +/- 420 volts and a frequency of 60 +/- 1.2 Ilz will be verified. (Instrumentation installed on the temporary diesel generator may be used during the performance of these tests.) With these provisions, we are confident that the temporary diesel generator will be available to supply shutdown loads in the unlikely event that offsite power is lost.

Two accidents are evaluated for a unit in Mode 5 and 6. They are a fuel handling accident and a baron dilution event. The fuel handling acc. dent is precluded because no core alterations or other movement of irradiated fuel will take place. Containment closure is provided as a precaution. The baron dilution event is rendered unlikely by requiring that positive reactivity changes be suspended.

However, the temporan diesel generator can power the equipment required to respond to the baron dilution event if needed.

During the seven. day period when the dedicated EDO is transferred to the operating unit (i.e., when we are in Action Statement 3.8.1.2.b or 3.8.2.2.b) we will not conduct any operations involving reduced RCS inventory.

The requested change will allow a more thorough and orderly inspection of No.12 EDG to be conducted than can be accommodated under the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement that now applies. This will enhance the lor;-term reliability of the EDG. This enhancement outweighs any temporary reduction in the reliability of the shutdown units' power sources resulting from the short-term unavailability of the normally dedicated Class IE EDG. The additional provision of the temporary diesel generator for the shutdown unit will provide substantial further compensation. The net effect on plant safety is positive, In the short term, i.e., during the proposed seven-day allowed outage time for No.12 EDG inspection, the safety of the operating unit is enhanced by allowing two Class lE EDGs to be continuously available to respond to any design basis events. For the shutdown unit, an adequate level of safety is maint .. ied by a combination of compensatory measures that minimize the likelihood of accidents, yet proviac a source of emergency onsite power should any of these events occur. - Furthermore, the proposed action statements provide specific time limitations for the restoration of A.C. electrical power sources that do not exist in the current technical specifications for A.C. electrical power sources on a shutdown unit. Inahility to satisfy these action statements within a specified time would result in shutdown of the operating unit, thus placing the plant in the safest possible condition.

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Document Control Desk -

September 5,1991 Page 6 in summary, the proposed combination of additional redundancy in offsite A.C. power sources, restrictions on onsite activities that could lead to accidents, and the installation of a temporary diesel generator, provide reasoaable usurance that the health and safety of the public will be protected.

DETEliMINATION OF SIGNIFICANT ll AZAlti)S The proposed changes to Technical Specifications 3.8.1.2 and 3.8.2.2 have been evaluated against the standards in 10 CFR 50.92 and have been determined to not involve a significant hazards consideration,in that operation of the facility in accordance with the proposed amendment:

1. IVouki not involve a significant increase in the probability or consequences of an accident previously evaluated.

This change was evaluated to determine its impact on the probability or consequences of a loss of offsite power event, a boron dilution event, and a fuel handling incident. The boron dilution event and the fuel handling incident are the only two accidents that are explicitly analyzed in the Updated Final Safety Analysis Report (UFSAR) for a shutdown unit.

There is a very low probability of occurrence of a loss of offsite power during the seven day period that No.12 Emergency Diesel Generator (EDG) would be cut of service fcr inspectiovi and maintenance. This configuration will only be required until two additional Class IE EDGs will be installed (about February 1995) as part of BGRE's implementation of the Station Blackout Rule (10 CFR 50.63). These new EDGs would provide suf0cient Dexibility for scheduling and performing maintenance such that this relief from technical specification requirements will no longer be needed.

To ensure a low probability of a loss of offsite power, BG&E has reviewed potential precursors such as weather events and onsite work activities. The Calvert Cliffs offsite power supply is designed to be diverse and redundant, and is therefore inherently capable of withstanding severe weather events. In addition, BG&E's Emergency Response Plan already requires that certain actions be taken, up to and including shutdown of both units, on the approach of a severe storm.

As regards werk-related events, the probability of a loss of offsite power is maintained low by prohibiting planned maintenance on the two 500 kV transmission lines and in the switchyard.

Availability of the independent offsite power source, the 69 kV Southern Maryland Electric Cooperative (SMECO) feeder, will be verified once per shift. This requircinent to maintain two available qualified offsite power sources compares favorably with the requirements of the current technical specifications to maintain only one offsite source to the shutdown unit.

A temporary diesel generator will also be installed to provide a backup onsite source of power capable of supporting necessary safety-related loads.

Finally, potential accident precursors such as core alterations, positive reactivity insertions, movement of irradiated fuel and movement of heavy loads over irradiated fuel, will be prohibited while No.12 EDO is out of service. Therefore, the probability of a boron dilution event or fuel handling incident is decreased during the operations allowed by this change.

The requirement to m.aintain containment penetration closure while No.12 EDG is out of sersice ensures that the consequences of an accident would not be significantly ine: cased.

Document Control Desk September 5,1991 Page 7 Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. li'ould not create the possibility of a new or different type of accident [nnn any accident previously evaluated.

A temporary dicsci generator is being installed onto the 4 kV bus of a shutdown (Mode 5 or 6) unit while the dedicated EDG for this unit is transferred for up to seven days to the operating unit. This configuration allows the performance of inspection and maintenance required by Technical Specification 4.8.1.1.2.d.1 for No.12 EDG This change has been evaluated and it has been determined that this installation does not impair any existing safety-related equipmer t needed to maintain the unit in a safe shutdown condition. Differences in the operation of the temporary diesel generator and the permanent EDGs include manual starting of the temporary die ci generator and manual loading of the 4 kV bus. These operations are lot significantly different from typical operator activities.

Therefore, the proposed change does not create the possibility of a new or different type of accident from any accident previously evaluated.

3. Ii'ould not involve a significant reduction in a margin of safety.

The operability of the minimum specified A.C and D.C. electrical power sources and associated distribution systems during Modes 5 and 6 ensure that; 1) the unit can be maintained in Mode 5 or 6 for extended time periods and,2) sufficient instrumentation and control capability is available for monitoring and maintaining the unit status. The proposed change does not affect the D.C. power sources or the A.C and D.C distribution systems. It affects only the A.C power sources in that we are removing the emergency A.C power source from the shutdown unit for seven days. This change will have no impact on the offsite power sources. Compensatory measures will be taken for the loss of the emergency power source. They are:

o requiring that two offsite power sources are available,

+ core alterations, positive reactivity changes, movement of irradiated fuel, and movement of heavy loads over irradiated fuel, will be suspended, and

+ containment penetration closure will be established.

These compensatory measures reduce the potential for a loss of offsite power, a fuel handling accident, and a boron dilution event during the seven days that the emergency power source is not available to the shutdown unit. Additionally, we are providing a temporary diesel generator capsble of supplying the loads necessary to maintain the unit in a safe condition.

These measures, along with the irifrequent need to enter this condition, ensure that the margin of safety is not significantly reduced.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Document Control Desk -

September 5,1991 ,

Page 8 i

i SCllEDUI.E .

t We have scheduled maintenance on No.12 EDO during the fall 1991 Unit 2 maintenance outage scheduled to commence in October, No.12 EDG is piesently scheduled to be removed from sersice i on October 18; therefore, this change is requested to be approved by that date, to support the overall r outage schedule.

i SAFiflY COMMITTEE It13'IEW f t

These proposed changes to the technical specifications and our determination of significant hazards  ;

have been reviewed by our Plant Operations and Safety Review Committee and Off-Site Safety i Review Committee, and they have concluded that implementation of these changes will not result in l an undue risk to the health and safety of the public. 3 Very truly yours, STATE OF MARYLAND .

y 4 L L / A E df  !

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I hereby certify that on the 8d day of gMdu,19M before me, the subscriber,  ;

a Notary Public of the State of Maryland itf and for EM Omm2L/ ,

personally appeared George C. Creel, being duly sworn, and states that he is Vice Presid6nt of the  ;

Baltimore Gas and Electric Company, a corporation of the State of Maryland; that he provides the i foregoing response for the purposes therein set forth; that the statements made are true and correct to the best of hi:. knowledge, information, and belief; and that he was authorized to provide the  ;

response on behalf of said Corporation.

WITNESS my Hand and Notarial Scal: I,4

/

~/ [ Notary Pulih Marguerito F. Strobel  :

My Commission Expires  :

January 1,1995 l, My Commission Expires: l; Date GCC/BDM/bdm/bjd/dlm Attachments A

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y,y, -- y m,vy

Document Control Desk

. September 5,1991 Page_9

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. cc: D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC.

D. G. Mcdonald, Jr., NRC T. T. Martin, NRC L. E. Nicholson, NRC R. I. McLean, DNR J. II. Walter, PSC

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