ML20115E799
| ML20115E799 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/10/1996 |
| From: | Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20115E801 | List: |
| References | |
| TXX-96405, NUDOCS 9607160231 | |
| Download: ML20115E799 (17) | |
Text
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P=== Log # TXX-96405 2M File # 916 (3/4.7)
- - Z 10010 C
C-Ref. # 10CFR50.90
. 10CFR50.36 1UELECTRIC ,
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- c. tance Terry July 10,1996 Group % e Prendent U. S. Nuclear Regulatory Commission Attn: Document Control Desk i Washington, DC 20555 .
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) l DOCKET NOS. 50 445 AND 50 446 l SUBMITTAL OF LICENSE AMENDMENT REQUEST 96 004 UNINTERRUPTIBLE POWER SUPPLIES (UPS) HVAC SYSTEM i ADDITION OF FAN COIL UNITS TO TECHNICAL SPECIFICATIONS l l
Gentlemen:
Pursuant to 10CFR50.90, TU Electric hereby requests an amendment to the CPSES Unit 1 Operating License (NPF-87) and CPSES Unit 2 Operating License (NPF 89) by incorporating the attached changes into the CPSES Units 1 and 2 Technical Specifications. These changes apply equally to CPSES Units 1 and 2.
The proposed change to the Technical Specification 3/4.7.11 revises Limiting Condition for Operation (LCO). ACTIONS and Surveillance Requirements to take credit for the addition of train oriented Fan Coil l Units for each UPS & Distribution Room. The addition of UPS Fan Coil Units will be redundant to the existing Air Conditioning (A/C) Units and provide more flexibility in the operation of the UPS HVAC System. The proposed change will reduce the likelihood of plant transients as a result of UPS HVAC System failures and reduce the possibility of the forced shutdown of both CPSES Units at the same time.
Attachment 1 is the required affidavit. Attachment 2 provides a detailed description of the proposed changes, a safety analysis of the proposed changes and TU Electric's determination that the proposed changes do not involve a significant hazard consideration. Attachment 3 provides the affected technical specification pages (NUREG 1468) marked up to reflect !
the proposed changes.
I 9607160231 960710 PDR ADOCK 05000445 P
i PDR T-s \
Energy Plaa IMJi Bryan Street Dallas, Texas 75201 1461 x 5 I
i TXX 96405 Page 2 of 2 In parallel with the review and approval of this License Amendment request, i TV Electric is processing the design modifications to add Fan Coil Units to CPSES Unit 1 and 2. TV Electric requests that the License Amendment be approved on or before May 1. 1997, with implementation of the Technical Specification changes to occur within 30 days thereafter. In case of failure on both existing Air conditioning Trains and no cooling is available to UPS Rooms, an earlier approval of this License Amendment Request will be requested to avoid shutdown of both units.
In accordance with 10CFR50.91(b). TU Electric is providing the State of Texas with a copy of this proposed statement.
Should you have any questions, please contact Mr. Manu C. Patel at (214) 812 8298.
Sincerely, o
C. L. Terry By: M -
Roger U. Walker Regulatory Affairs Manager MCP/grp Attachments: 1. Affidavit ;
- 2. Description and Assessment '
- 3. Affected Technical Specification pages (NUREG 1468) as !
revised by all approved license amendments c- Mr. L. J. Callan, Region IV i Mr. P. M. Ray, NRR !
Ms. L. J. Smith, Region IV Resident Inspectors, CPSES Mr. Arthur C. Tate Bureau of Radiation Control j Texas Department of Public Health 1100 West 49th Street Austin, Texas 78704 I
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. Attachment 1 to TXX 96405 Page 1 of 1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION l l
In the Matter of )
) Docket Nos. 50 445 Texas Utilities Electric Company ) 50 446
) License Nos. NPF-87 (Comanche Peak Steam Electric ) NPF 89 Station, Units 1 & 2) )
AFFIDAVIT Roger D. Walker being duly sworn, hereby deposes and says that he is l Regulatory Affairs Manager of TV Electric, that he is duly authorized to l sign and file with the Nuclear Regulatory Commission this License Amendment l Request 96-004: that he is familiar with the content thereof; aied that the matters set forth therein are true and correct to the best of his i knowledge, information and belief. !
M Roger E. Walker i
Regulatory Affairs Manager STATE OF TEX.% )
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COUNTY OF DALLAS )
Subscribed and sworn to before me, a Notary Public, on this ICb day of Iulu . 1996.
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_m -- -------- [1 p cL 1 Gayle R. Peck ,
- . e i Notary Public. State of Texas ,
J My Comm.Expres 01/06/98 l . ....-
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ATTACHMENT 2 TO TXX-96405 DESCRIPTION AND ASSESSMENT l
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. Attachment 2 to TXX 96405 Page 1 of 13 DESCRIPTION AND ASSESSMENT L BACKGROUND The Uninterruptible Power Supplies (UPS) Heating Ventilating and Air Conditioning (HVAC) System is a shared common support system for the UPS &
Distribution Rooms for Units 1 and 2 composed of two electrically independent, 100% capacity, trains of HVAC including Air Conditioners (A/C) and booster fans. The cooled air is recirculated from either "A/C Train" through all four Class 1E UPS and Distribution Rooms via shared ductwork. The air conditioners are supported by Component Cooling Water from either Unit 1 or 2 by manual valve line up. l i
A design modification to the UPS HVAC System will add a 100% capacity UPS Room Fan Coil Unit (FCU) to each of the four UPS & Distribution Rooms.
These rooms are unit and train specific: Unit 1 Train A. Unit 1 Train B.
Unit 2 Train A, and Unit 2 Train B. These UPS Room Fan Coil Units will replace the UPS A/C Trains as the primary source of UPS cooling. Each FCU will be independently powered from the Unit 1 or Unit 2 Class 1E Safeguards buses by the same train as the UPS in the room it supports.
FCU cooling water will be provided from the respective unit and train of Safety Chilled Wa+er.
The new UPS Room Fan Coil Units will increase the reliability of the UPS HVAC System and reduce the possibility of a forced shutdown of both CPSES Units as a result of UPS HVAC System failure. The design modifications to install the new UPS Room Fan Coil Units were reviewed per 10 CFR 50.59 and did not create an unreviewed safety question or require a change to the Technical Specifications. CPSES will remain compliant with the existing Technical Specifications with these modifications installed and operating.
To optimize the benefits and control of this modified system. TU Electric is proposing the following revision to CPSES Technical Specification 3/4.7.11 regarding the operability of the cooling for the UPS &
Distribution Rooms.
Technical Specification 3/4.7.11, the specification for the UPS HVAC System, is a plant specific specification and is not covered by Standard Technical Specifications. However, its basis is similar to the " Control Room Air Conditioning System" Technical Specifications of NUREG-1468 (Reference 1), the CPSES Units 1 and 2 Technical Specifications, and Limiting Conditions of Operation (LCO) 3.7.11, Control Room Emergency Air Temperature Control System, of NUREG 1431 (Reference 2).
IL DESCRIPTION OF TECHNICAL SPECIFICATION CHANGE REQUEST The proposed revision to Technical Specification 3/4.7.11:
(1) redefines the existing LC0 to be based on each UPS &
Distribution Room with an OPERABLE same Train UPS A/C Train instead of requiring two OPERABLE A/C Trains for all four rooms,
Attpchment 2 to TXX 96405 Page 2 of 13 (2) takes credit for new UPS Room Fan Coil Units to satisfy the LCO, (3) changes this specification from a shared to a unit specific specification, (4) modifies the existing action statement concerning the loss of one train of redundant cooling to conform to the new support sciv.ne and changes the Allowed Outage Time from 7 days to 30 days, (5) adds two new action statements (one to address the condition when a UPS & Distribution Room's FCU and both UPS A/C Trains are inoperable but an A/C Train ventilation air recirculation is available and the other to address the condition when there is no OPERABLE cooling or ventilation air recirculation available), i (6) adds a surveillance requirement for these UPS Room Fan Coil l Units, !
(7) revises the UPS A/C Train 18 aonth surveillances to only apply to " required" trains and to incorporate the standard wording of i
NUREG 1431 for testing the train start on an actuation signal, and (8) revises the 31 day surveillance to apply only to the " required" )
trains and to delete the requirement to start each train every 31 1 days. I 1 Each of these changes is discussed briefly below:
- (1) The revised LC0 is based on proper support for each UPS &
Distribution Room. The UPS A/C Trains needed to satisfy the LCO, for a given area, are changed from two inde)endent Trains, to an 4
OPERABLE Train which is the same Train as t1e UPS in that area.
(2) The UPS Room Fan Coil Units are added to the Limiting Condition for Operation (LCO) as an additional method of providing sufficient cooling for the acsociated uninterruptible power supplies.
l (3) The reference to Units 1 and 2 is deleted from the ACTION statement. This phrase indicated that the action was applicable to 4
both units because the UPS A/C Trains are common to both units. The UPS & Distribution Rooms are to be provided with independent UPS Room Fan Coil Units and no longer will it be appropriate for both units to enter an ACTION statement for all events. The new UPS Room Fan Coil Unit function is to support the associated Train of UPS equipment for the Unit in which it is located. The UPS Room Fan Coil Units are not shared between Units 1 and 2. Therefore, this specification is revised to be applicable to each unit individually, and are not applicable to both units.
(4) The ACTION requirement is rewritten to reflect the revised operability portion of the LC0 and an increase in the Allowed Outage Time (A0T) based on the similarity between this specification and
l Attachment 2 to TXX 96405 Page 3 of 13 the Technical Specifications for the Control Room HVAC System. The shutdown requirements remain unchanged.
(5) The first new action 1s based on the ability of the system's ventilation fans recirculating air cooled by OPERABLE Fan Coil Units in other UPS rooms to naintain area temperature when a UPS and Distribution room's FCU and both A/C Trains are inoperable. The second new action statement requires shutdown in the event the other two actions are not satisfied. ;
1 (6) A new SURVEILLANCE requirement was added for the UPS Room Fan l Coil Units to verify their operability monthly when they are ,
required to be operable. l (7) The 18 month surveillance requirements for the UPS A/C Trains were revised to apply to required trains only. The start based on actuation signal now allows either actual or test signals and does not specifically identify the actuation signals.
(8) The monthly verification of OPERABILITY was changed to apply to required trains only and to remove the requirement that the train be started each month, as long as it operates for at least one hour during the month.
In summary, the proposed revision makes the specification unit specific in order to take credit for new UPS Room Fan Coil Units and same train HVAC while adding ACTION statements to address loss of cooling with ventilation still available.
ILL ANALYSIS BAEGROUND The Class 1E,118 VAC single phase, 60 Hz, grounded uninterruptible power is supplied to critical instrumentation and control circuits. In each unit there are four Class 1E static uninterruptible power supplies (UPS) for Balance of Plant (B0P) instrumentation and control systems, and four uninterruptible power supplies for the reactor protection system (RPS).
Each B0P uninterruptible power supply consists of an inverter [ including an AC input rectifier, static (automatic) switch, and bypass (manual) switch) and a bypass transformer. Each RPS uninterruptible power supply consists of an inverter which includes AC and DC source breakers, instrumentation and an output breaker. The primary locations for these UPS and much of their associated power distribution equipment are the "UPS
& Distribution Rooms." There are two UPS & Distribution Rooms in each CPSES Unit, one for each power supply train.
The OPERABILITY of the equipment in the UPS & Distribution Rooms is adequately addressed by Technical Specification 3.7.10. " Area Temperature Monitoring," with respect to room temperature or the adequacy of the cooling system, except for the RPS uninterruptible power supplies.
Att.achment 2 to TXX 96405 Page 4 of 13 Because of the critical function of these devices and the rate at which they can overheat without any cooling or ventilation, a separate Technical Specification (3/4.7.11) is provided for the UPS HVAC System which supports these power supplies.
The primary function of the UPS HVAC System is to provide cooling for Class 1E electrical equipment in the UPS & Distribution Pooms. Trains A &
B, Units 1 and 2, (Electrical & Control Building (ECB) elevation 792' 0")
and the mechanical equipment room (ECB elevation 778' 0"). The primary and limiting safety related components in these rooms are the RPS uninterruptible power supplies.
A design modification will add a 100% capacity UPS Room Fan Coil Unit to each of the four. UPS & Distribution Rooms. These UPS Room Fan Coil Units
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will function as the primary source of UPS cooling and will be independently powered from the Unit 1 or Unit 2 Class 1E !afeguards buses.
Cooling wcter will be provided from the respective unit and train of Safety Chilled Water.
The existing UPS HVAC System consists of two 100 percent-capacity air conditioning units (UPS A/C Trains), each of which is powered by common electrical distribution equipment. Each unit is supplied with condenser cooling water from the same train of either the Unit 1 or Unit 2 component cooling water (CCW). During normal operation, only one condenser cooling water path is open (i.e., the units are not cross tied via CCW). During a Station Blackout (SB0), electrical power is assumed to be available to the UPS A/C Trains from the non SB0 unit's EDG: however, the condenser cooling water to the operating UPS A/C Train cooler may be lost. However, fans for the UPS A/C Train will continuously circulate air throughout the UPS &
Distribution Rooms. Using the methodology described in NUMARC 87 00 (Reference 3), the cooling provided by a Fan Coil Unit in the non SB0 unit will aise provide cooling to all four UPS & Distribution Rooms for the SB0 duratior.
The control circuit design of the new UPS Room Fan Coil Units will not include an " auto" start or " standby" feature. The existing UPS A/C frains will be normally maintained in standby. Each new UPS Room Fan Coil Unit will be controlled from a local control panel integral to the unit. The control panel will contain a maintained two position hand switch (on/off).
Each unit will be directly wired to its associated safeguards bus. Upon a Blackout signal ("B0S") or a Safety Injection ("S") signal the bus is energized. The units will automatically restart upon re energizing of the associated safeguards bus. The additional load on the emergency diesel generators has been evaluated and is acceptable. The existing UPS A/C Trains, which auto start upon high temperature in any of the four rooms, will function as 100% redundant and diverse backup cooling to the UPS Room Fan Coil Units.
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. .Att.achment 2 to TXX 96405 Page 5 of 13 NORMAL AND ACCIDENT SUPPORT WITH PROPOSED REVISION TO TECHNICAL SPECIFICATION The existing LC0 requires that both UPS A/C Trains be OPERABLE. The proposed change regarding the LC0 requires that each UPS & Distribution 4 Room be supported by either an OPERABLE UPS Room Fan Coil Unit or an OPERABLE UPS A/C Train which is the same train as the UPS in that' room.
Each safety related UPS Room Fan Coil Unit is the same train and same CPSES Unit as the equipment in the UPS & Distribution Room that it supports and the UPS Fan Coil Units will continue to operate or automatically restart following an accident. Therefore, the'UPS Room Fan Coil Unit will' provide proper support for the UPS & Distribution Rooms for
( normal operation of each CPSES Unit and will provide the proper support l for design basis accidents.
l The proposed specification adds a surveillance that required UPS Room Fan Coil Units be operated for at least one hour each month. This will assure that those UPS HVAC Units which are relied upon to satisfy the LC0 are capable of operating as required to support the equipment in their respective supported areas. 1 By similar logic, "same train" cooling by a UPS A/C Train provides proper support for each UPS & Distribution Room for both normal and design basis accident conditions. Prior to the installation of the UPS Room Fan Coil l Units, there was no value in crediting "same" . Train UPS A/C cooling i because both UPS A/C trains cooled all four UPS & Distribution Rooms. If '
one train was inoperable, at least two rooms (one in each unit), were left without same train support. With the addition of the UPS Room Fan Coil Units, each room can be supported individually and if one UPS A/C Train is inoperable, each UPS & Distribution Room may still have OPERABLE support.
Thus, it is now appropriate to evaluate operability based on each UPS &
Distribution Room and require same train support if the UPS A/C Trains are the back up support relied upon.
Because the UPS A/C Trains support both CPSES Units 1 and 2 and because the existing Technical Specification focuses on both A/C Trains being OPERABLE, the existing specification is a common specification which applies to both units simultaneously. Because the proposed revised specification focuses on each UPS & Distribution Room and it is possible to support each room independent of the others, it is no longer appropriate to consider both CPSES Units simultaneously. Thus it is
, proper for the proposed specification to apply to each CPSES Unit l
( separately.
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! The proposed changes modify the existing surveillance requirements for the i UPS A/C Trains. The scope of the surveillances is clarified to only apply '
i to the " required" UPS A/C Train. The change is consistent with the l proposed Technical Specification LC0 requirements in which a UPS A/C Train j may no' longer be required to be OPERABLE. It is appropriate to perform
- the surveillance for a UPS A/C Train if that train is being used to i
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Attachment 2 to TXX 96405
! Page 6 of 13 f satisfy the LCO, but it is not necessary to perform the testing on
- equipment which is not required to be OPERABLE. Another proposed change deletes the requirement to " start" an A/C Train to perform the 31 day
- surveillance. The existing words, " starting the non operating UPS A/C train," no longer make sense since both trains may not be in operation.
Operating a train for one hour each month adequately demonstrates its
- expected operability when required. Deleting the " start" requirement allows the operator to simply verify the unit (s) is operating if it is
! already running. The unit does not have to be shut down and then re-i started. Such unnecessary cycling of the equipment may in fact cause l unnecessary wear and tear and reduce its reliability.
! The 18 month surveillance was also changed to combine the Safety Injection r
signal with the Blackout test signal and calling them both "... actual or
- simulated actuation signal." This is consistent with the NUREG-1431, i " Standard Technical Specifications Westinghouse Plants."
l The APPLICABILITY portion of the TECHNICAL SPECIFICATION remains unchanged
- (applicable in MODES 1, 2, 3 and 4) and therefore does not impact this assessment. l 1
l The ACTION statement is changed as discussed below. The first change is to remove the reference to " Units 1 and 2". The new UPS Room Fan Coil i Units function to support the associated Train of UPS equipment for the !
Unit in which it is located. The UPS Room Fan Coil Units are not shared between Units 1 and 2. Therefore, as discussed above, the proposed Technical Specification is applicable to each unit, not both simultaneously.
The other change consists of having three separate ACTION statements l instead of one. The first ACTION statement in the proposed changed technical specification is similar to the existing ACTION statement in that it covers the situation where rooms are supported only by equipment which is not the same train as the equipment in that room (in this case a j
UPS A/C Train which is not the same train as the equipment in the room of -
concern.)
The shutdown requirements are not char.ged by the proposed changes but the Allowed Outage Time (A0T) is changed from 7 days to 30 days. The seven days in the existing specification is consistent with the standard Technical Specification which existed and was used to draft the original CPSES Technical Specifications for the Control Room HVAC System which was similar in design and function. However, since the improved Standard Technical Specifications have been approved, when comparing a similar situation (e.g. , Specification 3/4.7.11. " Control Room Emergency Air Temperature Control System" in NUREG 1431), the A0T is 30 days. The 30 day A0T for this Technical Specification change is reasonable based on the consideration that the remaining UPS HVAC Train is capable of providing the required cooling and that' alternate means can be made available (see the station blackout discussion below. the multiple cooling methods available, and the potential to circulate air by using the UPS A/C Train ventilation fans).
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Attachment 2 to TXX-96405 Pag'e 7 of 13 The second ACTION statement credits the UPS A/C Train supply and return fans and cooling provided by 0PERABLE FCUs as long as the temperature in the UPS & Distribution Rooms remains within the limits specified in Technical Specification 3/4.7.10. Immediate temperature concerns result from the local build up of heat. By circulating the air, local temperature rises are reduced. As long as the temperatures are maintained ;
below the values in Specification 3/4.7.10 for these areas, the equipment I in the areas will remain operable. The A0T is limited to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. l however, based on the risk from an event occurring requiring the inoperable UPS AC Train, and the remaining UPS Room FCUs and UPS AC Train fans providing the required protection.
The third ACTION statement covers the situation where there is no OPERABLE cooling or ventilation at all. The ACTION is to direct the operator to restore the required support within one (1) hour or start shutting down the affected Unit. Such quick response is appropriate because local heating can begin to challenge the OPERABILITY of equipment after cooling and ventilation are lost.
The changes in the BASES are merely descriptions which have been updated l to match the proposed changes to the specification itself and have no I impact o7 the control or operation of the system.
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Overall, the revised specification takes advantage of the new UPS Room Fan Coil Units and provides support which is superior to the existing specification in which only the UPS A/C Trains are credited.
Station Blackout 1
The current SB0 coping study assumes that one Emergency Diesel Generator l (EDG) in the Non-Blacked Out unit operates during a station blackout.
This could cause a total loss of UPS A/C cooling to the UPS & Distribution Rooms since the EDG may not be of the same Unit as the CCW train lined up to supply cooling water for UPS air conditioning. The study does, however, take credit for the air movement provided by the UPS A/C Train ventilation fans. With the addition of normally operating FCUs. at least one UPS Room Fan Coil Unit (over 82,000 BTU /hr capacity) will be operating to provide additional cooling. In the current study, the operability of the UPS A/C Train ventilation fans is, in part, assured by the LC0 requirement that they be OPERABLE and the Allowed Outage Tir.ies specified in the action statements. In the proposed TS change, the LC0 requires either the UPS A/C Trains or the UPS Room Fan Coil Units to be operable and the action statements and surveillances apply only to the required equipment; however, a high degree of availability for the UPS A/C Train ventilation fans is assured both by the revised TS and the associated CPSES procedures which closely monitor the status of TS related equipment and set a high priority on any preventive or corrective maintenance associated with such equipment. In summary, the ability to cope with SB0 is enhanced.
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Att,achment 2 to TXX 96405-Page 8 of 13 Fire Safe Shutdown Analysis (FSSA) / Fire Protection The design of the new UPS Room Fan Coil Units incorporates existing
! licensing commitments of the CPSES fire protection program. Fire Safe
! Shutdown requirements have been identified and incorporated into the i system design, consistent with the fire hazards analysis, fire safe shutdown analysis, and appropriate Design Basis Documents, to ensure adequate train separation and protection. The protection provided is
- adequate to operate the new units in a " stand alone" mode, without reliance upon the existing HVAC System (which is also protected).
Combustible loading for the new units is negligible due to the nature and design of the units. Therefore, addition of the new UPS Room Fan Coil Units does not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.
l Ali of these changes are an enhancement to the UPS HVAC System and none of these changes affect the safety related Uninterruptible Power Supplies.
IMPLEMENTATION As mentioned in section (I) of this attachment, the design modifications which add the new UPS Room Fan Coil Units were reviewed and were found not l to create an unreviewed safety question or require a change to the Technical Specifications. All relevant issues were considered in this review including an update to the flooding analysis to include the potential for flooding due to the additional cooling water being located
! in the affected rooms. However, a review of the existing flooding l analysis indicates that if there were to be a chilled water leak, the amount of additional water into the rooms is so minimal that it is already enveloped by the existing flooding analysis for those areas. The need for automatic start on a Safety Injection Signal or a Black Out Signal was considered. Because an OPERABLE UPS Room Fan Coil Unit would already be running and would automatically restart when the emergency power bus was re energized (if power had been lost), the automatic start signals were found to be unnecessary. With the modifications installed. TU Electric will continue to remain compliant with the existing Technical Specifications until changed and system performance, reliability and capability to mitigate an accident are all enhanced.
In a similar manner TV Electric can implement and comply with the proposed Technical Specification changes even if the design modifications for the new UPS Room Fan Coil Units are not fully installed and operational. TV Electric can remain compliant with the LC0 by considering the UPS Room Fan Coil Units. inoperable and relying on the OPERABLE UPS A/C 1 Trains. As such, the proposed Actions and Surveillance Requirements are j correct and establish tle proper controls to ensure both safe normal
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} operation and the ability to safely shut down the plant in the event of a
- design basis accident. Station Blackout and Fire Protection are j unaffected.
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Attachment 2 to TXX 96405 Page 9 of 13 j
SUMMARY
l The new design of the UPS HVAC System with the addition of the new UPS Room Fan Coil Units is an enhanced design which provides better, more reliable support for the safety related equipment in the UPS &
Distribution Rooms. With the increased defense in depth with four independent UPS Room Fan Coil . Units, the potential for complete loss of room cooling is decreased from that considered in the current licensing basis. The revised specification provides plant specific controls to ensure the proper level of equipment availability consistent with ensuring safe normal operations of the units and the capability to detect and mitigate design basis accidents, including the potential for a design basis single failure. The ability to cope with station blackout and design basis fires is maintained or enhanced. The addition of the new UPS Room Fan Coil Units and proposeo revision to Technical Specification 3.7.11 continues to provide the desired level of safety, and overall, is considered an enhancement to safety.
The design of the new UPS Room Fan Coil Units incorporates existing licensing commitments of the CPSES fire protection program. Fire Safe Shutdown requirements have been identified and incorporated into the system design, consistent with the fire hazards analysis, fire safe shutdown analysis, and appropriate Design Basis Documents, to ensure adequate train separation and protection. The protection provided is adequate to operate the new units in a " stand alone" mode, without reliance upon the existing UPS HVAC system (which is also protected).
Combustible loading for the new UPS Room Fan Coil Unit is negligible due to the nature and design of the units. Therefore, the addition of the new UPS Room Fan Coil Units does not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.
All of these changes are an enhancement to the UPS HVAC system and none of these changes affect the safety related Uninterruptible Power Supplies.
ly SIGNIFICANT HAZARDS CONSIDERATION ANALYSES TU Electric has evaluated whether or not a significant hazards consideration is involved with the proposed changes by focusing on the three standards set forth in 10CFR50.92(c) as discussed below:
- 1) Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?
The UPS HVAC System is a support system for other safety related equipment, primarily the Uninterruptible Power Supplies and some of their distribution equipment. The only impact that this system can have on the probability or consequences of an accident must result from the failure of the system to provide adequate support to the supported safety related equipment when that supported safety related equipment is required to operate.
Attachment 2 to TXX 96405 Pag'e 10 of 13 Allowing same train cooling to satisfy the LC0 is considered equivalent to the existing Technical Specification. The proposed '
changes allow the use of the same train UPS Room Fan Coil Units or the same train UPS A/C Train to support a UPS & Distribution Room.
Surveillance requirements are added or modified to ensure that the i credited support equipment will be available when needed. i Unnecessary starts of the UPS A/C Trains have been eliminated from the specifications. Overall, this is considered an enhancement that I will increase the reliability of the UPS HVAC Systems. Because both !
the existing specification and the proposed revision to the specification continue to ensure normal support and the availability of at least one train of equipment in the event of a design basis accident, with the same or increased reliability, the consequences I of an accident previously evaluated is not affected. I Changing the specification from a " common" specification which impacts both units simultaneously to a specification which applies to both units separately is basically just an administrative change. 4 Having " common" specifications is an aid to the operator to provide ,
an alert that both units are affected. With the new LCO, both units l may not be affected because rooms may now be cooled separately.
Because both CPSES Units remain properly covered, however, this change will not significantly increase the probability of consequences of an accident.
The revision to the existing ACTION is considered equivalent except for the change of the Allowed Outage Time (A0T) from seven days to 30 days. This change is based on the significance of the heating and cooling function but does represent an increase in A0T and thus an increase in the probability that the supported functions could be unavailable. This increase is not considered significant based on the following several factors:
a) the systems design is based on a conservative assessment of the worst postulated conditions in the rooms; b) generally, less than design cooling is required and a short duration or partial failure may have little or no impact on the system's ability to perform its function:
c) the multiple backups available (two UPS A/C Trains and only one UPS Room Fan Coil Unit per each room) increase the potential of restoring additional cooling if needed:
d) the ability to perform alternate actions if normal cooling is lost such as circulating air via existing fans or portable fans thereby extending the time before cooling must be restored: and e) the extended A0T would allow more time and opportunity to perform corrective maintenance to ensure high equipment reliability.
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. Att.achment 2 to TXX 96405 Page 11 of 13 The new ACTION for loss of cooling reflects requirements that already exist in the Technical Specifications. The A0T for this l ACTION statement is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> which is based on the risk from an event occurring requiring the inoperable UPS A/C Train, and the remaining UPS Room Fan Coil Units and A/C Train fans providing the required protection.
The new ACTION for loss of cooling and ventilation reflects a conservative response to the potential impact of such a condition.
The proposed A0T is one hour. One hour is based on the time lag available from the operating temperature to the maximum Technical Specification limit of the UPS & Distribution Rooms. The addition of a specific ACTION in lieu of relying on Specification 3.0.3, although essentially equivalent, is consistent with the methodology of the improved Standard Technical Specifications and alerts the operator to the significance of the situation.
The changes made to the surveillance ensure that the UPS Room Fan Coil Units will operate. The UPS Room Fan Coil Units are connected l to the emergency busses and TS 4.8.1.1.2f. demonstrates the energization of emergency busses with permanently connected loads. l The changes made to the 18 month surveillances on the UPS A/C trains were changed from the Safety Injection signal with the Blackout Test signal to "... actual or simulated actuation signal". This is I consistent with NUREG 1431, " Standard Technical Specifications I Westinghouse Plants".
The changes to the BASES are descriptive in nature to reflect the other changes and by themselves have no impact on the probability or consequences of an accident.
The ability to cope with station blackout and design basis fires is maintained or enhanced. For station blackout coping, the UPS A/C fans are considered to remain available while additional cooling is provided by a single available Fan Coil Unit.
In summary, the proposed changes take advantage of the increased reliability offered by the revised system design. It also maintains the level of support provided by the system while at worst, allowing a slight decrease in availability (in certain situations) which is I not considered significant. As a result, it is concluded that none of the changes made to the existing Technical Specification involve a significant increase in the probability or consequences of an accident previously evaluated.
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' Attachment 2 to TXX 96405 Pag'e 12 of 13 l 2) Do the proposed changes create the possibility of a new or different kind of accident from any previously evaluated?
Revising this specification to take credit for the new UPS Room Fan Coil Units, to take credit for same train UPS A/C Train support for a UPS and Distribution Room, to make the specification unit specific instead of common, to make the surveillances appropriate for the credited equipment, and to make the action statements appropriate for the credited equipment and their significance, does not by itself alter plant hardware. Plant procedures are only altered to
, the extent that the revised specification will allow different l configurations of equipment in the UPS HVAC System to be operated at L different times. These changes ensure continued support of the. !
safety related equipment in the affected areas and do not affect the equipment's failure or failure modes. As a result, these changes to the Technical Specification do not create the possibility of a new or different kind of accident from any previously evaluated.
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l 3) Do the proposed changes involve a significant reduction in a margin l
of safety?
None of the changes being proposed alter the environmental conditions which are to be maintained in the areas supported by an OPERABLE UPS HVAC System during normal operations and following an accident. As a result, the margin of safety for these functions remains the same. The only potential adverse impact is the system's postulated availability, as discussed in the response to question 1 i above. This reduction in availability is to a great extent mitigated by the projected increase in system reliability. As noted in the response to question 1, there is no significant impact on the accident analyses. Thus, even if system availability issues were considered an aspect of margin of safety, the proposed changes do not involve a significant reduction in margin of safety.
Based on the above evaluations TV Electric concludes that the activities associated with the above described changes present no significant hazards consideration. The proposed LCO described above is consistent with the standards set out by 10 CFR 50.92(c) and accordingly, a finding by the NRC of no significant hazards consideration is justified.
L ENVIRONMENTAL EVALUATION l TU Electric has evaluated the proposed changes and has determined that the i changes do not involve (1) a significant hazards consideration. (ii) a
- j. significant change in.the types or significant increase in the amount of effluent that may be released offsite, or (iii) a significant increase in the individual or cumulative occupational radiation exposure.
i Accordingly, the proposed changes meet the eligibility criterion for
- categorical exclusion set forth in 10CFR51.22 (c). Therefore, pursuant to f
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, Attachment 2 to TXX 96405 Page 13 of 13 10CFR51.22 (b), an environmental assessment of the proposed changes is not required.
- 11. REFERENCES
February 1993. (Updated through License Amendments 42/28). l
- 2. NUREG - 1431, " Standard Technical Specifications Westinghouse Plants", Revision 1, April 1995.
- 3. NUMARC 87 00, " Guidelines and Technical Bases for NUMARC :
Initiatives Addressing Station Blackout at Light Water !
Reactors" Rev. 1, August 1991.
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