ST-HL-AE-5652, Provides Clarification of Philosophy for Adapting Std W Improved Specifications to STP three-train ESF Configuration,Per NUREG-1431

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Provides Clarification of Philosophy for Adapting Std W Improved Specifications to STP three-train ESF Configuration,Per NUREG-1431
ML20140E015
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 06/02/1997
From: Martin L
HOUSTON LIGHTING & POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-1431 ST-HL-AE-5652, NUDOCS 9706110193
Download: ML20140E015 (16)
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The Light c o mp a n yS uth Texas Project Electric Generating station P. O. Box 289 Wadsworth, Texas 77483 ston @Q & Pm i

June 2,1997 ST-HL-AE-5652 l

File No.: G20.01, G20.02 10CFR50.90 U.S. Nuclear Regulatory Commission Attention: Document Control Desk  !

Washington, DC 20555 South Texas Project Unit I and Unit 2 Docket Nos. STN 50-498 and 50-499 Supplementary Information re South Texas Project Pronosed Imnroved Technical Specifications

References:

1. Letter dated November 27, 1996 from William D. Beckner (NRC) to William T. Cottle (HL&P) entitled " Staff Comments on the South Texas Application for Conversion to the Improved Standard Technical I Specifications (TAC Nos. M95529 and M95530)".
2. Letter dated February 11, 1997 from Lawrence E. Martin (STP) to Document Control Desk entitled Supplementary Information re South Texas Project Proposed Improved Technical Specifications (ST-HL-AE-5517).

Representatives of the South Texas Prc, Net met with the Nuclear Regulatory Commission staff on April 3,1997 to discuss the review of the South Texas Project proposed Improved Technical Specifications. The meeting provided useful insights to facilitate the review and i approval of the STP proposed Improved Technical Specifications by the NRC staff. As discussed in the meeting, STP is providing a clarification of the philosophy for adapting the Standard Westinghouse Improved Specifications (NUREG-1431) to the STP three-train Engineered Safety Feature configuration.  !

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Houston Lighting & Power Company

) South Tomas Project Electric Generating Station ST-HL-AE-5652 l

File No.: G20.01,  ;

G20.02 i

Page 2 i s .

' As discussed iri Reference 2 and in the April 3 meeting, the South Texas Project plans to  !

submit a comprehensive supplement to its initial application by June 30, 1997. This I comprehensive supplement will address NRC comments and issues identified in Reference 1 and the " pilot" supplement submitted in Reference 2. It will also include the incorporation of amendments to the current Technical Specifications, a Relocation Matrix describing where information relocated from the Technical Specifications was placed, a disposition of proposed generic changes (TSTFs), and a list of pending and planned changes to the STP Technical Specifications.

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Following resolution of any remaining NRC comments, STP will submit a certified Proof {

and Review version of the Improved Technical Specifications targeted to support NRC approval

{, of the proposed amendment by the end of 1997.

, Ifyou have any questions, please contact Mr. A. W. Harrison at 512-972-7298 or Mr. M. A. McBumett at 512-972-7206.

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l Lawrence E. M m

' General Manage ,

Nuclear Assurance and Licensing JMP/

Attachments: 1. Clarified South Texas Project Philosophy for Incorporating Three Train Design into Improved Technical Specifications

2. Table 1 - STP Improved Technical Specification Allowed Outage Times i 4

1 c:\wp\nParc-wk\ misc.97\5652. doc STI: 30287594 4

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f ST-HL-AE-5652 IIouston Lighting & Power Company File No.: G20.01 South Texas Project Electric Generating Station G20.02 Page 3 Rufus S. Scott Ellis W. Merschoff Associate General Counsel Regional Administrator, Region IV llouston 1.ighting & Power Company U. S. Nuclear Regulatory Commission P. O. Box 61067 611 Ryan Plaza Drive, Suite 400 Ilouston, TX 77208 Arlington, TX 76011-8064 Institute of Nuclear Power Thomas W. Alexion Operations - Records Center Project Manager, Mail Code 13H3 700 Galleria Parkway U. S. Nuclear Regulatory Commission Atlanta, GA 30339-5957 Washington, DC 20555-0001 Dr. Benram Wolfe David P. Loveless 15453 Via Vaquero Sr. Resident Inspector Monte Sereno, CA 95030 c/o U. S. Nuclear Regulatory Comm.

P. O. Box 910 Richard A. Ratliff Bay City, TX 77404-0910 Bureau of Radiation Control Texas Department of Ilealth J. R. Newman, Esquire 1100 West 49th Street Morgan, Lewis & Bockius Austin, TX 78756-3189 1800 M Street, N.W.

Washington, DC 20036-5869 J. R. Egan, Esquire Egan & Associates, P.C.

M. T.11ardt/W. C. Gunst 2300 N Street, N.W.

City Public Service Washington, D.C. 20037 P. O. Box 1771 San Antonio, TX 78296 U. S. Nuclear Regulatory Commission J. C. Lanier/M. B. Lee Attention: Document Control Desk City of Austin Washington, D.C. 20555-0001 Electric Utility Depanment 721 Barton Springs Road Austin, TX 78704 Central Power and Light Company ATTN: G. E. Vaughn/C. A. Johnson P. O. Box 289, Mail Code: N5012 Wadsworth, TX 77483 1

Attachment 1 ST-IIL-AE-5652

,, Page1of3 Clarified South Texas Project Philosophy for Incorporating Three Train Design into Improved Technical Specifications This attachment describing the South Texas Project (STP) philosophy for incorporating the STP three train design into the Improved Technical Specifications (ITS) has been revised to address NRC comments provided at the April 3,1997 meeting. This description was originally attached to STP's letter to the NRC dated February 11,1997.  !

The Standard Improved Technical Specifications w:re written for standard plants with two trains of Engineered Safety Feature (ESF) equipment. For such standard plant designs, the j safety functions are degraded (loss of single failure protection) when a single train of an ESF 1 function is inoperable, and there is a loss of safety function when two trains of an ESF function  !

are inoperable. Consequently, there is generally no allowed outage time in the Standard Technical Specifications for situations where two trains of an ESF function are inoperable.

The South Texas Project has three trains of ESF equipment and ESF suppon equipment.

Therefore, when only one of the three ESF trains is inoperable, STP retains a high degree of redundancy, which is substantially greater than for a two-train plant during conditions where one ESF train is inoperable. In addition, unlike a two-train plant, STP does not experience a complete loss of safety function when two of three trains of an ESF function are inoperable.

Thus it is appropriate for STP to have extended allowed outage times when one of three trains is inoperable and a reasonable allowed outage time for conditions where two of three trains are inoperable.

Generally, the conversion of a two train Standard Improved Technical Specifications to Improved Technical Specifications suitable for a three train plant involves application of the three concepts described below. These concepts are generally applied throughout the South Texas ITS submittal with some adjustment for specific system designs and redundancies. In each case, the deterministic conclusion has been tested with the Probabilistic Safety Assessment (PSA) to account for integrated effects and to ensure there is appropriate probabilistic justification.

Concepts for Converting Two Train Technical Specifications to Three Train Technical Specifications:

l. Two train specifications have action statements that cover the progression from all i trains available to no trains available. To convert from two train specifications to I

three train specifications, it is necessary to add action statements to cover the pmgression from three trains available to no trains available.

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t Attachment 1 ST-HL-AE-5652

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2. The three train plant has substantially more capability to mitigate design basis events (including single failures) with one train out of service than a two train 3

plant with one train out of service (i.e., no single failure mitigation capability).

The allowed outage times (AOTs) associated with the loss of'one train are increased based on this additional capability.

f 3. The three-train plant has capability to mitigate most design basis events without a

! single failure if two trains are out of service wlmre the two-train plant has no

} capability with two trains out of service. This additional capability warrants 4

provision of short AOTs in lieu of immediate shutdown requirements.

Consequently, AOTs are provided for two trains out of service.

STP has structured'its application for Improved Technical Specifications to incorporate the three train design concepts described above. The first entry in Table 1 below outlines a general comparison between the philosophy of a typical two-train plant and a three-train plant.

The time allowed to be in a condition with less than three trains operable is based on a reasonable time to restore operability and the capability of the remaining operable equipment. The STP Probabilistic Safety Assessment (PSA) shows that the risks incurred by the proposed allowed 3

outage times are acceptable and consistent with guidance contained in the EPRI PSA Application Guide. It is also important to note that a condition where two of three trains are inoperable would be an unexpected, involuntary condition since STP would not normally plan to remove two trains from service. (A detailed discussion of the application of the STP PSA for establishing a technical basis for extended allowed outage times in the STP Improved Technical Specifications is provided in the Topical Report that accompanied the original STP application for the Improved Technical Specifications.)

l Table 1 describes the changes to the allowed outage times that are being proposed in the STP Improved Technical Specification submittal. The values in'" bold italics" denote proposed changes to the current Technical Specification requirements. The Auxiliary Feedwater System (AFW) is included for completeness, although it is a four-train system at STP. The general l philosophy is still applicable since AFW is usually a three-train system at a " standard" plant. It l

can be seen that the philosophy described in the first " general case" entry has been incorporated '

in the proposed changes. In some cases, the proposed changes are more restrictive than the i

current Technical Specifications, which reflects the incorporation of risk informed elements used '

to develop the technical basis for the proposed allowed outage times. (Note that Table 1 is for illustrative purposes and does not include all the detail of the specification requirements.)

The deterministic bases for the proposed allowed outage times have been described to the NRC staff in STP's application for extended allowed outage times for its standby diesel generators, Essential Cooling Water System, and Chilled Water System. This application was  !

approved in Amendments 85 and 72 to the STP Unit I and Unit 2 Operating Licenses, respectively. '

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Attachment 1 ST-HL-AE-5652 i -

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4 In that application and supporting correspondence, STP described the capabilities of a single train of ESF equipment to mitigate design basis accidents. Because the governing event is a condition where only one train of ESF equipment is postulated to be available, the analyses and evaluations performed in support of Amendments 85 and 72 are directly applicable to the j evaluations of the changes to the allowed outage times being proposed in the Improved Technical

Specifications. The results of the deterministic evaluation done in support of those amendments show that with only one train of ESF equipment available, and allowing for some operator i

actions, STP can mitigate nearly all design basis events. STP is proposing no configurations in the Improved Technical Specifications that are not bounded by the evaluations for Amendments j 85 and 72.

4 i Staggered Testing at the South Texas Project

! The South Texas Project will include the definition of staggered test basis in our j Improved Technical Specifications. The frequencies will be adjusted to account for the three i

train design (four Auxiliary Feedwater trains). Variation from the standard is typically only a j few days. The proposed alternative for the frequency continues to meet the intent of the definition for staggered testing.

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TAELE1 .

STP IMPROVED TECHNICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 1 of10)

System / Condition Standard Two . Current STP Three Proposed STP Safety Comparisom ' Three Train Comments Train Specification Train Specification Three Train Specification General Case All Trains Operable Unlimited Unliniited Unlimited Two train and three train meet design basis, including single failure criteria.

I Train Inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (typ.) 7 days (typ.) 7 days or greater 2-train clant: no loss of safety Capabilities exceed those of a function, but does not meet two-train plant. Action times of single failure criteria. 7 days (or grea. r in some cases) are appropriate.

STP (3 train =): no loss of safety function; meets single failure criterie in most cases.

2 Trains Inoperable T.S 3.03 or T.S. 3.03 or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train olant: complete loss of STP's capabilities exceed those equivalent equivalent (typ.) safety function and non-accident of a 2-train plant. 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> safe shutdown capability. allowed outage time recognizes +

the capabilities and limitations STP (3 trainth loss of safety and provides reasonable time to function only for specific low take corrective actions probability events; retains safe shutdown capability for non-accident conditions.

3 Trair Inoperable NA T.S.3.03 or T.S. 3.03 or Loss of safety function equivalent equivalent t

TABLEI STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 2 of10) -

System /Coedition - Standard Two Current STP 7hree Proposed STP Safety Comparison Thute Train Comedets Train Specification Train SpecificaLon Thrte Train -

Specifation Safety injection (STS 3.5.2) (CIS 3.5.2) (ITS 3.5.2)

All Trains Operable no action no action no action 1 Train Inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days 7 days 2-train plant: no loss of safety 7 days is unchanged from function, but does not meet Current Tech Specs. No new single failure criteria. extension is proposed in ITS.

STP (3 traind: no loss of safety function, meets single failure except for specific low probability events.

2 Trains Inoperable T.S. 3.03 T.S. 3.03 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train plant: complete loss of STP's capabilities exceed those safety function. of a 2-train plant. 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed outage time recognizes

_STP (3 traind: loss of safety the capabilities and limitations function only for specific low and provides reasonable time to probability events. take corrective actions 3 Trains Inoperable NA T.S. 3.03 T.S. 3.03 Loss of safety function

TABLEI .

STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 3 of10) '

System / Condition Standard Two Current STP Three Proposed STP Safety Comparison Three Train Consueemts Train Specification Train Specification Three Train -

Specirication Essestial Cooling (STS 3.7.8) (CTS 3.7.4) (ITS 3.7.8)

Water:

All Trains Operable no action no action no action I Train Inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days 7 days 2-tram plant. no loss of safety 7 days is unchanged from j function, but does not meet Current Tech Specs. No new single failure criteria. extension is proposed in ITS.

STP (3 traim): no loss of safety function, generally meets single failure for most probable design ,

basis events.

2 Trains Inoperable T.S. 3.0.3 T.S. 3.0.3 24 kones 2-train olant: complete loss of STP's capabilities exceed those safety function and non-accident of a 2-train plant. 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> safe shutdown capability. allowed outage time recognizes  ;

the capabilities and limitations STP (3 trains): can meet almost and provides reasonable time to all its safety design bases with take corrective actions.

only one operable train, including all of the more probable accidents and anticipated operational occurrences as defined in Appendix A to 10 CFR Part 50.

3 Trains Inoperable NA T.S. 3.0.3 T.S. 3.0.3 Loss of safety function

TABLEl-

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STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 4 of10) -

System / Condition Standard Two Current STP Three Proposed STP Safety Comparison Three Train Comments Trals Specification Train Specification Three Train '

Specification Essential Chilled (STS no spec) (CTS 3.7.14) (ITS 3.7.10)

Water All Trains Operable no action no action I Train Inoperable 7 days 7 days 2-train niant: no loss cf safety 7 days is unchanged from function, but does not meet Current Tech Specs. No new single failure criteria. extension is proposed in ITS STP (3 trains): no loss of safety function, generally meets single failure for most probable design basis events.

2 Trains inoperable T.S. 3.03 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train olant: complete loss of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is consistent with safety function and non-accident Essential Cooling Water safe shutdown capability, specification and recognizes reasonable time to take STP (3 trainst can meet almost corrective action.

all its safety design bases with i only one operable train, including all of the more probable accidents and anticipated operational occurrences as defined in Appendix A to 10 CFR Part 50.

3 Trains Inoperable T.S. 3.03 T.S. 3.03 Loss of safety function

TABLEI '

STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES

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Systesi/ Condition Standani Two Current STP Three - Proposed STP . Safety Comiparison nree Trais Comissents Train Specification Train Specification Three Train t Specification Control Roose (STS 3.7.10) (CTS 3.7.7) (ITS 3.7.1I)

Envelope HVAC '

(MODE 1-4)

All Trains Operable no action no action no action i Train Inoperable 7 days 7 days 7 days 2-train plant: no loss of safety 7 days unchanged from Current function, but does not meet Tech Specs single failure criteria.

STP (3 trains): no loss of safety function, generally meets single ,

failure although system may not be able to maintain 1/8" positive pressure in all areas with a single train 2 Trains Inoperable TS 3.03 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> N hosers 2-train olant: complete loss of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> reflects a reduction of safety function. allowed time based on risk insights from the STP PSA and STP (3 trains): system is is consistent with the general functional although it may not case.

be able to maintain 1/E positive pressure in all areas.

3 Trains Inoperable NA TS 3.0.3 TS 3.03 Loss of safety function I .

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TABLE 1 .

STP IMPROVED TECHNICAL SPECIFICATION ALLOWED OUTAGE TIMES '

(Page 6 of10)

Systean/ Condition Standard Two Current STP Three Pmposed STP . - Safety Coasparison Three Train Cossaments Traia Specification Train Specification Three Train Specification Comeposest (STS 3.7.7) (CIS 3.73) (ITS 3.7.7)

Cooling Water:

All Trains Operable no action no action no action I Train inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days 14 days 2-tram plant no loss of safety STP proposes to increase the function, but does not meet allowed outage time from 7 days single failure criteria. to 14 days since only one train of CCW is necessary to fulfill STP (3 traine): no loss of safety the safety function.

function and pr rally meets single failure with rppropriate operator action.

2 Trains Inoperable T.S. 3.03 T.S. 3.03 24 howrs 2-train plant: complete loss of STP's capabilities exceed those -

safety function and non-accident of a 2-train plant. 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> safe shutdown capability. allowed outage time recognizes i

the capabilities and limitations  :

STP (3 traint): can meet almost and provides reasonabic time to all its safety design bases with take corrective actions.

only one operable train assuming appropriate operator action.

3 Trains Inoperable NA T.S. 3.03 T.S. 3.03 Loss of safety function

TABLEI .

STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 7 of10)

System / Condition . Standard Two Current STP Three Proposed STP Safety Comparison Three Train Comme'ats Train Specification - ~ Train Specification Three Train Specification Residual Heat (STS 3.5.2, treated (CTS 3.5.6) (ITS 3.52)

Removal as ECCS)

All Trains Operable No action No action No action 1 Train inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days H days 2-tram plant. no loss of safety STP proposes to extend the function, but does not meet allowed outage time to 14 days single failure criteria. based on the redundancy of the 3 trains of RHR and the STP (3 traint): no loss of safety functional redundancy of the function; generally meets single Low Head Safety injection failure and Low Head Safety (LHSI). RHR at STP is not an injection provides functional ECCS injection system. It redundancy. functions solely for the long-term removal of decay heat after the RCS is depressurized for both normal operation and post-accident conditions. LHSI is capable of performing the long-term cooling under post-accident conditions.

2 Trains inoperable TS 3.0.3 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train olant: complete loss of STP's capabilities exceed those safety function and non-accident of a 2-train plant. 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> safe shutdown capability. allowed outage time recognizes the capabilities and thitations STP (3 trainth can meet almost and provides reasonable time to all its safety design bases with take corrective actions only one operable train.

3 Trains inoperable NA Immediately take immediately take Reflects Current Tech Specs.

action to restore action to restore Appropriate action is to take action to restore since a shutdown would place the plant in a condition where the inoperable system #would be ,

needed.

TABLE 1 ,

STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page 8 of10)

  • System / Condition Standani Two Current STP Three . Proposed STP Safety Comparison Three Train Comments Train Specification Train Specification Three Train Specificatica Reactor (STS 3.6.6A) - (C13 3.6.23) (113 3.6.6) SIP PSA analysis shows that Containment Fan RCFCs and Contamment Spray Coolers are not risk-significant systems.

All Trains Operable No action No action No action I Train Inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days 28 days 2-train niant: no loss of safety 28 days is proposed for one train function, but does not meet out of service based on STP single failure criteria. analysis that shows that the system has substantial STP (3 traimt no loss of safety redundancy.

function; generally meets single failure criteria.

2 Trains Inoperable 7 days TS 3.03 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train plant: complete loss of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is a reasonable time for safety function. corrective action for conditions with two trains of RCFCs STP (3 trains): one train inoperable.

maintains the function although Control Room and Technical Support Center doses will increase under design basis accident conditions.

3 Trains Inoperable NA TS 3.03 TS 3.03 Loss of safety function

TABLEI STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES

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System / Condition ' Standard Two Carerat STPThree ' Proposed STP Safety Comparison -Three Train Comments Train Specification Train Specification Three Train Specification Containment Spray (STS 3.6.6A) (CTS 3.6.2): (ITS 3.6.6) STP PSA analysis shows that RCFCs and Containment Spray are not risk-significant systems.

All Trains Operable No action No action No action i Train Inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 7 days 23 days 2-train olant: no loss of safety 28 days is proposed for one train function, but does not meet out of service based on STP single failure criteria. analysis that shows that the containment retains substantial  ;

STP (3 trains): no loss of safety margin for design basis events function; generally meets single where one or more trains of failure criteria. containment spray are postulated to fail.

2 Trains Inoperable TS 3.0.3 TS 3.0.3 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2-train plant: complete loss of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is a reasonable time for safety function. corrective action for conditions with two trains of containment STP (3 traint): one train spray inoperable maintains the function although Control Room and Technical Support Center doses will increase under design basis accident conditions. >

3 Trains Inoperable NA TS 3.0.3 TS 3.0.3

TABLE 1 .

STP IMPROVED TECIINICAL SPECIFICATION ALLOWED OUTAGE TIMES (Page100fl0) '

SystendCondities Standard Two Train Current STP Dree Proposed STP Three Comments ' Three Train Ceanments s Specifiestion Train Specifiestion Train Specification  ;

Auxiliary (STS 3.7.5) (CTS 3.7.1.2) (ITS 3.7.5) STP has 3 motor driven trains of Feedwater AFW and I turbine driven AFW train. **

All Trains Operable No action No action No action I Train inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />' 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 28 days Standard Plant no loss of safety STP's Auxiliary Feedwater design function, but consideration of single is essentially the " standard plant" ,

  • 7 days if the steam (no distinction between failure results in increased with an extra motor driven train of '

supply to the turbine motor driven and dependency on the turbine-driven Auxiliary Feedwater. STP proposes driven train is turbine driven trains) train. that 28 days be allowed for the inoperable " extra" train to be inopersle. One ,

SIE: no loss of safety function. of four AFW trains must operate e Single failure does not result in and deliver flow to its respectise increased dependence on the Steam Generator for success. "

turbine-dri en train because of the third motor-driven train.

21 rains inoperable 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 6 hobrs' 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Standard Plant: function may be STP has substantially greater lost if loss of off-site power is the capability than the Standard Plant.

  • 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> if the (no distinction between initiating event. The 72-hour proposed allowed combination includes motor driven and outage time is consistent with the the A train motor turbine driven trains) SIP; STP still has two trains of allowed outage time of a Standard driven AFW Auxiliary Feedwater operable, Plant with the same number of either of which is capable of operable trains (2). For an ATWS removing decay heat. event two of four AFW trains are required for success. "

3 Trains Inoperable immediately take 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Standard Plant: function is lost. STP has substantially greater action to restore capability than the Standard Plant.

SIE; function is not lost. One train The 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> proposed allowed is still operable and capable of outage time is consistent with the removing decay heat. allowed outage time of a Standard Plant with the same number of onerable trains (l).

41 rains Inoperable NA Immediately take immediately take Function is lost.

action to restore action to restore

" - STP analysis shows that there is no significant difTerence between a motor-driven train being out of service or the turbine-driven train being out of service.

STP has a unique Westinghouse design, in that, each AFW has a 100% capability to their respective Steam Generator.

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