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#REDIRECT [[ST-HL-AE-5652, Provides Clarification of Philosophy for Adapting Std W Improved Specifications to STP three-train ESF Configuration,Per NUREG-1431]]
| number = ML20140E015
| issue date = 06/02/1997
| title = Provides Clarification of Philosophy for Adapting Std W Improved Specifications to STP three-train ESF Configuration,Per NUREG-1431
| author name = Martin L
| author affiliation = HOUSTON LIGHTING & POWER CO.
| addressee name =
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000498, 05000499
| license number =
| contact person =
| case reference number = RTR-NUREG-1431
| document report number = ST-HL-AE-5652, NUDOCS 9706110193
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE
| page count = 16
}}
 
=Text=
{{#Wiki_filter:.
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.                                                                                    !
                                                                                                                                \'
9706110193 970602 PDR    ADOCK 05000498                                        *'*            lh P                            pyg 00G1                    r oject u. . . Bes ir or ine r eticie ts i the so ia Texas e<ejeet e:\mp\nl\nrc-wk\ misc-97\$652. doc                                                                sTI: 30287594
 
l 1
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.
I I
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.
i 4
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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.
I i
 
t Attachment 1 ST-HL-AE-5652
                            ,,                                                                          Page 2 of 3 1
: 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.                                                                                              '
l
: i.            .
Attachment 1 ST-HL-AE-5652 i                -
                          ,,                                                                  Page 3 of 3 1
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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I                                                                                                                            i l
i I
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l U                                                                                                                  . -  _
 
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 hours (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 hours              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 hour 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 hours              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 hours                    2-train plant: complete loss of                                                                        STP's capabilities exceed those safety function.                                                                                        of a 2-train plant. 24 hour 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 hours            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 hour 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-
                                                                                                                                                                                                                                                                                                                                                        ~
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 hours                                                                                  2-train olant: complete loss of                                                                              24 hours 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
                                                                                                                                                                                                                  ~.
(Page 5 of10)
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 hours                                                  N hosers                        2-train olant: complete loss of 24 hours 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    .
t
 
                                                                                                                                                                  . ~ ~ . _ _ -                  . _ - .                  __.        .          .                          .                                            .          -                  -
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 hours                                                                                                                                            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 hour 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 hours                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 hours                                          24 hours              2-train olant: complete loss of      STP's capabilities exceed those safety function and non-accident    of a 2-train plant. 24 hour 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 hours            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 hours                  2-train plant: complete loss of                                        24 hours 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
                                                                                                                                                                                                  ~
(Page 9 of19)
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 hours                      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 hours            2-train plant: complete loss of    24 hours 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 hours'                  72 hours                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 hours                    6 hobrs'                72 hours                      Standard Plant: function may be                                  STP has substantially greater lost if loss of off-site power is the                          capability than the Standard Plant.
* 72 hours 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 hours                6 hours                        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 hour 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.
                                                                                            . - _ . _ _ . _.          . . _ _ _ _ .            . _ _ _ _ _ _          _ _ -      _ - . _ .          _    _ _ _ _      . - - _ _ _ _ _ _ _ _ _ _ _}}

Latest revision as of 14:19, 8 August 2022

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