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{{Adams
#REDIRECT [[IR 05000498/1999004]]
| number = ML20205A160
| issue date = 03/24/1999
| title = Insp Repts 50-498/99-04 & 50-499/99-04 on 990222-25. Violations Noted.Major Areas Inspected:Maint
| author name =
| author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
| addressee name =
| addressee affiliation =
| docket = 05000498, 05000499
| license number =
| contact person =
| document report number = 50-498-99-04, 50-498-99-4, 50-499-99-04, 50-499-99-4, NUDOCS 9903300308
| package number = ML20205A123
| document type = INSPECTION REPORT, NRC-GENERATED, TEXT-INSPECTION & AUDIT & I&E CIRCULARS
| page count = 12
}}
See also: [[see also::IR 05000498/1999004]]
 
=Text=
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                                            ENCLOSURE
                        U.S. NUCLEAR REGULATORY COMMISSION
                                            REGION IV
        Docket Nos.:    50-498;50-499
        License Nos.:  NPF-76; NPF-80
        Report No.:    50-498/99-04;50-499/99-04
        Licensee:      STP Nuclear Operating Company
        Facility:      South Texas Project Electric Generating Station, Units 1 and 2
        Location:      FM 521 - 8 miles west of Wadsworth
                        Wadsworth, Texas
        Dates:          February 22 to 25,1999
        Inspectors:    P. Gage, Senior Reactor inspector, Operations Granch
                        P. Balmain, Operations Engineer, Office of Nuuoar Reactor Regulation
                        P. Wilson, Senior Reactor Analyst, Office of Nuclear Reactor Regulation
        Approved By:    Dr. Dale A. Powers, Chief, Engineering and Maintenance Branch
                        Division of Reactor Safety
        ATTACHMENT:    Supplemental Information
                                                                                                                        i
                                    "
    9903300300 990324
    PDR    ADOCK 05000498
    G                PDR
 
                                                                                                            __
,
    .
  .
                                                          2
                                              EXECUTIVE SUMMARY
                        South Texas Project Electric Generating Station, Units 1 and 2
                            NRC Inspection Report No. 50-498/99-04; 50-499/99-04
      The licensee had developed and implemented a prograrn in accordance with 10 CFR 50.65,
      " Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants." One
      Non-Cited Violation of the Maintenance Rule was identified.
      Maintenance
      a
              !nspectors identified inadequate reliability performance measures for eight plant risk-
              significant systems. As a result of the inadequate performance measures, the 480Vac
              load center system for both units was allowed to degrade beyond the probabilistic risk
              assessment assumed performance without the licensee having provided Odequate
              technical justification for not having established goals, or appropriate corrective actions.
              This was a Severity Level IV violation of the Maintenance Rule and is being treated as a
              Non-Cited Violation, consistent with Appendix C of the NRC enforcement policy
              (EA 99-058). This violation is in the licensee's corrective action program as documented
              by Condition Record 99-2925 (Section M1.2).
                                                                                                              i
3
                                                                                                              l
                                                                                                              1
u
 
,
    -
                                                                                                            i
                                                                                                            j
                                                            3-
                                                    Report Details                                          !
      Summarv of Plant Status
      During the inspection week, Units 1 and 2 operated at or near full power.                            t
                                                                                                            i
      Backaround
      The licensee had implemented a Maintenance Rule program that endorsed the guidance of                q
      Regulatory Guide 1.160," Monitoring the Effectiveness of Maintenance at Nuclear Power                1
      Plants," and NUMARC 93-01 " Industry Guideline for Monitoring the Effectiveness of
      Maintenance at Nuclear Power Plants," with some exceptions noted. NRC Inspection                    h
      Report 50-498;-499/98-01 documented the results of the Maintenance Rule baseline team
      inspection.
                                                    II. Maintenance
      M1      Conduct of Maintenance
      M1.2 Safety or Risk Determination
      a.      Insoection Scope (62706 and 92902)
                The inspectors reviewed sensitivity studies that tb      nsee had completed to assess
                the risk contribution from the postulated unavailatt, .I 9 of the 21 risk significant
                systems that were the subject of this inspection. The licensee representative had stated
                that the postulated unavailability of these systems would not significantly contribute to
                the overall core damage frequency and, therefore, provided an additional basis for not
                monitoring unavailability for these systems. The inspectors also reviewed the adequacy      i
                of reliability performance criteria for several systems to determine if the licensee's      f
                probabilistic risk assessment reliability assumptions were preserved.                      J
      b.      Observations and Findinas                                                                    I
      b.1      Unavailability Sensitivity Studies
                The licensee performed unavailability sensitivity studies on nine risk-significant systems. I
                These studies were documented in the licensee's Analysis / Assessment Sequence
                Numbers PSA-98-05, PSA-98-06, PSA-98-10, and PSA-99-01. The plant systems
                included in these studies were as follows:                                                  ,
                .        Qualified Display Processing System (AM)
                .
                        125Vdc Class 1E (DJ)
                .        Main Steam Syctem (MS)
                .        4.16kVac Class 1E Power System (PK)
                -      Reactor Coolant System (RC)
              ,
  ..
 
r
  ,
                                                  -4-
        .          Reactor Control System (RS)
        -          Engineered Safety Features System (SF)
        .          Solid State Protection System (SP)
        .          120Vac Class 1E Power System (VA)
        The inspectors noted that these studies evaluated the potential change in core damage
        frequency if the probabilistic risk assessment assumptions for unavailability of these
        systems were doubled. In each study, the inspectors found that the licensee had
        performed full probabilistic risk assessment requantifications. The inspectors reviewed
        one additional sensitivity study where the licensee requantified their probabilistic risk
        assessment with a postulated solid state protection system unavailability that was
        17 times greater than the nominal probabilistic risk assessment solid state protection
        system unavailability. The inspectors observed that in all instances, the change in core
        damage frequency was small (less than 1 percent).
        The inspectors also compared recent actual maintenance unavailability for these
        systems with the values assumed in the licensee's probabilistic risk assessment and
        found them to be reasonably close in value. Based on the inspectors' review of the
        licensee's sensitivity studies, the inspectors concluded that the licensee had adequately
        demonstrated that the postulated unavailability of these systems did not significantly
        contribute to the overall core damage frequency.
    b.2 Reliability Performance Criteria
        NUMARC 93-01," Industry Guideline For Monitoring the Effectiveness of Maintenance at
        Nuclear Power Plants," Revision 2, Section 9.3.2, states, in part, ". . . that performance
        criteria for risk-significant SSCs should be established to assure that reliability and
        availability assumptions used in the plant-specific PRA, IPE, IPEEE, or other risk            I
        determining analysis are maintained or adjusted when determined necessary by the
        utility." In general, the inspectors found that the licensee nad established two reliability
        performance criteria for each plant system. These were Maintenance Rule functional          i
        failures and probabilistic safety assessment functional failures. The licensee              )
        representative stated that the probabilistic safety assessment functional failure was the
        criterion that assured that the probabilistic risk assessment reliability assumptions were
        maintained. The inspectors observed that there were eight risk-significant systems
        where the licensee had not established probabilistic safety assessment functional failure    ,
        performance criteria, in addition, the inspectors noted that the Maintenance Rule            I
        functional failure performance criteria established for those systems did not appear to
        preserve the probabilistic risk assessment reliability assumptions. As a result of this
        observation, the licensee initiated corrective action and documented the problem in
          Condition Record 99-2r48. The licensee promptly performed the necessary analyses to
        establish appropriate probabilistic safety assessment functional failures for these
          systems. The results nf these analyses along with the Maintenance Rule functional
          failure performance criteria are documented in the table below.
L
 
e ,    _
      +
    .
                                                            5-
          x
                      System                        MRFF Criteria                        New PSAFFs
                Instrument Air :          5/ unit /18 months                          3/ unit /18 months
                Qualified Display          6/ unit /18 months                          3/ unit /18 months
                Processing -                                  '-
                480Vac 1E Load            5/ train /18 months or 7/ unit /18 months  1/ unit /18 months
                Centers .
                480Vac Non-Class          2/ unit /18 months                          1/ unit /18 months
                1E Load Center
                480Vac Class 1E            8/ train /18 months or 15/ unit /18 months  4/ unit /18 months
                Motor Control
                Centers
                Reactor Control -          2/ unit /18 months                          1/ unit /18 months
                System
                Solid State Protection    3/ unit /18 months                          1/ unit /18 months
                120Vac Vital Power'        3/ unit /18 months                          2/ unit /18 months
              Based on the results of the licensee's analyses, the inspectors concluded that the
              Maintenance Rule functional failure reliability performance criteria did not assure that the
            '
              licensee's probabilistic risk assessment reliability assumptions were maintained and,
              therefore, the reliability performance criteria established for these systems were
              inadequate.
              10 CFR 50.65 (a)(1) states, in part, that ". . . licensees shall monitor the performance or
              conditions of SSCs against licensee established goals, in a manner sufficient to provide
              reasonable assurance that such SSCs, as defined in paragraph (b), are capable of -
            . fulfilling their intended functions. Such goals shall be established commensurate with
              safety and where practical, take into account industry-wide operating experience. When
              the performance or condition of a SSC does not meet established goals, appropriate
              . corrective actions shall be taken." The inspectors reviewed the recent performance of      !
              the above systems and found that there had been six probabilistic safety assessment          i
              functional failures in Unit 1's 480Vac load centers and three probabilistic safety
              assessment functional failures in Unit 2's 480Vac load centers in the most recent 18
              ' months. However, since the licensee had not established probabilistic safety
              assessment functional failure performance criteria for these systems, the licensee had -    j
                not evaluated these systems for Category (a)(1) nor established system performance
                goals and taken appropriate corrective action as required by the Maintenance Rule. As      i
                a result of this observation, the licensee initiated corrective action and documented the
                problem in Condition Record 99-2925.
                                                                                                            ,
L.
 
n
  .
                                                    6-
    c.    Conclusiong                                                                                {
          The inspectors concluded that the licensee had adequately demonstrated that the
          postulated unavailability of nine systems did not significantly contribute to the overall
          core damage frequency. However, the inspectors identified inadequate reliability
          performance measures for eight plant risk-significant systems. As a result of the
          inadequate performance measures, the 480Vac load center system for both units was
          allowed to degrade beyond the probabilistic risk assessment assumed performance
          without the licensee having provided adequate technical justification for not having
          established goals, or appropriate corrective actions. This was a Severity Level IV
          violation of the Maintenance Rule and is being treated as a Non-Cited Violation,
          consistent with A.ppendix C of the NRC enforcement policy (EA 99-058). This violation
          is in the licensee's corrective action program as documented by Condition Record
          99-2925.
    M1.6 Goal Settina and Monitorina and Preventive Maintenance
    a.  Inspection Scope (62706)
          The inspectors reviewed program documents and records in order to evaluate the            ,
          process that was in place to establish performance measures for monitoring systems        !
          under Category (a)(1), or to verify that preventive maintenance was effective under
          Category (a)(2) of the Maintenance Rule.                                                  I
          The inspectors reviewed in detail the systems described below to verify: that goals or
          performance criteria were established with safety taken into consideration; that industry-
          wide operating experience was considered where practical; that appropriate monitoring
          and trending was being performed; and that corrective action was taken when a
          structure, system, or component function failed to meet its goal or performance criteria,
          or when a structure, system, or component function experienced a Maintenance Rule
          functional failure.
                  AM      Post Accident Monitoring (PAM)
                  BS      7300 Processor Support
                  DJ      125Vdc Class 1E
                  FW      Feedwater
                  HM      Mechanical Auxiliar/ Building HVAC
                  HZ      HVAC - Miscellaneous
                  MS      Main Steam
                  NI      Nuclear instrumentation
                  PC      13.8kVac Auxiliary Power
                  PE      480Vac Non-Class 1E Load Center
                  PK      4.16kVac Class 1E Power
                  PL      480Vac 1E Load Centers
                  PM      480Vac Class 1E MCC and Distribution Panels
                  RC      Reactor Coolant
                  RS      Reactor Control
L
 
      .
    .
                                                      -7-
                    SF      Engineered Safety Features Actuation
                    SG      Steam Generator Secondary Side
                    SP      Solid State Protection
                    VA      120Vac Class 1E Vital Power
<
                    XC      Containment Building
                    XS,    Switchyard System Auxiliary Feedwater
        b. Observations and Findinas
            As described in NUMARC 93-01, Revision 2, performance includes ". . . to the maximum
            extent possible both availability and reliability should be used since that provides the
            maximum assurance that performance is being maintained." The inspectors noted that
            under the terms of the Maintenance Rule, preventive maintenance must be
            demonstrated to be effective in controlling the performance or condition of a structure,
            system, or component such that the structure, system or component remains capable of    !
            performing its intended function.
            The inspectors acknowledged, as stated in NUMARC 93-01, instances where availability
            does not provide a meaningful measure of performance and should not be captured.
            Examples of accepted structures, systems, and components, such as reactor coolant
            system piping or electrical buses, were those which were not taken out-of-service for
            any routine testing or surveillance activities during power operations because of their
            absolute necessity for operation.
            The inspectors found that specific safety functions associated with the electrical loads
            were monitored by the corresponding system being supplied in lieu of monitoring the
            distribution system. For analogous mechanical systems, such as heating, ventilation,
            and air-conditioning systems, unavailability was appropriately monitored at the
            supported systems. During the inspectors' review of the facility's risk-significant
            structures, systems, and components without specific unavailability criteria, several
            systems were found to appropriately satisfy performance monitoring requirements for
            the associated structures, systems, and components, including mechanical auxiliary
            building heating ventilation air conditioning, miscellaneous heating ventilation air      l
            conditioning,13.8kVac auxiliary power,480Vac non-class 1E load centers,4.16kVac          l
            Class 1E power,480Vac Class 1E load centers,480Vac Class 1E motor-control centers
            and distribution panels, steam generator secondary side, containment building, and the
            switchyard system. Based on the system reviews, the inspectors deM; mined that these
            structures, systems, and components were being adequately monitored with appropriate
            plant level criteria and reliability performance measures.
            The inspectors observed that the steam generator power-operated relief valves, safety
            valves, and auxiliary feedwater steam supply were the only high safety-significant
            structures, systems, and components in the main steam system that provide standby
            functions. The licensee had established availability performance criteria for the steam
            generator power-operated relief valves and did not remove safety valves from service
            while online. The inspectors noted that should a safety valve need to be removed from
            service, performance would be adequately monitored by the plant level criteria. In
  .-
          _
 
,      . i
      .
                            4
    4
                                                        -8-
            - addition, the inspectors found that the availability of the auxiliary feedwater system
              .st eam suppl y was appropr  itla e y mon
                                                      it ored und er auxiliary f
                                                                              ee dwa er
                                                                                      t sys tem -
          -
            . performance criteria.
              The inspectors observed that the pressurizer power-operated relief valves and safety
              valves were the only high safety-significant components in the reactor coolant system
              that provide standby functions. The inspectors noted that online maintenance is not
              performed on the pressurizer power-operated relief valves and safety' valves. Licensee      {
              representatives considered removal of the power-operated relief valves from service as      l
          . a Maintenance Rule functional failure and would monitor this under the corresponding          l
              reactor coolant system reliability performance criteria. In addition, the inspectors noted  I
              that if power-operated relief valves were isolated for extended periods of time because
              of excessive seat leakage, as permitted by the licensee's technical specifications, that
              the licensee's staff considered the power-operated relief valves available. ,This was
              because only one action is needed to be performed by a dedicated operator to restore
              the valves to service for their risk-significant function (feed and bleed). The inspectors
          - found this monitoring approach acceptable.
              The inspectors observed that the licensee did not formally establish specific criteria
              associated with unavailability for risk significant systems, which were rendered
              unavailable for various routine maintenance testing and surveillance activities. The
            ' inspectors noted that the affected systems included post accident monitoring,7300 -
              processor support,125Vdc class 1E, main feedwater, main steam, nuclear
              instrumentation, reactor coolant, reactor control, engineered safety features actuation,
              solid state protection, and the 120Vac class 1E vital power system. The inspectors
              observed that online maintenance performed on these systems typically involved the
              removal or alteration of a normal automatic alignment, involving a channel or train for
              relatively short durations of time. Licensee representatives presented the basis for the
              program's adequacy as the application of plant level criteria to all risk-significant
              systems, and three conservative application points including: (1) loss of redundancy of      !'
              a scoped function is a Maintenance Rule functional failure even if the train or system
              function was not lost, (2) loss of a scoped function is a Maintenance Rule functional
              failure even if the function is not needed in the current plant mode, and (3) failures were
                                                                                                          i
              considered Maintenance Rule functional failures regardless of whether maintenance
              related activities were involved or associated with the failures.
            - The inspectors verified that all risk-significant structures, systems, and components        .
              (with those exceptions documented in Section M1.2) had Maintenance Rule functional          i
              failure criteria established, no repeat Maintenance Rule functional failures were          ;
            ^ permitted, and that probabilistic safety assessment functional failure criteria were
              established for those systems, which were modeled in the probabilistic safety
              assessment. Licensee representatives stated that all unplanned maintenance                  ,
              unavailability was captured as a Maintenance Rule functional failure even if the
                Maintenance Rule function had not been lost prior to taking it out-of-service, as
                referenced in the licensee's response letter to the NRC, NOC-AE-000132, dated
                April 14,1998.
  E
 
p
    /
  4
                                                        .g.
            In addition, the licensee management's expectation included that planned maintenance
            activities, su::h as routine testing and surveillances, which exceed planned allowed
            outage times for completion be characterized as Maintenance Rule functional failures.
            The inspectors noted that this was not a formally documented policy within the
            licensee's Maintenance Rule program, but found no examples where these conditions
            had not been captured as such. The inspectors were provided a copy of Condition            .
            Record 99-2894, which documented management's intention for capturing unavailability        l
            related functional failures and to make the necessary formal changes within their
            Maintenance Rule program procedures.
            The inspectors reviewed Licensee Event Report 98-004, Revision 00, and Condition
            Record 98 204565 for the solid state protection system and determined that adequate
            evaluations were performed in accordance with management's expectations and the
            requirements of the Maintenance Rule. The inspectors considered the capturing of
            maintenance performance activities as functional failures with unplanned or untimely
            activities as an indirect method of monitoring the associated unavailability of structures,
            systems, and components.
      c.    Conclusions
            The inspectors determined that the licensee's approach to monitoring risk-significant
            structures, systems, and components to be acceptable.
      M8    Miscellaneous Maintenance issues (92902)
      M8.1 (Closed) Violation 50-498:-499/9801-01: Failure to include the digital rod position
            indication and a control room heating ventilation air conditioning function within the
            Maintenance Rule program scope. The inspectors verified that the licensee's staff had
            placed the digital rod position indication system and the control room ventilation smo'ke
            purge actuation function in the scope of their Maintenance Rule program. In addition,
            the inspectors found that adequate historical review for the Maintenance Rule functional
            failures resulted in an appropriate classification in accordance with the Maintenance
            Rule.
      M8.2 (Closed) Unresolved item 50-498:-499/9801-03: Failure to adequately monitor the solid
            state protection system. The inspectors verified that the licensee's staff had establ!shed
            an indirect method of monitoring unavailability for risk-significant structures, systems,
            and components through capturing unplanned maintenance activities or planned routine
            maintenance (testing or surveillance) exceeding allowed outage times as Maintenance
            Rule functional failures. In addition, the inspectors noted that appropriate unavailability
            sensitivity studies for probabilistic safety assessment modeled structures, systems, and
            components showed minimal risk impact. The inspectors concluded that the licensee's
            actions were considered acceptable.
L        __
 
p
      '
i.                                                                                                          ,
  . *
I                                                        -10-
                                              V. Manacement Meetinas                                      I
        X1      Exit Meeting Summary
                                                                                                            i
        The inspectors discussed the progress of the inspection on a daily basis and presented the        l
        inspection results to members of licensee management at the conclusion of the inspection on        I
        February 25,1999. The licensee's management acknowledged the findings presented.                  i
        The inspectors asked the licensee staff and management whether any materials examined
        during the inspection should be considered proprietary. No proprietary information was          -
        identified.
        During the exit meeting on February 25,1999, the Manager, Systems Engineering, stated STP
        Nuclear Operating Company would include the requirement to count as a Maintenance Rule
        functional failure any instance where a high-risk system (or one of its trains) that does not have
        availability performance criteria is taken out-of service (not performing its risk-significant
        function) while at power for corrective maintenance, or any instance when its technical
        specification allowed outage time is exceeded, and that this will apply even if no Maintenance
        Rule function had been lost prior to taking the system out-of-service.
l
L
i-
I
w..
 
v
    .
                                                                                                      :
  9
                                                ATTACHMENT                                            j
                                      SUPPLEMENTAL INFORMATION
  '
                                  PARTIAL LIST OF PERSONS CONTACTED
      - Licensee
        P. Arrington, License Engineering
      W. Cottle, President and Chief Executive Officer
      R. Grantom, Administrator, Risk Management
      J. Groth, Vice President, Generation
      R. Harris, Manager, Reliability Engineering
      S. Head, Supervisor, License Engineering                                                        l
      J. Johnson, Manager, Engineering Quality                                                        ;
      T. Jordan, Manager, System Engineering
      A. Moldenhauer, Probabilistic Risk Assessment Engineer
      B. Mookhoek, License Engineering
      M. Murray, Supervisor, S stem Engineering
      T. Riccio, System Engir sering
      J. Sheppard, Vice Prec, dent and Special Assistant to the President
      T. Stroschein, Supervisor, Engineering
      J. Winters, Maintenance Rule Coordinator                                                        j
                                                                                                      i
      NBC                                                                                            ,
                                                                                                      !
      N. O'Keefe, Senior Resident inspector
                                      INSPECTION PROCEDURES USED
          IP 62706        Maintenance Rule
          IP 92902        Followup - Maintenance
                                ITEMS OPENED. CLOSED. AND DISCUSSED
          Opened
          50-498;-499/9904-01      NCV    Inspectors identified inadequate reliability performance
                                          measures for eight plant risk-significant systems. As a
                                          result of the inadequate performance measures, the
                                          480Vac load center system for both units was allowed to
                                          degrade beyond the probabilistic risk assessment assumed
                                          perforrnance without the licensee having provided
                                          adequate technical justification for not having established
                                          goals, or appropriate corrective actions.
 
n
    .
  1
                                                  -2-
        Closed
        50-498;-499/9904-01  NCV      inspectors identified inadequate reliability performance
                                      measures for eight plant risk-significant systems. As a
                                      result of the inadequate performance measures, the
                                      480Vac load center system for both units was allowed to
                                      degrade beyond the probabilistb risk assessment assumed
                                      performance without the licensee having provided
                                      adequa e technical justification for not having established
                                      goals, or appropriate corrective actions.                    4
                                                                                                  /
        50-498;-499/9801-01  NOV      Failure to include the digital rod position indication and a
                                      control room heating ventilation air conditioning function
                                      within the Maintenance Rule Program scope.
        50-498;-499/9801-03  URI      Failure to adequately monitor the solid state protection        1
                                      system.
                            PARTIAL LIST OF DOCUMENTS REVIEWED
      Condition Records:
      98-20456
      99 2743
      99 2908
      99-2916
      99 2925
      99-2984
      Licensee Correspondence:
                                  .
      NOC-AE-000132
      NOC-AE-000230
      Procedures:
      Procedure                Title                                                    Revision
      OPGP03-ZA-0090            Work Process Program                                    20
      OPGP03-ZX-0002            Condition Reporting Process                              17
      OPSP03-SP-0005R            SSPS Logic Train R Functional Test                      7
      OPSP03 SP-00088          . SSPS Train B Slave Relay Test (Outputs Blocked) 4
      OPSP03-SP-0006R            Train R Reactor Trip Breaker TADGT                      5
      OPGP04-ZE-0313 -          Maintenance Rule Program                                1
                                                                                                      4
      OPGP03-ZA-0091            Configuration Risk Management Program                  0
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