ML17301A001
| ML17301A001 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 09/28/1982 |
| From: | Ludington B, Overbeck G, Vosbury F FRANKLIN INSTITUTE |
| To: | Chow E NRC |
| Shared Package | |
| ML17214A397 | List: |
| References | |
| CON-NRC-03-81-130, CON-NRC-3-81-130, RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.17, TASK-TM TER-C5506-296, NUDOCS 8210010343 | |
| Download: ML17301A001 (14) | |
Text
TECHNICAL EVALUATION REPORT EGGS REPORTS (F-47)TMI ACTION PLAN REQUIREMENTS FLORIDA POMER AND LIGHT CONPANY ST LUCIE UNIT 1 NRC OOCKET NO.50-335 NRC CONTRACT NO.NRC43%1-130 FRC PROJECT C59$FRC ASSIGNMENT7 FRC TASK 296 Prepered by Franklin Research Center 20th and Race Streets Philadelphia, PA 19103 Prepered for Nuclear Regulatory Commission Washington, D.C.20555 Z.W-Vosbury Author'~J.Overbeck B.W.Ludington FRCGroup Leader: G.J.Overbeck Lead NRC Engineer: E.Chow September 28, 1982 XA Copy Has Been Senf foPDR This report was prepared as an account of work sponsored by an agency of the United States Government.
Neither the United States Government nor any agency thereof.or any of their employees, makes any warranty, expressed or Implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any Information, appa-ratus, product or process disclosed In this.report, or represents that Its use by such third party would not Infringe privately owned rights.Reviewed by: Approved by: Principal Aut Date: Group Leader D.te: Department Dlrec r Date: O Franklin Research center A Division of The Franklin institute We Senlarnin FranMln Parkway, Phile., Pa.19103 (215)448 1000 TERM550 6-29 6 Section Title Parcae 1 INTRODUCTION 1.1 Purpose of Review.l.2 Genetic Background.
1.3 Plant-Specific
Background
.2 REVLEW CRITERIA 3 TECHNICAL EVALUATION 1 1~2~3 3.1 Review of Completeness of the Licensee's Report 3.2 Comparison of ECC System Outages with Those of Other Plants.3.3 Review of Proposed Changes to Improve the Availability of ECC Zguipment.CONCLUS IONS~~~~~~~~~4 5 8~9 REPERENCES
~e~~~e~~~10 (ill Franklin Resenreh Center A Dlvbke d The F ra@On kaatute TER-C5506 296 This Technical Evaluation Report was prepared by Franklin Research Center under a contract with the U.S.Nuclear Regulatory Commission (Office of Nuclear Reactor Regulation, Division of Operating Reactors)for technical assistance in support of NRC operating reactor licensing actions.The technical evaluation was conducted in accordance with criteria established by I the NRC.-Mr-Q.J Overheck,-Mr Z..N Vosbury., and Mr B W Ludington contributed to the technical preparation of this report through a subcontract with WESTEC Services, Inc.Ijtl Franklin Research Center A GMsion d%he F tanldtn Institute TERW5506-296 lo INTRODUCTION 1+1 PURPOSE OP REVIEW This technical evaluation report (TER)documents an independent review of the outages of the emergency core cooling (ECC)systems at Plorida Power and Light Company's (PPL)St.Lucie Unit 1.The purpose of this evaluation is to determine if the Licensee has submitted a report that is complete and satisfies the requirements of TNZ Action Item ZZ.K.3.17,"Report on Outages of Emergency Core-Cooling Systems Licensee Report and Proposed Technical Specification Changes." 1 o 2 GENERIC BACKGROUND Following the Three Mile Zsland Unit 2 accident, the Bulletins and Orders Task Force reviewed nuclear steam supply system (NSSS)vendors'mall break loss-of-coolant accident (LOCA)analyses to ensure that an adequate basis existed for developing guidelines for small break LOCA emergency procedures.
During these reviews, a concern developed about the assumption of the worst single failure.Typically, the small break LOCA analysis for boiling water reactors (BWRs)assumed a loss of the high pressure coolant injection (HPCZ)system as the worst single failure.However, the technical specifications permitted plant operation for substantial periods with the HPCI system out of service with no limit on the accumulated outage time.There is concern not only about the HPCZ system, but also about all ECC systems for which substantial outages might occur within the limits of the present technical specification.
Therefore, to ensure that the small break LOCA analyses are consistent with the actual plant response, the Bulletin and Orders Task Porce recommended in NUREG-0626
[1]>"Generic Evaluation of Peedwater Transients and Small Break Loss-of-Coolant Accidents in GE-Designed Operating Plants and Near-Term Operating License Applications," that licensees of General Electric (GE)Mesigned NSSSs do the following: "Submit a report detailing outage dates and lengths of the outages for all ECC systems.The report should also include the cause of the outage (e.g., controller failure or spurious isolation)
.The outage data for ECC components should include all outages for the last five years of till!I Franklin Research Center h O&swn ol The Franldin Insotu>c TERM5506-296 operation.
The end result should be the quantification of historical unreliability due to test and maintenance outages.This will establish if a need exists for cumulative outage requirements in technical specifications.'ater the recommendation was incorporated into NUREG-0660
[2],"NRC Action Plan Developed as a Result of the TMI-2 Accident," for all GE-designed NSSSs as TNI Action Item II.K.3.17.
In NUREG-0737
[3],"Clarification of'INI Action Plan Requirements," the NRC staff expanded the action item to include all light water reactor plants and added a requirement that licensees propose changes that will improve and control availability of ECC systems and components.
In addition, the contents of the reports to be submitted by the licensees were further clarified as follows: "The report should contain (1)outage dates and duration of outages;(2)cause of the outageg (3)ECC systems or components involved in the outageg and (4)corrective action taken." 1 3 PLANT-SPECIPIC EACKGRDUND On January 2, 1981[4], PPL submitted a report in response to NUREG-0737, Item II.K.3.17,"Report on Outages of Emergency Core-Cooling Systems Licensee Report and Proposed Technical Specification Changes." The report submitted by PPL covered the period from March 1, 1976 to October 31, 1980 for the St.Lucie Unit 1.PPL did not propose any changes to improve or control ECC system availability.(ll!Franklin Research Center A Divelen B%he Frsnldln Instaute TERW550 6-29 6 2o REVIEW CRITERIA The Licensee's response to NUREG-0737'tem II.K.3~17, was evaluated against criteria provided by the NRC in a letter dated July 21, 1981[5],outlining Tentative Work Assignment P.Provided as review criteria in.Reference 5, the NRC stated that the Licensee's response should contain the following information:
l.A report detailing outage dates, causes of outages, and lengths of outages for all ECC systems for the last 5 years of operation.
This report was to include the ECC systems or components involved and corrective actions taken.Test and maintenance outages were to be included.2.A quantification of the historical unavailability of the ECC systems and components due to test and maintenance outages.3.Proposed changes to improve the availability of ECC systems, if necessary.
The type of information required to satisfy the review criteria was clarified by the NRC on August 12, 1981[6].Auxiliary systems such as component cooling water and plant service water systems were not to be considered in determining the unavailability of ECC'systems.
Only the outages of the diesel generators were to be included along with the primary ECC system outages.Finally, the"last five years of operation" was to be loosely interpreted as a continuous 5-year period of recent operation.
On July 26, 1982[7], the NRC further clarified that the purpose of the review was to identify those licensees that have experienced higher ECC system outages than other licensees with similar NSSSs.The need for improved reliability of diesel generators is under review by the NRC.A Diesel Generator Interim Reliability Program has been proposed to effect improved performance at operating plants As a consequence, a comparison of diesel generator outage information within this review is not required.~A IJ(l FranMin Research Center A Dlvhion of The Franklin Insome TER-C550 6-29 6 3 TECHNICAL E%iLUATION 3~1 REVZEN OF COMPLETENESS OP THE LICENSEE'S REPORT The ECC systems at PPL's St.Lucie Unit 1 consist of the following four separate systems: o.safety injection (SI)tank o high pressure safety injection (HPSZ)system o low pressure safety injection (LPSI)system o refueling water storage tank (RWST).In Reference 4, FPL also included systems and components that support the..ZCC.systems.hn.
carrying..out..their.
design..functions.under.various accideat conditions.
The support systems are: o containment spray o standby diesel generators o component cooling water o auxiliary feedwater system.In establishing the type of events that constitute an ECC system outage, FPL considexed an outage to be any event that rendered an ECC system unable to respond during plant conditions for which technical specifications required ECC system operability.
For each ECC system outage event, PPL provided the outage dates, the duration, and the cause, plus sufficient description to discern the corrective action taken.Maintenance and surveillance testing activities were included in the ECC system outage data, unless these activities were performed during a shutdown condition in which the affected ECC system was not required to be opex'ational.
The results of FPL's review were provided for the period from March 1, 1976 to October 31, 1980 for the St.Lucie Unit l.Based on the preceding discussion, it has been established that FPL has submitted a report which fulfills the requirements of review criterion 1 without exception.
t)ll Franklin Research Center A Oiwion ol The Frau4n lnseatc TERM550 6-29 6 3 2 COMPARISON OF ECC SYSTEM OUTAGES WITH THOSE OF OTHER PLANTS The outages of ECC systems can be categorized as (1)unplanned outages due to equipment failure or (2)planned outages due to surveillance testing or preventive maintenance.
Unplanned outages are reportable as Licensee Event Reports (LERs)under the technical specifications.
Planned outages for periodic maintenance and testing are not reportable as LERs.The technical specifications identify the type and quantity of ECC equipment required as well as the maximum allowable outage times.If an outage exceeds the maximum allowable time, then the plant operating mode is altered to a lower status consistent with the available ECC system components still operational.
The purpose of the technical specification maximum allowable outage times is to prevent extended plant operation without sufficient ECC system protection.
Themximum allowable outage Cime, specified~event, tends to limit the unavailability of an ECC system.However, there is no cumulative.outage time limitation to prevent repeated planned and unplanned outages from accumulating extensive ECC system downtime.Unavailability, as defined in general terms in WASH>>1400 (8], is the probability of a system being in a failed state when required.However, for this review, a detailed unavailability analysis was not required.Instead, a preliminary estimate of the unavailability of an ECC system was made by calculating the ratio of the ECC system downtime to the number of days that the plant was in operation duiing the last 5 years.To simplify the tabulation of operating time, only the period when the plant was in operational Mode 1 was considered.
This simplifying assumption is reasonable given that the period of time that a plant is starting up, shutting down, and cooling down is small compared to the time it is operating at power.In addition, an ECC system was considered down whenever an ECC system component was unavailable due to any cause.It should be noted that the ratio calculated in this manner is not a true measure of the ECC system unavailability, since outage events are included that appear to compromise system performance when, in fact, partial or full function of the system would be expected.Full function of an ECC system till Franklin Research Center A&vision oi~Franklin Insatute TERM5506-296 would be expected if the design'capability of the system exceeded the capacity required for the system to fulfill its safety function.For example, if an ECC system consisting of two loops with multiple pumps in each loop is designed so that only one pump in each loop is required to satisfy core cooling requirements, then an outage of a single pump would not prevent the" system from performing its safety function.In addition, the actual ECC system unavailability is a function of planned and unplanned outages of essential support systems as well as of planned and unplanned outages of primary ECC system components.
Zn accordance with the clarificat:ion discussed in Section 2, only the effects of outages associated with primary ECC system components and emergency diesel generators are considered in this review.The inclusion of all outage events assumed to be true ECC system outages tends to overestimate the unavailability, while the exclusion of support system outages t:ends to underestimate the unavailability, of ECC systems and components.
Only a detailed analysis of each ECC system for each plant could improve the confidence in the calculated result.Such an analysis is beyond the intended scope of this report.The planned and unplanned (forced)outage times for the four ECC systems (SI tank, HPSI, LPSZ, and RHST)and the standby diesel generators were identified from the outage information in Reference 4 and are shown in number of days and as percentage of plant operating time per year in Table 1 for the St.Lucie Unit l.Outages that occurred during nonoperational periods were eliminated as well as those caused.by failures or test an/maintenance of support systems.Data on plant operating conditions were obtained from the annual reports,"Nuclear Power Plant Operating Experience"[9-12], and from monthly reports,"Licensed Operating Reactors Status Summary Reports"[13].The remaining outages were segregated into planned and unplanned outages based on PPL's description of the causes The outage periods for each category were calculated by summing the individual outage durations.
Observed outage times of various ECC systems at St.Lucie Unit 1 were compared with those of other PHRs.Based on this comparison, it was concluded that the historical unavailability of the SZ tank, RWST, HPSZ, and LPSI systems has been consistent with the performance of those systems throughout 00 Franklin Research Center A Risen or The Frsnl4n Insatwe Table 1.Planned and Unplanned (Porced)Outage Times for St.Lucie Unit 1 SI Tank HPSI Outa e in Da s Forced Planned RWST Outa e in Da s LPSI Outa e in Da s Porced Planned Porced Planned Diesel Generator Forced Planned 1976 Commercial Oper.12/21/76 1977 309.2 0.0 0.0 0.04 1.46 (0.01%)(0'7%)0.0 lo71 0.0 (0'5%)0.0~6.02 1.83 (1.95%)(0.59%)1978 278.5 0.0 0.0 0.0 1 42 1.58 lo50 0.0 0.0 (0~51%)(0.571)(0~54%)0'5 1.71 (0.05%)(0'1%)1979 269.6 0.1 0.0 (0.04%)0.0 1.42 0.0 2o08 0 0 0.0 (0.53%)(0+77%)0.08 (0'3'0)l.5(0~56%)1980 288.2 0.0 0.0 0.0 1.42 1.92 i+50 0.0 0.0 (0'9%)(0.67l)(0'24)0.0 2,25~(0,78%)Total 1145.5 0.1 0.0 (0.01%)0.04 5.72 F 50 6'9 0.0 0.0 (<0.01%)(0.50%)
(0.3ll)=(0
'9%)-~.6,25 F 29 (0.55')(0.64%)*Humbers in parentheses indicate system outage time as a percentage of total plant operating time.
TERW5506-296 the industry.The observed unavailability was less than the industrial, mean for SZ tank, RWST, and HPSI systems and less than about one standard deviation above the industrial mean for the LPSI system, assuming that the underlying unavailability is distributed lognormally.
The outage times were also consistent with existing technical specif'ications.
3.3 REVIEW OP PROPOSED CHANGES TO IMPROVE'ITHE AVAILABILITY OP ECC EQUIPMENT'I In Reference 4, PPL did not propose any changes to improve the availability of ECC systems and components.
9I!Franklfn Research Center A 5vtsen d Iht frsnldn hsacute TERM550 6-29 6 4 CONCLUSIONS Plorida Power and Light Company (PPL)has submitted a report for St.Lucie Unit 1 that contains (1)outage dates and duration of outages, (2)causes of the outages, (3)ECC systems or components involved in the outages, and (4)corrective actions taken.It is concluded that PPL has fulfilled the requirements of NUREG-0737, Item IZ.K.3.17.
In addition, the historical unavailability of the SI tank, RWST, HPSI, and LPSI systems has been consistent with the performance of those systems throughout the industry.The observed unavailability was less than the industrial mean for the SZ tank, RWST, and HPSI'systems and less than about one standard deviation above the industrial mean for the LPSZ system.The outage times were also consistent with existing technical specifications.
tllI Franklin Research Center TERW550 6-29 6 5 REPERENCES NUREG-0626"Generic Evaluation of Peedwater Transients and Small Break Loss~f-Coolant Accidents in GE-Designed Operating Plants and Near-Term Operating License Applications" NRC, January 1980 24 NUREG-0660"NRC Action Plan Developed as a Result of the TMI-2 Accident" NRC, March 1980 30 NUREG-073 7"Clarification of TMI Action Plan Requirements" NRC, October 1980 4 R.E.Uhrig (PPL).Letter',~
D.Q Eisenhut.(Director, Division of Licensing NRC)Subjecti Submittal of Information Required by NUREG-0737 January 2, 1981 5.J.N.Donohew, Jr.(NRC)Letter to Dr.S.P.Carfagno (PRC).
Subject:
Contract No.NRC-03-81-130, Tentative Assignment P NRC, July 21, 1981 6o NRC Meeting between NRC and PRC.
Subject:
C5506 Tentative Work Assignment P, Operating Reactor PORV and ECCS Outage Reports'ugust 12, 1981 70 NRC Meeting between NRC and PRC.
Subject:
Resolution of Review Criteria and Scope of Work'uly 26, 1982 WASH-1400"Reactor Safety Study" NRC, October 1975 9.NUREG-0366"Nuclear Power Plant Operating'Experience 1976" NRC, December 1977 10.NUREG-048 3 Nuclear Power Plant Operating Experience 1977" NRC, Pebruary 1979 II'ranklin Research Center A Susen ot The FnusSn Ins~
TER-C5506-29 6 11 NUREG-0 618"Nuclear Power Plant Operating Experience 1978" NRC, December 1979 12 NUREG/CR-14 96"Nuclear Power Plant Operating Experience 1979" NRC, May 1981 13 NUREG-0020"Licensed Operating Reactors Status Summary Report" Volume 4, Nos.1 through 12, and Volume 5, No.1 NRC, December 1980 through January 1981 99 Franklin Research Center A&veen el The Frankfin Insotuct