ML20076C369

ECCS Repts (F-47):TMI Action Plan Requirements,Turkey Point,Units 3 & 4, Technical Evaluation Rept

ML20076C369
Person / Time
Site:	Turkey Point
Issue date:	11/29/1982
From:	Ludington B, Overbeck G, Vosbury F FRANKLIN INSTITUTE
To:	Chow F NRC
Shared Package
ML17345B242	List: ML20076C369
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-C5506-301-3, NUDOCS 8212010132
Download: ML20076C369 (16)

Text

TECHNICAL EVALUATION REPORT ECCS REPORTS (F-47) 7 TMI ACTION PLAN REQUIREMENTS

, FLORIDA POWER AND LIGHT COMPANY TIMKEY POINT UNITS 3 AND 14 l

NRC DOCKET NO. 50-250, 50-251 FRC PROJECT C5506 FRC ASSIGNMENT 7 NRC CONTRACT NO. NRC-03-81 130 FRC TASKS 301, 302 Prepared by F. W. Vosbury Frank!!n Research Center Author: G. J. Overbeck 20th and Race Streets B. W. Ludington Philadelphia, PA 19103 FRC Group Leader: G. J. Overbeck Prepared for Nuclear Regulatory Commission Lead NRC Engineer: E. Chow Washington, D.C. 20555 l

November 29, 1982 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 impiled, 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 intringe privately owned rights.

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Prepared by: Reviewed by: Approved by:

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• 4 Principal Autho'rJ Group ' Leader Department Director (Acting)

Date- ll~1Y U Date- N~#9~02 Date: " l'l2 2-4 XA Copy Has Been %ni to PDR Franklin Research Center A oivision er The Franklin institute The Benjarrun Franklin Parkway. PMa . Pa. 19103(215)448 1000 Ye <ga/2OIM N

TER-C5506-301/30 2 CONTENTS Section Title Page

( 1 INTRODUCTION . . . . . . . . . . . . . 1 1.1 Purpose of Review . . . . . . . . . . . 1 1.2 Generic Background. . . . . . . . . . . 1 1.3 Plant-Specific Background . . . . . . . . . 2 2 REVIEW CRITERIA. . . . . . . . . . . . . 3 3 TECHNICAL EVALUATION . . . . . . . . . . . 4 3.1 Review of Completeness of the Licensee's Report . . . 4 3.2 Comparison of ECC System Outages l with Those of Other Plants. . . . . . .! . . 5 I

3.3 Review of Proposed Changes to Improve tlyr Availability of ECC Equipment . . . . . . . . 10 4 CONCLUSIONS. . . . . . . . . . . .. . . 11 5 REFERENCES . . . . . . . . . . . . . . 12 l

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, FORENORD

- This Technical Evaluation Report was prepared by Franklin Research Center under a contract with the U.S. Nuclear Regulatory Cbasission (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 the NRC. )

Mr. G. J. Overbeck, F. W. Vosbury, and Mr. B. W. Ludington contributed to the technical preparation of this report through a subcontract with WESTEC ,

Services, Inc.  !

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1. INTRODUCTION 1.1 PURPOSE OF REVIEN This technical evaluation report (TER) documents an independent review of the outages of the emergency core cooling (ECC) systems at Florida Power and Light Company's (FPL) Turkey Point Units 3 and 4. The purpose of this evaluation is to determine if the Licensee has submitted a report that is complete and satisfies the requirements of TMI Action Item II.K.3.17, " Report on Outages of Emergency Core-Cooling Systems Licensee Report and Proposed Technical Specification Changes."

1.2 GENERIC BACKGROUND Tb11owing the Three Mile Island Unit 2 accident, the Bulletins and Orders Task Pbrce reviewed nuclear steam supply system (NSSS) vendors' small break loss-of-coolant accident (LOCA) analyses to ensure that an adequate basia 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 (HPCI) 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 HPCI system, but also about all ECC systems where substantial outages might occur within the limits of the present technical specification.

Therefore, to ensure that the small break LOCA analyses are consistent with I the actual plant response, the Bulletin and Orders Task Force recommended in l

l . NUREG-0626 [1] , " Generic Evaluation of Feedwater 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)-designed NSSSs do the following:

" Submit a report detailing outage dates and lengths of the outages for l all ECC systems. The report should also include the cause of the outage (e.g. , controller failure or spurious isolation) . The outage data for

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TER-C5506-301/302 ECC components should include all outages for the last five years of operation. The end result should be the quantification of historical unreliability due to test and maintenance outages. 'niis will establish if a need exists for cumulative outage requirements in technical specifications."

Later, the recomunendation was incorporated into NUREG-0660 [2], "NBC Action Plan Developed as a Result of the TMI-2 Accident," for GE-designed NSSSs as TMI Action Item II.K.3.17. In NUREG-0737 (3), " Clarification of 'IMI Action Plan Requirements," the NRC staff expanded the Action Icem 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 outage; (3)'ECC systems or components involved in the outage; and (4) corrective action taken."

1.3 PLANT-SPECIFIC BACKGROUND On January 2, 1981 [4] and March 2, 1981 [5], FPL submitted reports 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 reports submitted by FPL covered the period from January 1, 1976 to November 30, 1980 for the Turkey Point Units 3 and 4. FPL did not propose any changes to improve and control availability of ECC components or systems.

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2. REVIES CRITERIA The Licensee's response to NUREG-0737, Item II.K.3.17, was evaluated against criteria provided by the NRC in a letter dated July 21, 1981 [6]

outlining Tentative Work Assignment F. Provided as review criteria in Reference 6, the NRC stated that the Licensee's response should contain the following information:

1. A report detailing outage dates, causes of outages, and lengths of outages for all BCC 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 [7]. 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. Finclly, the "last five years of operation" was to be loosely interpreted as a continuous, 5-year period of recent operation.

On July 26, 1982 [8], the NRC further ::larified 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 NBC. 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.

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3. 'IECHNICAL EVALUATION 3.1 REVIEW OF COMP 2TEMSS OF THE LICENSEE'S REPORT The BCC systems at FPL's Turkey Point Units 3 and 4 consist of the following four separate systems:

o accumulators o safety injection system (SIS) l o residual heat removal (RHR) system l o refueling water stcrage tank (RWST) .

1 In References 4 and 5, FPL also included systems and components that support the ECC systems in carrying out their design functions under various accident conditions. We support systems are:

o standby diesel generators o component cooling water system o intake cooling water system.

In addition, FPL included the emer;ency containment filter system and the emergency containment cooling system. These systems are safety-related and are designed to mitigate the effects of a LOCA on the containment atmosphere; however, these systems are not required to prevent core damage and therefore are not considered to be ECC systems.

In establishing the type of events that constitute an ECC system outage, FPL considered 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, FPL 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. We results of FPL's review were provided for the period from January 1,1976 to November 30, 1980 for Turkey Point Units 3 and 4.

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.

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TER-C5506-301/302 3.2 COMPARISON OF ECC SYSTEM OUTAGES WITH THOSE OF CTRER PLANTS The outages of ECC systems can be categorised 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.

'The lanximum allowable outage time, specified per event, tends to limit the unavailability of an ECC system. However, there is no cumulative outage time limitation to prevent repeated planned and enplanned outages from accumulating extensive ECC system downtime.

Unavailability, as defined in general terms in WASH-1400 (9], is the probability of a system being in a failed state when required.' 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 during the last 5 years. To simplify the tabulation i 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 j small compared to the time it is operating at power. In addition, an ECC l

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 would be expected if the design capability of the system exceeded the capacity

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TER-C5506-301/302 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 require-ments, then an outage of a single pump would not prevent the system from per-forming 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 planned and unplanned outages of primary ECC system components. In accordance with the clarification 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 tends 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 i result. Such an analysis is beyond the intended scope of this report.

The planned and unplanned (forced) outage times for two of the ECC t

systems (RHR, RWST) and the standby diesel generators were identified from the

, outage information in References 4 and 5 and are shown in number of days and as a percentage of plant operating time per year in Tables 1 and 2 for Turkey Point Units 3 and 4. The accumulators are not listed in the tables as there were no outages reported [10]. The high-head safety inject: ion system is a shared system and is listed separately in Table 3. Outages that occurred during nonoperational periods were eliminated, as were those cacsed by failures or test and maintenance of support systems. Data on plant operating conditions were obtained from the annual reports, " Nuclear Power Plant Operating Experience" [11-14], and from monthly reports, " Licensed Operating Reactors Status Summary Report" [15]. The high-head safety injection system at Turkey Point Units 3 and 4 is a shared system in that four pumps are l

provided, any of which can supply either unit. The plant technical specifications require:

o four SIS pumps be operational for either plant to go critical; i o if one SIS pump is nonoperational for greater than 30 days, or if two SIS pumps are nonoperational for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, then both units must be shut down.

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TER-C5506-3 01/302 Table 1. Planned and Unplanned (Porced) Outage Times for Turkey Point Unit 3*

Days of Plant RER RNST DG Year Operation Outage in Days Outage in Days Outage in Days 1976 277.8 0.9 0.0 28.3 (0.3 % ) (10.2%)

1977 293.7 0.0 0.0 17.9 (6.1%)

1978 295.3 0.0 0.0 25.4 (8.6%)

1979 18B.0 0.0 0.03 18.1

(<0.1%) (9.7%)

1980 293.0 1.5 0.0 13.2 (0.5%) (4.5%)

'Ibtal 1347.8 2.3 0.03 10 2.9

, (0.2%) (<0.1% ) (7.6%)

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• Numbers in parentheses indicate system outage time as a percentage of total plant operating time.

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TER-C550 6-301/302 Table 2. Planned and Unplanned (Forced) Outage Times for Turkey Point Unit 4*

Days of Plant RHR WST DG Year Operation Outage in Days Outage in Days Outage in Days 1976 243.0 0.0 0.0 11.2 (4.6%)

1977 232.5 0.0 0.03 14.0

(<0.1%) (6.0%)

1978 279.0 0.0 0.0 24.3 (8.7%)

1979 265.2 0.0 0.0 18.4 (6.9%)

1980 257.7 0.0 0.0 13.9 (5.4%)

Total 1277.4 0.0 0.03 81.7 ,

(<0.1%) (6.4%)

• Numbers in parentheses indicate system outage time as a percentage of total plant operating time.

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'!ER-C5506-301/302 Table 3. Outage Times for 'Nrkey Point Units 3 and 4 Shared Safety Injection System Days System Required To Support Plant Year Power Operations Outage in Days 1976 335.4 2.3 (0.7%)

1977 349.5 4.7 (1.4 %)

1978 358.7 1.1 (0.3%)

1979 325.3 0.0 1980 356.8 1.0 (0.3%)

'Ibtal 1725.7 9.1 (0.5% )

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'IT R-C5506-301/302 Since the technical specifications allow a 304ay outage time for one SI pump, it was concluded that, for the comparison purposes in this review, the system was fully functional with only three SI pumps available. As a result the SI system outages caused by one SI pump being non-operational were removed

. from the data base. W e system outages are shown in number of days and as a percentage of the time the system was required to support either Unit 3 or 4 power operations. Se resulting SI system unavailability of 0.5% is less than the industry-wide mean for individual unit SI systems.

Observed outage times of various ECC systems at Turkey Point Units 3 and 4 were compared with those of other PWRs. Based on this comparision, it was concluded that the historical unavailability of the accumulators, SIS, RWST, and RER system has been consistent with the performance of those systems

.throughout the industry. .The observed unav=41=h41ity .was J. ass .than the industrial mean for all four ECC systems, assuming that the underlying unavailability is distributed lognormally. W e outage times were also consistent with existing technical specifications. W e outages of the standby diesel generators were not included in this comparison.

3.3 REVIEW OF PROPOSED CHANTS TO IMPROVE THE AVAILABILITY OF ECC EQUIPENT In Referetices 4 and 5, FPL did not propose any changes to improve the availability of ECC systems and components.

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4. CONCLUSIONS Florida Po.ter and Light Company (FPL) has submitted a report for Turkey Point Units 3 and 4 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 FPL has fulfilled the requirements of NUREG-0737, Item II.K.3.17. In addition, the historical unavailability of the accumulators, ItiST, SIS, and RER system has been consistent with the performance of those systems throughout the industry.

The observed unavailability was less than the industrial mean for all ECCS systems. The outage times were also consistent with existing technical specifications.

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5. . REFERENCES

1. NUREG-0626

" Generic Evaluation of Feedwater Transients and Small Break Ioss-of-Coolant Accidents in GE-Designed Operating Plants and Near-Term Operating License Applications" NRC, January 1980

2. NUREG-0660 "NRC Action Plan Developed as a Result of the MI-2 Accident" NRC, March 1980

3. NUREG-0737

" Clarification of ThI Action Plan Requirements" NRC, October 1980

4. R. E. Uhrig (FPL)

Letter to D. G. Eisenhut (Director, Division of Licensing, NRC)

Subject:

Submittal' of Information'1tequired by NUREG-0737 January 2, 1981

5. R. E. Uhrig (FPL)

Letter to D. G. Eisenhut (Director, Division of Licensing, NRC)

Subject:

Submittal of Information Required by NUREG-0737 March 2, 1981

6. J. N. Donohew, Jr. (NRC)

Letter to Dr. S. P. Carf agno (FRC) .

Subject:

Contract No.

NRC-0 3-81-13 0, hntative Assignment F July 21, 1981 l 7. NRC l Meeting between NBC and FRC.

Subject:

C5506 Tentative Work l Assignment F, Operating Reactor PORV and ECCS Outage Reports j August 12, 1981

8. NRC Meeting between NRC and FRC.

Subject:

Resolution of Review Criteria and Scope of Work July 26, 1982

9. WASH-1400

" Reactor Safety Study" NRC, October 1975

10. NRC Telephone Conversation between B. Ludington (FRC) and D. Mcdonald (NRC).

Subject:

Licensee ECCS Outage Submittal August 12, 1982 O

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11. NUREG-0366

" Nuclear Power Plant Operating Experience 1976" NRC, December 1977

12. NUREG-0483

" Nuclear Power Flant Operating Experience 1977" NRC, February 1979

13. NUREG-0618

" Nuclear Power Plant Operating Experience 1978" NRC, December 1979

14. NUREG/CR-1496

! " Nuclear Power Plant Operating Experience 1979" NRC, May 1981

15. NUREG-0020

" Licensed Operating Reactors Status Summary Report" Volume 4, Nos. 1 through 12, and volume 5, No. 1

'W3C, December 1980 through ~Januarf 1981

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