ML20076C326

ECCS Repts (F-47),TMI Action Plan Requirements,Fort Calhoun Station, Technical Evaluation Rept

ML20076C326
Person / Time
Site:	Fort Calhoun
Issue date:	10/05/1982
From:	Ludington B, Overbeck G, Vosbury F FRANKLIN INSTITUTE
To:	Chow E NRC
Shared Package
ML20076C328	List: ML20076C326
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-C5506-275, NUDOCS 8210080305
Download: ML20076C326 (14)

Text

TECHNICAL EVALUATION REPORT ECCS REPORTS (F-47)

TMI ACTION PLAN REQUIREMENTS OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION NRC OOCKET NO.- 50-285 FRC PROJECT C5506 FRC ASSIGNMENT 7 NRC CONTRACT NO. NRC-03-81-130 FRC TASK 275 Prepared by y, y, yo,yg7y Franklin Research Center Author: G. J. Overbeck 20th and Race Streets B. W. Ludington Philadelphia, PA 19103 FRC Group Leader: G. J. Overbeck Prepared for Nuclecr Regulatory Commission Lead NRC Engineer: E. Chow Washington, D.C. 20555 October 5, 1982 l

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 f 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.

Prepared by: Reviewed by: Approved by:

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Principal AIuthor / Group Leader tegartment Dfectod Date! /d/d F1 Date- # ~ #~N Date: /* # 1

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CONTENTS Section Title Page 1 IN15tODUCTION . .- . . . . . . . . . . . 1 1.1 Purpose of Review . . . . . . . . . . '. 1 1.2 Generic Background. ". . . . . . . . . . 1 1.3 Plant-Specific Background . . . . . . . . . 2 2 REVIBf CRITERIA. . . . . . . . . . . . . 3 3 TECHNICAL EVALUATION . . . . . . . . . . . 4 3.1 leaview of Cbepleteness of the Licensee's Report . . . 4 3.2 Comparison of ECC System Outages with Those of Other Plants . . . . . . . . . . 5 3.3 Review of Proposed Changes to Improve the Availability of ECC Equipment . . . . . . . . 8 4 COICLUSIONS. . . . . . . . . . . . . . 9 4

5 REFERENCES . . . . . . . . . . . . .' . 10 l

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TER-C5506-275 FOREWORD This Technical, Evaluation Report was prepared by Franklin Research Center under a contract with the U.S. Itaclear 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 the NRC.

Mr. G. J. Overbeck, Mr. 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 REVIBf h is technical evaluation report (TER) documents an independent review of l the outages of the emergency core cooling (ECC) systems at Omaha Public Power District's (OPPD) Fort Calhoun Station. Se purpose of th*is evaluation is to determine if the Licensee has submitted a report that is complete and satisfies the requirements of MI Action Item II.K.3.17, " Report on Outages of Baergency Core-Cooling Systems Licensee Report and Propoced Technical Specification Changes."

1.2 GENERIC BACKGROUND Fbliowing the Three Mile Island Unit 2 accident, the Bulletins and Orders Task Pbece reviewed nuclear steam supply system (NSSS) vendors' small break loss-of-coolant accident (IOCA) analyses to ensure that an adequate basis existed for developing guidelines for small break LOCA emergency procedures.

During these reviews, a concern developed abeaut the assumption of the worst single failure. Typically, the small break LOCA analysis for boiling water reactors (BNRs) 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. Bere is concern not only about the HPCI system, but also about all ECC systems for which substantial outages might occur within the limits of the present technical specification. Merefore, to ensure that the small break IDCA analyses are consistent with the actual plant response, the Lulletin and Orders Task Fccce recosmevied in NUREG-0626 [1], " Generic Evaluation of Feedwater Transients and Small Break Ioss-of-Coolant Accidents in GE-Designed Operating Plants and Near-Tern Operating License Applications," that licensees of General Electric (G3)-designed NSSSs do the following l

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

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TER-C5506-275 ECC components should include all outages for the last five years of operation. ite 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."

Later, the roccamendation was incorporated into NUREG-0660 [2], "NBC Action Plan Developed as a Result of the TMI-2 Accident," for all light water reactor plants as MI Action Item II.K.3.17. In NUREG-0737 [3], "Clarifica-tion of TMI Action Plan Requirements," the NRC staff added a requirerent 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 outager (3) ECC systems or components involved in the outager and (4) corrective action taken.'

l.3 PLANT-SPECIFIC , BACKGROUND On December 31,.1980 [4], OPPD submitted a report in response to*

NUREG-073 7, Item II.K.3.17, " Report on Outages of Baergency Core-Cooling Systems Licensee Report and Proposed Technical Specification Changes." The report submitted by OPPD covered the period from January 1,1976 to December 31, 1980 for Pcet Calhoun Station. On August 19, 1982 [5], OPPD submitted a second report in response to a request for additiona1'information concerning diesel generator and surveillance testing outages. The second report covered the same period described in the first report. OPPD did not include any recommendations in its reports to improve the availability of ECC system components.

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

outlining Tentative Work Assignment F. Provided as review criteria in i Reference 5, the NRC stated that the Licensee's rer;ponse should contain the following information: -

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1. A report detailing cutage 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 Pa * = due to tast and =mineanmace outages.

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3. Proposed changes to improve the availability of ECC systems, if 1 necessary. 2 The type of information required to satisfy the review criteria was J

clarified by the NRC on August 12, 1981 [7]. Auxiliary systems such as ,

component cooling water and plant soevice water systems were not to be considered in determinina the unavailability of ECC systems. Only the outages of the diesel generators were to be -included along with the primary ECC system 7

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 [8], 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. Se 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 '

I generator outage information within this review is not required.

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3. TECHNICAL EVALUATION .

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. 3.1 REVIDt OF CI:MPLET3 NESS OF THE LICENSEE'S REPORT i Se ECC systems at OPPD's 2' Ort Calhoun Station consist of the following four separate systems:

'o ' safety injection (SI) , tank o high pressure safety injection (HPSI) o low pressure safety injection (LPSI) o refueling water storage tank (PWST) .

In Reference 5, OPPD also included information on diesel generator

~* & ne ECC system outage data were extracted from the following plant records:

- ,o Licensee Event Reporta o maintenance orders o operation incidenc reports.

For each ECC system outage event, OPIC provided the outage dates, the 1

duration, and the cause, plus sufficient description to discern the corrective action taken. Maintenance and surveillance testing activities were included in the BCC system outage data, unless these activities were performed during a shutdown condition in which the affected ECC system was not required to be l operational. The results of OPPD's review were provided for the period from l

January 1, 1976 to December 31, 1990 for Port Calhoun Station.

Based on the peaceding discussion, it is concluded that OPPD has suba'tted a report which fulfills the requirements of review criterion 1 l withcut exception.

3.2 COMPARISON OF ECC SYSTDI OUTAGES WITH THDSE 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 4 dNU Franidin Reseerch Center A on .nh. rm -

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-w TER-C5506-275 preventive maintenance. Unplanned outages are reportable as Licensee Event Reports ,(LERs) under the technical specifications. Planned outages for periodic mainter.ance 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 purpcse of the technical specification maximum allowable outage times is to prevent extended plant operation = without sufficient ECC system protection.

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The maximum 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 unplanned outages from accumulating extensive EC system dcasst.ime.

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Unavailability, as defined in general ter:Us in WASH-1400 [9], is the probability of a system being in a failed state when required. However, for this review,.a detailed unavailability analysis v3s not required. Instead, a preliminary estimate of the unavailability of an ECC system was made by calcu-lating 'the ratio of the BCC system downtime ~to the number of days that the plant was in operation during the last 5 year s. - 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 syste.n was considered down whenever an ECC system component was unavailable due to any cause.

It should be noted that the ratio calcm W in this manner is not a true measure of the ECC system unavailabili'/y o t v* , outage events are included that appear to compromise system performance when, a 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 required for the system to fulfill its safety function. For example, if an ECC system consisting of cwo loops with. multiple pumps in each loop is desigr ad so that

' only one pump in each loop is required to satisfy core cooling requirec.ents, 4 bd Franklin Researen Center A % or n. r,.wan n

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TER-C5506-275 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. 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. Se 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 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, LPSI, and RNST) and the diesel generators were identified from the outage information in References 4 and 5 and are shown in number of days and as percentage of plat operating time per year in Table 1 for Fort Calhoun Station. Outages that occurred during nonoperational periods were eliminated as well as those caused 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" [10-13), and from monthly reports, " Licensed Operating Reactors Status Summary Reports" [14] . Se remaining outages were segregated into planned and unplanned outages based on an OPPD's description of the cauns. The outage periods for each category were calculated by susming the individual outage durations.

Observed outage times of various ECC systems at the Port Calhoun Station were compared with those of other PWRs. Based on this comparison, it was concluded that the historical unavailability of the SI tank, HPSI, LPSI, and RWST systems has been consistent with the performance of those systems throughout the industry. Se observed unavailability was less than the l

l industrial mean for all BCC systems, assuming that the underlying 1

unavailability is distrib:2ted lognormally. Se outage times were also dbbhranklin

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Is Table 1. Planned and Unplanned (Porced) Outage Times for Fort Calheen Station

• i i SI Tank HPSI LPSI sitW8T Diesel Generator

{n Outage in Days Outage in Days Outage in Days Outags in Days Outage in Days Days of Plant

[ Year Operation Forced Planned Forced Planned forced Planned Force 3 Planned Forced Planned

$ 254.4 0.0' O.0 0.0 3.5 0.0 0.6 0.05 0.0 0.04 0.4 1976 (1.45) (0.2%) (<0.1%) (0.018) (3.304) 0.0 0.0 0.1 0.0 0.0 0.0 0.0 21.0 1977 290.0 0.0 0.0

(<0.14) ,

(7.244)

I 3.1 0.0 8.5 0.0 0.0 0.0 17.4 Y 1978 274.3 0.0 0.0 0.0 (1.14) (0.2%) (6.344) 0.3 0.0 0.3 0.0 0.0 2.0 35.0 1979 349.3 0.0 0.0 0.0 (0.14) (0.14) (0.574) (10.254) 1.0 0.0 0.7 0.0 0.0 0.0 1.2 25.9 1980 224.0 0.0 0.0 (0. 4 %) (0.3t) (0.544) (11.564) 1.0 6.9 0.8 3.4 0.05 0.0 3.24 108.5 Total 1392.0 0.0 0.0

.(0.234) (7.794)

(0.14) (0.5%) (0.14) (0.14) (<0.14) ei

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

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, TER-C5506-275 consistent with existing technical specifications. The outages of the diesel generators were not included in this comperison.

3.3 REVIEN OF PROICSED CHANGES TO IMPROVE THE AVAILABILITY OF ECC EQUIPMENT In References 4 and 5, OPPD did not include any recommendations to -

- improve the availability of ECC systems and components.

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4. CONCLUSIONS Omaha Public Power District (OPPD) has submitted a report for Pbet Calhoun Station which 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 OPPD has fulfilled the requirements of NUREG-0737, Item II.K.3.17, and that changes to improve the availability of ECC systems are not required.

In addition, the historical unavailability of the safety injection tank, high pressure safety' injection, low pressure safety injection, and refueling water storage tank systems has been consistent with the performance of those systems throughout the industry.' The observed unavailability was less than the industrial mean for all ECS p. The outages were also consistent with existing technical specifications.

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5. REFERENCES

1. NUREG-0626

" Generic Evaluation of Feedwater Transients and Small Break

. T.oss-of-Coolant Accidents in GE-Designed Operating P13nts and Near-Tern Operating License Applications" NRC, January 1980 g .

2. NUR8G-0660 "NRC Action Plan Developed as a Result of the TMI-2 Accident" NRC, March 1980 .

3. NUREG-0737

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

4. W. C. Jones ;OPPD)

Letter to Director of Licensinry, D. G. Eisenhut

Subject:

Response to NUREG-0737 December 31, 1980

5. W. C. Jones (OPPD)

Letter to R. A. Clark (NRC) d

Subject:

Additional Informat, ion in Response to NUREG-0737 August 19, 1982

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

. Letter to Dr. S. P. Carfagno (FRC)

Subject:

Contract No. NRC-03-81-130, Tentative Assignment F July 21, 1981

7. NRC Meeting between NRC and FRC .

Subject:

C5506 Tentative Work Assignment F, Operating Reactor PORV and ECCS Outage Reports 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. NUREG-0366

"!Alclear Power Plant Operating Experience 1976" NRC, December 1977 4,d

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11. NUREG-0483 .

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

12. NUREG-0618

. "141 clear Power Plant Operating Experience 1978" NRC, December 1979

13. NUREG/CR-1496 "Itaclear Power Plant Operating Experience 1979" NRC, May 1981

14. NUREG-0020

" Licensed Operating Reactors Status Sunusary Report" Wlume 4, Nos.1 through 12, and Wlume 5, No.1 NBC, December 1980 through January 1981 O .

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