ML20076C321

ECCS Repts (F-47),TMI Action Plan Requirements,Beaver Valley Power Station Unit 1, Technical Evaluation Rept

ML20076C321
Person / Time
Site:	Beaver Valley
Issue date:	10/05/1982
From:	Ludington B, Overbeck G, Vosbury F FRANKLIN INSTITUTE
To:	Chow E NRC
Shared Package
ML20076C324	List: ML20076C321
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-C5506-267, NUDOCS 8210080265
Download: ML20076C321 (14)

Text

.

TECHNICAL EVALUATION REPORT ECCS REPORTS (F-47)

TMI ACTION PLAN-REQUIREMENTS DUQUESNE LIGHT COMPANY BEAVER VALLEY POWER STATION UNIT 1 NRC DOCKET NO. 50-334 FRC PROJECT C5506 FRC ASSIGNMENT 7 NRC CONTRACT NO. NRC43-81-130 FRC TASK 267 Prepared by F. W. Vosbury Franklin Research Center Author: G. J. Overbeck B. W. Ludington 20th and Race Streets Philadelphia, PA 19103 FRC Group Leader: G. J. Overbeck Prepared for Nuclear Regulatory Commission Lead NRC Engineer: E. Chow Washington, D.C. 20555 October 5, 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 implied, or assumes any legal liability or l

responsibility for any third party's use, or the results of such use, of any information, appa-I 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:

~  : cLi is _ kmk h Group f.edder

$f W principal Author D'e6artment D[ector(/

..___._..~..__Date /d-I-I Date. /04- U Date: /o - P & "2 4

XA Copy _Hos Been Sent to PDR . . Franklin Research Center A Division of The Franklin Institute The Benpmn Frankan Partmey, PMa., Pa. 19103 (215) 448 100o l

l cg*,oosou@p

\ mr e - - -

TER-C550 6-2ti7 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 with Those of Other Plants. . . . . . . . . 5 a 3.3 Review of Proposed Changes to Improve the Availability of ECC Equipment . . . . . . . . 7 4 CONCLUSIONS. . . . . . . . . . . . . . 9 5 REFERENCES . . . . . . . . . . . . . . 10 l

l t

l l

l I

l r

lii A .

b Franklin Research Center A w w w er-mi m i

4 TER-C5506-267 FORDf0RD This Technical Evaluation Report was prepared by Franklin Research Center under a contract with the U.S. Nuclear Regulatory Connaission (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.

e

+

~ ~ - . - .

TER-C5506-267

1. INTRODUCTION 1.1 PURPOSE OF REVIYA This technical evaluation report (TER) documents an independent review of the outages of the emergency core cooling (ECC) systems' at Duquesne Light Company's (DL) Beaver Valley ' Power Station Unit 1. The purpose of this evaluation is to determine if the Licensee has submitted a report tha.t is complete and satisfies the requirements of MI Action Item II.K.3.17, " Report on Outages of Duergency Core-Cooling Systems Licensee Report and Proposed (*

Technical Specification Changes."

1.2 GENERIC BACKGROUND Following the Three Mile Island Unit 2 accident, the Bulletins and Orders Task Force reviewed nuclear steam supply system (NSSS) vendors' small break loss-of-coolant accident (IDCA) analyses to ensure that an adequate basis existed for developing guidelines for sull 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 for which substantial outages might occur within the limits of the present technical specification. Therefore, to ensure that the small break IOCA analyses are consistent with the actual plant response, the Bulletin and Orders Task Force recommended in NUREG-0626 [1], " Generic Evaluation of Feedwater Transients and Small Break Ioss-of-Coolant Accidents in GE-Designed Operating Plants and

Near-Itra Operating License Applications," that licensees of General Electric (GE)-designed NSSSs do the following:

I l

" 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 f ailure or spurious isolation) . The outage data for ECC components should include all outages for the last five years of

_nklin Rese_ arch._. Center I

TER-C5506-267 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."

Later, the recommendation was incorporated into NUREG-0660 (2), "NRC Action Plan Developed as a Result of the MI-2 Accident," for all GE4esigned plants as mI Action Item II.'K.3.17. In NUREG-0737 (3), " Clarification of MI Action Plan Requirements," the NRC staff expanded this action item to include all PWRs 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 ae follows:

"The report should contain (1) outage dates and duration of outagest (2) cause of the outage; (3) ECC systems or components involved in the outage; and (4) corrective action taken."

1.3 PLANI-SPECIFIC BACKGROUND On December 31, 1980 (4), DL submitted a report in response to NUREG-0737, Item II.K.3.17, " Report on Outages of anergency Core-Cooling Systems Licensee Report and Proposed Technical Specification Changes." On August 2, 1982 [5] DL submitted a second report superceding the previous submittal (4] in response to a request for additional information by the NRC.

The second report submitted by DL covered the period from January 1,1976 through December 31, 1980 for Beaver Valley Unit 1. DL did not propose any changes for improving the availability of ECC equipment.

l d Franklin Research Center 4c .anasrh.r en===n

.m, , . _ _ . . - _ _ _ . . . - . - _ . . _ ._. . - - _ _ _ _ . . . . _ _ _ _ . . , . _ _ _ _ _ _ , , _ _ _ _ _ . _ . _ . _ _ , _ . . _ _ _ _ _ . _ _ . . _ _ _ , _ _ . _ _ . _ _ _ _

TER-C5506-267

2. REVIEW 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 [5]

outlining Tentative Work Assignment F. Provided as review criteria in Reference 5, 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 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 r Petts due to test and maintenance outages.

3. Proposed changes to improve the availability of ECC systems, if necessary.

The type of information required to satsLsfy 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 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.

b Franklin Research Center A w or n. Fr-.ma ===.

TER-C5506-267

3. TECHNICAL EVALUATION 3.1 REVIEW OF COMPLETENESS OF THE LICENSEE'S REPORT The ECC systems at DL's Beaver Valley Power Station consist of the following four separate systeas:

o safety injection system (SIS) o chemical volume and control system (CVCS) o accumulators o refueling water storage tank (RNST) .

In Reference 5, DL also included systems and components that support the ECC systems in carrying out their design functions under various accident conditions. The support systems are:

o reactor control and protection o river water sy, stem o emergency diesel generators o containment depressurization o supplemental leak collection and release.

Fbr each ECC system outage event, DL 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

- operational. The results of DL's review'were provided for the period from January 1, 1976 through December 31, 1980 for Beaver Valley Power Station Unit /1.

_, Based on the preceding discussion, it has been established that DL has submitted a report which fulfills the requirements of review criterion 1 without exception.

Ob Franklin Research Center A om.an or Tw. Fran an in nm.

TER-C5506-267 3.2 COMPARISON OF ECC SYSTDi OUTAGES WITH THOSE OF OTHER PURTS 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. The maximum allowable outage time, specified per event, tends to limit the unavai1^414ty 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 prelim-inary 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 I

operation during 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 j is operating at power. In addition, an ECC system was considered down whenever a.: 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 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 4 -s-db aFranklin cm a am. rr. ansaResearch m C. enter

- ..-,.,7-. -, . . , _ _ . _ , _ _ __ . - , , , , - _ _ _ .-,_m,. ,,,,,,y.s,-__-.-_,,,,,.-r+------++-w+--------*----t-----

TER-C5506-267 in each loop is required to satisfy core cooling recuirements, 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.

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 result. Such an analysis is beyond the intended scope of this report.

The planned and unplanned (forced) outage times for the four ECC systems (accumulators, SIS, CVCS, and RNST) and the emergency diesel generators were identified- from the outage,information-in Reference 5 and are shown in numb'ers of days and as percentages of plant operating time per year in Table 1 for Beaver Valley Unit 1. 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, "maclear Power Plant Operating Experience" (10-13], and from monthly reports, " Licensed Operating Reactors Status Summary Report" (14].

The remaining outages were segregated into planned and unplanned outages based

-on.DL'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 Beaver Valley Power Station 4

Unit 1 were compared with those of other IWRs. Based on this comparison, it was concluded that the historical unavailability of the accumulators, SIS, CVCS, and

- 1 . RNST-systems has been consistent with the performance of those systems throughout

-the. industry. The observed unavailability was less than the industrial mean for

.accumul ators, CVCS, and RNST and less than about one standard deviation above the industrial mean for the SIS assuming that the underlying unavailability is distributed lognormally. The outage times were also consistent with existing

_nklin Research._ _ Center

- - - , - - - - - - - - -- __ --.-,..-,-.--,,--.--,,--,.--,.--,.,,,,..------------w-,- -

---

.---.-----,..c ----ww i,,,-,.,--,-,,,,.v-,.,.,.,

TER-C5506-267 technical specifications. The outages of the emergency diesel generators were not included in this comparison.

3.3 REVIDt OF PROPOSED CHANGES TO IMPROVE THE AVAILABILITY OF ECC EQUIPMENT In Reference 5, DL did not propose any changes to improve the availability of ECC systems and components.

G I

M Franklin Research Center 4 % av The re w .

i , et . . . ,

1: . ,

! i .,. , ,

i e

N

$A3 IE no Table 1. Planned and Unplanned (Forced) Outage Times for Beaver Valley* Unit le g 33

,a >

g$ Accumulators CVCS SIS HWST Diesel Generator y Days of Plant Outage in Days Outage in Days Outage in hays Outage in Days Outage in Days n Year Operation Forced Planned Forced Planned Forced Planned Forced Planned Forced Planned

{S B

.d

$ 1976 222.7 0.04 0.0 0.0 0.13 0.30 0.29 0. 0 ' .'! O.0 0.0 8.25 (0.024) (0.068) (0.134) (0.134) (3.704) 1977 179.5 0.0 0.0 0.07 0.63 1.79 1.08 0.11 0.0 2.83 9.25 (0.044) (0.354) (1.000) (0.604) (0.064) (1.586) (5.154) 8 1978 148.7 0.01 0.0 0.64 0.25 3.42 1.42 0.0 0.0 0.63 12.46 -

l (0.01%) (0.434) (0.178) (2.306) (0.954) (0.426) (8.384) l 1979 146.0 0.0 0.0 0.06 0.17 0.50 0.83 0.0 0.0 0.0 7.13 l (0.044) (0.124) (0.346) (0.574) (4.884) 1980 31.5 0.0 0.0 . 0.0 0.04 0.26 0.13 0.0 0.0 0.0 10.98 i

(0.134) (0.834) (0.414) (34.866) i i

j Total '728.4 0.05 0.0 0.17 1.22 3.75 6.27 0.11 3.46 48.07

! (0.01%) (0.116) (0.174) (0.864) (0.516) (0.024) (0.486) (6.604)

H i .

5:

• Numbers in parentheses Indicate system outage time as a percentage of total plant operating time. b 4

m j sa

TER-C5506-267

4. CONCLUSIONS Duquesne Light Company (DL) has submitted a report for Beaver Valley Unit 1 that contains (1) outage dates and durations 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 DL has fulfilled the requirements of NUREG-0737, Item II.K.3.17. In addition, the historical unavailability of the accumulators, chemical and volume control, safety injection, and refueling water storage tank systems has been consistent with the perfor: nance of those systems throughout the industry. The observed unavailability was less than the industrial mean for the accumulators, chemical and volume control, and refueling water storage tank and less than about one standard deviation above the industrial mean for the safety injection system. 'me outage times were also consistent with existing technical specifications.

nk!!n Research Center

~ ~ -.-

TER-C5506-267

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 mI Action Plan Requirements" NRC, October 1980

4. C. N. Dunn (DL)

Intter to D. G. Eisenhut (Director, Division of I.icensing, NBC)

Subject:

Responses to NUREG-0737 December 31, 1980

5. J. J. Carey (DL)

Letter to Director of Nuclear Reactor Regulation (NRC)

Subject:

Response to NUREG-0737 Item II.K.3.17 RAI .

August 2,1982

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

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

Subject:

Contract No.

NRC-0 3-81-13 0, 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 l August 12, 1901

8. KRC Meeting between KRC and FRC.

Subject:

Resolution of Review Criteria and Scope of Work July 26, 1982 9 WASH-1400 t " Reactor Safety Study" NRC, October 1975

10. NUREG-0366 "Itaclear Power Plant Operating Experience 1976" NRC, December 1977

. _nklin Research._

_ .Center l

l l

TER-05506-267

11. NUREG-0483

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

12. NUREG-0618 "Welear Power Plant Operating Experience 1978" NRC, December 1979

13. NUREG/CR-1496

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

14. NUREG-0020

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

I Enklin

~~ Rese_ arch _ Center

. . . _ . . ___. - - _ . _ , _ _ _ _ _,._. _ _ _ , _ _ _ _ _ _ _ . , . _ _ _ . . _ _ ._ , _ . .