ML20246Q309

Application for Amends to Licenses NPF-11 & NPF-18,revising Tech Specs to Implement Generic Ltr 84-15 Diesel Generator Recommendations & Remove Footnotes No Longer Applicable

ML20246Q309
Person / Time
Site:	LaSalle
Issue date:	03/16/1989
From:	Morgan W COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20246Q315	List: ML20246Q309 ML20246Q325
References
5588K, GL-84-15, TAC-64991, NUDOCS 8903290013
Download: ML20246Q309 (7)

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• j/ ; ; /. Commonwealth One Fiat National Plart, Edison.

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Address Reply to: Post Office Box 767

• As[' Chicago, lilinois 60690 0767 N

March 16, 1989 U.S. Nuclear Regulatory Commission Attn Document Control Desk Washington, DC 20555 Subjects LaSalle County Station Units 1 and 2 Proposed Amendment to Implement Generic Letter 84-15 Diesel Generator Recommendations and Remove Footnotes Which No Longer Apply for Facility Operating Licenses NPF-ll and NPF-18 tiEC_ Rocket Nos. 50-373 and 50-374 References (a): J.H. Wilson letter to J.G. Dewease, " Issuance of Amendment No. 23 to Facility Operating License NPF Waterford Steam Electric Station, Unit 3 (TAC No. 64991)," dated September 28, 1988.

(b): C.W. Schroeder letter to H.R. Denton, Request for Exigent Change to NPF-11, Appendix A, Technical Specifications Regarding Diesel Generator Fast Starts, dated December 9, 1983.

Gentlemen Pursuant to 10 CFR 50.90, Commonwealth Edison proposes to amend Facility Operating Licenses NPF-11 and NPF-18, Appendix A, Technical Specifications. The purpose of this amendment is to revise the Technical Specifications to conform with the diesel generator test schedule recommendations given in NRC Generic Letter 84-15 and, additionally, remove footnotes which are no longer applicable to bring the Unit 1 Technical Specifications into conformance with the Unit 2 Technical Specifications.

Attachment A contains background information and justification for the proposed change. Attachment B contains the proposed changes to the Technical Specifications. The proposed Technical Specification changes have been reviewed and approved by both On-Site and Off-Site Review in accordance with Commonwealth Edison Company procedures. We have reviewed this amendment in accordance with 10 CFR 50.92(c) and determined that no significant hazards consideration exists. Our evaluation is documented in Attachment C.

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• US NRC March 16, 1989-l Commonwealth Edison is notifying the State of Illinois of our l- . appl i cat i on for thi s amendment by transmi tt i ng a copy of thi s letter and its attachments to the designated State Official.

Please direct any questions you may have regarding this matter to this office.

Very truly yours, I

W.'E. Morgan Nuclear Licensirig Administrator 1m Attachments As Background and Discussion B: Proposed Technical Specification Change

.C Evaluation of Significant Hazards Consideration cc: Regional Administrator - Region III Senior Resident Inspector .LaSalle Office of Nuclear racility Safety - IDNS P.C. Shemanski - NRR 5580k

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TECHNICAL SPECIFICATION CHANGE REQUEST

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.LASALLE COUNTY STATION UNITS 1-AND 2 BACKGROUND AND DISCUSSION

..AACKGEGIND 1

L LaSalle County lNuclearLStation is a two unit plant with five li emergency power diesel generators available to provide power to the engineered:

' safety feature (ESF) divisions. Each nuclear l unit has three.ESF' divisions

'which are provided with both normal.and emergency. power supplies. 1The emergency; power supplies are arranged as.follows:

Dix.Lglon 1 The ESF. Division.1 Bus on each unit is supplied emergency power by the "0" diesel generator which is' common to both units. The system is designed such that only.one unit-can be supplied emergency, power from "the "0" diesel generator at a time.

-Division 2 Emergency power for the ESF Division 2 Bus on each unit is supplied by

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" separate diesel . generators ("1A" and "2A" .for Units 1 and 2, respectively). The Division 2 EST Buses have a manual cross-connect capability between the two nuclear units, however, interlocks are provided which allow the diesel generators to supply only one bus at a time.

Diylg.on 3 1

The ESF Division 3 Bus on each unit is supplied emergency power l from a dedicated diesel generator ("1B".and "2B" for Units 1 and 2, respectively). There are no provisions for cross-connecting the Division 3 Buses between the units.

In Technical Specification 3.8.1.1 for each nuclear unit it is required that all three diesel generators on that unit, plus the Division 2 diesel generator lfrom the other unit, be maintained operable in Operational Conditions 1,-2 and

3. .For example diesel generators "0", "1A", "1B" and "2A" are required for

Unit 1 operation.

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4 The diesel generator (DG) test schedule contained in Table 4.8.1.1.2-1 of the Unit 1 and 2 Technical Specifications is computed on a per nuclear unit basis for the last 100 valid tests conducted on the diesel generators for one nuclear unit. With this type of schedule a few random failures to start on separate diesel generators can lead to an accelerated test schedule for at least four of the five station diesel generators and in some cases all five of the diesel generators. An accelerated test schedule for four or five diesel generators can be a severe drain on the plant operational resources. The required schedule, as it currently exists, is punitive in nature and has the potential for actually degrading the reliability of the diesel generators.

pISCUSSION The importance of diesel generator reliability was recognized in Unresolved Safety Issue A-44, " Station Blackout," and as part of the technical evaluation of this issue the NRC has issued Generic Letter 84-15, " Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability," which provided guidance for steps which could be taken to improve diesel generator reliability. This document provides an example of a proposed technical specification designed to help ensure diesel generator reliability without

' requiring an excessive amount of testing. The significant differences between the technical specification proposed by the NRC in the Generic Letter and the current LaSalle Station-specifications are as follows:

• The test frequency in the proposed technical specification is based on a per diesel generator basis as opposed to a pc' nuclear unit basis.

• The accelerated test schedule would go into affect if a diesel generator experiences two failures in the last twenty demands as opposed to the current technical specification which requiret.

an accelerated test schedule if there are two failures in the last one hundred demands on a nuclear unit.

The proposal in the Generic Letter clearly establishes an achievable reliability goal of 0.95 per demand for the diesel generators. Whenever a diesel generator experiences two or more valid failures in the last 20 demands, the maximum time between tests would be reduced from once per thirty one days to once per seven days. This test frequency would be maintained under the proposal until seven consecutive failure free demands have been performed and the nwmbe'r of f ailures, in the last twenty demands, has been reduced to one or less. Two failures in twenty demands is a failure rate of 0.1, or the threshold of acceptable diesel generator performance, and hence may be an early indication of degradation of the reliability of a diesel generator. However, when considered in the light of a long history of tests, two failures in the last twenty demands may only be a statistically probable distribution of two random events. Increasing the test frequency will allow for a more timely accumulation of additional test data upon which to base judgement of the reliability of the diesel generator.

A review of the technical specifications for several recently licensed plants was completed to determine the approach other utilities are taking to meet the recommendations of Generic Letter 84-15. Also reviewed was a recent mnendment (reference a) to the Waterford Steam Electric Station, Unit

.3, technical specifications. It was discovered that there are two basic approaches to compliance with the generic letter. Waterford Station included both Table 4.8.1 and Table 4.8.2 from the generic letter in their submittal while the other examples, of the recently licensed plants, only include Table  !

4.8.1. Upon careful review of the two approaches LaSalle Station has opted to follow the example of the recently licensed plants and has patterned this submittal after the Clinton Station Unit 1 technical specification. Clinton Unit 1 is a typical example of the recently licensed units and the LaSalle Station submittal has been patterned after the Clinton specification, for the following reasons:

• Table 4.8.1.1.2-1 in the Clinton technical specifications differs from Table 4.8.1 of the generic letter and is in fact more restrictive than the generic letter. The table in the generic letter only recommends tracking diesel generator failures in the last 20 valid tests, whereas, the Clinton specification tracks failures in both the last 20 and 100 starts. This approach helps to establish the reliability of each diesel generator on both'a short term and Icng term basis without requiring an excessive amount of testing.

• Table 4.8.2 of Generic Letter 84-15 contains a great deal of information which is inappropriate for inclusion in the technical specifications. The current philosophy of the nuclear industry and the NRC, as evidenced by the technical specifications for the recently licensed plants, is to limit the material included in the technical specifications to requirements necessary for safe operation of the plant. It would be more appropriate to place the recommendations contained in Table 4.8.2 of the generic letter in another document such as a regulatory guide.

• Instead of including Table 4.8.2 of the generic letter the Clinton specification refers, in Paragraph 4.8.1.1.3, to Regulatory Position C.3.b Regulatory Guide 1.108, Revision 1, August 1977. The regulatory position outlines reporting recommendations which are similar to those contained in the generic letter, although not as detailed.

• The threshold'for initiating a special report to the NRC under the requirements of Paragraph 4.8.1.1.3, of the Clinton specification, are in effect more restrictive than the thresholds given in Table 4.8.2 of the generic letter. The Clinton specification reporting requirements were written on a "per nuclear unit" basis as opposed to the "per diesel generator" basis in the generic letter. This approach allows early identification and correction of programmatic deficiencies which may arise.

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It is clear that the Clinton philosophy is a more balanced approach to establishment of a diesel generator a11 ability program than is the approach of the generic letter for the following reasons:

• The Clinton specification minimizes testing'of the diesel generators by basing the schedule on a "per diesel generator" basis.

• The Clinton specification allows early identification and' correction of programmatic deficiencies by basing the reporting requirements on a "per nuclear unit" basis.

• The Clinton specification is more easily interpreted and more concise.

It is proposed, by Commonwealth Edison, that the Unit 1 and 2 Technical Specifications be amended to replace the current requirements given in Table 4.8.1.1.2-1 with the proposed requirements given in Table 4.8.1 of Generic Letter 84-15. Refer to Attachment B for the specific changes.

I ADJ21IlOt!AL_ADtilNISTRATIVE CHAliGES The following administrative changes to the Unit 1 Technical Specifications are also being proposed to remove unnecessary footnotes and to correct an error (refer to Attachment B):

1. Remove the asterisk following the word " generators" in paragraph .

3.8.1.1 on page 3/4 8-1. Remove the footnote "*" at the bottom of I page 3/4 8-1 and delete page 3/4 8-la. These footnotes were added under Amendment No. 49 to allow Unit 1 operation, for a thirty day period, while the "2A" Diesel Generator was removed from service for addition of a pre-lubrication system. Since, the diesel generator modifications have been completed, these footnotes are no longer required and should be deleted.

2. Revise sentence one of Action Statement "f" of Technical Specification 3.8.1.1. to read: "With diesel generator 2A of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining A.C. sources by performing Surveillance Requirements 4.8.1.1.la. within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, and 4.6.1.1.2a.4., for diesel generator 1A, within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter; . . ." This snendment was originally requested in December of 1983 (reference b) as part of the amenchnent request to reduce the number of cold fast starts of the diesel

generators. The amount of-time allowed to start the diesel' generators, when one or more of the redundant power sources is found to be inoperable, was doubled in all of the. action statements to Technical Specifications 3.8.1.1. The purpose of this change was to allow for the longer period of time required to slow start and-warm the diesel generators prior to bringing them up to full speed. These changes were approved in Amendment 16 to the Unit 1. Technical Specifications (NPF-11) in March 1984.

On. January 13,.1984 an amendment request was submitted to the NRC to upgrade the Unit 1 Technical Specifications-to reflect the changes incorporated into the Unit 2 Technical Specifications at the time Unit 2 was licensed in December 1983. One of the changes included into this amendment. request involved a change to Action Statement "f" of Technical Specification 3.8.1.1. This snendment request was submitted prior to the time that Amendment 16 was approved, therefore, t!.e change would have been submitted with a copy of the then current page from the. technical specifications. As a result, while Amendment 16 extended the time period in Action Statement "f" for completion of Technical Specification 3.8.1.1. the subsequent snendment to this page (kaendment 18) restored the wording of the original. Pre-Amendment 16 page.

It is requested that the wording of the first sentence of Technical Specification 3.8.1.1. Action Statement "f" be restored to read as it did in Amendment 16 of the Unit 1 Technical Specifications. This will allow a more reasonable period of time for completion of the action requirements and it will make the Unit 1 Technical Specifications read the same as the Unit 2 Technical Specifications, thus-helping to avoid confusion on the part of the operators.

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