ML20204J692

Rev 5 to TVA Employee Concerns Special Program Rept 301.02-SQN, Diesel Generator Reliability Problems

ML20204J692
Person / Time
Site:	05000000, Sequoyah
Issue date:	03/16/1987
From:	Russell Gibbs, Murphy M, Russell J TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML082280289	List: ML20204J692 ML20204J721 ML20204J783 ML20204J839 ML20204J879 ML20204J936 ML20205A039 ML20205A089 ML20205A161 ML20205A301 ML20205A325 ML20205A368
References
1703T, 301.02-SQN, 301.02-SQN-R05, 301.02-SQN-R5, NUDOCS 8703270290
Download: ML20204J692 (18)

Text

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TVA EMPIAYEE CONCEkdS-REP 02T NUMBER:

301.02-bQN

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SPECIAL PROGRAN L

REPORT TYPE: Sequoyah Nuclear Plant Element Report REVISION NUMBER:

5 I'

TITLE: ' Diesel Generator Reliability Problems REASON FOR REVISION:

To incorporate TAS and SRP coments.

lR1 To incorporate SRP coments. CATD's, and SQN corrective action plan lR2 To incorporate SRP comments lR3 h

To incorporate SRP comments IR4 To incorporate clarification of conclusions

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l Subcategory: Mechanical Equipment Reliability / Design Element: Diesel Generator. Reliability Problems 4

I Report Number:

301.02-SQN R5

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Revision 5 I.

- DIESEL GENERATOR (D/G) RELIABILITY PROBLEMS f

I.

This element report evaluates the concern of reliability degradation of l

the emergency D/Gs which are part of the Onsite (Standby) Power System.

The concern is that too much testing, frequent starting and stopping, lack of preventive maintenance, and lack of upgrading combine to reduce the reliability and life of the emergency D/Gs.

The scope of this evaluation is limited to testing (qualification, preoperational, and surveillance), preventive maintenance, operation, and upgrading of the D/Gs.

The scope does not include design, loading, or load margin.

II.

SPECIFIC EVALUATION METHODOLOGY This element is made up of six concerns.

The following two concerns are generic:

"IN-85-323-001 - Continuous starting / stopping of Diesel Generators (due to testing) is detrimental to engine parts. Test program requires increased number of. tests after a certain number of failures. CI feels that increased frequency is contrary to vendor recommendations. CI could not provide specific test numbers. No additional information available. NUC Power concern. units 1 & 2."

"WI-85-100-003 - Diesel Generators have reliability problems. CI stated that correction requires reliability program, a reduction in the number of starts, attention to testing, preventive maintenance upgrading, and more interaction with INPO, other utilities and venoors to establish resolution to problems. CI has no further information. Anonymous concern VIA letter."

The following two concerns apply to other plants:

-XX-85-122-009, XX-85-122-010 are BFN and BLN concerns that are exactly the same as Concern XX-85-122-008 for SQN and the generic WI-85-100-003.

The remaining two concerns are specific to Sequoyah Nuclear Plant:

"XX-85-122-008 - Sequoyah: Diesel Generators have reliability problems. CI stated that correction requires reliability program, a reduction in the number of starts, attention to testing, preventative maintenance upgrading, and more interaction with INPO, other utilities and vendors to establish resolution to problems. CI has no further information. Anonymous concern VIA letter."

" MAS-85-001 - SQN - D/G AC lube oil pump tripped because of possible gnsket material in pump."

Page 1 of 16

Revision 5 The K-Forms were-reviewed to determine the areas of conce'en. The referenced documents were reviewed to determine the requirements. -The Diesel Generator Valid Start Log was reviewed to determine the historical reliability. Historical documents were reviewed to verify training of maintenance personnel and equipment upgrading. The Potential Reportable Occurrence Log and associated applicable Licensee Event Reports.(LERs) were reviewed to determine past problems and failures.

Interviews were held with three' cognizant individuals and walkdowns of the emergency D/Gs were conducted to determine the present conditions.

III.

FINDINGS The following areas were reviewed:

A.

Qualification of the Sequoyah Nuclear Plant (SQN) Emergency D/Gs During the licensing process for SQN, the NRC reviewed the D/G design and factory qualification tests. The NRC found that both the design and the qualification tests met regulatory requirements at the time.

This is documented in the SQN SER (NUREG 0011, reference 9).

Therefore the focus of this report is on maintenance and reliability issues which have surfaced since completion of the plant.

B.

Regulatory Requirements and Reliability The emergency D/G reliability requirements and frequency of " valid starts" is identified in the SQN Techn! cal Specifications in accordance with NRC Regulatory Guide 1.108 (references 28 and 7).

The present concerns center on reliability, maintenance, and overtesting. NRC has been concerned with D/G reliability for some time: " reliability of onsite emergency AC power sources has been a concern of both the commission and industry for at least a decade.

The issue of ' Diesel Generator Reliability' was identified as Generic Safety Issue B-56 in 1977. Since that time, several studies have been completed on diesel performance and reliability as well as on overall methods to improve reliability" (reference 5).

Initial reliability survey under NUREG-0471 (reference 6) cites industry-wide diesel reliability experience as 0.94 and more recently NUREG/CR-2989 cites reliability experience as 0.98.

The NRC reliability goal may be shifting from 0.99 as stated in NRC Regulatory Guide 1.108 to 0.95 proposed in Draft Regulatory Guide NUREG-1109, " Station Blackout", dated January 1986 (references 7 and 2).

A significant study conducted by the University of Dayton Research Institute involving LER reviews, literature searches, and interviews with licensees, inspectors, and vendors was published February 1979 as NUREG/CR-0660, " Enhancement of Onsite Emergency Diesel Generator Reliability", (reference 4).

The recommendations of this report applicable to SQN D/Gs (in the order of significance given in the report) are:

Page 2 of 16

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. Revision 5 1.

Effective' air dryers in the compressed air starting system are essential'to reliable operation.

2. ' Air quality'as regards accumulation of dust, dirt, and grit in the D/G room is essential to' reliable operation.

3.

A' continuing program of high quality training-for operations,'

maintenance, and supervisory personnel is required for reliable operation.

4.

Thoroughly test the D/G following maintenance and modifications.

5. _ Improvement of reliability hinges.on identification of " root cause" for problems and providing adequate corrective action.

6.

Paint concrete floors in the D/G room to minimize dust, dirt,-

and grit fouling problems with relays.

C 7.

Review other. reliability studies.

-8.

Establish a plan to implement NUREG/CR-0660 recommendations NRC requested information and comments from SQN personnel concerning NUREG/CR-0660. Among the recommendations of this NUREG is a warning concerning the operation of D/Gs at light or no load conditions

.(Reference 18). Additional information on light-load operation was discussed within TVA (reference 19). TVA's response to NRC was that light-load operation at SQN was minimized (reference 20). The only recommendation of the NRC letter left unanswered by TVA was the l

recommendation of dust control around D/G electrical equipment.

TVA's response to NRC questions describe training, maintenance, and other areas including dust control (Question 8.36) (reference 21).

NRC NUREG/CR-2989, " Reliability of Emergency AC Power Systems at Nuclear Plants," written by Oak Ridge National Laboratory and published July 1983, has the following recommendations to improve D/G reliability:

a.

Install air dryers on air start system compressors.

b.

Install dust seals on relays and relay cabinets.

c.

Have the governor periodically overhauled by the factory.

d.

Remove connections between independent diesel air start systems.

e.

Install water and sediment drains on fuel storage tanks.

Page 3 of 16 a

e

Revision 5 The conclusions of this report state that independent failure of D/Gs is an important contributor to the probability of an onsite AC power system failure, but significantly reducing the industry average probability of independent diesel failure will be difficult because there is no single subsystem that dominates the failure probabi.11ty. The report further states that common-cause failure probability may be reduced inexpensively by improving operating and maintenance procedures. The report suggests an extensive failure probability reduction factor is to add another D/G to the emergency onsite AC power system (reference 3).

In NUREG-0011, Supplement No. 2, (reference 9), NRC required that air dryers be installed in the air start systems, heavy duty turbocharger drive gear assemblies be installed on the engines, and formal training be given to maintenance and other related personnel. Operating air dryer assemblies for each D/G air start system were observed during inspections of the D/Gs by the evaluator. New heavy duty turbochargers were installed on DCRs (references 15 and 16).

Personnel training has been conducted on numerous occasions (reference 17).

In NUREG-0011, Supplement 2, the NRC staff states:

"Upon implementation of the above additions, modifications, and training, noted in the findings; the Sequoyah diesel generators, their auxiliary systems and their maintenance activities will also be in conformance with the recommendation of NUREG/CR-0660, ' Enhancement Of Diesel Generator Reliability' and the related NRC guidelines and criteria. We therefore conclude that this will provide reasonable assurance of diesel generator reliability through the design life of the plant."

TVA has reviewed and taken appropriate action in respons to information from NRC, Institute of Nuclear Power Operations (INPO), and other utilities, as well being willing to share information with these organizations (reference 27).

SQN Diesel Generator valid start history D/G starts are documented by Operations initially by OSLA7 and recently by SI-7.2 (references 10 and 11).

Inspection of these records yields the following reliability figures for SQN D/Go for the dates March 5, 1980 through August 13, 1986:

Diesel Number of Number Number Generator Starts Successful Failed Relicbility 1A-A 176 172 4

.9773 2A-A 152 148 4

.9737 IB-B 156 151 5

.9679 2B-B 154 153 1

.9935 l

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Page 4 of 16 L

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4 Revision 5' o:

As of August 13, 1986 the reliability data for.the last 100 starts on each Sequoyah D/G is:

Diesel Number of Number Number

. Generator Starts Successful Failed Reliability 1A-A 100 98 2

.980 2A-A 100 98 2

.980 IB-B 100 97 3

.970 2B-B 100 99 1

.990 These two sets of reliability data represent the reliability history of each Sequoyah emergency D/G tested based on " valid starts" as defined in NRC Regulatory Guide 1.108.

In response to NRC Generic Letter 84-15 (reference 1) TVA quoted D/G~

[

reliability as follows (reference 12):

Table 1

'SEQUOYAH D/G RELIABILITY MARCH 5, 1980 TO MAY IS, 1984 ij Total Number of Total Number of l

Unit Valid Tests Valid Failures Reliability 1 A-A 132 4

.969 2 A-A 128 2

.984 1 B-B 147 2

.986 2 B-B 132 0

1.000 Table 2 SEQUOYAH D/G RELIABILITY I

(last 100 starts)

Number of Number of Unit Valid Tests Valid Failures Reliability 1 A-A 100 3

.970 2 A-A 100 0

1.000 1 B-B 100 0

1.000 2 B-B 100 0

1.000 t

Page 5 of 16

's Revision 5 The SQN D/G Start. Log found in the unit control room indicates the following reliability data (reference 10):

Table 1 SEQUOYAH D/G RELIABILITY MARCH 5, 1980 to NAY 15, 1984 Total Number of Total Number of Unit Valid Tests Valid Failures Reliability-1 A-A.

132 3

.977 2 A-A 128 2

.984 1 B-B 147 2

.986 2 B-B 132 0

1.000 Table 2 SEQUOYAH D/G RELIABILITY (last 100 starts)

Number of Number of Unit Valid Tests Valid Failures Reliability 1 A-A 100 3

.970 2 A-A 100 1

.990 1 B-B 100 1

.990 2 B-B 100 0

1.000 These same discrepancies appear in two other documents that were reviewed (references 13 and 14).

Maintenance / Housekeeping During a waltdown of the D/Gs and Diesel Building completed by the evaluator, the following conditions contrary to NUREG/CR-0660 were observed:

Page 6 of 16

Revision 5 1.

Several lube oil leaks were found; " oil dry" compound had been used in most cases.

Some puddles of oil were observed. No work request tags were found for repair of these leaks.

I i

2.

Diesel fuel was found standing on top of every engine day tank.

Some tanks were observed to have more fuel oil on top, but in no case was the fuel oil judged to be over 1/4-inch deep.

3.

A general dusty and dirty condition was observed in each D/G room.

The dust was particularly heavy on top of the diesels.

4.

Numeroits work request tags were observed on the D/G and support equipment.

Examples are equipment not identified, bent tubing, and other damage.

5.

Piles of scrap pipe insulation and discarded cleaning rags were observed behind engine A of D/G 1 B-B.

6.

Dust was observed inside some electrical control cabinets.

7.

The D/G room floors are sealed but dusty and dirty.

8.

Temporary rags are wrapped around some of the air dryer purge drains.

9.

Several of the electrical control relays were observed to be either the open contact type or pneumatic time-delay type, both of which are susceptible to failures resulting from dust contamination.

No formal failure root cause analysis program separate from the LER evaluation procedure could be identified.

C.

Testing of the Emergency D/Cs Testing is an important part of the D/G reliability program.

NRC has identified the initial qualification testing program which was conducted at the manufacturing plant and included 305 start and load cycles to be satisfactory (reference 9).

The subsequent preoperational testing program which included 69 consecutive start and load cycles and a 24-hour full-load-carrying capability tect was found to be acceptable to both TVA design and NRC (references 24 and 22). The continuing surveillance testing program is accomplished by SQN operations personnel using Surveillance Instruction SI-7.2 (reference 11). The purpose of this SI is to document valid test starts of the emergency D/Gs as required by the SQN Technical Specifications and recommended by NRC Regulatory Guide 1.108 (references 28 and 7).

Page 7 of 16

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Revision 5 1 ", _

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'In September 1985. Electric Power Research Institute published EPRIi NP-4264, " Failures Related to Surveillance. Testing of Standby Equipment: Volume;2:. Diesel Generators". This;research was-started.

to investigate the belief.that surveillance testing for emergency D/Gs was reducing generator reliability..The results of this report stated that surveillance testing was'a factor.in many D/G failures; however, other factors su'ch as operation maintenance, and inadequacies of design contributed significantly and were not easy-

.to distinguish from the effects of surveillance testing. "Although.

maintenance was not responsible for many of these problems, the report identifies expansion of maintenance programs as the most

. promising way of: increasing overall reliability.~..".

In April 1986, Brookhaven National Laboratory published NUREG/CR-4557 ":to analyze the data and recommendations made by'the various groups associated with nuclear power diesel generators and to summarize the major recommendations of each group."

(reference 29). 'NUREG/CR-4557 presents'an overview-of.information and experience gathered on diesel generators as well as comments on NRC Generic Letter 84-15 which proposed a new D/G technical specification. Testing is a major issue in the report and the various parties involved generally agreed that overtesting can reduce the reliability and lifespan of the D/G sets. Unfortunately, the results are subjective and neither the utilities, regulators or vendors are able to produce hard data to support their position.

The NUREG tabulated utility responses to Generic Letter.on diesel generator reliability. The respondents generally were adverse to thr eequirements for increased surveillance following diesel failures.

Likewise, industry groups such as American Society of Mechanical Engineers (ASME), EPRI, INPO etc., stressed maintenance and analysis'over increased testing as a means to improve reliability.

A particular comment which appeared frequently was that fast, cold test starts should be limited or eliminated. Again, no hard data was presented to support degradation of reliability because of overtesting.

Finally D/G vendor responses were discussed. Although not all manufacturers participated, Morrison - Knudsen/GM, manufacturer of the SQN diesels, generally supported the others. Recommendations 2 included:

reduce fast starts, use prelube and prewarm (used at SQN), eliminate running unloaded (administratively in effect at SQN), and improve maintenance.

Of all the recommendations however, the fact remains that SQN Technical Specifications (Tech Specs) mandate periodic testing.

SQN sis prescribe testing to meet the Tech Specs and the tests are being run on schedule. Until the Tech Specs are revised, no significant change can be made to the test frequency or test methodology.

Page 8 of 16

Revision 5 o

D.

A search of all work requests from January 1,1982 through April 1986 failed to reveal any D/G lube oil pump failure due to gasket material. The SQN PRIME computer was used for document search.

==

Conclusions:==

Based on the findings in the various NUREGs and the EPRI report the industry's D/G's in general have reliability problems. Based on a review of the valid start data and the walkdown inspections it was concluded that the SQN D/Gs have reliability and cleanliness problems.

Independent of the data source referenced the lowest reliability factor noted was.9679.

More recent data indicate reliability improvements, although the reliability factors don't meet the current Reg Guide 1.108 goal of.99.

SQN appears to have the necessary level of management attention to further improve overall D/G reliability.

During inspections, the D/Gs were found to be very dirty, dusty, and plagued with various leaks. The general cleanliness condition could be greatly improved although it was recognized that this inspection was performed on a station that has been in a year long outage. Diesel Generator surveillance testing has continued during this outage on the frequency mandated in the technical specification (reference 11 and 28).

Overtesting, by industry consensus, may have a deleterious effect on D/G sets, but the views about this effect are controversial.

Unless relief is given by NCR, no change can be made to the test frequency. SQN management, by TS change 107, is incorporating items to resolve the test frequency issue.

See section VII of this report.

Based on the findings it is concluded that there are no outstanding safety related issues as explained in the following discussion:

Concern IN-85-323-001 is found to be valid because an increased number of I

surveillance starts following surveillance test failures is required lRS by the Technical Specifications. However, SQN D/Gs demonstrate I

reliabilities that are acceptable and are in line with the 0.98 1

industry average for availability.

I Concern WI-85-100-003 is found to be valid because of a lack of a formal reliability program, because of the combination of number of starts required by the Tech Specs and valid failures to start, and because of lack of preventive maintenance on the fuel and lube oil systems to eliminate leaks. The portion of the concern regarding internetico with INPO and other outside organizations was found to be not valid.

Concern XX-85-122-008 is found to be valid because improvement needed in reduction of the number of valid failures to start, because lack of establishment of a formal reliability program, because of the combination of number of starts required by the Tech Specs and valid failures to start, and because of lack of preventive maintenance on the fuel and lube oil systems to eliminate leaks.

The portion of the concern was found to be not valid regarding interaction with INPO and other outside organizations.

Page 9 of 16

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Revision 5 t

Concern NAS-85-001 could not be found valid, because of lack of findings on lube oil pump failure due to gasket saaterial.

p.

IV.

ROOT CAUSE

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Based on the findings, the root cause is determined to be two fold, lack of a formal DG trending analysis program and related follow-up and lack

'of adequate continuing housekeeping on the D/Gs.

V.

GENERIC APPLICABILITY Ba' sed on the findings, the reliability concerns are found to be generically applicable to all TVA nuclear plants. This issue will be investigated at all sites.

Concern MAS-85-001 related to a SQN specific issue and is not considered generic to other TVA sites.

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Revision 5-VI.

REFERENCES 1.

US NRC Generic Letter 84-15. " Proposed Staff Actions to Improve and.

' Maintain Diesel Generator Reliability," dated July 2, 1984, (A02 840716 019) 2.

USNRC NUREG-1109 (Draft Report for Comment), " Regulatory Analysis-for the Resolution of Unresolved Safety Issue A-44, Station Blackout," dated January 1986 3.

USNRC NUREG/CR-2989 (ORNL/TN-8545), " Reliability of Emergency A.C.

Power Systems at Nuclear Power Plants," dated July 1983 (A02 830810 005) 4.

USNRC NUREG/CR 0660-(UDR-TR-79-07), " Enhancement of On-site Emergency Diesel Generator Reliability," dated February 1979 (A02-790425 007) 5.

NUS Corporation, " Unresolved Safety Issues Review (February 1986 Update) Diesel Reliability (B-56)," dated February 1986 (No RIMS number assigned) 6.

USNRC NUREG-0471, " Generic Task Problem Descriptions, Category B, C, and D Tasks," dated June 1978 7.

USNRC Regulatory Guide 1.108, " Periodic Testing of Diesel Generator units Used as Onsite Electric Power Systems at Nuclear Power Plants" 8.

Electric Power Research Institute, " Failures Related to Surveillance Testing of Standby Equipment, Volume 2, Diesel Generators " EPRI NP-4264 dated September 1985 9.

USNRC NUREG-0011. " Safety Evaluation Report by the Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, in

.the Matter of Tennessee Valley Authority, Sequoyah Nuclear Plant units 1 and 2, Docket Number 50-327 and 50-328," dated March 1979, I

sections 8.3 and 9.6 10.

SQN Operations Instruc' tion OSLA7, "Sequoyah Nuclear Plant Operation Secton - Diesel Generator Log," dated August 10, 1982 -

Diesel Generator Logs for the Period March 5, 1980 to July 30, 1986 11.

SQN Surveillanco Instruction SI-7.2, " Diesel Generator Survoillance Frequency," revision 0, dated April 18, 1986 - Diesel Generator Start Logs for the period June 25, 1986 to August 13, 1986 i

Page 11 of 16

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Revision 5-

12. 1 Letter from L. M. Mills, Manager, Nuclear Licensing, to Harold R.

Denton.-Director-Office of Nuclear Reactor Regulation, U. S.

Nuclear Regulatory Commission, "In the Matter of the Tennessee Valley Authority Docket Nos. 50-259, 50-260, 50-296, 50-327, and 50-328," dated October 1, 1984 (L44 841001 807) 13.

Memorandum from T. G. Campbell, Site Director, NUC PR, Sequoyah Nuclear Plant, to L. M. Mills, "Sequoyah Nuclear Plant units 1 and-2.NRC Generic Letter 84 Proposed Staff Action to Improve and Maintain Diesel Generator Reliability,". dated October 4, 1984 (S01 841001 817) 14.

Letter from T. G. Campbell to L.M. Mills, "Sequoyah Nuclear Plant -

Proposed Technical Specification Change No. 107," dated August 15, 1984 (L53 840809 983--with attachment) 15.

SQ-DCR-945, (L24 810804 946) 16.

SQ-DCR-1203, (L53 820728 083) 17.

Various ccerespondence related to training for maintenance of DIGS.

RIMS Numbers:-

L24 810604 895 L28 810623 816 L24 810817 956 L47 810916 800 LO7 810923 802 L01 811218 801 L20 820107 801 L47 820128 801 L47 820303 804 L47 820311 806 L47 820319 802 L24 820325 896 L24 820426 931 L47 820907 802 L24 820325 897 L23 840417 922 18.

Letter from L. S. Rubenstein, Acting Chief Light Water Reactor Branch No. 4 Division of Project Management, NRC, to H. G. Parris, Manager of Power, " Implementation of the Recommendation of NUREG-0660, ' Enhancement of Onsite Emergency Diesel Generator Reliability' - Sequoyah Nuclear Plant, units 1 and 2 " dated January 17, 1980 (A02 800121 014) 19.

Memorandum from L. M. Mills to J. R. Calhoun, Director of Nuclear Power, "Sequoyah Nuclear Plant units 1 and 2 - Diesel Engine Driven Emergency Generator Operation at Light /No Load," dated February-20, 1980 (A27 800220 010)

Page 12 of 16

Revision 5 1

20.

Memorandum from J. R. Calhoun to L. M. Mills, "Sequoyah Nuclear Plant units 1 and 2 - Enhancement of Diesel Generator Reliability "

dated March 12, 1980 (L24 800306 845) 21.

Letter from-L. M. Mills to NRC, "In the Matter of the Application of Tennessee Valley Authority - Docket Nos. 50-327 and 50-328,"

dated May 19, 1980 (A27 800519 007) 22.

USNRC NUREG-0011, Supplement No.l.

23.

USNRC NUREG-0011, Supplement No.2.

24.

TVA SQN Preoperational Testing Program for the Emergency Diesel

~

Generators Unit 1:

DNE FINAL PREOP APPROVAL TEST DESCRIPTION DATE TVA-13A Onsite AC Distribution System 10/21/77 TVA-13B1 Onsite AC Distribution System 03/02/79

- Load Shedding Logic TVA-1382 Onsite AC Distribution System 03/21-79 TVA-13C Onsite AC Distribution System 12/15/79

- Diesel Generator Qualification TVA 13-D Onsite AC Distribution System 04/20/79

-Blackout TVA-14A Diesel Generator Fuel Oil 09/13/79 System TVA-14A R1 Diesel Generator Fuel Oil 05/04/79 System TVA-14B Diesel Generator Starting Air 03/08/78 System TVA-14C Diesel Generator Building 01/18/79 Heating and Ventilation System TVA-14D 125-V Diesel Generators 07/28/78 Battery System TVA-14D R1 Diesel Generators 125-V 04/16/79 Control and Field Flashing Batteries IVA-14E Diesel Generator Functional 09/26/79 Tests Page 13 of 16

Revision 5 Unit 2:

DNE FINAL PREOP APPROVAL q

TEST DESCRIPTION DATE TVA-1381 Onsite AC Distribution System 12/22/80

- Load Shedding Logic

-TVA-13B2 Onsite AC Distribution System 02/13/81 25.

SQN Surveillance Instruction SI-7, " Electrical Power System:

Diesel Generators," revision 35, dated July 7, 1986 26.

SQN Surveillance Instruction SI-7.1, " Diesel Generator AC Electrical Power Source Operability Verification (Diesel Generator /Offsite Source)," revision 7, dated July 14, 1986 27.

Various correspondence on D/G reliability.

RINs Numbers:

NEB 790509 355 EEB 821021 933 C69 790802 947 L23 821022 968 NEB 791004 105 L23 830105 880 L53 791011 948 L23 830127 914 A27 791029 010 A27 830325 007 L23 800311 849 L33 830329 808 L54 800417 800 A27 830607 010 NEB 800725 017 PWP 830616 518 L53 810324 972 L23 830829 918 L54 820614 620 L33 830916 809 L22 820823 801 L33 831109 805 SWP 820923 077 L33 831109 803 L22 831107 803 LOO 831116 305-LOO 831117 415 L33 840106 810 L23 840124 922 L23 840307 806 LO3 840315 406 L33 840703 802 L33 840917 802 L33 841004 801 S01 841001 817 L23 841026 909 L23 850108 973 Sol 850712 840 SS3 850722 989 L33 850729 801 L33 850624 804 L22 850828 801 L23 851004 849 L62 851023 681 Page 14 of 16

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Revision 5 28.. SQN Technical Specification, Section 3/4.8, " Electrical Power Systems, units 1 and 2"-

29.

USNRC NUREG/CR-4557 (BNL-NUREG-51969), "A Review of Issues Related to Improving Nuclear Power Plant Diesel Generator Reliability,"

dated Apell 1986 (A02 860509 015).

VII.

INNEDIATE OR IANG-TERN CORRECTIVE ACTION Corrective Action Tracking Document (CATD) 30102-SQN-02 documents Sequoyah's Corrective Action Plan (CAP) which states: "TS change 107 is incorporating items into the diesel generator start and test requirements that will resolve any diesel problems associated with testing. The Electrical Maintenance Section will evaluate the additional maintenance related items referenced in NUREG/CR0660 and NUREG/CR2989 to determine the need for inclusion into the present program. The CAP specified is considered an enhancement to the present system and will be completed by-June 6, 1987."

These actions are considered adequate and tracked by CATD 30102-SQN-02.

CATD 30102-SQN-01 was issued to SQN concerning the need for a strengthened housekeeping program for the DGs. Sequoyah's CAP in response to this matter states:

"Cleaniness of D/G control panels was considered as a potential contributor to D/G reliability. Consequently, the control panels for,

IA-A, 2A-A, IB-B and 28-B were thoroughly cleaned to remove accumulations of dust / grime. To maintain equipment in a clean condition. PMs have been prepared to perform annual and 18-month cleaning (see list below). The D/G building has also been included in a routine program for cleaning by maintenance laborers.

Building cleanliness has been significantly improved, and the routine cleaning will maintain it."

The Sequoyah CAP (CATD 30102-SQN-01) indicated the following PMs have been prepared:

18-Nonth NI-10.1E/1.5Y eleans the 480V Diesel Auxiliary Boards by using PMs 1485-82, 1484-82, 1483-82, and 1478-82.

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S' Revision 5 Annual MI-10.1E/A cleans 1) the Voltage Regulator Panel, 2) the Woodward Governor Panel 3) the Excitation Panel, 4) the Engine Control Panel,

5) the Engine Auxiliary Control Panel, 6) the Neutral Transformer Cubicle, and 7) the Generator Protective Relay Panel by using PNs 1482-82, 1480-82, 1479-82, and 1481-82.

NOTE: All PMs except 1484-82 for 2A-A D/G and 1478-82 for 28-B D/G have been completed. These will be completed by January 31, 1987.

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