ML20098G441

Forwards Response to Generic Ltr 84-15, Proposed Staff Actions to Improve & Maintain Diesel Generator Reliability

ML20098G441
Person / Time
Site:	Farley
Issue date:	09/28/1984
From:	Mcdonald R ALABAMA POWER CO.
To:	Varga S Office of Nuclear Reactor Regulation
References
GL-84-15, NUDOCS 8410050002
Download: ML20098G441 (8)

Text

r-Malling Address AltbIma Power Company 1'~

600 North 18th Street Post Office Box 2641 Birmingham, Alabama 35291 Telephone 205 783-6090 R. P. Mcdonald Senior Vice President Flintridge Building AlabamaPower resco"wnecurz systr' September 28, 1984 Docket Nos. 50-348 50-364 Director, Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.

20555 Attention:

Mr. S. A. Varga Joseph M. Farley Nuclear Plant - Units 1 and 2 Response to Generic Letter 84-15 Gentlemen:

Alabama Power Company has completed a review of Generic Letter 84-15, " Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability."

In accordance with Generic Letter 84-15, Alabama Power Company provides the attached information.

If there are any questions, please advise.

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R. P. Mcdonald RPM /CJS:grs-Tech Spec 11 SWORN TO AND SUBSCRIBED BEFORE ME

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Attachment Requested Information to Address Proposed Staff

' Actions to Improve and Maintain Diesel i

Generator Reliability

~ NRC Request

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I 1.

Reduction in'Ntsnber of Cold Fast Start Surveillance Tests for Diesel

' Generators This item is directed towards reducing.the number of ccid fast start surveillance tests for diesel generators which the staff has determined.

results _in premature diesel engine degradation. The details relating to

- this subject are provided in. Enclosure.1-(of. Generic. Letter 84-15).

Licensees are requested to describe their current programs to avoid cold ifast. start surveillance testing or their intended actions to reduce cold

' fast start surveillance testing for diesel generators.

APCo Response 1

Alabama Power Company has.been actively pursuing efforts necessary to improve onsite' diesel generator reliability for some time. The NRC has acknowledged this effort in' previous evaluations of technical specification change requests associated with the standby diesel generator system. This interest is exemplified by the formation of a special Alabama Power Company Diesel Generator Task Force-in 1981 to identify problem areas and to recommend corrective actions that enhance diesel generators reliability. The Task Force

. expressed'a concern that Technical Specifications required frequent testing of the remaining diesel generators if one diesel generator became inoperable. The Task Force recommended that the Technical Specification be optimized so as to

. eliminate excessive testing requirements. The Task Force report,'which also

- discusses diesel operation including starts, maintenance and design changes was transmitted to the.NRC by letter dated October'14,-1981. The concern that-particular types of testing and excessive testing of equipment required by the r

Technical Specifications may be adverse to safety was also identified as a concern by the NRC Task Group on Technical Specifications in their report, NUREG-1024,. dated November, 1983.

. In' Generic Letter 84-15,;the NRC staff emphasized that excessive testing of

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- the diesel generators, which entail cold fast starts, has a' negative impact on their overall reliability. Alabama Power Company was aware in 1981 that frequent cold fast starts subject the diesel engine to undue wear and stress.

Inithe interest of improving and maintaining the reliability of the standby

. diesel generators, Alabama Power > Company has worked closely with Colt Industries, the diesel manufacturer, and the NRC in.an effort to eliminate excessive testing and schedule requirements from the Farley Technical

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Specifications.

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^ Attachment-Requested :Infomation.to Address Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability

--Page 2=

Previously the Farley Technical Specifications contained a periodic testing schedule.which specified test intervals which varied in frequency from once every three. (3) days to once every 31 days in four steps. The appropriate test frequency was then -determined b.y the number of diesel generator start failures Lexperienced, on-a per plant basis. Alabama Power Company proposed, in accordance with the. diesel generator manufacturers recommendations, a periodic.

test schedule of two steps with test intervals of once every seven days and once

every fourteen days. The test frequency was dependent on the number,of test failures experienced, on a per diesel generator basis. Alabama Power Company also proposed a reduction in the ninber of diesel. generator starts which were required by.the-Action Statements of other Technical Specifications.

The above ' testing optimization. objectives were realized when the NRC issued

- Amendments 26 and 13 to the Unit 1 and Unit 2 Operating Licenses on March 1 and

. May 5,1982 respectively.

Alabama Power Company has followed Colt Industry's recomendation to prelubricate the diesel generator prior to test starts for some time prior to

- the issuance of Generic Letter-84-15, with the sole exception being the 18 month SI/LOSP tests. As ~ expressed by the NRC in the Generic Letter, routinely

. starting.the diesel generator without prelubricating the engine does constitute.

an improper and potentially detrimental test of the equipment.

The above actions were undertaken as a result of Alabama Power Company's concern for diesel -generator reliability.. it is believed that the actions taken to date' are consistent with the intent of the Generic Letter and thus, no

- further actions are necessary.

. NRC Request 2.

Dies'el Oc ;arator Reliability Data This item requests licensees to furnish the current reliability of each diesel generator r.t their plant (s), based on surveillance test data.

Licensees are requested to provide the information requested in Enclosure 2 (of Generic Letter.84-15).

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_ 1 Attachment Requested.Information.to Address Proposed Staff Actions

.to Improve-and Maintain Diesel Generator Reliability.

Page 3 APCo Response

.The. reliability of the diesel generators at the Farley Nuclear Plant has been determined in accordance with Regulatory Guide 1.108 position C.2.e as requested in Enclosure ~2 of Generic Letter 84-15 and is provided below. This

^ reliability;is based upon'the number of failures in the last 100 valid denends as requested in Enclosure 2 of. Generic Letter 84-15.

The number of failures in the last 20 and 100 valid demands, including

the time history of the failures is tabulated below:

Diesel Generator 4075 KW 2850 KW 1-2A 1B 2B 1C 2C

' Number of ' failures in the 1

0 0

1 0

last 20 valid starts (Failure dates in parenthesis)

(07-30-84)

(06-26-84)

Reliability value 95%

100%

100%

95%

100%

Number of failures in the 1

2.

2 2

0 last 100 valid starts (Failure dates-in parenthesis)

- (07-30-84)(12-21-82)(08-10-83)(12-04-82)

(04-12-83)(09-22-83)(06-26-84)

Reliability value 99%

98%

98%

98%

100%

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-(This. table ir.cludes data up to September 7,1984.)

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- Requested:Information to Address. Proposed Staff Actions to. Improve ~and Maintain Diesel Generator Reliability

. Page 4 APCo Response '(continued)'

t JAlabama Power Company does maintain a. record of diesel generator deman'ds

...'and failures A record of diesel generator starts and failures has been kept at FarleyL Nuclear Plant since'1981. Data associated with diesel generator starts l

and failures is collected to support surveillance scheduling. Although this data does not include all the provisions of Regulatory Guide 1.108 position C.3.a, it is the opinion of Alabama Power Company that the data collected is

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sufficient to adequately monitor the diesel's. reliability. This position was accepted by NRC Staff as a result of approval.of the aforementioned technical specification changes.

Infomation quite similar to the Regulatory Guide C.3.a provisions for-the Farley Nuclear Plant diesels was submitted to the NRC by_

letter dated December 7,1981 for the years 1977 through 1980.

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- Relative to the NRC question' concerning a yearly diesel data report, there

' urrently is not a formal reouirement to compress the yearly test, maintenance c

- and. operating data lfor each diesel generator into an annual reliability report.

By letter ' dated September 14, 1984, Alabama Power Company proposed that the

." Reportable Occurrence" requirement for each diesel generator failure (Technical

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~ Specification' 4.8.1.1.3) be replaced with a requirement that an annual diesel generator-reliability report for each diesel generator be submitted to the NRC (proposed Technical -Specification.6~.9.1.12). When this proposed technical specification change is approved by the NRC Staff, an annual report will_ be-compiled and submitted to the NRC.

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It is' noted that,' based'on-the' diesel generator reliability data submitted -

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. to:the NRC by-letter. dated. December 7,1981, and the data presented herein, the

. diesel Lgenerators at the Farley Nuclear Plant are more reliable under the urrent technical' specification testing requirements than was experienced under

- the previous provisions which required significantly more testing.

It is also.

recognized that a major contributor to the increased reliability of the diesel

' generators has been implementation of'other Diesel Generator Task Force recommendations..

. NRC Request 3.

Licensees are requested to describe.their program, if any, for obtaining

-.and maintaining a reliability goal. An example of a perfomance Technical 1

Specification to support a desired diesel generator reliability goal has

< been provided by the staff in Enclosure 3 (of Generic Letter 84-15).

Licensees are requested to comment on, and compare, their existing program or-any proposed program with the example performance specification.

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~ Attachment 1 Requested Information' to Address Proposed Staff Actions

'to Improve and Maintain Diesel Generator Reliability

'Page 5 t

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APCo Response

^1abamalPower Company has completed several activities in an effort to

. improve and maintain the overall reliability of the diesel generators. In 1981,

'the Diesel Generator Task Force addressed all corrective action recommendation items in NUREG/CR-0660, " Enhancement of On-Site Emergency Diesel Generator Reliability" as just recently requested in Enclosure 3 of Generic Letter 84-15, In -a~1etter to the Director of Nuclear Reactor Regulation dated October 14, 1981,LTask Force Report was transmitted to the NRC.. This report itemized each action' item and the actions taken or planned to enhance the reliability of the.

Farley. diesels. As a result of the Task Force actions, twenty-five design

changes and nine operational changes were recommended to enhance diesel generator. reliability.

.In addition to these ' activities, Ala' bama Power Company conducted an extended -review 'of the Farley Technical Specifications. Particular attention

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was given to the diesel generator surveillance testing requirements. As a result of this review, changes to the Farley Technical Specifications were.

proposed to enhance diesel generator reliability. The NRC's Standard Technical

Specifications,; at that time, recommen_ded the testing schedule provided in i

Regulatory Guide ;1.108 for routine periodic surveillance testing. This testing D,

schedule. relates the frequency of testing to the number of test failures experienced by 'all-the ' diesel generators at the facility.

The suggested test interva's varied from a frequency of once every three days to once every j

thirty-one days lin four steps.

Alabama Power Company and Colt Industries, the diesel manufacturer,-

. proposed a different test schedule with intervals of. fourteen and seven days.

The basis for the change in test ~ frequency was that a test frequency of 1

thirty-one days was too infrequent to provide reasonable assurance-of the diesel-generator's reliability; however, a testing frequency of three days on a routine t-ibasis would have an adverse effect.on the over-all reliability of the diesel

. generator to start and provide emergency power. to the safety-related loads.

' Alabama Power Company also proposed that the test schedule should not be such that failures experienced on a particular diesel ~ generator would have an adverse impact on the other diesel units due to increased testing.

It should be noted

that the NRC Task Group on Technical. Specifications, in NUREG-1024, dated November,1983, concluded that increased-testing of equipment on a redundant train.when a. failure is experienced on the other train does not represent an

improvement in overall plant safety. In fact, the increased surveillance

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testing has the potential for damaging the redundant system and placing the system or plant in a more vulnerable mode. Such surveillance stratagies can 4

degrade the needed system and increase ~ public risk.

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_ Requested Infonnationl to Address Proposed ' Staff Actions to' Improve and Maintain Diesel Generator Reliability -

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' Page-6.

.The. requested thcknica.1'. specification change was approved by Amendments 26

' and 13 to the Unit 1 and: Unit 2 Operating Licenses dated March 1 and May 5,1982

' respectively... The NRC conenented;in their evaluation of the requested Technical

.. Specification changes ~that the staff had long been interested in the s ptimization of the periodic testing schedule for diesel generators. The NRC o

' viewed the' requested changes to the. periodic testing schedule as a more refined

! optimization than the schedule then available in Regulatory Guide 1.108. The NRC-also agreed that there wereino safety or reliability. advantages achieved by

testing other diesel generators based.on the failures experienced by a 1particular. diesel generator unit.

Thef current ~ schedule for periodic : surveillance. testing of the diesel

. generators in the Farley -Technical Specifications is based upon relating the test frequency to the failure experienced on the particular diesel generator.

The' testing schedule varies from a seven-day to a fourteen-day test interval and the number of failures experienced on the specific diesel generator must be less

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than or equal. to two in the last 100 valid starts to maintain the 14 day test interval.

The Generic Letter also includes suggested operational changes and changes to the -Technical-Specifications for the purpose of enhancing diesel generator reliability. The proposed changes are modifications to the NRC's existing Standard Technical Specifications (STS). The NRC's STS are primarily structured for a single unit facility with two standby diesel-generators. When one diesel i generator.becomes inoperable, it.is implied that one of the two redundant W

safety-related-trains, necessary for safe shutdown and LOCA loads, becomes unavailable.- -Under these circunstances,' increased surveillance to verify the operability of the redundant diesel generator may be desirable.

At the Joseph M. Farley Nuclear Plant, a two-unit facility, the onsite s

emergency ac power supply consists of five diesel generators which supply standby power for 4160-Y emergency service buses F,.G, H, J, K and L of each

- unit. - These buses provide power to the emergency loads. The five diesel

. generators'are of two different sizes, as follows:

three 4075-kW diesel generators 1-2A,'1B and 2B, and two 2850-kW diesel generators 1C and 2C. Diesel generators 1-2A and 1C are assigned to the redundant load group Train A, while diesel generators 18,'2B, and 2C.are assigned to the redundant load group Train B.

Diesel generator 1B is uniquely assigned'to Unit 1, while diesel generator "2B is uniquely' assigned to Unit 2.

Diesel generators 1-2A 1C, and 2C are shared betweeen the two units,'but only diesel generator 2C can be connected to both

-units at'the same time.

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g Attachment Requested.Information to Address Proposed Staff Actions to Improve and_ Maintain Diesel Generator Reliability Page.7 Due to the unique five diesel generator design of the plo..c, rarley

emergency ac power system and its flexibility, it has been determined that the implementation of the staff's example Technical Specifications in the form which they appear would not be consistent with changes previously granted to the unit Technical Specifications by the NRC.- Furthermore, it has been concluded, following a review of the example Technical Specifications, that the suggested changes proposed _ in the Generic Letter have supported-the efforts already taken to modify the Farley Technical ' Specifications. -

As a result of the change already made in the Farley Nuclear Plant - Units 1 and 2 Technical Specifications, Alabama Power Company maintains that no

~ further alterations to the plant Technical Specifications are necessary.

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