ML20141K351

Responds to Re Jg Martinez 851115 Questions Concerning 851107 Failure of Diesel Engine & Speed Control. Staff Recommended That Enhanced Maint & Surveillance Program Needed to Assure Reliability of Delaval Diesel Engines

ML20141K351
Person / Time
Site:	Grand Gulf
Issue date:	01/15/1986
From:	Stello V NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	Sarbanes P SENATE
Shared Package
ML20141K356	List: ML20141K351 ML20141K362
References
NUDOCS 8601220460
Download: ML20141K351 (6)

Text

.

', Y [* .

UNITED STATES 8" f NUCLEAR REGULATORY COMMISSION h

• WASHINGTON, D. C. 20555 e

t

\ .. . */

+

JAN 151986 The Honorable Paul S. Sarbanes United States Senate Washington, DC 20510

Dear Senator Sarbanes:

This is in response to your letter of November 25, 1985 regarding correspondence you received from Mr. John G. Martinez. His letter of November 15, 1985 raised several questions regarding the circumstances surrounding the failure on November 7,1985 of a diesel engine and speed controller (governor) at the Grand Gulf nuclear power plant. Mr. Martinez had inquired about the NRC response and more generally about past DeLaval diesel engine failures. The following information is provided in response to your inquiry.

During an engine test on November 6, 1985, immediately following an extensive preventive maintenance outage, one of the Delaval diesel engines at the Grand Gulf nuclear power plant underwent an engine overspeed event which caused physical damage to bearings and other critical components. The engine startup test being conducted at the time was intended to verify that the preventive maintenance operations just completed had been performed correctly.

Such a test is routinely performed after maintenance of this type is completed, but prior to placing the diesel engine into an operable status. During the recent maintenance outage considerable work had been perfonned on' the Woodward governor which required that the governor lube oil / hydraulic fluid be totally drained from the speed control unit. However, during refill of the governor lube oil system, the system was not properly vented and refilled.

During the preoperational engine startup test the governor, which is used to control engine speed (rpm), did not function because of the inadequate lube oil level and the engine accelerated to a speed well in excess of its design / operating speed. As a consequence, bearings, bushings, and other critical engine components were damaged. In addition to the governor speed control malfunction, the engine overspeed trip mechanism, which is designed to rapidly shutdown the engine during an overspeed event before the engine rpm reaches a damaging level, failed to trip the engine quickly enough to prevent engine damage.

Following this event the engine was disassembled and inspected by the utility.

The governor speed control unit was removed without repair and was shipped to the manufacturer, Woodward, for failure assessment and testing. Two NRC staff experts traveled to Grand Gulf on November 14, 1985 to inspect the damaged diesel engine and to evaluate the preliminary actions taken and/or planned by l the utility to repair the damage and prevent recurrence. On November 21, 1985 after the licensee, Woodward governor and Transamerica DeLaval, had completed their assessments, a senior staff member and a diesel engine consultant to the NRC met with the licensee and its representatives to complete the staff's review.

O de

f The NRC staff concluded that although DeLaval diesels had experienced problems in the past, this was the first engine failure arising from an overspeed

, event. The cause of the governor malfunction, which lead to the overspeed event and subsequent engine damage, was clearly identified as inadequate lube

, oil level and new procedures were developed to properly refill the governor after future maintenance operations. This information was promptly forwarded to owners of similar engines. Subsequent to the assessment of the overspeed i event, a potential design deficiency in the overspeed protection trip system was identified and a design modification was developed by Woodward and TDI to reduce the trip response time and enhance the required engine overspeed protection. The occurrence of an overspeed event, as experienced at Grand Gulf, was not considered to be a significant safety hazard because it occurred during post-maintenance testing which is routinely conducted prior to placing the engine into an operable status. The purpose for the tests being conducted  ;

at the time was to verify proper operation of the diesel and its control system before it was placed back into service. As such, the test served its intended purpose to identify a problem which could potentially shutdown an engine when it was called upon to provide backup power during an emergency situation. If the nuclear power plant had been operating when this event i,

(failure of a diesel engine) occurred, the emergency diesel generator system, which is a redundant system, would have provided adequate emergency power.

DeLaval diesel engines have been purchased for use by 13 nuclear utilities.

Several other diesel engine manufacturers have supplied engines to the remaining majority of the nuclear utilities for use as emergency on-site AC power supplies. Problems with DeLaval diesel engines were evaluated during the past

, two years subsequent to the crankshaft failure at the Shoreham Nuclear Plant.

t The staff has concluded that the problems experienced in the past with the DeLaval diesels were directly attributable to design, manufacture and quality assurance deficiencies which have been successfully addressed and resolved by the TDI Owners Group and its member utilities. The most significant staff recommendation coming from this study was that the implementation of an enhanced maintenance and surveillance program by each of the utilities was i

necessary to assure continued operability and reliability of these engines.

The test being conducted at Grand Gulf on November 7,1985 was being conducted l as part of that enhanced maintenance and surveillance program.

! If we can be of any further assistance, please contact 'us.

Sincerely, t

(Signerf) T. A, Rehm

Victor Stello, Jr.

Acting Executive Director for Operations

• SEE PREVIOUS SHEET FOR CONCURRENCE. )

l 0FC :RSB:PWR-A:BC:PWR-A:AD

PWR:D :NRp:DD :NRR:D

E00 { :0CA:pi

_____:__.g..______:___, __.___:____________:._Qf.

i NAME :CBerlin :JKnight* :H ompson :DEJyNihut :VStello 1

____:.__..__ger* :HD( on :CKammerer

{DATE:1/6/86 :1/7/86 :Id /86

_____:_..........:.___________:.___________:_.._________:_..h.____

1/}C/86

149/86 :1// 86 :1// $/86 0FFICIAL RECORD COPY /

, .:. 'c.-

DISTRIBUTION FOR EDO TICKET 001242 Central Files NRC PDR w/cy of incoming Local PDR w/cy of incoming ED0 #001242 ED0 Reading HDenton DEisenhut DCrutchfield Glainas TSpeis OELD l OCA l

SECY N JStello CKammerer PPAS (ED0 #001242) w/cy of incoming (4.sshoe HThorrpson PBaker LKitner Taylor GCunningham PD #001242 green ticket file JKnight CBerlinger

.( [

. . . e. .

\

x N

I hope that the information I have provided is satisfactory for your needs.

If we can be of any 'further assistance, please contact Dr. Carl Berlinger at (301)492-9794.

i Sincerely, N

N Victor J. Stello Acting Executive Director for Operations

\

\

6/8

0FC :RSB:PWR-A:BC:PWR-ArAD Y/ :PWR:D :NRR:DD :NRR:D :EDO :0CA:

NAME :CBerlinger :JKQght( :HThompson :DEisenhut :HDenton :VStello :CKammerer DATE :1/ s/86 :1/ 7/86 :1/ /86 :l/ /86 :1/ /86 :1/ /86 :1/ /86 0FFICIAL RECORD COPY

- _ _ _ _ _ - - _ _ _ _ - _ _ _ _ _ _ - _ - _ - _ - _ _ _ _ _ - - _ _ - _ _ _ _ _ _ - _ _ _ _ - _ - _ _ _ ~

r-

• j e

!' Q Ktt 'o, UNITED STATES 8 - ~t NUCLEAR REGULATORY COMMISSION d <f// ej)ff,

E WASHINGTON, D. C. 20555

/d /? 0 25

\..... -

EDO PRINCIPAL CORRESPONDENCE CONTROL

= - --

(.dus N EDO CONTROL: 001242 FROM: DUE: 12/26/85 DOC DT: 11/26/85 g

U M.p

• • pM SEN. PAUL S. SARBANES sgv j

& /s/ jzlgg TOs

![

a FINALREPLh

/

l CHAIRMAN PALLADINO FOR SIGNATURE OF: ** GREEN ** SECY NO: 85-1036

~

EXECUTIVE DIRkCTOR DESC: ROUTING:

ENCLOSES LETTER FROM JOHN G. MARTINE7 CONCERNING DFNTON INSPECTION OF FAILED COMPONENT PARTS AT GRAND GULF TAYLOR GCUNNINGHAM DATE: 12/11/85 AGOIONED TO: R4+-//[6 CONTACT: GRAGE- A

- - s.

SPECIAL INSTRUCTIONS OR REMARKS: ,

a NRR RECEIVED: 12/12/85 ACTION: DPL-A: THOMPSON ROUTING: DENTON/EISENHUT BURG - Q d L

S:n Paul'Sarban:s

-' CORRESPONDENCE CONTROL TICKET 2

SECY NUPSER: 85-1036 LOGGING DATE 12/6/85 0FFICE OF THE SECRETARY ACTION OFFICE: ED0 AUTHOR: -Sen Paul Sarbanes --Const Ref AFFILIATION: John G. Martinez 11/26/85 ID&R-5 MP&L LETTER DATE: FILE CODE n,.2na ni,1 r ADDRESSEE:

Palladino Concerns about failed component parts at the Grand Gulf 1 reactor

SUBJECT:

Direct Reply. . . Suspense: Dec 17 ACTION:

DISTRIBUTION:

OCA to Ack SPECIAL HANDLING:

NU"'

SIGNATURE DATE: FOR THE COP 9tISSION Champ Mec'd 0ff. EDO A.

.. ht . . . . .#.- //.;G. .,,

Time . . . . . .(. e. . . . . . . . .

EDO --- 0 01284 2