ML19332A447

Submits Info Re Status of Evaluation & Mods of Diesel Generator Annunciator Sys.Corrective Actions Required Include Separate Annunciator Sys for Disabling & Nondisabling Conditions & Wording on Annunciators

ML19332A447
Person / Time
Site:	Davis Besse
Issue date:	09/08/1980
From:	Victor R LAWRENCE LIVERMORE NATIONAL LABORATORY
To:	Shemanski P Office of Nuclear Reactor Regulation
References
RV-80-09-03, RV-80-9-3, NUDOCS 8009150526
Download: ML19332A447 (3)

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• LAWRENCE LIVERMORE LABORATORY.

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September 8, 1980 - RV 80-09-03

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Mr. Paul Shemanski, Operating Reactors Assessment Branch Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

DAVIS-BESSE NUCLEAR POWER STATION.- UNIT 1 Docket No. 50-346 DIESEL GENERATOR STATUS ANNUNCIATORS (TAC 07889)

REFERENCE:

1. NRC letter dated September 2, 1977 to Toledo Edison

2. Toledo Edison letter datea October 27, 1977 to NRC (John F.

Stolz from Lowel E. Roe)

3. NRC letter dated March 6,1979 to Toledo Edison, (James S.

Grant from Robert W. Reid)

4. Toledo Edison letter dated May 30, 1979 to NRC, (Robert W.

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Reid from Lowel E. Roe)

5. LLNL Report, UCID-18145,' " Status of Evaluation and Modifications' of Diesel Generator Status Annunciator Systems at Various U.S. Nuclear Power Plants," dated October 1979.

In their letter [Ref. 1], the NRC requested that the licensee (Toledo Edison)' provide information regarding the status annunciator system for the diesel

                                  . generators at their facility. This request for information was the result of reports from licensees on. incidents where diesel generators failed to respond to autotr. tic start signals because control switches or lockout and shutdown relays-were left in shutdown conditon by operators unaware of their status.

The principal reasons for this lack of awareness were.- (oO ,

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1. the sharing ofLannunciator systems for both disabling and non-disabling alarm conditions;

! 2. wording on annunciator windows for dis'aoling conditions which did not specifically-say that' diesel generator emergency start was blocked;.and

                             '3. disabling conditions which were not-annunciated in the            .

control room. The licensee' responded by letter'[Ref. 2] describing the diesel generator j annunciator system at Davis-Besse Nuclear Power Plant Station, Unit. l. - A review of the licensee's response by the NRC resulted in the NRC providing the licensee with the staff positions of diesel genertor lockout in its_ letter. dated March, 1979 (Ref. 3] which are:

1. All shared annunciators for disability conditions should not' be able-to be cleared until all abnormal conditions are corrected.

2. If a diesel generator is provided with a manual shutdown lockout relay, an alarm should be providea whicn is wor'ead to clearly indicate the diesel generator is incapable of an automatic start when the realy is not' set.

3. An alarm should be provided which clearly indicates when -the diesel generator control switch is not-in the automatic-position.

Additionally, the'NRC in its-letter [Ref. 3], requested that the licensee provide a statement that:

1. Your diesel generator system meets the staff positions,

2. will meet the staff positions, or i

3. provide'a justification for your' objection and submit and alternate solution to the concern......and i 1

4. provide ~a description of resulting proposed modifications.

The licensee responded.to the above~in its letter of May 30, 1979 [Ref. 4]. In this response the licensee states:

1. Davis-Besse Unit i emergency diesel-generator annunciators are in total I compliance to Position 1.  ;

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2. The annunciator window which alarms the condition that the safety shutdown lockout relay is not reset is presently inscribed; "Emer DG TRBL TRIP". We will reword this alarm to read: "EMERG DG LOCK-0UT OR TRBL TRIP". This will clearly indicate the diesel generator is incapable of an automatic start. The staticn's alarm procecures will also reflect this condition.

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3. The diesel generator voltage regulator control switch must be in the "0N" position for automatic operation. We propose to add a signal to the annunciator described in Position 2 response, given above, which will cause it to alarm when the voltage regulator control switch is off.

There is no control switch which removes-the auto-start capability of the diesel generator. To prevent a start of the diesel generator during maintenance,- the starting air supply and fuel supply are snut off by closing hand operated valves. These valves are shown in FSAR Figure Number 9-15A. This operation is strictly controlled by Plant Maintenance Procedure, AD 1844.00 and Safety Tagging Procs. dure AD 1803.00. In reviewing the above response, we believe that in oroer that the operator be provided with accurate, complete and timely information pertinent to the status of the diesel generators, as required by IEEE Std. 279-1971, the following corrective actions are required of the licensee. l- 1. Disabling and non-disabling conditions for each diesel generator should be separated and annunciated using separate annunciator systems.

2. The wording on the annunciators for disabling conditions should specifically state that the diesel generator is

unavailable for automatic start.

3. If the air supply and fuel supply are not alarmed when shut off, the diesel generator should be started after the maintenance has geen completed to insure its availability for automatic starting.

It is recommended that the licensee be informed fo the above requirements and l that corrective action be implemented. [iSpecialIssus'lrogr5' d V IC*

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R H l P Nuclear Systems Safety Program RAV:el l Copy to: M.H. Dittmore R. Epps

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