ML20064C234

Forwards Proposed Tech Specs to Require Diesel Generator Start Time of Less than or Equal to 20

ML20064C234
Person / Time
Site:	Millstone
Issue date:	10/11/1978
From:	Counsil W NORTHEAST UTILITIES
To:	Reid R Office of Nuclear Reactor Regulation
References
TAC-46174, TAC-7317, TAC-7321, TAC-7420, TAC-7546, TAC-8169, TAC-8631, NUDOCS 7810170210
Download: ML20064C234 (12)

Text

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IMHtTHI!JWI' ITI'II.ITIIES 3 :1.5A . IT L~~ N0ro*nE CONNECTICUT 06t01

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October 11, 1978 Docket No. 50-336 .

Director of Nuclear Reactor Regulation Attn: Mr . R. Reid , Chief Operating Reactors Branch #4 -

U. S. Nuclear Regulatory Commission Washington, D. C. 20555

References:

(1) W. G. Counsil letter to R. Reid dated August 11, 1978.

(2) D. C. Switzer letter to G. Lear dated December 13, 1977.

(3) D. C. Switzer letter to R. Reid dated February 23, 1978.

Gentlemen:

Millstone Nuclear Power Statloc, Unit No. 2 Diesel Generator Start Times In Reference (1), at the request of the NRC Staff, Northeast Nuclear Energy Company (NNECO) proposed to modify Technical Specification 4.8.1.1.2.a.3 to require a diesel generator start time of less than or equal to 20 seconds. The appropriate-ness of the 20-second specification is discussed in References (2) and (3).

During the past several weeks, discussions with the NRC Staf f have identified the need for additional information to clarify the acceptability of the proposed interval; .the Staff has also requested additional peripheral information regarding diesel generator performance. Accordingly, the following information is provided.

It is emphasized that although 20 seconds is an acceptable interval from the perspective of fulfilling safety analysis assumptions and is, therefore, the appropriate value for Technical Specifications, diesel generator start times in excess of 12 seconds will be cause to initiate investigation and the appropriate corrective action will be taken. The diesel generators were designed to start within 12 seconds and this feature remains unchanged. Nonetheless, it is not appropriate to specify a start time less than 20 seconds because it is not re-quired by docketel safety analyses.

During recent discussions with the Staff, additional information was also requested regarding all equipment powered by the diesel generators under loss of offsite power conditions. Accordingly, Attachment 1 is provided and addresses the permanently connected loads and each sequence step. A 20-second start time is substantiated.

The Staff had also requested that data regarding documented diesel generator starting times be provided. Accordingly, Attachment 2 provides a tabulation of starting times for both diesel generators. Included are the date of the sur-veillance, the start time in seconds, and, where retrievable, a brief description

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4 of deficiencies associated with the diesel generators for those instances when 12 seconds was exceeded.

Note that for those instances where "> 12 seconds" is listed, it should not be inferred that 20 seconds was exceeded. In those instances, if the diesel failed to start within 12 seconds, the start signal was automatically interrupted for equipment protective purposes.

We trust the above information is sufficient to allow the NRC Staff to affirma-tively disposition all license amendment requests associated with the Engineered Safety Features.

Very +ruly yours, NORTHEAST NUCLEAR ENERGY COMPANY J

ll/s. xawa-W. G. Counsil Vice President Attachments i

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4 DOCKET NO. 50-336 ATTACRMENT 1 DIESEL GENERATOR LOADING OCTOBER, 1978

i The purpose of the following discussion is to substantiate the acceptability of a 20-second start time for the diesel generators, recognizing that the original design calls for a 12-second start time. It is important to recognize that the associated delay in actuation of Engineered Safety Feature equipment is due ex-clusively to delays in diesel starting, rather than delays or changes in sequencing steps. In other words, sequence step 1 still occurs two (2) seconds following breaker closure, sequence step 2 still occurs six (6) seconds af ter step 1, etc.

A. Permanently Connected Loads (1) Emergency lighting (2) Instruments (3) Battery Charger (4) MOV's (5) Load Center Losses (6) Diesel Air Compressers (7) Service Water Strainer (8) Boric Acid Tank Heaters (9) Boric Acid Heat Tracing (10) 02 Analyzer Exchanger The above items identify the larger components associated with Engineered Safety Feature equipments. Demonstration of the acceptability of these larger components substantiates the acceptability of a 20-second delay time for the permanently connected loads. These loads are immediately re-energized upon diesel generator breaker closure onto its emergency bus and all are capable of withstanding a 20-second interruption delay without compromising their safety function. For example, MOV's need not be moved prior to HPSI or LPSI pumpa delivering flow. A 20-second delay for operation of the battery charger is of no consequence as the batteries alone will support electrical requirements.

B. Sequence Step 1,1.5 - 2.2 seconds after diesel start (1) NOV's - As stated before the valves need not be moved prior to SI pump operation.

(2) [arvice Water Pump - This pump provides cooling water to the RBCCW heat exchangers, and other auxiliary systems. A delay in diesel starting to 20 seconds is not detrimental to these systems. Relative to each other, all components involved are being energized at the same time as in the 12-second start time case.

(3) HPSI Pump - See Reference (2).

(4) Containment Air Recirculation Fans - As stated in response to Question 14.12.1 of the Millstone Unit No. 2 FSAR, Amendment 39, the CAR fans are assumed available 32 seconds following the rupture. The accepta-bility of a 20-second diesel start time is demonstrated as follows.

Time, Seconds Action 0 Rupture 1 SIAS Signal 21 Diesel Breaker Closes 23.2 Sequencer starts CAR fans (includes maximum allowable sequencer tolerance) 28.2 Fans performing design function (assuming 75% of rated voltage available)

Note that the above sequence is only applicable to the single CAR fan tha t is not operating at the time of the incident. The other three CAR fans are operating during nrrmal operation. Assuming a loss of offsite power, these three fans will begin to coast down from the normal operating speed of 1800 RPM. Power will be returned to the fans 23.2 seconds and fan speed will stabilize at the low speed, i.e., accident speed of 900 RPM. This speed will be attained prior to the 28.2 seconds described above.

C. Sequence Step 2, 7.0 - 8.4 seconds af ter diesel start (1) RBCCW Pump - The rationale presented in item B.2, Service Water Pump, is applicable in this instance.

(2) Charging Pumps - No credit is taken in any safety analysis.

(3) Boric Acid Pumps - No credit is taken in any safety analysis.

D. Sequence Step 3, 12.5 - 14.6 seconds af ter diesel start (1) LPSI Pump - See Reference (2).

(2) Containment Sprav Pump - See Reference (2).

s') Enclosure Building Filtration Fan - See Reference (3).

E. Sequence Step 4, 18.0 - 20.8 seconds after diesel start (1) Diesel Generator Vent Fan - An additional eight (8) second delay in energization of this component will not adversely affect diesel genera-tor performance.

(2) HVAC - No adverse affects for an additional eight (8) second delay.

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. . l DOCKET NO. 50-336 AITACHMENT 2 DIESEL GENERATOR START TIMES 1:

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l OCTOBER, 1978

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s j "A" DC START TIMES 1976  !

3/12/76 9 8/23/76 >12(4) 10/27/76 9 4/28/76 8 8/25/76 8.1 11/03/76 9 5/19/76 9 9/01/76 8 11/24/76 9.1 1

6/02/76 19(1) 9/01/76 8 12/01/76 9 4 6/23/76 8 9/10/76 8.3 12/09/76. 8-6/25/70 8.9 9/15/76 9 12/10/76 8 i 7/02/76 8 9/20/76 9 12/16/76 9 i

7/16/76 9 9/22/76 11 12/17/76 9 7/16/76 >12(2) 9/23/76 10 12/17/76 9 8/10/76 >12 (3) 9/29/76 8 12/18/76 8 l 8/13/76 10 10/06/76 8.8 12/18/76 8.2 j 8/16/76 >12(4) 10/06/76 8.7 12/19/76 9 -

8/17/76 >12 (4) 10/13/76 9 12/19/76 9 8/18/76 8.8 10/14/76 8.5 12/19/76 9 8/19/76 9 10/20/76 8 12/20/76 9.2 (1) Not available.

(2) Speed switch failure. 1 (3) Deenergization of RSST. Diesel starts and af ter securing it, attempted ,

l to restart due to emergency start signal prasent. Governor was in "no [

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j fuel" position. Did not start within 12 sec.

(4) Faulty fuel oil booster servomotor.

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"A" DG START TIMES 1977 1/10/77 9 5/04/77 7.8 9/28/77 9 1/10/77 8 5/04/77 8.9 9/29/77 8.7 1/21/77 9.2 6/02/77 8 9/30/77 - 'll

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1/25/77 8 6/29/77 9.2 10/01/77 8.5 2/02/77 8.9 6/30/77 9 10/01/77 9 2/02/77 8 7/06/77 9 10/04/77 8 2/03/77 10 7/13/77 7.8 10/06/77 9 2/03/77 8 7/20/77 9 10/11/77 8.25 2/09/77 9 7/27/77 8.6 10/11/77 8.4 2/10/77 8 8/03/77 9 10/20/77 8.4 2/16/77 8.8 8/10/77 8.5 10/26/77 8 2/16/77 9 8/17/77 8 11/01/77 8.2 2/23/77 8.8 8/23/77 9 11/08/77 9 3/02/77 10 8/27/77 8.5 11/09/77 9 3/09/77 9.4 8/28/77 8.5 11/15/77 S.5 3/16/77 8.5 8/30/77 9.2 11/28/77 8.4 3/23/77 9 9/06/77 9.2 12/06/77 9 3/30/77 8.8 9/13/77 9 4/06/77 9 9/20/77 8.8 4/13/77 8.3 9/21/77 8.4 4/20/77 8.6 9/27/77 9 4/27/77 9 9/28/77 9

"A" DG START TIMES 1978 2/23/78 8.5 6/06/78 8.4 2/24/78 8.5 6/14/78 9 3/10/78 9.5 6/20/78 9 3/22/78 8.5 6/27/78 9 2/28/78 8.3 7/05/78 9 4/07/78 8.6 7/11/78 9 4/13/78 8.7 7/13/78 9 4/26/78 8 7/26/78 9 5/03/78 9 7/27/78 9 5/03/78 9 7/28/78 9 5/05/78 9 8/03/78 9 5/06/78 9.8 8 /03/78. 9 5/07/78 8 8/08/78 8.2 5/ 08 /78 9 8/09/78 9 l 5/08/78 8 8/15/78 8 5/10/78 9 8/29/78 8 5/11/78 8 9/05/78 9 5/17/78 8.4 9/16/78 8.5 5/18/78 8.5 9/12/78 10 l

5/24/78 8 9/19/78 8 L

5/31/78 8.6 10/03/78 9

.- 9 "B" DG START TIMES 1976 3/11/76 8.5 8/17/76 12 10/14/76 9 3/12/76 8.8 8/18/76 8 10j27/76 8 3/16/76 8.5 8/18/76 9.0 ~_ - 10/27/76 8 4/15/76 8 8/23/76 11 ,y, ,

-11/03/76 8

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6/03/76 10 '8/24/76 8.5 I '+ 11/04/76 9 6/16/76 9.3 8/24/76 8.8 11/10/76 8 6/23/76 8.2 8/25/76 8.9 11/13/76 9 6/24/76 8 9/03/76 8 11/19/76 9 6/25/76 8 9/10/76 8 11/24/76 9 7/14/76 9 9/17/76 8 12/01/76 8.6 7/16/76 11.5 9/22/7t, 10 12/08/76 8.7 7/21/76 8 .9/23/76 10 12/09/76 9.2 7/27/76 9.5 9/28/76 7 12/09/76 8.8 8/13/76 8.7 10/06/76 9 12/17/76 9 8/17/76 8.8 10/13/76 8 12/17/76 9 j 12/18/76 9 4

-. . - - _ = -- . . _

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"B" DG START TIMES 1977 1/05/77 8 6/08/77 9.6 9/13/77 9 1/11/77 8 6/17/77 8.5 9/20/77 9 1/20/77 9 6/24/77 8.2 9/20/77 9 1/25/77 8 6/29/77 9 9/21/77 8.2 2/09/77 9 7/06/77 9 9/22/77 8.4 2/10/77 9 7/13/77 9 9/23/77 8.4 2/16/77 9 7/20/77 9 9/28/77 9 2/23/77 9 7/27/77 8.8 10/04/77 8.5

, 3/02/77 8 8/03/77 9.2 10/06/77 8.8 3/09/77 9.2 8/10/77 9 10/13/77 9

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3/ 09/77 8.4 8/17/77 9 10/11/77 9.6 3/16/77 8.8 8/17/77 9 10/18/77 8.9 3/23/77 9 8/23/77 9 10/25/77 9 3/30/77 9 8/26/77 9 11/01/77 8.9 4/06/77 9 8/27/77 8.5 11/09/77 8.6 4/13/77 9 8/27/77 9 11/15/77 9.1 4/20/77 9 8/27/77 8.6 11/17/77 9 4/27/77 8.5 8/28/77 9 12/13/77 9.2 5/04/77 8.5 8/29/77 8.5 12/26/77 9 5/16/77 8 8/30/77 8.7 l 5/31/77 9 9/06/77 '8.9 i

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2 j "B" START TIMES 1978 1/18/78 8 5/08/78 8 7/11/78 8.5

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2/19/78 9 5/10/78 9.4 7/13/78 9 L -

t' 2/28/78 9 5/18/78 9 7/18/78 9 b- 3/10/78 8 5/25/78 9 7/25/78 9 3/15/78 11 5/31/78 9.5 8/03/78 9 3/16/78 9 6/06/78 9 8/03/78 9

3/29/78 8.9 6/14/78 10 8/08/78 9.9 j 4/14/78 9.0 6/20/78 9 8/15/78 8.6 4/19/78 8.8 6/27/78 9 8/22/78 9 5/03/78 9 7/06/78 8.7 8/29/78 8.5 9/05/78 9 9/06/78 9 3 9/12/78 8.5 i

9/19/78 9 9/26/78 9 4

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