L-80-304, Forwards Response to NRC 800721 Request for Addl Info Re Adequacy of Station Electric Distribution Sys Voltages

Forwards Response to NRC 800721 Request for Addl Info Re Adequacy of Station Electric Distribution Sys Voltages

ML17208A996
Person / Time
Site:	Saint Lucie
Issue date:	09/12/1980
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
L-80-304, NUDOCS 8009180444
Download: ML17208A996 (7)

Text

REGULATORY INFORMAT'ION DISTRIBUTION SYSTEM (RIDS)

ACCkSSTON NBR:0009100444 DOC ~ DATE: 00/09/12 NOTAOZEDi NO FACIL:50-335 St., Lbcje Plant'R Unit 1Rlor fda Power 8 Light Co ~

AUTH ~ NAME AUTHOR AFFILIATION UHRIGR R ~ E ~

F11 or i da Power 8 Light Co, REC IP ~ NAME RECIPIENT" AFFILIATION EISENHUTRD.G, Division of L:icensing

SUBJECT:

Forwards response to NRC 800721-request for addi info re adequacy of station electric distribution-sys voltages.

DISTRIBUTION CDDE:

A015S COPIES RECEIVED:L'TR 2-'NCL( l-SIZE' TITLE: Onsite Emergency Power Systems NOTES!

DOCKET 05000335 RECIPIENT-.

ID CODE'/NAME'CTIONS CLARKRR ~

04 INTERNALt: AEOD I8C SYS BR 09 MPA 1B OELD 17 OR SS BR 12 FIL 01 COPIES LtTTR ENCL' 7

i.

1 1

1 1

1 1

1 1

1 1

1 REC'IP'I ENT ID CODE/NAMEl GEN ISSUES BR13 I 8 E".

06 NRCA PDR 02 OP EX EVAL". BR11 POWER SYS BR'4 COPIES LTTR ENCL 1

1 2

2 1

1 1

1 1

1 EXTERNAL: ACRSNSIC'6 05 16 16 1

LPDR 03 1

1

~E~ >> iso TOTAL NUMBER OF COP'IES REQUIRED:

L'.fTR 37 ENCL!

37

e 5

('I 5 "-.If '(

((

<c 5

r Ih

(

(

((

(1 "l.

II 5

'(55 5

5 '),( li

'h5%')(f(( "'5 II (l'f r

'5 ">

~ >

5 f

j" 0

<<(s C

l l

5 I

~ 4 Q

(

l&Aw'A%

FLORIDA POWER 4 LIGHTCOMPANY September 12, 1980 L-80-304 Office of Nuclear Reactor Regulation Attention:

Mr. Darrell G. Eisenhut, Director Division of Licensing U.

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

Dear Mr. Eisenhut:

Re:

St. Lucie Unit 1 Docket No. 50-335

~Af~iY 1 Our response to an NRC letter dated July 21, 1980, requesting additional information on the adequacy of station electric distribution system voltages is attached.

Very truly yours, Ro ert E. Uhrig

-'ce President Advanced Systems 8 Technology REU/PLP/pah cc:

J.

P. O'Reilly, Region II Harold F. Reis, Esquire go(s 5

ii) 8009X8O llflt/f PEOPLE... SERVING PEOPLE

ATTACHMENT Re:

Request for Additional Information - St. Lucie Unit 1, Adequacy of Station Electric Distribution System Voltages Reference 1:

FPL letter (L-79-324) to NRC (W. Gammill) dated November 9; 1979

Response

to guestion 1

1.

Paragraph 3 page 4 (reference

1) provides the response to question 1

guideline 1.

Because either a unit trip or safety injection signal initiates automatic transfer of the onsite distribution system from the auxiliary transformer to the start-up transformer, the voltage analyses were performed assuming connection to the start-up transformer.

Two cases were analyzed, one with normal running loads being supplied by the start-up transformer (unit trip) and the other with safety loads being simultaneously started without tripping the normal running loads (accident condition).

All automatic actions were assumed to occur as designed and ny.credit was taken for manual load shedding.

Paragraph 2 page 5 (reference

1) provides the response to question 1

guideline 7.

In addition the voltages for the conditions analyzed are furnished in Table A (attached).

Two cases were analyzed.

Case 1 with normal running loads being supplied by the start-up transformer (unit trip) and Case 2 with safety loads being simultaneously started without tripping the.normal running loads (accident condition) as stated in "

reference l.

Voltage conditions less than 230 kV are considered to be short term and transient in nature with recovery or collapse of t4e'ystem expected to occur in a short period of time.

The voltage at all safety related equipment would be sufficient for their continued operation should the plant trip and all loads be transferred to the start-up transformer.

The studies were performed with the grid at 230 kv.

la. Paragraph 2 page 4 (reference

1) provides the response to question la, guideline 6.

The minimum expected voltage value at St. Lucie Unit 1 is 230 kV.

Voltages below 230 kV are considered to be short term and transient.

Table A contains the calculated voltages for the conditions analyzed at the grid voltage of 230 kV.

The voltage analysis results for grid voltage at 244 kV are documented in table A case 3.

The voltages calculated do not exceed the maximum voltage rating of any safety related e'quipment.

The assumptions made are those given in paragraph 3 page 4 (reference 1).

Concerns of question la, guidelines 5 and 12 have been addressed in pages 4 and 5 (reference 1)-

lb. St. Lucie Unit 1 safety related instruments are fed through inverters by batteries.

Grid voltage oscillations therefore have no effect on these instruments.

1c.

The assumptions given in pages 4 and 5-(reference

.1) addressed guestion 1c guidelines 3, 4, and 9.

Since no credit for manual load shedding was taken, in cmpliance with guideline 4, non-class 1E loads remained connected for the calculation.

Therefore, consideration of starting the condensate pump was not made because it was already considered to be running.

1d. Although it is possible to backfeed the plant from the grid through the main transformer bank, the generator would not be operated in this configuration.

Response

to guestion 2

St. Lucie Unit 1 FSAR chapter 88 (sections

8. 1.2. 1 and 8.2.2) provides the requested review which shows compliance with GDC-17.

Response

to guestion 3

Table A'rovides the voltage analysis results for the adequacy of the onsite distribution system from offsite sources.

Analytical results were within'2X using the same methods and.assumptions and the actual plant configuration of data obtained by plant personnel using standard plant test

, methods.

l

Response

to guestions 4 and 5

The addition of undervoltage relays on the 480 volt class 1E busses assures that the manufacturer's guaranteed pickup point can be met.

In addition, as indicated in letter (L-80-212) dated July 3, 1980 responding to a May 29, 1980 request for additional information, an October 1980 completion date was expected for further investigation of the H-2 relay set points.

Due to subsequent new requests for additional information on Grid voltages the above mentioned investigations are not expected to be completed until January 1981.

(Note: guestions 4 and 5 appear to answer one another)

TABLE A VOLTAGE ANALYSIS Bus Case 1

Case 2

Case 3

4 KV. Non Safety Related Bus voltage 4 KV, Safety related bus voltage 480 volt safety related load center voltage Voltage at safety related MCC 5 Voltage at. safety related MCC 6

Voltage at safety related MCC 7 Voltage at safety related MCC 8 4011 4007 458 450 450 449 450 3797 3768 423 408 407 408 409 4264 4260 488 479 480 479 480 Case 1

Normal running loads being supplied by the start up transformer (unit trip from full load with transfer of the loads to the start-up transformer.

Case 2

Same as case 1 with a concurrent accident condition Case 3

- Same as case 1 at maximum grid voltage

E