ML20217B050

From kanterella
Jump to navigation Jump to search
Provides Listed Info as Result of 980213 Telcon Held Between Util & NRC Re Proposed Amend to Revise LCO 3.8.1, AC Sources - Operating, to Allow EDG to Be OOS for Up to 14 Days
ML20217B050
Person / Time
Site: Vogtle  Southern Nuclear icon.png
Issue date: 03/18/1998
From: Mccoy C
SOUTHERN NUCLEAR OPERATING CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LCV-1111-A, M96769, M96770, NUDOCS 9803250340
Download: ML20217B050 (6)
v • d • e


Text

.- 4

. C.K. McCoy Southern Nuclear

- , . Mce President Operating Company. loc.

1 Vogtle Project 40 inverras Center Parkway P0. Box 1295 Birmingham, Alabama 35201 Tel 205992.7122 Fax 2059920403 SOUTHERN COMPANY Harch 18,-1998 EnergytoServe YourWorld*

LCV-I l ll-A Docket Nos. 50-424 50-425 TAC Nos. M96769 M96770 U. S. Nuclear Regulatory Commission A'ITN: Document Control Desk Washington, D. C. 20555 VOGTLE ELECTRIC GENERATING PLANT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION AND REQUEST TO REVISE TECilNICAL SPECIFICATIONS, "AC SOURCES - OPERATING" EMERGENCY DIESEL GENERATOR EXTENDED AOT REQUEST Ladies and Gentlemen:

Ily letter dated January 22,1998, (LCV-1111) Southern Nuclear Operating Company (SNC) proposed to amend the Vogtle Electric Generating Plant (VEGP) Unit 1 and Unit 2 Technical Specifications (TS), Appendix A to Operating Licenses NPF-68 and NPF-81. The proposed amendment would revise Limiting Condition for Operation (LCO) 3.8.1, AC Sources -

Operating, to allow an emergency diesel generator (DG) to be out of service for up to 14 days.

On February 13,1998, a telephone conversation was held between SNC and the NRC staff regarding the proposed amendment. As a result of that telephone conversation, SNC is providing the following information:

~

  • From the current revision zero (Rev. 0) converted model, the percentagc of the total average core damage frequency (CDF) attributed to station blackout (SILO), single unit loss of offsite power (LOSP1), and dual unit LOSP (LOSP2) is:

Current Rev. O Converted Model l

Contributor Percent of Total Average CDF Silo 5.6 %

LOSP1 8.5 %

LOSP2 2.7 %

9803250340 980318 PDR ADOCK 05000424 P pyg

._ . t.

.- U. S. Nuclear Rrgul: tory Commission

.- LCV-1111-A !

Page 2

  • From the current revision zero (Rev. 0) converted model with the standby auxiliary:

transformer (SAT) failed, the percentage of the total average CDF attributed to SBO, single unit LOSP (LOSPI), and dual unit LOSP (LOSP2)is:

Current Rev. O Converted Model with SAT Failed Contributor Percent of Total Average CDF SBO 6.0 %

LOSP) 28 %

LOSP2 9.0 %

  • Quantification of the current revision zero (Rev. 0) converted model yielded an average large early release frequency (LERF) of 1.72E-06 per year. With the failure of both DGs, the total average LERF calculated was 1.72E-06 per year which is the same as that calculated for the base case. Therefore, there is no increase in average LERF due to the

. failure of both DGs.

During a subsequent review, it was identified that an inappropriate recovery rules file was used to make the calculations reported in LCV-Illi. As a result, the information reported in LCV-1111. Enclosure 3, SNC Response to NRC Question 2, is revised as follows:

(a) The decrease in the average CDF when credit is taken for the availability of Plant Wilson will be:

CDF decrease = (CDF A - CDF B)

= (4.831E 3.641E-05)/4.831E-05

  • 100%

= 24.6%

(b) No change.-

(c) No change.

. (d) No change.

f

. (e) The following baseline CDFs were calculated:

]

Non-hurricane season CDFo = 3.620E-05/ year

- Hurricane season CDFG = . 3.798E-05/ year t . Annual Average .CDFB = 3.641E-05/ year j

i? .j j

, , 1

. U.'S, Nuclear Regulitory Commission

. LCV-1111-A Page 3

~

l (f) Change in the CDP during non-hurricane season with EDG A in maintenance for 14 days and EDG-B not in maintenance will be:

DCDP = (CDF E - CDF p + dCDF SEISMIC + TORNADO)

  • 14/365

=- (4.226E 3.620E-05 + 2.53E-06)

  • 14/365

= 3.29E-07 Change in the CDP during non-hurricane season with EDG-B in maintenance for 14 days and EDG-A not in maintenance will be:

DCDP = (CDF p - CDF D + dCDF SEISMIC + TORNADO)

  • 14/365

=

(4.424E 3.620E-05 + 2.53E-06)

  • 14/365

= 4.05E-07 Change in the CDP during hurricane season with EDG-A in maintenance for 14 days and EDG-B not in maintenance will be:

l DCDP = (CDF }{ - CDF o + dCDF SEISMIC + TORNADO)

  • 14/365

=

(4.643E 3.798E-05 + 2.53E-06 )

  • 14/365

= 4.21 E-07 1

Change in the CDP during hurricane season with EDG-B in maintenance for 14 days and j EDG-A not in maintenance will be: J DCDP = (CDF 1-CDF G +dCDF SEISMIC + TORNADO)

  • 14/365

=

(4.955E 3.798E-05 +2.53E-06)

  • 14/365

= 5.41 E-07 Change in the CDP using average values for LOSP1 (single unit LOSP) and LOSP2 (dual ,

unit LOSP) with EDG-A in maintenance for 14 days and EDG-B not in maintenance will be:

l

)

DCDP =- (CDF j - CDF B + dCDF SEISMIC + TORNADO)

  • 14/365

=

(4.276E 3.641 E-05 + 2.53E-06) *' 14/365  ;

= 3.41 E-07 Change in the CDP using average values fo.* LOSP1 and LOSP2 with EDG-B in maintenance for 14 days and EDG-A not in mairtenance will be:

- DCDP = - (CDF K - CDF B + dCDF SEISMIC + TORNADO)

  • 14/365

=

(4.485E 3.641E-05 + 2.53E-06)

  • 14/365

= 4.21E-07 -I i

o

.j

'a ,' ' 'U', ,S N luc ear Regul: tory Commission

.-  : LCV-1111-A - 1 Page 4 (g) No change.

(h) To determine the instantaneous change in the CDF value for the potential worst-case plant configuration allowed under the proposed technical specifications, two cases were evaluated '

to determine the impact on instantaneous CDF if additional equipment was out of service

' during a diesel generator extended AOT. VEGP Technical Specifications allow the turbine driven AFW pump or a train of NSCW associated with the EDG to be out of service at the same time.

Case 1: TDAFW pump and EDG-A in raaintenance: Change in the VEGP CDF using average values for LOSP1 and LOSP2 with EDG-A and TDAFW pump in maintenance, and EDG-B and MDAFW pumps not in maintenance will be :

dCDF = (CDF L -CDF B + dCDF SEISMIC + TORNADO)

=

(6.837E 3.641E-05 + 2.53E-06)

= 3.449E-05 Case 2: NSCW train B and EDG-B in maintenance: Change in the VEGP CDF using average values for LOSP1 and LOSP2 with EDG-B and NSCW train B in maintenance, and EDG-A and NSCW train A not in maintenance will bc :

dCDF = CDF M -CDF B + dCDF SEIS'MIC + TORNADO)

=

(7.981E 3.641E-05 +2.53E-06)

= 7.642E-04 Please see revised Table 1 on the next page.

)

i '

s i2.mmim --._ --

ih i , . - s.- 4 s i i1-i p t

,~ U S. Nuclear R gulatory Commission

  • ~

. LCV-1111-A -

Page 5 1

TABLEI CDF Variables used in EDG Extended AOT Justification Calculations CDF -CDF DUAL UNIT LOSP DESCRIPTION OF CDF VARIAHLE VARIABLE VALUE FREQUENCY CDF 4 4.831 E-05 1.43E-02 Average annual CDF with no credit for SAT CDFn 3.641E-05 1.43 E-02 Average annual CDF with credit for SAT .

dCDF susuic. 2.53 E-06 N/A CDF contribution from Seismic and Tornado anno events CDFo 3.620E-05 1.13 E-02 Average annual non-hurricane season CDF with credit for SAT CDF, 4.226E-05 1.13 E-02 Average annual non-hurricane season CDF with credit for SAT, assuming EDG-A in maintenance and EDG-B not in maintenance CDF, 4.424E-05 1.13E-02 Average annual non-hurricane season CDF with no credit for SAT, assuming EDG-B in maintenance and EDG-A not in maintenance CDFo 3.798E-05 3.61E-02 Average annual hurricane season CDF with credit for SAT CDFu 4.643 E-5 3.61 E-02 Average annual hurricane season CDF with credit for SAT, assuming EDG-A in maintenance and EDG-B not in maintenance CDF 4.955E-5 3.61 E-02 Average annual hurricane season CDF with credit for SAT, assuming EDG-B in maintenance and EDG-A not in maintenance CDF, 4.276E-05 1.43 E-02 Average annual CDF with credit for SAT, assuming EDG-A in maintenance and EDG-B not in maintenance CDFx 4.485E-05 1.43E-02 Average annual CDF with credit for SAT, assuming EDG-B in maintenance and EDG-A not in maintenance CDF.i 6.837E-05 1.43 E-02 Average annual CDF with credit for SAT, assuming EDG-A and TDAFW in maintenance, and EDG-B and MDAFW pumps not in maintenance CDFu 7.981 E-4 1.43 E-02 Average annual CDF with credit for SAT, assuming EDG-B and NSCW train B in maintenance, and EDG-A and NSCW train A not in maintenance 4

b l J

p 1

',. . if .S. Nuclear Regulatory Commission ,

.~- LCV-I l l i-A' ' -

- - Page 6 During our telephone conversation of February 13,1998, the NRC staff asked about our policy regarding entry into an extended DG AOT in the event ofimpending severe weather. We referred the staff to our submit"I LCV-1111, Enclosure 2, page 7 which contains the following statement:

  • 1 An EDG extended A'OT will not be entered for scheduled maintenance purposes if severe weather conditions are expected.

On page 8 of Enclosure 2 to LCV-1111, SNC states that VEGP will have procedures in place to implement the above commitment (plus the other commitments discussed on pages 7 and 8 of Enclosure 2 to LCV-1111) prior to entering an extended DG AOT.

i Finally, SNC notes that our submittal LCV.l l l 1 pmvided definitions of Level 1, Level 2, and Level 3 PRAs which has apparently been a source of confusion. The definition of a Level 3 PRA was not intended to imply that SNC uses a Level 3 PRA. SNC does not use or possess a Level 3 PRA for the Configuration Risk Management Program (CRMP) nor for any other purpose.

Should you have any questions or need further information, please contact this office.

Sincerely, C. K. McCoy CKM/NJS cc: Southern Nuclear Operating Company Mr. J. B. Beasley, General Manager, VEGP Mr. M. Sheibani, NSAC Supervisor, VEGP NORMS U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. D.11. Jaffe, Senior Project Manager, NRR ,

Mr. John Zeiler, Senior Resident inspector, VEGP 1

Retrieved from "https://kanterella.com/w/index.php?title=ML20217B050&oldid=3229209"