ML17308A487
| ML17308A487 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/07/1990 |
| From: | Sager D FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML17223A576 | List: |
| References | |
| L-90-58, NUDOCS 9003150418 | |
| Download: ML17308A487 (85) | |
Text
ACC",ELERATED DILUTION DEMONSHQTION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9003150418 DOC.DATE: 90/03/07 NOTARIZED: NO DOCKET FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power & Light Co. 05000335 50-389 St. Lucie Plant, Unit 2, Florida Power & Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION SAGER,D.A. Florida Power & Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
Forwards response to eight audit questions aM'UBJECT:
& licensing bases criteria to resolve station balckout.
DISTRIBUTION CODE: A050D COPIES RECEIVED:LTR ~
ENCL l SIZE: 55 TITLE: OR Submittal: Station Blackout (USI A-44) .10CFR50.63, MPA A-22 NOTES:
RECIPIENT COPIES RECIPIENT COPIES A ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 PD 1 1 NORRIS,J 1 1 INTERNAL: ACRS 1 1 NRR PD1-4PM TAM 1 1 NRR/DET/ESGB 8D 2 2 NRR/DST/S PLB8 D1 2 2
.1 1 NUDOCS-ABSTRACT 1 1 EG FIL 01 1 1 EXTERNAL: LPDR 1 1 NRC PDR NSIC 1 1
.D NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE, DOCUMENT CONTROL DESK)
ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDl TOTAL NUMBER OF COPIES REQUIRED: LTTR 14 ENCL 14
P.O. Box14000, Juno Beach, Fl 33408-0420 MNGB OV ~99 L-90-58 10 CFR 50.63 U. S. Nuclear~Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re: St. Lucie Units 1 and 2 Docket Nos. 50-335 and 50-389 Information to Resolve Station Blackout On July 21, 1988 the Nuclear Regulatory Commission (NRC) amended its regulation to 10 CFR Part 50 by adding a new section 10 CFR 50.63. This new regulation requires the St. Lucie nuclear site to withstand a total loss of all AC power on one unit (unit blackout),
following loss of offsite power to the site. On April 17, 1989 FPL submitted information required to resolve unit blackout in FPL letter L-89-145 pursuant to 10 CFR 50.63.
During October 17-19, 1989 the NRC conducted an audit of FPL's response to resolve this issue. Eight (8) NRC questions were addressed by FPL at the audit, one of which was determined to be an industry generic unresolved issue.
In response to the unresolved issue, NUMARC representatives met with the NRC staff on November 8, 1989. During this meeting the NRC staff provided guidance that issue.
if followed would resolve the The proposed FPL design will use a class 1E, safety related, seismically and weather protected unit intertie to mitigate the effects of a unit blackout. The intertie is capable of supplying emergency power to any safety related bus on the "blacked-out" unit from any emergency diesel generator bus from the non "blacked-out" unit. This proposed intertie, as described in L-89-145, complies with the NRC guidance and resolves this issue for St. Lucie Units 1 and 2.
Attachment (I) to this letter is FPL's response to the eight. (8)
NRC specific questions discussed during the audit. Attachment (II) provides the FPL licensing bases criteria to resolve station blackout.
9003i50418 900307 05000335 PDR ADOCK an FPL Group company
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L-90-58 Page 2 of 2 FPL is requesting that the NRC pre-approve safety grade design changes at the St. Lucie facility pursuant to 10 CFR 50.63 based on criteria provided in attachment (II) of this letter and FPL Letter L-89-145. As demonstrated during the audit this document meets 10 CFR 50.63 criteria and utilizes guidance provided in Regulatory Guide 1.155 and NUMARC 87-00.
If there are any questions, please contact us.
Very truly yours, D. A. er Site e President St. Luc e Plant DAS/RWG/rh List of Attachments:
I ~ FPL Response to Eight Audit Questions (9 Pages) a ~ Enclosure 1 for FPL Response to NRC Question 1 (25 pages) ~
- b. Enclosure 2 for FPL Response to NRC Question 2 (8 pages).
C~ Enclosure 3 for FPL Response to NRC Question 3 (12 pages)-
- d. Enclosure 4 for FPL Response to NRC Question 4 (5 pages).
- e. Enclosure 5 for FPL Response to NRC Question 5 (4 pages).
- f. Enclosure 6 for FPL Response to NRC Question 7 (18 pages).
Licensing Basis Criteria to Resolve Station Blackout for Florida Power & Light St. Lucie Nuclear Units (5 pages).
CC Stewart D. Ebneter, Regional Administrator, Region II, USNRC (2 copies)
Senior Resident Inspector, USNRC, St. Lucie Plant
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TO FPL LETTER L-90-58 RESPONSE TO EIGHT AUDIT QUESTIONS gp08150418
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0 'RC uestion:
Discuss why the plants should not be classified as P3 sites in accordance with NUMARC 87-00 Section 3.2.1 Part 1.A.
PPL Res onse!
FPL's bases for determining the offsite power design characteristic group was analyzed using guidance provided in Regulatory Guide 1.155.
During the October 17-19 station blackout audit FPL presented, in detail, the results of FPL's analysis to confirm a P2 characterization from the results obtained using Table 2 through 8 in Regulatory Guide 1.155.
The results of that presentation are provided below:
A) Table 8 of R. G. 1.155 >>DEFINITION OP EXTREMELY SEVERE WEATHER ESW GROUP>s:
In FPL's submittal for St. Lucie (L-89-145), dated April 17, 1989) each unit at the site was characterized as ESW Group 4 (i.e. 3.3 x 10 <e< 1 x 10 ') .
Hurricane frequency for the St. Lucie nuclear site was studied for the NRC by Sandia National Laboratory (i.e. NUREG/GR-4710, SAND 86-1797) and for FPL by Dames and Moore (Draft f4598-144-09). The mean value of wind speed frequencies for 125 mph as reported by Sandia and Dames and Moore is 6.25x10
'/yr and 3.9x10 '/yr respectively. Both studies have used data from the U. S. Weather Bureau. The results define the extremely severe weather groups for St. Lucie as ESW Group 4 (i.e., 3.3xl0 <e<lx10 ).
The numbers provided in FPL's submittals were determined by linear extrapolation of the data provided to the NRC auditors.
The data is provided as Enclosure 1 to this response.
B) Table 7 of R. G. 1.155 ~~DEFINITION OP SEVERE WEATHER RE COVE Y SWR GROUPs' Pursuant to FPL submittal of April 17, 1989 each unit at the site was characterized as SWR Group 1.
FPL walked through a number of system restoration procedures with NRC auditors during the October 17-'19 review. These procedures encompassed the following:
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0 System Restoration 0 Restoration of off-site power to nuclear plants-Turkey Point 0 Restoration of off-site power to nuclear plants-St. Lucie 0 Black start-general 0 FPL's real time analysis for single contingency
. Loss of a transmission line or generator.
In addition, FPL demonstrated the effectiveness of these procedures by review of actual system disturbances which occurred on the FPL grid in May 17, 1985 (recovery made in 44 minutes) and August 20, 1989 (recovery made in 20 seconds).
Excerpts from these reports have been provided to the NRC auditors and are provided as enclosure (1) to this response.
C) TABLE 6 OF R.G. 1.155 >>DEFINITION OF SEVERE WEATHER SW GROUP'~:
Regulatory Guide 1.155, Revision 1, changed the frequency numbers for determining Severe Weather (SW) group. This change necessitated a re-characterization of the SW group for both units to SW group 1. This change did not effect the results of FPL's analysis.
Severe Weather (SW) group frequencies, as reported in FPL's April 17, 1989 submittals, have been calculated to be 2.67z10 'or the St. Lucie site.
NUMARC 87-00 data (Table 3-3) was used as guidance to determine the input. parameters for the formula in R.G. 1.155 table 6. The SW group determination does not impact the final classification of the St. Lucie site. Thus, the validity of the NUMARC 87-00 data was not challenged.
D) TABLE 5 R G 1 ~ 155 '>DEFINITION OF INDEPENDENCE OF OFFSITE POWER I GROUP>>:
St. Lucie site has been characterized as an I2 group. See FPL response to NRC question (2).
E) TABLE 4 R.G. 1. 155 ~~OFFSITE POWER DESIGN CHARACTERISTIC P GROUP'i.
Pursuant to FPL's submittal of April 17, 1989 and amended discussions during the October 17 audit FPL characterized the St. Lucie site as P2.
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The basis for the "Offsite Power Design Characteristic Group (P-Group)" for both units are summarized below by depicting the results of FPL's analysis of Regulatory Guide 1.155 tables 8 through 4:
Extremely Severe Weather (ESW) Group ~ ~ ~ ~ ~ ~ ~ ~ 4 Severe Weather Recovery (SWR) Group ~ ~ ~ ~ ~ ~ ~ ~ 1 Severe Weather (SW) Group ~ ~ ~ ~ ~ ~ ~ ~ 1 Independence of Offsite Power Group ~ ~ ~ ~ ~ ~ ~ ~ I 2 Beginning from Table 4, P3 Group, the site has experienced a total loss of offsite power caused by grid failures at a frequency equal to or greater than once in 20 site years.
However, the site has demonstrated, by procedures, they can recover AC power from reliable alternate (non emergency) ac power sources within approximately one-half hour following a grid failure.
Thus, a P3 characterization is possible only with "any combination of" the factors provided in table 4. Regulatory Guide 1.155, Table 4, depicts six (6) different site combinations to qualify as P3.
Power Group (I2) eliminates the sixth combination for both FPL units.
Power Group (I2) and severe weather (SW) group (1) eliminates all, but, the second combination for the site.
Power Group (I2), Severe Weather (SW) group (1), Severe Weather Recovery (SWR) group (1) and extremely severe weather (ESW) group (4) eliminates all combinations for both FPL units.
The St. Lucie site does not meet the combinations of Pl in accordance with the procedures in Regulatory Guide 1.155; therefore, P2 was selected.
NRC UESTION.
Discuss how the plants meet (will meet) the offsite power system Group I2 criteria by referring to NUMARC 87-00 page 3-11 or Regulatory Guide 1.155 Table 5, p.12.
PPL RESPONSEt FPL has concluded that the existing and future configuration of St. Lucie Units 1 and 2 offsite power sources, switchyard and onsite distribution system to the safe-shutdown buses places St. Lucie site into the Offsite Power Group (OPG) "I2" category of Reg. Guide 1.155 Table 5. This determination is based on the satisfaction of the following Reg. Guide criteria:
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A) CATEGORY 1 itINDEPENDENCE OF OFFSITE POWER SOURCES<>
St. Lucie utilizes one (1) common switchyard which effectively ties the St. Lucie plant to the transmission grid by three (3) independent 240 KV transmission circuits to the Midway substation. The design of the offsite transmission system and switchyard meet the intent of General Design Criterion 17 due to their circuit independence, redundancy and isolation capability as discussed in the St. Lucie FSARs.
Therefore, Category 1.a under Offsite Power Group (OPG) X2/I3 is satisfied as the St. Lucie switchyard reflects the description, "All offsite sources are connected to the plant through one switchyard".
B) CATEGORY 2 IsAUTOMATIC AND MANUAL TRANSFER SCHEMES FOR THE CLASS 1E BUSES WHEN THE NORMAL SOURCE OF AC POWER FAILS AND WHEN THE BACK UP SOURCES OF OFFSITE POWER FAIL."
The St. Lucie design is represented by Sub-Category 2a. "The normal source of AC power is assumed to be the Unit main generator (G1 or G2)." The OPG I2 Category 2a criteria states the following:
"After loss of the normal AC power source, there is an automatic transfer of all safe-shutdown buses to one preferred alternate power source. Zf this source fails, there may be one or more manual transfers of power source to the remaining preferred or alternate offsite power sources."
The St. Lucie design exceeds this criteria as following the loss of Gl or G2 the automatic transfer consists of two (2) independent and concurrent transfers of all safe-shutdown buses from the main generator/auxiliary transformers sources to two separate preferred alternate power sources leading into the switchyard. At St. Lucie, the Train A and Train B Class 1E buses are fed by A and B Start-up transformers respectively for each unit. Each Start-up transformer is fed by a separate circuit leading into the switchyard which in turn are fed by the three (3) transmission lines to midway substation, any of which can provide dual unit shutdown power.
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Upon failure of one of two of the preferred alternate power sources, either the A or B train switchyard to start-up transformer circuit, a remaining manual transfer is available to restore power to the lost train, A or B, via the manual cross-tie breakers 2B4 or 2A4 to the opposite units auxiliary transformers respectively.
In all cases, for purposes of meeting the OPG I2 Category 2a.
criteria, all class 1E buses remain energized from offsite power. to Attachment I for this response provide additional discussion, FSAR sections and diagrams depicting the above information.
NRC UESTION'onfirm that the plants'rocedures have been reviewed, and have been (or will be) modified to meet the station blackout response guidelines per NUMARC 87-00, Section 4.2.1, the AC power restoration guidelines per Section 4.2.2 and the severe weather guideline of Section 4.2.3 Identify and discuss any exceptions to the guidelines.
FPL RESPONSE St. Lucie currently has pi"ocedures to mitigate effects of hurricanes and tornados. FPL procedures meet or exceed NUMARC 87-00 guidelines. However, as committed in FPL's station blackout (SBO) submittal of .April 17, 1989, site procedures will be modified and revised to include:
a) procedures to electrically cross-connect units in 10 minutes from the control room and to mitigate the effects of a unit blackout.
b) procedures to commence unit shutdown 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> prior to the projected onset of hurricane force winds at the site.
Procedure modifications will be completed as part of implementing SBO modifications at FPL sites. Enclosure (3) to this response to St. Lucie's site procedure is currently in use to address hurricanes and tornados.
NRC UEST ION Provide the number of gallons of water required for decay heat removal during the four-hour coping duration and the minimum permissible condensate storage tank. level per Technical Specifications. If additional water sources are necessary for decay heat removal, identify these, list the number of gallons provided by each source and identify any plant modifications and/or procedure changes needed to utilize these water sources (PTN and PSL) .
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PPL RESPONSEi The St. Lucie Unit 1 condensate storage system consists of a 250,000 gallon capacity condensate storage tank (CST) which serves as the source of water to the auxiliary feedwater (AFW) system. The St. Lucie Unit 1 Technical Specification Limiting Condition for Operation (LCO) requires a minimum contained volume of 116,000 gallons in the CST. Several analyses have been performed to verify the adequacy of the St. Lucie Unit 1 condensate storage system. Figure 10.5-1 of the St. Lucie Unit 1 FSAR (attached) indicates the amount of condensate required to maintain. the plant in a hot standby condition.
From this figure it can be seen that approximately 62,000 gallons of condensate are required to remove decay heat and maintain the plant in hot standby for the four hour station blackout duration. Note that figure 10.5-1 also includes 28,000 gallons of condensate to restore steam generator level.
The St. Lucie Unit 2 condensate storage system consists of a 400,000 gallon capacity CST with a corresponding Technical Specification LCO minimum contained volume requirement of 307,000 gallons. The condensate storage requirements for the St. Lucie Unit 2 AFW System were compared to the requirements of Regulatory Guide 1.139; The results of this analysis concluded that 60,400 gallons of condensate are required to remove decay heat and maintain the plant in hot standby conditions for four hours (see FSAR Table 10.4-2 and Figure 10.4-9, attached).
It should be noted that the capability exists to intertie the suction of the St. Lucie Unit 1 AFW pumps to the St. Lucie Unit 2 CST. St. Lucie Unit 2 FSAR Figure 10.4-8a (attached) provides the details for this intertie. The St. Lucie Unit 2 CST Technical Specification LCO includes 125,000 gallons of condensate reserved for St. Lucie Unit 1. This 125,000 gallons of condensate can be utilized to augment the St. Lucie Unit 1 CST volume to provide an orderly cool down to shutdown cooling entry conditions.
NRC UESTION Confirm that the AAC source will meet the criteria provided in Section 2.3.1, Appendix B, of NUMARC 87-00. Identify and discuss any exceptions to these criteria. In particular, discuss the single failure of 4160V Bus 3D or 4D. Also discuss single failure of 480V Load Center Bus 3H or 4H, in particular with respect to the battery chargers.
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FPL RESPONSEi St. Lucie nuclear site will provide a safety grade, class 1E, weather and seismically protected intertie between units. The intertie will allow each unit to be cross-connected in 10 minutes from the control room.
Per .NUMARC position letter dated January 4, 1990 which documents agreements met between NUMARC and the NRC, the intertie is defined as including the "swing buses" utilized to crosstie between units. This position letter also states that a single failure of the crosstie itself need not be postulated on the "non-blacked-out" unit. Therefore, the St.
Lucie AB swing buses, all AB bus supporting equipment (i.e.,
breakers, relays, etc.) and the interconnecting cable need not be considered for a single failure following a Station Blackout scenario initiation. Therefore, excluding the cross tie, no single failure of any emergency bus or emergency diesel or battery in the non-blacked-out unit will preclude mitigating the effects of a unit black-out on the blacked-out unit. The proposed intertie, as described, in FPL letter L-89-144, dated April 17, 1989 complies with NRC guidance and resolves this item for St. Lucie Units 1 and 2.
The criteria used to address SBO modifications shall conform with safety grade criteria applicable to the unit's current licensed design bases.
As discussed during the NRC audit, criteria applied to implement this design will meet or exceed the guidelines in NUMARC 87-00. Enclosure (5) to this response is FPL's comparison of Appendix B of NUNARC 87-00 to the St. Lucie proposed modification to resolve SBO.
NRC UESTION~
Confirm that the QA guidance contained in Regulatory Guide 1.155, Appendix A will be implemented for the AAC facilities.
FPL RESPONSE.
Quality Assurance (QA) guidance for St. Lucie station blackout modifications will be dictated by 10CFR50 Appendix B requirements under the current QA program at St. Lucie. This meets or exceeds criteria in Reg. Guide 1.155.
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~ NRC UESTXON'iscuss the proposed training program associated with station blackout scenario.
PPL RESPONSE FPL's training program for SBO will consist of:
- 1. Upgrading current. procedures to reflect system
.modifications to recover from a unit blackout, and
- 2. Training plant operators to these new procedures.
Currently, procedures and training are provided for both units for mitigating the effects of loss of all AC on one unit. The new 10 minute intertie will enhance and facilitate existing recovery actions.
Enclosure (6) to this response is the St. Lucie Unit 1 site procedures which are currently in use to address loss of all AC power.
- 8) NRC UESTXON:
Discuss the features of the proposed EDG reliability program, noting in particular the similarities and differences with respect to Appendix D of NUMARC 87-00.
PPL RESPONSE.
As presented during the Oct 17-19, 1989 SBO audit, the current FPL EDG reliability program is based on Quality improvements achieved from statistical quality control methods. The basic elements of FPL's program consist of the following:
a) problem identification and pareto analysis b) root cause analysis to include cause and effect diagrams c) 'onitoring parameters using statistical quality control techniques, and d) initiating corrective actions and countermeasures to improve EDG performance.
FPL is currently following industry and NRC initiatives for resolving B-56 EDG reliability. Based on our achievements on the St. Lucie Diesel Generator reliability program (Table 1) we believe that our statistical systems reliability approach provides the required high reliability without the need for accelerated testing. Following closure of the industry initiative on B-56, we will review the new guidance and, appropriate, make enhancements to our current program. Table if 1 provides the emergency diesel generator 'failures for the
1 last 20, 50, and 100 demands as requested by NRC auditors.
The data is based on information presented to INPO as of the end of September, 1989.
TABLE 1 FLORIDA POWER 6 LIGHT, EMERGENCY DIESEL GENERATOR FAILURES 2 0 DEMANDS lA-LUCIE ST 1 B 0 1 2 A 2 B
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50 DEMANDS. 1A- 2A- 1 1B-01 2 B 1 100 DEMANDS ~ 1A-3 1B-2 2 A 1 2 B 1
ENCLOSURE 1 FOR PPL RESPONSE TO NRC QUESTION (1)
,n NUREG/CR-4710 SAND86-1797 Shutdown Decay Heat Removal Analysis of a Combustion Engineering 2-Loop.
Pressurized Water Reactor Case Study Prepared by W. R. Cramond, D. M. Ericson, Jr., G. A. Sanders Sandia National Laboratories Prepared for U,S. Nuclear Regulatory Commission
Mind Hazard: St. Tucie is located on the east side of Florida on the Atlantic side of the peninsula. The site is located in Region I of the USNRC tornado risk regionalization scheme given in MASH-1300. This is the region which has the highest hazard of the three USNRC regions. The mean values of wind speed frequencies are as follows:
Tornado Strai ht Wind Mind Speed Mean Wind Speed Mean
~mich Value ~m)~h Valua 66 1.70E-4 80 2.18E-1 93 9.32E-S 90 1.01E-1 134 3.31E-5 111 2.00E-2 182 6.65E-6 120 1.00E-2 234 1.24E-6 128 S.OOE-3 290 2.03E-7 138 2.00E-3 349 2.50E-8 144 1.00E-3 150 5.52E-4 160 2.65E-4 174 1.00E-4 l97 'i?.OOE-5 207 1.00E-S 230 2.00E-6 240 1.00E-6
~e uence uantif ication: Based on the design and review criteria, all the plant Class I structures exposed to wind were designed for a hurricane wind velocity of 194 mph and the safety-related buildings and structures were designed to resist
+ tornado of 300 mph tangential wind velocity
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UPDATED REPORT PROBABILISTIC HURRICANE ANALYSES METHODOLOGY DEVELOPMENT ST. LUCIE AND TURKEY POINT NUCLEAR POWER PLANTS fOR FLORIDA POWER a LIGHT COMPANY JANUARY 1989 ames A PROFESSIONAL oore LIMITED PARTNERSHIP Job No. 4598-144-09 Atlanta, Georgia
7, TABLE 1 SUWARY OF MIRRICANE WINO SPEEDS AM) ASSOCIATED RETURN PERIlSS FOR TURKEY POINT AM) ST. LUCIE AS CALCULATED BY VARIOUS IKTNSS National Federal Eaergency National Hurrlcmm Center/Nemann Bureau of University of Hansgment Ageray/
Tr ical C lones )33 knots Welbul1 Stand ard s Western Ontario Omes 6 Noore Return Period Turkey Turkey Turkey Turkey Turkey
( ears) Point St. Lucis Point St. Lucis Point St. Lucis Point St. Lucle Point St. Lucis 100 94 73 70 80 119 115 87 79 200 110 103 78 75 130 129 300 117 111 80 77 400 122 116 82 78 500 126 120 83 80 89 800 133 127 85 82 1 e000 136 130 86 83 157 156 117 2,000 144 140 89 86 103 163 4,000 149 147 92 89 6,000 152 15D 93 90 8,000 153 151 94 91 10,000 153 153 95 92 20,000 155 154 97 95 40,000 156 156 100 97 80,000 157 157 102 99 100,000 157 157 102 99 144 144 1,000,000 157 157 108 105 152 153 O
Zl Wind speeds ln knots representing 10-aeter, 10-ainute values.
Tl All wird speeds iralude the translational wird speeds.
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GRID CAPABILITY RELATED TO SBO
~ DESCRIPTION OF FPL'S TRANSMISSION SYSTEM 0 FPL PROCEDURES
~ ACTIONS TO INSURE OFFSITE POWER SECURITY ANALYSIS 5r'17i'85 SOUTH FLORIDA BLACKOUT 8i20/89 SEPERATION FROM INTERCONNECTION 0
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To provide gufdeH~ tor system restoratfon trom a blaelaxtt where a portion ot the power system fs stf11 connected to the interconnected system Blackout - h condition where a ma)oc portion, perhaps all, ot an electrical utfHty system fs ~ergixed with much of the system tied together through closed breaker.
Step by step 1aM aepmme - h controlled sectionaHzing ot the transmission gtfd and a sequential reenergiaation ot the bulk stations starting from the energfred system and moving through the blackout area.
P~ ~ng e - The mN loading required to eHminate the capacitance effect off the line (on a line with no tafyed load the mN loading whete VhRS fn ~ YhRS Out).
Qeamallnstruetfae 1. Inform the Divfsion Load Dfspatchers ot blackout and instruct them mt to epee any Hnes until the bumdarfes ot the blackout area have been determined.
2 Decide on a plan of restoration bearing in mind .the tollowlng m
effete power to the nuclear plants it at ail
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Maintain poasfhle. If the nuclear plants have lost otf-site power, restore it as quickly as possible. h restoration ot 10 minutes or 1~ fs considered a prompt recovery.
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bo Restore start~ power to all available generating units.
Units still running, but carrying only their own auziHary h a stabiiil;ed and fs teady.
In restorhg start~ power to a unft in a black out eaxftfon (unit dfd not stay on Ns own auxfHary trans-
.gS formers the restoratfoa must be done in such a way that the plant auxlHary buses are not energiij;ed without plant
)It operatfng personnel amurfng that no equipment fs unduly ectmeeted to the auxQhry bus. Pafiure to do this may
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- once Ofi tfHed transmfssfon pipe cables can be re-energfxed at if they have not gone over 30 minutes without the pumps ruimflg or without being energfxed.
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System Restoration To provide instructions for restoring of! site power to Nuclear Plants when all oft site power has been interrupted.
The highest priority is assigned to minimize the time that any Nuclear Plant is without adequate off site power. h prompt recovery (10 minutes or less) is a desirable goaL Restoration ot 1. Prepare the Nuclear Plant for restoration of off site power Ott-site Power without back feeding out ot the plant.
- 2. Determine the moat available energized buL
- 3. Clear the necessary circuits between the energized bus and the Nuclear Plant.
- 4. hs much as possible the switching for concurrently.
clear is to be carried on
- 5. Once there is an energized bus at the Nuclear Plant verify that the voltage is within emergency limits betore energizing the start Up tM!lstormere
- 8. ha soon as possible provide at hest two feeds to the start up traretormer.
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NR 31 1989 10&1 2 lOH Rmtoratha ot ON Qte Pea<< to Nmiear Pleats - 'hay Pent Plant To provide guidelines for restoring off site pow'er to Turkey Point Plant.
Pour general plans are developed using each of the three 240kV Uncs and the SOOkY line feeding into Dade County from the KD North, plus three of the 240kY lines feeding into Turkey Point R~g~gO~
~O Plan/ with back feed of the Turkey Point-Plagami 01 240kV circuit.
Restoring Po~ to Tiakey Point-Geaaal site power to Turkey o t. The mos whi e y arer gal~off
- Levee 500kV
- Port Hvetglades 230kV
- Laxlerdale 230kV If these lxmes are ~erghed,'determine the avaQable ener-gise4 bunce that are Arrther north and determine the plan to Eolhnr to cee of the above buses from the intercon-nected system Aesedrro 01$ 80I) and notify the appropriate Division Dispatcher. ha soon as the minimum necessary clearing switching has been eomplet~ give instructions to the Division Dispatcher to eaergise eireuits to restore oft site power.
If mergi3ed buaer are not readGy available, order Black Start-pa~ I~~Q Qae 'i~ines 0 Pteesdae 01601L1) and Black itaet - Poet Sreriiar5ee Qas%etdm QO Ptoeedrae 018610M).
Nhea use Black Start to provide off site power it is desirable
~ yO to have on line before starting to
~ nergise 2 k ts into Dade ty.
to Point Plant ference is to dree are to .eonsi the o w orderr
- Port Hveqgades North 234kV '
- Lauderdale East 234kV.
Rrdytown South 540kV hs soon as the minimum necessary clearing switching has been completed, give instructions to energiie circuits to restore off site power to Turkey Point Plant.
Page 1 of 11
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QN 31%9 18801.1 SUVJE 0 Restorat5m eC Off Qte Poem-
'SL Lu5e Plant To provide guidelines to restore off site power to St. Lucia Plant.
Restoring Of flite gyve Power to St Lucie- OUZO~
General System 1. Determine the avaGable energhed busses which could supply off Operator site powei. The moat likely ares
- Midway 230kV
- Pofnsett 230kV
- Cctbett 230kV
- 2. Determine the appropriate plan to foHow and notify the Eastern Dfvfsfon Dispatcher and ff appropriate the Northern Dfvfsion Dfsyatcher.
lf necessary more than one plan can be fn operation at the same time.
- 3. As sooa aa the mfnfmum necessary switching for clearing has been completed give the instructfae to energize circuits to restore off site power to St. Lucfe Plant.
4 Upon recefpt eC fnetructiaa from the System Operator or without hettuctfona ff it fa fumwn that all off sfte power has been lost at St. Lucfe Plant and Midway, prepare St. Lucfe Plant fee restoring otf site power without back feeding out of the phatic At St. Lucfe Plant Station 403) open aH 230kV breakers.
Oyaa m eheak to be eyes the fdlowfng breakerss SN20 Unit No 1 SN30 SN33 Line No 1 SNSS Start up IA 4 2A SN40 Slf43 Lfne No 2 SN49 SN$ 2 Unit No t SNSI Line No 3 SN51 8%84 tart ~ IB 4 2B SPfd7 Hutchfreon hland,Mfd Breaker
8yetem Oyeeatkes ~~< JUL 3g 1982 16810 SUOJECT SCCTIOH 0, To provide guidelInes for r~nergizlng portions of the area of blackout from plants which have "Black Start capability.
General Energize transmission circuits with few substations to minimize Considerations load pick up.
Pick up radial load areas while maintaining the ability to synchro-nize the generator area" to energized high voltage transmission system acroas a breaker at the generation plant.
Do not try to maintain a close tolerance on 80 Hz operation.
Operation between 59.0 and 61.0 Hz should be satisfactory.
In reenergizing portions of the blacked out system from isolated generation try to limit the frequency dip to a maximum of 0.2Hz on each step of load pick up (a step load pick up of approximately 6.5% of generation capacity of units on line in the Isolated area).
When possible, tie generation areas together to increase the amount of generation available to pick up load and thus minimize frequency variations.
odlÃ'cs Lauderdale Gas Turbines Procedure t16610.1 yi Port Everglades Gas Turbines Procedure f16610.2.
Ppl'4 Page 1 of 1
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0 SECURITY ANALYSIS PURPOSE: TO EVALUATE FPL'S TRANSMISSION SYSTEM FOR THE SINGLE CONTINGENCY LOSS- OF A TRANSMISSION LINE OR GENERATOR
~ IDENTIFIES OVERLOAD CONDITIONS
~ GUIDES THE OPERATOR IN RELIEVING OVERLOAD e ~
CONDITIONS USED TO SIMULATE HYPOTHETICAL CONDITIONS TO EVALUATE FUTURE GRANTING OF CLEARANCES
~ TIME FRAME: RUNS EVERY 15 MINUTES
REPORT SYSTEh4 DISTURBhNCE MhY 17~ 19K I
POSER SUPPLY TECHNICAL SERVICES PLOiQDh POSER 4 LIQHY COMPhNY
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SUMMARY
On Friday, May 17, l98f, at approximately 11:07AM an area extending from South of West Palm Beach to Florida City along the east coast experienced a power outage. A fire raging out of control in the transmission corridor tVorth of Andytown substation took out of service the three f00kV transmission lines feeding power into the South Florida area. The remaining transmission into the area was disconnected South of Ranch substation by protective relays. Available generation, unable to supply the load in the areag was removed from service by its protective equipment. The Northern and Western areas of the FPL system were not affected.
With the realization that a blackout condition existed, the System Operators began preparing 'for restoration.
desi nated restoration uidelinese minutes.
T Po'o, h connection between the energized system to the North and the affected area was established through the Lauderdale switchyard.
Off-site wer was then made available to This rocess took a oximatel f ur g thm same t e, a systems c process ot restoring power to other
-four Plants in tha affected ar~ Port Everglades and Lauderdalev was undertaken Customer restoration proceeded as rapidly as possible.
With the f00kV lines still out of servicep due to the fire, load pickup was limited by the thermal capability of the underlying transmission system and available gas turbine generatim in the affected area. The two Andytown-Martin 500kV lines were reenergized at 2if6PM after the fire had died out and customer restoration proceeded rapidly from that point. Sy 3!20Ph4 the system load had reached its pre-disturbance value of approximately NOOMW with only isolated customers still to be restorede There was no identified equipment damage resuiting from this incident.
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RESTORATION OF SERVICE With the realization that a blackout condition cxistcd, the System Operators began preparing for service restoration. The process, as detailed in Appendix F, can bc divided into three parte A - Restoration of start-up power to the power plants in thc affected area; B - Restoration of the bulk transmission system~ C - Restoration of the load-serving lines.
A.- Restoration of Start- u Power to the Plants Priori was laced on rcstor the off-site wer T Point P To accomplish th~ a connection between the energized system to the No was established through the Lauderdale switchyard Next the Port Everglades bus was energized, followed by the Flagami bus T t was cncr ized at F -T 5t rt u sformcr was dela ed for 15 minutes b an rabl mid-brcakcr. At a roximatel 1201!27 off-site wer was restor to T 't No. 0 tf -f m ter init ti of the blackout
~nditLoO, Simultaneously, start~ power was being restored to Port Everglades and Lauderdale plants. The Lauderdale Qas Turbine Site No 2 was energized at 12!01<f0. Port Evetglades Qas Turbine Site was energized at 12>00tf8. Port Everglades Start~ transformer was energized at 1286<36. Lauderdale Gas Turbine 51te No 1 was energized at 12>1701 and the Start-up transformer was energized at 12!20I3f. Start~ power to Units!Co. 1 and No. 2 at Turkey Point was restored at 1202>N. Start~ power to Unit No. 3f down for rcfucllngj was rcstorcd at 13>f 3!2$ .
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OPERA,'1/Gi'a o.~ dtJNANDUIyIS TRhNSMISSION OPBRhTING P ROC BD U RES
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STATISTICAL S,.vlCE TDO- General Office (tf(OM: We H Cole ~ma July 18, 1985 suaicr: PIRES NEAR TRANSMISSION RIO~P-PfhYS coP(esto: J. W. Hart h J. Olfvera
'T. Utspruch W Dfvfsfon Th D hfanagers As we dfscussed at our recent Transmission Supervisors Meetfngp recording of information relative to fires near our Transmission Right-of-Ways is quite important and especially so for our 500 kV Cfrcufts.
The following consideratins are offered for a Gufdeffne should the occassfon arise of a fire near our Transmission Rfghtwf-Ways'.
Foremost in our planning shouM be a p~m respoIIse when notified of a tire on or near our Transmission Rfghtwf-Pfays.
IL 'lhe first employee on the scene shouM make a rapfd assessment of the pesslhle dsdree o( jespordy to the t?ansmlsston Clrutt(ah al '(he Division Dispatcher needs to know immediately tl the elreult ls fn danger and ff not fn fmmedfate daiger, an estimation of future extern How Iongt Be sure to report Lhe Name, Structure 4 and lsocatfon ot fire wftll re+Not to circuits fete Bf Wf Nf Sf etc.
b) To determine how longf several important facts are required:
I) Is fire moving toward Right-of-Way or along Rfghtwf-Ways
- 2) What fs between Fire and Rfghtmf-Ways What type vegetatfont Will it burn fast or slows
- 3) Are there any canals, roads or other obstructfons between Fire and Rfghtwf-Way.
- 4) Make an estimate of time fire might reach Rfghtwf-Way.
c) 8 there a possfbQfty of the Right-of-Way itself burning T 4 SmouJd addftfonal help be requfredT If sof request that appropriate crews be sent to scene.
e) Stay near vehicle or at least k in.'communication with the Division Dispatcher.
ill. Remain on the scene until released b the Division atch PEOPLE... SERVINQ PEOPLE E forrrt 1400 (5tocnedt ster. '..d:
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IYITIXOtIRATIONS XEXOkhNDUg TRhNSXL54ION OtII.ATING tROCEDVRES 2,1.4C tsriaaeaiCI cceymomISca Memo Book Holders ueavloss PSO/LF0 ShOM: C. M. Mcnncs ops: July 5, 1988 sULlscri ST. LQCIB/MIDVhY ccwlss To:
TRANSMISSION ChPhCITY 1 fifth tro St. Lucfe Units on lfne and total plant output fn cxccss of 1000M%:
- d. Twn St. Lucia/Midway circuits in tarvice Notify the plant personnel that the transmission fs fn a state ot alert. The plant fs to be advised ot the requirements of having only one line.
- 8. One St. Lucie/Midway circuit le eervice
- 1. Vest Palm Beach temperature ts 80'P or higher. Reduce plant output belor 1000XV rithfn 4 mfnutes. (This ~ma require trippfng one unit att fine)
- 2. Vest Palm Beach temperature fa belor 80~P. Reduce plant output befor 1100XV rithfn 8 minutes. (Thfs ~ma require tripping one unit ott line) fI Vfth me St. Lucie Unit an finer
- h. Tro St. Lucfe/Xfdray circuits fn service Notfty plant personnel that there fs one line out ot service.
B. One St. Lucfe/Xfdray circuit fn service Notfty plant personnel that the transmtssfon fs fn a state at a1ert. There fs suttfcfent transmission capacity to get thc porer out ot the plant. The plant personnel rill have to decide ft this line provides adequate ott site porer to keep the onc unit on line.
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Diaturbanco Report Separation and Electrical Ialanding of Peninsular Plorida August 20, i989 Prepared by Power Supply Technical Services
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On ~ 20, load shedding took place. Approximately y 1 1F~.,
Florida separated from George'IL. Polloving the separation, undorfrequency 70 vo e vithin tho isolated area, including 1,576 HW in PPL's service territory. At tho time of tho disturbance, FPL load and generation vore 10,421 and 7,243 MW respectively. Not interchange vas -3,725 HW including Seminole load replacement schedule. Southern Co. imports vore 3,136 HW into tho state.
Tho sequence of events loading to tho separation started vith tho failure of Georgia Povor (GAP) svitch No. 766, utilized to connect shunt reactors to tho Duval-Hatch 500 kV line, at Hatch Plant (GAP), Figure 1. A phase to phase (A-B) fault occurred after tho svitch vas opened. As a result of tho fault, the Duval-Hatch 500kV line tripped, follovod by an incorrect trip of tho Duval-Thalman 500kV terminal at Duval, vhich reclosed 27 cycles later. By thon tho Kingsland ond of tho Duval-Kingsland 230kV line had sensed an out-of-stop condition and tripped at Kingsland. Approximately 62 cycles after tho Duval-Thalman 500kV, line tripped-roclosed at-Duval, tho line tripped at Thalman on zone 2 of tho backup distance relay. Subsequent to this action protective relay action at Columbia and Pt. White isolated peninsular Plorida. The cause of the rel'ay misoporation on tho Duval-Thalman 500kV line at Duval is under investigation..
Folloving the separation, the frequency dropped to 59.37 Hz, initiating undorfreqaoncy load shedding throughout tho islanded area. The folloving load shedding vas reported by PPL and other utilities.
PPL 1576 MW PMP 119 MW FPC 500 MW QVL 28 HW HST 7 MW JXh 275 MW KIS 7 MW LAX'WV 30 MW 7 MW OUC 60 MW SIB 5 MW SIC 79 HW STC 9 MW STK 2 HW TCC 260 MW VER 2970 HW
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PPL did experience soeo high voltages, on tho order of 10 but automatic controllers switched reactive devices to maintain tho voltage. Approximately 746 HVAR of reactive compensation was obtained froa static var sources, both transaisaion and distribution and 1330 from synchronous sources (generators), a total of 2076 MVAR.
Approximately twenty (20) seconds after tho fault, Ft. White roclosod, ro-connoc ting peninsular P lorida. At around 4: 14 p.m., 'oor gia Poser closed tho Duval 500kV line at Thalman. FPL thon instructed other utilities to proceed with the restoration of customer load. Combustion turbines vore dispatched and PPL yrocoodod vith load restoration (4:21 p.m.). All load was restored by 5:17 p.m. At 7:51 y.m., the Duval-Hatch 500kV line was returned to service.
ENCLOSURE 2 FOR,FPL RESPONSE TO NRC QUESTXON (2)
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REG GUIDE TABLE 5 OPFSITE POWER GROUP OPG I2 CATEGORY 2A DISCUSSION "Automatic and Manual transfer schemes for the Class 1E buses when the normal source of AC ower fails and when the backu sources of offsite ower fail."
For the St. Lucie design the normal source of AC power is assumed to be the unit main generator as fed through the auxiliary transformers to the Class 1E buses.
As depicted in the one-line diagram of Figure 1, each St. Lucie Unit receives its "normal AC power" from two (2) dedicated auxiliary transformers (UAT). One (1) A-train and one (1) B-train auxiliary transformer are utilized for each unit.
Upon loss of this normal source on one unit through causes such as loss of the main generator (G1 or G2), the main transformer group (MTI or MT2), both auxiliary transformers or the main generator output circuit to the switchyard, an automatic fast-transfer occurs to the A and B train start-up transformers (ST1 or ST2) of the affected unit. The A train and B train start-up transformers receive their power from independent circuits leading into the switchyard.
This exceeds the criteria for the automatic transfer for OPG I2 Category 2.a. which states "after loss of the normal AC power source, there is an automatic transfer of all safe-shutdown buses to one preferred alternate power source". This provides two independent sources of separate preferred alternate power which are automatically transferred.
For the St. Lucie design there is an additional preferred alternate power supply available. The source requires a manual transfer via the non-affected units start-up transformer and/or main generator.
The St. Lucie Plant manual transfer schemes meet the OPG I2 Cagegory 2.a. criteria described above by the following:
- 1) Loss of one (1) start-up transformer on the affected unit leaves a manual transfer (2A4 or 2B4) available to the opposite unit's start-up transformer of the same train.
This manual transfer can be accomplished in 30 minutes.
Therefore, both A and B train Class IE busses remain fed from offsite power.
- 2) Loss of the circuit to the switchyard caused by a fault in the line itself, a fault on the bus between the two switchyard breaker will cause the loss of power to both start-up transformers of one train A or B (i.e. both 1B and 2B, or lA and 2A start-up transformers would be lost). Power can be provided to energize the second train of Class lE buses through the existing manual transfer -buses 2A4 or 2B4 from the opposite units auxiliary transformer.
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The addition of the safety grade, class IE, unit intertie will provide a redundant means to power a safety grade electrical bus which has lost all power sources.
NUMARC 87-00 page 3-11 states that "the off-site power system is in the I3 group if: (1) a yes answer can be assigned to condition "A" below, and (2) a "yes" can be assigned to either conditions "B(1)" or "B(2)," below."
The answer to condition A, "all off-site power sources are connected to the unit's safe shutdown buses through (1) one switchyard, or (2) two or more electrically connected switchyards," is "Yes." However, the answer to condition B(1), "The normal source of AC power is from the unit main generator and there are no automatic transfers and one or more manual transfers......", is "no," since there are two independent concurrent automatic transfers. The answer to condition B(2) "The normal source of AC power is from the unit main generator and there is one automatic transfer and no manual transfers of all safe shutdown buses to one preferred or one alternate off-site power source", is "no", since there are two independent automatic transfers of the shutdown buses to two separate preferred off-site power sources. Page 3-11 continues: "Otherwise the site is assigned to the ~X 1 2 group."
Therefore FPL has concluded that St. Lucie is in the I 1/2 group via NUMARC 87-00 page 3-11 and is further classified as Offsite Power Group I2 by Reg. Guide 1.155 table 5.
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- l. AQ offsite power sources are l.a. AQ offsitc power sources are connected to the connected to thc plant plant thtough one switchyatd.
through two or mote ewitchyards or separate OR incoming transmission
- l. lndepcndencc of offsite Lines, but at least one of !.b. AQ offsite powet soutccs are connected to the powcf soufccs the ac sources is clectricaQy pLant thtough two or mote switchyatds, and hdcpcndcnt of the otherL the switchyards are elcctricaQy connected.
(The inde pendent 694Y (The 34S. and 138 kV switchyards in Figures Line in Figure 1 is 2 and 3 represent this design feature.)
representative of this design feature.)
- 2. Automatic and manual 2 L Af'tcf loca of thc normal ac 2.L After Loss of thc normal 2.L lf the normal transfer schemes for thc sourccI ac power source, there is source of ac CLass lE buses when thc an automatic transfer ot power faQs, thefe normal source of ac powct (1) There is an automatic aQ saf~utdown buses ate no automauc faQs and when the back- transfer of aQ safe. to one preferred alter- transfers and up sources of offsitc shutdown buses to nate power source. lf onc or more power faiL a separate preferred this source faQs, there manual transfers alternate power source. may be one or more of aQ safcWut.
L Thc normal source of manual transfers of down buses ac powet is assumed (1) There !s an automatic power source to the to preferred or to bc thc unit main transfer of aU safe- . remaining preferred alternate off-generator. shutdown buses to onc or alternate offsite citc powct preferred power source. po wcf soutccL soufccL lfthis prefened powet source fails, there is OR another automatic transfer to the Theta is onc auto.
remaining metic transfer preferred power and no manual
~ ourccs or to alter- transfer of aQ nate offsite power saf~utdown buses to one preferred or onc alternate oftsite power OR OR
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- b. lf thc Class LE buses 2.b. Each saf~utdown bus!a .b. Tbc safe&utdown buses ire hormaQy aLigned are normally designed IsittsaQy connected to ~ to thc same preferred poller source with to bc connected to tbc separate preferred alter. either an automatic ot mdnug transfer to thc prefcned or alternate nate power source <<ith remaining preferred or alsetnate ac power powef sourccL automatic or manual I transfer capabQity % 0 ~ o ~
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8-2 2 ANALYSIS 8,2.2 1 Switch ard and Crid The requirements of Ccneral Design Criterion L>, "Electric Po~er Systems",
are s~tisficd by tbe foLloving:
- 1) '[bc network interconnections consist of three transmission ines ~ Any 1
circuit may be interrupted with the remaining two circuits being con-chie of carrying the fuLL output of the station.
- 2) Although the switchyard is common to all thrcc lines, each line ter-minates in a separate bay and can be connected to either of two sepa-rate buses Failure of one bus or of the equipment in one bay does not resuLt in loss of more than one line.
- 3) A single brcakcr failing to trip does not result in failure of both Lines because there arc aLvays at least tvo brcakcrs in series be-tvcen the tvo lines.
- 4) Thc three single 240 kV lines crossing the Indian River are designed to vithstand hurricane vinds of 153 mph; the Lines vest of thc river arc designed for vinds of 140 mph ~ Mith a spacing of 200 ft betveen ~
the river to~era, 174 ft. above mean sea Level, and a spacinF of 126 ft. betveen the 80 ft. high towers on land, the faiLure nr col-Lapse of one structure does not affect tbe other lines-5; The 240 kV system is protected from Lightning and switching surges by overhead electrostatic shield vire and surge protection cquipmcnt.
- 6) Tbc svitcbing arrangement in the 240 'kV svitchyard includes two Full capacity main buses vbich are tied to the generator, startup trans-formers and outgoing transmission Lines through circuit breakers con-nected to each busi Protective features provide reliable protection
<or isoLation of faults to ensure continuity of power supply from al-ternate sources The protective relay system includes hish speed primary and backup relaying. Primary reLaying consists of carrier re-laying utiliaing phase and ground distance relaysi Backup relaying consists of phase and ground distance relays as veil as backup protec-tion for breaker failure to trip. A secondary, high speed relaying system, consisting of carrier relaying phase and ground distance re-lays is being added to each ot the three 240 kV lines. Primary and backup bus differential relaying ia also provided. These provisions permit the folloving:
(~ ) Any circuit can be svitched under normaL conditions vithout affecting another circuit.
(b) Any single circuit breaker can be isolated for maintenance vithout interrupting the pover or protection to any circuit.
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(c) Short circuits in a single main bua are isolated without interrupting service to any circuiC.
(d) Shore circuit failure of ~ single bay breaker does not re-sult in the permanent loss of any transmission line or any startup transformer.
(c) Physical independence of pover and controls for the start-up transformers is achieved by segregating the avitchyard into tvo systems. Each system, consisting of oil circuiC brcakcrs, bua differential relaying and associated equip-mcnt, is linked to one of the pairs ot'tartup transformers.
panels The cabling of the tvo svitchyard systems are either separated or separated by fire barriers except at equipment spatially control .
S.2.2.2 Transmission Lines and In-Plant E ui ment The requirements of General Design Criterion 17, are satisfied by the fol-loving:
a) Two physically independent circuits are provided for offsite pover. hlthough in the same right of way, the tvo lines are spaced sufficiently far apart that a failing transmission tower cannot involve the other line.
b) All circuits are normally cnergiaed ao that eitl er is availsblc immediately to provide sufficient pover to assure that tuel design and reactor coolant pressure design limits are not exceeded, assum-ing loss of all onaite pover.
c) The transformers asaociaCed vith Che Offsite Pover System are provide<with a Fire Protection System. They are located suf-ficiently Ear apart so as to prevent any damage ChaC may occur in one transformer from occurring in any other transformers Tvo generator transformers when paralleled on both HV and LV sides, comprise in effect a single unit ~ A three hour rated fire wall is used to separate these tvo transformers rather than distance a lone.
The two transmission lines are electrically separated by at least tvo circuiC breakers in series, at the svitchyardi Two breakers vould have to fail to trip in order for a fault in one line to involve the other.
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8.3.!.2 A~nal sls Class [E electric components are designed I:o insure I:hat any of t: he design evenrs lisred in lt EE 308-1971 do nor. prevent operation of rhe minimum numocr of'safery-rclaced loads and prot:ective devices that: would be re-quired ro mit:igare rhe consequences of an accidenr. and/or safely shurdown rhe reacror.
The General Design Ctireria are covered in Sect'ion 3.1. The following design aspect:s illust:rare t: he extent: of conformance with respecr. ro Rcgu" larory Guides, lEEE Srandards, and General Design Criteria (GDC).
- 8. 3. 1. 2. 1 General Design Cri t:er ia General Desi n Criterion 17 Redundancy of t: he emergency auxiliary power syst:cm is provided for rhe operation of redundant safety relat:ed electrical load groups. This redundancy cxrends from the emergency power source, through 4.16 kV buscS, sf:al:ion service t:ransformers, 480 volt buses, MCCs, distribution cables, 120V/208V and 120V panels, invert:ers, and protective devices.
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Eacn of rhe redundant onsit:c emergency power sources and associated load groups i niependcnt ly provide for safe shutdown of the plant and/or mit:i-arion of rhe consequences of a design basis accident..
ENCLOSURE 3 POR PPL RESPONSE TO NRC QUESTION (3)
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