ELV-03551, Forwards Response to NRC 920220 Safety Evaluation & Recommendations for Plant Station Blackout Coping Analysis. Plans & Schedule for Implementing Recommendations or Justification Why Recommended Action Not Required Also Encl

Forwards Response to NRC 920220 Safety Evaluation & Recommendations for Plant Station Blackout Coping Analysis. Plans & Schedule for Implementing Recommendations or Justification Why Recommended Action Not Required Also Encl

ML20094M420
Person / Time
Site:	Vogtle
Issue date:	03/26/1992
From:	Mccoy C GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ELV-03551, ELV-3551, TAC-M68621, TAC-M73447, NUDOCS 9203310217
Download: ML20094M420 (9)

Text

. .

c., . w r . -. , c m a . ,

N.l. [.[l7 "'

t;l'M ,'IM "

n c.A.uccoy GeorgitiPower

[,j]..'"7" <4 m-- .c ,

11 arch 20,1992 Lty.03551 001325 Docket Nos. 50 424 50-425 TAC h68621 M73447 U. S. Nuclear Regulatory Comission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

V0GTLE ELECTRIC GENERATING PLAN 1 REPLY TO NRC SAFETY EVALUATION AND RECOMMENDATIONS FOR VEGP STATION BtACKOUT COPING ANAL 111]i Georgia Power Company (GPC) letters ELV 00432, ELV 01474, and ELV-02867, dated A)ril 12,1989, March 28,1990, and June 7, 1991, transmitted GPC's response to tie station blackout (S80) rule for Vogtle Electric Generating Plant (VEGP). On February 20, 1992, the NRC staff issued its safety evaluation (SC) for that response. In the SE, the NRC staff stated that VEGP's proposed method of coping with a station blackout (SBO) conforms to the SB0 rule, subject to the satisfactory resolution of certain items. The attachment to this letter addresses each SE item of concern and provides our plans and schedule for implementing your recommendations or the justification why the recommended action is not required.

Please contact us if you have any questions or need further information regarding this matter.

Sincerely.

$1f ' '

0C. K. McCoy '

j CKM/AFS/gmb /

At t ac ht,'.ent : Reply to NRC SE for VEGP SB0 Coping Analysis xc: Georaia Power Comoany Mr. W. B. Shipman Mr. M. Sheibani NORMS U. S. Nuclear Regglatory Commision Mr. S. D. Ebneter, Regional Administrator l

Mr. D. S. Hood, Licensing Project Manager, NRR gh-Mr. B. R. Bonser, Senior Resident inspector, Vogtle .

j[j33[$$ck0 0 4 L J

ATTACHMENT V0GTLE ELECTRIC CENERAllNG PLANT REPLY .10_SE FOR STAT 10N BLM1QQ1 2.2.2 CLASS _lE BATTERY (APACITY Staff Evalwltion of_ licensee RESE2H11'1 The review of the battery sizing calculations for SB0 loads provided by the licensee reveals the following concerns:

1. The licensee needs to verify that the battery room tem 3erature of 700F as used in the battery capacity calculations is tie lowest anticipated electrolyte temperature during normal operation per NUMARC 87-00, Section 7.2.2.

2. The licensee did not consider any design margin (10 percent to 15 percent per IEEE Ltd. 485) in its battery capacity calculation.

3. The inverter 100114 full lead efficiency of 74.5 percent as used in the calculation is non conservative since the load is 80 percent of the rating.

4. The no load loss of 1800W for 25KVA inverters (100115 and 10D116) is non conservative.

Based on the above, the staff cannot conclude on the adequacy of the battery capacity.

EECpmmqpig11gjl1 The licensee needs to re-evaluate the battery capacity considering the above concerns. The battery capacity verification and any resulting modification should be included in the documentation that is to be maintained by the licensee in support of the 500 submittals.

Reinsfis.1 With the information provided below which addresses the four specific concerns about SB0 battery sizing calculations, VEGP is c.onfident the batteries meet the requirements for coping with a 4-hour station blackout without requiring any modifications or load stripping.

1. Per VEGP Technical Specification section 4.8.2.1.b battery electrolyte temperatures are nionitored to ensure that electrolyte temperatures do not fall below 700F during normal plant operation.

In addition, the daily control building operator surveillance rounds verify that the temperature for the class IE battery rooms is not below 700f during normal plant operation.

1

ATTACH!iENT (C0t411NUED)

V0GTLE ELECTRIC GENERATING PLANT REPLY 10 SLJAR_11A110N Bt ACK0VI 2.2.2 CLASS lE BATTERY CAPACITY Response (contimteni

2. Additional design margins as recommended in IEEE Standard 485 were not factored into the 580 battery sizing calculation because the SB0 battery profiles as current'y modeled in conjunction with the applied IEEE methodology are conservative. As an example, the loads fed from the Class 10 inverters used in the calculation are at least 40-percent greater than the actual field loads recorded at i VEGP Units 1 and 2 during 100 percent power operation. The actual 100-percent power inverter load is a good representative inverter load for SB0 conditions. If actual inverter load currents recorded during 100 percent unit power operation, were used in the calculation, it would show that design margins in excess of 10 aercent are available. Design margin is used in initial plant aattery design calculations, and is applied to compensate for load expansion, temperature, and maintenance factors. Additionally, temperature correction factors are independently accounted for in the SB0 battery sizing calculation. The SB0 battery sizing calculations will be revised by february 1993 to document these justifications as the basis for not using the IEEE-recommended ,

design margins and to incorporate changes outlined in 3 and 4 below. Also, note that as currently stated in the 500 battery sizing calculation, all future load additions will be evaluated against this calculation to determine acceptability of the <

modification.

3. The calculation will be revised to account for an inverter efficiency commensurate with an 80 percent load for inverter ,

1D0114. This small additional load, however, will not preclude the battery from performing its intended SB0 design function.

4. The no load loss of 1800 W for 25-kVA inverters (1C0115 and-IDDl!6) will be deleted from the SB0 battery calculation because these inverters are secured by locking open their corresponding feeder ,

breakers during normal plant operation. Administrative controls 1 are in place during normal plant operatinn to ensure that these inverters 'and their loads (residual heat removal isolation valves) are deenergized, i

r 2-l l

i l

A1TAtletENT (*0NTINUED)

V0GTLE ELECTRIC GENERATING PLANT reply 10 SE FOR $1AUgWM@yl 2.2.4 EffECTLOf LOSS Of VENTILAUM itsff Evaluation of Licenne_Rurmttet With the exception of the calculated temperature (1190f) for the control building inverter and switchgear rooms, the calculated temperatures for all areas are within the acceptance limits described in NUMARC 87-00 for the equipment required to cope with an SB0 event.

The licensee used the normal room temperature as the initial temperatures for the control building inverter and switchgear rooms heat up calculations. The staff finds that the licensee should either use as an initial temperature the maximum allowed by TS or the maximum value allowed under administrative procedures. If the licensee's administrative procedures do not specify an operating temperature limit, the licensee should revise their administrative procedures to maintain the normal operating temperatures in these areas at or below the value used in their SB0 heat up analysis.

The licensee has not addressed the containment temperature during an ,

SB0 event and the 500 equipment operability inside the containment.

RecommendAttons:.

The licensee should verify that the containment temperature profile during an SB0 event is bounded by that of the LOCA/High Energy Line Break temperature profile. This verification should be included with other dccumentation that is to be maintained by the licensee in support of the SB0 submittals. The licensee should use an initial temperature for the SB0 control building coniplex heat-up calculation no lower than that allowed by the TS or the administrative procedures.

Resoonser Given the information arovided below, VEGP SB0 coping equipment can be reasonably assured to )e operational during the 4-hour coping duration with respect to the effects of loss of ventilation.

Containment Temperature:

Based on a review of VEGP normal containment heat loads, anticipated SB0 heat loads, and the loss of coolant accident (LOCA)/high energy line break accident (HELBA) heat loads, it was determine! that the containment SB0 environment would be enveloped by the LOCA/HELBA environment. Since all safety-related containment equipment-is quallfled to VEGP's design bases LOCA/HELBA environment, containment equipment will not be adversely affected by the SB0 containment environment.

m . _ _ . _ - . . . . _ . . . _ _ . _ _ . _ _ - - _ _ _ _ _ _ _ _ . - _ _ _ _ _ . _ _ _

A1TACHMENT (CONTINUED)

V0GTLE ELECTRIC GENERATING PLANT REPLY 10 SE FOR STATION.JMZQQl Control Building Complex float Up Calculations: l l

E.WRC 87 00, section 7.2.4, " Effects of loss of Ventilation," l states that the upper bounds for wall temperatures should be determined prior to loss of ventilation, in performing the VEGP SB0 heat up calculations, all upper bound wall j temperatures utilized were the VEGP design bases normal  :

I maximum room temperatures. At VEGP the normal maximum room temperatures are those temperatures which would not be i exceeded when all normal heating, ventilation, and ,

air condi'.ioning (llVAC) is in operation, and the normal design maximum outside ambient conditions, maximum cooling water temperatures, maximum equipment heat loads, etc., exist. _As recommended by NUMARC 87 00, VEGP used the highest calculated normal ambient room temperatures, at the onset of the loss of ventilation, to calculate the final SB0 room temperatures.

This methodology provides reasonable assurance that calculated SB0 mar.imum average ambient temperature will not be exceeded.

2.2.5 CMIAllLMENT ISOLATION Staff Evaluation of Liernseo Response:

The licensee stated that the plant list of containment isolation valves '

(CIVs) had been reviewed to verify that valves which must be capable of being closed or that mus, be operated (cycled) under SB0 conditions can be positioned (with indication) independent of the preferred and blacked out unit's Class IE power supplies. The licensee further stated that no plant modifications or procedure changes are recuired to ensure appropriate containment integrity under SB0 concitions.

Based on its review of SAIC's TER and the list of CIVs provided by the licensee, the staff concurs with the SAIC TER that with the exception of the excess letdown and sealwater line penetration (X 49), the containment isolation valve design and operativa at Vogtle plant have met the intent of the guidances described in RG 1.155.

l 4

__. ._ _ _ _ _ _ _..._.._.____._.-_._._._._m.,

4 A11ACitMLNT (CONilNU[D)

V0 GILE ELECTRIC GENERAllNG PLANT M.PtY 1Q. SE FOR STA110t{JLQiOLQ Recommendation; l

, I 1he licensee needs to list the normally open ac motor operated globe l valves in the excess letdown and seal water leakoff line (X 49) in an l aapropriate procedure and identify the actions necessary to ensure that  ;

taese valves can be fully closed during an 5110 event. The valve i closure needs to be confirmed by position indication (local, ,

mechanical, remote, process information, etc.). ?'ils information i should be included with the other documentation that is to be i maintained by the licensee in support of the 500 submittals.

Remonse:

The excess letdown and seal water line containment isolation valves are nominal 2 inch diameter valves. In accordance with the criteria i presented in Regulatory Guide 1.155, paragraph 3.2.7, valves less than 3 inch nominal diameter are excluded from further consideration of l containment isolation capabilities. Therefore, containment integrity is maintained under SB0 conditions.

2.3 PROCEDURES AND 1rAIM M Staff Evalyalion of Unnsee Responsn the liccnsee stated that the procedural requirements for co)ing with an ,

S00 have been reviewed sad the grid restoration procedures iave been u3 dated to meet the requirements of the SB0 Rule. The licensee added tlTe following documents to the SB0 procedures: '

Black Start Procedures for Plant Vogtle; Restoration of Offsite AC Power for the Shutdown of VEGP.

The licensee also stated that the plant procedures have been reviewed, ,

and changes, if necessary to meet NUMARC 87-00, will be implemented in  !

the following areas:

Loss of all AC; Severe Weather; and System Operating Procedures for Diesel Generator Operation.  !

S-I i

e,e.r-+-*,.s,---:e - -

s l ATTACliMENT (CON 11NUED)

V0GTLE ELECTRIC GENERATING ptANT reply TO SE FOR JJATION BLACKQ21 4

The licensee indicated that these procedure changes will be completed  !'

within one year af ter the issuance of the SE.

The staff did not review the affected procedures or training. The staff expects the Ticensee to maintain and implement these procedures ,

including any others that may be required to ensure an appropriate '

response to an 500 event. Although persnnnel training requirements for an SB0 response were not specifically addressed in the licensee's submittals, the staff expects the licensee to implement the appropriate training to ensure an effective response to an SBO.

Recormendation:

Not Applicable.

Respon s The applicable plant procedures will be revised by february 1993 and [

appropriate training completed by June 1993 to meet NUMARC 87-00 and 10 CFR 50.63 requiren.cnts for satisfactorily coping with a station ,

blackout event.

2.4 PROPOSED _]iQDlf! CATIONS t

Staff Evaluation of LicefSee Resngnin The licensee stated that the following modifications would be required to attain the proposed 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> SB0 coping duration:

1. Lighting in the common main control room will be augmented to

, assure sufficient lighting after the 90 minutes of initial lighting j provided by self-containoa gel-cell tattery packs.

1

2. Six circuP hreakers in Unit 1 and seven circuit breakers in Unit 2 will be reblaced with larger size circuit breakers to avoid the potential of spurious tripping due to a temperature induced shift 1 in tripping characteristics at elevated ambient temperatures.

The licensee indicated that the above modifications will be completed within one year after the issuance nf the SE.

Secommendation:

L The licensee should include a full description including the nature and I objectives of the required modifications in the documentation that is l to be maintained by the licensee in support of the SB0 submittals.

l l

A11ACHMENT(CONTINUED) .

l V001tE LLECTRIC GEN [ RATING PLAN 1 RELL10.JiLLQ1L11al10Ll!1ACraul 1 Bucanin Both proposed modifications needed for coping with SB0 are being processed and implemented per plant procedures and will become a Quality Assurance (QA) record retained for the life of the plant.

1. The additional emergency lighting will be installed in the control room by February 1993.

2. The circuit breaker replacements required to avoid spurious trips due to a temperature induced shift in tripping chtracteristics l during SBO, for both Unit I and Unit 2, are complete. l 2.5 01A.LjiY ASSURA4 CLAW _ILCIE(ICALSPECILLCA110fis llaff Evaluation of iktDHt_J!tip.cniu The licensee did not address quality assurance (QA) or 15 pertaining to i the SB0 equipment.

I The TS for the 500 equipment are currently being considered generically by the NRC in the ntext of the TS Improvement Program and remains an open item at this time, llowever, the staff would expect that the plant procedures will reflect the appropriate testing and surveillance requirements to ensure the operability of the necessary SB0 equipment. i If the staff later determit.es that a TS regarding the 500 equipment is warranted, the licensee will be notified of the implementation requirements.

RcU Andal.igni  ;

The licensee should verify that the 580 equipment is covered by an appropriate QA program consistent with the guidance o' RG 1.155, -

A>pendix A. Furthur, this verification should be documented as part nf  :

tle package supporting the 500 Rule response.

Response

Station blackout coping equipment was procured as safety related; therefore, it is covered by an appropriate QA program.

Nonsafety related equipment ultitzed by operators during an 500 is emergency lighting and surveillance procedures are in place and performed to verify its continued operability. Therefore, the QA requirements of Regulatory Guide 1.155 are met with 500 coping equipment.

7-I t

4 ATTACHMElli (C0rJTINVED)

V0 GILE ELECTRIC GENERATING PLAN 1 REPLY 10 SE FOR STA110N BLA%QQ1 2.6 [QG REllABILITY PROGRAM

$1aff Evaluation of Licensee Eningnin The licensee's submittals on 5B0 did not specifically 4ddress the commitment to implement an EDG *eliability pregram to conform to the guidance of RG 1.155, Position 1.2. However, in the submittal of March 28, 1990, the licensee coramittt>d to maintain the EDG target reliability of 0.95. Although the licensee has committed to a reliability program pending resolution of Gl B 56, " Diesel Generator Reliability," they should implement a program that meets as a minimum the guidance of RG 1.155, Pesition 1.2.

Becommendalini lhe licensee should provide confirmation and include in the documentation supporting the 500 submittalt that is to be maintained by the licensee that such a program meeting the guidance of Regulatory Guide 1.155, Position 1.2, is in place or will be implementad.

EUMDin A procedure for the diesel generator reliability program is being developed to implement the guidelines of NUMARC 87-00 Appendix 0, which incorporates the requirements of Regulatory Guide 1.155. This procedure will be completed by June 1992.

1

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __N