ELV-02867, Forwards Responses to NRC Re Station Blackout.Sys Required to Function During Station Blackout Include, Auxiliary Feedwater Sys,Main Steam sys,RCS,post-accident Monitoring Sys & Class 1E Dc Sys
| ML20081G163 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/07/1991 |
| From: | Mccoy C GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20081G167 | List: |
| References | |
| 1000, ELV-02867, ELV-2867, NUDOCS 9106120276 | |
| Download: ML20081G163 (30) | |
Text
.
o ', o.. .y w cm r,
' i a:) h,ei e , Ce c94 m n.o
(< f O' 7 (i.m ' f P.
l5 f" iif <. p t f 1,i' s p g ,2 i, 9 i t , , ; e. c $.77 's L
c.K. nccoy
, , . - u. , c Georgia Power June 7, 1991 ELV-02867 1000 ,
1 Docket Nos. 50-424 50-425 I V. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:
V0GTLE ELECTRIC GENERATING PLANT RESPONSE TO STATION BLACK 0UT OVEST10NS Enclosed are responses to the seven questions concerning station blackout (SB0) that were transmitted to Georgia Power Company (GPC) by the NRC's letter dated May 10, 1991. During a conference call with the NRC on May 23, 1991, the staff expressed a desire for additional information concerning the quality assurance requirements for SB0 systems. The systems that are required to function during an SB0 have been identified as the following systemr: auxiliary feedwater system, main steam system, reactor coolant system, post accident monitoring system, class lE DC system and 120 VAC vital power system. Components of these systems are encompassed in the overall quality assurance program to provide control over activities affecting the quality of structures, systems, and components, as described in the Vogtle Electric Generating Plant FSAR section 17.2.
Sincerely, C. K. McCoy
! CKM/HWM/gmb l
Enclosures:
- 1. Response to Station Blackout Questiens
- 2. Calculation NX3AD01-01 xc: Georaia Power Comn.nv Mr. W. B. Shipman Mr. P. D. Rushton l
Mr. M. Sheibani NORMS
- U. S. Nuclear Reaulatory Commission
! Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Bonser, Senior Resident inspector, Vogtle 1 /
i 910612O276 910607 FDR ADOCK 05000424
/
[l h ' ;j
( P PDR [p' }
/ 9' ENCLOSURE 1 V0GTLE ELECTRIC GENERATING PLANT RESPONSE TO STATION BLACK 0UT QUESTIONS
- 1. Proposed Station Blackout Duration o How long will it take to manually transfer the 4.16 kV Class IE supply breaker to the alternate offsite power source, as described in Section 8.3 of the plant FSAR? Does this conform to the guidelines of NUMARC 87-00 Supplemental Questions / Answers?
Response
The proceduralized transfer of the 4160 V Class IE breaker to the alternate offsite power source involves racking out the breaker in the 4160 V Class IE switchgear and racking it into an empty cubicle in the same switchgear. ,
This transfer will take approximately 15 minutes, including travel time from the control room to the switchgear. This complies with the NUMARC 87-00 supplemental guidelines, section 3.2, in which the NRC allows for power transfer "... in a reasonable time, such as less than one hour."
El-1 1
/ i ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT RESPONSE TO STATION BLACK 0UT QUESTIONS
- 2. Condensate Inventory o Provide the contributing elements in your calculation of condensate inventory (i.e., decay heat, cooldown, steam generator level, shrinkage, etc.), including the basis for the assumed RCS leakage. If primary system cooldown is required, provide the final conditions. What is the total liquid volume on the secondary side of each steam generator?
Response
In conformance with NUMARC 87-00 guidelines, the amount of condensate necessary to cope with the Vogtle 4-hour SB0 duration was determined based on decay heat removal and depressurizing the steam generators (SGs) to approximately 265 psig. Implementation of Vogtle Emergency Operating Procedure 19100-C, " Response to Loss of All AC Power," will depressurize the steam generators to 265 psig and fill the steam generators to above the 5 percent narrow range level (10 percent after level tap modification).
This will result in a final RCS tenper&ture of approximately 4130F.
The basis for the assumed reactor coolant system (RCS) leakage is the 25 gpu per reactor coolant pump (RCP) allowed by NUMARC 87-00, which has been confirmed by Westinghouse as conservative. (See response to question 7.)
The required volume of condensate (203,000 gallons) was determined utilizing Westinghouse curve SSE-1515, which was originally provided for use in Vogtle
. Calculation X4Cl302V06, Rev 0, Condensate Storage Tank Verification.
l Technical Specifications require a condensate storage tank water volume of I
340,000 gallons.
The following is a list of the assumptions used to determine the condensate volume requirement:
l a. A 2-second delay is assumed before the reactor trips.
- b. The reactor trip occurs from 102 percent of rated thermal power.
- c. The main feedwater pt.mps and the reactor coolant pumps are shut of f immediately and coast to a stop,
- d. Steam generator blowdown is automatically terminated.
- e. The auxiliary feedwater flow is controlled to cool the reactor coolant to the no load programmed temperature of 5570F and maintain it there for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the reactor trip. The condensato storage tank (CST) volume required for this 2-hour period is 81,525 gallons.
El-2 l
l
/ s' ENCLOSURE I (CONTINUED)
V0G1LE ELECTRIC GENERATING PLANT RESPONSE TO STATION BLACK 0UT QUESTIONS
- f. After the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, the primary side is then cooled to 3500F in 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. The CST volume required for this 5-hour period is 121,823 gallons,
- g. When the reactor trips, the steam generators are assumed to be at low-low level with a water mass of 82,000 lbm per steam generator. At the end of the cooldown, all steam generators are at no load programmed levol with a steam volume of 2404 ft3 per steam generator. The total seccadary side steam generator volume is 5904 ft3 per steam generator,
- h. Decay heat continues to be released during this cooldown period. The decay heat model is based on Westinghouse BOP-FR-8, " Functional Requirements and Design Criteria, Residual Decay Heat Standard," Rev 1, March 1973. This decay heat model is very similar to the Branch Technical Position ASB 9-2 decay heat mode.
These assumptions are conservative for a 4-hour station blackout response, since the total time during which decay heat was assumed to be removed is 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />.
El-3
__ _ .- _ ~ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
/ .'
ENCLOSURE 1 (CONilNVED)
V0G1LE ELECTRIC GENERATING PLANT RESPONSE 10 STATION BLACK 0UT QUES 110NS
- 3. Battery Calculations o Provide battery load profiles and sizing calculations. Identify the major loads that will be stripped and the time that they are stripped, o Will the control room lighting be adequate for the required coping duration? Explain the status of the proposed design change with respect to control room lighting described in Jour April 12, 1989 submittal.
Response
A formal battery load capability calculation for the Vogtle SB0 scenario determined that the size of the station batteries is adequate to contend with a 4-hour coping duration without the need to resort to load stripping, i A copy of the Unit 1 battery calculation, NX3A001-01, is enclosed for your i use. The methodology and assumptions used in the battery calculation are in i compliance with NUMARC 87-00 guidalines, including the NUMARC 87-00 supplemental guidelines. Althot.g.. no load stripping is required or necessary, Vogtle Emergency Operating Procedure 19100-C,
- Response to Loss of All AC Power," makes provisions for load stripping. This phase would take place 1/2 to I hour after Procedure 19100-0 is initiated. !
The control room lighting has beca evaluated and found to deliver the required 10 footcandles for the first 90 minutes of the SB0 coping duration.
During this initial time frame, lighting is provided by self .ontained, gel-cell, battery-backed fluorescent fixtures. A permanent modification to augment the lighting for the required duration is expected to be complete by the end of 1992. Georgia Power Company's commitment to the NRC is to complete the modification within 1 year following NRC acceptance of the SB0 response. During the interim period, additional lighting is available from hand-held lights. Approximately 80, 8-hour battery packs are maintained '
charged by maintenance.
I El-4
t s' ENCLOSURE 1 (CONTINUED)
V0GTLE ELEC1RIC GENERATING PLANT RESPONSE TO STATION BLACK 0UT QUESTIONS ;
- 4. Compressed Air o Explain how steam release to the atmosphere will be accomplished under
$20 conditions. If local manual operation of the PORVs is required, has the issue of habitability in these areas been addressed?
Response
Steam release to the atmosphere will be accomplished under 50) conditions by the local, manual hydraulic operation of the steam generator atmospheric relief valves (ARVs). This local, manual operation of each ARV can be accomplished from a ground-level hand-pump station located in the main steam isolation valve (MSIV) area, approximately 8 feet below the main steam piping and atmospheric relief valves. Vogtle site procedures and training cover the local, manual hydraulic operation of the steam generator atmospheric relief valves.
The MSly area is a large room with openings to the outside on the side and roof. Therefore, the area will benefit from natural circulation during '
periods of loss of power. The SB0 temperature of 1260f for the MSIV area was based on a conservative analysis. No consideration for natural circulation or other cooling effects was assumed; therefore, the !?60f is considered to be a conservative temperature for the hydraulic hand-pum) area. (See response to question 5 for a discussion of the bases for tais assessment.) Therefore, the location of the ARV pump station is expected to remain habitable. Personnel entry into this crea during normal plant operation al:,o indicates that the area will be habitable under 500 conditions. Each pair of pump stations (i.e., one per ARV) is readily accessible from the entrance to the MSIV area, and as the adjustments of the ARVs are intermittent operations, the operator can remain at the entrance to the HSly areas and enter only when valve position adjustments are necessary.
Sound powered communication with the control room is available froin these areas.
The source of makeup water to the steam generators during the SB0 coping duration is the auxiliary feedwater system, and this flow is maintained by operation of the turbine driven auxiliary feedwater pump. The turbine driven auxiliary feedwater pump trip and throttle valve and the turbine speed governing valve are powered by the station class IE batteries and will remain functional during t1e SB0 coping duration. Auxiliary feedwater pump discharge to the steam generators is available via the auxilinry feed pump discharge valves HV-5120 to SG 4, HV-5122 to SG 1, HV-5125 to SG 2, and HV-5127 to SG 3. Power supply to these valves is from 125-VDC busos and is available during SB0. Only tnose valves corresponding to the sten generators selected for decay heat removal need to be operated. These vilves can be modulated as needed, from the control ronm, to maintain the desired SG 1evel.
El-5 t
_. . _ _ ., , _ . . , _ , . _ . . . . _ , _ _ , , - , _.,,._r , . - . ~ , , , , , _ , . . , ~ _ . . _ . _ _
/ ,
1 ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT RESPONSE 10 STATION BLACKOUT QUESTIONS
- 5. Loss of HVAC l
o Explain the method used to identify dominant areas of concern (DAts),
including a list of those areas that were considered.
o Describe the method that was used to perform heatup calculations (i.e., I were NUMARC methods used in all cases?). Provide the final calculated i temperatures, the initial temperatures assumed as well as any other quantifying assumptions, o Provide justification (s) that the trip setpoint derating of circuit breakers in the Class IE 125VDC/120VAC equipment rooms will not cause equipment operability problems. State the reason (s) for the change in the reported final temperature between the April 1989 (1270f) and the March 1990 (1200f) submittals for this area.
Response
l All components required to function during the SB0 event to achieve and I maintain safe shutdown were identified. Based on the NUMARC 87-00 criteria and supplemental guidelines, the areas which contained SB0 components were then reviewed to determine if any were dominant areas of concern (DAC).
Only the turbine driven auxiliary feedwater pump room (by definition) was a ,
DAC. However to assess the " reasonable assurance of operability' of all of r the SB0 components, all areas (outside containment) housing SB0 components were evaluated to determine their steady-state temperature during the SB0 coping duration.
The evaluation of the room SB0 ambient temperatures has been performed in accordance with the guidelines established in NUMARC 87-00, appendix f, '
including the NUMARC G7-00 supplemental guidelines. A tabulation of these areas, including their normal ambient room temperatures (note (a) below) and the maximum average SB0 ambient room temperaturer, is provided in tables 5.1 and 5.2. The calculated temperatures are within the acceptance limits for i the equipment in the rooms as given in NUMARC 87-00.
As a result of the supplemental guidelines, the original Vogtle SB0 loss of ventilation calculations were revised, where necessary, to use a higher initial room temperature to account for average wall temperature (note (b) below) . When several rooms showed unacceptable increases in the SB0 maximum average ambient temperatures due to the incorporation of the " average" ambient temperature, a reassessment was performed. To decrease these higher temperatures, the NUMARC 87-00 methodology of allowing for open doors to enhance cooling was employed. This resulted in the reduced final temperature in the lE 125-VDC/120-VAC equipment rooms between the April 1989 and March 1990 subinittals. Other calculation assumptions are listed in table 5.3.
El-6
i ;
i ENCLOSURE 1 (CON 11NUED)
V0G1LE ELECTRIC GENERAllNG PLAH1 RESPONSE 10 STATION BLACK 0UT QUES 110HS All SB0 maximum average ambient temperatures were calculated using the HUMARC 87-00 methodologies (including the supplemental guidelines) with the exception of the HSly areas, whose SB0 tem)erature was based on Vogtle Design Criteria DC-1007, " Environment." lie determination of the 0C-1007 abnormal temperature for the MSly areas was based on the loss of all normal ventilation in the HSly areas for a duration of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with all normal heat sources operating. Since these conditions envelop the 500 conditions, it was concluded that the MSIV area SB0 temperature would not exceed the DC-1007 abnormal temperature of 1260f.
All 120-VAC and 125-VDC circuit breakers were evaluated at a derated condition based on the SB0 maximum average ambient temperature, it was concluded that six circuit breakers in Unit 1 and seven circuit breakers in Unit 2 warrtnted replacement to ensure that the breakers would not inadvertently trip due to the elevated SB0 room temperatures, lhe Unit 2 breakers have been replaced; the Unit 1 breakers are scheduled for replacement in the f all of 1991.
Notes:
(a) The normal ambient room temperature is defined as "that temperature for which the equipment is expected to perform its safety-related function, as riiquired. on a continuous basis without impairment of its safety-related functional capability"; i.e., the maximum design ambient temperature. This is the temperature indicated in column 3 of tables 5.1 and 5.2.
(b) In accordance with NUMARC 87-00 supplemental guidelines, section 2,0, the NRC response to question 2.5 requires that the initial room temperature used in the analysis should be considered as equal to the average wall temperature, "If the room on the outside of the wall is warmer than the room on the inside, the average wall temperature should be used." This was utilized in the Vogtle SB0 loss of ventilation calculations.
El-7
\
i l ENCLOSURE 1 (CONTINVED)
TABLE 5.1 V0GTLE UNIT 1 AREAS CONTAINING COMP 0NENTS REQUIRED TO OPERATE DURING AN SB0 Areas Components Required Normal 500 Maximum for SB0 Ambient Average Ambient Temperature Temperature (OT) (OT)
(Note 4)
MSIV Areas Mn Stm isol Valves 115 126 (HV3006A/B, HV3016A/B, HV3026A/B k HV3036A/B) 1 Atm Relief Valves (HV3000, HV3010, HV3020
& HV3030)
Turbine Driven Turbine driven aux feed 104 121 AfW Pump Rm water pump and controls Main Control Instrumentation and 85 85 Room (Rm 163) controls Aux Bldg SG-1 Steam Line 103 115 Room A09 Pressure Transmitters (PT-0514 S -0515)
Aux Bldg AfW to SG-1 120 120 l Room A10 flow Transmitter (FT-5152)
Aux Bldg AfW to SG-4 100 115 Room A17 flow Transmitter (FT-5150) !
Aux Bldg SG-4 Steam Line 114 133 Room 107 Pressure Transmitters (note 2)
(PT-0544 & -0545)
Aux Bldg Inverter (18D1112) 85 10/
Room 116 Vital AC Pnl (IBY28)
Aux Bldg Inverter (lADilll) 85 104 Room 118 Vital AC Pnl (IAY2A)
Control Bldg SG-3 Steam Line 100 105 Room A51 Pressure Transmitters (PT-0534 & -0535)
Control Bldg AFW to SG-3 100 107 Room A55 flow Transmitter (fT-5153)
El-8
[NCLOSURE 1 (COHilNVID)
TABLE 5.1 (Cont'd)
V0 Gile VH11 1 AREAS CONTAINiliG COMPON[HIS REQUIRED 10 OPERATE DURING AN 500 Areas Components Required Normal 500 Maximum for SB0 Ambient Average Ambient lemperature Temperature (Of) (of)
Ufoj e 4)
Control Bldg AfW to SG-2 100 107 Room A62 Flow Transmitter (f1-5151)
SG-2 Steam Line Pressure Transmitters (Pl-0524 & -0525)
Control Bldg Neutron flux 75 92 Room 230 Monitoring DPU (D5-0068)
Control Bldg Neutron flux 100 103 Room A48 Monitoring DPU (05-006A)
Control Bldg Neutron flux Monitoring 100 (Note 1)
Room B78 Pre-amp (P5-NFA)
Control Bldg Neutron flux Monitoring 100 (Note 1)
Room B65 Pre-amp (PS-NfB)
Control Bldg DC MCC (IBDlM) 85 119 Room B47 DC SWGR (IBD1) (Note 3)
Inverter (18D112)
Vital AC Pnl (IB41B)
DC Pnl (18011)
DC Pnl (18012)
Control Bldg DC SWGR (1001) 100 119 Room B48 Inverter (1D0114) (Note 3)
Vital AC Pnl (IDYlB)
DC Pnl (10D11)
Control Bldg DC HCC (IADlM) 85 119 Room B52 DC SWGR (LAD 1) (Note 3)
Inverter (IADill)
Vital AC Pn1 (lAYl A)
DC Pnl (IADll)
DC Pn1 (LAD 12)
El-9 l
o :
ENCLOSURE 1 (CONilNUED)
TAD! E 5.1 (cont'd)
V0GTit UNil 1 ,
AREAS CONTAINING COMPONENTS RLQUIRED 10 l OPCPA1E DURING AN SB0 Areas Components Required Normal 500 Haximum
- for SB0 Ambient Average Ambie,. !
Temperature Temperature (OT) (UF) l L!ioic_.O ___. _
Control Bldg DC SWGR (1001) 100 119 ,
Room B55 Inverter (10D113) (Note 3)
Vital AC Pn1 (ICYlA)
DC Pn1 (10011) ;
Control Bldg DC HCC (ICDlH) 85 100 Room B84 Control Bldg Station Battery (10010) 75 (Note 1)
Room B44 Control Bldg Station Battery (IBDlB) 75 (Note 1) ;
Room 049 Control Bldg Station Battery (IADlR) 75 (Note 1)
Room B54 i Control Bldg Station Battery (20010) 75 (Note 1)
Room B56 Conds Storage Conds Sto Tank Level Amb Amb Tank 1 1ransmitters (LT-5101 & -5111)
Conds Storage Conds Sto Tank Level Amb Amb i Tank 2 Transmitters (LT-5104 & -5116)
Note 1: Due to the absence of any significant heat loads in Control ,
Building rooms B44, B49, 854, B56 (station class lE battery !
rooms), B65, and B78, it was not necessary to calculate the resulting ambient temperatures under 580 conditions.
Note 2: Based on the Unit 1 operating plant temperature survey.
Note 3: Requires the following doors to be open during an SB0:
Rm. B47 - door 854 Rm. B48 - doors B57 and B56 Rm. BS2 - door 859 I
Rm. 855 - door B61 Note 4: This column represents Design Manual 00-1007 normal temperatures.
Initial room temperatures used in calculating the "SB0 Maximum Average Ambient Temperature" reficct the NUMARC " average" ambient temperatures and therefore may be higher.
El-10 i
o ;
ENCLOSURE 1 (CONilNVED) 1 1ABLE 5,2 V0G1LE UNil 2 AREAS CONTAINING COMPONENTS REQUIRED TO OPERATE OURING AN SCO Areas Components Required Normal SB0 Haximum for 500 Ambient Average Ambient I Temperature Temperature (OT) (Of)
Ulote 4)
MSly Areas Mn Stm 1501 Valves 115 126 (HV3006A/B,llV3016A/B, ilV3026A/B & ilV3036A/B)
Atm Relief Valves (llV3000, llV3010, llV3020
&ilV3030)
Turbine Driven Turbine driven aux feed 104 121 AIW Pump Rm water pump and controls l
Main Control Instrumentation and 85 85 Room (163) controls Aux Bldg SG-1 Steam Line 103 115 Room A103 Pressure Transmitters ,
(PT-0514 & -0515) l Aux Bldg AfW to SG-1 120 120 Room A102 flow Transmitter (f1-5152) i Aux Bldg AfW to SG-4 100 115 flow Transmitter Room A61 (fi-5150)
Aux Bldg SG-4 Steam Line 114 133 Room 155 Pressure Transmitters (Note 2)
(PT-0544 & -0545)
Aux Bldg Inverter (2001112) 85 107 Room 147 Vital AC Pnl (2BY28) l l
Aux Bldg Inverter (2AD1111) 85 104 Room 149 Vital AC Pnl (2AY2A)
Control Bldg SG-3 Steam Line 100 105 Room A14 Pressure Transmitters (PT-0534) l j El-ll
o .
I liitt05URE 1 (C0tilitiVED) i 1ABLE 5.2 (Cont'd)
V0G1LE Vill 12 AR[AS C0t4TAllill4G COMP 0li[fil5 REQUIR[D 10 OPLRATE DURil4G Ali 5B0 Areas Components Required flormal SB0 Maximum for SB0 Ambient Average Ambient Temperature Temperature (Of) (01)
(N01C_i)
Control Bldg AfW to LG-2 100 108 Room A02 flow Transmitter (IT-5151)
SG-2 Steam Line Pressure Transmitter (PT-0525)
Control Bldg lieutron flux 75 91 Room 264 Monitoring DPU 05-006B Control Bldg ficutron flux 100 103 Room A16 Monitoring DPU 05-006A Control Bldg lieutron flux Monitoring 100 (fiote 1)
Room B02 Pre-amp (P5-lifA)
Control Bldg lieutron flux Monitoring 100 (liote 1)
Room B19 Pre-amp (P5-lifB)
Control Bldg DC MCC (2BDlM) 85 119 Room B3G DC SWGR (2BDl) (flote 3)
Inverter (200112)
Vital AC Pnl (2BalB)
DC Pnl (2B011)
DC Pnl (2B012)
Control Bldg DC SWGR (2001) 100 119 Room B31 Inverter (20D114) (tiote 3)
Vital AC Pnl (20YlB)
DC Pnl (2B011)
Control Bldg DC MCC (2ADlM) 85 119 Room B29 DC SWGR (2ADl) (tiote 3)
Inverter (2ADlll)
Vital AC Pn1 (2AYlA)
DC Pn1 (2ADll)
DC Pnl (2AD12)
El-12 l
o ;
[NCLOSURE I (CONTINV[D)
TABLE 5.2 (Cont'd)
V0GTLE UNIT 2 AREAS CONTAINING COMPONENTS REQUIRED 10 OPERATE DURING AN SB0 Areas Components Required Normal SB0 Maximum for SB0 Ambient Average Ambient Temperature Temperature (Of) (Of)
._ _ (Hole 3)
Control Bldg AfW to SG-3 100 107 flow Transmitter Room A10 (fT-5153)
SG-3 Steam Line Pressure Transmitters (PT-0535)
Control Bldg SG-2 Steam Line 100 105 Room A04 Pressure Transmitter
- (PT-0524)
Control Bldg DC SWGR (2001) 100 119 Room B26 Inverter (20D113) (Note 3)
Vital AC Pnl (20YlA)
DC Pn* (20011)
Control Bldg DC HCC (2CDlH) 85 100 l
i Room 885 Control Bldg Station Battery (20D1B) 75 (Note 1)
Room B37 Control Bldg Station Battery (2B01B) 75 (Note 1)
Room 832 Control Bldg Station Battery (2ADlB) 75 (Note 1)
Room B27 Control Bldg Station Battery (20018) 75 (Note 1) l Room B25 Conds Storage Conds Sto Tank Level Amb Amb Tank 1 Transmitters (LT-5101 & -Sill)
Conds Storage Conds Sto Tank level Amb Amb Tank 2 Transmitters (LT-5104 & -5116)
El-13 i
CNCLOSURE 1 (CON 11NVED)
TABLE 5.2 (cont'd)
V0GTLE UNil 2 AREAS CONTAINING COMPONLNTS REQUIRED 10 OPERATE DURING AN SB0 Note 1: Control building rooms B25, B27, B32, B37 (station class 10 battery rooms), 802, and B19 have been evaluated for loss of 1 ventilation effects. Due to the absence of any significant heat loads in these rooms (residual or existing), it was not necessary to calculate the resulting ambient temperatures under 5D0 conditions.
- Note 2: Based on the Unit 1 operating plant temperature survey.
Note 3: Requires the following doors to be open during an 500:
Rm. B26 - door B28 Rm, B29 - door 834 Rm. 831 - doors B36 and B37 Rm. 836 - door 839 i Note 4: This column represents Design Manual DC-1007 normal temperatures. '
initial room temperatures used in calculating the "500 Maximum !
Average Ambient Temperature" reflect the NUMARC " average" ambient I temperatures and therefore may be higher.
l t
I l
El-14
ENCLOSURE 1 (CON 11NVED) l TABLE 5.3 CALCULATION ASSUMPTIONS / BASES VIILIZED IN lilE V0 GILE UNIT 1 AND UNIT 2 SB0 AMBl[H1 1[MPERA1VRE ANALYSIS
- 1. All rooms housing equipment required for the 5B0 were reviewed for ap)1icability. 1 hose rooms containing only the station batteries and/or otier non-heat producing equipment were then excluded from the final list.
- 2. The Vogtle Unit I and Unit 2 main control rooms are open to each other.
These two rooms share a common ductwork system served by four 100-percent .
capacity, independent, safety-related HVAC systems. Any one of these four 1 systems is capable of providing the necessary cooling to maintain the normal
..mbient
- conditions for both control rooms. Therefore, during the 500 coping duration, the affected unit will receive cooling from the unaffected unit.
emergency diesel generator powered, control room HVAC system.
- 3. In accordance with the NUMARC 87-00 guidelines, transmission loads were i culuded and residual loads were considered on a case-by-case basis. All AC lighting was excluded from the room heat loads.
- 4. In accordance with the NUMARC 87-00 supplemental guidelines the ambient room temperature (s) at the inception of the 500 must be the average of the subject room and the adjacent room ambient temperatures, for the Vogtle calculations, this basis was employed only if the adjacent ambient temperature was higher than the subject SB0 room. Ior those cases when the adjacent room ambient temperature was lower than the subject room ambient temperature, no average was taken.
- 5. The condensate storage tanks are designed for and subject to ambient conditions and are therefore unaffected by the 580 conditions within the plant.
- 6. The 500 conditions (main steam and feedwater isolation. steam dump through the ARVs, loss of ventilation, loss of AC power, piping residual loads, etc.) for the MSIV areas in the auxiliary and control buildings are enveloped by the conditions used in determining the DC-1007 abnormal temperature of 1260f. Therefore, the MSIV average area ambient temperature will be no higher than 1260f.
El-15
e ;
ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT RESPuriSE 10 STATION BLACKOUT QUESTIONS l
- 6. Containment Integrity o The assurance of providing adequate containment integrity requires that all CIVs that are normally open or closed, fail as is, and cannot be excluded by the five criteria given in R.G. 1.155 to be included in a procedure. Identify the penetrations or CIVs that come under this !
category.
Rosponse:
All containment isolation valves were assessed in accordance with Regulatory '
Guide 1.155 and NUMARC 87-00 criteria. Those valves which fell under one or more of the five exclusion criteria were eliminated from further review.
Each remaining valve was then individually evaluated to determine if its closure and/or indication of closure was required. This evaluation is provided below, ,
As required by Regulatory Guide 1.155 and NUMARC 87-00, appropriate containment integrity must be provided during the recuired duration of the S80. Required containment integrity must be providec ir. dependent of the '
preferred offsite and onsite emergency AC power supplies for valve position indication and for closure of containment isolation valves.
A review of the Vogtle containment / penetration / isolation valve information (Vogtle FSAR table 6.2.4-1) revealed that most containment isolation valves fell into one (or more) of the Regulatory Guide 1.155/NUMARC 87-00 five allowable exemptions. The remaining valves are identified and discussed below. (Valve numbering for both units is identical, and therefore no unit I identification is given in the discussion.)
- a. Main steam valves HV-3009 and HV-3019: These two valves allow steam flow from the steam generators to the auxiliary feedwater pump turbine l and are required to be open to mitigate SBO.
- b. Cold leg safety injection line valve HV-8835: This containment isolation valve is a normally open, AC powered, fail-as-is valve. ,
Isolation is provided by the exempt inboard containment isolation valves.
- c. Cold leg boron injection valves HV-8801A and HV-88010: These valves are normally closed, fail-as-is, and are AC powered. Upon loss of AC wiwer, the valves will remain closed. Redundant isolation is also provided by the exempt inboard containment isolation valves.
El-16
1 i
ENCLOSURE 1 (CONTINUED) 1 V0GTLE ELECTRIC GENERATING PLANT RESPONSE 10 STATION BLACKOUT QUESTIONS
- d. Hot leg safety injection valves HV-8802A and HV-88026: These valves are AC powered, normally closed, fail-as-is valves. Upon loss of AC power, the valves will remain in the closed position. Redundant isolation is .
also provided by the exempt inboard containment isolation valves. l
\
- e. Containment saray supply line valve HV-9001A (Train A) and valve HV-90010 '
(Train B): T1ese two valves are AC powered, normally closed, fail-as-is valves. Upon loss of AC power, these valves will remain in the closed position. Redundant isolation is also provided by the exempt inboard containment isolation valves,
- f. Residual heat removal (RHR) emergency sump suction line valve HV-8811A (Train A) and HV-88110 (Train B); containment spray emergency sump suction line valve HV-9002A (Train A) and HV-90020 (Train B): Each valve provides the only means of containment isolation for its respective i suction line. These valves are normally closed, AC powered, fail-as-is valves and will remain closed following a loss of AC power. Plant procedures require verification that these valves are closed prior to the plant startup,
- g. Normal charging line valve HV-8105: 1his valve is a normally c; en, AC sowered, fail-as-is containment isolation valve. Isolation is provided
)y the exempt inboard containment isolation valves.
h, Residual heat removal pump discharge to hot leg line valve HV-8840: This outboard containment isolation valve is a normally closed, AC powered, fail-as-is valve. Upon loss of AC power, the valve remains in the closed position. Redundant isolation is also provided by the exempt inboard containment isolation valves,
- i. Residual heat removal discharge into cold leg valve HV-8809A (Train A) <
and valve HV-88098 (Train B): 1hese outboard containment isolation ;
valves are normally open, AC powered, fail-as-is containment isolation valves. Containment isolation is provided for train A by inboard valve HV-8890A (normally closed, fail closed) and check valves 147 and 148.
Containment isolation ir provided for train B by inboard valve HV-80908 (normally closed, fail closed) and check valves 149 and 150.
J. Residual l eat removal suction from hot leg valve HV-8701A (Train A) and HV-8702A (Train B): These valves are normally closed, AC powered, fail-as-as containment isolation valves. However, these valves are interlo;ked with RCS pressure and can only be opened when the RCS is in the hot shutdown condition. Therefore, these valves will be closed prior to and will remain closed during an SB0 event since it is assumed to occur with the RCS at operating pressure.
El-17
ENCLOSURE 1 (CONTINUED)
V0G1LE ELECTRIC GENERATING PLAHi RESPONSE TO STATION BLACK 0UT QUESTIONS Containment isolation valve position indication is addressed in section C, paragraph 3.2.7 of Regulatory Guide 1.155. All Vogtle containment isolation valves listed in FSAR table 6.2.4-1 were reviewed for these requirements. Those containment isolation valves which fell under one or more of the five 5 exclusion criteria are excluded from the position indication requirement under an 500.
Position indication requirements for normally closed, fail-as-is valves is discussed further in table 6.1-1 (Unit 1) and table 6.2-1 (Unit 2).
Normally open, fail-as-is valves are listed in table 6.1-2 (Unit 1 ) and table 6.2-2 (Unit 2), and either position indication is provided or the rationale for not requiring position indicat ion is included.
Based on the five exclusion criteria and the evaluation provided, it was concluded that no operator action is required to assure containment isolation valve closure.
Although closure of those outboard containment isolation valves not excluded by one of the five criteria is not required, Vogtle Emergency Operating Procedures address the local, manual closure of outboard containment isolation valves.
El-18 1
l
- 1 ENCLOSURE 1 (CONTINUED)
TABLE 6.1-1 UN11 1 NORHALLY CLOSED FAIL-AS-IS CONTAINMENT ISOLA 110N VALVES Penet. Equipment Redundant Status / Position No. Tag No. Isolation failure Indication Valve Mode Required 31 1HV-8802B 1HV-8824 NC/fC No 1204-122 Check Valve 1204-123 Check Valve 32 1HV-8801A 1204-013 Check Valve No lHV-88018 IHV-8843 NC/FC Ho 33 IHV-8802A IHV-8881 NC/fC No 1204-120 Check Valve 1204-121 Check Valve 34 IHV-9001B 1206-016 Check Valve No 35 1HV-9001A 1206-015 Check Valve No 36 IHV-88110 None N/A See Note 1 37 IHV-8811A None N/A See Note 1 38 1HV-90028 None N/A See Note 2 39 IHV-9002A None N/A See Note 2 56 IHV-8840 Power Lockout is provided No 59 lHV-8701A Power lockout is provided No 60 lHV-8702A Power lockout is provided No 83 IHV-2626A Power lockout is provided No 83 IHV-2627A Power lockout is provided No 1
84 IHV-2628A Power lockout is provided No l
84 IHV-2629A Power lockout is provided No 100 1HV-2624A 1508-012 NC/LC No 100 1HV-2624B 1508-012 NC/LC No El-19 l
I 1
l ENCLOSURE I (CONTINUE 0)
TABLE 6.1-1 (Cont'd)
UNIT 1 NORMALLY CLOSED, Fall-AS IS CONTAINMENT ISOLATION VALVES Notes:
- 1. Since these RHR emergency sump suction valves are normally closed and they fail-as-is, they will not open on loss of power. These valves are also closed during all normal modes of plant operation and their closed status is verified by plant procedures' prior to plant startup. No position indicatica is required.
1
- 2. Valves IHV-9002A and lHV-9002B are in the suction line of the I containment spray pumps and are connected to the containment !
emergency sumps. Since these motor operated valves are normally closed during all normal modes of plant operation and stay closed I on loss of offsite power, position indication is not required. '
Their closure is verified >y plant procedures prior to plant startup.
El-20
EliCLOSURE I (C0f4Til1UED)
TABLE 6.1-2 UNIT 1 NORMALLY OPEN, Fall-AS-IS CONTAINMLili ISOLATION VALVES Equipment Line Description Operator Normal failure Note Tag No. Size Mode rioda fio .
lHV-3009 4" MS to AfW Elec. Mtr 0 FAI 1 Pump Driver lilV-3019 4" MS to AfW Elec. Mtr 0 FAI 1 Pump Driver MS to AFW Pump Driver liiV-1978 10" ACCW Supply Elec. Mtr 0 fAl 2 IHV-1979 10" ACCW Supply Elec. Mtr 0 FAI 2 liiV-1974 10" ACCW Return Elec. Mtr 0 FAl 2 IHV-1975 10" ACCW Return Elec. Mtr 0 FAI 2 IHV-2134 8" NSCW Supply to Elec. Mtr 0 FAI 2 reac cav.
coolers 1HV-2138 8" liSCW return Elec. Mtr 0 FAI 2 from reac.
cav coolers lHV-2135 8" NSCW supply to Elec. Mtr 0 FAI 2 reaC.Cav.
Coolers liiV-2139 8" NSCW return Elec, Mtr 0 FAI 2 from reac.
caV. coolers IHV-8835 4 Safety inj. to Elec. Mtr 0 FAI 3 cold leg lHV-8105 3" flormal charging Elec. Mtr 0 FAI 4 line liiV-8809A 8" RHR loop into Elec. Mtr 0 FAI 5 cold leg 1HV-8809B 8" RHR loop into Elec. Mtr 0 FAl 5 cold leg El-21
[NCLOSURL 1 (CON 11 HUED)
TABLE 6.1-2 (Cont'd)
UNIT 1 NORMALLY OP[N, Fall-AS-IS CONTAINMENT ISOLATION VALVES Equipment Line Description Operator Normal failbre Note Tag No. Size Mode Mode No.
lilV-1806 8" NSCW supply to Elec Mtr 0 FAI 2 cont. coolers lilV-1807 8" NSCW supply to Elec Mir 0 FAl 2 cont. coolers lHV-1808 8" HSCW supply to Elec. Mtr 0 FAI 2 cont. coolers lilV-1809 8" NSCW supply to Elec Mtr 0 FAI 2 cont. coolers lHV-1831 8" NSCW return Elec Mtr. O FAI 2 from cont.
coolers lilV-1823 8" NSCW return Elec Mtr. O FAl 2 from cont.
coolers lilV-1830 8" NSCW return Elec. Mtr 0 FAI 2 from cont, coolers lilV-1822 8" NSCW return Elec. Mtr 0 FAI 2 from cont.
coolers lloin:
- 1. These valves are required to operate to mitigate 580 and valve position indication is available during SBO. The valves are powered from Class IE, 125 VDC MCCs.
- 2. These valves are in non-radioactive closed-loop ACCW and NSCW systems that do not communicate with it containment atmosphere.
These closed loop systems are not expected to be breached in tha event of a station blackout. Per Sec. 3.2.7, sub item 4, of Regulatory Guide 1.155, valve position indication is not required.
- 3. Valve lilV-8835, Safety injection to Cold Leg, is normally open and is a fail-as-is containment outboard isolation valve. Containment isolation is provided by inboard valves lilV-8823 (normally closed, fail closed) and check valves 143, 144, 145, and 146. Therefore valve position indication is not required.
El-22
i ENCLOSURE 1 (CON 11NVED) 1ABLE 6.1-2 (Cont'd.) ;
l UNil 1 NORKALLY OPEN, Fall-AS-IS CONTAINMENT ISOLATION VALVES l
- 4. Valve IHV-8105, Normal Charging Line, is normally open and is a l fall-as-is containment outboard isolation valve. Containment 1 isolation is provided by inboard check valve 032. Therefore, ,
l valve position indication is not required. l
- 5. Residual heat removal discharge to cold leg valves lilV-8009A and lHV-88090 are normally open, fail-as-is containment outboard isolation valves. Containment isolation is provided for train A by inboard valve IllV-8890A (normally closed, fail closed) and check valves 147 and 148. Containment isolation is provided for train B by inboard valvo lHV-88908 (normally closed, fail closed) and check valves 149 and 150. Therefore, valve position indication is not required.
l l
l l
i I
l l
i 1
i El-23 l
i
ENCLOSVRE 1 (CONTINVED)
TABLE 6.2-1 UNIT 2 NORMALLY CLOSED, FAIL-AS-IS CONTAINMENT ISOLA 110N VALVES Penet. Equipment Redundant Status / Position No. Tag No. Isolation failure Indication Valve Mode Required 31 2HV-88028 2ilV-8824 NC/fC No 1204-122 Check Valve 1204-123 Check Valve 32 2HV-8801A 1204-013 Check Valve No 2HV-88018 2HV-8843 NC/fC No 33 2ilV-8802A 2HV-8881 NC/fC No 1204-120 Check Valve 1204-121 Check Valve 34 2HV-90018 1206-016 Check Valve No 35 2ilV-9001A 1206-015 Check Valve No 36 2HV-8811B None N/A See Note 1 37 2llV-8811A None N/A See Note 1 38 2HV-9002B None N/A See Note 2 39 2HV-9002A Hone N/A See Note 2 56 2HV-8840 Power Lockout is provided No 59 2HV-8701A Power lockout is provided No 60 2HV-8702A Power lockout is provided No 83 2HV-2626A Power lockout is provided No 83 2HV-2627A Power lockout is provided No 84 2llV-2628A Power lockout is provided No 84 2HV-2629A Power lockout is provided No 100 2HV-2624A 1508-012 NC/LC No 100 2HV-26248 1508-012 NC/LC No El-24 i
n m . .. . . , .- . m._,---,,-r,y,,-- .. m ,, .m . . . - . ., . . _ , , , . , - _ , _
ENCLOSURE 1 (CONilHUED)
TABLE 6.2-1 (cont'd)
UNIT 2 NORMALLY CLOSED, Fall-AS-IS CONTAINMENT ISOLATION VALVES Notes:
- 1. Since these RHR emergency sump suction valves are normally closed and they fail-as-is, they will not open on loss of power. These valves are also closed during all normal modes of plant operation and their closed status is verified by plant procedures prior to plant startup. No position indication is required.
- 2. Valves 2HV-9002A and 2HV-90020 are in the suction line of the containment spray pumps and are connected to the containment emergency sumps. Since these motor operated valves are normally closed during all normal modes of plant operation and stay closed on loss of offsite power, aosition indication is not required.
Their closure is verified ]y plant procedures prior to plant startup.
El-25
_ _ , . - _ . ~ . . _ _ . _ _ . . _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _
- 1 ENCLOSURE 1 (CONTINUED)
TABLE 6.2-2 UNIT 2 NORMALLY OpEN, Fall-AS-IS CONTAINMENT ISOLATION VALVES Equipment Line Description Operator Normal failure Note Tag No. Size Mode Mode No.
2HV-3009 4" HS to AfW Elec. Mtr 0 FAI 1 Pump Driver 2HV-3019 4" MS to AfW Elec. Mtr 0 FAI 1 Pump Driver MS to AfW Pump Driver 2HV-1978 10" ACCW Supply Elec. Mtr 0 FAI 2 2HV-1979 10" ACCW Supply Elec. Mtr 0 FAI 2 2HV-1974 10" ACCW Return Elec. Mtr 0 FAI 2 l
2HV-1975 10" ACCW Return Elec Mtr 0 FAI 2 2HV-2134 8" NSCW Supply to Elec. Mtr 0 FAI 2 reac cav.
coolers
cav coolers 2HV-2135 8" NSCW supply to Elec. Mtr 0 FAI 2 reac.cav.
coolers 2HV-2139 8" NSCW return Elec. Mtr 0 FAI 2 from reac.
, cav. coolers 2HV-8835 4" Safety inj. to Elec. Mtr 0 FAl 3 cold 109 2HV-8105 3" Normal charging Elec. Mtr 0 FA! 4 line 2HV-8809A 8" RHR loop into Elec. Mtr 0 FAI 5 cold leg 2HV-8809B 8" RHR loop into Elec Mtr 0 FAl 5 cold leg El-26
[NCLOSURF 1 (CONTINUED)
TABLE 6.2-2 (Cont'd) i j UNIT 2 NORMALLY OPEN, Fall-AS-IS CONTAINMENT ISOLATION VALVES i i
Equipment Line Description Operator Normal failure Note Tag No. Size Mode Mode No.
1 .
2HV-1806 8" NSCW supply to Elec. Mir 0 FAI 2 4 cont, coolers l 2HV-1807 8" NSCW supply to Elec. Mtr 0 FAI 2 cont. coolers 2HV-1808 8" NSCW supply to Elec. Mtr 0 F41 2 cont, coolers ,
2HV-1809 8" NSCW supply to Elec. Mtr 0 FAI 2 '
cont. coolers 2HV-1831 8" NSCW return Elqc. Mtr 0 FAI 2 from cont.
coolers 2HV-1823 8" NSCW return Elec. Mir 0 FAI 2 from cont.
Coolers 2HV-1830 8" NSCW return Elec. Mtr 0 FAI 2 l from cont.
c.oolers 2HV-1822 8" NSCW return Elec. Mtr 0 FAI 2 from cont, coolers
!!Q11ui:
- 1. These valves are required to operate to mitigate SB0 and valve position indication is available during SB0. The valves are '
powered from Class IE, 125 VDC HCCs.
- 2. These valve, are in non-radioactive closed-loop ACCW and NSCW systems that do not communicate with the containment atmosphere.
l These closed loop systems are not expected to be breached in the event of a station blackout. Per Sec. 3.2.7, sub item 4, of Regulatory Guide 1.155, valve position indication is not required.
l 3. Valve 2HV-8835, Safety injection to Cold Leg, is normally open and I is a fail-as-is containment outboard isolation valve. Containment l isolation is provided by inboard valves 2HV-882s (normally closed,
, fail closed) and check valves 143, 144, 145, and 146. Therefore I valve position indication is not required.
El-27
-,m. -,-,-v, ._,_,_,..-_____-% _-e,ey, . , - . , , _ .% r.__.. ,__..g._ , +r ,-,.,._-rr _,,,..y., ,-eyv--,_ gw.
ENCLOSURE I (CONTINVED) 1ABLE 6.2-2 (Cont'd)
UNIT 2 NORMALLY OPEN, Tall-AS-IS CONTAINMENT ISOLA 110N VAL'iES
- 4. Valve 2HV-8105, Normal Charging Line, is normally open and is a fail-as-is containment outboard isolation valve. Containment isolation is provided by inboard check valve 032. Therefore, valve position indication is not required.
- 5. Residual heat removal discharge to cold leg valves 2HV-8809A and 2HV-88090 are normally apen, fail-as-is containment outboard isolation valves. Containment isolation is provided for train A by inboard valve 2HV-8890A (normally closed, fail closed) and check valves 147 and 148. Containment isolat'on is provided for train B by inboard valve 2HV-8890B (normally closed, fail closed) and check valves 149 and 150. Therefore, valve position indication is not required.
El-28 F
- m. - . . , . __ _ _ , . - , - . _ _ - . _ . _ _ __ m _ _ - _ _ _ , _ . , _ _ , _ _ , - , _ , -
ENCLOSVRE 1 (CONilNUlD)
V0GTLi ELCCTRIC GENERATING PLANT RESPONSE 10 STATION BLACK 0UT QUES 110NS
- 7. RCS Inventory o Provide the initial conditions used for your calculation of RCS inventory (including assumed leakage, total RCS volume, the volume required to cover the core, initial and final reactor temperatures and pressures).
Response
The Vogtle 500 evaluation assumes the plant will be at full power at the onset of the 500.
The Westinghouse evaluations concerning RCP seal leakage and natural circulation were based on the results presented in section 8.2 of WCAP-10541, rev 2, Westinghouse Owners Group Report on Reactor Coolant Pump Seal Performance following a loss of All AC Power. Even though a )lant specific analysis was not performed for Vogtle, the results from tie WCAP were determined by Westinghouse to be applicable to Vogtle.
The initial conditions for the Westinghouse calculation are presented in section 8.2 of WCAP-10541 and are repeated below:
Pressurizer Volume - 1800 ft3 Pressurizer Water Volume - 1116 f t3 Dead Volume (upper head and plenum) - 1500 ft3 Accumulator Water Volume - 3400 f t3 U-Tube Bend Volume for 4 SGs - 150 f t3 Cold Side Volume for 4 Loops - 1200 ft3 RCS Volume (minus pressurizer and dead volumes) - 9150 ft3 Initial System Pressure - 2250 psia Initial Tem)erature -5650f Initial teac Rate - 21 gpm per reactor coolant pump final System Pressure (018.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />) 300 psia final Temperature (018.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />) - ai70f ll The fluid volume required to Westinghouseasbeing2550ftgoverthecorehasbeenestimatedby (core + downcomer fluid volume).
The total RCS leakage for the SB0 evaluation previously submitted was assumed to be eouivalent to 25 gpm per RCP or a total of 100 gpm. This total did not include the Vogtle Technical Specifications limits of 10 gpm identified and 1 gpm unidentified RCS leakage. Based on the Westinghouse calculated 21 gpm per RCP via seal leakage and the ability to maintain natural circulation and maintain the core covered for approximately 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />, conservatively assuitng the additional RCS leakage will reduce the 18-hour time, but e'll remain well within the Vogtle 4-hour coping duration.
El-29
, , . - -.. . _ - - _ . . - - - _ - - - - . - - . . - _ - _ .