ML20214V460
| ML20214V460 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 06/05/1987 |
| From: | GULF STATES UTILITIES CO. |
| To: | |
| Shared Package | |
| ML20214V064 | List: |
| References | |
| NUDOCS 8706120107 | |
| Download: ML20214V460 (15) | |
Text
_ _ - _ _ _ _ _ _ _ _ _ _ _
CONTAINMENT SYSTEMS ORYWELL AVERAGE AIR TEMPERATURE LIMITING CON 0! TION FOR OPERATION 3.6.2.6 Drywell average air temperature shall not exceed 444ap, 145 F.
APPLICA81LITY: OPERATIONAL CON 0!TIONS 1, 2, and 3.
ACTION:
145 F With the drywell average air temperature greater than 44086, reduce the average air temperature to within the limit within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least NOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.2.6 The drywell average air temperature shall be the arithmetical average of the temperatures at the following locations and shall be determined to be within the limit at least once per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:
ELEVATION AZIMUTH a.
- 145' 20* 1 A 1 60' b.
- 145' 100* $ A i 150' c.
- 145' 190' 1 A 1 265*
d.
- 145' 290' 1 A 1 330' 0706120107 07060D PDH ADOCK 0D0004D0 P
PDH RIVER BENO - UNIT 1 3/4 6-24
ATTACHMENT 2 CULF STATES UTILITIES COMPANY RIVER BEND STATION DOCKET 50-458/ LICENSE NO. NPF-47 MAIN STEAM TUNNEL AREA TEMPERATURE MONITORING LICENSING DOCUMENT INVOLVED:
TECHNICAL SPECIFICATIONS ITEM Table 3.7.8-1 PACE:
3/4 7-33 REASON FOR REQUEST Temperatures in the main steam tunnel (zone AB-114-2) have apprgached and exceeded the Technical Specification temperature limit of 122 F on numerous occasions during normal power operation.
Special Reports (RBC-22779 dated 12/11/85, RBG-23302 dated 3/10/86 and RBG-24271 dated 8/28/86) have been previously submitted. The Special Reports inform the NRC when safety related equipment has been subjected to temperatures in excess of their environmental qualification temperatures. Continued exposure to excessive temperatures in the main steam tunnel may degrade equipment and impact its' OPERABILITY in a post Loss of Coolant Accident (LOCA) environment.
i To avoid the hardship of preparing Special Reports and performing analyses on the effects of increased temperatures on equipment operability during normal plant operatfon, thig proposed change increases the temperature limit from 122 F to 135 F.
This temperature is sufficient to remain above operating temperatures experienced at River Band Station during normal plant operation and will preclude frequent entry into Technical Specification Action Statement 3.7.8.a or b.
DESCRIPTION Hiver Bend Station (RBS) Technical Specification 3/4.7.8 Area Temperature Monitoring, currently requires the main steam tunnel - north area temperature be maintained at less than or equal to 122 degrees F.
This proposed change would revise the area temperature,P to 135 F.ig Table limit 3.7.8-1, Area Temperature Monitoring, Item 1.1 from 122 As stated in the Bases for Technical Specification 3/4.7.8 the area temperature limitations ensure that safety-related equipment will not be subjected to temperatures in excess of their environmental qualification temperatures. Exposure to excessive temperatures may degrade equipment and could impact its OPERABILITY in a post LOCA environment.
The most limiting condition analyzed in the Safety Analysis in that for the main steam line break outside containment. This proposed change has no impact on the results of this analysis. Additionally, the maximum temperature and pressure used in the environmental qualification for all equipment in the main steam tunnel-north area are not impacted by this I
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f proposed change. Therefore, the equipment qualification of the affected equipment remains enveloped by the previous analyses. Additionally, the qualified lifes of this equipment have been revised to reflect the 4
proposed normal operating temperature.
The most limiting piece of equips.ent has a reduction in qualified life from 5 years to 4 years, well within the normal fuel cycle (18 months) time frame.
The Environmental Qualification Maintenance and Surveillance Requirements (EQMSR's) have also been updated to reflect the shorter qualified lifes and maintenance intervals.
Therefore, changing the main steam tunnel-north technical specification temperature limit from 122 F to 135 F will allow increased flexibility of plant operations while staying within the assumptions of the Safety j
Analysis.
SIGNIFICANT llAZARDS CONSIDERATION
}
As discussed in 10CFR50.92, the following discussions are provided to the NRC Staff in support of "no significant hazards considerations".
1.
No significant increase in the probability or the consequences of an accident previously evaluated results from this change because i
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The maximum temperature and pressure used in the qualification of equipment in the main steam tunnel-north is not affected by revising the maximum temperature to 135"F.
Therefore, the equipment remains within the previously analyzed regions and does not change the results as identified in the Safety Analysis for the main steam line break outside containment.
t 2.
Thin change would not create the possibility of a new or different kind of accident from any accident previously evaluated because:
}
No new equipment, or control logic changes have been added or altered. Reviews have been performed to ensure that existing design of equipment and structures can withstand the h1Rher normal l
operating temperatures. Equipment qualification and qualified life of equipment han been revised au necennary.
A review of the accident analysis indicatna that the peak temperature and prennure used for equipment qualification are not changed by the propoced amendment.
4 3.
This change would not involve a significant reduction in the margin j
of safety becauaer l
The proposed change does not affect the performance requirements contained in the Technical Specification 1.imiting conditions for Operation.
The peak temperature and presnure used in the qualification of equipment in the rain steam tunnel-north in not j
af fected by revining the technical specification temperature limit to 135 F.
Therefore, the margin of nnfety han not been nignificantly decreased.
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The proposed amendment, as discussed above, has not changed the system
- design, function or operation contained in the FSAR and therefore, will not increase the probability or the consequences of a previously evaluated event and will not create a new or different event. Also, the results of the change are clearly within all acceptable criteria with respect to system components and design requirements. As a result, the ability to perform as described in the FSAR is maintained.
Therefore, the proposed change does not significantly reduce the margin of safety.
GSU proposes that no significant hazards are involved.
REVISED TECHNICAL SPECIFICATION The requested revision is provided in the Enclosure.
SCHEDULE FOR ATTAINING COMPLIANCE As indicated above, River Bend Station is currently in compliance with the applicable Technical Specification.
NOTIFICATION OF STATE PERSONNEL A copy of the amendment application and this submittal has been provided to the State of Louisiana. Department of Environmental Quality - Nuclear Energy Division.
ENVIRONMENTAL IMPACT APPRAISAL Revision of this Technical Specification does not result in an environmental impact beyond that previously analyzed.
Therefore, approval of this amendment does not result in a significant environmental impact nor does it change any previous environmental impact statements for River Bend Station.
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TA8LE 3.7.8-1 AREA TEMPERATURE MONITORING AREA TEMPERATURE LIMIT (*F) 1.
Auxiliary 8uildina a.
LPCS area 122 b.
RHR A pump room 122 c.
RCIC pump room 122 d.
RHR 8 pump room 122 e.
RHR C pump room 122 f.
HPCS pump room 122 g.
MCC area (West) 112 h.
MCC area (East) 116 l
1.
Main steam tunnel (north)
-4deH 135 j.
Standby gas treatment rooms 122 k.
Annulus mixing fan area 122 1.
RHR Hx Area (West) 122 m.
Holst Area 122 n.
RHR Hx Area (East) 122 o.
HPCS Hatch Area 122 p.
RPCCW Area 122 q.
Elevator Room 122 r.
RPCCW Area 122 s
RHR Equip. Removal Cubicles 122 2.
Diesel Generator Control Rooms a.
Olesel Generator 1A 104 b.
Diesel Generator 18 104 c.
Diesel Generator 1C 104 3.
Control 8uildina a.
Standby switchgear room 1A 104 b.
Standby switchgear room 18 104 c.
Olvision I battery room 90 d.
Division !! battery room 90 e.
Division !!! battery room 90 f.
Inverter 1A room 104 g.
Inverter 18 room 104 h.
Inverter 1C room 104 RIVER BENO - UNIT 1 3/4 7-33
ATTACHMENT 3 CULF STATES UTILITIES COMPANY RIVER BEND STATION DOCKET 50-458/ LICENSE NO. NPF-47 MAIN STEAM TUNNEL TEMPERATURE ISOLATION ACTUATION INSTRUMENTATION SETPOINTS LICENSING DOCUMENT INVOLVED:
TECHNICAL SPECIFICATIONS ITEM: Table 3.3.2-2 PAGES: 3/4 3-19 3-20 3-21 3-22 REASON FOR REQUEST Several modifications have been performed in the past to maintain the Main Steam Tunnel (MST) temperatures as low as practicable during full power operation. These included increasing the air handling capacity of the unit coolers and the addition of insulation to main steam, feedwater and drain lines in the MST.
However, MST temperatures continue to remain high causing continuous high temperature alarms (based on a 5 gpm leakage rate) and increasing the likelihood of unnecessary Reactor Water Cleanup System (RWCU), Reactor Core Isolation Cooling System (RCIC) and Main Steam Line (MSL) isolations.
The proposed change increases the trip setpoints and allowable values of the main steam tunnel ambient and ventilation differential temperatures used for isolation of the main steam lines, RWCU and RCIC systems to decrease the likelihood of unnecessary isolations of these systems.
The proposed changes involve the increase of trip setpoints and allowable values in thet
- 1) main steam tunnel-south, high area temperature, for MSL isolation logic from 142 F and 145.3 F to 148 F and 151.3 F.
- 2) main steam tunnel-north, high area temperature, for MSL isojation,RWCUisolation,andRCICisolationfrom135Fand142.5F to 141 F and 148.5 F, and 3) main steam tunnel high differential temperature for MSL isolation, RWCU isolation and RCIC isolation from 51 F and 55 F to 57 F and 61 F.
DESCRIPTION Technical Specification Table 3.3.2-2, Isolation Actuation Instrumentation, lists the trip setpoints and allowable values for Leak Detection System (LDS) instrumentation used to mitigate the consequences of accidents. The bases for Technical Specification 3/4.3.2 states that where only the high or low end of the setpoint setting has a direct bearing on safety are established at a level away from the normal operating range to prevent inadvertent actuation of the systems involved. This statement is applicable to the main steam tunnel ambient and differential temperature setpoint proposed changes.
High ambient temperature in the MST and pipe routing areas in the Turbine Building, in which steam lines are located outside containment, could indicate a leak in a steam line.
Such a leak may also be indicated by high differential temperature between the outlet and inlet ventilation air ducts for these areas. A high ambient or differential temperature condition, sensed by any one of the temperature monitors (dual element thermocouples), results in tripping that monitor's associated channel.
These monitors provide alarm, indication and recording in the Main Control Room, and trip the isolation logic to close selected isolation valves (e.g.,
MSIV and MSL drain isolation valves, RWCU system isolation valves, and the RCIC system isolation valves). The temperature trip setpoints are calculated based on a 25 gpm leakage rate existing for one hour and are a function of room size, ventilation provided, and initial room temperature.
Diversity of MSL isolation initiation signals is provided by the MSL high flow monitors.
For the most limiting accident for offsite doses (MSL break outside containment) the main steam line high flow monitors are the primary method of isolation assumed in the Safety Analysis.
The current MST leak detection setpoints are based on an initial temperature equivalent to the predicted normal average temperature in the area (105 F North-MST, 130 F South-MST),
the type of ventilation supplied to the area, and a 25 gpm steam leakage rate for one hour. The leak rate was based on the Nuclear Steam Supply System (NSSS) vendor, General Electric (GE),
recommendation that the temperature trip setpoints be predicted on an equipment area temperature rise equivalent to a 25 gpm steam leakage rate for system isolation (ref. GE Design Specification Data Sheet 22A3735AF). The criterion for establishing the unidentified leakage rate of 25 gpm was based upon the makeup capability of the RCIC system and is independent of the feedwater system, normal a-c power, and the emergency core cooling systems. However, in the limiting transient for the RCIC system (Loss of Feedwater Transient),
RCIC will be initiated on Reactor water level 2 and inject water into the RPV sufficient to assure that level 1 is not reached, even in conjunction with a total system leakage of approximately 40 gpm.
The revised setpoints have the same bases as the current setpoints with the exception that the initial MST temperature is equal to the originally predicted normal maximum temperature expected in the area (122 F North-MST, 140 F South-MST).
This higher temperature is calculated with service water being at its design maximum temperature of 95 F.
The calculated temperature rise from a 25 gpm leak in the MST at this higher initial temperature yields a higher analytical limit and hence, trip setpoint.
In the case where ambient temperatures have a seasonal variation, there must be a trade off between the conservatism of the instrument setpoint and spurious isolation probability.
These proposed setpoints are calculated to prevent unnecessary or inadvertent isolations yet maintain the margin of safety as defined in the Technical Specification bases.
Increasing the trip setpoints for MST temperature monitoring will have minimal impact on the ability of the LDS to automatically isolate a small leak.
-.. - - ~_- -
i M5T temperature records were reviewed during the months of December 1986, January and February 1987. This review indicated that during full power operation the north and south ends of the MST rarely fell below an average temperature of 105 F.
At this initial temperature, a leak rate of less than 32 gpm for one hour would be required to reach the proposed area temperature isolation trip setpoints in both of these areas.
For offsite doses, this event is still bounded by the design basis accident of a main steam line circumferential break outside containment.
SIGNIFICANT HAZARDS CONSIDERATION As discussed in 10CFR50.92, the following discussions are provided to the NRC Staff in support of "no significant hazards considerations".
1.
No significant increase in the probability or the consequences of an accident previously evaluated results from this change because:
The temperature setpoints are predicted on an equipment area temperature rise equivalent to a 25 gpm steam leakage rate.
The n,
proposed change involved is that the initial area temperature used in the setpoint calculation is now the originally predicted maximum y
normal operating temperature instead of the predicted average normal operating temperature.
This will reduce the ability of the temperature monitors to isolate a 25 gpm leak during the winter months but, as discussed above, it will also reduce the likelihood of spurious isolations during normal full power operation in the summer months. Considering the above, and the fact that the current temperature monitor setpoint has a high chance of inadvertent MSIV, RCIC' or RWCU isolations, this change will not result in a
significant or unwarranted increase in the probability or consequences of an accident. This change is consistent with the original design basis in that the isolation trip setpoints be based upon an area temperature rise equivalent to RCPB leakage into the monitored areas of 25 gpm. The results of the MSL break outside containment analysis have not been altered with regard to peak temperature, pressure or offsite doses and remain the bounding case for offsite doses.
2.
This change would not create the possibility of a new or different kind of accident from any accident previously evaluated because:
No hardware changes are involved and the system function and purpose remain unchanged. The proposed isolation setpoints will still isolate the affected systems prior to crack propogation as postulated in the analysis.
3.
This change would not involve a significant reduction in the margin of safety because:
j This change is consistent with the original design basis and the
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Technical Specification basis. The effectiveness of the temperature monitoring instrumentation to mitigate the consequences of an accident (i.e. automatically isolate a small leak at an early stage) has not been significantly reduced.
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A degree of area temperature monitoring ability is sacrificed for increased plant availability. However, inadvertent and unnecessary MSIV isolations impose plant transients which create a safety risk in and of themselves. This change is an appropriate compromise between the two.
The main steam line circumferential break oustide containment still bounds the offsite dose calculations.
Therefore, the margin of safety has not been significantly reduced.
Additionally, temperature leak detection is a backup to the high flow leak detection system used in the main steam line break outside containment analyses.
Since the proposed amendment does not change any previously revised and approved description or. safety analysis as described in the FSAR nor does it create the possibility of a new or different type of accident or significantly reduce the margin of safety, GSU proposes that no significant hazards are involved.
REVISED TECHNICAL SPECIFICATION The requested revision is provided in the Enclosure.
SCHEDULE FOR ATTAINING COMPLIANCE As indicated above, River Bend Station is currently in compliance with the applicable Technical Specification.
NOTIFICATION OF STATE PERSONNEL A copy of submittal has been provided to the State of Louisiana, Department of Environmental Quality - Nuclear Energy Division.
ENVIRONMENTAL IMPACT APPRAISAL Revision of this Technical Specification does not result in an environmental impact beyond that previously analyzed.
Therefore, approval of this amendment does not result in a
signifie: ant environmental impact nor does it change any previous environmental impact statements for River Bend Station, l
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TABLE 3.3.2-2 i5
' ISOLATION ACTUATION INSTRUMENTATION SETPOINTS iM i=
ALLOWABLE lg TRIP FUNCT'10N TRIP SETPOINT VALUE lE 1.
PRIMARY CONTAINMENT ISOLATION a.
,e l5 Low Low, Level 2 1-43 inches
- 1-47 inches w
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Drywell Pressure - High 5 1.68 psig i 1.88 psig c.
Containment Purge Isolation Radiation - High 1 1.3 R/hr 5 1.57 R/hr l
2.
MAIN STEAM LINE ISOLATION a.
]4 Low Low Low, Level 1 1-143 inches
- l-147 inches j=
b.
Main Steam Line Radiation - High 1 3.0 x full power background i 3.6 x full power jy background
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Main Steam Line Pressure - Low 1 849 psig 1 837 psig j
d.
Main Steam Line Flow - High 1 173** psid i 178** psid e.
Condenser Vacuum - Low 3 8.5 inches Hg.
1 7.6 inches Hg.
n vacuum vacuum i
f.
Main Steam Line Tunnel Temperature - High 5 125"r 141 F
$ ;;;.;=T 148.5 F 1
g.
Main Steam Line Tunnel j
A Temperature - High 1 64ap_
- 57. F g.55aP-61 F p o r,t.,,,d
}p RECEIVED
[ -'7 6toER #
q JUN 241986 Jul 8 se
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. TABLE 3.3.2-2 (Continued)
ISOLATION ACTUATION INSTRUMENTATION SETPOINTS
- 9
!m ALLOWABLE TRIP FUNCTION TRIP SETPOINT VALUE i'
2.
MAIN STEAM LINE ISOLATION (Cont'd) e5 h.
Main Steam Line Area Temperature - High (Turbine Building) o o
- 1. Main Steam Tunnel Area (EI. 95')
7 ::cor 148,F
< ;;;,;=r 151 3 F
< :::ar 148 g
1
- 2. Main Steam Tunnel Area (E1. 114')
F 7 ;;;,3=7 151.3 F i
- 3. Main Steam Line Turbine Shield Wall 7 108'F 7 111.3*F (1
- 4. MSL Moisture Separator and Reheater i 126 F 7 130*F Area 1
l 3.
SECONDARY CONTAINMENT ISOLATION N[
a.
l Low Low Level 2 1 - 43 inches
- 1 - 47 inches.
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Drywell Pressure - High 1 1.68 psig i 1.88 psig
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c.
Fuel Building Ventilation l
Exhaust Radiation - High i
I 1RMS*RESA
< 1.82 x 108 pCi/sec
< 2.18 x 108 pCi/sec 1RMS*RE5B
?5.88x104 pCi/cc
?7.05x104 pCi/cc j
d.
Reactor Building Annulus Ventilation Exhaust Radiation - High 5 4.32 x 10 5 pCi/cc
$ 5.19 x 10 5 pCi/cc j
4.
REACTOR WATER CLEANUP SYSTEM ISOLATION a.
A Flow - High 1 55 gpm 5 62.1 gpm jg
- G b.
A Flow Timer 5 45 seconds 1 47 seconds
- o iR c.
Equipment Area Temperature - High l$
- 1. Heat Exchanger Room
'$ 98.5'F i 101.5'F i2
- 2. Pump Rooms A & 8
< 165*F
< 169.5*F
- 3. Valve Nest Room i 110*F 7 114.5*F
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- 4. Demineralizer Rooms 1 and 2 7 110*F 7 114.5"F
- 5. Receiving Tank Room 3110*F 3114.5*F l
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1 TABLE 3.3.2-2 (Continued)
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ISOLATION ACTUATION INSTRUMENTATION SETPOINTS E
ALLOWABLE co
. g TRIP FUNCTION TRIP SETPOINT VALUE I
4.
REACTOR WATER CLEANUP SYSTEM ISOLATION (Cont'd) d.
Equipment Area a Temperature - High
.E 1.
Heat Exchanger Room 1 33*F S 36.5*F Q
2.
Pump Rooms A and 8 5 78'F i 82*F 3.
Valve Nest Room 5 46*F i 49.5'F g
4.
Demineralizer Rooms 1 and 2
< 46*F
< 49.5'F i
5.
Receiving Tank Room 546*F 549.5'F e.
Low Low Level 2 1 - 43 inches
- 1 - 47 inches f.
Main Steam Line Tunnel o
Ambient Temperature - High 5 125 I I41 F 1 10 ;"i 148 F g.
Main Steam Line Tunnel o
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A Temperature - High in S7 F 1-55aF-61 F w
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SLCS Initiation NA NA U
5.
REACTOR CORE ISOLATION COOLING SYSTEM ISOLATION I
a.
RCIC Steam Line Flow - High 1 222" H 0**
1 230.5" H 0**
j 2
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RCIC Steam Line Flow - High Timer 1 3 seconds 5 13 seconds c.
RCIC Steam Supply Pressure - Low 1 60 psig 1 55 psig d.
RCIC Turbine Exhaust Diaphragm Pressure - High 1 10 psig i 20 psig l
e.
RCIC Equipment Room Ambient Temperature - High
_ $ 182*F
$ 186.4*F f.
RCIC Equipment Room a Temperature -
1 96*F i 99'F High
TABLE 3.3.2-2 (Continued) h ISOLATION ACTUATION INSTRUMENTATION SETPOINTS E
ALLOWABLE
,g TRIP FUNCTION TRIP SETPOINT VALUE i
o 5.
REACTOR CORE ISOLATION COOLING SYSTEM ISOLATION (Cont'd) g.
Main Steam Line Tunnel Ambient c
h Temperature - High
$ 125*" 141 F
$ 102.5*." 148.5 F l
h.
Main Steam Line Tunnel l
A Temperature - High 5-64aF-57 F 5-66ap.
61 F 1.
Main Steam Line Tunnel Temperature Timer 0 seconds NA J.
RHR Equipment Room Ambient Temparature - High 5 117'F i 121.1*F R
k.
RHR Equipment Room y
A Temperature - High 5 29'F 1 33.6*F m"
1.
RHR/RCIC Steam Line Flow - High 1 156" Hz **
1 164.5" Hz **
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Drywell Pressure - High 5 1.68 psig 5 1.88 psig
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Manual Initiation NA NA 6.
RHR SYSTEM ISOLATION a.
RHR Equipment Area Ambient Temperature - High 5 117'F 5 121.1*F b.
RHR Equipment Area A Temperature -
l High 3 29'F 1 33.6*F c.
. Low Level 3 1 9.7 inches
- 1 8.7 inches d.
Low Low Low Level 1 1 - 381 inches
- 1 - 147 inches i
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