ML20212Q715

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Amend 27 to License NPF-18,incorporating Mod of Automatic Depressurization Sys Logic,Per License Condition 2.C.(18)(d)(i)
ML20212Q715
Person / Time
Site: LaSalle Constellation icon.png
Issue date: 08/29/1986
From: Adensam E
Office of Nuclear Reactor Regulation
To:
Shared Package
ML20212Q713 List:
References
NUDOCS 8609080015
Download: ML20212Q715 (13)
v • d • e


Text

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UNITED STATES

!" N,E NUCLEAR REGULATORY COMMISSION

, E WASHINGTON, D. C. 20555

%*****/ COMMONWEALTH EDIS0N COMPANY l

DOCKET NO. 50-374 LA SALLE COUNTY STATION, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 27 License No. NPF-18

1. The Nuclear Regulatory Commission (the Commission or the NRC) has found that:

l l A. The application for amendment filed by the Commonwealth Edison Company (the licensee), dated July 3,1986, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's regulations set forth in 10 CFR Chapter I; B. ' The facility will operate in conformity with the applicatiors he provisions of the Act, and the regulations of the Comnission; C. There is reasonable assurance: (1) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations sat forth in 10 CFP Chapter I; D. The issuance of this anendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this anendment is in accordance with 10 CFR Part 51 of the Connission's regulations and all applicable requirements have been satisfied.

2. Accordinoly, the license is amended by changes to the Technical Specifica-tions as indicated in the enclosure to this license amendment and paragraph 2.C.(2) of the Facility Operating License No. NPF-18 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 27, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

$$ boo $

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3. This amendment is effective upon startup follnwing the first refueling.

FOR THE NUCLEAR.REGllt'ATORY COMISSION f& .k Elinor G. Adensam, Director

';=~

RWR Pro.iect Directorate No. 3 Division of BWR Licensing

Enclosure:

Chances to the Technical Specificatiens Date of Issuance: August 29, 1986

ENCLOSURE TO LICENSE AMENDMENT NO. 27 FACILITY OPERATING LICENSE NO. NPF-18 DOCKET NO. 50-374 Replace the followina pages of the Appendix "A" Technical Specifications with the enclosed pages. The revised pages are identified by Amendment number and contain a vertical line indicating the area of chanoe.

REMOVE INSERT 3/4 3-24 3/4 3-24 3/4 3-25 3/4 3-25 3/4 3-27 3/4 3-27 3/4 3-28 3/4 3-28 3/4 3-29 3/4 3-29 3/4 3-32 3/4 3-32 3/4 3-33 3/4 3-33 3/4 5-1 3/4 5-1 R 3/4 5-1 B 3/4 5-1 B 3/4 5-2 B 3/4 5-2

TABLE 3.3.3-1 g

y EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION

- APPLICABLE m MINIMUM OPERABLE

' CHANNELS PER TRIP OPERATIONAL FUNCTION (a) CONDITIONS ACTION b

TRIP FUNCTION N A. DIVISION I TRIP SYSTEM

1. RHR-A (LPCI MODE) & LPCS SYSTEM
a. Reactor Vessel Water Level - Low Low Low, level 1 2(b) 1, 2, 3, 4*, 5* 30 2(b) 1, 2, 3 30
b. Drywell Pressure - High LPCS Pump Discharge Flow-Low (Bypass) 1 1, 2, 3, 4*, 5* 31
c.
d. LPCS and LPCI A Injection Valve Injection Line 1/ Valve 1,2,3 32 4*, 5* 33 g Pressure-Low (Permissive) 2 1,2,3 38
e. LPCS and LPCI A Injection Valve Reactor w

Pressure-Low (Permissive) 4*, 5* 33 J,

LPCI Pump A Start Time Delay Relay 1 1, 2, 3, 4*, 5* 32 f.

LPCI Pump A Discharge Flow-Low (Bypass) 1 1, 2, 3, 4*, 5* 31 g.

1/ division 1, 2, 3, 4*, 5* 34

h. Manual Initiation
2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "A"#

Reactor Vessel Water Level - Low Low Low, Level 1 2(b) 1, 2, 3 30

a. ,

coincident with 2(b) 1, 2, 3 30

b. Drywell Pressure - High 1 1,2,3 32 l
c. Initiation Timer Reactor Vessel Water Level - Low, Level 3 (Permissive) 1 1,2,3 32 k d.

1,2,3 32 LPCS Pump Discharge Pressure-High (Permissive) 2 h e.

2 1,2,3 32 k f. LPCI Pump A Discharge Pressure-High (Permissive) 1/ division 1,2,3 34 y g. Manual Initiation 1 1,2,3 32 y h. Drywell Pressure Bypass Timer 1/ division 1, 2, 3 34

i. Manual Inhibit

I g TABLE 3.3.3-1 (Continued) ,

$ EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION i E m

MINIMUM OPERABLE- APPLICABLE

' CHANNELS PER TRIP OPERATIONAL TRIP FUNCTION FUNCTION (a) CONDITIONS ACTION ,

N

. B. DIVISION 2 TRIP SYSTEM j 1. RHR B & C (LPCI MODE)

a. Reactor Vessel Water Level - Low, low Low, Level 1 2(b) 1, 2, 3, 4*, 5* 30
b. Drywell Pressure - High 2(b) 1, 2, 3 30
c. LPCI B and C Injection Valve Injection L;ne Pressure-Low 1/ valve 1,2,3 32 (Permissive) 4*, 5* 33

! t' d. LPCI Pump B Start Time Delay Relay 1 1, 2, 3, 4*, 5* 32

$ e. LPCI Pump Discharge Flow - Low (Bypass) 1/ pump 1, 2, 3, 4*, 5* 31 h f. Manual Initiation 1/ division 1, 2, 3, 4*, 5* 34 i g. LPCI B and C Injection Valve Reactor 2 1, 2, 3, 38

Pressure-Low (Permissive) 4*, 5* 33
2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "B"#
a. Reactor Vessel Water Level - Low Low Low, level 1 2(b) 1, 2, 3 30
coincident with
b. Drywell Pressure - High 2(b) 1, 2, 3 30
c. Initiation Timer 1 1,2,3 32 l
d. Reactor Vessel Water Level - Low, Level 3 (Permissive) 1 '1, 2, 3 32 l @ e. LPCI Pump B and C Discharge Pressure - High (Permissive) 2/ pump 1,2,3 32 a

c.

g f. Manual Initiation 1/ division 1, 2, 3 34 i

5 g. Drywell Pressure Bypas,s Timer 1 1,2,3 32 z

i

h. Manual Inhibit 1/ division 1,2,3 34 5

4-*

TABLE 3.3.3-1 (Continued) i~

EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION ACTION

. - ACTION 30 - With the number of OPERABLE channels less th'an required by the

! Minimum OPERABLE Channels per Trip Function requirement:

a. With one channel inoperable, place the inoperable channel in the tripped condition within one hour
  • or declare the
associated system irsoperable.
b. With more than one channel inoperable, declare the associated system inoperable.

t ACTION 31 - With the number of OPERABLE channels less than required by the Minimum OPERABLE channels per Trip Function, place the inoperable

! channel in the tripped condition within one hour; restore the

inoperable channel to OPERABLE status within 7 days or declare '

l the associated system inoperable.

ACTION 32 - With the number of OPERABLE channels less than required by the Minimum OPERABLE Channels per Trip Function requirement, declare the associated ADS trip system or ECCS inoperable.

ACTION 33 - With the number of OPERABLE channels less than the Minimum

OPERABLE Channels per Trip Function requirement, place the i inoperable channel in the tripped condition within one hour.

l ACTION 34 - With the number of OPERABLE channels less than required by the Minimum OPERABLE Channels per Trip Function requirement, restore the inoperable channel to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or 4

declare the associated ADS trip system or ECCS inoperable. l-ACTION 35 - With the number of OPERABLE channels less than required by the

Minimum OPERABLE Channels per Trip Function requirement 1

i

a. For one trip system, place that trip system in the tripped condition within one hour
b. For both trip systems, declare the HPCS system inoperable.

ACTION 36 - With the number of OPERABLE channels less than required by the Minimum OPERABLE Channels per Trip Function requirement, place at least one inoperable channel in the tripped condition within one hour

ACTION 37 - With the number of OPERABLE instruments less than the Minimum OPERABLE INSTRUMENTS, place the inoperable instrument (s) in the tripped condition within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

! "The provisions of Specification 3.0.4 are not applicable. ,

LA SALLE - UNIT 2 3/4 3-27 Amendment No.27

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i .

6 r- TABLE 3.3.3-2 l $ EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION SETPOINTS t p

  • ALLOWABLE i ,.

' TRIP SETPOINT VALUE TRIP FUNCTION E

, Q A. DIVISION 1 TRIP SYSTEM f

l 1. 'RHR-A (LPCI MODE) AND LPCS SYSTEM i a. Reactor Vessel Water Level - Low Low Low, Level 1 >- 129 inches * >- 136 inches *

b. Drywell Pressure - High 5 1.69 psig {1.89psig l c. LPCS Pump Discharge Flow-Low > 750 gpm > 640 gpm
d. LPCS and LPCI A Injection Valve Injection Line- 500 psig 500 1 20 psig i Low Pressure Interlock
e. LPCS and LPCI A Injection Valve Reactor 500 psig 500 1 20 psig 4 w Pressure-Low Pressure Interlock
1 f. LPCI Pump A Start Time Delay Relay 5 5 seconds 5 6 seconds w g. LPCI Pump A Discharge Flow-Low > 1000 gpm > 550 gpm

! A h. Manual Initiation H.A. H.A.

co l 2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "A" l a. Reactor Vessel Water level - Low Low Low, Level 1 >- 129 inches * >- 136 inches
  • I b. Drywell Pressure - High 7 1.69 psig i 1.89 psig
c. Initiation Timer i 105 seconds 7 117 seconds l
d. Reactor Vessel Water Level-Low, level 3 5 12.5 inches
  • I 11 inches
  • i 146 psig, increasing i 136 psig, increasing

{ e. LPCS Pump Discharge Pressure-High i f. LPCI Pump A Discharge Pressure-High i 119 psig, increasing i 106 psig, increasing

! g. Manual Initiation H.A. H.A.

I h. Drywell Pressure Bypass Timer < 9.0 minutes Footnote (a)

! i. Manual Inhibit H.A. N.A.

'l E E

.ii-5 (a) The sum of the time delays associated with the ADS initiation timer and the drywell pressure bypass timer z shall be less than or equal to 687 seconds.

,  ?

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j '.  :

g TABLE 3.3.3-2 (Continued)

% EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION SETPOINTS m

ALLOWABLE

TRIP FUNCTION TRIP SETPOINT VALUE

. z j M B. DIVISION 2 TRIP SYSTEM

! N j 1. RHR B AND C (LPCI MODE)

a. Reactor Vessel Water Level - Low Low Low, Level 1 >- 129 inches *
b. Drywell Pressure - High >- 136 inches
  • 7 1.69 psig i 1.89 psig
c. LPCI B and C Injection Valve Injection Line 500 psig 500 + 20 psig 4

Low Pressure Interlock

d. LPCI Pump B Start Time Delay Relay
e. LPCI Pump Discharge Flow-Low $ 5 seconds 5 6 seconds

> 1000 gpm > 550 gpm

f. Manual Initiation N. A. H.A.

', R

g. LPCI B and C Injection Valve Reactor 500 psig 500 + 20 psig Pressure-Low Pressure Interlock -

i i

Y m

1 LD

2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "B" I a. Reactor Vessel Water Level - Low Low Low, Level 1 >- 129 inches * >- 136 inches
  • l b. Drywell Pressure - High 7 1.69 psig 7 1.89 psig
c. Initiation Timer 7 105 seconds 7 117 seconds
d. Reactor Vessel Water Level-Low, Level 3 5 12.5 inches
  • l
e. 'I 11 inches
  • 1 LPCI Pump B and C Discharge Pressure-High 5 119 psig, increasing i 106 psig,. increasing
f. Manual Initiation N.A. H.A.

, g. Drywell Pressure Bypass Timer < 9.0 minutes

! h. Manual Inhibit Footnote (a)

R. A. N.A.

i I

i' C

e E (a) The sum of the time delays associated with the ADS initiation timer and the drywell pressure

! R bypass timer shall be less than or equal to 687 seconds.

i  ?+

z i

i

g TABLE 4.3.3.1-1 g EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION SURVEILLANCE REQUIREMENTS l-CHANNEL OPERATIONAL CHANNEL FUNCTIONf'. CHANNEL CONDITIONS FOR WHICH E TRIP FUNCTION CHECK TEST CALIBRATION SURVEILLANCE REQUIRED Z

w A. DIVISION I TRIP SYSTEM

1. RHR-A (LPCI MODE) AND LPCS SYSTEM
a. Reactor Vessel Water Level -

Low Low Low, Level 1 NA M R 1, 2, 3, 4*, 5*

b. Drywell Prassure - High NA M Q 1, 2, 3
c. LPCS Pump Discharge Flow-Low NA M Q 1, 2, 3, 4* , 5*
d. LPCS and LPCI A Injection Valve Injection Line Pressure Low w Interlock NA M R 1, 2, 3, 4* , 5*

1 e. LPCS and LCPI A Injection Valve w Reactor Pressure Low Interlock NA M R 1, 2, 3, 4*, 5*

J, f. LPCI Pump A Start Time Delay N Relay NA M Q 1, 2, 3, 4*, 5*

g. LPCI Pump A Flow-Low NA M Q 1, 2, 3, 4*, 5*
h. Manual Initiation NA R NA 1, 2, 3, 4*, 5*
2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "A"#
a. Reactor Vessel Water Level -

Low Low Low, Level 1 NA M R 1,2,3

b. Drywell Pressure-High NA M Q 1,2,3
c. Initiation Timer NA M Q 1,2,3 l
d. Reactor Vessel Water Level -

Low, Level 3 NA M R 1, 2, 3

e. LPCS Pump Discharge y Pressure-High NA M Q 1, 2, 3 g f. LPCI Pump A Discharge

& Pressure-High NA M Q 1,2,3 g g. Manual Initiation NA R NA 1,2,3 r+ h. Drywell Pressure Bypass Timer NA M 1,2,3 Q

g

i. Manual Inhibit NA R NA 1,2,3

TABLE 4.3.3.1-1 (Continued) 9 hp EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION SURVEILLANCE R F

CHANNEL OPERATIONAL FUNCTIONAL CHANNEL CONDITIONS FOR WHICH

' CHANNEL TEST CALIBRATION SURVEILLANCE REQUIRED CHECK E TRIP FUNCTION Z

m B. DIVISION 2 TRIP SYSTEM

1. RHR B AND C (LPCI MODE)
a. Reactor Vessel Water Level - R 1, 2, 3, 4*, 5*

Low Low Low, Level 1 NA M M Q 1,2,3 Drywell Pressure - High NA b.

c. LPCI B and C Injection Valve Injection Line Pressure Low R 1, 2, 3, 4*, 5*

NA M Interlock R$ d. LPCI Pump B Start Time Delay Q 1, 2, 3, 4*, 5*

M

  • Relay NA NA M Q 1, 2, 3, 4* , 5*

y e. LPCI Pump Discharge Flow-Low NA R NA 1, 2, 3, 4*, 5*

$ f. Manual Initiation

g. LPCI B and C Injection Valve NA M R 1, 2, 3, 4*, 5*

Reactor Pressure Low Interlock

2. AUTOMATIC DEPRESSURIZATION SYSTEM TRIP SYSTEM "B"#
a. Reactor Vessel Water Level - ~

M R 1,2,3 Low Low Low, Level 1 NA 1,2,3 NA M Q

' b. Drywell Pressure-High 1,2,3 l NA M Q

c. Initiation Timer
d. Reactor Vessel Water Level - M R 1,2,3 Low, Level 3 NA y e. LPCI Pump B and C Discharge Q 1, 2, 3 NA M g Pressure-High NA R NA 1,2,3 l g f. Manual Initiation 1,2,3 NA M Q j g g. Drywell Pressure Bypass Timer R NA 1,2,3 NA 2
h. Manual Inhibit

?

i l

l 3/4.5 EMERGENCY CORE COOLING SYSTEMS 3/4.5.1 ECCS - OPERATING LIMITING CONDITION FOR OPERATION 3.5.1 ECCS divisions 1, 2 and 3 shall be OPERABLE with:

a. ECCS division 1 consisting of: -
1. The OPERABLE low pressure core spray (LPCS) system with a flow path capable of taking suction from the suppression chamber and transferring the water through the spray sparger to the reactor vessel.
2. The OPERABLE low pressure coolant injecticn (LPCI) subsystem "A" of the RHR system with a flow path capable of taking suction from the suppression chamber and transferring the water to the reactor vessel.
3. At least 6 OPERABLE ** ADS valves. l
b. ECCS division 2 consisting of:

i

1. The OPERABLE low pressure coolant injection (LPCI) subsystems "B" and "C" of the RHR system, each with a flow path capable of taking suction from the suppression chamber and transferring the water to the reactor vessel.
2. At least 6 OPERABLE ** ADS valves.

l

c. ECCS division 3 consisting of the OPERABLE high pressure core spray
(HPCS) " stem with a flow path capable of taking suction from the j suppression chamber and transfarring the water through the spray sparger to the reactor vessel.

ADPLICABILITY: OPERATIONAL CONDITION 1, 2*# and 3*.

  • The ADS is not required to be OPERABLE when reactor steam dome pressure is less than or equal to 122 psig.
    • See Specification 3.3.3 for trip system operability.
  1. See Special Test Exception 3.10.6.

LA SALLE - UNIT 2 3/4 5-1 Amendment No.27

4 I

l' 3/4.5 EMERGENCY CORE COOLING SYSTEM l

BASES '

3/4.5.1 and 3/4.5.2 ECCS - OPERATING and SHUTDOWN  :

ECCS Division 1 consists of the low pressure core spray system, low pres-  :

, sure coolant injection subsystem "A" of the RHR system, and the automatic de-pressurization system (ADS) as actuated by ADS trip system "A". ECCS Division 2 consists of low pressure coolant injection subsystems "B"and "C" of the RHR sys- ,

] tem and the automatic depressurization system as actuated by ADS trip system "B". '

The low pressure core spray (LPCS) system is provided to assure that the core is adequately cooled following a loss-of-coolant accident and provides

~

adequate core cooling capacity for all break sizes up to and including the

double-ended reactor recirculation line break, and for transients or smaller l l breaks following depressurization by the ADS.

The LPCS is a primary source of emergency core cooling after the reactor vessel is depressurized and a source for flooding of the core in case of

, accidental draining.

! The surveillance requirements provide adequate assurance that the LPCS sys-tem will be OPERABLE when required. Although all active components are testable and full flow can be demonstrated by recirculation through a test loop during reactor operation, a complete functional test requires reactor shutdown. The pump discharge piping is maintained full to prevent water hammer damage to piping and to start cooling at the earliest moment.

The low pressure coolant injection (LPCI) mode of the RHR system is pro-

, vided to assure that the core is adequately cooled following a loss-of-coolant accident. Three subsystems, each with one pump, provide adequate core flooding 1 for all break sizes up to and including the double-ended reactor recirculation 4

line break, and for transients or small breaks following depressurization by the l ADS.

The surveillance requirements provide. adequate assurance that the LPCI system will be OPERABLE when required. Although all active components are l testable and full flow can be demonstrated by recirculation through a test i loop during reactor operation, a complete functional test. requires reactor

! shutdown. The pump discharge piping is maintained full to prevent water hammer damage to piping and to start cooling at the earliest moment.

ECCS Division 3 consists of the high pressure core spray system. The high pressure core spray (HPCS) system is provided to assure that the reactor core is adequately cooled to limit fuel clad temperature in the event of a small break in the reactor coolant system and loss of coolant which does not result in rapid depressurization of the reactor vessel. The HPCS system permits the reactor to be shut down while maintaining sufficient reactor
vessel water level inventory until the vessel is depressurized. The HPCS
system operates over a range of 1160 psid, differential pressure between
reactor vessel and HPCS suction source, to O psid.

4 The capacity of the HPCS system is selected to provide the required core cooling. The HPCS pump is designed to deliver greater than or equal to 516/1550/6200 gpm at differential pressures of 1160/1130/200 psid. Initially,

, water from the condensate storage tank is used instead of injecting water from 1

t j LA SALLE - UNIT 2 B 3/4 5-1 Amendment No. 27

- - - , , . - ----,_n , - , - - , . . , - - _ - - , , . - - - ~ . _ . . . - . . . . , _ _ - - - - . _ - - - - - - - - - . - - - , , - - - - - - - . - - . - - - -

EMERGENCY CORE COOLING SYSTEMS BASES ECCS-0PERATING and SHUTDOWN (Continued) the suppression pool into the reactor, but no credit is taken in the hazards analyses for the condensate storage tank water.

With the HPCS system inoperable, adequate core cooling is assured by the OPERABILITY of the redundant and diversified automatic depressurization system and both the LPCS and LPCI systems. In addition, the reactor core isolation cooling (RCIC) system, aesystem for which no credit is taken in the hazards analysis, will automatically provide makeup at reactor operating pressures on a reactor low water level condition. The HPCS out-of-service period of 14 days is based on the demonstrated OPERABILITY of redundant and diversified low pressure core cooling systems.

The surveillance requirements provide adequate assurance that the HPCS system will be OPERABLE when required. Although all active components are testable and full flow can be denonstrated by recirculation through a test loop during reactor operation, a complete functional test with reactor vessel injection requires reactor shutdown. The pump discharge piping is maintained full to prevent water hammer damage and to provide cooling at the earliest moment.

Upon failure of the HPCS system to function properly, if required, the l automatic depressurization system (ADS) automatically causes selected safety-relief valves to open, depressurizing the reactor se that flow from the low pressure core cooling systems can enter the core in time to limit fuel cladding temperature to less than 2200*F. ADS is conservatively required to be OPERABLE whenever reactor vessel pressure exceeds 122 psig even though low pressure core cooling systems provide adequate core cooling up to 350 psig.

ADS automatically controls seven selected safety-relief valves. Six valves are required to be OPERABLE although the hazards analysis only takes credit for five valves. It is therefore appropriate to permit one of the required vahes to be out-of-service for up to 14 days without materially reducing system reliability.

j 3/4.5.3 SUPPRESSION CHAMBER The suppression chamber is also required to be OPERABLE as part of the ECCS to ensure that a sufficient supply of water is available to the HPCS, LPCS and l LPCI systems in the event of a LOCA. This limit on suppression chamber minimum water volume ensures that sufficient water is available to permit recirculation cooling flow to the core. The OPERABILITY of the suppression chamber in OPERATIONAL CONDITIONS 1, 2 or 3 is required by Specification 3.6.2.1.

Repair work might require making the suppression chamber inoperable.

This specification will permit those repairs to be made and at the same time give assurance that the irradiated fuel has an adequate cooling water supply when the suppression chamber must be made inoperable, including draining, in OPERATIONAL CONDITION 4 or 5.

In OPERATIONAL CONDITION 4 and 5 the suppression chamber minimum required t

water volume is reduced because the reactor coolant is maintained at or below 200'F. Since pressure suppression is not required below 212 F, the minimum water volume is based on NPSH, recirculation volume, vortex prevention plus a 2'-4" safety margin for conservatism.

LA SALLE - UNIT 2 B 3/4 5-2 Amendment No. 27 1

_ _ _ _ __ _ __ ._______.- _-_. _ __ _. ._ _ _ _ _ _ _ _ . _ _ _ _ _ _ .

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