ML20072S050

Proposed Tech Specs Re Instrumentation That Initiates Primary Containment Isolation & Initiates or Controls Core & Containment Systems

ML20072S050
Person / Time
Site:	Pilgrim
Issue date:	09/06/1994
From:	BOSTON EDISON CO.
To:
Shared Package
ML20072S035	List: ML20072S033 ML20072S050
References
94-097, 94-97, NUDOCS 9409130402
Download: ML20072S050 (8)

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ATTACHMENT B BECO LETTER 94-097 AMENDED TECHNICAL SPECIFICATION PAGES PAGE

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PE(PS TABLE 3.2.A INSTRUMENTATION THAT INITIATES PRIMARY CONTAINMENT ISOLATION .

Operable Instrument channels Per Trip System (1)

Minimum Available Instrument Trio Level Settinn Action (2) 2(7) 2 Reactor Low Water Level 211.7" indicated level (3) A and D 1 1 Reactor High Pressure $76 psig D l 2 2 Reactor Low-Low Water Level at or above -46.3 in. A indicated level (4) 2 2 Reactor High Water Level $45.3" indicated level (5) B 2(7) 2 High Drywell Pressure 52.22 psig A 2 2 High Radiation Main Steam $7 times normal rated B Line Tunnel (9) full power background 2 2 Low Pressure Main Steam Line 2810 psig (8) B 2(6) 2 High Flow Main Steam Line $136% of rated steam flow B 2 2 Main Steam Line Tunnel Exhaust Duct High Temperature $170 F B 2 2 Turbine Basement Exhaust Duct High Temperature $150 F B 1 1 Reactor Cleanup System High Flow $300% of rated flow C 2 2 Reactor Cleanup System High Temperature $150 F C i

Revision 170 Amendment No. 86, 147, 150, 151 45

PNPS TABLE 3.2.B (Cont'd)

INSTRUMENTATION THAT INITIATES OR CONTROLS THE CORE AND CONTAINMENT COOLING SYSTEMS Minimum # of Operable Instrument Channels Per Trip System (1) Trin Function Trip Level Setting Remarks 2 High Drywell Pressure $2.22 psig 1. Initiates Core Spray; LPCI; HPCI.

2. In conjunction with Low-Low Reactor Water Level, 94.4 - 115.6 second time delay and LPCI or Core Spray pump running, initiates Auto Blowdown (ADS)

3. Initiates starting of Diesel Generators

4. In conjunction with Reactor Low Pressure initiates closure of HPCI vacuum breaker containment isolation valves.

1 Reactor Low Pressure 400 psig i 5 Permissive for Opening Core Spray and <

LPCI Admission valves.

1 Reactor Low Pressure 576 psig In conjunction with PCIS signal permits closure of RHR (LPCI) inj ection valves.

1 Reactor Low Pressure 400 psig i 5 In conjunction with Low-Low Reactor Water Level initiates Core Spray and LPCI.

2 Reactor Low Pressure 900 psig i 5 Prevents actuation of LPCI break detection circuit.

2 Reactor Low Pressure 80 psig i 5 Isolates HPCI and in conjunction with High Drywell Pressure initiates closure of HPCI vacuum breaker containment isolation valves.

Revision 170 Amendment No. 42--113, 148, 151 48

. BASES:

3.2 In addition to reactor protection instrumentation which initiates a reactor scram, protective instrumentation has been provided which initiates action to mitigate the consequences of accidents which are i beyond the operator's ability to control, or terminates operator errors l before they result in serious consequences. This set of specifications  !

provides the limiting conditions of operation for the primary system isolation function, initiation of the core cooling systems, control rod block, and standby gas treatment systems. The objectives of the Specifications are, (i) to assure the effectiveness of the protective 1 instrumentation when required by preserving its capability to tolerate a single failure of any component of such systems even during periods when portions of such systems are out of service for maintenance, and (ii) to prescribe the trip settings required to assure adequate performance.

When necessary, one channel may be made inoperable for brief intervals to conduct required functional tests and calibrations.

Some of the settings on the instrumentation that initiate or control core and containment cooling have tolerances explicitly stated where the  ;

high and low values are both critical and may have a substantial effect j on safety. The set points of other instrumentation, where only the high '

or low end of the setting has a direct bearing on safety, are chosen at a level away from the normal operating range to prevent inadvertent actuation of the safety system involved and exposure to abnormal situations.

Actuation of primary containment valves is initiated by protective instrumentation shown in Table 3.2.A which senses the conditions for which isolation is required. Such instrumentation must be available whenever primary containment integrity is required.

The instrumentation which initiates primary system isolation is connected in a dual bus arrangement.

The low water level instrumentation closes all isolation valves except those in Groups 1, 4 and 5. This trip setting is adequate to prevent core uncovery in the case of a break in the largest line assuming a 60 second valve closing time. Required closing times are less than this, l l

Reactor pressure instrumentation is used for closure of Group 3 isolation valves and is set to trip at 176 psig. This prevents overpressurization of the RHR shutdown cooling piping. The isolation setpoint is chosen: (1) at a pressure below where the RHR piping could be overpressurized, (2) so that the isolation valves can close in the required time, and (3) at the point where the maximum differential pressure associated with the isolation valves is not exceeded.

The low low reactor water level instrumentation closes the Main Steam Line Isolation Valves, Main Steam Drain Valves, Recirc Sample Valves (Group 1) activates the CSCS subsystems, starts the emergency diesel generators and trips the recirculation pumps. This trip setting level was chosen to be high enough to prevent spurious actuation but low enough to initiate CSCS operation and primary system isolation so that no fuel damage will occur and so that post accident cooling can be accomplished and the guidelines of 10 CFR 100 will not be violated. For large breaks up to the complete circumferential break of a 28-inch recirculation line and with the trip setting given above, CSCS initiation and primary system isolation are initiated in time to meet the above criteria.

Revision 170 Amendment No. 105, 113, 151 68

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ATTACHMENT B BECO LETTER 94-097 AMENDED TECHNICAL SPECIFICATION PAGES i PAGE i

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r PNPS TABLE 3.2.A INSTRUMENTATION THAT INITIATES PRIMARY CONTAINMENT ISOLATIdN Operable Instrument Channels Per Trip System (1) .

Minimum Available Instrument Trip Level SettinE Action (2) 2(7) 2 Reactor Low Water Level 29" indicated level (3) A 'nd a D 1 1 Reactor High Pressure 110 ps 8 76 f5l6 D.

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• 2 Reactor Low-Low Water Level at or above -49 in. A .

indicated level (4) 2 2 Reactor liigh Water Level $48" indicated level (5) B 2(7) 2 High Drywell Pressure $2.5 psig A

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2 2 High Radiation Main Steam $7 times normal rated B '

Line Tunnel (9) full power background 2 2 Low Pressure Main Steam Line 2810 psig (8) B 2(6) 2 High Flow Main Steam Line 5140% of rated steam flow B 2 2 Main Steam Line Tunnel Exhaust Duct High Temperature $170 F B 2 2 Turbine Basement Exhaust Duct High Temperature 5150 F B 1 1 Reacter Cleanup System High Flow $300% of rated flow C 2 2 Reactor Cleanup System High Temperature $150 F C Revision 169 Amendment No. 86, 147, 150 45

PNPS TABIE 3.2.B (Cont'd)

Minimum # of INSTRUMENTATION THAT INITIATES OR CONTROLS THE CORE AND CON ,

Operable Instrument Channels Per Trip System (1) Trip Function Trip Level Setting Remarks 2

High Drywell Pressure 52.5 psig 1. Initiates Core Spray; LPCI;' HPCI.

2. In conjunction with Low-Low Reactor Water Level, 120 second time delay and LPCI or Core Spray pump running, initiates Auto Blowdown (ADS)

3. Initiates starting of Diesel Cenerators

4. In conjunction with Reactor Low Pressure initiates closure of HPCI valves. breaker containment isolation vacuum 1

Reactor Low Pressure 400 psig i 25 Permissivo for Opening Core Spray and LPCI 6.7GPsth Admission valves.

1 Reactor Low Pressure 5110 psig In conjunction with PCIS signal permits closure of RHR (LPCI) injection valves.

1 Reactor Low Pressure 400 psig i 25 In conjunction with Low-Low Reactor Water Level initiates Core Spray and LPCI.

2 Reactor Low Pressure 900 psig i 25 Prevents circuit. actuation of LPCI break detection 2

Reactor Low Pressure 100>P>50 psig IsolatesPressure HPCI and in conjunction with High Drywell initiates closure of HPCI (

vacuum breaker containment isolation valves.

Revision 167 Amendment No. 427 -113, 148 '

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BASES:

3.2 In addition to reactor protection instrumentation which initiates a reactor scram, protective instrumentation has been provided which initiates action to mitigate the consequences of accidents which are beyond the operator's ability to control, or terminates operator errors before they result in serious )

consequences. This set of specifications provides the limiting conditions of  !

coeration for the primary system isolation function, initiation of the core j cooling systems, control rod block, and standby gas treatment systems.

The objectives of the Specifications are, (i) to assure the effectiveness of the protective instrumentation when required by preserving its capability to tolerate a single failure of any component of such systems even during periods when portions of such systems are out of service for maintenance, and (ii) to prescribe the trip settings required to assure adequate performance. When l necessary, one channel may be made inoperable for brief intervals to conduct required functional tests and calibrations.

I Some of the settings on the instrumentation that initiate or control core and l containment cooling have tolerances explicitly stated where the high and low values are both critical and may have a substantial effect on safety. The set points of other instrumentation, where only the high or low end of the setting i has a direct bearing on safety, are chosen at a level away from the normal l operating range to prevent inadvertent actuation of the safety system involved  ;

and exposure to abnormal situations.  ;

i Actuation of primary containment valves is initiated by protective  !

instrumentation shown in Table 3.2.A which senses the conditions for which  ;

isolation is required. Such instrumentation must be available whenever l primary containment integrity is required. j The instrumentation which initiates primary system isolation is connected in a l dual bus arrangement.

The low water level instrumentation closes all isolation valves except l those in Groups 1, 4 and 5. This trip setting is adequate to prevent core I uncovery in the case of a break in the largest line assuming a 60 second valve i closing time. Required closing times are less than this.

> kWF j The low low reactor water level instrumentation closes the Main Steam Line i Isolation Valves, Main Steam Drain Valves, Recirc Sample Valves (Group 1) l activates the CSCS subsystems, starts the emergency diesel generators and I trips the recirculation pumps. This. trip setting level was chosen to be high enough to prevent spurious actuation but low enough to initiate CSCS operation and primary system isolation so that no fuel damage will occur and so that post accident cooling can be accomplished and the guidclines of 10 CFR 100 will not be violated. For large breaks up to the complete circumferential break of a 28-inch recirculation line and with the trip setting given above, CSCS initiation and primary system it,olation are initiated in time to meet the above criteria. .

Reactor pressure instrumentation is used for closure of 'iroup 3 isolation valves and is set to trip at 176 psig. This prevents overpressurization of the RHR shutdown cooling piping. The isolation setpoint is chosen: (1) at a pressure below where the RHR piping could be overpressurized, (2) so that the i. solation valves can close in the required time, and (3) at the point where the maximum differential pressure associated with the isolation valves is not exceeded.