ML20070A112
| ML20070A112 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/21/1994 |
| From: | NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20070A062 | List: |
| References | |
| NUDOCS 9406280197 | |
| Download: ML20070A112 (6) | |
Text
._m..__._.__.-____~..
....... = _ _ _ _ _ _ _ _ _ _ _ _ _.. _... _ _ _ _ _. _ _ _ _ _ _ _. _
' Attachment USNRC June 21., 1994 4
J l'
i 4
I i
1 Revised Technical Specification Pages i
i
?
l a
i 4
1 i
l 1
3 i
.I 5
f f
i i
4 I
I e
f I,
i
{
i i
i I
D i
9406280177 940621 PDR ADOCK 05000282 PDR P
v
.im__.--,,,,,-_,_,,,
-,-mm-_,,~..,..-.....____......_....-___.,-____..__
TS-xii TECHNICAL SPECIFICATIONS LIST OF TABLES TS TABLE TITLE 1-1 Operational Modes 3.5-1 Engineered Safety Features Initiation Instrument Limiting Set Points 3.5-2A Reactor Trip System Instrumentation 3.5-2B Engineered Safety Feature Actuation System Instrumentation 3.9-1 Radioactive Liquid Effluent Monitoring Instrumentation 3.9-2 Radioactive Caseous Effluent Monitoring instrumentation 3.14-1 Safety Related Fire Detection Instruments 3.15-1 Event Monitoring Instrumentation - Process & Containment 3.15-2 Event Monitoring Instrumentation - Radiation 4.1-1A Reactor Trip System Instrumentation Surveillance Requirements 4.1-1B Engineered Safety Feature Actuation System Instrumentation Surveillance Requirements 4.1-1C Miscellaneous Instrumentation Surveillance Requirements 4.1-2A Minimum Frequencies for Equipment Tests 4.1-2B Minimum Frequencies for Sampling Tests 4.2-1 Special Inservice Inspection Requirements 4.10-1 Radiation Environmental Monitoring Program (REMP)
Sample Collection and Analysis 4.10-2 RFMP - Maximum Values for the Lower Limits of Detection 4.10-3 REMP - Reporting Levels for Radioactivity Concentrations in Environmental Samples 4.12-1 Steam Generator Tube Inspection 4.13 1 Snubber Visual Inspection Interval 4.17-1 Radioactive Liquid Effluent Monitoring Instrumentation Surveillance Requirements 4.17-2 Radioactive Caseous Effluent Monitoring Instrumentation Surveillance Requirements 4.17-3 Radioactive Liquid Waste Sampling and Analysis Program 4.17-4 Radioactive Caseous Waste Sampling and Analysis Program 5.5-1 Anticipated Annual Release of Radioactive Material in Liquid Effluents From Prairie Island Nuclear Generating Plant (Per Unit) 5.5-2 Anticipated Annual Release of Radioactive Nuclides in Caseous Effluent From Prairie Island Nuclear Generating Plant (Per Unit) 6.1-1 Minimum Shift Crew Composition J
i
~
B.3.5-2 3.5 INSTRUMENTATION SYSTEM Bases continued Containment Spray Containment sprays are also actuated by a high containment pressure signal (Hi-Hi) to reduce containment pressure in the event of a loss-of-coolant or steam line break accident inside the containment.
The containment sprays are actuated at a higher containment pressure (approximately 50% of design containment pressure) than is safety injection (10% of design).
Since spurious actuation of containment spray is to be avoided, it is initiated on coincidence of high containment pressure sensed by three sets of one-out-of-two containment pressure signals provided for its actuation.
Containment Isolation A containment isolation signal is initiated by any signal causing auto-matic initiation of safety injection or may be initiated manually.
The containment isolation system provides the means of isolating the various pipes passing through the containment walls as required to prevent the release of radioactivity to the environment in the event of a loss-of-coolant accident.
Steam Line Isolation In the event of a steam line break, the steam line stop valve of the affected line is automatically isolated to prevent continuous, uncon-trolled steam release from more than one steam generator.
The steam lines I
are isolated on high containment pressure (Hi-Hi) or high steam line flow in coincidence with low T,y and safety injection or high steam flow (Hi-Hi) in coincidence with safety injection.
Adequate protection is afforded for breaks inside or outside the containment even when it is assumed that the steam line check valves do not function properly.
Containment Ventilation Isolation Valves in the containment purge and inservice purge systems automati-cally close on receipt of a Safety Injection signal or a high radiation signal.
Caseous and particulate monitors in the exhaust stream or a gaseous monitor in the exhaust stack provide the high radiation signal.
Ventilation System Isolation In the event of a high energy line rupture outside of containment, redundant isolation dampers in certain ventilation ducts are closed (Reference 4).
Safeguards Bus Voltage Relays are provided on buses 15, 16, 25, and 26 to detect undervoltage and degraded voltage (the voltage level at which safety related equipment may not operate properly).
Relays are not provided on 4 kV safeguards bus 27 to detect undervoltage and degraded voltage since voltage is monitored on the 4 kV source safeguards bus (i.e., bus 25 or bus 26 ) to which it is
B.3.5-3 3.5 INSTRUMNNTATION SYSTEM Bases continued Safeguards Bus Voltage (continued) connected.
Upon receipt of an undervoltage signal the automatic voltage restoring scheme is actuated after a short time delay which prevents actuation during normal transients (such ar motor ararting) and which allows protective relaying operation duritg faults. When degraded voltage is sensed, two time delays are actuated.
The first time delay is long enough to allow for normal transients. The first time delay annunciates that a sustained degraded voltage condition exists and enables logic which will ensure that voltage and timing are adequate for safety injection loads by automatically performing the following upon receipt of a safety injection signal:
1.
Auto start the diesel generator; 2.
Separate the bus from the grid; 3.
Load the bus onto the diesel generator; and 4.
Start the load sequencer (including safety injection loads).
Auxiliary Feedwater System Actuation The following signals automatically start the pumps and open the steam admission control valve to the turbine driven pump of the affected unit:
1.
Low-low water level in either steam generator 2.
Trip of both main feedwater pumps 3.
Safety Injection signal 4.
Undervoltage on both 4.16 kV normal buses (turbine driven pump only)
Manual control from both the control room and the llot Shutdown Panel are also availabic.
The design provides assurance that water can be supplied to the steam generators for decay heat removal when the normal feedwater system is not available.
Underfrequency 4kV Bus The underfrequency 4kV bus trip does not provide a direct reactor trip signal to the reactor protection system. A reactor coolant pump bus underfrequency signal from both buses provides a trip signal to both reactor coolant pump breakers. Trip of the reactor coolant pump breakers results in a reactor trip. The underfrequency trip protects against postulated flow coastdown events.
Limiting Instrument Setpoints 1.
The high containment pressure limit is set at about 10% of the maximum internal pressure.
Initiation of Safety injection protects against loss of coolant (Reference 2) or steam line break accidents as discussed in the safety analysis.
1
B.3.5-4 3.5 INSTRUMENTATION SYSTEM Bases continued Limiting Instrument Setpoints (continued) 2.
The Hi-Hi containment pressure limit is set at about 50% of the maximum internal pressure for initiation of containment spray and at about 30% for initiation of steam line isolation.
Initiation of Containment Spray and Steam Line Isolation protects against large loss of coolant (Reference 2) or steam line break accidents (Reference 3) as discussed in the safety analysis.
3.
The pressurizer low pressure limit is set substantially below system operating pressure limits. However, it is sufficiently high to protect against a loss of coolant accident as shown in the safety analysis (Reference 2).
4 The steam line low pressure signal is lead / lag compensated and its set-point is set well above the pressure expected in the event of a large steam line break accident as shown in the safety analysis (Reference 3).
5.
The high steam line flow limit is set at approximately 20% of nominal full-load flow at the no-load pressure and the high-high steam line flow limit is set at approximately 120% of nominal full-load flow at the full load pressure in order to protect against large steam break accidents. The coincident low T,y setting limit for steam line isolation initiation is set below its hot shutdown value.
The safety analysis shows that these settings provide protection in the event of a large steam break (Reference 3).
6.
Steam generator low-low water level and 4.16 kV Bus 11 and 12 (21 and 22 in Unit 2) low bus voltage provide initiation signals for the Auxiliary Feedwater System.
Selection of these setpoints is discussed in the Bases of Section 2.3 of the Technical Specification.
7.
High radiation signals providing input to the Containment Ventilation Isolation circuitry are set in accordance with the Radioactive Effluent Technical Specifications.
The setpoints are established to prevent exceeding the limits of 10 CFR Part 20 at the SITE B00NDARY.
8.
The degraded voltage protection setpoint is 294.8% and $96.2% of nominal 4160 V bus voltage. Testing and analysis have shown that all safeguards loads will operate properly at or above the minimum degraded voltage setpoint.
The maximum degraded voltage setpoint is chosen to prevent unnecessary actuation of the voltage restoring scheme at the minimum expected grid voltage.
The first degraded voltage time delay of 8 i 0.5 seconds has been shown by testing and analysis to be long enough to allow for normal transients (i.w., motor starting and fault clearing).
It is also longer than the time required to start the safety injection pump at minimum voltage. The second degraded voltage time delay is provided to allow the degraded voltage condition to be corrected within a time frame which will not cause damage to permanently connected Class 1E loads.
+
B.3.5-5 3.5 IN'STRUMENTATION SYSTEM Bases continued Limiting Instrument Setpoints (continued)
The undervoltage setpoint is 75 2.5% of nominal bus voltage. The j
minimum setpoint ensures equipment operates above the limiting value of 75% (of 4000 V) for one minute operation. The 75% maximum setpoint is chosen to prevent unnecessary actuation of the voltage restoring scheme during voltage dips which occur during motor starting.
The undervoltage time delay of 4 i 1.5 reconds has been shown by testing and analysis to be long enough to allow for normal transients and short enough to operate prior to the degraded voltage logic, providing a rapid transfer to an alternate source.
Instrument Operating Conditions During plant operations, the complete instrumentation systems will normally be in service. Reactor safety is provided by the Reactor Protection System, which automatically initiates appropriate action to i
prevent exceeding established limits.
Safety is not compromised, however, by continuing operation with certain instrumentation channels out of service since provisions were made for this in the plant design. This specification outlines limiting conditions for operation necessary to preserve the effectiveness of the Reactor Control and Protection System when any one or more of the channels is out of service.
Almost all reactor protection channels are supplied with sufficient redundancy to provide the capability for CHANNEL CALIBRATION and test at power.
Exceptions are backup channels such as reactor coolant pump breakers. The removal of one trip channel on process control equipment is accomplished by placing that channel bistable in a tripped mode; e.g.,
a i
two-out-of-three circuit becomes a one-out-of-two circuit. The source and intermediate range nuclear instrumentation system channels are not intentionally placed in a tripped mode since these are one-out of-two trips, and the trips are therefore bypassed during testing.
Testing does not trip the system unless a trip condition exists in a concurrent i
channel.
References 1.
USAR, Section 7.4.2 2.
USAR, Section 14.6.1 l
3.
USAR, Section 14.5.5 4
FSAR, Appendix I
,